As predicted last week, the major announcement from NASA today is that the Mars Reconnaissance Orbiter (MRO) has discovered that liquid water flows on present-day Mars. And while it may only be a seasonal flow, its mere existence has scientists excited. (The original press release can be found here)

The MRO contains a spectrometer which allows it to look for signatures of different materials. In this case the orbiter detected minerals that had been recently deposited by flowing water. The mineral streaks darken during the warm seasons, suggesting a "spring thaw" and then reduce when the temperatures drop again.

This is the first time that scientists have been able to confirm the existence of liquid water on another planet. And as some people have already mentioned, on Earth everywhere we see liquid water - no matter the extremes of location or temperature - we have found some form of life. It is far too early to say if this is also true on Mars, but the discovery of water is a major step forward.

No doubt NASA will soon be planning out their next mission to Mars, and focusing on sending a lander to the site of these salty rivers. And we will all wait anxiously to see what it finds.