Graffiti: we do it on trees, rocks, subway cars, and bathroom stalls. The most popular form of all is simply scrawling our initials, sometimes adding a heart and the initials of that special someone.
Now you can send your very own "Kilroy was here" to Mars — in digital form. The NASA spaceship Phoenix, slated to land on the northern polar region of Mars in May 2008, will carry a silica glass DVD encoded with messages from the likes of Carl Sagan and Arthur C. Clark. Until February 12, the Planetary Society's "Messages from Earth" program is collecting names that will hitchhike to Mars aboard that DVD. It costs nothing; just click here. Names will also be sent to the Moon aboard Japan's SELENE spacecraft. In this case, you can add a short message. The deadline for submissions is February 28.
One could be cynical and dismiss Messages from Earth as just another form of human narcissism, the equivalent of planting one's flag in the New World for England. But let's not be cynical. The fact that you can look up at the sky and think, "My name is THERE," is pretty cool. Just for a moment, it gets your mind away from the humdrum of daily existence and up to the infinite sky.