Martian Valleys Likely Caused by Ancient SnowfallMartian Valleys Likely Caused by Ancient Snowfall
<p style="text-align: center;"></p> <p>First it was fresh <a href="http://news.discovery.com/space/toboggan-tracks-on-mars-130612.htm" target="_blank" rel="nofollow">toboggan tracks</a> on Mars, now it’s evidence that it snowed there, albeit a billion years ago.</p> <p>Rather than water bubbling up from