A color scan of the original computer printout of the "Wow!" signal as detected by the Big Ear Radio Observatory in 1977.
An astronomer thinks he's pinpointed the source of a mysterious radio signal from space: a passing comet that nobody knew about. But his colleagues said they're still skeptical of the explanation, noting that comets don't emit radio waves in the right way.
Antonio Paris, an astronomer at St. Petersburg College in Florida, recently published a paper in the Journal of the Washington Academy of Sciences saying the mysterious "Wow! signal," a truly bizarre radio signal detected almost 40 years ago, seems to match up with the location of a comet called 266P/Christensen that hadn't been cataloged at the time. (The comet was discovered more recently, in 2006. Originally, Paris' hypothesis was that a second comet might also be the culprit, one called P/2008 Y Gibbs.) Explanations for the Wow! signal have ranged from intermittent natural phenomena, to secret spy satellites, to, yes, aliens.
Others aren't so sure. "We do not believe the two-comets theory can explain the Wow! signal," Jerry Ehman, the astronomer who discovered the Wow! signal in 1977, told Live Science. [5 Times We Thought We Found Aliens]
The Wow! signal's name comes from just how striking and strange it was. The radio signal appeared on the night of Aug. 15, 1977, when it was picked up by the Big Ear radio telescope at The Ohio State University. It lasted 72 seconds. It was "loud" more intense than anything in the background sky that night. It was also a narrow-bandwidth signal; the range of frequencies it covered was small, similar to those of artificial signals. AM radio, for example, has channels that are only 10,000 cycles above or below the designated frequency on the dial. Further, the signal was at a frequency of about 1,420 megahertz (MHz), also called the 21-centimter line. That's the same frequency as radio waves emitted by neutral hydrogen gas in space. It's a region that is relatively free of noise from other objects, and one researchers involved in the search for extraterrestrial intelligence have been interested in for a long time because it could be used for interstellar transmissions.
The signal did not repeat, and subsequent attempts to find it proved fruitless. Ehman marked "Wow!" in red pen on a printout that shows the numbers representing the signal.
Back in 1977, the now-dismantled Big Ear telescope was looking for alien signals, in an early iteration of the search for extraterrestrial intelligence, or SETI. But no one expected to see anything like the Wow! signal, and the Big Ear telescope heard nothing like it again.
Without a repeat signal, it was impossible to tell what it was; even getting a precise location wasn't easy because the signal was short-lived. Ehman, now retired, told Live Science that, beyond a certain distance, it's hard to tell how far away a radio signal is coming from.
In his paper, Paris wrote that comets will, under certain conditions, emit radio waves from the gases that surround them as they zoom closer to the sun. According to the study, Comet 266P/Christensen was in about the right position on the right day in 1977. Paris first floated the idea in early 2016, and proposed a program of using radio telescopes to listen for the emission of such radio waves. [Face on a Comet: Ghostly Faces in Space]
The comet project had three phases. "The first phase was the hypothesis, which led to the second phase: Do comets emit 1,420 [MHz signals]? It appears yes, they do," Paris told Live Science.
In the third phase, set for 2018, Paris plans to explore the mechanisms of the emissions why comets should generate radio waves at that particular wavelength. Paris said little research has been done on the topic.
"There have been a handful of studies, but I suspect we are the first to specifically build a 10-meter radio telescope to specifically look at this type of solar system body," he said.
To see if a signal could have come from comets, Paris first used a radio telescope to look at the sky in the region of the Wow! signal. With this step, he wanted to see what the background looked like at the relevant frequency. He also checked two other comets to be sure that they did, in fact, emit radio signals at the 1,420-MHz frequency, and found that they did.
Then, in January, Paris directed the radio telescope to point at Comet 266P/Christensen as it passed through the region of the sky where the Wow! signal was seen. (Comet 266P/Christensen has an orbital period of about 6.65 years, and its apparent location in the sky will vary depending on where Earth is in its own orbit around the sun. The comet passed near, but not exactly, where the Wow! signal was about 2 degrees north of the Wow! signal location.
Yet several astronomers, including Ehman, think Paris is wrong about the comet. Ehman looked at Paris' study with Robert Dixon, who directs the radio observatory at The Ohio State University (Big Ear was destroyed in 1997). Two big issues are that the signal didn't repeat, and it appeared for such a short time. Ehman noted that the Big Ear telescope had two "feed horns," each of which provides a slightly different field of view for a radio telescope. [5 Huge Misconceptions about Aliens]
"We should have seen the source come through twice in about 3 minutes: one response lasting 72 seconds and a second response for 72 seconds following within about a minute and a half," Ehman told Live Science. "We didn't see the second one."
The only way that can happen, he said, is if the signal was cut off abruptly. A comet wouldn't produce that kind of signal, because the gases that surround them cover large, diffuse areas. Nor would the comet have escaped from the radio telescope's field of view that fast.
But Ehman isn't convinced it's aliens, either. There are many phenomena that show sudden appearances and disappearances of radio signals, including fast radio bursts (FRBs), which are mysterious radio bursts with hotly-debated astrophysical origins that generate irregular signals that last only milliseconds. If the the Big Ear picked up only the tail end of such an emission, the data could look similar to the Wow! signal, Ehman speculated.
"The issue with the feed horns is something no one can explain, including me," Paris said. "There is some data out there to suggest the issue is at the telescope end and not the phenomenon itself." So it's possible that the signal could have been caused by a glitch in the Big Ear telescope.
The other issue is the frequency of transmission. Paris said he has shown that comets can emit in that range, but Seth Shostak, a senior astronomer at the SETI Institute, is skeptical. Shostak used to study emissions from neutral hydrogen in the 1,420-MHz range, and is less sure the emission would look right. Comets may not generate enough hydrogen to make a bright enough signal like Wow!.
"I don't think anyone ever found such emission from comets," Shostak told Live Science.
Originally published on Live Science.
Go here to read the rest:
Comet Likely Didn't Cause Bizarre 'Wow!' Signal (But Aliens Might Have) - Live Science
- Comet - Wikipedia, the free encyclopedia - November 21st, 2013 [November 21st, 2013]
- Comets - The Nine Planets - November 21st, 2013 [November 21st, 2013]
- Comets - Astronomy For Kids - KidsAstronomy.com - November 21st, 2013 [November 21st, 2013]
- Views of the Solar System: Comets - November 21st, 2013 [November 21st, 2013]
- Comets (extra footage) - Video - November 21st, 2013 [November 21st, 2013]
- Solar flare update. 6 comets! Nov 28th ISON perihelion! - Video - November 21st, 2013 [November 21st, 2013]
- Comets game 2end goal - Video - November 21st, 2013 [November 21st, 2013]
- Missouri Comets vs. Milwaukee Wave - Video - November 21st, 2013 [November 21st, 2013]
- Football: Comets Advance Past Momence - Video - November 21st, 2013 [November 21st, 2013]
- Caliber Cheer Comets Nov 9 2013 - Video - November 21st, 2013 [November 21st, 2013]
- Two Comets Are About to Fly By Mercury | NASA Space Science HD Video - Video - November 21st, 2013 [November 21st, 2013]
- Comets win on tiebreaker - December 20th, 2013 [December 20th, 2013]
- Comets fend off Wildcat attack - December 20th, 2013 [December 20th, 2013]
- Free throws bring Comets down - December 20th, 2013 [December 20th, 2013]
- Comets continue solid play on their home ice - December 20th, 2013 [December 20th, 2013]
- Comets Beat Heat 4-2 - December 20th, 2013 [December 20th, 2013]
- Comets in the Community - December 20th, 2013 [December 20th, 2013]
- Comets pick up third straight win over Heat - December 20th, 2013 [December 20th, 2013]
- Comets Welcome Back Old Rival - December 20th, 2013 [December 20th, 2013]
- Comets Cool Abbotsford 4-2 - December 20th, 2013 [December 20th, 2013]
- Comets – Facts and Information about Comets | Space.com - December 20th, 2013 [December 20th, 2013]
- Comets v Wave 121313 Highlights - Video - December 20th, 2013 [December 20th, 2013]
- Highlights - Comets vs. Monsters 12/15/13 - Video - December 20th, 2013 [December 20th, 2013]
- Weekly Space Hangout - Preventing Asteroids, More Comets, Worldview Balloon - Video - December 20th, 2013 [December 20th, 2013]
- Pens 1 - Comets 0 - Video - December 20th, 2013 [December 20th, 2013]
- Milwaukee Waves Cheap Shot Vs. Missouri Comets - 12.13.13 - Video - December 20th, 2013 [December 20th, 2013]
- Hometown Nights - Tarso Miller and the Wild Comets - Video - December 20th, 2013 [December 20th, 2013]
- Hangout with Comets Nova and Deathlyhall - Video - December 20th, 2013 [December 20th, 2013]
- Comets vs St. Louis Ambush - Video - December 20th, 2013 [December 20th, 2013]
- Shake, Rattle and Roll Bill Haley and His Comets - Sheet Music - Easy Alto Sax Version - Video - December 20th, 2013 [December 20th, 2013]
- Comets Shut Out Heat 3-0 - December 21st, 2013 [December 21st, 2013]
- Administration - December 21st, 2013 [December 21st, 2013]
- Bill Haley And His Comets ' R-O-C-K' 78 rpm - Video - December 21st, 2013 [December 21st, 2013]
- Bill Haley And His Comets ' The Saints Rock 'N Roll' 78 rpm - Video - December 21st, 2013 [December 21st, 2013]
- Nicklas Jensen's Shootout Winning Deke 12-15-13 - Video - December 21st, 2013 [December 21st, 2013]
- Missouri Comets Night with Miles - 12.13.13 - Video - December 21st, 2013 [December 21st, 2013]
- 12/13/13 Comets 5 vs. Senators 2 - Video - December 21st, 2013 [December 21st, 2013]
- Comets rock Bulldogs for first win - December 22nd, 2013 [December 22nd, 2013]
- Comets Deposit Life's Building Blocks Across the Cosmos!(Dr.Ruehl) - Video - December 22nd, 2013 [December 22nd, 2013]
- Comets beat AHL rival Abbotsford again with shutout - December 23rd, 2013 [December 23rd, 2013]
- Comets Win Streak Grows to Four Games - December 23rd, 2013 [December 23rd, 2013]
- Comets Corner: On the Mask - December 23rd, 2013 [December 23rd, 2013]
- 'Comets of the Centuries': 500 Years of the Greatest Comets Ever Seen - December 23rd, 2013 [December 23rd, 2013]
- Hackensack High School (NJ) Football Home - MaxPreps.com - December 23rd, 2013 [December 23rd, 2013]
- Little Comets - Isles (Music Video) - Video - December 23rd, 2013 [December 23rd, 2013]
- Comets Have Two Players on MISL Team of Week - December 25th, 2013 [December 25th, 2013]
- ONE FOR THE RECORD DECEMBER 20 2013 21 FUKUSHIMA COMETS EARTHQUAKES NMR GZ PAUL AND BP - Video - December 25th, 2013 [December 25th, 2013]
- Comets in the Community: Christmas at St. Luke's - December 26th, 2013 [December 26th, 2013]
- Best comets of last 500 years - December 26th, 2013 [December 26th, 2013]
- STRANGE EVENTS In 2013 Earthquakes, Mass Animal Deaths, Extreme Weather, OORT Cloud Comets - Video - December 26th, 2013 [December 26th, 2013]
- Utica Comets " 'Twas the Night" - Video - December 26th, 2013 [December 26th, 2013]
- Missouri Comets vs. Rochester Lancers - Video - December 26th, 2013 [December 26th, 2013]
- Chasing Comets: In search of secrets about our origins - Video - December 26th, 2013 [December 26th, 2013]
- DREAM X2 COMETS/STARS FLYING OVERHEAD, MASSIVE SONIC BOOMS EARTH HIT POSSIBLY. - Video - December 26th, 2013 [December 26th, 2013]
- What are comets? - Video - December 26th, 2013 [December 26th, 2013]
- Game Preview: Syracuse Silver Knights at Missouri Comets and St. Louis Ambush - December 27th, 2013 [December 27th, 2013]
- Clark's performance boosts Clayton over Moss Point - December 27th, 2013 [December 27th, 2013]
- Gameday: Comets vs. Binghamton - December 27th, 2013 [December 27th, 2013]
- Comets Battle for First Place - December 27th, 2013 [December 27th, 2013]
- Gameday: Comets vs. Hamilton - December 28th, 2013 [December 28th, 2013]
- Comets fall to Senators - December 28th, 2013 [December 28th, 2013]
- Comets end winning streak - December 28th, 2013 [December 28th, 2013]
- Comets vs Syracuse Silver Knights - Video - December 28th, 2013 [December 28th, 2013]
- Winning Comets Soccer - Video - December 28th, 2013 [December 28th, 2013]
- Comets Lose in Final Minutes - December 29th, 2013 [December 29th, 2013]
- CometsTV: 12-27-13 Utica Comets vs. Binghamton Senators Highlights - Video - December 29th, 2013 [December 29th, 2013]
- Comets knock off Aquin for second time this season - December 31st, 2013 [December 31st, 2013]
- Comets fall after late rally - December 31st, 2013 [December 31st, 2013]
- CometsTV: 12-28-13 Utica Comets vs. Hamilton Bulldogs Highlights - Video - December 31st, 2013 [December 31st, 2013]
- Comets Corner: Kellan Lain - January 1st, 2014 [January 1st, 2014]
- Comets Welcome New Year - January 1st, 2014 [January 1st, 2014]
- Comets Media Game 2013 - Video - January 1st, 2014 [January 1st, 2014]
- 1957 AMI H200 playing Bill Haley and his Comets Rock Around The Clock. - Video - January 1st, 2014 [January 1st, 2014]
- 7 Amazing Christmas Kinder Surprise Eggs SMURFS cars, comets Unwrapping Review Chocolate Easter Toys - Video - January 1st, 2014 [January 1st, 2014]
- Shootout - Dogs @ Comets - 12/2813 - END - Video - January 1st, 2014 [January 1st, 2014]
- Shootout - Dogs @ Comets - 12/2813 - Video - January 1st, 2014 [January 1st, 2014]
- Catonsville girls basketball shows promise for another strong season - January 2nd, 2014 [January 2nd, 2014]
- Gameday: Comets vs. Lake Erie - January 2nd, 2014 [January 2nd, 2014]
- Comets Kick off New Year with Exciting Win - January 2nd, 2014 [January 2nd, 2014]
- Comets Remain Hot at Home with 3-2 Decision over Lake Erie - January 2nd, 2014 [January 2nd, 2014]