Retired Princeton astronomer uses moon to send secret messages

Joseph Taylor’s not your ordinary retired Princeton astronomer. He won the Nobel Prize in physics in 1993 with his colleague Russell Hulse for detecting two pulsars that were orbiting each other.

27moon.1.600(A pulsar is a condensed chunk of matter left over from the explosion of a supermassive star, which shoots out energy into space.) In his acceptance speech for the Nobel Prize, he said he was equally motivated by the personal satisfaction of finding clever solutions as we was for broad scientific goals.

Now 74, he spends his retirement doing something called ‘moon bouncing’. “It’s possible, but it’s difficult,” he said. “If you succeed, it’s fun.” What he does is reflect radio signals off the moon with a ham radio, using a homemade antenna in his backyard. Most ham radio users do this by reflecting signals off the upper atmosphere of Earth, but Taylor uses the moon. In order to bounce off the moon, he says, “You need to have a very sensitive receiver, the biggest antenna that you can manage and as much power as is legal.” That’s why he had a 70 foot tall tower built on top of his garage.

He does this to communicate with other ham radio users, so first he sends out a signal using the radio shorthand ‘CQ’, meaning ‘Seek you.’ Then he waits for the replies. He’s received over 3000 replies from 900 people. When he’s not moon-bouncing, he still studies pulsars at Princeton.

from Science News

Image: Jim Wilson/The New York Times