But when the pieces are found all together, the picture becomes compelling. Their interpretation is very professional and careful. But there are other interpretations. There are people saying it is conclusive evidence. It is not that.
More evidence is the presence of carbon and hydrogen compounds.
Finding all of these close together in the carbonates is the most intriguing part of the story, Black said. Ever since the Mariner 9 and Viking Lander missions in the 1970s, he said, people have advocated that conditions on Mars were conducive to life. The two Viking Landers specifically were designed to look for biologic activity in Martian surface samples but found none. However, the experiment said nothing about the possibility of ancient life, he noted. The traces of life found inside, however, are perhaps a billion years younger.