Astronomers confirm that comet caused Wow! signal, not aliens

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Astronomers have confirmed that the Wow! signal, thought to be the most promising detection by SETI of alien life, was actually caused by a comet.

Last year, a group of researchers from the Center of Planetary Science proposed a new hypothesis that argued a comet might be the culprit. The frequency could be caused by the hydrogen cloud they carry, and the fact that they move accounts for why it seemingly disappeared. Two comets, named 266/P Christensen and P/2008 Y2 (Gibbs), happened to be transiting through that region of space when the Wow! signal was detected, but they weren’t discovered until after 2006.

To test the hypothesis, the team made 200 radio spectrum observations between November 2016 and February 2017. Sure enough, 266/P Christensen was found to emit radio waves at a frequency of 1,420 MHz, and to double check, the researchers moved their radio telescope by one degree. As expected, the signal vanished, and only returned when the telescope was trained back on the comet.

This story demonstrates once again why, in science, it is very dangerous to jump to any conclusions. The data we receive is a mystery. We must keep an open mind to solve that mystery.



  • Joe

    Sort of like the sonic boom that accompanies a very high performance aircraft as it travels.

  • LocalFluff

    It was a big surprise a few years ago when Chandra (I think it was) by accident measured x-rays from comets that happened to pass by its field of view. How could a comet emit high energy x-rays? Turns out the Solar wind interacts with the thin coma to generate even x-rays. It was in the models but it just hadn’t been dug out until the question was asked.

  • Mike Murphy

    Please see a rebuttal to this theory at, the link is noted in the center of the main page.

  • pzatchok

    I say the aliens are hiding behind the comet. Maybe even using it as their ship or base.

  • LocalFluff

    A few talks on comets have just been posted by Caltech. For anyone who wants to know more than necessary about it. Some quite clever reasoning. They make the most out of the little data available. Still mysterious.

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