Slashdot Mirror
Mars Harder and Colder Than Previously Thought
coondoggie writes "Turns out that the surface of Mars is stiffer and colder than previously thought. New observations from NASA's Mars Reconnaissance Orbiter indicate that any liquid water that might exist below the planet's surface and any possible organisms living in that water would be located deeper than scientists had suspected. NASA made the discovery while using the Shallow Radar (SHARAD) instrument on the Orbiter, which revealed long, continuous layers stretching up to 600 miles, or about one-fifth the length of the United States. The radar pictures show a smooth, flat border between the ice cap and the rocky Martian crust, NASA said. On Earth, the weight of a similar stack of ice would cause the planet's surface to sag. The fact that the Martian surface is not bending means that its strong outer shell, or lithosphere, a combination of its crust and upper mantle, must be very thick and cold."
On Earth, a similar stack of ice also weighs twice as much ... it's a questionable comparison from which to draw a conclusion without more information.
How do you turn ice into a breathable atmosphere for a planet? The atmosphere is 78% nitrogen and 20% oxygen. If you could extract oxygen from the ice, you're still missing 4/5 of your atmosphere. Then of course there's the issue of what happens to all that free oxygen. Oxygen is highly reactive and tends to, well, oxidize whatever it comes into contact with; that's going to scrub it out of the atmosphere. That means that you have to produce vastly more than you'd need just to fill an atmosphere, and that's why it took hundreds of millions of years after photosynthesis became common before Earth had anything like a breathable atmosphere.
No, life is not known to exist on Mars. Odds are good some spores made it from Earth, but that doesn't mean they'll catch on anything. A bacteria that never leaves spoil form is just something that takes a long time to die. So there might be life there now, but there's no indication that it'll be growing or reproducing any time soon.
Does that not mean that basic evolution means there is a good chance that bacteria on mars now exists that does not on earth? That would be a neat trick for a bacteria to be both on Earth and Mars.