Look out, extraterrestrials. Regular human beings — the same folks who struggle to figure out self-checkout lines at grocery stores — are now listening to your every move.

Astronomers at Adler Planetarium launched a website today that allows anyone with a computer to join in the search for possible radio signals from alien life. The site is SETIlive.org — SETI is an organization whose name stands for Search for Extra Terrestrial Intelligence.

Computers already monitor radio signals collected by a California-based array of radio telescopes. But researchers believe the computers can’t filter through the full spectrum of signals — many of which are just interference caused by satellites and cell phones — and humans may be more likely to identify what could be signs of alien life.

“Humans have this unique ability to pick out all sorts of complicated signals, even when it’s noisy,” said Adler astronomer Chris Lintott, who led the project. “Think about talking to a person in a crowded room. The plan is to search for signals from alien civilizations in a way that hasn’t been done before, which is to get human brains to look at data as it comes off the telescope live.”

The radio signals appear on the website as patterns, everything from an array of dots to a spaghetti-like swirl of solid and broken lines. The site provides a tutorial on how to differentiate common interference signals from unusual signals that might be worth investigating. If someone sees something intriguing, that person can tag it on their Web browser.

The telescope moves about every three minutes. But if a certain number of people — for now it’s about five —mark the same signal, the telescope will be directed back to re-examine the point the signal came from.

“This is what real alien hunting looks like,” Lintott said. “The pictures aren’t as pretty and it’s not as exciting as a flying saucer landing at your gate, but it is real science.”

All the stars being examined are in the Milky Way, a few thousand light years out. Lintott said, “We’re pointing deliberately at stars where we know there are planets and those planets have the right conditions to have liquid water. That allows us to up the odds.”

And it also allows us to retain supremacy — for now — over our electronics.

“The good thing about this,” Lintott said, “is if we do discover alien life, at least humans will discover it and not computers.”

rhuppke@tribune.com