According to some ancient Mesopotamians, "The sun was put to shame" during a 14th century total solar eclipse. How can the moon, which is 400 times smaller than the sun, completely cover it? This video demonstrates the answer...

Studying spiral galaxies can make your head spin! With this video, find out how astronomers calculate a galaxy's rotational speed, and how the prediction that the outermost stars slow down does not seem to be true. The mystery may be...