A magnified view of the meteorite from Mars, ALH84001. Ejected into space, it landed in Antarctica 13,000 years ago and was collected by scientists in 1984. The orange and black disk patterns are made of carbonate. The debate still rages over whether or not the meteorite contains evidence of microscopic Martian bacteria fossils. Credit: Kathie Thomas-Keprta and Simon Clemett/ESCG at NASA Johnson Space Center