It may seem like science fiction, but some downright respectable scientists are gathered around radio antennae, waiting for messages from alien worlds.
And while other scientists scoff at stories of space aliens crash-landing in Roswell, New Mexico, still more are serious about alien television and radio broadcasts being beamed across the galaxy.
"We think that the extraterrestrials are out there. In fact, personally, I think the galaxy probably has a lot of intelligent critters out there," said Seth Shostak of the SETI (Search for Extraterrestrial Intelligence) Institute. "And we're trying to find them by eavesdropping on their radio traffic."
SETI is home to the most ambitious alien-contact project, tuning into 28 million separate frequencies. Scientists searching for extraterrestrial intelligence scan the static of the heavens for a signal, something that might amount to a message that says: "We're out here!"
Unlike actor Charlie Sheen's on-screen excitement at the discovery of an alien radio signal in the 1996 movie "The Arrival," in real life it's likely to be a computer that finds the signal.
"This is not like in the movies, where Charlie Sheen can sit next to the telescope with a bunch of loudspeakers and suddenly he hears (a sound) coming over the loudspeakers," Shostak says. "The computers are in fact monitoring the receiver, monitoring the 28 million channels."
Close to a breakthrough
But even Shostak has had his Charlie Sheen moment.
"There was a signal that we picked up in Australia that was passing all the tests for a few hours, and everybody was getting a little bit excited about that," he recalls. "I remember that I couldn't sit down. I just kept pacing around."
In the end, it was a false alarm, perhaps a stray satellite signal. Could it have been alien contact? No one knows. But about a dozen other scientific searches continue.
"If there are two or three places in our solar system that have life, life is rampant. Life is not a miracle. It's a statistic, something that happens all the time," Shostak explains. "So if you're getting a lot of life hooked up in the galaxy, maybe some of it's smart enough to build a radio transmitter."
While Shostak searches for alien radio broadcasters, he doesn't ever expect to have a personal encounter. The closest ones are light years away and even aliens have to obey the laws of physics, he says.
"If you want to make that trip in 10 years or less, the amount of energy your rocket's going to burn up is the amount of energy the United States uses in a century," Shostak says.
If Shostak is right, there may well be extraterrestrials out there. Someday there may even be interplanetary chat. But forget that close encounter, arrival and contact stuff. Shostak says it's just not fuel-efficient.