According to the analysis of rock samples collected by the Mars rover Curiosity, ancient Mars had all the basic ingredients to support living microbes. http://www.nasa.gov/mission_pages/msl/news/msl20130312.html Exciting news!
I think we knew this. Dirt + flowing water means the place could have supported pumpkins and vine-ripe tomatoes. Nowdays, not so much.
Yeah, as soon as they discovered water I thought this was a given. It's cool that they're still continuing to gather more data, though. My least favorite thing about science is that, even if we can prove that life once existed on Mars, we'll never be able to see it. What I often wonder is this. If life did exist on Mars at one point, how far did it evolve? Microbes? Plants? Did Mars have oceans full of crazy Martian fish? If we ever make it to Mars and establish long-term colonization there, will we one day discover the fossils of an ancient Martian dinosaur?
Reading the story, what they found is unoxidized and partially-oxidized elements (iron, sulfur, phosphorus, etc) in Martian sedimentary rocks that could've served as an energy source for bacteria, like what we see in hydrothermal vents in the deep ocean. Of course to me this also indicates that there weren't microbes taking full advantage of the conditions or they'd have oxidized the elements to extract the energy. Not finding any signs of life does have some major benefits for Mars exploration. If we find any traces of life then there's almost no way we could put a human on the planet in the foreseeable future because of the risk of contaminating the environment with Earth bacteria, forever ruining some of the potential science.
Sorry, no. In science, just because something may be unsurprising given a trend in recent discoveries, it is not the same as being "a given." In particular, just because it was already known that important necessary chemicals and conditions were present for life as we understand it, it doesn't follow from that alone that there weren't other chemicals or aspects of the environment which might have precluded life. Indeed, the article says: Those are some of the new results. Also both promising and significant is: This is conformation that Curiosity is in the right spot to be exploring for evidence of life as we understand it. --- One reason scientists are still gathering data is because the existence of life at any point in the history of Mars is still not given.
It already has, with the debacle about Curiosities drill that didn't get re-sterilized properly. Under the mission rules they can't allow the rover to get near water for fear of causing a contamination from Earth bacteria. Finding life won't stop the exploitation of Mars, but it will throw up some major road blocks to human presence as scientists insist on a heck of a lot more remote sampling of the indigenous life before they dare risk contaminating any of it. The number of unmanned missions will go way, way up, as will the requirements of manned-mission sterilization.