How to send a message to another planet

Rendez-vous IN 2029 the inhabitants, if any, of the planet GJ 273b will receive a message that will change their lives forever. Encoded in radio signals emanating from an innocuous-looking blue-green planet 12.4 light-years away, will be tutorials in mathematics and physics, followed by a burst of music. The import of the message, however, will be clear: "Let's talk." Or so Douglas Vakoch hopes. For on November 16th Messaging Extraterrestrial Intelligence (METI), the group that he heads, and the...