For decades, Mars appeared to lack the first and most crucial ingredient: water. It was a frozen desert. However, the narrative changed dramatically in the early 2000s. Rovers like Spirit, Opportunity, and Curiosity transformed our understanding of Martian history. They discovered minerals that only form in the presence of liquid water, such as hematite and clays.
Four billion years ago, Mars was surprisingly Earth-like. Instead of the frozen desert we see today, it likely had: This is the best evidence yet for ancient life on Mars Life On Mars
Viking had three experiments:
The ethical debate will rage if we find extant (living) microbes. Do we study them in a lab, or leave them untouched in their natural environment? For decades, Mars appeared to lack the first