Download Big Ear receives `Wow! Signal,` August 15, 1977

Big Ear receives ‘Wow! Signal,’ August 15,
1977
Suzanne Deffree - August 15, 2016
Celebrating
60 years of EDN
In 1977, EDN was in its 21st
year. What else was happening
in 1977?:
• Apple Computer was
incorporated.
• The rings of Uranus were
discovered.
• Optical fiber was first used to
carry live telephone traffic.
• Star Wars was released.
• The Apple II went on sale.
• EDN published "Squeeze high
performance out of low-cost hybrid
data converters," by Paul Prazak.
• A New York blackout forced a
look at power systems.
• A TCP/IP test succeeded in
connecting 3 ARPANET nodes in
what would become the Internet
protocol.
• NASA launched Voyager 2.
• Also see this blog about
automated test systems in 1977.
Read all of our coverage of
EDN's 60th anniversary here.
An Ohio State University radio telescope known as The Big Ear received a radio signal that many
believe came in from deep space on August 15, 1977.
The telescope was located at Ohio Wesleyan University's Perkins Observatory, in Delaware, Ohio,
and was being operated as a part of a SETI (search for extraterrestrial intelligence) project. It was
fixed and used the Earth’s rotation to scan the sky. As such, the Big Ear could observe any given
point for just 72 seconds.
The signal was a strong narrowband radio signal detected by university professor Jerry R Ehman. It
lasted for the full 72 seconds and could not be detected again.
Ehman was reportedly so amazed at how closely the signal matched the expected signature of an
interstellar signal in the antenna used that he circled the signal on the computer printout and wrote
the comment "Wow!" on its side. (See image scan of the printout) The signal then became known as
the “Wow! Signal.”
Indeed, the Wow! Signal did closely resemble what researchers expected an extraterrestrial signal
would be. Its narrowband matched the telescope's antenna pattern, which indicated that it was at
least at a lunar distance and not from a nearer object as such a signal would have a wider pattern.
Its frequency was near the 1420 MHz hydrogen line, where radio transmissions are prohibited.
The signal's strength was 30 standard deviations above the mean background noise, showing that
the transmitter used a large amount on energy.
Also, the 72-second-long signal, being studied by the fixed telescope, gradually peaked for the first
36 seconds until the signal reached the center of Big Ear's observation window and then a gradually
decreased. As such, both the length of the signal and the bell shape of the intensity graph were
considered to correspond with a possible extraterrestrial origin.
Whether the signal was extraterrestrial in nature or not is debatable. Ehman, himself, has stated
doubts. But the Wow! Signal did stir much media coverage at its finding and why the signal could
not be located again is still pondered today as a great riddle of science.
Also see:
●
●
●
●
●
$51M radio telescope shoots for look at Big Bang
Light bending in space—Kepler meet Einstein
Roswell Incident is first reported, July 8, 1947
Ghost rocket UFOs are 1st reported, February 26, 1946
Mars Curiosity Rover: ChemCam laser-induced breakdown spectroscopy unveiled
●
NASA’s Deep Space Network
For more moments in tech history, see this blog. EDN strives to be historically accurate with these
postings. Should you see an error, please notify us.
Editor's note: This article was originally posted on August 15, 2012 and edited on August 15, 2016.