Just 12 people have walked on the Moon and they’ll know better than anyone just how big (or small) the place is. But we can make some comparisons with things on Earth to get a measure of the Moon.
A total solar eclipse will be visible across parts of the United States Aug. 21, treating amateur and professional astronomers alike to sights similar to this NASA’s Solar Dynamics Observatory ultraviolet image of the moon eclipsing the sun on Jan. 31, 2014.
(NASA)
For centuries, scientists have known when and where eclipses will be visible. They pack their bags, head for the line of totality and hope for the best – which doesn’t always happen.