Did Aliens Try to Call and We Missed It? The Wow! Signal and the Mystery of TYC 1220-91-1  

By John Michael Godier

It might be safe to say that the holy grail of questions we humans can ask about the universe is 'are we alone?'. So far, the answer, as far as we know, is yes. Seemingly backing this up, we have the Fermi paradox which states that if alien life exists, why don't we see evidence of it? Good question. On the other hand, we have the odds, which are overwhelmingly against us being alone given the sheer amount of stars, planets and galaxies present in the universe. But if there is life elsewhere in the universe, how much of it is intelligent? And if there is intelligent life, have we ever seen any indication of it? The answer is potentially yes, we very well may have. And I say that with science in mind rather than wishful thinking. But we shouldn't go overboard either.

One of the great mysteries of space science was the infamous Wow! signal of August 15, 1977. On that day, the Big Ear radio telescope, a project of Ohio State University from the early days of the SETI programs, detected a signal located in the constellation Sagittarius that looked very artificial, as in so artificial that it remains the best candidate we've ever seen for an alien radio transmission. So much so that the discoverer of the signal, Dr. Jerry Ehman, warns that while we should be careful not to draw vast conclusions from half-vast data, an alien origin remains the best technical explanation for the Wow! signal.

The reason it was such a good candidate is that the signal appeared consistent with what scientist's expected an alien signal to look like. As it turns out, we can narrow down just how an alien civilization wishing to communicate would do it. The electromagnetic spectrum is very noisy. If you go too low in the spectrum, you run into a lot of noise from astronomical objects and if you go too high in the spectrum you run into something called quantum noise which renders those frequencies useless. Only between 1 and 10 gigahertz do we have a window where the spectrum is clear and useful. This applies to us, but also to the aliens. The laws of nature are the same everywhere.

But there's more. Planetary atmospheres block out different areas of the spectrum through reflection and absorption. Earth's atmosphere has two areas in the spectrum where it's transparent. Visible light, which is why we evolved eyes to see, and coincidentally that 1 to 10 gigahertz gap. So if you want to signal someone, you need to make sure it makes it through a planet's atmosphere and you need to make sure it's on a frequency where someone might be listening. Luckily, there are several magic frequencies where an intelligence might look.

One of these is known as the hydrogen line or watering hole as it's informally known. It is located at a frequency of 1.42 GHz, the frequency at which hydrogen emits radio waves. The sound of hydrogen is everywhere in the universe, you hear it on that frequency anywhere you point your radio telescope and that makes the frequency noteworthy. So it stands to reason that if you're going to pick a frequency to get someone's attention, go with the one that stands out. The Wow! signal was also very narrow, smack in the middle of the watering hole, and did not appear to be a signal from earth bouncing back off an asteroid. In other words, it had all the hallmarks of an artificial alien signal and no suggested natural explanation has stood up. But there's a problem. The signal never repeated.

Multiple attempts to pick the signal up again over the years have all been unsuccessful. Further, when you look at the narrowband signal itself to see what the nature of it was, it was found to contain no data. If you will, it was just a blank signal that we detected for 72 seconds, though it may have lasted longer due to the fact that the telescope was scanning past it and was not stationary.

What could the Wow! signal have been? That remains unclear, but being me, I can't resist speculating.

One possibility is a beacon of some sort that functions like a lighthouse sweeping its beam across space at an unknown rate. This might be useful for an alien species for scientific or navigational purposes rather than as a means of contacting other species. Unfortunately, without knowing the period of such a beacon, which could well be centuries, we don't know when to look for the signal when it passes by again. Since radio telescope time is expensive and in high demand, it seems unlikely that we'll see it again for the foreseeable future.

Another possibility is radar. Humans on earth have used radio telescopes like Arecibo to emit radio waves to detect near earth asteroids. These signals are directional and do not repeat, so if aliens are listening in our direction, they would see a signal similar to the Wow! signal, only much weaker and on a different frequency if they caught us while we were detecting asteroids. It's entirely possible that the Wow! signal might have been aliens mapping the asteroids in their solar system, though it would seem silly to do that at the hydrogen line.

But the Wow! signal is not the only candidate for a bona fide alien radio signal. While the media seems willing to label every weird signal from space as potentially alien, the fact is the vast majority turn out to have natural origins. But one other signal that stands out was captured and described in a 2010 research paper and did not get much media attention. Unlike the Wow! signal, which had no obvious source, this signal originated from the vicinity of a star named TYC 1220-91-1. Like the Wow! signal broadcasting at the hydrogen line, this signal too was in a very special area of the spectrum, 4462.3 Mhz.

This frequency is arrived at by multiplying Pi by the hydrogen line, again a magic frequency that an intelligent species might locate a signal in if they wanted to say hello in a way that doesn't seem natural, but also wouldn't mess their own radio astronomers up by broadcasting on the hydrogen line. More, the star itself is interesting. It's similar to our own sun, just a little older and could have habitable planets around it. Unlike the Wow! signal, this one was caught and tracked in realtime and lasted ten seconds and showed all the characteristics of what is expected from an interstellar beacon. It was also a very strong signal, a factor of ten times the strength of the Wow! signal. But, like the Wow! signal, it did not repeat and unfortunately there does not seem to be much active monitoring of this star.

While it's impossible to read the mind of an alien race, we are in fact a technological intelligent species ourselves and there are certain things we do that aliens might detect. One of the misconceptions regarding us though is that our transmissions would be visible to an alien civilization. This idea was famously put forward in the movie 'Contact' when an advanced alien race detected a broadcast of Adolph Hitler opening the 1936 Olympics and broadcasted it back to us. But this is in reality highly unlikely. Our radio and television transmissions are weak, typically far less than 100,000 watts. If we took our current equipment to the nearest star system and pointed it towards earth, we wouldn't be able to detect ourselves in most radio frequencies. There are exceptions however, such as our radar that can travel much more distantly and powerful signals we've sent out from Arecibo intentionally sending messages to alien races. The problem is, we didn't repeat the signals. Why? Not enough money and telescope time. We may well be someone else's Wow! signal.

So that begs a question, if we're not willing to pay for a full-time beacon to get the attention of aliens, then why would they? This has led to an interesting proposition put forth by physicists Gregory and James Benford. The twin brother scientists have suggested that aliens might repeat their signal periodically to save energy rather than  maintain a constant beacon. This is especially important in light that for an alien species to know to transmit something to earth directionally, they would need to be within a hundred or so light years to have detected our transmissions.

But if a species had not detected us directly, they may have known something interesting was going on here long ago when they noticed the amount of oxygen in our atmosphere. Oxygen is weird stuff, and highly reactive, so if it's in an atmosphere and being replenished, then it needs a source. Life is a very strong source. They might conclude that life is the most likely cause, and might take a chance and send a signal just in case someone intelligent was here. But they might not be willing to spend too much energy on it, just like us. After all, a planet full of dinosaurs is not going to respond. For all they know, intelligence might not have evolved here yet. But it still might be worth a shot to send a repeating signal towards a habitable planet with liquid water.

So how do you know when to look for the signal returning? To find a Benford beacon, you simply need to know the period at which it transmits. If the Wow! signal or TYC 1220-91-1 are Benford beacons, it has been suggested that we should check these targets with the thinking that the aliens may repeat the signal at intervals tied to pi or some other universal value coordinated along with some periodic object, such as a nearby pulsar or variable star. Or maybe some other basic periodic fundamental from science or mathematics to see if they've given us a clue as to when the signal will return.

So was the Wow! signal and others E.T.'s attempt at saying hello or mapping asteroids? Possibly. Will we ever know for sure? That unfortunately seems highly unlikely as far as the past signals are concerned due to lack of resources to watch them long-term. Personally, I think that if we find E.T. it will be in some unexpected way. Perhaps some astronomer studying stellar chemical composition will see something unnatural in a star's spectrum, such as plutonium, that points to alien influence on a star's composition. Or perhaps it will be in the spectrum of one of the exoplanets, maybe we will see their oxygen. In any case, whether we find out if we are truly alone or the universe is teeming with life, I hope it happens sooner rather than later. It's the one thing I'd really like to see before my time on this world comes to an end.