Credit: NASA (Click for full size)
NASA just released some pretty interesting news this afternoon. The Mars Reconnaissance Orbiter (MRO) has been taking photos of the surface of Mars for many years, and scientists have seen what looked like gullies on the surface. But, they had no way to confirm whether those gullies were caused by water or just sand sliding down a slope, or by frozen CO2. There is still no way to confirm for certain that what we’re seeing was caused by flowing water on the surface, but evidence is starting to lean in that direction. These dark finger-like features have been seen changing shape before- but on the colder side of the slope that faces away from the sun most of the day. That would point toward the gullies being caused by frozen CO2. These new images are of features on the warmer sun-facing side of the slopes, meaning the likelihood of them being caused by flowing liquid water is far greater. The most important thing here is to remember that this is NOT confirmation of liquid water on the surface of Mars. It is, however, highly suggestive of liquid water on the surface of Mars. This is exciting news because if it is indeed liquid water, there’s a much better chance that microbial life might still exist. Another important thing to remember is that we already know water exists on Mars- we’ve seen it as ice, both directly (Phoenix lander) and indirectly (radar soundings from MRO indicating water ice below the surface). The key to life though, is liquid water.
As usual, Dr. Phil Plait has a very good explanation of all this on Bad Astronomy, so I recommend checking that out. The NASA article can be found here.
steve cross loves music and science 