What kind of evidence has the Mars orbiter found in terms of possible life?
Complex clay molecules have been detected on Mars in formations that imitate river deltas here on Earth. These clay molecules take time and pressure to form at the bottom of lakes and oceans. Their presence indicates that there was standing water at some time in Mars’ past. The current thinking is that this was billions of years ago. No evidence of life has been found, but it cannot be ruled out. This discovery was made and published this month from data gathered over weeks and months. You can find out more at the link below. I hope this helps. Sources: http://www.nasa.gov/mission_pages/MRO/news/mro-20080716.
