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posted by janrinok on Wednesday February 21, @11:42AM   Printer-friendly

SETI Institute Employs SETI Ellipsoid Technique:

In a paper published in the Astronomical Journal, a team of researchers from the SETI Institute, Berkeley SETI Research Center and the University of Washington reported an exciting development for the field of astrophysics and the search for extraterrestrial intelligence (SETI), using observations from the Transiting Exoplanet Survey Satellite (TESS) mission to monitor the SETI Ellipsoid, a method for identifying potential signals from advanced civilizations in the cosmos. The SETI Ellipsoid is a strategic approach for selecting potential technosignature candidates based on the hypothesis that extraterrestrial civilizations, upon observing significant galactic events such as supernova 1987A, might use these occurrences as a focal point to emit synchronized signals to announce their presence.

In this work, researchers show that the SETI Ellipsoid method can leverage continuous, wide-field sky surveys, significantly enhancing our ability to detect these potential signals. By compensating for the uncertainties in the estimated time-of-arrival of such signals using observations that span up to a year, the team implements the SETI Ellipsoid strategy in an innovative way using state-of-the-arc technology.

[...] In examining data from the TESS continuous viewing zone, covering 5% of all TESS data from the first three years of its mission, researchers utilized the advanced 3D location data from Gaia Early Data Release 3. This analysis identified 32 prime targets within the SETI Ellipsoid in the southern TESS continuous viewing zone, all with uncertainties refined to better than 0.5 light-years. While the initial examination of TESS light curves during the Ellipsoid crossing event revealed no anomalies, the groundwork laid by this initiative paves the way for expanding the search to other surveys, a broader array of targets, and exploring diverse potential signal types.

[...] The SETI Ellipsoid method, combined with Gaia's distance measurements, offers a robust and adaptable framework for future SETI searches. Researchers can retrospectively apply it to sift through archival data for potential signals, proactively select targets, and schedule future monitoring campaigns.

"As Dr. Jill Tarter often points out, SETI searches are like looking for a needle in a 9-D haystack," said co-author Dr. Sofia Sheikh. "Any technique that can help us prioritize where to look, such as the SETI Ellipsoid, could potentially give us a shortcut to the most promising parts of the haystack. This work is the first step in searching those newly-highlighted parts of parameter space, and is an exciting precedent for upcoming large survey projects like LSST."

Journal Reference:
Bárbara Cabrales et al 2024 AJ 167 101 DOI 10.3847/1538-3881/ad2064


Original Submission

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  • (Score: 5, Interesting) by Immerman on Wednesday February 21, @03:09PM (4 children)

    by Immerman (3985) on Wednesday February 21, @03:09PM (#1345497)

    By compensating for the uncertainties in the estimated time-of-arrival of such signals using observations that span up to a year

    So it sounds to me like they look for a significant event, and then for a year afterwards look for potential "reactions"?

    How is that supposed to work?

    Correct me if I'm wrong - but anyone within a light year of a supernova (so that they could conceivably "react" within a year as seen from our perspective) is pretty much dead unless they're VERY lucky and well prepared.

    I suppose it cold be a highly directional thing though, couldn't it? Say they're between us and the supernova, some time after they see the burst they transmit their own signal in the opposite direction (towards us), so that anyone further from the supernova in the same direction as them would see the supernova and then, when taking a closer look at the aftermath, see their signal. With hundreds of extragalactic supernovas per year you could cover most of the night sky in only, what, a few centuries maybe?

    It would only work for a very narrow cone radiating from the supernova, but by the same token their signal could be an similarly narrow tight beam transmission, and relatively weak since the supernova already attracted closer attention, so it would be relatively cheap compared to a more omnidirectional approach.

    Heck, we could do it ourselves just using our most powerful military radar beams, modulated to give them an obviously artificial origin. You don't necessarily have to say anything "We are here" is implied, and more complex communication could wait until they detected a "We see you" response.

    • (Score: 2) by bzipitidoo on Wednesday February 21, @09:25PM (3 children)

      by bzipitidoo (4388) on Wednesday February 21, @09:25PM (#1345540) Journal

      I don't understand this SETI Ellipsoid method, as the article doesn't say much about it. The picture shows a gigantic ellipsoid with, I presume, the supernova at one foci, and the Earth at the other. I gather that somehow this is a method of focusing so that we can better detect whatever signals are coming from the supernova. We could focus on anything, doesn't have to be a supernova.

      So, why focus on a supernova? Somehow all that energy can be utilized to amplify a signal. Of course intelligent beings can't be too close to it. I guess it can be so used from considerably farther than the closest safe distance.

      One thing to keep in mind about Supernova 1987A: it's 168,000 light years away. Meaning, that's how long ago it happened. If a supernova is used to search out intelligence capable of detecting such usage over such distances, and responding, that's a heck of a long time to wait for a response.

      • (Score: 3, Interesting) by Immerman on Thursday February 22, @02:45AM

        by Immerman (3985) on Thursday February 22, @02:45AM (#1345589)

        I don't think it can be used to amplify a signal - I'm pretty sure it's more a matter of it being an incredibly powerful natural beacon that will draw scrutiny so they could to try to catch our attention with a much, much weaker artificial signal.

        On further examination, it seems like ellipsoid bit is based on the idea that they send out a signal when they see a supernova, and when we see the supernova we can then use a 3-D starmap to determine when other stars saw it, and thus when the soonest "follow up signal" that could be sent from any other star would reach us. With those stars forming an ellipsoid shell that starts as nearly a line, and then grows as more time elapses: Basically, one year after we see the nova the shell will include all stars where the distance from nova->sender->us is one light-year longer than the straight nova->us path, after ten years it includes all stars where the crooked path is 10ly longer, etc.

        The ellipsoid comes as a result of the fact that all points where the crooked path is N units longer than the straight path will lie on the surface of the same ellipsoid. Basically the same reason you can draw a 2-D ellipse using two pins and a loop of string.

        It doesn't seem terribly useful though, since we don't listen to signals based on their 3D origin, but rather their 2D position in our skydome. And there will always be a bunch of stars near the surface of the ellipsoid in every direction.

        It also seems like a rather flawed idea, since since there's only a few supernovas per century in our galaxy, rendering them practically useless as a beacon. Who is going to have the equipment just sitting around to broadcast an incredibly powerful omnidirectional signal a few times a century, in response to an event that's incredibly difficult to predict?

        And if you include supernovas from other galaxies, then the ellipsoid becomes degenerate for senders in this galaxy, since the spherical supernova wavefront is effectively just a flat plane passing though our galaxy. While senders in other galaxies would be all but impossible to detect unless they were broadcasting with enough power to rival thousands of suns. Plus it would likely be fairly pointless to send such a signal, since any response would come at least many millions of years later, long after the original signal was probably forgotten.

      • (Score: 3, Informative) by hendrikboom on Thursday February 22, @03:11AM

        by hendrikboom (1125) Subscriber Badge on Thursday February 22, @03:11AM (#1345596) Homepage Journal

        Signals from the supernova might be intercepted and reacted to by civilisations on the ellipsoid. Those reactions would arrive here at roughly the same time. I suppose this might be analysed by looking in different directions and correlating the results.

      • (Score: 2) by sfm on Friday February 23, @07:52PM

        by sfm (675) on Friday February 23, @07:52PM (#1345941)

        I think the idea is to find a civilization that is on the path between Earth and
        the nova..... not necessarily in orbit around the remnants of the star.

        In this setup, we may be able to see a second signal coming from the same
        direction in space as the nova and infer it may be coming from an intelligent
        civilization.

  • (Score: 5, Touché) by takyon on Wednesday February 21, @03:51PM

    by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Wednesday February 21, @03:51PM (#1345500) Journal

    the hypothesis that extraterrestrial civilizations, upon observing significant galactic events such as supernova 1987A, might use these occurrences as a focal point to emit synchronized signals to announce their presence.

    That does not seem likely.

    SETI should pack it up and Yuri Milner should fund waves of spies to infiltrate the crash retrieval and reverse engineering programs.

    --
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  • (Score: 4, Interesting) by Barenflimski on Wednesday February 21, @05:13PM

    by Barenflimski (6836) on Wednesday February 21, @05:13PM (#1345509)

    If the ones that are signaling from the blown up star are the ones that blew it up, I'm not sure we want to be reaching out.

  • (Score: 5, Touché) by Mojibake Tengu on Wednesday February 21, @07:30PM

    by Mojibake Tengu (8598) on Wednesday February 21, @07:30PM (#1345525) Journal

    As those elites do not understand signals sent to them via established transfer channels and clearly worded by a couple of close neighborhood human civilizations, often sitting on the same continent, I don't think they could reach any success to grasp any exotic technology or meanings provided by true aliens distant civilizations from far Universe.

    --
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  • (Score: 2) by DadaDoofy on Wednesday February 21, @10:49PM (1 child)

    by DadaDoofy (23827) on Wednesday February 21, @10:49PM (#1345558)

    I was an early and enthusiastic participant in the seti@home project - one of the first. With the passage of time and perhaps some additional wisdom, I believe life forms even slightly more intelligent than us, would do everything in their power to keep their electromagnetic radiation from reaching beings with potentially ill intent.

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