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Space

Euclid Telescope Captures Einstein Ring Revealing Warping of Space (theguardian.com) 38

Europe's Euclid space telescope has captured a rare "Einstein ring," showing light from a distant galaxy bent into a perfect circle by the gravity of another galaxy sitting between Earth and the source, the European Space Agency said.

The phenomenon, spotted around galaxy NGC 6505 some 590 million light-years from Earth, reveals the warping of space predicted by Einstein's theory of relativity. The background galaxy, located 4.42 billion light-years away, appears as a complete ring of light around NGC 6505.

"An Einstein ring as perfect as this is extremely rare," said Open University astronomer Stephen Serjeant. Analysis shows NGC 6505 contains about 11% dark matter, a key focus of Euclid's mission to map the universe.

Euclid Telescope Captures Einstein Ring Revealing Warping of Space

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  • by blue trane ( 110704 ) on Monday February 10, 2025 @10:32AM (#65155691) Homepage Journal

    Why isn't the ring an ellipse?

    • Pure guesswork but I presume we see a roughly circular shape because the galaxy in front looks pretty circular, from our point of view.

      The four brighter spots probably reveal the shape of the galaxy behind it, to some degree. It looks like you can draw a straight line from bottom-left to top-right. Top-left and bottom-right are not prefectly aligned, but it looks like you can draw a V between them, whose angle is bisected by the straight line we drew previously. So perhaps the furthest galaxy is not perfect

      • by beelsebob ( 529313 ) on Monday February 10, 2025 @11:42AM (#65155983)

        Not the background one, the foreground one. The gravitational field of the foreground galaxy (and any other matter in between) is not perfectly even. For some parts of the ring, the strength of the bending is perfect to focus light onto our telescope, for other areas, itâ(TM)s either too strong or too weak, and focussed the light either between us and the nearer galaxy, or behind us. Either way, we get the light from the background galaxy all smeared out, and only capture a tiny fraction compared to the parts where itâ(TM)s well focussed.

    • by almitydave ( 2452422 ) on Monday February 10, 2025 @11:33AM (#65155941)

      Because as every nerd knows...

      There are four lights!!!

    • Because we're not perfectly along the line between the source(es) and the lens, so the light doesn't bend around in a complete circle, but just gets bent. It's nearly impossible to get a perfect ring, as that would require a perfect point source, spherical lens, and extremely lucky positioning. Instead, some spots of the source get bent but not smeared into a circle.
      • Four brighter spots on a ring though - that's odd. It implies that we're looking more or less down a four-fold axis of symmetry of the "lensing" field.

        Unless I'm misunderstanding the optics of the situation, and there's some quadrupole field producing the focussing. Which there is in the "crossed polars" where I did my optical mineralogy, but I don't see the analogue in this situation.

        Ho hum. So the immediate thing to do is to find the paper and read that, not a regurgitated press release.

    • by Tablizer ( 95088 )

      Why isn't the ring an ellipse?

      God deleted all the ellipses. Didn't match the drapes. Too bad for those sorry ovoids.

  • Smiley (Score:5, Interesting)

    by Quantum gravity ( 2576857 ) on Monday February 10, 2025 @11:19AM (#65155893)
    Here's another Einstein ring, which is amusing because it looks like the smiling Cheshire Cat.
    https://science.nasa.gov/missi... [nasa.gov]
    • by Tablizer ( 95088 )

      it looks like the smiling Cheshire Cat.

      That's where all of Schrodinger's unfortunate lab cats go.

      From there they spew revenge, giving us goofy AI, fake news apps, and comic-book-villain-like politicians.

  • by rickb928 ( 945187 ) on Monday February 10, 2025 @01:26PM (#65156373) Homepage Journal

    So if you work at it with enough gravity, you can fold space and boom FTL drive.
    Don't count on the spice. That way is trouble.

    • ... FTL drive.

      Because space 'disappears', one is not traveling faster than light. The cost of making space disappear, is getting sucked into the 'fold', oneself. We currently don't have an answer for that. Being able to switch gravity on and off, is one (theoretical) technology for crossing vast distances.

  • by Fly Swatter ( 30498 ) on Monday February 10, 2025 @02:39PM (#65156647) Homepage
    If you have a Slip-N-Slide in your lawn, and you placed it over a rock in the grass; The water going down the slide will flow around the rock. How is that warping space? The light is doing the same thing around the galaxy's gravitational forces.

    Neat effect to the viewer but I guess my dumb idea of warping space doesn't match theirs.
    • It’s more accurate to say that it is warping space-time, not just space. A black hole appreciably warps space-time, whereas a slip and slide on a rock warps it only by a negligible amount.
      • If there is a frog sitting downstream close to the rock, the effect isn't negligible from that frog's perspective.

        We are Frogs.
    • by Tablizer ( 95088 )

      Imagine the progress we'd have by now if Isaac Newton owned a Slip-N-Slide.

  • As I understand it, Einstein's contribution here was not so much predicting the existence of these rings as explaining their size.

    • Einstein's contribution here was not so much predicting the existence of these rings

      Well, yes, you could say that. People started speculating about the interaction between light and gravity in the mid-late 1700s. And Lorentz (of the contraction/ dilation/ Factor) and Michelson and Morley were looking for experimental evidence of that from a different theoretical basis in the late 1800s (1885 to 1897, IIRC, but I won't go to the gallows over the dates).

      as explaining their size.

      Einstein said, at several poin

  • How do they know? I thought this stuff was theoretical at best.

    • Dark Matter is unconfirmed and largely undefined, but the observations that made us create it are very real.

  • The cited Grauniad article is a re-hash of an ESA press release [esa.int]. The actual paper is published in Astronomy & Astrophysics. DOI: 10.1051/0004-6361/202453014 https://www.aanda.org/10.1051/... [aanda.org] as-printed PDF [aanda.org]. It's probably on Arxiv too, but the A&A article is Open Access, so "meh".

    The Grauniad article - and the ESA press release - both neglect to mention the scale of the two images presented. Fortunately the paper does (meaning I don't need to hack-about in SIMBAD to measure information about NGC 65 [unistra.fr]

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