A sand dollar left on the beach at Georgia's Sapelo Island (by Julia Brownlee; courtesy NOAA)
When bleached white by the sun, sand dollars may vaguely resemble the silver coins for which they are named. They aren't money, however. They are skeletons.
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Multiple lightning strikes are shown in this time-lapse photograph (photo by C. Clark, NOAA Photo Library, NOAA Central Library; OAR/ERL/National Severe Storms Laboratory)
You've probably seen hundreds of lightning flashes. Scientists are still working to discover some of its elusive secrets, but here's the basic story:
Read moreVenus is closer to the Sun than Earth. Jupiter is farther away. It seems the two objects ought to be in opposite directions, so how can they appear close together in the sky?
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