# WOW! signal calculation of point source intensity

The WOW! signal's measurement took the average signal strength over 12-second intervals. The average intensity's peak was just over 30-1 signal to noise, meaning that the 12 second interval had an average strength of 30-1. But evidence suggests the signal came from a point source. Has anyone ever done the math to estimate the point source strength? Is this even possible?

• Because the "big ear" was fixed, a point source is pretty straight forward, at least within a range of a certain number of arc minutes. One of the drawbacks to the big ear was that they couldn't point it. It just swept around with the rotation of the Earth. As I recall, scientists awaited eagerly for the next day when it would sweep past that point in the sky again but the next day, and every next day after, there were no more wows. A decade or so later they added the ability to turn the big ear and point it at stuff, in case another wow ever happened, but no such luck. – userLTK May 9 '18 at 0:46
• Understood. But the question is whether the actual point source signal-to-noise strength can be estimated from the data, or whether the intensity of the point-source signal can be estimated using the data – Dilettanter May 9 '18 at 0:48
• World Of Warcraft? I'm being absurd to demonstrate a point: always define your abbreviations, please. – Carl Witthoft May 9 '18 at 15:46
• @CarlWitthoft You're right, someone visiting the astronomy site may not know what the WOW! signal is. – Dilettanter May 9 '18 at 15:49

## 1 Answer

The plot is pretty straight forward. 6EQUJ5 puts the peak signal between Q and U, closer to U. The letters represent two digit numbers, 1-9, then A-Z. A being 10, Z being 35. U was the highest signal strength received equivalent to a 30.

Wikipedia has a nice summary of the event. The location is discussed here with some margin for error due to there being two listening devices and the design being, as I understand it, somewhat less than ideal.

While the signal remains unexplained, it was some 30 times stronger than baseline, but 3s and 4s were fairly common. It was only 7-10 times stronger than signal strengths they received regularly. I lean towards it being a natural but unexpected event, but there's not sufficient data to close the case, so to speak.

• This is helpful, but assuming a point-source, would not the actual peak be much higher than the peak of the graph because the graph is an average? – Dilettanter May 9 '18 at 1:10
• @Dilettanter I'm not an expert, but I don't think so. The article says there was a 72 second receiving window for a point source. It should start out at 0 or baseline, and end at 0 or baseline, but at 18 and 54 seconds - sin of 45 degrees maybe - about 71%. I don't know precisely how fast it should drop off in that 72 second window, but much higher - I don't think so. I think it would be like a single period (half period?) in a sine wave. It's not possible or practical to focus a receiver to infinity. It always captures a range or region and the point source moves through that region. – userLTK May 9 '18 at 1:40
• I see what you're saying. Perhaps this comes down to how much of the sky is in the big ear's listening path. My point is that the big ear took samples every 12 seconds. Perhaps in between measurements the signal strength was much higher -- how much higher is the question. I'm wondering because estimating the peak signal strength could give insight into whether the signal originated on Earth. For example, there would have to be some wattage range associated with the signal if we make an assumption about how far away this possible object of reflection was. Just wondering - maybe I'm off base – Dilettanter May 9 '18 at 4:23