Mysteerisignaali!Most curiously,
it occupies a very narrow band of the radio spectrum: 982 megahertz, specifically, which is a region typically bereft of transmissions from human-made satellites and spacecraft.
“We don’t know of any natural way to compress electromagnetic energy into a single bin in frequency” such as this one, Siemion says.
Perhaps, he says, some as-yet-unknown exotic quirk of plasma physics could be a natural explanation for the tantalizingly concentrated radio waves. But
“for the moment, the only source that we know of is technological.”
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Revisiting the data from 2019, Sheikh and her colleagues noted that the telescope had looked at Proxima multiple times in scans lasting 30 minutes over the course of a week. Breakthrough Listen uses a technique called “nodding,” where the telescope will spend a period of time looking at a target and then an equivalent period looking elsewhere in the sky,
to check that any potential signal is truly coming from the target and not, say, someone microwaving their lunch in an observatory’s cafeteria. “In five of the 30-minute observations over about three hours we see this thing come back,” Sheikh says, a hint that the signal indeed originated from Proxima Centauri—or some other deep-space source in that part of the sky—before making its way to Earth.
