Radiosignal Wow! from the space has natural origin - no aliens this time, sorry

Mistery of the "Wow!" signal, recorded by the radiotelescope"Big Ear" in the August, 1977, solved.  A team of researchers from the Center of Planetary Science (CPS) revealed that Wow! was emitted by the cloud of hydrogen, following the comet  266/P Christensen, that had not yet been discovered  back in 1977.

Image:  Big Ear Radio Observatory and North American AstroPhysical Observatory (NAAPO)

The signal was so strong that that team member Jerry Ehman scrawled "Wow!" next to the readout. For 40 years scientists could not explain the origin of this signal. It was popular candidtate for the first alien transmission obtained from the space. All possible natural sources - signals reflected from asteroid, stars, nebulae, or even Earth's noise, were ruled out. The signal was emitted at hydrogen frequency of 1420 MHz - various SETI projects search aliens at this frequency for almost 60 years. Numerous teams directed their radiotelescopes at the point in the sky, where signal was detected, but it has not been repeated.

Then in 2016 suggested that the signal might have come from a hydrogen cloud accompanying a comet - this explained why it was not seen again - comet is moving fast.

The team noted that two comets had been in the same part of the sky that the Big Ear was monitoring on that day. Those comets, P/2008 Y2(Gibbs) and 266/P Christensen had not yet been discovered. The team then tested their idea as the two comets appeared once again in the sky from November 2016 through February of 2017.

Image:   The Center for Planetary Science 

The team reports that radio signals from 266/P Christensen matched those from the Wow! signal 40 years ago. To verify their results, they tested readings from three other comets, as well, and found similar results.

Finally, the conclusion: it is impossible yet to confirm that Wow!  was generated by 266/P Christensen, while there is a big probability that it was created by a comet.

Unfortunately, there is no alien SOS signal or something like this time, but we will continue to look in the sky in search of intelligent life.

Source: http://planetary-science.org/wp-content/uploads/2017/06/Paris_WAS_103_02.pdf