The Arecibo message is an interstellar radio message carrying basic information about humanity and Earth that was sent to the globular cluster Messier 13 in 1974. It was meant as a demonstration of human technological achievement, rather than a real attempt to enter into a conversation with extraterrestrials.

The content of the Arecibo message was designed by a group of Cornell University and Arecibo scientists: Frank Drake, creator of the Drake equation, Richard Isaacman, Linda May, and James C.G. Walker. Carl Sagan and others also contributed.

The message was meant more as a demonstration of human technological achievement than a serious attempt to enter into a conversation with possible extraterrestrials.

As globular cluster M13, at which the message was aimed, is more than 25,000 light-years from Earth, the message, traveling at the speed of light, will take at least 25,000 years to arrive there.

By that time, the core of M13 will no longer be in precisely the same location because of the orbit of the star cluster around the Galactic Center. Even so, the proper motion of M13 is small, so the message will still arrive near the center of the cluster.