The tentative conclusion from the exploration is that Mars has never been anything like Earth in terms of life. Yes, there has been water, but very salty and acidic water which is unsuitable for life:
Ironically, I take some comfort in this. It would arguably be much more exiting to find life, or even signs of past life, but in some manner also depressing. The interpretation would have been that while life had originated on another planet, it had also succumbed. I'm a little pleased that such a doomsday verdict need not be true.
- Andrew Knoll said that the real question isn't whether there has been water on Mars, because surely there has been. The question is whether that water is habitable for life as we know it.
- Unfortunately for people who want to meet alien life, the prognosis is not good. Chemical and mineral evidence suggests that water on the planet is so salty and acidic that it wouln't support any organisms we know. "Water on Mars would be challenging for life as we know it," he said.
Anyhow, there's always Jupiter's moon, Europa, which has some sort of ocean beneath an icy crust.