Ahnighito (meteorite)

from Wikipedia, the free encyclopedia
Robert Peary and the Ahnighito Meteorite, 1897
The meteorite Ahnighito (in the background), "Woman" (front) and "Dog" (on the stand) in the American Museum of Natural History
The Ahnighito meteorite in the American Museum of Natural History

The meteorite Ahnighito (also "Saviksue" or "tent") is an iron meteorite . It is classified as a Group III AB medium octahedrite and consists of 91% iron , 7.58% nickel , 19.2  ppm gallium , 36.0 ppm germanium, and 5.0 ppm iridium . Robert Peary found him in Greenland in 1897 and transported him to New York . Today the Ahnighito is in the Arthur Ross Hall of Meteorites of the American Museum of Natural History in New York. It is the largest meteorite exhibited in a museum in the world.

With a weight of 31  t , the Ahnighito is the third largest meteorite that has been discovered so far. The largest meteorite preserved in one piece, the Hoba meteorite , at around 60 tonnes , is located in Namibia , on the grounds of the "Hoba" farm near Grootfontein . A 37 t heavy fragment of the Campo del Cielo meteorite , the second largest meteorite fragment , lies on the border between the provinces of Chaco and Santiago del Estero in Argentina .

description

The Ahnighito meteorite is the main mass of the Cape York meteorite , which originally weighed probably 200 tons. The Cape York meteorite, which broke over Melville Bay almost 10,000 years ago when it entered the earth's atmosphere , is named after the place of its discovery, Cape York in Greenland in the administrative district of Avanersuaq . A total of 12 parts of the Cape York meteorite with a total weight of 58 t have been found so far. Besides the Ahnighito are in the American Museum of Natural History two other sections of the Cape York meteorite, "woman" (Woman) with a weight of 3 t and "dog" (Dog) with 400 kg. The 3.4 m × 2.1 m × 1.7 m tall Ahnighito stands in the Arthur Ross Hall of the American Museum of Natural History on massive columns that reach through the floor to the rock below the museum. In 2003 the exhibition was redesigned so that the pillars are no longer visible today.

The meteorite is about 4.6 billion years old and was exposed to cosmic rays for about 93 million years . It was separated from its mother body much less time ago than other octahedrites of chemical group III AB, which as a rule have a much longer irradiation age of around 650 million years. The surface of the dark brown meteorite is covered with greenish inclusions. All Troilit inclusions are oriented in the same direction and show the influence of gravity during solidification. Some parts of the meteorite have been ground, polished and etched with nitric acid containing methanol in order to make the Widmanstätten structures and the Neumann lines particularly clear on the Ahnighito visible.

history

For centuries, the Inuit who lived nearby used the iron from the meteorite to make tools and harpoons. The first rumors about the existence of the meteorite existed in scientific circles as early as 1818. While searching for the Northwest Passage in Northwest Greenland, the British rear admiral and polar explorer John Ross encountered an Inuit tribe who, to their astonishment, owned knife blades, harpoon points and engraved tools made of meteoritic iron . Five expeditions between 1818 and 1883 failed to clarify the origin of the iron. The Inuit interviewed refused to disclose the location of the meteorites. Robert Peary eventually convinced them by offering them guns and other items made of iron.

The Inuit had already tried to transport away part of the upper body of the "woman", which had been separated from the torso by the constant chiselling of small fragments over the centuries. When the dog sled with the piece of meteorite was on the pack ice, the ice suddenly broke and the head of the "woman" disappeared into the water. Since then, no further attempts have been made to remove any more parts.

Loading the meteorite

In May 1894 Robert Peary and his local guides reached the site on the meteorite island on Melville Bay on foot. In the summer of 1894 he tried to reach Melville Bay with his ship “Falcon” in order to load the two smaller meteorites “Woman” and “Dog”, which were about 7 km away from Ahnighito on the mainland. Because of the unusually cold polar summer of 1894, Peary's attempt to reach Cape York failed. In August 1895, on his third trip to Greenland, with the help of wooden sledges, he managed to pull the two meteorites "Woman" and "Dog" to his ship "Kite" and load them. It was the first Greenland meteorite to hit the United States .

For his fifth voyage to Greenland in 1896, Peary chartered the steamship “Hope” to bring the meteorite to New York, to collect art and cultural objects for ethnographic exhibitions and to gain experience for reaching the North Pole . His wife Josephine Diebitsch Peary and his three-year-old daughter Marie Ahnighito Peary accompanied him on the expedition. With hydraulic jacks and the support of 100 Inuit, Peary was able to set up a ramp for loading onto the "Hope" and pull the meteorite on board over a heavy bridge construction equipped with counterweights in six days. There the meteorite was lowered over the keel and firmly wedged in order to put the center of gravity of the ship as low as possible. On August 20, 1897, the meteorite was loaded, and on September 30, 1897 the "Hope" reached Brooklyn . The Ahnighito remained at the Navy Yard in Brooklyn until Peary's wife him in 1904 for 40,000 dollars sold to the American Museum of Natural History.

Minik in New York shortly after his arrival

When the meteorite was transported to New York, six Inuit were on board, whose fate shows the dark side of the discovery story. The Inuit fell ill after a few weeks and died, only one young boy, Minik Wallace , survived. When his father died of tuberculosis , the boy was simulated a funeral according to traditional rites. At the age of 16, Minik Wallace discovered that his father's skeleton was on display in the museum's anthropological collection, not far from the Ahnighito.

More fragments of the Cape York meteorite

A total of twelve fragments of the Cape York meteorite are known. In 1963, the Danish meteorite researcher Vagn Buchwald discovered another large fragment of the Cape York meteorite on the island of Agpalilik. The Agpalilik meteorite (probably the "man") weighs around 20 t and is in the Geological Museum of the University of Copenhagen . Other smaller fragments are z. B. the 3 t Savik-I meteorite, which was found by Knud Rasmussen in 1913; the 48 kg Thule meteorite discovered by geologist Mark Meier in 1955; the 7.8 kg Savik II meteorite and the 250 kg Tunorput fragment, which was found in the sea in 1984 by the hunter Jeremias Petersen. By comparing the chemical compositions, Vagn Buchwald recognized that a fragment, which was found near an old Inuit camp on the Knud Peninsula in Canada , part of Ellesmere Island, belonged to the Cape York meteorite. This 1.6 kg fragment, which was named Akpohon, appears to have been transported over 600 km from the place where it was felled to where it was found in Canada.

literature

  • Monica M. Grady: Catalog of Meteorites. 5th edition. Cambridge University Press, Cambridge 2000, ISBN 978-0-521-66303-8
  • Emersleben, Otto: Robert Edwin Peary: an American dream of the pole. New Life Publishing House, Berlin 1991, ISBN 3-355-01289-0 .
  • Fleming, Fergus: Ninety degrees north. The dream of the pole. Piper, Munich 2004, ISBN 3-492-24205-7 .
  • Harper, Kenn: The soul of my father. Minik - The Eskimo of New York. With a foreword by Kevin Spacey. Diana Verlag, Munich / Zurich 2001, ISBN 3-453-19143-9 .

Web links

Individual evidence

  1. ↑ The Inuit called the meteorite "tent". Marie Ahnighito Peary explained the name Ahnighito, which she herself had as a middle name, as follows: “It is the name of the Eskimo woman who made my first fur clothes (as a snow baby). The name is usually Arnakittoq. "From Nunatsiaq News, Taissumani: A Day in Arctic History, Sept. 12, 1893 - The" Snowbaby "is Born in Greenland. ( Memento from July 11, 2008 in the Internet Archive )
  2. ↑ a b c d Montréal Planetarium, Cape York
  3. ^ History of Meteorites, Cape York , Astronomical Research Network 2006
  4. ↑ Singen observatory e. V., meteorite Hoba ( Memento from June 28, 2009 in the Internet Archive )
  5. ↑ Montréal Planetarium, Campo del Cielo ( Memento from June 25, 2009 in the Internet Archive )
  6. ↑ Mike Jensen: Largest Meteorites in the World ( Memento from November 19, 2012 in the Internet Archive )
  7. ↑ Peter Seroka: Mineralienportrait Eisen, Eisen in Grönland
  8. ↑ Discovery of Cape York Iron Meteorite (PDF; 369 kB) Meteoritical Bulletin, No. 28, Moscow 1963
  9. ↑ Natural History, Arthur Ross Hall of Meteorites reopens September 20 ( Memento from July 8, 2012 in the web archive archive.today )
  10. ^ TA Rickard: The Use of Meteoric Iron . In: The Journal of the Royal Anthropological Institute of Great Britain and Ireland . No. 71, 1941, pp. 55-66.
  11. ^ VF Buchwald: On the Use of Iron by the Eskimos in Greenland . In: Materials Characterization . No. 29, 1992, pp. 139-176
  12. ^ American Museum of Natural History, Fragments of Cape York
  13. ↑ Women and the American Experience, Josephine Diebitsch Peary ( Memento from August 7, 2007 in the Internet Archive )
  14. ↑ Women and the American Experience, Marie Peary Stafford (1893–1978) ( Memento August 7, 2007 in the Internet Archive )
  15. ^ Mark Bostick: The Cape York Misconception
  16. ↑ Kenn Harper: The Soul of My Father: Minik - The Eskimo of New York. Diana Verlag, Munich Zurich 2001, ISBN 3-453-19143-9 .
  17. ↑ Greenlandic Meteorites ( Memento from June 9, 2007 in the Internet Archive )
  18. ^ The Meteoritical Society, Cape York
  19. ^ VF Buchwald: Thermal Migration III: Its Occurrence in Cape York and Other Iron Meteorites , Meteoritics, Vol. 22, p. 343
  20. ^ Meteoritical Bulletin Database, Cape York