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Space Communications

Strange, Repeating Radio Signal Near Center of Milky Way Has Scientists Stumped (livescience.com) 120

fahrbot-bot shares a report from Live Science: Astronomers have detected a strange, repeating radio signal near the center of the Milky Way, and it's unlike any other energy signature ever studied. According to a new paper accepted for publication in The Astrophysical Journal and posted on the preprint server arXiv, the energy source is extremely finicky, appearing bright in the radio spectrum for weeks at a time and then completely vanishing within a day. This behavior doesn't quite fit the profile of any known type of celestial body, the researchers wrote in their study, and thus may represent "a new class of objects being discovered through radio imaging."

The radio source -- known as ASKAP J173608.2321635 -- was detected with the Australian Square Kilometer Array Pathfinder (ASKAP) radio telescope, situated in the remote Australian outback. In an ASKAP survey taken between April 2019 and August 2020, the strange signal appeared 13 times, never lasting in the sky for more than a few weeks, the researchers wrote. This radio source is highly variable, appearing and disappearing with no predictable schedule, and doesn't seem to appear in any other radio telescope data prior to the ASKAP survey.

When the researchers tried to match the energy source with observations from other telescopes -- including the Chandra X-ray Observatory and the Neil Gehrels Swift Observatory, as well as the Visible and Infrared Survey Telescope for Astronomy in Chile, which can pick up near-infrared wavelengths -- the signal disappeared entirely. With no apparent emissions in any other part of the electromagnetic spectrum, ASKAP J173608.2-321635 is a radio ghost that seems to defy explanation. Prior surveys have detected low-mass stars that periodically flare up with radio energy, but those flaring stars typically have X-ray counterparts, the researchers wrote. That makes a stellar source unlikely here. Dead stars, like pulsars and magnetars (two types of ultradense, collapsed stars), are also unlikely explanations, the team wrote.
The report goes on to say that the closest match is a mysterious class of object known as a galactic center radio transient (GCRT), a rapidly glowing radio source that brightens and decays near the Milky Way's center, usually over the course of a few hours. "So far, only three GCRTs have been confirmed, and all of them appear and disappear much more quickly than this new ASKAP object does," reports Live Science. "However, the few known GCRTs do shine with a similar brightness as the mysterious signal, and their radio flare-ups are never accompanied by X-rays."
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Strange, Repeating Radio Signal Near Center of Milky Way Has Scientists Stumped

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  • by backslashdot ( 95548 ) on Thursday September 09, 2021 @02:04AM (#61778189)

    but it's not aliens. It's never aliens.

  • by mamba-mamba ( 445365 ) on Thursday September 09, 2021 @02:09AM (#61778195)

    OK, I guess that is three words. But its definitely time to build some planetary defense cannons.

    • by Tablizer ( 95088 )

      Seriously, I suspect something periodically burps gas or plasma that falls into a tight binary system of some kind that cooks the gas/plasma and emits repeating pumping hiccups as the binary objects orbit each other chewing on their lunch. (No, this is not cosmology porn, at least not intentionally.)

      • by jbengt ( 874751 ) on Thursday September 09, 2021 @07:57AM (#61778807)
        Yeah, but the mystery is, they haven't seen the signal in other parts of the spectrum like they would expect from your scenario.
    • I'm all for it, but my first question is, what are you going to use to shoot down a radio signal?

    • Are you aware that "Planetary Defense Cannons" are actually three words ?
      • Are you aware that "Planetary Defense Cannons" are actually three words ?

        Yep. But "planetarydefensecannons" isn't.

        • Are you aware that "Planetary Defense Cannons" are actually three words ?

          Yep. But "planetarydefensecannons" isn't.

          I own planetarydefensecannons.com It's for sale if anyone is interested.

      • OK, I guess that is three words.

        Are you aware that "Planetary Defense Cannons" are actually three words ?

        Are you aware that the subject lines of slashdot comments also have a comment body to go with them?

      • Are you aware that "Planetary Defense Cannons" are actually three words ?

        From Pirates of Penzance:
        "Allow me to explain in two words: We propose to marry your daughters."

        As in the musical, the explanation in two words is Planetary Defense Cannons.

    • Except those cannons will never be used on aliens and instead will always be used on humans.

      Imagine 'quelling' protests at the push of a button.

      "Sir, shouldn't the orbital defense cannon be pointing out into space and not at Earth?".

      "Shut up now or you will be scrubbing every latrine with a toothbrush for a month!"

    • Planetary Defense Cannons would most likely be a waste of time. If someone has the energy and tech to travel to our solar system, then they will most likely have the ability to bombard Earth (a predictably moving target) from outside the effective range of Earth's cannons. Imagine trying to hit a maneuvering target that is a few light minutes to a few light hours away from Earth. You would need some kind of FTL radar.

      Our only hope in such a case would be to decipher a 2nd alien transmission that gives us

      • Anyone who has the tech to make it to earth likely also has the tech to send hundreds of rocks from the asteroid belt directly at us. We currently have no way to stop the rocks or to reach the asteroid belt to stop them.

        I'm not sure we have the technology to build a "Planetary Defense Cannon" that could stop a single kilometer sized asteroid even if we had multiple years of notice.

        • Who needs asteroids? If you have the tech to accelerate it close to light speed, a pebble will suffice to blow up the Earth.

        • This is all just kidding around. But here is what I would say. If I were serious.

          "How about if we build the planetary defense cannons while you come up with a better plan. I will gladly switch my allegiance to your plan once you share it. And if it is better than planetary defense cannons."

          • This is all just kidding around. But here is what I would say. If I were serious.

            "How about if we build the planetary defense cannons while you come up with a better plan. I will gladly switch my allegiance to your plan once you share it. And if it is better than planetary defense cannons."

            Although a planetary defense cannon might be useful for a random rogue asteroid if the worry was actually interstellar aliens then it would make more sense to focus all our resources on technology that would allow us to be interstellar and both spread out and take the fight to them. Or if we can't be interstellar, maybe our weapon could be. An interstellar death star which could fire a giant gamma ray burst in their direction might do the trick....

      • then they will most likely have the ability to bombard Earth (a predictably moving target) from outside the effective range of Earth's cannons.

        Hey, I've seen that before [imdb.com].
  • Point source (Score:5, Interesting)

    by ClueHammer ( 6261830 ) on Thursday September 09, 2021 @02:31AM (#61778231)
    Any point source on a rotating sphere being received on another point receiver on a independent rotating sphere would also not align for very long... And who knows what other objects may pass between source and destination blocking the signal. Artificial or otherwise? There is not enough information to make a judgment call either way
  • It's obviously the microwave oven, kettle, toaster, iron or fridge. Don't quote me.
    • Just like the wow! Signal?
      • Well, the astronomers are Austrailian. So it would be a "mom" signal.
        ....
        Because "mom" is "wow" upside down.
      • No. The "leaky microwave" case was in the early 2000s, and appeared rather similarly to what we now know as "Fast Radio Bursts" (FRBs), while people were starting to spot FRBs and puzzling over what they were. So this weird factor of one particular observatory observing genuine (but rare) FRBs and these odd others, while other observatories observed the (rare) FRBs, but not the "leaky microwave" signal .. well it took a time to figure out what was going on, but after a couple of years, it was figured out, t
  • by backslashdot ( 95548 ) on Thursday September 09, 2021 @02:53AM (#61778275)

    I just hope this doesn't turn out like the time 20 years ago when Australian astrophysicists claimed they discovered a new intermittent signal they called "perytons" .. but it instead turned out to be a guy microwaving his burrito near the telescope antenna. I guess the clue was that the signal always showed up around lunch time. Reference: https://www.theguardian.com/sc... [theguardian.com]

  • It's noise coming from a failing power supply in the simulator we live in.
    • It's noise coming from a failing power supply in the simulator we live in.

      PSA - A failing switching power supply sounds kind of like eggs frying.

      The more you know..

      • Well, that's one popular failure mode for switched-mode power supplies. There are plenty of silent death modes too. And some more violent death modes : putting 750VAC down a mains lead that should only get 230VAC produces some nice loud bangs. Blew up the microwave too!
        • Well, that's one popular failure mode for switched-mode power supplies. There are plenty of silent death modes too. And some more violent death modes : putting 750VAC down a mains lead that should only get 230VAC produces some nice loud bangs. Blew up the microwave too!

          No doubt! We lost a neutral once in a transmitter site and one side of the building went low, and the other side went high. Lucky I was there, and managed to turn all the equipment off before it was all gone. Still lost some on the high side.

          • Yeah, that;'s not good. Taking power to our data acquisition units from generator sets which haul big motors - and sometimes get pushed by those same motors when the equipment backlashes - results in very dirty power sometimes. We burned out 4 power supplies for a non-PC system on a development job in the mid-90s - and I had to do an overnight dash the length of the country with the last remaining power supply, our last remaining AC voltage conditioners and surge suppressors, and left the Boss phoning local
            • Unfortunately, having our own power supply - and more particularly our own barrels of diesel next to an exploration oil well ... got vetoed, our power conditioners burned out, the data acquisition system burned out, and my colleagues held their heads in their hands. Until I got out a pencil and a note book and started doing the computer's job by hand.

              The development people learned a lot more from that debacle than I did. I just sent them a "told you so" card when the well finished a few weeks later.

              Have you ever used a saturating core power supply? Old School, heavy and clunky, not terribly efficient, but tough as nails. and can handle some pretty dirty power if need be. https://www.stichtinglogos.org... [stichtinglogos.org]

              We lost our last one, from the late 50's and haven't found any more. 80 pound supply was replaced by a switcher that weighed maybe a pound. Crazy good regulation. Fortunately it wasn't too expensive either, because I know it isn't as tough.

              • No, we didn't get a choice in the hardware - it was off the shelf stuff, but in some weird industrial rackmount configuration which the developer had worked on before - saving up development time, I guess. But with a total market of maybe three units, there wasn't a lot of point in trying to develop something new.

                But along came a change in tax laws, the bottom fell out of the industry, and we shelved developing our own all-encompassing system for lots of independent systems which we manually pulled the dat

  • Anybody checked for a loose wire on the back left antenna?

  • Whenever I build a new radio transmitter, it tends to do strange things too.
  • It's going to translate from alien to human as "We've been trying to reach you about your car's extended warranty..."
  • by bill_mcgonigle ( 4333 ) * on Thursday September 09, 2021 @06:02AM (#61778577) Homepage Journal

    Maybe someday we'll have a good map of all the galactic core black holes and be able to make predictions of relativistic orbits of various bodies ensnared in their gravity, but at this point it's an unsolvable large-scale relativistic many-body problem that /ought/ to look random.

    • Re:Black Holes (Score:5, Insightful)

      by burtosis ( 1124179 ) on Thursday September 09, 2021 @07:57AM (#61778805)
      There is no closed form solution, and never will be true. However that does not mean that it’s not solvable today through numerical approximations. The problem with long term predictions isn’t a lack of understanding how gravity or relativity works, it’s that extremely small deviations within measurement error produce wildly different outcomes long term. That’s not something that’s ever going away, it’s a feature of reality.
    • Umm, I think you'll find that work was published back in the 1990s (IIRC - I remember reading the paper, so after 1997, I think.)

      None of the stars in the SgrA* cluster are travelling anywhere near relativistic velocities. A few thousands of km/s at most. You're probably conflating SgrA* with inspiralling "compact objects" and their gravity wave signal, which does get very relativistic for a second or so. But that is most definitely not what is happening in the SgrA* cluster.

  • it's obviously Radio San Mar Sol.

  • by Vandil X ( 636030 ) on Thursday September 09, 2021 @08:39AM (#61778933)
    BE QUIET!. THEY'LL HEAR YOU!
  • Pining home.

  • There, I solved it for you. Send my Nobel and cool million along if you please.

  • "Pump up the volume, pump up the volume"

  • A rotating object, and since it's close to our galaxy's black hole, thousands of other stars (and dark objects, like brown dwarfs) block the signal as they orbit between us and it.

    • Sorry - people estimated the statistics on that back in the 1970s, got funding to look for such occultations and near-occultations, and ran the project from the late 1980s to - well, it is continuing in various forms. See the MACHO project [wikipedia.org] for references.

      It is a reasonable theory, denied by observations.

      • No, in the 1970s existence of a black hole at galactic center was speculation, only studies of certain types of stars' movement from mid 1990s and later in IR seem to indicate there likely is supermassive hole there, but to claim we know even all the stellar objects there or understand what interactions go on between them and the types of radiation to expect is nonsense even now.

        • I wasn't talking about the black hole theories. I was responding to by whitroth's ideas about

          thousands of other stars (and dark objects, like brown dwarfs) block the signal as they orbit between us and it.

          Regardless of what the signal source is, the probability of it being occulted by intervening objects (or being subject to gravitational lensing focussing and defocussing it, as the intervening object moves across the field of view) follows similar statistics on the population of these objects, their masse

  • Not a 'come help me' one.

  • Very productive story.

  • Pak fleet escaping the core supernova chain reaction.
  • It is always advisable to Read The Friendly Paper, when you get the chance. When the "popsci" site describes it's journalist (on a "hard science" story) as : holds a bachelor's degree in creative writing from [somewhere], with minors in journalism and media arts., one's misgivings are likely to be well founded.

    Firstly, the paper [arxiv.org] without any adverts, tracking scripts or any of that jazz. Just the data.

    The Friendly Summary seems concerned that this new discovery isn't terribly similar to previously identifi

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