Picture proves that water once flowed on Mars
NASA's Mars rover Curiosity has found evidence that water once flowed on the Red Planet, sending back pictures of bedrock that suggest a fast-moving stream was once there. Although there have been previous signs that water once existed on Mars, the new images, which show pebbles that were rounded off, likely by water, are the most convincing evidence yet. NASA intentionally landed Curiosity inside Gale Crater near the Martian equator early last month because photos from space suggested there might once have been water in that area. The picture above shows Mars rock formations on the left and Earth's on the right side.