Evidence Of Microbial Life On Ancient Mars
A group of researchers from NASA’s Johnson Space Flight Center, led by David McKay, reported in 1996 that they had found proof of microscopic fossil life in a meteorite from Mars.
The evidence was fascinating and contentious from the beginning, and it still is.
When an asteroid or comet struck Mars 16 million years ago, it created a crater that allowed the meteorite to escape. The 2-kilogram piece of Martian rock continued to orbit the Sun in an elliptical path until Earth captured it around 13,000 years ago. When it first touched down, it was in glacial Antarctica. It remained there until 1984 when a meteorite-hunting crew found it in the Allan Hills.
They assigned the sample the number ALH84001. Nobody initially thought it might have come from Mars. Ten years later, when scientists looked at ALH84001 more closely, they discovered that it was one of the so-called SNC meteorites, which are believed to have originated on Mars and not an ordinary meteorite. These types of meteorites all have minute amounts of gas that closely resembles the Martian atmosphere.
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