Astronomer Frank Drake first pointed a radio telescope toward the skies in 1960 in a deliberate search for alien signals, and SETI, the search for extraterrestrial intelligence, began. Since then, astronomers have spent many thousands of hours searching for alien signals.
In 1965, Ohio State University
built the Big Ear radio telescope specifically to search for alien transmissions.
On the night of August 15, 1977, astronomers ran an automated scanning program
in a region of the constellation Sagittarius. At 10:16 p.m., the telescope
detected a 72-second burst of radio noise in the frequency range astronomers
thought the best to search for alien signals. The next morning, astronomer
Jerry Ehman reviewed the computer log and noticed a signal that was 20 times stronger
than the background noise. He circled that portion of the computer printout and
wrote “Wow!” in the margin.
Although astronomers have
repeatedly searched that area of the sky looking for a repeat of the Wow
signal, it has never come again. Over the years since, astronomers hunted for
any possible non-alien explanation for the signal without success. Recently,
the director of the Habitable Exoplanet Hunting Project, Alberto Caballero,
stated "The 'Wow!' signal is still considered the best SETI candidate radio
signal.” He began a search of the region of the sky where the signal originated
looking for likely candidate stars.
The "Wow!" signal. Credit SETI Institute
He searched for stars similar to our sun in size, age, and brightness that might host Earth-like planets. He examined data collected by the European Space Agency’s Gaia mission which is creating a map of more than a billion stars with unparalleled precision. He found 66 candidate stars similar to our sun.
Astronomers must now examine those
stars to see if any possess Earth-like planets orbiting them. This process may
take a while, but if the Wow signal came from an alien race, this may be our
best chance to discover another intelligent civilization. At such great
distances to these stars, back-and-forth communication may be impossible. But,
at least we’d know we’re not alone in the universe.
Each month, I write an astronomy-related column piece for
the Oklahoman newspaper. After it is
published there, I post that same column to my blog page.
This is reprinted with permission from the Oklahoman and www.Oklahoman.com.
