Here you go (slightly edited for copyright reasons):
Contact: Searching for life beyond Earth
Gannett News Service
ARECIBO, Puerto Rico – Call it a close encounter with what promises to be
the most important scientific discovery of all time.
Midway through the midnight shift at the world’s largest radio telescope,
astronomer Jill Tarter picked up what appeared to be a signal coming from a
small star named HD119850 .
There was no mistake. The beacon came in loud and clear at 1535- MHz on
the telescope’s radio dial.
Yet it matched nothing in the computer’s database of known terrestrial noise:
cellular telephones, pagers, radars and satellites that often masquerade as
broadcasts from alien beings.
What’s more, a backup telescope in England was hearing the same beacon
–a clear sign the signal was not salsa music from a San Juan radio station
bouncing back off the atmosphere.
Tarter, the real-life inspiration for the character played by actress Jodie
Foster in the movie “Contact,” took immediate notice and a long drink from
an oversized coffee mug.
“You may be here for something important,” she said.
Tarter, 55, is chief scientist with the SETI Institute of Mountain View, Calif.,
a nonprofit, privately financed group that carries out a Search for
The signal that got Tarter’s attention came from a star 106 trillion miles
away from the Arecibo control room, a bland computer lab with off-white
walls and worn linoleum floors.
All the “listening” is done by computers that scan 28 million radio channels in
search of unmistakable, repetitive artificial signals from other solar systems.
The problem is distinguishing what could be an alien call from the growing
cacophony of terrestrial noise. An increasing gaggle of satellites above Earth
swamp the airwaves with signals for cell phone conversations and TV
programs. Radio stations broadcast constantly, and military and civilian
radars scan the skies for enemy intruders and commercial airliners.
Here’s how it’s done: Should a promising signal pop up, SETI computers first
compare the beacon to a catalog of known local noise. Any signal that
matches is discarded automatically. But if the beacon is unfamiliar, a second
radio telescope at Jodrell Bank near Manchester, England, swings into
If Manchester radio telescope doesn’t detect the suspect signal, then the
beacon isn’t coming from a distant star: It’s local Puerto Rican noise that
hasn’t been catalogued.
But if the signal is strong enough to be picked up thousands of miles away
in England, too, then the beacon is put to another test.
An alien signal truly coming from a distant star would arrive in the United
Kingdom at a slightly different frequency than it would in Puerto Rico. It also
would drift just a bit on the radio dial.
That’s because Earth is rotating, and the telescopes in Puerto Rico and
England are widely separated.
Those subtle differences are predictable enough to be calculated with great
precision, providing a mathematical way to make certain that Earthly jabber
isn’t mistaken for a message from afar.
The suspicious beacon that startled Tarter passed the first two alien signal
tests. On cue, the huge Arecibo telescope automatically began to swing a
few degrees, pointing not at HD119850 but at blank sky, in yet another test.
A true signal from ET would disappear, a result of the telescope being aimed
away from the target star. If it persisted, then it couldn’t be coming from the
far-off star because the telescope no longer was pointed at it. It would have
to be local interference.
This time, it vanished.
And when the British telescope nodded away from the target, the beacon
disappeared there, too. Maybe, just maybe, Tarter was on to a most
But SETI computers decided the signal had not been the real thing. That
was it. The show was over.
Outside, the grinding of telescope gears meant the computers were moving
on to the next star on a preprogrammed target list.
Tarter slumped back in her chair, a bit deflated.
What initially had been a strong signal, she said, had faded. If aliens were
phoning, the volume on the telephone here on Earth wasn’t high enough to
hear the second ring.
“Maybe that was ET shouting once and never again,” she said.