I’m a bit late on this month’s What’s Up article, where I usually detail events like this, but I wanted to make sure that everyone was aware of today’s transit of Mercury.

A transit occurs when a planet interior to our own (Mercury or Venus) crosses directly in between the Earth and the Sun. What we see is a black disk crossing the face of the Sun over a period of several hours.

Venus transits the Sun in the summer of 2004

The transit begins at 2:12 p.m. EST, and lasts for about five hours.

Note: Do not observe the Sun without proper protection. Sunglasses don’t count. Only use approved solar filters when looking at the Sun, or better yet, rig up a simple projection system.

Projecting the Sun’s image onto a piece of cardboard

NASA’s Exploratorium has an article with instructions on how to view it safely. You may want to check out Larry Koehn’s animated simulation of the transit.