2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017
Thursday, December 5, 2002|
|Scientists Say Mars was Never a Greenhouse|
(CNN) - The authors of a new study say that while enormous surges of water carved out sprawling networks of valleys on Mars eons ago, the young red planet was hardly a steamy greenhouse with long-lasting oceans, as some scientists have theorized.
Researchers with NASA and the University of Colorado say the canyons most likely were formed during brief bouts of torrential rains, when asteroid and comet chunks collided with Mars and unleashed frozen water.
They propose that the flurry of impacts produced periodic layers of hot debris that blanketed the surface, warming it above the freezing point of water for decades or centuries at a stretch.
"We envision a cold and dry planet, an almost endless winter, broken by episodes of scalding rains followed by flash floods," the researchers wrote Thursday in the journal Science.
(More info: CNN.com)
- posted by Alex @ 14:49 EST