On August 15, 1977, an American astronomer, Jerry Ehman, recorded a "message" sent from space. The signal was picked up by the Big Ear radio telescope at the University of Ohio. Report took only 72 seconds, and Ehman named it WOW.

The event caused a great stir, and many trusted astronomers were of the opinion that it was a message from one of the cosmic worlds. The signal came from the M55 star cluster in the constellation Sagittarius.

Later, however, many scientists have heard that the emission of hydrogen (and judging by the wavelength, it was hydrogen) could come from a planet or satellite orbiting the Earth, an asteroid, a comet, etc.

This hypothesis became even more widespread in 2005, when astronomers discovered two comets - 266P / Christensen and P / 2008 Y2 (Gibbs). It was this pair of cosmic bodies that passed through the Sagittarius constellation in 1977, from July 27 to August 15, and their hydrogen clouds, which were several million kilometers long, probably became a source of radiation.

The results of this research were published in the Journal of the Washington Academy of Sciences.

Opinions of leading scientists on this issue differ. How is the thing with the famous WOW, it will be possible to check in 2017 - 2018 years, when both comets will cross again in the same places.

Sueneé: And why is the signal called WOW? This corresponds to the exclamation in English: "waaau", which Ehman marked on the printed record… :)