Note to "Chicken Little" fans: The sky's not falling (we hope!), but it will go completely dark in some parts of the world on March 29.
That's because the Earth, moon, and sun will align, resulting in a total solar eclipse.
It's an event that occurs only once every two or three years. What happens is that the moon passes between the Earth and sun, blocking the sun from view and casting a shadow on Earth.
If you live in Brazil, northern Africa, Turkey, or central Asia, you'll have a front-row seat. The sun will disappear from view for about four minutes, and only the sun's outer atmosphere, called its corona, will be viewable, often appearing dark purple.
In other parts of the world such as Europe, stargazers can enjoy a partial eclipse. (Those in the US, though, will have to wait. The next solar eclipse you can view doesn't happen until 2017.)
Although the sun is much larger than the moon, it is eclipsed by the smaller object because the sun is so much farther from Earth than the moon. This is similar to holding your hand in front of your eyes to block a distant, larger object from view.
Try this on your own. Find a large object like a bike or car and stare at it. Next, bring your hand in front of your eyes to block your sight. What happens? The object disappears behind your hand. In a sense, your hand eclipses that larger object in the same way the moon eclipses the larger sun.
See what else you can eclipse performing this simple experiment.