ALH 84001
ALH 84001 is an ancient Martian meteorite found in Antarctica, famous for the 1996 claim of possible microfossils.
ALH 84001 is a 1.93-kilogram Martian meteorite found by an American meteorite search team in the Allan Hills area of Antarctica on 27 December 1984. The name means it was the first specimen catalogued from the 1984 Allan Hills season. It was first classified as a diogenite from Vesta and recognised as Martian only in 1993.
The rock is an orthopyroxenite about 4.1 billion years old, making it one of the oldest Martian samples. Small carbonate globules within it formed around 3.9 billion years ago, when water seeped through the Martian crust. In August 1996, NASA scientists announced that tiny magnetite crystals, organic molecules and worm-like shapes in the carbonates could be signs of ancient life.
Further studies found non-biological explanations for each feature, and most scientists do not accept the evidence as proof of life. Nevertheless, ALH 84001 remains a landmark, showing that Mars once had liquid water near its surface and inspiring a generation of Mars exploration.
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