Through The Wormhole: Are We Alone?Aliens almost certainly do exist. So why haven't we yet met E.T.? It turns out we're only just developing instruments powerful enough to scan for them, and science sophisticated enough to know where to look. As a result, race is on to find the first intelligent aliens.

But what would they look like, and how would they interact with us if we met? The answers may come to us sooner than we imagine, for one leading astronomer believes she may already have heard a hint of their first efforts to communicate.

Of all the signals received in the search for intelligent extraterrestrials, the Wow! signal is one that many people remember. And Jerry Ehman was the man who wrote it. Ehman taught astronomy and electrical engineering at Ohio State University and worked on early projects for Big Ear, a radio telescope at the university.

These telescopes collect radio waves from space. Because cosmic radio waves are weak, the telescope collecting dishes have to be large, more than three football fields long in Big Ear's case.

Ohio State let Ehman go after cutting Big Ear’s funding. Undeterred, he came back to Big Ear as a volunteer. Two colleagues helped Ehman. Without John Kraus, who conceived of the telescope, Big Ear wouldn’t have been listening.

Robert Dixon, Kraus’s former student, designed Big Ear's search plan, choosing the radio wavelength to listen to, and he corrected the listening to account for our galaxy’s spin. Without Dixon’s correction, Big Ear would have listened to the wrong wavelength.

This is the sixth episode. See the list of all episodes here: Through The Wormhole.

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