Strange Greenhouse Gas Warmed Ancient Mars

At first glance, Mars' 500-mile-long Nanedi Valles looks like the Grand Canyon, with its steep-sided walls and plunging crevasses, two features that indicate a history of water

However, the Mars we know today is one of freezing temperatures, arid conditions and, most importantly, a paper-thin atmosphere — all combined to create a hostile environment seemingly defiant of any life at all, let alone water

Scientists have floated the idea that meteorites assaulted the Red Planet billions of years ago, generating steam atmosphere to create the landscapes like the Nanedi Valles, a large valley that stretches 1.5 miles wide in some areas. However, it's more likely that an unusual greenhouse gas raised the planet's temperature to allow for flowing water. Read more...