The Mars rover Curiosity has been returning preliminary data of rock samples that suggest water may have covered parts of Mars at one time. Scientists are also claiming that the atmosphere, now 96% carbon dioxide and 0.1% oxygen, also used to be capable of supporting life. There is also no sign of methane, which is produced both in geological processes and by organisms as they digest nutrients.
Still, scientists are theorizing that the planet could have been hit by an object as large as Pluto that knocked all the atmosphere off of it (yet somehow didn’t knock Mars out of its orbit) and that there could have been not only water but life. Some are still theorizing that there is life below the surface.
As a Christian, I am going to take what may be an unpopular stance: I believe in the possibility of aliens. God can do whatever He wants, so if He wanted to create intelligent beings on other planets or just be really random and creative with the animals of one, that’s His business. That said, I think it’s a mark of near desperation to keep hunting for life when the temperature, atmosphere, and ecosystem of a planet cannot support it. I would be shocked if they found concrete evidence that there was ever life on Mars, much more so if there is still any.
Even if they found a thriving bacterial colony, however, I don’t believe that disproves the Bible in any way. The Bible never says we are alone in the Universe. It never says that we are the only creatures God created or that all the other planets are lifeless rocks. In fact, given the extraordinary odds against evolution (read here for a couple of the numbers), life on other planets would be more likely to prove God exists than that He doesn’t.
Whatever the case may be, God is God and we are simply us. While it’s fun to speculate about life on other planets, research theories and see what evidence is for or against them, or just imagine the possibilities, our focus should be on finding the Creator. Neither our position as His children nor His as Creator are changed by there being other life out there, so it is still He who deserves our worship.