page_title: Meteorite
section_title: Antarctica
hierarchical_section_title: Meteorite / Meteorite recovery / Finds / Antarctica
caption_attribution_description: Español: Vista microscópica de la estructura interna del ALH84001 English: Structures on ALH84001 meteorite Français&#160;: Un fragment de la météorite w:ALH84001. Il révèle par w:microscopie électronique à balayage des structures ressemblant à des w:bactéries, possibles formes de w:vie sur Mars. voir aussi&#160;: Category:Alien et Category:Astrobiology
context_page_description: A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon. When the original object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate energy. It then becomes a meteor and forms a fireball, also known as a shooting star or falling star; astronomers call the brightest examples "bolides". Once it settles on the larger body's surface, the meteor becomes a meteorite. Meteorites vary greatly in size. For geologists, a bolide is a meteorite large enough to create an impact crater.
  Meteorites that are recovered after being observed as they transit the atmosphere and impact the Earth are called meteorite falls. All others are known as meteorite finds. As of August 2018, there were about 1,412 witnessed falls that have specimens in the world's collections. As of 2018, there are more than 59,200 well-documented meteorite finds.
context_section_description: A few meteorites were found in Antarctica between 1912 and 1964. In 1969, the 10th Japanese Antarctic Research Expedition found nine meteorites on a blue ice field near the Yamato Mountains. With this discovery, came the realization that movement of ice sheets might act to concentrate meteorites in certain areas. After a dozen other specimens were found in the same place in 1973, a Japanese expedition was launched in 1974 dedicated to the search for meteorites. This team recovered nearly 700 meteorites.
  Shortly thereafter, the United States began its own program to search for Antarctic meteorites, operating along the Transantarctic Mountains on the other side of the continent: the Antarctic Search for Meteorites (ANSMET) program. European teams, starting with a consortium called "EUROMET" in the 1990/91 season, and continuing with a program by the Italian Programma Nazionale di Ricerche in Antartide have also conducted systematic searches for Antarctic meteorites.
  The Antarctic Scientific Exploration of China has conducted successful meteorite searches since 2000. A Korean program (KOREAMET) was launched in 2007 and has collected a few meteorites. The combined efforts of all of these expeditions have produced more than 23,000 classified meteorite specimens since 1974, with thousands more that have not yet been classified. For more information see the article by Harvey (2003).
caption: A scanning electron microscope revealed structures resembling bacteria fossils - in the meteorite ALH84001 discovered in Antarctica in 1984. Microscopically, the features were initially interpreted as fossils of bacteria-like lifeforms. It has since been shown that similar magnetite structures can form without the presence of microbial life in hydrothermal systems.[37]
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