Strong Signal, Possibly From Proxima Centauri, Detected at Parkes Observatory

Miscellaneous and Personal Stuff I Must Share
1

I haven’t seen another thread about this, so I thought I’d start one. The story is thus:

Breakthrough Listen, a SETI radio survey, was using the Parkes Radio Telescope to look at solar flares on Proxima Centauri, the closest star to us (just over 4 light years away). Buried in the data they found a narrowband signal at 982.002 MHz. It is being compared to the famous “Wow!” signal. The signal appears unmodulated, like a carrier wave. or perhaps the modulation is of a type or resolution we can’t see - at least after 4 light years of travel.

Original story from the Guardian here

The signal was present for four hours, during which the scope did a standard test for determining if a signal was coming from space or the ground - the telescope was moved slightly off-axis from the target and back again. If the signal doesn’t change, it is likely coming from the ground. But if the signal fades when the scope moves off-axis, it tends to corroborate that the signal is in fact coming from the direction of the target. In this case, the signal faded as a non-terrestrial signal would.

Apparently, this story was leaked from a scientist at Parkes as they prepare to release a paper on the signal. There’s no paper as of yet - just the hearsay from inside the group. But they sound awfully damned excited.

Some noteworthy things, both pro-and-con this being an alien signal, besides the fact that it’s never aliens:

Against: The signal is nearly right on 982 MHz, but there’s no reason for an alien civilization to use our numbering systems. An Earth second has no meaning to Proxima Centaurians, so there’s no reason to send a beam on 982 MHz rather than 982.384 MHz or any other number. Could be coincidence, though.

For: The signal persisted in the same region of sky for four hours. That eliminates all LEO satellites. Proxima Centauri is on a plane 60 degrees from the equator, which also rules out geostationary satellites. There are a handful of military satellites in elliptical 60 degree orbits, but only at apogee would they stay in the field of view that long. And as far as we know, they don’t use anything close to 982 MHz for communication. The odds that it’s one of them is… astronomical, I’d think.

For: The signal appears to be blue-shifted in a way consistent with a signal being transmitting from an orbiting body while it’s orbit takes it in our general direction. If Parkes could have listened to it longer, it might have red-shifted eventually. But the fact that it is Doppler shifted at all also is a strike against it being something on the ground.

Against: It’s never aliens. Until it is.

That’s about it. For now, it’s super-weird and unexplained. We don’t know of any natural phenomenon that generates that kind of narrowband signal, and all the tests for RFI and such have so far come up negative.

But until we see the paper, that’s about all we have to go on. Possibilities are still that it’s a satellite or a high altitude spy plane or something, or it’s not coming from Proxima Centauri but some place further along in a line behind it, or it’s some kind of equipment error or hoax, or some other unknown unknown like a newly discovered natural phenomenon that can make such radio signals. Or maybe a weather balloon, with a radio transmitter, or something like that. But so far, they haven’t found anything it could be that can match the characteristics of the signal I listed above .

For now, it’s an open mystery. Paper coming “in early 2021”.

Comments?

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Aliens. Totally aliens. I know. The aliens told me.

No, it sounds interesting.

3

A radio spectrum listing states that part of the spectrum is for aeronautical radio navigation (things like DME) and for the US Department of Defense’s JTIDS (datalinks system). JTIDS per its wiki though, employs spread spectrum among other things. I wouldn’t expect one single peak from it at only that frequency.

Awfully close, astronomically speaking. Proxima is a flare star system too, right? Not at all conducive for developing Earth-like complicated life. IOW, they’d be really alien.

Four hours of signal, during which Earth is moving ~30 km/s around the Sun. 14,400 sec * 30 km = at least a 430,000 km wide beam. Is that narrow or wide for a directed radio transmission traversing 4.3 light years? I.e., if it was a transmission, was it aimed only at Earth, or was it more of a “To Whom It May Concern?” I don’t think we’d want to reply.

Neat. Probably nothing, but we are seeing some weird stuff in the last few years. The Dyson shell possibility, one or two extrasolar visitors to the Solar System, now this.

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My money’s on “previously unknown type of flare behavior, possibly producing a natural maser effect”. Just because it came from another star doesn’t mean it’s aliens.

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I think that the biggest thing that will happen here is that the scientist that leaked this is going to have a hard time ever finding another team of researchers willing to work with them.

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Yeah, all the above possibilities are more likely than aliens. And even though there is a planet in Proxima’s ‘habitable zone’, the star gives off big tlares (which is why they were looking at it), and the planet prbits very close tontgd star and is likely tisally locked, which makes it a poor candidate for intelligent life.

Still… the signal was found more than a year ago, and the scientists who have talked have not indicated that they have any candidates for what it could be.

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Can we be sure no space agency on Earth has secretly launched a vehicle toward Centauri just for shits and giggles? Say, having lost the space race, someone in the Kremlin decided they wanted the first spacecraft to reach another star to have a hammer and sickle painted on the side, even if that took tens of thousands of years.

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I’m a little confused about the determination of the signal being blue/Doppler shifted. If the signal was only present for 4 hours, how did they determine it was shifted ? In order to determine a “shift”, wouldn’t you have to also observe either a non-shifted, or red shifted “same” signal ? Or was it based on a signal normally present from Proxima in the 980 Mhz area ?

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Maybe it’s lupus?

My non-existent money’s on “previously unknown natural phenomenon”.

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The irony of it is that the same observations that detected this signal were also part of the observations that concluded that Proxima b – a theoretically habitable planet orbiting that star – was so close that the excessive flaring from the dwarf star would have sterilized it and made it impossible for life as we know it to exist.

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Meanwhile, on Proxima Centauri’s Whatever Planet the scientists are going "huh - we’re getting signals from Sol 3? Isn’t that a single-star system, rather boring yellow sun? How does anything on the planet get enough energy to deeble its flarbs without a flare? And it rotates? How could intelligent life adapt to every changing light and dark in such a short time frame? This is a poor candidate for intelligent life. If there is life there it must be really alien!

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Cool!

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It was a dialtone. They got tired of waiting for us to put in a number.

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They are still bitching about the internet going down for hours because of that solar flare on Proxima Centauri VII.

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Here’s another article from Scientific American.

Very good question. From what I have read, the signal did shift in frequency over time. The ‘four hours’ of observation comes from multiple 30 minute observing windows over 30 hours. Proxima b has an orbital period of only 11 days, so if a signal was coming from there it definitely would have had a doppler shift that varied meadurably over 30 hours.

However, the astronomers say the shift was in the wrong direction from expected - they expected a red shift, but it blue shifted. I’m not sure how they can make that determination. Doppler shift of a signal from Proxima Cenauri would be caused by:

  • The rotation of the Earth.
  • Earth’s orbit around the sun.
  • The speed at which the Proxima Centauri system is moving in relation to Earth.
  • Whatever orbital/rotational velocities derive from the movement of the transmitter or the planet it is on.

The last one is hard to quantify, because we have no idea where the signal is coming from in the Proxima system - if it’s coming from there at all. I’m also not sure why they would expect a red shift, since Proxima Centauri has a radial velocity toward the Sun of 22.2 km/s. However, Earth’s orbital velocity is 29.78 km/s, So I guess if Earth in the part of its orbit that is moving directly away from Proxima you would expect a slight redshift.

Except… there are at least two planets there, and they have very different orbital velocities. Plus, one rotates and the other probably doesn’t. And the signal could be coming from somewhere else entirely - Parkes has a beam width of 1/60 of a degree, which is actually a large chunk of sky for this kind of observation.

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Thank you. The clarification of the “4 hours” helps a lot. I took it to mean observation of the signal for a continuous 4 hours (and then it went away). Multiple observations over 30 hours makes sense for them to observe the shift.

I, too, am curious how they had come up with a prediction for the shift (red vs blue).

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Heh, maybe it is a signal and once translate it will say,

“Please deposit twenty-five cents now, to complete your call”

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But, what is the exchange rate for Outer Centaurian currency?

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It’s probably denominated in Quatloos.

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This sounds weird. The flares aren’t solar if they’re on a star other than the Sun. And why would a SETI program be studying natural phenomena? It’s a remarkable coincidence that an organization that wanted to find signals from intelligent civilizations would find one while they were trying to do something else that’s not their mission.