The bricks of protein fall from the sky
The Murchison meteorite, a carbonaceous chondrite that fell in 1969, contains amino acids that formed in space, not in Earth soil.
Established2 min read
Murchison fell in Australia and was collected quickly. Inside: dozens of amino acids, including many that life on Earth does not use, and a near-equal mix of left- and right-handed forms. Biology here is almost purely left-handed. A contaminant from fingerprints would not look like that.
Later falls and sample-return missions (Ryugu, Bennu) keep finding organics and water-bearing minerals. Space chemistry builds amino acids on cold grains. That is not a cell. It is the pantry.
Caveats
- Amino acids are not organisms. The step from bricks to a replicator is unobserved.
- Some amino acids in meteorites can still be terrestrial contamination. The unusual ones and the handedness are the clean evidence.
Sources
- 1Kvenvolden K. et al.. Evidence for Extraterrestrial Amino-acids and Hydrocarbons in the Murchison Meteorite. Nature 228, 1970.