# the "Wow" signal

What’s the dope on the detection of this signal?

I recently watched a “Naked science” episode on NatGeoTV which one of the SETI scientists theorized that it could have been a communication signal between two alien ships. From reading the wikipedia entry, the idea that it could have been from a natural source is debatable. Anyone have any info on this?

There’s really not a lot of data here. You have this anomaly that came in once. Listening to the same part of the sky didnt produce anymore signals. Also the fact that its on a specific frequency that is calculated using a 10 base system and a 60 second system proves to me that its terrestrial:

I dont see how someone arguing for ET could possibly explain that it came in exactly at 14.2700000.

This is why I think SETI is a waste of money. They are trying to find signals that we would use on earth. Don’t radio waves become static after a few lightyears or so? It also assuming aliens use a base 10 system. Isn’t base 8 “better” when compared to base 10?

The article you linked to doesn’t say the Wow signal was exactly 14.2700000 MHz. It’s talking about ways to determine if a “Wow”-type signal is terrestrial interference or not.

It’s a hypothetical, not what actually happened.

I have no idea what you mean about radio waves becoming static, and I’ve never heard of any SETI project that assumed that aliens use base 10 (or any other particular base).

I don’t know anything about signaling, so can someone explain why 14.27 is an exact number in decimal? What if it was 14.29 or 14.255, would that be evidence of human agency?

The number quoted was 14.2700000 MHz, not 14.27.

14.2700000 MHz means exactly 14270000 Hz, plus or minus 0.5 Hz, while 14.27 MHz, with no other qualifier, is typically assumed to be an approximate value that could lie anywhere between 14265000 and 14275000 Hz. If I found a source emitting at such an exact multiple of 10 kHz, I’m going to assume a human transmitter until proven otherwise.

It’s not the decimal that’s important for this argument so much as the long line of zeroes afterwards. If we measure the frequency of a signal to end with several zeroes (within the limits of our precision), then it’s likely that the time unit involved is some simple fraction or multiple of the second. A true alien signal would come in on a frequency more like 14.2763425206 GHz (plus or minus 0.0000000002 GHz) rather than 14.2700000000 GHz (plus or minus 0.0000000002 GHz).

Some simple wiki’ing gives this: Wow! Signal

Neither of these values is 14.2700000 MHz, so that’s not right. But doesn’t the fact that they’re near the hydrogen line suggest that they didn’t originate from too far away? I’ve heard of multiples of this frequency being suggested for our own attempts at contacting hypothetical extraterrestrials, because they would be relatively conspicuous and therefore easy for an observer to find. But this frequency itself would be quickly interfered with by interstellar hydrogen, wouldn’t it? IANAAstrophysicist, of course.

The other reason you wouldn’t want to use the hydrogen hyperfine line itself for a communication is because then your recipient would have to worry about the possibility that it was natural. It’s not too hard to come up with a scenario of something in nature that would emit a big burst right at that frequency; it’s harder to come up with a scenario that would emit at exactly twice that, or pi times that, or whatever.

I’m sure that many of you Dopers have heard of the Wow! signal (for those who haven’t; some people think that it may have been our first message from ET). I know that the signal was sent from an unoccupied area of space, on a radio frequency which I believe cannot come from natural sources. What I don’t get is, what exactly was in the signal? Was it significant simply because the signal came at all?

FYI, here’s a previous thread on the same subject.

Not static as opposed to dynamic, but static in the broadcast-signal sense. The signal-to-noise ratio deteriorates (or is presumed to deteriorate) below intelligibility.

Cheers for the link, Dewey. I did read through it but must admit, I’m still not sure I get it. Is the fact that it came through on a particular frequency the reason it could be a big deal? Obviously it’s not a direct message saying “Is anyone else out there?”, but wouldn’t you expect some kind of observable information with any such broadcast?

The signal is significant because it is a very narrow band of energy, which makes it much less likely to be of natural origin. It’s also on a protected frequency, which people aren’t supposed to broadcast on.

Unfortunately, there just isn’t that much you can say about the WOW signal one way or another, because there just isn’t much data there. The antenna that picked it up as actually a double antenna that does not move relative to the earth, so it scans the sky based on the earth’s rotation. The way it is designed, you can’t tell if a signal is coming in one antenna horn or the other. What you would expect, if it picked up a constant signal, is that you would see the signal twice, once for 72 seconds (peaking about halfway through) as the first antenna horn swept past, then again three minutes later for another 72 seconds as it gets picked up by the second antenna horn. The WOW signal only got picked up once, though. Of course, the signal could have started or stopped in between the sweep of the two antenna horns, so that doesn’t necessarily say much.

And that’s it. That’s about all we know. Yes, it was a signal. Was it extraterrestrial? Who knows. If both horns had picked up the signal, this would have been better evidence that it was extraterrestrial, but being picked up by only one horn doesn’t necessarily mean that the signal was not extraterrestrial.

The signal is significant because it was strong relative to the background noise. There isn’t enough data to make any other conclusions about it. This isn’t like some sci-fi movie where the entire signal was captured and can be analyzed with some spiffy 3-D screen display resulting from it. All we have is a chart of signal strength. We know the frequency. We know the signal strength. We know the bandwidth (roughly) of the signal. We don’t know how long the signal lasted, all we know is how long one horn of the antenna picked it up. That’s all we got. It ain’t much to work with. There may have been all kinds of “observable information” in the broadcast, but we don’t have that data.

Dr. Jerry R. Ehman, who discovered the signal, has cautioned against “drawing vast conclusions from half-vast data.” I personally like that quote.

Hmm. Sounds like we’d better call the world’s radio astronomers and explain to them that their field can’t exist.