Astronomers find no signs of alien tech after scanning over 10 million stars

CNET ^ | Sept. 7, 2020 8:36 p.m. PT | Jackson Ryan

[BenLurkin]

The study, published in Publications of the Astronomical Society of Australia on Monday, details a search for extraterrestrial intelligence (SETI) using the Murchison Widefield Array (MWA), a collection of 4096 antennas planted in the red soil of Western Australia that detects radio signals from space. "They are little spider-like antennas that sit on the ground," explains Chenoa Tremblay, co-author on the study and astrophysicist with CSIRO, an Australian government scientific research organization.

Tremblay and co-author Stephen Tingay, from the International Centre for Radio Astronomy Research, used the MWA to listen out for "technosignatures," or evidence of alien technology, in a portion of the sky around the Vela constellation. Tremblay explains this region is scientifically interesting because a large number of stars have exploded and died, creating ideal conditions for new stars to form. The search for extraterrestrial life "piggy-backs" on other work studying this region to understand the life cycle of stars.

But how can you tell a radio signal from space is coming from an alien civilization? "Think of a car alarm when you leave your lights on, where there are a series of equally spaced 'ping' sounds," Tremblay says. The survey looks for a repeating ping that may be escaping noise from a planet or "a purpose built signal."

After listening to the Vela region for 17 hours, no unknown signals were detected. While the survey was able to capture over 10.3 million stellar sources and contained six known exoplanets (likely many more exist in the region), the team notes it was like trying to find something in an ocean, but only studying "a volume of water equivalent to a large backyard swimming pool."

And there's another big caveat.

"Looking for technosignatures is assuming that the civilisation have technology similar to our own," says Tremblay.

[PJ-Comix]

According to Kilgore Trout, Space Aliens communicate by tap dancing and farting.

[SunkenCiv]

"But I am not really willing to accept your premise, because it may well be that the means of communications they have are of a kind that we do not know how to receive, and that they would not have the means of communicating with sufficiently powerful radio or optical signals. That is something which, technologically, is too difficult for them but they would have some other means we would not recognize." -- Thomas J. Gold, 'Communication with Extraterrestial Intelligence' (Sagan, ed)

"To consider the Earth as the only populated world in infinite space is as absurd as to assert that in an entire field of millet, only one grain will grow." -- Metrodorus, 4th c BC Greek philosopher

"Heaven and earth are large, yet in the whole of space they are but as a small grain of rice. How unreasonable it would be to suppose that, besides the heaven and earth which we can see, there are no other heavens and no other earths." -- Teng Mu, 13th c AD Chinese philosopher

[GreenLanternCorps]

[Svartalfiar]

As to radio waves - back to the 9 billion people, every little town around the world now has a radio or tv station, licensed or not, most broadcasting 24 hours. Not to mention ham radio broadcasts, podcasts and internet. Even remote areas of the world have satellite links. That’s a whole lot more white noise than existed in 1950, when tv stations went off the air at midnight, there was no internet and ham operators were few and far between. There’s a peak right behind me that we jokingly call an alien base it has so many microwave receivers/repeaters. And then there’s skylink, which will theoretically enable internet from any point on earth and will quadruple bandwidth use. And militaries around the world with their own dedicated bands. We are a lot noisier, and brighter now than ever before.

Are we though? Sure we're "noisier", but does that actually translate into actual noise in the galaxy? EMR power drops with the cube of the distance (if I remember correctly), so even the Aricebo signal is weaker than the galaxy's background radiation by now, and that has barely made it past part of our small arm of the Milky Way, much less the rest of the galaxy.

[sten]

even at a single light year away, what the hell would they expect to find?

unless they’re making MASSIVE ships, you won’t see them

a dyson sphere? ring world?

just seems over the top for what would be needed.

of course, maybe the evidence of their existence ... is us

[CardCarryingMember.VastRightWC]

Or a more pessimistic possibility:

• Radio waves only exist for a microscopically tiny window of time, because...
• Not many years after civilizations learn to use radio waves, they develop nuclear bombs, with the potential to wipe out all life on their planet (cockroaches excepted).
• Not long after they *think* they have the nuclear proliferation monster under control, they develop the internet.
• The internet's overall effect is to drive people apart, hating each other, going psycho.
• The combination of hundreds of millions of nut cases plus the nukes, obliterates the civilization and stops all the radio waves, about a century after they first started.