EDITORS PLEASE NOTE - RESENDING STORY FOR TECHNICAL PURPOSES<br/> <br />Could it be evidence that there was once life on Mars?<br/> <br />NASA's Curiosity rover has found spikes of methane in the Martian atmosphere, a gas that on Earth is strongly tied to life.<br/> <br />The rover also found organic chemicals in a soil sample collected by a robotic drill. They are the latest findings as NASA hunts for clues about the possibility of extraterrestrial life.<br/> <br />Last week, scientists determined that billions of years ago, a lake filled the 96-mile-wide crater being explored by Curiosity.<br/> <br />The finding was another hint that Mars, the planet most like Earth in the solar system, was once suitable for microbial life.<br/> <br />The rover has traveled around 5 miles since landing on Mars in August of 2012.<br/> <br />It has been exploring an area where rocks have been found containing water-deposited sediments to learn if the life-friendly environments actually existed long enough for life to evolve.
