School of H&S: UFOs and Little Green Men?

Physics professor discusses the search for life on other planets.  by Karin Fleming ’09

In 1974 scientists beamed their first message into space to communicate our presence to other civilizations in our galaxy. By now, the coded message, named after Puerto Rico’s Arecibo Observatory, from which it was sent, has traveled just 34 of the 25,000 years necessary to reach the star cluster at which it was aimed. The chances of intelligent life intercepting it are extremely slim (not to mention the tiny probability of humans being around to receive a response in 49,966 years). Yet it’s not the only serious scientific attempt to find out what other life forms might be out there.

This is one topic Luke Keller, an assistant professor of physics at Ithaca, covered in front of a packed house in a February talk he called “Searching for Extraterrestrial Life: Molecules, UFOs, and Little Green Men.” It was part of his department’s fifth annual Physics Café series and a featured event for the Ithaca Visitors Bureau’s weeklong Winter Recess festival for teachers.

Keller used a combination of astrophysics and chemistry to show the process by which stars, planets, and, eventually, life are formed. Biochemistry major Joshua Roaf ’10 was impressed by this blend of sciences. “I was expecting it to be more about astronomy,” says Roaf. “[Keller] brought a lot of chemistry into it too, which I thought made it more realistic.”

Keller also explained the Drake equation, which was created in 1961 by then Cornell University professor Frank Drake -- one of the authors of the Arecibo message -- as an imprecise but useful tool for estimating the number of possible extraterrestrial civilizations with which we might hope to communicate. Keller gave his audience remote control devices to register their input for the test. “[While the] Drake equation is not a part of actual research,” says Keller, “it offers a useful illustration of the many factors we should take into account when looking for life on planets around other stars. Using the equation helps narrow the places for astronomers to look.”

In a galaxy of 200 to 400 billion stars, as many as half of which are likely to have planets that developed like ours, there are many places to explore. “We’re trying to figure out,” says Keller, “what would be the most probable place to find life. The universe is a really big place; you can’t just search randomly.”