Freshest Mars Rock Contains Evidence for Water
A meteorite that fell in Morocco last year might contain the freshest evidence for water on Mars, according to a study published in Science. The meteorite, named Tissint after the town nearest its landing site, was identified as a Mars rock in January. Now, Hasnaa Chennaoui Aoudjehane and her colleagues report that Tissint contains evidence of Martian soil — and that soil appears to have been altered by water.
But Tissint is special in that it is fresh. Eyewitnesses saw it fall to Earth at 2 a.m. on July 18th, 2011, and, because the Moroccan desert is dry and rainless, Tissint likely touched no water during the 2 months it took to recover all the pieces. This makes Tissint the freshest, least-contaminated sample of Mars that we have. So if Tissint records evidence of liquid water, it’s Mars’s water — not Earth’s. Aoudjehane and her team believe they see just that because when they performed chemical analyses of veins in the meteor, they found evidence of melted soil, perhaps melted by the heat of the impact. The chemical signature they found could only be explained by water interacting with the soil at some point before the rock was blasted off Mars some 700,000 years ago.