关于这张图
The trails have some curious features. Sometimes the clay gets pushed into a mound at the trail's end, as in this photo. Photo credit: NASA/GSFC/Cynthia Cheung To read a feature story on the Racetrack Playa go to: <a href="http://www.nasa.gov/topics/earth/features/roving-rocks.html" rel="nofollow">www.nasa.gov/topics/earth/features/roving-rocks.html</a> <b><a href="http://www.nasa.gov/centers/goddard/home/index.html" rel="nofollow">NASA Goddard Space Flight Center</a></b> is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft…
