WOW! SOURCE?
Most signals from space suspected to be of alien origin have turned out to have a natural source, but one signal has refused to go away. This is what is known as the “Wow!” signal, picked up by the Ohio State University’s Big Ear telescope on the night of 15 August 1977 during a search for extraterrestrial intelligence (SETI) session. It was a brief blast of radio signal so powerful that Jerry Ehman, the astronomer who spotted it on the data printout, ringed it and wrote “Wow!” beside it (see David Hambling, “Is there anybody out there?”, ). The signal was in the electromagnetic frequency band of 1420.4056 MHz, which is produced by the element hydrogen, and Ehman said “Since hydrogen is the most abundant element in the Universe, there is good logic in guessing that an intelligent civilisation within our Milky Way galaxyscanning the same area of the sky. Now, though, we do have a potential source for the signal. Astronomer Alberto Caballero has searched through a catalogue of stars from the European Space Agency’s Gaia satellite to see if there were any candidates. “I found specifically one Sun-like star,” he said. This was an object designated 2MASS 19281982-2640123, about 1,800 light-years away, that has a temperature, diameter and luminosity almost identical to our Sun. While no planets have so far been detected in the vicinity of this star, it is of a type that could have Earth-like worlds orbiting it, hospitable to a civilisation similar to our own that might have decided to send out a signal. As for the one-off nature of the signal, Caballero points out that whenever humans have attempted to communicate with other potential civilisations, we, too, have sent out single broadcasts, not repeating ones, such as the message sent toward the globular star cluster M13 in 1974 from the Arecibo radio telescope.
