While you were soaking up the sun at your Memorial Day barbecue, hopefully you raised a glass to the Mars Phoenix Lander. It was the one-year anniversary of the plucky rover's landing on the red planet yesterday and its findings of subterranean ice — and perhaps liquid water — marked a historic year in the search for Martian life.
The Phoenix Lander wasn't intended to search for life itself, but the images it sent home in June of shining ice just below the planet's surface gave a huge boost to the hope that life could have existed on Mars. The idea that life could still exist on Mars got a boost in January, when a NASA team released its study of methane plumes emanating from below the surface.
On Earth at least, methane is usually released by living organisms, and a study released in March suggested that Mars' gigantic mountain, Olympus Mons, could only have formed in the asymmetrical manner it did if clay sediments were involved—that means water, and perhaps life.
The fact that Mars has natural features that appear to be formed by water is nothing new. But the formations found within the last year, like alluvial fans and river valleys running 20 meters deep and formed a mere 1 billion years ago, is certainly news. Most scientists thought there was little major hydrological activity on the Martian surface after about 3.5 billion years ago. So this year's findings, thanks to the Spirit and Opportunity rovers, raise hopes that water flowed freely across the planet more recently and perhaps some kind of life existed alongside it.
And last week, just before the Phoenix's touchdown anniversary, Science published a new paper covering Opportunity's finding that the giant Victoria Crater was carved by water, adding more evidence that the wet stuff covered huge areas of Mars and not just isolated pockets.
The last 365 days provide a heap of tantalizing clues that life once lived one the red planet and could still exist below the surface. The next step is to move from missions like the ones currently deployed—which hunt for ice, water and other evidence that life could have existed—to missions intended to directly seek out this new life. New rovers by NASA and the European Space Agency would go directly after spots that look promising for life, like the methane plumes.
It'll be a few years before the next generation of rovers reach the Martian surface, but if your curiosity can't wait, go exploring yourself on Google Mars.