http://jlp.holodeck1.com/blog/
2005-03-20
Hourglass craters on Mars
ESA's Mars Express spacecraft is still orbiting around the red planet Mars and watching it closely using its High Resolution Stereo Camera (HRSC). A couple of days ago the orbiter has sent us some pictures of interesting hourglass-shaped craters. They are filled with flow features most likely formed by glaciers or "block" glaciers. Take a look at this photo:
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Hourglass shaped craters filled with traces of glacier