If Aliens Beam Us a Signal, What Should We Expect?
by Elizabeth Rayne May 21, 2018 (syfy.com)
• If another intelligent species were trying to transmit a message to Earth, a weak radio signal from some distant galaxy might get lost in the chaos of light and noise from cell phones, wifi, TV and radio broadcasts, satellites, microwaves, traffic jams, and cities that never sleep, not to mention cosmic phenomena like black hole collisions and fast radio bursts.
• “By far the biggest challenge in radio SETI (Search for Extraterrestrial Intelligence) is what we call radio frequency interference,” said UC Berkeley SETI Research Center director Andrew Siemion. For example, the Wow! signal that was thought to be first contact for years (picked up by Ohio State University’s Big Ear radio telescope in 1977) was revealed to be the radio frequency emitted by the hydrogen gas from two comets.
• We are now able to search 10 billion radio channels as opposed to the hundreds that could be investigated when SETI investigations first started. How exactly would we be able to tell an extraterrestrial signal apart from all this visual and auditory pollution? Advances in astrophysics and technology have made it possible to search through more types of signals, analyze data faster, and determine which part of the electromagnetic spectrum we should be watching for a signal from another planet.
• Using such advanced technology, scientists have evaluated signals from a couple thousand star systems so far. And every one of these suspicious signals from outer space has been ruled out by some kind of interference. But SETI still has about a hundred billion stars to go.
Aliens could be trying to get through to us right now and we might not even know it. Even if another intelligent species was trying to transmit a message to Earth, a weak radio signal from some distant galaxy could get lost in the chaos of light and noise from cell phones, wifi, TV and radio broadcasts, satellites, microwaves, traffic jams and cities that never sleep.
That signal also has to contend with disruptive cosmic phenomena like black hole collisions and fast radio bursts being zapped through space before it reached a network of SETI (search for extraterrestrial intelligence) radio telescopes.
“By far the biggest challenge in radio SETI is what we call radio frequency interference,” UC Berkeley SETI Research Center director Andrew Siemion told Seeker. “Because we use our own technology as an example of what we should be looking for we in fact find many many examples of our own technology and those examples actually pollute the signal that we see especially with radio telescopes.”
How exactly would we be able to tell an extraterrestrial signal apart from all this visual and auditory pollution? The Wow! signal that was thought to be first contact for years was actually revealed to be the radio frequency emitted by the hydrogen gas from two comets. Hypersensitive instruments have been set off more than once by triggers that were much closer than scientists thought, including that one infamous case where the source of what was assumed to be a hello from aliens was actually no further than the visitor center of the observatory — a microwave oven without proper shielding had probably been heating up someone’s frozen pizza.
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Andrew Siemion, SETI (Search for Extraterrestrial Intelligence), Wow! signal
