The year was 1977, and many of us were captivated by the thought of extraterrestrial life. The silver screen brought us Star Wars (25 May 1977) and Close Encounters of the Third Kind (16 November 1977).
In-between, on the evening of 15 August 1977, a telescope in Ohio captured the first-and-only radio signal that might have originated from intelligent life.
The Ohio State University (OSU) Big Ear radio telescope had detected what we call the Wow! Signal about 11:16 p.m. EDST.
But what was the Big Ear radio telescope? And what was it listening for?
In 1959, two Cornell University physicists hypothesized that extraterrestrial life might try to communicate via radio signals because they are “cheap to produce, don’t require much energy and travel vast distances across space.”
But what on frequency? To that question, Philip Morrison and Giuseppe Cocconi answered “hydrogen.”
Hydrogen is the most common element in the universe. Zap a hydrogen atom and it will resonate at a particular rate: 1420 megahertz (MHz). So [also] look for something loud, something that would catch our attention.
Globally, scientists agreed with the hydrogen hypothesis. They made 1420 MHz a protected frequency.
That was the frequency of the Wow! Signal (precisely, 1420.4556). When he saw the anomalous signal on the computer printout, Dr. Jerry E. Ehman scribbled “Wow!” and circled the sequence (6EQUJ5). The pattern reflected the shape and volume of a signal of intelligent origin, as hypothesized.
“I had never seen any signal that strong before,” Jerry says. “U” … means about 30 times louder than the ordinary noise of deep space. That’s kind of a “Hello!” level.
[The signal] lasts for about 72 seconds, which is exactly how long a particular patch of sky would be in focus due to the rotation of the Earth. This means the signal appeared to move with the sky, so it wasn’t likely to be of terrestrial origin.
The Wow! Signal originated from the direction of Sagittarius. It “is still considered the best SETI candidate radio signal,” according to Alberto Caballero, a science communicator who coordinates the Habitable Exoplanet Hunting Project.
But it’s not been replicated, thus breaking a cardinal rule of scientific “truth.”
In 2005, Michael Brooks wrote in New Science:
The fact that hundreds of sweeps over the same patch of sky have found nothing like the Wow signal doesn’t mean it’s not aliens. When you consider the fact that the Big Ear telescope covers only one-millionth of the sky at any time, and an alien transmitter would also likely beam out over the same fraction of sky, the chances of spotting the signal again are remote, to say the least.
In 2012, the National Geographic Channel and Arecibo Observatory packaged more than 10,000 Twitter messages (#ChasingUFOs) as well as videos from celebrities like Stephen Colbert. On 15 August 2012, they “beamed” the data into space as a “big Hello! from Earth.”
It’s 45 years later, and scientists are still pondering the origins of the Wow! Signal.
On 02 May 2022, the International Journal of Astrobiology published research by Caballero which identified “a potential Sun-like star” that might be the source of the Wow! Signal. We know it as 2MASS 19281982-2640123; this star is located about 1,800 light-years from Earth.
The Big Ear radio telescope
In 1963, OSU developed the Big Ear radio telescope specifically to search for “extragalactic radio sources.” Built by students, it was located at Ohio Wesleyan University in Delaware, Ohio, until 1998.
Initially, the telescope focused on wideband radio sources (Ohio Sky Survey). Almost all celestial radio sources such as galaxies or stars are wideband sources. Two of those identified radio sources were “the most distantly-known quasars at that time.”
In 1973, OSU converted the telescope to narrowband radio sources, those more likely to arise from intelligent life.
In 1997, Dr. Ehman wrote:
Use of the Big Ear would quickly result in our achieving the record for the longest continuously-running survey of narrowband radio emission …as described in the “Guinness Book of World Records”…
[That was the same year that very large radio telescopes entered the public consciousness via the movie Contact(11 July 1997).]
In 1998, developers demolished the Big Ear radio telescope after purchasing the land on which it was located to build homes and an 18-hole course.