The story

How many surface ships have reached the North Pole?

How many surface ships have reached the North Pole?


We are searching data for your request:

Forums and discussions:
Manuals and reference books:
Data from registers:
Wait the end of the search in all databases.
Upon completion, a link will appear to access the found materials.

I realize that the nuclear-powered icebreaker Arktika (Soviet Union) reached the north pole on August 17, 1977. However, I would like to know of any other ships that have also reached the North Pole.

[edit]

I realize I should probably have specified Geographic vs. Magnetic North Poles, but either is nice especially if specified.


This quote came from the first paragraph of this page, which is in Russian. This is an approximate translation.

By September 2007 the North Pole had been visited 66 times by different surface ships: 54 times by Soviet and Russian icebreakers, 4 times by Swedish Oden, 3 times by German RV Polarstern, 3 times by USCGC Healy and USCGC Polar Sea, and once by CCGS Louis S. St-Laurent and by Norwegian Vidar Viking.

So, quite a few have reached the Geographic North Pole. I can't find a more recent number, however.


The Magnetic North Pole actually moves around rather a lot. Generally over the last 150 years or so it has been in Canadian territory, but often it is on dry (well… frozen) land.

It isn't exactly on your typical tourist trade routes, but it generally isn't nearly as difficult to reach as the Geographic North Pole. Inuit have traditionally lived on those islands, and some still do today.

Wikipedia credits three sets of Europeans as being the first to lead expiditions with the express purpose of finding the Magnetic North Pole. They are James Clark Ross, Roald Amundsen, and Canadians Paul Serson and Jack Clark.

However, given that the Inuit have lived there for centuries, and folks of Icelandic extraction several hundred years earlier had settlements at nearby Greenland and North America and explored all the nearby islands, it is tough to be too impressed.


The Crazy Dangers of Submarines Under Ice: To the North Pole & Back

Navies for centuries have been interested in operating in Arctic conditions. Whether it be in search of the northwest passage or whether to maintain a supply line to the Soviet Union during World War II, there has always been a desire and need by those afloat to conquer the frozen north.

Surface ships had tried, and inevitably failed, to reach the highest latitudes. But after the advent of submarines, people began to imagine that perhaps the North Pole was attainable from below the surface. It was only well into the 20th century that this notion became a practical reality.

Operating a submarine under polar ice caps is simple in concept but highly dangerous. The ice below is uneven and often very thick. In the early days of submarines, there were no sonar systems that could detect where the ice was in relation to the boat. If there was an emergency that required an emergency surfacing, it was likely that the vessel would crash catastrophically into the ice.

By the 1930s, technology had improved enough to make the dream of polar submarine operations plausible, albeit still dangerous. In August 1931, the first submarine expedition to operate in the Arctic launched. The Australian explorer and geographer Sir Hubert Wilkens acquired the submarine O-12 from the U.S. Navy and refitted it as the Nautilus.

US submarine USS Nautilus/USS O-12 at quay in Bergen, Norway shortly before being scuttled

The submarine’s new design was specific for ice operations, complete with an escape tube topped with a saw to cut through the ice pack and a mechanical probe to gauge the depth of the boat relative to the ice. Both were not fully tested. The expedition, however, was cut short by damaged diving planes.

Still, the submarine ran successfully under ice, even reaching 82 degrees north. It was obvious that with improved technology, submarines could reach the Pole.

The next major submarine polar expedition was the U.S. Navy’s Operation Nanook in 1946. While the mission was not meant specifically to reach the North Pole, its contributions were significant toward the development of Arctic naval operations. New equipment was tested, and ice-sounding gear was improved which enabled a watershed moment in submarine history 12 years later.

USS Atule during Operation Nanook (1946).

In 1958, the U.S. Navy’s first nuclear-powered submarine, also named Nautilus, was given a secret mission code named “Operation Sunshine.” Its purpose was to reach the North Pole.

The submarine left Pearl Harbor on July 23, 1958 and sailed to the Bering Straits. From there, Commander William R. Anderson gave the order to dive and make for the Fram Straits, crossing the Pole en route.

Anderson aboard the Nautilus

One hundred and sixteen men sailed on into unknown waters until at 11:15 p.m. on August 3, 1958, Anderson announced to his crew, “For the world, our country, and the Navy – the North Pole.”

Navigator’s report- Nautilus, 90°N, 19-15U, 3 August 1958, zero to North Pole.

Their secret mission was soon not so secret. For the deed, the submarine received the first peacetime Presidential Unit Citation. The submariners of the Nautilus were feted in New York City with a ticker tape parade. One crewman recalled feeling like a rock star. Today, the Nautilus has been preserved at the Submarine Force Museum in Groton, Connecticut.

The USS Nautilus permanently docked at the US Submarine Force Museum and Library, Groton, CT.Photo: Victor-ny CC BY-SA 3.0

Several months later, the U.S. Navy made another mark on naval history. On March 17, 1959, the submarine U.S.S. Skate managed to surface through gaps in the ice at the North Pole.

It was a terrifying moment since the submarine had to negotiate between ice floes that could easily sink the craft. James F. Calvert, the commanding officer of Skate, was relieved when his boat emerged safe and sound. He then exited the submarine.

Later, Calvert recalled the awe of the moment. “The first impression was being in an infinite desert of ice…. There was nothing but a flat patchwork maze of ice floes in every direction. Directly before us the slender black hull of the submarine contrasted with the deep blue of the calm lake water and the stark white of the surrounding ice.”

USS Skate (SSN-578) with an ice pack behind her

He and his crew were met almost immediately by a polar bear, which had probably never seen a nuclear-powered submarine before.

Skate’s crew planted the American flag and scattered the ashes of Sir Hubert Wilkens into the Arctic winds.

In the decades that followed, other countries followed suit – the Soviet Union in 1962 and the United Kingdom in 1971. By the early 21st century receding ice caps had led to the emergence of new waterways and access to resources, placing the region into greater geopolitical significance.

Sir George Hubert Wilkins (1888–1958), Australian polar explorer, ornithologist, pilot, soldier, geographer and photographer

Joint allied operations organized by the United States Navy have become a biennial occurrence. Dubbed ICEX, the five-week exercises feature under-ice weapons testing, the collection of scientific data, and diving operations.

The 2018 exercises were conducted out of a temporary base named Camp Skate. The base, which is multinational in flavor with representatives from several NATO countries, contains kitchens, a medical bay, lavatories, and warm storage for items that cannot be exposed to the polar environment. The base is also equipped with a diving shelter.

The Seawolf-class fast-attack submarine USS Connecticut (SSN 22) surfaces through the ice as it participates in Ice Exercise (ICEX) 2018.

Diving is perhaps the most punishing of all the Arctic exercises. In the 2018 operation, divers from the Mobile Diving and Salvage Unit Two, Underwater Construction Team One, and Coast Guard took dips below the ice to recover training torpedoes which contain important testing data.

The divers are specially trained for the work since the ice and water temperature, which is just below 29 degrees, make it especially dangerous.

But the highlight of ICEX is the thrill of watching massive Los Angeles-class and Seawolf-class fast attack submarines surface through desolate ice fields.

Videos of the event are wildly popular and reveal that some cold weather maintenance tasks, like scraping ice off your vehicle, are common to submariners and suburbanites alike. But instead of plastic ice scrapers, such as the ones you might use on your Ford, the crews of these submarines use large steel crowbars to clear ice from their conning towers.


USS Nautilus (SSN 571)

USS NAUTILUS was the Navy's first nuclear-powered vessel and the fourth ship in the Navy to bear the name. She was also the world's first ship to reach the geographic North Pole. Both decommissioned and stricken from the Navy list on March 3, 1980, the NAUTILUS became a museum on May 20, 1982 and is now located at the Historic NAUTILUS & Submarine Force Museum at New London, Conn. Click here for a photo tour of the preserved NAUTILUS.

General Characteristics: Awarded: August 2, 1951
Keel laid: June 14, 1952
Launched: January 21, 1954
Commissioned: September 30, 1954
Decommissioned: March 3, 1980
Builder: Electric Boat Division of General Dynamics Corporation, Groton, CT.
Propulsion system: one nuclear reactor
Propellers: two
Length: 324 feet (98.75 meters)
Beam: 27.8 feet (8.47 meters)
Draft: 22 feet (6.7 meters)
Displacement: Surfaced: approx. 3,530 tons Submerged: approx. 4,090 tons
Speed: Surfaced: approx. 22 knots Submerged: approx. +20 knots
Armament: six 533 mm torpedo tubes
Crew: 13 Officers, 92 Enlisted

This section contains the names of sailors who served aboard USS NAUTILUS. It is no official listing but contains the names of sailors who submitted their information.

Accidents aboard USS NAUTILUS:

USS NAUTILUS was laid down 14 June 1952, President Harry S. Truman officiating, at the Electric Boat Co., Division of General Dynamics Corp., Groton, Connecticut launched 21 January 1954 sponsored by Mrs. Dwight D. Eisenhower, wife of President Eisenhower, and commissioned 30 September 1954, Comdr. E. P. Wilkinson in command.

Following commissioning NAUTILUS remained at dockside for further construction and testing until 17 January 1955. Then, at 1100, her lines were cast off and she was "underway on nuclear power." Trials followed and on 10 May NAUTILUS headed south for shakedown. She remained submerged while enroute to Puerto Rico, covering 1,381 miles in 89.8 hours, the longest submerged cruise, to that date, by a submarine, and at the highest sustained submerged speed ever recorded for a period of over one hour's duration. Throughout 1955, and into 1957, she investigated the effects of the radically increased submerged speed and endurance, such changes in submerged mobility having virtually wiped out progress in anti-submarine warfare techniques. The airplane and radar, which helped defeat submarines in the Atlantie during World War II, proved ineffective against a vessel which did not need to surface, could clear an area in record time, and swiftly change depth simultaneously.

On 4 February 1957, NAUTILUS logged her 60,000th nautical mile to bring to reality the achievements of her fictitious namesake in Jules Verne's 20,000 Leagues Under the Sea. In May she departed for the Pacific Coast to participate in coastal exercises and the fleet exercise, operation "Home run," which acquainted units of the Pacific Fleet with the capabilities of nuclear submarines.

NAUTILUS returned to New London 21 July and departed again 19 August for her first voyage, of 1,383 miles, under polar pack ice. Thence, she headed for the Eastern Atlantic to participate in NATO exercises and conduct a tour of various British and French ports where she was inspected by defense personnel of those countries. She arrived back at New London 28 October, underwent upkeep, and then conducted coastal operations until the spring.

On 25 April 1958 she was underway again for the West Coast. Stopping at San Diego, San Francisco, and Seattle she began her history making Polar transit, operation "Sunshine," as she departed the latter port 9 June. On 19 June she entered the Chukchi Sea, but was turned back by deep draft ice in those shallow waters. On the 28th she arrived at Pearl Harbor to await better ice conditions. By 23 July her wait was over and she set a course northward. She submerged in the Barrow Sea Valley 1 August and on 3 August, at 2315 (EDST) she became the first ship to reach the geographic North Pole. From the North Pole, she continued on and after 96 hours and 1830 miles under the ice, she surfaced northeast of Greenland, having completed the first successful voyage across the North Pole.

Proceeding from Greenland to Portland, England, she received the Presidential Unit Citation, the first ever issued in peace time, from American Ambassador J. H. Whitney, and then set a westerly course which put her into the Thames River estuary at New London 29 October. For the remainder of the year she operated from her homeport, New London, Connecticut.

Following fleet exercises in early 1959, NAUTILUS entered the Portsmouth Naval Shipyard, for her first complete overhaul (28 May 1959 - 15 August 1960). Overhaul was followed by refresher training and on 24 October she departed New London for her first deployment with the 6th Fleet in the Mediterranean, returning to her homeport 16 December.

NAUTILUS operated in the Atlantic, conducting evaluation tests for ASW improvements, participating in NATO exercises and, during the fall of 1962, in the naval quarantine of Cuba, until she headed east again for a two month Mediterranean tour in August 1963. On her return she joined in fleet exercises until entering the Portsmouth Naval Shipyard for her second overhaul 17 January 1964. On 2 May 1966, NAUTILUS returned to her homeport to resume operations with the Atlantic Fleet. For the next year and a quarter she conducted special operations for ComSubLant and then in August 1967, returned to Portsmouth, for another year's stay, following which she conducted exercises off the southeastern seaboard. She returned to New London in December 1968.

The submarine spent most of the next two years in an extended upkeep and restricted availability status, carrying out independent submarine type training while intermittently tending to new equipment troubles. NAUTILUS also conducted half a dozen ASW exercises with other surface ships and submarines in the Narragansett Bay, Virginia Capes and Jacksonville operating areas. In October 1970, she also participated in ASW Exercise "Squeezeplay VI", an evaluation of the new AN/SQS-26 sonar system and the effectiveness of coordinated air, surface and submarine forces against an "opposing force" (i.e. NAUTILUS) of nuclear-powered enemy submarines. The submarine participated in three more iterations of those exercises in the spring and summer of 1971, as well as providing evaluation services for aircraft-mounted ASW systems, with a final role in Exercise "Squeezeplay XI" conducted in June 1972. She then entered the General Dynamics Shipyard at Groton for an overhaul on 15 August.

After completing post-overhaul sea trials on 23 December 1974, NAUTILUS conducted an outstanding shakedown and refresher training cruise followed by Fleet Exercise "Agate Punch" in April. Success in both endeavors allowed the submarine her first Mediterranean deployment in a decade, with the boat visiting La Spezia, Italy, soon after her arrival there on 6 July 1975. The cruise took the submarine into the central Mediterranean and Ionian Sea, where she trained 6th Fleet units in ASW techniques, and then on to the North Atlantic. After participating in a special operation the warship returned home, returning to New London via Holy Loch, Scotland, on 20 December.

Following a holiday standown period, NAUTILUS began a year long series of West Indies cruises in the spring of 1976, conducting weapons certification tests, supporting special forces exercises and conducting equipment development evaluations for the Chief of Naval Operations. The following April, the submarine departed New London for another Mediterranean cruise, where she participated in "Dawn Patrol" and other NATO exercises. During the cruise she visited Lisbon, Portugal Sousse, Tunisia La Maddalena, Sardinia and Taranto and Naples in Italy before returning to New London in September 1977.

NAUTILUS began 1978 slowly, with a six-week upkeep followed by a short dependents cruise in early March. Later that month, the submarine conducted a six-week oceanographic research deployment cruise, which included a port visit to Bermuda. After a summer of interim repair work to replace faulty hydrophones, the crew observed the twentieth anniversary of the historic polar voyage to the north pole on 3 August. This milestone was followed by another in December, when NAUTILUS logged her 500,000 mile on nuclear power.

On 9 April 1979, NAUTILUS departed Groton on her final voyage, steaming south to the Panama Canal via Guantanamo Bay and Cartagena, Columbia. From there she cruised north and reached Mare Island Naval Shipyard, Vallejo, Ca., on 26 May - her last day underway on nuclear power - to begin inactivation procedures. NAUTILUS decommissioned at Mare Island on 3 March 1980.

In recognition of her pioneering role in the practical use of nuclear power, NAUTILUS was designated a National Historic Landmark by the Secretary of the Interior on 20 May 1982. Following an extensive historic ship conversion at Mare Island Naval Shipyard, the submarine was towed to Groton, Connecticut, arriving on 6 July 1985. There, on 11 April 1986, eighty-six years to the day after the establishment of the U.S. Submarine Force, historic ship NAUTILUS and the Submarine Force Museum opened to the public as the first exhibit of its kind in the world. The museum ship continues to serve as a link in both Cold War-era history and the birth of the nuclear age.

USS NAUTILUS Image Gallery:

The photos below were taken by me on August 22, 2010, during a visit to the USS NAUTILUS museum at Groton, CT.


North Pole

Our editors will review what you’ve submitted and determine whether to revise the article.

North Pole, northern end of Earth’s axis, lying in the Arctic Ocean, about 450 miles (725 km) north of Greenland. This geographic North Pole does not coincide with the magnetic North Pole—to which magnetic compasses point and which in the early 21st century lay north of the Queen Elizabeth Islands of extreme northern Canada at approximately 82°15′ N 112°30′ W (it is steadily migrating northwest)—or with the geomagnetic North Pole, the northern end of Earth’s geomagnetic field (about 79°30′ N 71°30′ W). The geographic pole, located at a point where the ocean depth is about 13,400 feet (4,080 metres) deep and covered with drifting pack ice, experiences six months of complete sunlight and six months of total darkness each year.


If you want to go somewhere you’ve never been, what do you do first? Pull up MapQuest on your web browser and input your destination? Or, do you have a GPS unit for your car? Maybe you use a printed map or an atlas. Back in the early days of polar discovery, none of these tools were available. In fact, much of the Arctic and Antarctic wasn’t even mapped yet.

COMPETING CLAIMS

In 1909 a bitter controversy involved two American explorers, Frederick A. Cook and Robert E. Peary. Both claimed to be first to reach the North Pole on foot.

Finding the North Pole is tricky. Unlike the South Pole, which lies on a land mass, the North Pole is actually in a vast sea covered by floating ice. Since the ice is constantly in motion, planting a flag or otherwise marking the spot is futile. In addition, magnetic compasses are rendered useless in the polar regions due to the magnetic field at the poles. Determining one’s position, then, is based on calculations using a chronometer – basically a highly efficient time piece – and a sextant – a navigational instrument that allowed an explorer to compute latitude based on the position of the sun.

Frederick A. Cook in furs, circa 1909. The Ohio State University Archives, Frederick A. Cook Society Collection, RG 56.17, image #34_2a.

Robert E. Peary, circa 1909. The Ohio State University Archives, Frederick A. Cook Society Collection, RG 56.17, image #34_34y.

In September of 1909, Frederick A. Cook, a medical doctor from New York, announced that he and two Inuit companions had reached the North Pole on April 21, 1908. He claimed that bad weather conditions and drifting ice had prohibited his southward return and he and his companions were forced to winter over in an ice cave. A week later, Robert E. Peary, a civil engineer and a commander in the U.S. Navy, announced that he had reached the North Pole, accompanied by his long-time companion Matthew Henson, and he denounced Cook as a fraud. In any case, Peary had some very powerful sponsors, including the New York Times as well as the National Geographic Society.

Though Cook appeared to welcome Peary’s announcement and was willing to share the limelight, Peary was furious at Cook’s attempt to “steal” his victory. By all accounts, Peary was a driven man, and this was his third attempt at the North Pole. Henson, an African-American, had traveled with Peary on all of his “farthest north” expeditions. Though Peary recognized Henson’s contribution to his success, stating, “Henson was the best man I had with me for this kind of work,” he also minimized Henson’s role after the fact.

Complicating the situation for Cook was that his claim to have been the first to summit Mt. McKinley (in Alaska) in 1906 had been called into question. Cook’s critics felt that if he lied about Mt. McKinley, then certainly he was lying about the North Pole as well. It didn’t take long for Peary’s claim to overshadow the claim of the rather unknown Cook.

Shortly after they returned from the Pole, Cook and Peary each published their version of the truth in books that discussed their expeditions and discoveries in minute detail. The books became bestsellers and also fueled the public debate.

Cover image from booklet, “At the Pole with Cook and Peary,” 1909. The Ohio State University Archives, Frederick A. Cook Society Collection, RG 56.17, image #9_50.

The burden of proof for polar discoveries lies on the explorer. Without modern methods of GPS mapping and plotting of locations, how was this done? Polar explorers during this time were expected to keep detailed, handwritten diaries of their travels, including navigational calculations. Unlike today, when travelers might blog about their journeys to places unknown, taking hundreds of digital images and video along the way, polar explorers in 1909 were much more limited by their tools. Even radio transmission was limited during this time period explorers had to get to the nearest populated city in order to share their discoveries with the world.

A lot of research and attention has been given to the Cook/Peary North Pole controversy over the last 90 years. Each side has its supporters as well as detractors. Some researchers have concluded that neither one actually got to the North Pole. It is fascinating that there seems to be no end to the debate in sight, even after all of these years. Researchers continue the hunt for primary documents that might lead them to the answers. The Byrd Polar Research Center Archival Program holds the papers of the Frederick A. Cook Society, while Cook’s diaries and other personal papers are held in the Library of Congress in Washington, D.C. Robert E. Peary’s papers can be found in the U.S. National Archives in Washington, D.C.

CONTINUING CONTROVERSIES

The North Pole controversy does not end with Cook and Peary fast forward from 1909 to 1926. By this time, technological advances changed the focus of polar exploration. Simply getting there was no longer the primary goal scientific study of the polar regions included geological investigation, advances in radio transmission, weather observation, and continued mapping of the vast Arctic and Antarctic regions.

Richard E. Byrd, officially retired from the U.S. Navy, was a proponent of aerial investigation. He earned his pilot’s wings after an injury to his foot forced him to redirect his naval career. After participating in the Greenland Expedition of 1925, Byrd believed more than ever in the feasibility of flight in the Arctic. Byrd was the commander of the aviation unit on this expedition. Though bad weather and mechanical breakdowns hampered the success of flight on the Greenland Expedition, Byrd continued to have faith that airplanes would indeed be successful in investigation of the polar regions.

Richard E. Byrd, circa 1920s. The Ohio State University Archives, Papers of Admiral Richard E. Byrd, RG 56.1, image #7638_13.

In 1926, with the backing of the National Geographic Society and private donations from many influential people of the time, such as Edsel Ford, John D. Rockefeller, Vincent Astor, and others, Byrd was able to secure enough money to lease a ship and buy an airplane and all the needed supplies to embark on a north polar flight. Other major investors included the New York Times, Current News Features, and Pathe News, a producer of newsreels. In exchange for their investments, Byrd signed contracts guaranteeing his story to the various media.

After extensive organization and planning, delays and complications, Byrd finally took off in his plane, the Josephine Ford, on May 9, 1926, at 12:30 a.m. Floyd Bennett did most of the piloting, with Byrd as navigator. The aerial navigator’s role was complex, operating several instruments at a time. The sun compass (developed specifically for Byrd by Albert Bumstead of the National Geographic Society) was used to determine direction, a chronometer to find longitude, a bubble sextant for latitude, and smoke bombs and drift indicator to determine the influence of wind on the plane. At 9:02 a.m., Byrd’s calculations indicated that they were at the North Pole. After taking motion pictures and readings, they circled and returned to Spitsbergen, Norway.

Pathe cameraman filming the Josephine Ford as it was being prepared for flight to the North Pole. The Ohio State University Archives, Papers of Admiral Richard E. Byrd, RG 56.1, image #7739_6.

Byrd received numerous honors for this accomplishment and became a public hero. The National Geographic Society examined Byrd’s records and confirmed his navigational calculations and instrumentation as accurate. Almost immediately, however, some were skeptical of Byrd’s accomplishment. Most doubters based their concern on the belief that the Josephine Ford was incapable of making the round-trip flight in only 16 hours. The most vocal skeptics came forward after Byrd’s death in 1957. One even stated that Byrd’s pilot, Floyd Bennett, confessed that he and Byrd had actually flown out of sight and circled until enough time had passed for Byrd to claim they had made it to the North Pole.

The North Pole flight controversy simmered for decades after Byrd’s death. It was reignited in 1996 when an Ohio State University archivist, Raimund E. Goerler, discovered Byrd’s North Pole expedition diary among Byrd’s papers. The Byrd papers came to the Ohio State University in the mid-1980s, but remained unprocessed until the 1990s, when a U.S. Department of Education grant provided the funding to process the collection.

The diary went undiscovered for a time, probably due to the printed title, “Diary, 1925.” Indeed Byrd did use the diary in 1925 however, since he did not write on all of the pages, he used it again in 1926 and in 1927. Sometimes he corrected the printed date at the top of the page and sometimes he did not. Most entries are written in pencil and the entries are out of order chronologically. Some pages have notes and mathematical calculations, while several pages show signs of erasure, though the erasures are not thorough and can easily be read. There are notes written by Byrd to his pilot Floyd Bennett, during the flight, due to cockpit noise which made it difficult to communicate verbally. It is apparent that Byrd used the diary as both a daily journal and a convenient notepad.

In light of the discovery of the diary, the existing evidence was analyzed and reanalyzed. Some believe that the erasures present evidence that Byrd was lying about achieving the Pole others believe that this simply shows that he made a calculation error and was correcting it. Various experts in navigation and astronomy studied the diary and its calculations and notes – and came up with different conclusions!

So how can we know whether Cook or Peary got to the North Pole first? And how can we say with certainty that Richard E. Byrd did or did not fly over the North Pole in 1926? These questions may be impossible to answer. However, researchers continue to study the collections of primary documents, hoping to find additional clues that will lead them to the answers.

RESOURCES

Byrd Polar Research Center Archival Program
Read about polar explorers and view images and online exhibits related to the history of polar exploration.

Our Polar Past: Using the History of Polar Exploration in the Science Classroom
This article from The Science Teacher, a member journal of the National Science Teachers Association, presents research on the best resources and strategies for incorporating polar exploration history into the science classroom. Though the article is aimed at high school science teachers, teachers of all grade levels will benefit from the article’s timelines, lists of polar biographies, and general instructional strategies. The article is free for NSTA members and .99 for nonmembers.

The Frederick A. Cook Society
Information about Frederick Cook and the continuing controversy surrounding his claim of reaching the North Pole in 1909.

ExploraPoles
This page from the International Polar Foundation’s web site profiles current polar explorers. Pictures and short biographies are included.

REFERENCES

Byrd, Richard, E. 1998. To the Pole: The Diary and Notebook of Richard E. Byrd, 1925-1927. Edited by Raimund E. Goerler. Columbus, OH: Ohio State University Press. Available online at http://www.ohiostatepress.org/index.htm?/books/book%20pages/goerler%20to.htm

Cook, Frederick A. 1911 My Attainment of the Pole: Being the Record of the Expedition that First Reached the Boreal Center, 1907-1909, With the Final Summary of the Polar Controversy. New York: The Polar Publishing Company

Peary, Robert E. 1910. The North Pole: Its Discovery In 1909 Under the Auspices of the Peary Arctic Club. New York: Frederick A. Stokes Company.

NATIONAL SCIENCE EDUCATION STANDARDS: SCIENCE CONTENT STANDARDS

The entire National Science Education Standards document can be read online or downloaded for free from the National Academies Press web site. The content standards are found in Chapter 6.

While explorers are usually part of a geography or social studies curriculum, including lessons on polar explorers (past and present) can also meet the History and Nature of Science Content Standard for grades K-4 and 5-8:

K-4 History and Nature of Science

Science as a Human Endeavor

  • Science and technology have been practiced by people for a long time.
  • Men and women have made a variety of contributions throughout the history of science and technology.
  • Although men and women using scientific inquiry have learned much about the objects, events, and phenomena in nature, much more remains to be understood. Science will never be finished.
  • Many people choose science as a career and devote their entire lives to studying it. Many people derive great pleasure from doing science.

5-8 History and Nature of Science

Science as a Human Endeavor

  • Women and men of various social and ethnic backgrounds – and with diverse interests, talents, qualities, and motivations – engaged in the activities of science, engineering, and related fields such as the health professions. Some scientists work in teams, and some work alone, but all communicate extensively with others.
  • Science requires different abilities, depending on such factors as the field of study and type of inquiry. Science is very much a human endeavor, and the work of science relies on basic human qualities, such as reasoning, insight, energy, skill, and creativity – as well as on scientific habits of mind, such as intellectual honesty, tolerance of ambiguity, skepticism, and openness to new ideas.
  • Many individuals have contributed to the traditions of science. Studying some of these individuals provides further understanding of scientific inquiry, science as a human endeavor, the nature of science, and the relationship between science and society.
  • In historical perspective, science has been practiced by different individuals in different cultures. In looking at the history of many peoples, one finds that scientists and engineers of high achievement are considered to be among the most valued contributors to their culture.

This article was written by Laura Kissel and Lynn Lay. For more information, see the Contributors page. Email Kimberly Lightle, Principal Investigator, with any questions about the content of this site.

Copyright December 2009 – The Ohio State University. This material is based upon work supported by the National Science Foundation under Grant No. 0733024. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. This work is licensed under an Attribution-ShareAlike 3.0 Unported Creative Commons license.


Life After the North Pole 

Triumphant when they returned, Peary received many accolades for his accomplishment, but — an unfortunate sign of the times — as an African American, Henson was largely overlooked. And while Peary was lauded by many for his achievement, he and his team faced wide skepticism, with Peary having to testify before Congress about allegedly reaching the North Pole due to a lack of verifiable proof. The truth about Peary&aposs and Henson&aposs 1909 expedition still remains clouded.

Henson spent the next three decades working as a clerk in a New York federal customs house, but he never forgot his life as an explorer. He recorded his Arctic memoirs in 1912, in the book A Negro Explorer at the North Pole. In 1937, a 70-year-old Henson finally received the acknowledgment he deserved: The highly regarded Explorers Club in New York accepted him as an honorary member. In 1944 he and the other members of the expedition were awarded a Congressional Medal. He worked with Bradley Robinson to write his biography, Dark Companion, which was published in 1947.


VISIONS OF THE NORTH

In 1857, Lady Franklin commissioned one more expedition under Francis Leopold McClintock to investigate Rae's report. In the summer of 1859, the McClintock party found a document in a cairn on King William Island left by Franklin's second-in-command, giving the date of Franklin's death. The message, dated April 25, 1848, also reported that the ships had been trapped in the ice, that many others had died, and that the survivors had abandoned the ships and headed south towards the Back River.

McClintock also found several bodies and an astonishing amount of abandoned equipment, and heard more details from the Inuit about the expedition's disastrous end. In a cairn near the site he found one final note, which related how the ships had become trapped in the ice in 1847. Sir John Franklin himself had died in June of that year, and when the ice did not release the ships in the spring of 1848, his second-in-command Francis Crozier ordered them abandoned. Over a hundred officers and crew man-hauled sledges filled with supplies over land, eventually succumbing to a combination of exhaustion, exposure, scurvy, and (though they didn't know it) possible lead poisoning from their tinned provisions.


Contents

The search for Terra Australis Incognita Edit

Aristotle speculated, "Now since there must be a region bearing the same relation to the southern pole as the place we live in bears to our pole. ". [1]

According to Māori oral history in New Zealand, Hui Te Rangiora (also known as Ūi Te Rangiora) and his crew explored Antarctic waters in the early seventh century on the vessel Te Ivi o Atea. [2] Accounts name the area Te tai-uka-a-pia, which describes a 'frozen ocean' and 'arrowroot', which resembles fresh snow when scraped. [2] [3]

It was not until Prince Henry the Navigator began in 1418 to encourage the penetration of the torrid zone in the effort to reach India by circumnavigating Africa that European exploration of the southern hemisphere began. [4] In 1473, Portuguese navigator Lopes Gonçalves proved that the equator could be crossed, and cartographers and sailors began to assume the existence of another, temperate continent to the south of the known world.

The doubling of the Cape of Good Hope in 1487 by Bartolomeu Dias first brought explorers within touch of the Antarctic cold, and proved that there was an ocean separating Africa from any Antarctic land that might exist. [4]

Ferdinand Magellan, who passed through the Straits of Magellan in 1520, assumed that the islands of Tierra del Fuego to the south were an extension of this unknown southern land, and it appeared as such on a map by Ortelius: Terra australis recenter inventa sed nondum plene cognita ("Southern land recently discovered but not yet fully known"). [5]

European geographers connected the coast of Tierra del Fuego with the coast of New Guinea on their globes, and allowing their imaginations to run riot in the vast unknown spaces of the south Atlantic, south Indian and Pacific oceans they sketched the outlines of the Terra Australis Incognita ("Unknown Southern Land"), a vast continent stretching in parts into the tropics. The search for this great south land or Third World was a leading motive of explorers in the 16th and the early part of the 17th centuries. [4] In 1599, according to the account of Jacob le Maire, the Dutch Dirck Gerritsz Pomp observed mountainous land at latitude (64°). If so, these were the South Shetland Islands, and possibly the first European sighting of Antarctica (or offshore-lying islands belonging to it). Other accounts, however, do not note this observation, casting doubt on their accuracy. It has been argued that the Spaniard Gabriel de Castilla claimed to have sighted "snow-covered mountains" beyond the 64° S in 1603, but this claim is not generally recognized.

Quirós, in 1606, took possession for the king of Spain all of the lands he had discovered in Australia del Espiritu Santo (the New Hebrides) and those he would discover "even to the Pole". [4]

Francis Drake like Spanish explorers before him had speculated that there might be an open channel south of Tierra del Fuego. Indeed, when Schouten and Le Maire discovered the southern extremity of Tierra del Fuego and named it Cape Horn in 1615, they proved that the Tierra del Fuego archipelago was of small extent and not connected to the southern land. [4]

Finally, in 1642, Tasman showed that even New Holland (Australia) was separated by sea from any continuous southern continent. Voyagers round the Horn frequently met with contrary winds and were driven southward into snowy skies and ice-encumbered seas but, so far as can be ascertained, none of them before 1770 reached the Antarctic Circle, or knew it, if they did. [4]

The Dutch expedition to Valdivia of 1643 intended to round Cape Horn sailing through Le Maire Strait but strong winds made it instead drift south and east. [6] Northerly winds pushed the expedition as far south as 61°59 S where icebergs were abundant before a southerly wind that begun on April 7 allowed the fleet to advance west. [6] The small fleet led by Hendrik Brouwer managed to enter the Pacific Ocean sailing south of Isla de los Estados disproving earlier beliefs that it was part of Terra Australis. [6] [7] [8]

South of the Antarctic Convergence Edit

The visit to South Georgia by the English merchant Anthony de la Roché in 1675 was the first ever discovery of land south of the Antarctic Convergence. [9] [10] Soon after the voyage cartographers started to depict ‘Roché Island’, honouring the discoverer.

James Cook was aware of la Roché's discovery when surveying and mapping the island in 1775. [11]

Edmond Halley's voyage in HMS Paramour for magnetic investigations in the South Atlantic met the pack ice in 52° S in January 1700, but that latitude (he reached 140 mi off the north coast of South Georgia) was his farthest south. A determined effort on the part of the French naval officer Jean-Baptiste Charles Bouvet de Lozier to discover the "South Land" – described by a half legendary "sieur de Gonneyville" – resulted in the discovery of Bouvet Island in 54°10′ S, and in the navigation of 48° of longitude of ice-cumbered sea nearly in 55° S in 1739. [4]

In 1771, Yves Joseph Kerguelen sailed from France with instructions to proceed south from Mauritius in search of "a very large continent." He lighted upon a land in 50° S which he called South France, and believed to be the central mass of the southern continent. He was sent out again to complete the exploration of the new land, and found it to be only an inhospitable island which he renamed the Isle of Desolation, but which was ultimately named after him. [4]

The Antarctic Circle Edit

The obsession of the undiscovered continent culminated in the brain of Alexander Dalrymple, the brilliant and erratic hydrographer who was nominated by the Royal Society to command the Transit of Venus expedition to Tahiti in 1769. The command of the expedition was given by the admiralty to Captain James Cook. Sailing in 1772 with the Resolution, a vessel of 462 tons under his own command and the Adventure of 336 tons under Captain Tobias Furneaux, Cook first searched in vain for Bouvet Island, then sailed for 20 degrees of longitude to the westward in latitude 58° S, and then 30° eastward for the most part south of 60° S, a higher southern latitude than had ever been voluntarily entered before by any vessel. On 17 January 1773 the Antarctic Circle was crossed for the first time in history and the two ships reached 67° 15' S by 39° 35' E , where their course was stopped by ice. [4]

Cook then turned northward to look for French Southern and Antarctic Lands, of the discovery of which he had received news at Cape Town, but from the rough determination of his longitude by Kerguelen, Cook reached the assigned latitude 10° too far east and did not see it. He turned south again and was stopped by ice in 61° 52′ S by 95° E and continued eastward nearly on the parallel of 60° S to 147° E. On 16 March, the approaching winter drove him northward for rest to New Zealand and the tropical islands of the Pacific. In November 1773, Cook left New Zealand, having parted company with the Adventure, and reached 60° S by 177° W, whence he sailed eastward keeping as far south as the floating ice allowed. The Antarctic Circle was crossed on 20 December and Cook remained south of it for three days, being compelled after reaching 67° 31′ S to stand north again in 135° W. [4]

A long detour to 47° 50′ S served to show that there was no land connection between New Zealand and Tierra del Fuego. Turning south again, Cook crossed the Antarctic Circle for the third time at 109° 30′ W before his progress was once again blocked by ice four days later at 71° 10′ S by 106° 54′ W . This point, reached on 30 January 1774, was the farthest south attained in the 18th century. With a great detour to the east, almost to the coast of South America, the expedition regained Tahiti for refreshment. In November 1774, Cook started from New Zealand and crossed the South Pacific without sighting land between 53° and 57° S to Tierra del Fuego then, passing Cape Horn on 29 December, he rediscovered Roché Island renaming it Isle of Georgia, and discovered the South Sandwich Islands (named Sandwich Land by him), the only ice-clad land he had seen, before crossing the South Atlantic to the Cape of Good Hope between 55° and 60°. He thereby laid open the way for future Antarctic exploration by exploding the myth of a habitable southern continent. Cook's most southerly discovery of land lay on the temperate side of the 60th parallel, and he convinced himself that if land lay farther south it was practically inaccessible and of no economic value. [4]

First sighting Edit

The first land south of the parallel 60° south latitude was discovered by the Englishman William Smith, who sighted Livingston Island on 19 February 1819. He found some remnants and signs of the wreckage of the Spanish ship San Telmo, but to the date it is unknown if any surviving crew members of the San Telmo was landed there. [12] [13] [14] [15] [16] [17] A few months later Smith returned to explore the other islands of the South Shetlands archipelago, landed on King George Island, and claimed the new territories for Britain.

The first confirmed sighting of mainland Antarctica, on 27 January 1820, is attributed to the Russian expedition led by Fabian Gottlieb von Bellingshausen and Mikhail Lazarev, discovering an ice shelf at Princess Martha Coast that later became known as the Fimbul Ice Shelf. Bellingshausen and Lazarev became the first explorers to see and officially discover the land of the continent of Antarctica.

It is certain that the expedition, led by von Bellingshausen and Lazarev on the ships Vostok and Mirny, reached on 28 January 1820 a point within 32 km (20 mi) from Princess Martha Coast and recorded the sight of an ice shelf at 69°21′28″S 2°14′50″W  /  69.35778°S 2.24722°W  / -69.35778 -2.24722 [18] that became known as the Fimbul ice shelf. On 30 January 1820, Edward Bransfield sighted Trinity Peninsula, the northernmost point of the Antarctic mainland. Von Bellingshausen's expedition also discovered Peter I Island and Alexander I Island, the first islands to be discovered south of the circle.

Early exploration Edit

The first landing on the Antarctic mainland is thought to have been made by the American Captain John Davis, a sealer, who claimed to have set foot there on 7 February 1821, [19] though this is not accepted by all historians. [20]

In November 1820, Nathaniel Palmer, an American sealer looking for seal breeding grounds, using maps made by the Loper whaling family, sighted what is now known as the Antarctic Peninsula, located between 55 and 80 degrees west. In 1823, James Weddell, a British sealer, sailed into what is now known as the Weddell Sea. Until the twentieth century, most expeditions were for commercial purpose, to look for the prospects of seal and whale hunting. A piece of wood, from the South Shetland Islands, was the first fossil ever recorded from Antarctica, obtained during a private United States expedition during 1829–31, commanded by Captain Benjamin Pendleton. [21] [22] [23]

Charles Wilkes, as commander of a United States Navy expedition in 1840, [24] discovered what is now known as Wilkes Land, a section of the continent around 120 degrees East.

After the North Magnetic Pole was located in 1831, explorers and scientists began looking for the South Magnetic Pole. One of the explorers, James Clark Ross, a British naval officer, identified its approximate location, but was unable to reach it on his 4 year-expedition from 1839 to 1843. Commanding the British ships Erebus and Terror, he braved the pack ice and approached what is now known as the Ross Ice Shelf, a massive floating ice shelf over 100 feet (30 m) high. His expedition sailed eastward along the southern Antarctic coast discovering mountains which were since named after his ships: Mount Erebus, the most active volcano on Antarctica, and Mount Terror. [24]

The first documented landing on the mainland of East Antarctica was at Victoria Land by the American sealer Mercator Cooper on 26 January 1853. [25]

These explorers, despite their impressive contributions to South Polar exploration, were unable to penetrate the interior of the continent and, rather, formed a broken line of discovered lands along the coastline of Antarctica. Following the expedition South by the ships Erebus and Terror under James Clark Ross (January, 1841), he suggested that there were no scientific discoveries, or 'problems', worth exploration in the far South. [26] What followed is what historian H.R. Mill called 'the age of averted interest' [26] and in the following twenty years after Ross' return, there was a general lull internationally in Antarctic exploration. [26]

During this period the Antarctic continent became the focus of an international effort that resulted in intensive scientific and geographical exploration and in which 17 major Antarctic expeditions were launched from ten countries. [28]

Origins Edit

An important precursor to the Heroic Age of Antarctic exploration was the Dundee Antarctic Expedition of 1892-93 in which four Dundee whaling ships travelled south to the Antarctic in search of whales instead of their usual Arctic route. The expedition was accompanied by several naturalists (including Williams Speirs Bruce) and an artist, William Gordon Burn Murdoch. The publications (both scientific and popular) and exhibitions that resulted did much to reignite public interest in the Antarctic. The performance of the whaling ships was also crucial in the decision to build the RRS Discovery in Dundee. [29]

Following on from that expedition, the specific impetus for the Heroic Age of Antarctic Exploration was a lecture given by Dr John Murray entitled "The Renewal of Antarctic Exploration", given to the Royal Geographical Society in London, 27 November 1893. [30] Murray advocated that research into the Antarctic should be organised to "resolve the outstanding geographical questions still posed in the south". [31] Furthermore, the Royal Geographical Society instated an Antarctic Committee shortly prior to this, in 1887, which successfully encouraged many whalers to explore the Southern regions of the world and laid the groundwork for the lecture given by Murray. [32]

The Norwegian ship Antarctic was put ashore at Cape Adare, on 24 January 1895. [33]

In August 1895 the Sixth International Geographical Congress in London passed a general resolution calling on scientific societies throughout the world to promote the cause of Antarctic exploration "in whatever ways seem to them most effective". [34] Such work would "bring additions to almost every branch of science". [34] The Congress had been addressed by the Norwegian Carsten Borchgrevink, who had just returned from a whaling expedition during which he had become one of the first to set foot on the Antarctic mainland. [4] During his address, Borchgrevink outlined plans for a full-scale pioneering Antarctic expedition, to be based at Cape Adare. [35] [36]

The Heroic Age was inaugurated by an expedition launched by the Belgian Geographical Society in 1897 Borchgrevink followed a year later with a privately sponsored British expedition. [37] (Some histories consider the Discovery expedition, which departed in 1901, as the first proper expedition of the Heroic Age. [38] )

The Belgian Antarctic Expedition was led by Belgian Adrian de Gerlache. In 1898, they became the first men to spend winter on Antarctica, when their ship Belgica became trapped in the ice. They became stuck on 28 February 1898, and only managed to get out of the ice on 14 March 1899.

During their forced stay, several men lost their sanity, not only because of the Antarctic winter night and the endured hardship, but also because of the language problems between the different nationalities. This was the first expedition to overwinter within the Antarctic Circle, [39] [40] and they visited the South Shetland Islands. [41]

Early British expeditions Edit

The Southern Cross Expedition began in 1898 and lasted for two years. This was the first expedition to overwinter on the Antarctic mainland (Cape Adare) and was the first to make use of dogs and sledges. It made the first ascent of The Great Ice Barrier, (The Great Ice Barrier later became formally known as the Ross Ice Shelf). The expedition set a Farthest South record at 78°30'S. It also calculated the location of the South Magnetic Pole. [42] [43]

The Discovery Expedition was then launched, from 1901 to 1904 and was led by Robert Falcon Scott. It made the first ascent of the Western Mountains in Victoria Land, and discovered the polar plateau. Its southern journey set a new Farthest South record, 82°17'S. Many other geographical features were discovered, mapped and named. This was the first of several expeditions based in McMurdo Sound. [44] [45] [46]

A year later, the Scottish National Antarctic Expedition was launched, headed by William Speirs Bruce. 'Ormond House' was established as a meteorological observatory on Laurie Island in the South Orkneys and was the first permanent base in Antarctica. The Weddell Sea was penetrated to 74°01'S, and the coastline of Coats Land was discovered, defining the sea's eastern limits. [47] [48] [49]

Ernest Shackleton, who had been a member of Scott's expedition, organized and led the Nimrod Expedition from 1907 to 1909. The expedition's primary objective was of reaching the South Pole. Based in McMurdo Sound, the expedition pioneered the Beardmore Glacier route to the South Pole, and the (limited) use of motorised transport. Its southern march reached 88°23'S, a new Farthest South record 97 geographical miles from the Pole before having to turn back. During the expedition, Shackleton was the first to reach the polar plateau. Parties led by T. W. Edgeworth David also became the first to climb Mount Erebus and to reach the South Magnetic Pole. [50] [51] [52]

Expeditions from other countries Edit

The First German Antarctic Expedition was sent to investigate eastern Antarctica in 1901. It discovered the coast of Kaiser Wilhelm II Land, and Mount Gauss. The expedition's ship became trapped in ice, however, which prevented more extensive exploration. [53] [54] [55]

The Swedish Antarctic Expedition, operating at the same time worked in the east coastal area of Graham Land, and was marooned on Snow Hill Island and Paulet Island in the Weddell Sea, after the sinking of its expedition ship. It was rescued by the Argentinian naval vessel Uruguay. [56] [57] [58]

The French organized their first expedition in 1903 under the leadership of Jean-Baptiste Charcot. Originally intended as a relief expedition for the stranded Nordenskiöld party, the main work of this expedition was the mapping and charting of islands and the western coasts of Graham Land, on the Antarctic peninsula. A section of the coast was explored, and named Loubet Land after the President of France. [59] [60] [61]

A follow up trip was organized from 1908 to 1910 which continued the earlier work of the French expedition with a general exploration of the Bellingshausen Sea, and the discovery of islands and other features, including Marguerite Bay, Charcot Island, Renaud Island, Mikkelsen Bay, Rothschild Island. [62]

Race to the Pole Edit

The prize of the Heroic age was to reach the South Pole. Two expeditions set off in 1910 to attain this goal a party led by Norwegian polar explorer Roald Amundsen from the ship Fram and Robert Falcon Scott's British group from the Terra Nova.

Amundsen succeeded in reaching the Pole on 14 December 1911 using a route from the Bay of Whales to the polar plateau via the Axel Heiberg Glacier. [63] [64] [65]

Scott and his four companions reached the South Pole via the Beardmore route on 17 January 1912, 33 days after Amundsen. All five died on the return journey from the Pole, through a combination of starvation and cold. [66] The Amundsen–Scott South Pole Station was later named after these two men.

Further expeditions Edit

The Australasian Antarctic Expedition took place between 1911–1914 and was led by Sir Douglas Mawson. It concentrated on the stretch of Antarctic coastline between Cape Adare and Mount Gauss, carrying out mapping and survey work on coastal and inland territories.

Discoveries included Commonwealth Bay, Ninnis Glacier, Mertz Glacier, and Queen Mary Land. Major accomplishments were made in geology, glaciology and terrestrial biology. [67]

The Imperial Trans-Antarctic Expedition of 1914–1917 was led by Ernest Shackleton and set out to cross the continent via the South pole. However, their ship, the Endurance, was trapped and crushed by pack ice in the Weddell Sea before they were able to land. The expedition members survived after a journey on sledges over pack ice, a prolonged drift on an ice-floe, and a voyage in three small boats to Elephant Island. Then Shackleton and five others crossed the Southern Ocean in an open boat called James Caird and made the first crossing of South Georgia to raise the alarm at the whaling station Grytviken. [68]

A related component of the Trans-Antarctic Expedition was the Ross Sea party, led by Aeneas Mackintosh. Its objective was to lay depots across the Great Ice Barrier, in order to supply Shackleton's party crossing from the Weddell Sea. All the required depots were laid, but in the process three men, including the leader Mackintosh, lost their lives. [69]

Shackleton's last expedition and the one that brought the 'Heroic Age' to a close, was the Shackleton–Rowett Expedition from 1921 to 1922 on board the ship Quest. Its vaguely defined objectives included coastal mapping, a possible continental circumnavigation, the investigation of sub-Antarctic islands, and oceanographic work. After Shackleton's death on 5 January 1922, Quest completed a shortened programme before returning home. [70]

By air Edit

After Shackleton's last expedition, there was a hiatus in Antarctic exploration for about seven years. From 1929, aircraft and mechanized transportation were increasingly used, earning this period the sobriquet of the 'Mechanical Age'. Hubert Wilkins first visited Antarctica in 1921–1922 as an ornithologist attached to the Shackleton-Rowett Expedition. From 1927, Wilkins and pilot Carl Ben Eielson began exploring the Arctic by aircraft. [71]

On 15 April 1928, only a year after Charles Lindbergh's flight across the Atlantic, Wilkins and Eielson made a trans-Arctic crossing from Point Barrow, Alaska, to Spitsbergen, arriving about 20 hours later on 16 April, touching along the way at Grant Land on Ellesmere Island. [72] For this feat and his prior work, Wilkins was knighted.

With financial backing from William Randolph Hearst, Wilkins returned to the South Pole and flew over Antarctica in the San Francisco. He named the island of Hearst Land after his sponsor.

US Navy Rear Admiral Richard Evelyn Byrd led five expeditions to Antarctica during the 1930s, 1940s, and 1950s. He overflew the South Pole with pilot Bernt Balchen on 28 and 29 November 1929, to match his overflight of the North Pole in 1926. Byrd's explorations had science as a major objective and extensively used the aircraft to explore the continent.

Captain Finn Ronne, Byrd's executive officer, returned to Antarctica with his own expedition in 1947–1948, with Navy support, three planes, and dogs. Ronne disproved the notion that the continent was divided in two and established that East and West Antarctica was one single continent, i.e. that the Weddell Sea and the Ross Sea are not connected. [73] The expedition explored and mapped large parts of Palmer Land and the Weddell Sea coastline, and identified the Ronne Ice Shelf, named by Ronne after his wife Edith Ronne. [74] Ronne covered 3,600 miles by ski and dog sled—more than any other explorer in history. [75]

Overland crossing Edit

The 1955–58 Commonwealth Trans-Antarctic Expedition successfully completed the first overland crossing of Antarctica, via the South Pole. Although supported by the British and other Commonwealth governments, most of the funding came from corporate and individual donations.

It was headed by British explorer Dr Vivian Fuchs, with New Zealander Sir Edmund Hillary leading the New Zealand Ross Sea Support team. After spending the winter of 1957 at Shackleton Base, Fuchs finally set out on the transcontinental journey in November 1957, with a twelve-man team travelling in six vehicles three Sno-Cats, two Weasels and one specially adapted Muskeg tractor. En route, the team were also tasked with carrying out scientific research including seismic soundings and gravimetric readings.

In parallel Hillary's team had set up Scott Base – which was to be Fuchs' final destination – on the opposite side of the continent at McMurdo Sound on the Ross Sea. Using three converted Massey Ferguson TE20 tractors [76] and one Weasel (abandoned part-way), Hillary and his three men (Ron Balham, Peter Mulgrew and Murray Ellis), were responsible for route-finding and laying a line of supply depots up the Skelton Glacier and across the Polar Plateau on towards the South Pole, for the use of Fuchs on the final leg of his journey. Other members of Hillary's team carried out geological surveys around the Ross Sea and Victoria Land areas.

Hillary's party reached the South Pole on 3 January 1958, and was just the third (preceded by Amundsen in 1911 and Scott in 1912) to reach the Pole overland. Fuchs' team reached the Pole from the opposite direction on 19 January 1958, where they met up with Hillary. Fuchs then continued overland, following the route that Hillary had laid and on 2 March succeeded in reaching Scott Base, completing the first overland crossing of the continent by land via the South Pole. [24]

British claims Edit

The United Kingdom reasserted sovereignty over the Falkland Islands in the far South Atlantic in 1833 and maintained a continuous presence there. In 1908, the British government extended its territorial claim by declaring sovereignty over "South Georgia, the South Orkneys, the South Shetlands, and the Sandwich Islands, and Graham's Land, situated in the South Atlantic Ocean and on the Antarctic continent to the south of the 50th parallel of south latitude, and lying between the 20th and the 80th degrees of west longitude". [77] All these territories were administered as Falkland Islands Dependencies from Stanley by the Governor of the Falkland Islands. The motivation for this declaration lay in the need for regulating and taxing the whaling industry effectively. Commercial operators would hunt whales in areas outside of the official boundaries of the Falkland Islands and its dependencies and there was a need to close this loophole.

In 1917, the wording of the claim was modified, so as to, among other things, unambiguously include all the territory in the sector stretching to the South Pole (thus encompassing all of the present-day British Antarctic Territory). The new claim covered "all islands and territories whatsoever between the 20th degree of west longitude and the 50th degree of west longitude which are situated south of the 50th parallel of south latitude and all islands and territories whatsoever between the 50th degree of west longitude and the 80th degree of west longitude which are situated south of the 58th parallel of south latitude". [77]

Under the ambition of Leopold Amery, the Under-Secretary of State for the Colonies, Britain attempted to incorporate the entire continent into the Empire. In a memorandum to the governor-generals for Australia and New Zealand, he wrote that 'with the exception of Chile and Argentina and some barren islands belonging to France. it is desirable that the whole of the Antarctic should ultimately be included in the British Empire.'

The first step was taken on 30 July 1923, when the British government passed an Order in Council under the British Settlements Act 1887, defining the new borders for the Ross Dependency - "that part of His Majesty's Dominions in the Antarctic Seas, which comprises all the islands and territories between the 160th degree of East Longitude and the 150th degree of West Longitude which are situated south of the 60th degree of South Latitude shall be named the Ross Dependency."

The Order in Council then went on to appoint the Governor-General and Commander-in Chief of New Zealand as the Governor of the territory. [78]

In 1930, the United Kingdom claimed Enderby Land. In 1933, a British imperial order transferred territory south of 60° S and between meridians 160° E and 45° E to Australia as the Australian Antarctic Territory. [79] [80]

Following the passing of the Statute of Westminster in 1931, the government of the United Kingdom relinquished all control over the government of New Zealand and Australia. This however had no bearing on the obligations of the Governor-General of both countries in their capacity as Governor of the Antarctic territories.

Other European claims Edit

Meanwhile, alarmed by these unilateral declarations, the French government laid claim to a strip of the continent in 1924. The basis for their claim to Adélie Land lay on the discovery of the coastline in 1840 by the French explorer Jules Dumont d'Urville, who named it after his wife, Adèle. [81] The British eventually decided to recognize this claim and the border between Adélie Land and Australian Antarctic Territory was fixed definitively in 1938. [82]

These developments also concerned Norwegian whaling interests, who wished to avoid the British taxation of whaling stations in the Antarctic and were concerned that they would be commercially excluded from the continent. The whale-ship owner Lars Christensen financed several expeditions to the Antarctic with the view to claim land for Norway and establish stations on Norwegian territory to gain better privileges. [83] The first expedition, led by Nils Larsen and Ola Olstad, landed on Peter I Island in 1929 and claimed the island for Norway. On 6 March 1931, a Norwegian royal proclamation declared the island under Norwegian sovereignty [83] and on 23 March 1933 the island was declared a dependency. [84]

The 1929 expedition led by Hjalmar Riiser-Larsen and Finn Lützow-Holm named the continental land mass near the island as Queen Maud Land, named after the Norwegian queen Maud of Wales. [85] The territory was explored further during the Norvegia expedition of 1930–31. [86] Negotiations with the British government in 1938 resulted in the western border of Queen Maud Land being set at 20°W. [86]

Norway's claim was disputed by Nazi Germany, [87] which in 1938 dispatched the German Antarctic Expedition, led by Alfred Ritscher, to fly over as much of it as possible. [86] The ship Schwabenland reached the pack ice off Antarctica on 19 January 1939. [88] During the expedition, an area of about 350,000 square kilometres (140,000 sq mi) was photographed from the air by Ritscher, [89] who dropped darts inscribed with swastikas every 26 kilometres (16 mi). Germany eventually attempted to claim the territory surveyed by Ritscher under the name New Swabia, but lost any claim to the land following its defeat in the Second World War. [87]

On 14 January 1939, five days prior to the German arrival, Queen Maud Land was annexed by Norway, [85] after a royal decree announced that the land bordering the Falkland Islands Dependencies in the west and the Australian Antarctic Dependency in the east was to be brought under Norwegian sovereignty. [86] The primary basis for the annexation was to secure the Norwegian whaling industry's access to the region. [85] [90] In 1948, Norway and the United Kingdom agreed to limit Queen Maud Land to from 20°W to 45°E, and that the Bruce Coast and Coats Land were to be incorporated into Norwegian territory. [86]

South American involvement Edit

This encroachment of foreign powers was a matter of immense disquiet to the nearby South American countries, Argentina and Chile. Taking advantage of a European continent plunged into turmoil with the onset of the Second World War, Chile's president, Pedro Aguirre Cerda declared the establishment of a Chilean Antarctic Territory in areas already claimed by Britain.

Argentina had an even longer history of involvement in the Continent. Already in 1904 the Argentine government began a permanent occupation in the area with the purchase of a meteorological station on Laurie Island established in 1903 by Dr William S. Bruce's Scottish National Antarctic Expedition. Bruce offered to transfer the station and instruments for the sum of 5.000 pesos, on the condition that the government committed itself to the continuation of the scientific mission. [91] British officer William Haggard also sent a note to the Argentine Foreign Minister, Jose Terry, ratifying the terms of Bruce proposition. [91]

In 1906, Argentina communicated to the international community the establishment of a permanent base on South Orkney Islands. However, Haggard responded by reminding Argentina that the South Orkneys were British. The British position was that Argentine personnel was granted permission only for the period of one year. The Argentine government entered into negotiations with the British in 1913 over the possible transfer of the island. Although these talks were unsuccessful, Argentina attempted to unilaterally establish their sovereignty with the erection of markers, national flags and other symbols. [92] Finally, with British attention elsewhere, Argentina declared the establishment of Argentine Antarctica in 1943, claiming territory that overlapped with British ( 20°W to 80°W) and the earlier Chilean (53°W to 90°W) claims.

In response to this and earlier German explorations, the British Admiralty and Colonial Office launched Operation Tabarin in 1943 to reassert British territorial claims against Argentine and Chilean incursion and establish a permanent British presence in the Antarctic. [93] The move was also motivated by concerns within the Foreign Office about the direction of United States post-war activity in the region.

A suitable cover story was the need to deny use of the area to the enemy. The Kriegsmarine was known to use remote islands as rendezvous points and as shelters for commerce raiders, U-boats and supply ships. Also, in 1941, there existed a fear that Japan might attempt to seize the Falkland Islands, either as a base or to hand them over to Argentina, thus gaining political advantage for the Axis and denying their use to Britain.

In 1943, British personnel from HMS Carnarvon Castle [94] removed Argentine flags from Deception Island. The expedition was led by Lieutenant James Marr and left the Falkland Islands in two ships, HMS William Scoresby (a minesweeping trawler) and Fitzroy, on Saturday 29 January 1944.

Bases were established during February near the abandoned Norwegian whaling station on Deception Island, where the Union Flag was hoisted in place of Argentine flags, and at Port Lockroy (on February 11) on the coast of Graham Land. A further base was founded at Hope Bay on 13 February 1945, after a failed attempt to unload stores on 7 February 1944. Symbols of British sovereignty, including post offices, signposts and plaques were also constructed and postage stamps were issued.

Operation Tabarin provoked Chile to organize its First Chilean Antarctic Expedition in 1947–48, where the Chilean president Gabriel González Videla personally inaugurated one of its bases. [95]

Following the end of the war in 1945, the British bases were handed over to civilian members of the newly created Falkland Islands Dependencies Survey (subsequently the British Antarctic Survey) the first such national scientific body to be established in Antarctica.

Post war developments Edit

Friction between Britain and the Latin American states continued into the post war period. Royal Navy warships were despatched in 1948 to prevent naval incursions and in 1952, an Argentine shore party at Hope Bay (the British Base "D", established there in 1945, came up against the Argentine Esperanza Base, est. 1952) fired a machine gun over the heads of a British Antarctic Survey team unloading supplies from the John Biscoe. The Argentines later extended a diplomatic apology, saying that there had been a misunderstanding and that the Argentine military commander on the ground had exceeded his authority.

The United States became politically interested in the Antarctic continent before and during WWII. The United States Antarctic Service Expedition, from 1939 to 1941, was sponsored by the government with additional support came from donations and gifts by private citizens, corporations and institutions. The objectives of the Expedition, outlined by President Franklin D. Roosevelt, was to establish two bases: East Base, in the vicinity of Charcot Island, and West Base, in the vicinity of King Edward VII Land. After operating successfully for two years, but with international tensions on the rise, it was considered wise to evacuate the two bases. [96]

However, immediately after the war, American interest was rekindled with an explicitly geopolitical motive. Operation Highjump, from 1946 to 1947 was organized by Rear Admiral Richard E. Byrd Jr. and included 4,700 men, 13 ships, and multiple aircraft. The primary mission of Operation Highjump was to establish the Antarctic research base Little America IV, [97] for the purpose of training personnel and testing equipment in frigid conditions and amplifying existing stores of knowledge of hydrographic, geographic, geological, meteorological and electromagnetic propagation conditions in the area. The mission was also aimed at consolidating and extending United States sovereignty over the largest practicable area of the Antarctic continent, although this was publicly denied as a goal even before the expedition ended.

Towards an international treaty Edit

Meanwhile, in an attempt at ending the impasse, Britain submitted an application to the International Court of Justice in 1955 to adjudicate between the territorial claims of Britain, Argentina and Chile. This proposal failed, as both Latin American countries rejected submitting to an international arbitration procedure. [98]

Negotiations towards the establishment of an international condominium over the continent first began in 1948, involving the 7 claimant powers (Britain, Australia, New Zealand, France, Norway, Chile and Argentina) and the US. This attempt was aimed at excluding the Soviet Union from the affairs of the continent and rapidly fell apart when the USSR declared an interest in the region, refused to recognize any claims of sovereignty and reserved the right to make its own claims in 1950. [98]

An important impetus toward the formation of the Antarctic Treaty System in 1959, was the International Geophysical Year, 1957–1958. This year of international scientific cooperation triggered an 18-month period of intense Antarctic science. More than 70 existing national scientific organizations then formed IGY committees, and participated in the cooperative effort. The British established Halley Research Station in 1956 by an expedition from the Royal Society. Sir Vivian Fuchs headed the Commonwealth Trans-Antarctic Expedition, which completed the first overland crossing of Antarctica in 1958. In Japan, the Japan Maritime Safety Agency offered ice breaker Sōya as the South Pole observation ship and Showa Station was built as the first Japanese observation base on Antarctica.

France contributed with Dumont d'Urville Station and Charcot Station in Adélie Land. The ship Commandant Charcot of the French Navy spent nine months of 1949/50 at the coast of Adelie Land, performing ionospheric soundings. [99] The US erected the Amundsen–Scott South Pole Station as the first permanent structure directly over the South Pole in January 1957. [100]

Finally, to prevent the possibility of military conflict in the region, the United States, United Kingdom, the Soviet Union and 9 other countries with significant interests negotiated and signed the Antarctic Treaty in 1959. The treaty entered into force in 1961 and sets aside Antarctica as a scientific preserve, established freedom of scientific investigation and banned military activity on that continent. The treaty was the first arms control agreement established during the Cold War. [101]

In May 1965, the American physicist Carl R. Disch went missing during the course of his routine research near Byrd Station, Antarctica. His body was never found. [102]

A baby, named Emilio Marcos de Palma, was born near Hope Bay on 7 January 1978, becoming the first baby born on the continent. He also was born farther south than anyone in history. [103]

On 28 November 1979, an Air New Zealand DC-10 on a sightseeing trip crashed into Mount Erebus on Ross Island, killing all 257 people on board. [104]

In 1991 a convention among member nations of the Antarctic Treaty on how to regulate mining and drilling was proposed. Australian Prime Minister Bob Hawke and French Prime Minister Michel Rocard led a response to this convention that resulted in the adoption of the Protocol on Environmental Protection to the Antarctic Treaty, now known as the Madrid Protocol. All mineral extraction was banned for 50 years and the Antarctic was set aside as a "natural reserve, devoted to peace and science". [105]

Børge Ousland, a Norwegian explorer, finished the first unassisted Antarctic solo crossing on 18 January 1997.

On 23 November 2007, the MV Explorer struck an iceberg and sank, but all on board were rescued by nearby ships, including a passing Norwegian cruise ship, the MS Nordnorge.

Women were originally kept from exploring Antarctica until well into the 1950s. A few pioneering women visited the Antarctic land and waters prior to the 1950s and many women requested to go on early expeditions, but were turned away. [106] Early pioneers such as Louise Séguin [107] and Ingrid Christensen were some of the first women to see Antarctic waters. [108] Christensen was the first woman to set foot on the mainland of Antarctica. [108] The first women to have any fanfare about their Antarctic journeys were Caroline Mikkelsen who set foot on an island of Antarctica in 1935, [109] and Jackie Ronne and Jennie Darlington who were the first women to over-winter in Antarctica in 1947. [110] The first woman scientist to work in Antarctica was Maria Klenova in 1956. [111] Silvia Morella de Palma was the first woman to give birth in Antarctica, delivering 3.4 kg (7 lb 8 oz) Emilio Palma at the Argentine Esperanza base 7 January 1978.

Women faced legal barriers and sexism that prevented most from visiting Antarctica and doing research until the late 1960s. The United States Congress banned American women from traveling to Antarctica until 1969. [112] Women were often excluded because it was thought that they could not handle the extreme temperatures or crisis situations. [113] The first woman from the British Antarctic Survey to go to Antarctica was Janet Thomson in 1983 who described the ban on women as a "rather improper segregation." [114] [115]

Once women were allowed in Antarctica, they still had to fight against sexism and sexual harassment. [116] [117] However, a tipping point was reached in the mid 1990s when it became the new normal that women were part of Antarctic life. [118] Women began to see a change as more and more women began working and researching in Antarctica. [119]


The Phoenicians - Master Mariners

Driven by their desire for trade and the acquisition of such commodities as silver from Spain, gold from Africa, and tin from the Scilly Isles, the Phoenicians sailed far and wide, even beyond the Mediterranean's traditional safe limits of the Pillars of Hercules and into the Atlantic. They were credited with many important nautical inventions and firmly established a reputation as the greatest mariners in the ancient world. Phoenician ships were represented in the art of their neighbours, and their seamanship is praised above all other by such ancient writers as Homer and Herodotus. If any nation could claim to be the masters of the seas, it was the Phoenicians.

Leaving the Homeland

The Phoenicians became sailors in the first place because of the topography of their homeland, the narrow mountainous strip of land on the coast of the Levant. Travelling between settlements, usually located on rocky peninsulas, was much easier by sea, especially when carrying such cumbersome cargo as cedar wood logs for which the Phoenicians were famed. It was thanks to the very same wood the Phoenicians were never short of the necessary raw materials to build their ships. The Phoenicians also preferred the security of small islets just off the coast, the classic example being the great city of Tyre, so that ships were the most practical means of transport.

Advertisement

Hemmed in by mountains, then, when the time came, perhaps from the 12th century BCE, the natural direction of Phoenician expansion was not inland but the sea. As a result of this search for new resources such as gold and tin, the Phoenicians became accomplished sailors, creating an unprecedented trade network which went from Cyprus, Rhodes, the Aegean islands, Egypt, Sicily, Malta, Sardinia, central Italy, France, North Africa, Ibiza, Spain and beyond even the Pillars of Hercules and the bounds of the Mediterranean. In time, this network transformed into an empire of colonies so that the Phoenicians criss-crossed the seas and gained the confidence to reach such far-flung places as ancient Britain and the Atlantic coast of Africa.

Phoenician Ships

The Phoenicians were famed in antiquity for their ship-building skills, and they were credited with inventing the keel, the battering ram on the bow, and caulking between planks. From Assyrian relief carvings at Nineveh and Khorsabad, and descriptions in texts such as the book of Ezekial in the Bible we know that the Phoenicians had three types of ship, all shallow-keeled. Warships had a convex stern and were propelled by a large single-masted square sail and two banks of oars (a bireme), had a deck, and were fitted with a ram low on the bow.

Advertisement

The second ship type was for transport and trade purposes. These were similar to the first type but, with wide, big-bellied hulls, they were much heavier. They perhaps had higher sides too in order to permit the stacking of cargo on deck as well as below, and they had both a convex stern and bow. Their cargo capacity was somewhere in the region of 450 tons. A fleet might consist of up to 50 cargo vessels, and such fleets are depicted in reliefs being escorted by a number of warships.

A third type of vessel, also for trade use, was much smaller than the other two, had a horse-head at the bow and only one bank of oars. Due to its size, this vessel was only used for coastal fishing and short trips. No Phoenician ship has been recovered intact by maritime archaeologists but judging by the pictorial evidence the ships would have been difficult to handle. It is also worth noting that the more oarsmen a ship had then the less room there was for cargo. Greater manoeuvrability was, therefore, achieved by adjusting the sail when necessary and the use of a double sailing oar.

Sign up for our free weekly email newsletter!

Ancient ships were far from easy to handle but in antiquity the Phoenicians were widely known as the best sailors around. Herodotus describes one episode during the build up to the second Persian invasion of Greece in 480 BCE led by Xerxes. The Persian king wanted to put his multi-national fleet through their paces and so organized a sailing race, which the sailors from Sidon won. Herodotus also mentions that Xerxes always made sure to travel on a Phoenician ship whenever he had to go anywhere by sea.

Navigation

The Phoenicians did not have the compass or any other navigational instrument, and so they relied on natural features on coastlines, the stars, and dead-reckoning to guide their way and reach their destination. The most important star to them was the Pole Star of the Ursa Minor constellation and, by way of a compliment to their sea-faring skills, the Greek name for this group was actually Phoenike or 'Phoenician'. Some maps of coastal stretches are known to have existed but were unlikely to have been used during a voyage. Rather, navigation was achieved through the position of the stars, sun, landmarks, direction of the winds, and the experience of the captain of tides, currents and winds on the particular route being taken. Close to shore, Herodotus mentions the use of sounding leads to measure the sea depth, and we know that Phoenician ships had a crow's nest for greater visibility.

Advertisement

Historians long considered that the Phoenicians sailed only during the day-time as they had to keep close to the shoreline and within sight of landmarks at night they, therefore, had to beach or anchor their ships and this explained the proximity of some Phoenician colonies, a day's sailing distance from each other. This simplistic view has been revised in recent years. First and foremost, the often mountainous coastline of the Mediterranean means that one can sail a great distance from land and still keep high landmarks in sight, a strategy still used by many local fishermen today. Indeed, the areas of sea where it is not possible to sight land of some sort are remarkably few in the Mediterranean, and these are places ancient mariners would have had no interest in crossing anyway. In addition, it can actually be more dangerous sailing close to a coast than out to sea where there are no rocks or unpredictable currents.

Neither does the traditional view take into account that the Phoenicians used astronomical observations at night. Further, many Phoenician settlements were either much closer than a day's sailing distance or much further, for example, Ibiza is 65 straight miles from Iberia. The same can be said for Sardinia and Sicily, and there is also evidence that the Phoenicians made use of even more remote smaller islands as stopping points. It seems reasonable to assume, then, that Phoenician navigators, at least in fine weather, would have chosen the shortest direct route between two points and not necessarily hugged the coast or stopped each night as much as once thought. The non-stop voyages described in both Hesiod and Homer would seem to deserve more credit as to their accuracy. It is true that in foggy or rainy weather landmarks and stars become useless but that is probably why the Phoenicians restricted their sailing season to the period between late spring and early autumn, when the Mediterranean climate is remarkably stable.

Sea Routes

Both Herodotus and Thucydides agree that the average speed of an ancient vessel was around 6 miles per hour, and therefore, taking into account stops for bad weather, rest etc., it would have taken, for example, 15 days to sail (and sometimes row) from Greece to Sicily. Colaios sailed from Samos to Gadir (in southern Spain), a distance of 2,000 miles, in the 7th century BCE, and that would have taken around 60 days. Long voyages, then, would frequently have required winter stop-overs and continuing in the next sailing season. Herodotus mentions this fact, even describing how the mariners were able to grow their own wheat as they waited. So, from one end of the Phoenician world to the other - Tyre to Gadir (over 1,600 miles) - might have taken 90 days or a full sailing season the ship would have unloaded and re-loaded cargo and made the journey back the next year.

Advertisement

The actual routes taken by the Phoenicians are much debated, but if we assume the currents of the Mediterranean have not changed since antiquity, then it seems likely that ancient mariners took advantage of the long-distance currents used by sailors today. The route west, then, would probably have been via Cyprus, the coast of Anatolia, Rhodes, Malta, Sicily, Sardinia, Ibiza, and along the coast of southern Spain to silver-rich Gadir. The homeward journey would have benefitted from the current which sweeps back right through the centre of the Mediterranean. This would give two possible routes: to Ibiza and then Sardinia, or to Carthage on the North African coast and then to either Sardinia or direct to Malta, and then Phoenicia. It is no surprise that at each of these vital strategic stopping points the Phoenicians created colonies which, in effect, cut out, at least for a few centuries, competing trading cultures such as the Greeks.

Famous Voyages

According to Herodotus, the Phoenicians managed to circumnavigate Africa in a voyage in c. 600 BCE sponsored by the Egyptian pharaoh Necho. Starting from the Red Sea, they sailed westwards in a journey that took three years. The sailors of Phoenicia's most successful colony Carthage were said to have sailed to ancient Britain in an expedition led by Himilco in c. 450 BCE. Another famous Carthaginian voyage, this time by Hanno in c. 425 BCE, reached the Atlantic coast of Africa as far down as modern Cameroon or Gabon. The voyage, whose purpose was to found new colonies and find new sources of valuable commodities (especially gold), is recorded on a stele from the temple of Baal Hammon at Carthage. In the tale, Hanno describes meeting savage tribes, volcanoes, and exotic animals such as gorillas.

Advertisement

The Phoenicians were not limited to the Mediterranean and the Atlantic, they also sailed down the Red Sea and possibly the Indian Ocean too. The book of I Kings in the Bible describes a Phoenician expedition during the 10th century BCE to a new land called Ophir in order to acquire gold, silver, ivory, and gems. The location of Ophir is not known but is variously considered to be in the Sudan, Somalia, Yemen, or even an island in the Indian Ocean. The ships of this fleet were built at Eziongeber on the Red Sea coast and funded by King Solomon. The great distance covered is suggested by the description that the expedition was repeated only every three years.

The ancient historian Diodorus claimed that the Phoenicians reached the Atlantic islands of Madeira, the Canary Islands, and the Azores. There is, though, no archaeological evidence of direct Phoenician contact, only the discovery in 1749 CE of eight Carthaginian coins dating to the 3rd century BCE. Just how they got there can only be speculated upon.


Contents

Earth's magnetic field serves to deflect most of the solar wind, whose charged particles would otherwise strip away the ozone layer that protects the Earth from harmful ultraviolet radiation. [4] One stripping mechanism is for gas to be caught in bubbles of magnetic field, which are ripped off by solar winds. [5] Calculations of the loss of carbon dioxide from the atmosphere of Mars, resulting from scavenging of ions by the solar wind, indicate that the dissipation of the magnetic field of Mars caused a near total loss of its atmosphere. [6] [7]

The study of the past magnetic field of the Earth is known as paleomagnetism. [8] The polarity of the Earth's magnetic field is recorded in igneous rocks, and reversals of the field are thus detectable as "stripes" centered on mid-ocean ridges where the sea floor is spreading, while the stability of the geomagnetic poles between reversals has allowed paleomagnetism to track the past motion of continents. Reversals also provide the basis for magnetostratigraphy, a way of dating rocks and sediments. [9] The field also magnetizes the crust, and magnetic anomalies can be used to search for deposits of metal ores. [10]

Humans have used compasses for direction finding since the 11th century A.D. and for navigation since the 12th century. [11] Although the magnetic declination does shift with time, this wandering is slow enough that a simple compass can remain useful for navigation. Using magnetoreception various other organisms, ranging from some types of bacteria to pigeons, use the Earth's magnetic field for orientation and navigation.

At any location, the Earth's magnetic field can be represented by a three-dimensional vector. A typical procedure for measuring its direction is to use a compass to determine the direction of magnetic North. Its angle relative to true North is the declination ( D ) or variation. Facing magnetic North, the angle the field makes with the horizontal is the inclination ( I ) or magnetic dip. The intensity ( F ) of the field is proportional to the force it exerts on a magnet. Another common representation is in X (North), Y (East) and Z (Down) coordinates. [12]

Intensity Edit

The intensity of the field is often measured in gauss (G), but is generally reported in nanoteslas (nT), with 1 G = 100,000 nT. A nanotesla is also referred to as a gamma (γ). The Earth's field ranges between approximately 25,000 and 65,000 nT (0.25–0.65 G). [13] By comparison, a strong refrigerator magnet has a field of about 10,000,000 nanoteslas (100 G). [14]

A map of intensity contours is called an isodynamic chart. As the World Magnetic Model shows, the intensity tends to decrease from the poles to the equator. A minimum intensity occurs in the South Atlantic Anomaly over South America while there are maxima over northern Canada, Siberia, and the coast of Antarctica south of Australia. [15]

Inclination Edit

The inclination is given by an angle that can assume values between -90° (up) to 90° (down). In the northern hemisphere, the field points downwards. It is straight down at the North Magnetic Pole and rotates upwards as the latitude decreases until it is horizontal (0°) at the magnetic equator. It continues to rotate upwards until it is straight up at the South Magnetic Pole. Inclination can be measured with a dip circle.

An isoclinic chart (map of inclination contours) for the Earth's magnetic field is shown below.

Declination Edit

Declination is positive for an eastward deviation of the field relative to true north. It can be estimated by comparing the magnetic north–south heading on a compass with the direction of a celestial pole. Maps typically include information on the declination as an angle or a small diagram showing the relationship between magnetic north and true north. Information on declination for a region can be represented by a chart with isogonic lines (contour lines with each line representing a fixed declination).

Geographical variation Edit

Components of the Earth's magnetic field at the surface from the World Magnetic Model for 2015. [15]

Dipolar approximation Edit

Near the surface of the Earth, its magnetic field can be closely approximated by the field of a magnetic dipole positioned at the center of the Earth and tilted at an angle of about 11° with respect to the rotational axis of the Earth. [13] The dipole is roughly equivalent to a powerful bar magnet, with its south pole pointing towards the geomagnetic North Pole. [16] This may seem surprising, but the north pole of a magnet is so defined because, if allowed to rotate freely, it points roughly northward (in the geographic sense). Since the north pole of a magnet attracts the south poles of other magnets and repels the north poles, it must be attracted to the south pole of Earth's magnet. The dipolar field accounts for 80–90% of the field in most locations. [12]

Magnetic poles Edit

Historically, the north and south poles of a magnet were first defined by the Earth's magnetic field, not vice versa, since one of the first uses for a magnet was as a compass needle. A magnet's North pole is defined as the pole that is attracted by the Earth's North Magnetic Pole when the magnet is suspended so it can turn freely. Since opposite poles attract, the North Magnetic Pole of the Earth is really the south pole of its magnetic field (the place where the field is directed downward into the Earth). [17] [18] [19] [20]

The positions of the magnetic poles can be defined in at least two ways: locally or globally. [21] The local definition is the point where the magnetic field is vertical. [22] This can be determined by measuring the inclination. The inclination of the Earth's field is 90° (downwards) at the North Magnetic Pole and -90° (upwards) at the South Magnetic Pole. The two poles wander independently of each other and are not directly opposite each other on the globe. Movements of up to 40 kilometres (25 mi) per year have been observed for the North Magnetic Pole. Over the last 180 years, the North Magnetic Pole has been migrating northwestward, from Cape Adelaide in the Boothia Peninsula in 1831 to 600 kilometres (370 mi) from Resolute Bay in 2001. [23] The magnetic equator is the line where the inclination is zero (the magnetic field is horizontal).

The global definition of the Earth's field is based on a mathematical model. If a line is drawn through the center of the Earth, parallel to the moment of the best-fitting magnetic dipole, the two positions where it intersects the Earth's surface are called the North and South geomagnetic poles. If the Earth's magnetic field were perfectly dipolar, the geomagnetic poles and magnetic dip poles would coincide and compasses would point towards them. However, the Earth's field has a significant non-dipolar contribution, so the poles do not coincide and compasses do not generally point at either.

Earth's magnetic field, predominantly dipolar at its surface, is distorted further out by the solar wind. This is a stream of charged particles leaving the Sun's corona and accelerating to a speed of 200 to 1000 kilometres per second. They carry with them a magnetic field, the interplanetary magnetic field (IMF). [24]

The solar wind exerts a pressure, and if it could reach Earth's atmosphere it would erode it. However, it is kept away by the pressure of the Earth's magnetic field. The magnetopause, the area where the pressures balance, is the boundary of the magnetosphere. Despite its name, the magnetosphere is asymmetric, with the sunward side being about 10 Earth radii out but the other side stretching out in a magnetotail that extends beyond 200 Earth radii. [25] Sunward of the magnetopause is the bow shock, the area where the solar wind slows abruptly. [24]

Inside the magnetosphere is the plasmasphere, a donut-shaped region containing low-energy charged particles, or plasma. This region begins at a height of 60 km, extends up to 3 or 4 Earth radii, and includes the ionosphere. This region rotates with the Earth. [25] There are also two concentric tire-shaped regions, called the Van Allen radiation belts, with high-energy ions (energies from 0.1 to 10 million electron volts (MeV)). The inner belt is 1–2 Earth radii out while the outer belt is at 4–7 Earth radii. The plasmasphere and Van Allen belts have partial overlap, with the extent of overlap varying greatly with solar activity. [26]

As well as deflecting the solar wind, the Earth's magnetic field deflects cosmic rays, high-energy charged particles that are mostly from outside the Solar System. Many cosmic rays are kept out of the Solar System by the Sun's magnetosphere, or heliosphere. [27] By contrast, astronauts on the Moon risk exposure to radiation. Anyone who had been on the Moon's surface during a particularly violent solar eruption in 2005 would have received a lethal dose. [24]

Some of the charged particles do get into the magnetosphere. These spiral around field lines, bouncing back and forth between the poles several times per second. In addition, positive ions slowly drift westward and negative ions drift eastward, giving rise to a ring current. This current reduces the magnetic field at the Earth's surface. [24] Particles that penetrate the ionosphere and collide with the atoms there give rise to the lights of the aurorae and also emit X-rays. [25]

The varying conditions in the magnetosphere, known as space weather, are largely driven by solar activity. If the solar wind is weak, the magnetosphere expands while if it is strong, it compresses the magnetosphere and more of it gets in. Periods of particularly intense activity, called geomagnetic storms, can occur when a coronal mass ejection erupts above the Sun and sends a shock wave through the Solar System. Such a wave can take just two days to reach the Earth. Geomagnetic storms can cause a lot of disruption the "Halloween" storm of 2003 damaged more than a third of NASA's satellites. The largest documented storm occurred in 1859. It induced currents strong enough to short out telegraph lines, and aurorae were reported as far south as Hawaii. [24] [28]

Short-term variations Edit

The geomagnetic field changes on time scales from milliseconds to millions of years. Shorter time scales mostly arise from currents in the ionosphere (ionospheric dynamo region) and magnetosphere, and some changes can be traced to geomagnetic storms or daily variations in currents. Changes over time scales of a year or more mostly reflect changes in the Earth's interior, particularly the iron-rich core. [12]

Frequently, the Earth's magnetosphere is hit by solar flares causing geomagnetic storms, provoking displays of aurorae. The short-term instability of the magnetic field is measured with the K-index. [29]

Data from THEMIS show that the magnetic field, which interacts with the solar wind, is reduced when the magnetic orientation is aligned between Sun and Earth – opposite to the previous hypothesis. During forthcoming solar storms, this could result in blackouts and disruptions in artificial satellites. [30]

Secular variation Edit

Changes in Earth's magnetic field on a time scale of a year or more are referred to as secular variation. Over hundreds of years, magnetic declination is observed to vary over tens of degrees. [12] The animation shows how global declinations have changed over the last few centuries. [31]

The direction and intensity of the dipole change over time. Over the last two centuries the dipole strength has been decreasing at a rate of about 6.3% per century. [12] At this rate of decrease, the field would be negligible in about 1600 years. [32] However, this strength is about average for the last 7 thousand years, and the current rate of change is not unusual. [33]

A prominent feature in the non-dipolar part of the secular variation is a westward drift at a rate of about 0.2 degrees per year. [32] This drift is not the same everywhere and has varied over time. The globally averaged drift has been westward since about 1400 AD but eastward between about 1000 AD and 1400 AD. [34]

Changes that predate magnetic observatories are recorded in archaeological and geological materials. Such changes are referred to as paleomagnetic secular variation or paleosecular variation (PSV). The records typically include long periods of small change with occasional large changes reflecting geomagnetic excursions and reversals. [35]

In July 2020 scientists report that analysis of simulations and a recent observational field model show that maximum rates of directional change of Earth's magnetic field reached

10° per year – almost 100 times faster than current changes and 10 times faster than previously thought. [36] [37]

Studies of lava flows on Steens Mountain, Oregon, indicate that the magnetic field could have shifted at a rate of up to 6 degrees per day at some time in Earth's history, which significantly challenges the popular understanding of how the Earth's magnetic field works. [38] This finding was later attributed to unusual rock magnetic properties of the lava flow under study, not rapid field change, by one of the original authors of the 1995 study. [39]

Magnetic field reversals Edit

Although generally Earth's field is approximately dipolar, with an axis that is nearly aligned with the rotational axis, occasionally the North and South geomagnetic poles trade places. Evidence for these geomagnetic reversals can be found in basalts, sediment cores taken from the ocean floors, and seafloor magnetic anomalies. [40] Reversals occur nearly randomly in time, with intervals between reversals ranging from less than 0.1 million years to as much as 50 million years. The most recent geomagnetic reversal, called the Brunhes–Matuyama reversal, occurred about 780,000 years ago. [23] [41] A related phenomenon, a geomagnetic excursion, takes the dipole axis across the equator and then back to the original polarity. [42] [43] The Laschamp event is an example of an excursion, occurring during the last ice age (41,000 years ago).

The past magnetic field is recorded mostly by strongly magnetic minerals, particularly iron oxides such as magnetite, that can carry a permanent magnetic moment. This remanent magnetization, or remanence, can be acquired in more than one way. In lava flows, the direction of the field is "frozen" in small minerals as they cool, giving rise to a thermoremanent magnetization. In sediments, the orientation of magnetic particles acquires a slight bias towards the magnetic field as they are deposited on an ocean floor or lake bottom. This is called detrital remanent magnetization. [8]

Thermoremanent magnetization is the main source of the magnetic anomalies around mid-ocean ridges. As the seafloor spreads, magma wells up from the mantle, cools to form new basaltic crust on both sides of the ridge, and is carried away from it by seafloor spreading. As it cools, it records the direction of the Earth's field. When the Earth's field reverses, new basalt records the reversed direction. The result is a series of stripes that are symmetric about the ridge. A ship towing a magnetometer on the surface of the ocean can detect these stripes and infer the age of the ocean floor below. This provides information on the rate at which seafloor has spread in the past. [8]

Radiometric dating of lava flows has been used to establish a geomagnetic polarity time scale, part of which is shown in the image. This forms the basis of magnetostratigraphy, a geophysical correlation technique that can be used to date both sedimentary and volcanic sequences as well as the seafloor magnetic anomalies. [8]

Earliest appearance Edit

Paleomagnetic studies of Paleoarchean lava in Australia and conglomerate in South Africa have concluded that the magnetic field has been present since at least about 3,450 million years ago . [44] [45] [46]

Future Edit

At present, the overall geomagnetic field is becoming weaker the present strong deterioration corresponds to a 10–15% decline over the last 150 years and has accelerated in the past several years geomagnetic intensity has declined almost continuously from a maximum 35% above the modern value achieved approximately 2,000 years ago. The rate of decrease and the current strength are within the normal range of variation, as shown by the record of past magnetic fields recorded in rocks.

The nature of Earth's magnetic field is one of heteroscedastic fluctuation. An instantaneous measurement of it, or several measurements of it across the span of decades or centuries, are not sufficient to extrapolate an overall trend in the field strength. It has gone up and down in the past for unknown reasons. Also, noting the local intensity of the dipole field (or its fluctuation) is insufficient to characterize Earth's magnetic field as a whole, as it is not strictly a dipole field. The dipole component of Earth's field can diminish even while the total magnetic field remains the same or increases.

The Earth's magnetic north pole is drifting from northern Canada towards Siberia with a presently accelerating rate—10 kilometres (6.2 mi) per year at the beginning of the 20th century, up to 40 kilometres (25 mi) per year in 2003, [23] and since then has only accelerated. [47] [48]

Earth's core and the geodynamo Edit

The Earth's magnetic field is believed to be generated by electric currents in the conductive iron alloys of its core, created by convection currents due to heat escaping from the core. However the process is complex, and computer models that reproduce some of its features have only been developed in the last few decades.

The Earth and most of the planets in the Solar System, as well as the Sun and other stars, all generate magnetic fields through the motion of electrically conducting fluids. [50] The Earth's field originates in its core. This is a region of iron alloys extending to about 3400 km (the radius of the Earth is 6370 km). It is divided into a solid inner core, with a radius of 1220 km, and a liquid outer core. [51] The motion of the liquid in the outer core is driven by heat flow from the inner core, which is about 6,000 K (5,730 °C 10,340 °F), to the core-mantle boundary, which is about 3,800 K (3,530 °C 6,380 °F). [52] The heat is generated by potential energy released by heavier materials sinking toward the core (planetary differentiation, the iron catastrophe) as well as decay of radioactive elements in the interior. The pattern of flow is organized by the rotation of the Earth and the presence of the solid inner core. [53]

The mechanism by which the Earth generates a magnetic field is known as a dynamo. [50] The magnetic field is generated by a feedback loop: current loops generate magnetic fields (Ampère's circuital law) a changing magnetic field generates an electric field (Faraday's law) and the electric and magnetic fields exert a force on the charges that are flowing in currents (the Lorentz force). [54] These effects can be combined in a partial differential equation for the magnetic field called the magnetic induction equation,

where u is the velocity of the fluid B is the magnetic B-field and η=1/σμ is the magnetic diffusivity, which is inversely proportional to the product of the electrical conductivity σ and the permeability μ . [55] The term ∂B/∂t is the time derivative of the field ∇ 2 is the Laplace operator and ∇× is the curl operator.

The first term on the right hand side of the induction equation is a diffusion term. In a stationary fluid, the magnetic field declines and any concentrations of field spread out. If the Earth's dynamo shut off, the dipole part would disappear in a few tens of thousands of years. [55]

In a perfect conductor ( σ = ∞ ), there would be no diffusion. By Lenz's law, any change in the magnetic field would be immediately opposed by currents, so the flux through a given volume of fluid could not change. As the fluid moved, the magnetic field would go with it. The theorem describing this effect is called the frozen-in-field theorem. Even in a fluid with a finite conductivity, new field is generated by stretching field lines as the fluid moves in ways that deform it. This process could go on generating new field indefinitely, were it not that as the magnetic field increases in strength, it resists fluid motion. [55]

The motion of the fluid is sustained by convection, motion driven by buoyancy. The temperature increases towards the center of the Earth, and the higher temperature of the fluid lower down makes it buoyant. This buoyancy is enhanced by chemical separation: As the core cools, some of the molten iron solidifies and is plated to the inner core. In the process, lighter elements are left behind in the fluid, making it lighter. This is called compositional convection. A Coriolis effect, caused by the overall planetary rotation, tends to organize the flow into rolls aligned along the north–south polar axis. [53] [55]

A dynamo can amplify a magnetic field, but it needs a "seed" field to get it started. [55] For the Earth, this could have been an external magnetic field. Early in its history the Sun went through a T-Tauri phase in which the solar wind would have had a magnetic field orders of magnitude larger than the present solar wind. [56] However, much of the field may have been screened out by the Earth's mantle. An alternative source is currents in the core-mantle boundary driven by chemical reactions or variations in thermal or electric conductivity. Such effects may still provide a small bias that are part of the boundary conditions for the geodynamo. [57]

The average magnetic field in the Earth's outer core was calculated to be 25 gauss, 50 times stronger than the field at the surface. [58]

Numerical models Edit

Simulating the geodynamo by computer requires numerically solving a set of nonlinear partial differential equations for the magnetohydrodynamics (MHD) of the Earth's interior. Simulation of the MHD equations is performed on a 3D grid of points and the fineness of the grid, which in part determines the realism of the solutions, is limited mainly by computer power. For decades, theorists were confined to creating kinematic dynamo computer models in which the fluid motion is chosen in advance and the effect on the magnetic field calculated. Kinematic dynamo theory was mainly a matter of trying different flow geometries and testing whether such geometries could sustain a dynamo. [59]

The first self-consistent dynamo models, ones that determine both the fluid motions and the magnetic field, were developed by two groups in 1995, one in Japan [60] and one in the United States. [1] [61] The latter received attention because it successfully reproduced some of the characteristics of the Earth's field, including geomagnetic reversals. [59]

Currents in the ionosphere and magnetosphere Edit

Electric currents induced in the ionosphere generate magnetic fields (ionospheric dynamo region). Such a field is always generated near where the atmosphere is closest to the Sun, causing daily alterations that can deflect surface magnetic fields by as much as one degree. Typical daily variations of field strength are about 25 nanoteslas (nT) (one part in 2000), with variations over a few seconds of typically around 1 nT (one part in 50,000). [62]

Detection Edit

The Earth's magnetic field strength was measured by Carl Friedrich Gauss in 1832 [63] and has been repeatedly measured since then, showing a relative decay of about 10% over the last 150 years. [64] The Magsat satellite and later satellites have used 3-axis vector magnetometers to probe the 3-D structure of the Earth's magnetic field. The later Ørsted satellite allowed a comparison indicating a dynamic geodynamo in action that appears to be giving rise to an alternate pole under the Atlantic Ocean west of South Africa. [65]

Governments sometimes operate units that specialize in measurement of the Earth's magnetic field. These are geomagnetic observatories, typically part of a national Geological survey, for example the British Geological Survey's Eskdalemuir Observatory. Such observatories can measure and forecast magnetic conditions such as magnetic storms that sometimes affect communications, electric power, and other human activities.

The International Real-time Magnetic Observatory Network, with over 100 interlinked geomagnetic observatories around the world, has been recording the Earth's magnetic field since 1991.

The military determines local geomagnetic field characteristics, in order to detect anomalies in the natural background that might be caused by a significant metallic object such as a submerged submarine. Typically, these magnetic anomaly detectors are flown in aircraft like the UK's Nimrod or towed as an instrument or an array of instruments from surface ships.

Commercially, geophysical prospecting companies also use magnetic detectors to identify naturally occurring anomalies from ore bodies, such as the Kursk Magnetic Anomaly.

Crustal magnetic anomalies Edit

Magnetometers detect minute deviations in the Earth's magnetic field caused by iron artifacts, kilns, some types of stone structures, and even ditches and middens in archaeological geophysics. Using magnetic instruments adapted from airborne magnetic anomaly detectors developed during World War II to detect submarines, [67] the magnetic variations across the ocean floor have been mapped. Basalt — the iron-rich, volcanic rock making up the ocean floor [68] — contains a strongly magnetic mineral (magnetite) and can locally distort compass readings. The distortion was recognized by Icelandic mariners as early as the late 18th century. [69] More important, because the presence of magnetite gives the basalt measurable magnetic properties, these magnetic variations have provided another means to study the deep ocean floor. When newly formed rock cools, such magnetic materials record the Earth's magnetic field. [69]

Statistical models Edit

Each measurement of the magnetic field is at a particular place and time. If an accurate estimate of the field at some other place and time is needed, the measurements must be converted to a model and the model used to make predictions.

Spherical harmonics Edit

The most common way of analyzing the global variations in the Earth's magnetic field is to fit the measurements to a set of spherical harmonics. This was first done by Carl Friedrich Gauss. [70] Spherical harmonics are functions that oscillate over the surface of a sphere. They are the product of two functions, one that depends on latitude and one on longitude. The function of longitude is zero along zero or more great circles passing through the North and South Poles the number of such nodal lines is the absolute value of the order m . The function of latitude is zero along zero or more latitude circles this plus the order is equal to the degree ℓ. Each harmonic is equivalent to a particular arrangement of magnetic charges at the center of the Earth. A monopole is an isolated magnetic charge, which has never been observed. A dipole is equivalent to two opposing charges brought close together and a quadrupole to two dipoles brought together. A quadrupole field is shown in the lower figure on the right. [12]

Spherical harmonics can represent any scalar field (function of position) that satisfies certain properties. A magnetic field is a vector field, but if it is expressed in Cartesian components X, Y, Z , each component is the derivative of the same scalar function called the magnetic potential. Analyses of the Earth's magnetic field use a modified version of the usual spherical harmonics that differ by a multiplicative factor. A least-squares fit to the magnetic field measurements gives the Earth's field as the sum of spherical harmonics, each multiplied by the best-fitting Gauss coefficient gm ℓ or hm ℓ . [12]

The lowest-degree Gauss coefficient, g 0 0 , gives the contribution of an isolated magnetic charge, so it is zero. The next three coefficients – g 1 0 , g 1 1 , and h 1 1 – determine the direction and magnitude of the dipole contribution. The best fitting dipole is tilted at an angle of about 10° with respect to the rotational axis, as described earlier. [12]

Radial dependence Edit

Spherical harmonic analysis can be used to distinguish internal from external sources if measurements are available at more than one height (for example, ground observatories and satellites). In that case, each term with coefficient gm ℓ or hm ℓ can be split into two terms: one that decreases with radius as 1/ r ℓ+1 and one that increases with radius as r ℓ . The increasing terms fit the external sources (currents in the ionosphere and magnetosphere). However, averaged over a few years the external contributions average to zero. [12]

The remaining terms predict that the potential of a dipole source ( ℓ=1 ) drops off as 1/ r 2 . The magnetic field, being a derivative of the potential, drops off as 1/ r 3 . Quadrupole terms drop off as 1/ r 4 , and higher order terms drop off increasingly rapidly with the radius. The radius of the outer core is about half of the radius of the Earth. If the field at the core-mantle boundary is fit to spherical harmonics, the dipole part is smaller by a factor of about 8 at the surface, the quadrupole part by a factor of 16, and so on. Thus, only the components with large wavelengths can be noticeable at the surface. From a variety of arguments, it is usually assumed that only terms up to degree 14 or less have their origin in the core. These have wavelengths of about 2,000 kilometres (1,200 mi) or less. Smaller features are attributed to crustal anomalies. [12]

Global models Edit

The International Association of Geomagnetism and Aeronomy maintains a standard global field model called the International Geomagnetic Reference Field. It is updated every five years. The 11th-generation model, IGRF11, was developed using data from satellites (Ørsted, CHAMP and SAC-C) and a world network of geomagnetic observatories. [71] The spherical harmonic expansion was truncated at degree 10, with 120 coefficients, until 2000. Subsequent models are truncated at degree 13 (195 coefficients). [72]

Another global field model, called the World Magnetic Model, is produced jointly by the United States National Centers for Environmental Information (formerly the National Geophysical Data Center) and the British Geological Survey. This model truncates at degree 12 (168 coefficients) with an approximate spatial resolution of 3,000 kilometers. It is the model used by the United States Department of Defense, the Ministry of Defence (United Kingdom), the United States Federal Aviation Administration (FAA), the North Atlantic Treaty Organization (NATO), and the International Hydrographic Organization as well as in many civilian navigation systems. [73]

A third model, produced by the Goddard Space Flight Center (NASA and GSFC) and the Danish Space Research Institute, uses a "comprehensive modeling" approach that attempts to reconcile data with greatly varying temporal and spatial resolution from ground and satellite sources. [74]

For users with higher accuracy needs, the United States National Centers for Environmental Information developed the Enhanced Magnetic Model (EMM), which extends to degree and order 790 and resolves magnetic anomalies down to a wavelength of 56 kilometers. It was compiled from satellite, marine, aeromagnetic and ground magnetic surveys. As of 2018 [update] , the latest version, EMM2017, includes data from The European Space Agency's Swarm satellite mission. [75]

The oceans contribute to Earth's magnetic field. Seawater is an electrical conductor, and therefore interacts with the magnetic field. As the tides cycle around the ocean basins, the ocean water essentially tries to pull the geomagnetic field lines along. Because the salty water is slightly conductive, the interaction is relatively weak: the strongest component is from the regular lunar tide that happens about twice per day. Other contributions come from ocean swell, eddies, and even tsunamis. [76]

The strength of the interaction depends also on the temperature of the ocean water. The entire heat stored in the ocean can now be inferred from observations of the Earth's magnetic field. [77] [76]

Animals, including birds and turtles, can detect the Earth's magnetic field, and use the field to navigate during migration. [78] Some researchers have found that cows and wild deer tend to align their bodies north–south while relaxing, but not when the animals are under high-voltage power lines, suggesting that magnetism is responsible. [79] [80] Other researchers reported in 2011 that they could not replicate those findings using different Google Earth images. [81]

Very weak electromagnetic fields disrupt the magnetic compass used by European robins and other songbirds, which use the Earth's magnetic field to navigate. Neither power lines nor cellphone signals are to blame for the electromagnetic field effect on the birds [82] instead, the culprits have frequencies between 2 kHz and 5 MHz. These include AM radio signals and ordinary electronic equipment that might be found in businesses or private homes. [83]


Luxury Ship Le Commandant Charcot Leads You on the Ultimate Polar Expedition

Some people dream about luxurious cruises, others are bored with typical destinations and would prefer to go for something truly remarkable. Now, there&rsquos a way to enjoy both of these experiences. Le Commandant Charcot is ready to take its first passengers on a polar expedition tailored for even the most sophisticated tastes.

Built by the French cruise line PONANT in their Norway shipyard, Le Commandant Charcot is 492 ft (120 meters) long and 91 ft (28 meters) wide. All of its 135 suites and cabins have an exquisite design and deluxe features, such as wide, private terraces, while the duplex suites also have Jacuzzis.

And, if you&rsquore one of the lucky guests on board, you can also enjoy a variety of sumptuous common areas, like the winter garden, 2 restaurants, one of which has a panoramic view, and the interior pool. Or, you can take advantage of the wellness area and indulge at the spa, in the sauna or at the fitness room. After all, what could be better than that after going out in the polar regions and exploring the surroundings? A team of professional guides is there to lead the expeditions and teach the guests more about these unique places.

This cruise ship also features a unique Observatory Parlor, where specialists in the North and South Pole will hold insightful conferences on historical, geological and biological themes related to the Poles.

And, if you&rsquore not already blown away by the idea of a luxury cruise ship for polar expeditions, there&rsquos even more good news about Le Commandant Charcot. This is actually the first vessel of its kind to be electric and LNG- (liquefied natural gas) powered, which means it&rsquos better for the environment.

With a 34 MW electric motor, Le Commandant Charcot can reach a speed of 15 knots, with zero smoke and soot emissions.


Watch the video: Η πόλη που για τέσσερις μήνες δε βγαίνει ο ήλιος, και δεν επιτρέπεται να πεθάνεις!! (July 2022).


Comments:

  1. Gukasa

    Authoritative post :), curious ...

  2. Conradin

    I know, how it is necessary to act, write in personal

  3. Vumi

    I believe that you are wrong. I'm sure. Let's discuss. Email me at PM.

  4. Hawley

    I saw it by chance. Not expected.

  5. Tejas

    And out of shame or shame!

  6. Cranly

    A good question

  7. Ocvran

    I think I make mistakes. Write to me in PM, speak.



Write a message

DateWhereEvents
September 16, 1954Groton, Conn.