As on date, scientists have identified around 300 meteorites from Mars, and some of them (through their chemical composition) have shown proof of water on the planet. Still fewer seem to carry something extra – signatures of Martian life! Or do they? Nearly four decades have passed since the most significant one among such meteorites was found, and scientists haven’t reached a consensus yet!
The Martian meteorite Allan Hills 84001 (ALH84001) was found on Alan Hills, Antarctica, in 1984. Though this four-billion-year-old meteorite landed on the Earth only around 13,000 years ago, ALH84001 was ejected from Mars by an impact event about 17 million years back! Chemical analysis showed that it was exposed to water on Mars.
But it was in 1996 that ALH84001 burst into public consciousness – when a team of scientists announced that they had found fossils of tiny bacteria-like life forms, called nanobacteria, in it! But this finding was (and still is) hotly debated.
Many argue that the so-called fossils aren’t fossils at all but simply organic material (compounds of carbon and hydrogen, which may also contain oxygen, nitrogen and other elements) that can form without the involvement of living matter, and that nanobacteria itself exists only in theory, not in real life.
Another Martian meteorite that landed in Egypt in 1911, called the Nakhla meteorite, also had carbon-rich structures inside which could be the products of bacteria. But this too is considered insufficient evidence for life on Mars for similar reasons.
Picture Credit : Google
