On Earth, such layered rock structures occur where there were once lakes. They record our planet's history and scientists are hoping that on Mars similar deposits may stretch back 3.5 billion years to a time when Mars was warmer and wetter and possibly alive. Mars has preserved for us, in its sedimentary rocks, a record of events unlike any other that occur on the planet today. Other scientists have greeted the findings with equal enthusiasm. It also tells us that our new Mars exploration programme needs the flexibility to follow up in a carefully thought-out manner.
Biologists say the confirmation of sedimentary rocks is a major step forward.
These findings add great weight to the view that in its early few hundred million years, Mars was wetter and warmer with a thicker atmosphere. Many scientists believe that life could have arisen just as easily on Mars as it did on Earth. Later, Mars turned colder, although some speculate that life may hang on in isolated wetter regions or below the surface. That evidence may be recorded in Mars' sedimentary rocks. Who knows, in just a few years from now, scientists may be able to land on those rocks and search for life.