the "wow!" signal -- 1/23/19
Today's selection -- from Out There by Michael Wall, PhD. The Wow! signal, and why it is important to our search for extraterrestrial life:
"Two days after Elvis Presley died, astronomer Jerry Ehman was sitting at his kitchen table, poring over an eye-straining thicket of numbers and letters on computer printouts. ... Ehman had volunteered to look for interesting patterns in this messy mass of data, which had been collected by Ohio State University's Big Ear radio telescope.
"Something in the jumble caught Ehman's eye: the vertical string 6EQUJ5. It was so surprising that he circled the mini column with his red pen and wrote 'Wow!' in the margin in a lovely, looping script. ...
"6EQUJ5 was code describing a radio signal that had come in three days previously, on August 15, 1977. Ehman saw that the Wow! signal, as it has come to be known, was strong, covered a narrow range of wavelengths, and lasted 72 seconds, as would be expected from a deep-space source. (This was the length of time that the Big Ear could observe a distant cosmic target, before Earth's rotation rolled another patch of sky into view.) All of these characteristics were consistent with a transmission from an alien civilization.
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| The original printout with Ehman's handwritten exclamation is preserved by Ohio History Connection. |
"But there was more. The Wow! signal's frequency was 1,420 megahertz -- squarely within the 'water hole,' the slender, radio-quiet range that many astronomers had predicted ET would use to contact us. The name stems from its position between the frequencies of naturally occurring cosmic hydrogen atoms (H) and hydroxyl (OH) molecules, which together form water. Also, it's a kind of joke: the water hole should attract conversation, just like an office water cooler. (If you're a fan of nature shows, water hole may evoke images of wildebeest getting ambushed by lions or crocodiles at dwindling, muddy pools, which is a valid image as well, if ET means to do us harm.)
"This was very intriguing indeed, but astronomers would need more information before they could say anything definitive about the Wow! signal. For starters, they'd need to observe it again. So Ehman and his colleagues tried with the Big Ear, again and again. Nothing. Other astronomers sought to pick it up as well, using a variety of different scopes. Silence. Researchers have continued this effort over the decades, and nobody has had any luck. The Wow! signal was a one-off, a single cry in the dark.
"So what was it?
" 'I don't think it can ever be determined,' Ehman said.
" 'I'm frustrated that I can't draw any further conclusions than I already have.'"
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