Are dry ideas of Mars all wet? It's starting to look that way.
As recently as even 2004, it was believed that possibly in the past, but certainly now, Mars was, or is, a bone-dry planet. Water could not have existed in any sufficient amount to sustain life, at least not in any recent times.
Various mapping missions though, showed significant traces of water-ice beneath the surface. As early as 2002, Mars Odyssey showed traces of ice underground, perhaps even a large amount. But we still hadn't detected anything at the surface to confirm these traces.
Mars Exploration Rovers sent back confirmations that water had not only flowed on the ground in the past, but there were also currently clouds of ice particles forming above Mars.
Phoenix, Mars Polar Lander, scraped up some soil and photographed some exposed water ice, right there on the surface at the south pole. It even managed to get a series of photos that show the ice sublimating away.
The latest confirmation is among the most cool. What if we had a way of digging a swimming pool sized hole in, say, some nondescript equatorial region of Mars, and took a look in that hole to see if we could find water? In the past month, some micro-meteors did just that, and Mars Recon Orbiter managed to take photos showing the ice fade.
So it's looking a lot like our near neighbor has had quite a wet history, we've just not been around long enough to make records of it ourselves. This is exciting in that it has a lot of ramifications for future manned exploration of the red planet.
Letting the days go by/water flowing underground
Into the blue again/in the silent water
Under the rocks and stones/there is water underground….