For a few spectacular moments last Tuesday, people in Asia watched in awe as day turned dark as night. They saw a total eclipse of the sun, which happens when the moon passes directly in front of the sun, blocking its light.
Seeing an eclipse is like watching bites being taken out of a cookie. The moon's shadow passes over the sun until all that remains is a white glow around a dark circle.
The only safe way to view an eclipse is through filters. But once the sun is totally darkened, it's O.K. to gaze at one of nature's greatest sights.