There’s no such thing as a “close call” in SETI – either the radio telescope has picked up an alien signal, or it hasn’t. “Close” doesn’t exist in this one-bit experiment, any more than it does in pregnancy.

By Seth Shostak www.seti.org 6-13-17

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... At close to midnight on August 15, 1977, the massive radio telescope of the Ohio State University, known to its friends as the Big Ear, recorded a signal so impressive to the astronomer examining the instrument’s logs, he wrote “Wow!” on the computer printout.

It had all the characteristics one would anticipate from a signal produced by a deep space transmitter. This agreement with hopeful expectation, coupled with the undoubted appeal of the signal’s beguiling moniker, led to many efforts to find the WOW signal a second time. These attempts were made on such radio telescopes as the Very Large Array in New Mexico and, of course, the Big Ear itself. However, the result was always the same: radio silence.

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But a paper published more than a year ago by Antonio Paris and Evan Davies makes a different claim: a natural solution to the puzzle of the WOW signal. It wasn’t earthly interference, problems with the equipment, or even ET; it was natural radio emission from hydrogen gas streaming off a nearby comet. ...

The comet hypothesis, in my opinion, doesn’t work....
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An astronomer thinks he's pinpointed the source of a mysterious radio signal from space: a passing comet that nobody knew about. But his colleagues said they're still skeptical of the explanation, noting that comets don't emit radio waves in the right way.

By Jesse Emspak Space.com 6-13-17

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Yet several astronomers, including Ehman, think Paris is wrong about the comet....

"We should have seen the source come through twice in about 3 minutes: one response lasting 72 seconds and a second response for 72 seconds following within about a minute and a half," Ehman told Live Science. "We didn't see the second one."

The only way that can happen, he said, is if the signal was cut off abruptly. A comet wouldn't produce that kind of signal, because the gases that surround them cover large, diffuse areas. Nor would the comet have escaped from the radio telescope's field of view that fast.
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