The ‘Wow!’ space signal was heard 40 years ago... Is the mystery now solved?

On this day 40 years ago, a mysterious signal was heard from space.

In August 1977, a team of astronomers studying radio transmissions from an observatory in Ohio recorded an unusual 72-second signal.

“It was so strong that team member Jerry Ehman scrawled "Wow!" next to the readout,” reports Phys.org.

Ever since then, scientists have been attempting to figure out the cause of the signal.

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“Possible sources such as asteroids, exo-planets, stars and even signals from Earth have all been ruled out. Some outside the science community even suggested that it was proof of aliens. It was noted that the frequency was transmitted at 1,420 MHz, though, which happens to be the same frequency as hydrogen,” the science site explains.

A handout image captured October 23, 2014, from a distance of about 7.8 km (4.8 miles) from the surface, of the comet 67P/Churyumov-Gerasimenko, made available by the European Space Agency (ESA) on Nov. 11, 2014. (Reuters)

More recently, researchers with the Center of Planetary Science (CPS) believe they have finally solved the mystery.

It was a comet that that was unknown at the time of the signal discovery, wrote lead researcher Antonio Paris last June.

“Those comets, P/2008 Y2(Gibbs) and 266/P Christensen had not yet been discovered. The team then got a chance to test their idea as the two comets appeared once again in the night sky from November 2016 through February of 2017,” reports Phys.org.

“The CPS suggested that the signal might have come from a hydrogen cloud accompanying a comet—additionally, the movement of the comet would explain why the signal was not seen again.”