1,000-Star ‘Window’ a Galactic Eavesdropper

STANFORD — Scientists searching the heavens for a message from extraterrestrials are listening to radio waves in a 1,000-star “window” amid the galaxy’s estimated 300 billion celestial bodies.

They believe life forms in outer space might be operating radio beacons to attract the attention of other civilizations throughout the galaxies. But noise from gaseous clouds, cosmic debris and stars makes the effort to tune in on an “artificial” signal from extraterrestrials who may or may not be there, a long shot at best.

It is something like using a telescope to look for an ant in the desert, said Ivan Linscott, senior research associate in the Stanford University radio science group of the Space Telecommunication and Radioscience Laboratory.

In an effort to improve the odds of hearing from another world messaging through all that natural celestial noise, a Stanford team of electrical engineering graduate students has created a chip that increase the number of “microscopes” or radio channels that can be heard.

Antenna in Mojave Desert

The chip will be used in a system that reads information from an antenna in the Mojave Desert as it scans the skies for extraterrestrial signals, part of a NASA program called Search for Extraterrestrial Intelligence (SETI).

At present, SETI has only a receiver. No signals have been transmitted.

“Why bark in the woods when we don’t know what’s out there,” Linscott said, pointing out that SETI and NASA believe that it is not proper to deliberately announce our civilizations presence to outside, unknown cultures.

Focus on 1,000 Stars

The Stanford engineers, operating on a $500,000-per-year grant from SETI, chose to focus their scientific ears on a manageable 1,000 stars, listening through the microwave portion of the radio spectrum. The search is centered in the 1,000-star “microwave window” because it is logical that extraterrestrials trying to contact other civilizations would send their signals through the region of least interference.

The listening system, called a multichannel spectrum analyzer (MCSA), is reading signals one hertz wide to allow distinction between natural noise and artificial signals, Linscott said. The most narrow of natural signals is still 1,000 times broader than an artificial signal, so a one-hertz wide signal would be extraordinary and probably from an extraterrestrial life form, Linscott said.

Since the “microwave window” is up to 10 billion hertz wide, “we’re missing a lot,” Linscott said. “So the team created this chip to increase the MCSA’s capacity to 10 million channels, while decreasing its size and cost.”