back to article Grav wave boffins are unsure if they just spotted the smallest black hole or the biggest neutron star seen yet

Astronomers have detected what could be either the tiniest black hole or the largest neutron star found to date. Gravitational waves are emitted when two massive objects collide and merge with one another. The energy of the impact event ripples through spacetime, and these signals are detected by measuring the movement of …

  1. lglethal Silver badge
    Trollface

    So too small for a black hole and too big for a neutron star

    I propose a new class of objects falling between 2 and 5 solar masses that shall be called Neutron Holes! Wait... No, lets name them Black Stars, much cooler sounding.

    And look we just spotted one! My proposal is validated! Where do i collect my Nobel prize?

    1. Julz Silver badge

      Re: So too small for a black hole and too big for a neutron star

      A quark star?

      Not the cheese :)

      1. Vometia Munro

        Re: So too small for a black hole and too big for a neutron star

        Dark Star. The sudden disappearance of the world's entire supply of toilet roll confirms their existence.

    2. Annihilator Silver badge
      Pint

      Re: So too small for a black hole and too big for a neutron star

      "Black Stars, much cooler sounding"

      David Bowie - always ahead of the game even in death.

    3. Brewster's Angle Grinder Silver badge

      Re: So too small for a black hole and too big for a neutron star

      You need to type up a few equations first.

    4. Ugotta B. Kiddingme

      Re: "let's call them Black Stars"

      prior art

      The USS Enterprise is thrown back in time to Earth during the 1960s by the effects of a high-gravity "black star". Enterprise ends up in Earth's upper atmosphere, and is picked up as a UFO on military radar.

      1. Marketing Hack Silver badge
        Go

        Re: "let's call them Black Stars"

        And if Star Trek doesn't qualify, then the Simpsons' incredible streak of successful prognostication continues

        https://www.youtube.com/watch?v=afD7nMmdUpY

        1. Eclectic Man Bronze badge

          Re: "let's call them Black Stars"

          But what about the sci-fi film 'Dark Star'? doesn't that count?

          1. Rich 11 Silver badge

            Re: "let's call them Black Stars"

            'Dark Star' always counts.

            "Let there be light."

        2. Michael Hoffmann
          Unhappy

          Re: "let's call them Black Stars"

          Nobody mentions the Minbari ship "Black Star" from Babylon 5.

    5. Anonymous Coward
      Alien

      Re: So too small for a black hole and too big for a neutron star

      "Black Star" might actually be a name given in sci-fi/pop culture for these things.

      As for their real name, it already exists as either a predicted strange star or a quark star.

  2. Anonymous Coward
    Anonymous Coward

    "We don't know if this object is the heaviest known neutron star, or the lightest known black hole, but either way it breaks a record"

    I guess it ultimately doesn't matter now it's collided with a black hole... it's an ex-neutron star/dwarf black hole now.

    1. Anonymous Coward
      Anonymous Coward

      it's an ex-thing now...

      In which case, perhaps a "blue hole"?

      .

      For avoidance of doubt, we could prepend the name of an appropriately chosen Scandinavian country as well.

  3. KittenHuffer Silver badge

    I feel an overwhelming urge to quote Holly!

    Well, the thing about a black hole - its main distinguishing feature - is it's black. And the thing about space, the colour of space, your basic space colour, is black. So how are you supposed to see them?

    1. Forget It
      Headmaster

      Re: I feel an overwhelming urge to quote Holly!

      > So how are you supposed to see them?

      https://en.wikipedia.org/wiki/Hawking_radiation

      1. Andy Non Silver badge

        Re: I feel an overwhelming urge to quote Holly!

        Hawking radiation is very feeble and has yet to be detected in practice. Most of the radiation from a black hole is from the extremely hot accelerated matter that is being pulled into it and swirled around it in ever decreasing circles - before disappearing over the event horizon. There are also the colossal magnetic poles around black holes that also cause matter to give off lots of light, x-rays etc as charged particles swirl through the field.

        1. Anonymous Coward
          Anonymous Coward

          Re: I feel an overwhelming urge to quote Holly!

          Or here, the thing that escapes the black hole, gravity. Which propagates at the speed of light, and yet somehow escape the event horizon even as light does not.

          1. Tom 7 Silver badge

            Re: I feel an overwhelming urge to quote Holly!

            Not quite. The mass of the black hole bends space time so that its vertical on the time axis at the event horizon.

          2. Rich 11 Silver badge

            Re: I feel an overwhelming urge to quote Holly!

            and yet somehow escape the event horizon even as light does not

            Gravity is the warping of space-time, not something which behaves as a photon acting within space-time.

            1. Anonymous Coward
              Anonymous Coward

              Re: I feel an overwhelming urge to quote Holly!

              Yeah, gravity does not "escape" the black hole any more than the road escapes the car passing over it.

          3. tfb Silver badge
            Boffin

            Re: I feel an overwhelming urge to quote Holly!

            Gravity doesn't 'escape' the black hole: it's already present around it in the form of the deformation of spacetime.

        2. Vometia Munro

          Re: I feel an overwhelming urge to quote Holly!

          "Hawking radiation"

          a.k.a. grit.

        3. Anonymous Coward
          Anonymous Coward

          Re: I feel an overwhelming urge to quote Holly!

          Also, for Hawkins radiation to even work, requires certain temperatures around the black hole, and most if not all SMBHs are already too large to start evaporating unless the background radiation gets cooler (or some other mechanism allows it to be cooler near them?).

      2. tfb Silver badge
        Boffin

        Re: I feel an overwhelming urge to quote Holly!

        For a black hole to emit more Hawking radiation than it absorbs from the CMB it would have to have a mass equal or less than the Moon (approximately). No stellar mass or higher black hole would be detectable by Hawking radiation, even in theory.

        1. Claptrap314 Silver badge

          Re: I feel an overwhelming urge to quote Holly!

          Today. As the universe expands & cools, those numbers change.

    2. Toni the terrible

      Re: I feel an overwhelming urge to quote Holly!

      Didn't NASA say that space was really Taupe?

  4. Helstrom

    The Rebel Alliance tricked the Death Star III ("That's no Neutron Star - that's a space station") into getting eaten by a black hole thereby actually killing The Emperor for real this time.

    QED

    1. Anonymous Coward
      Anonymous Coward

      Unless The Emperor was smart enough to leave horcruxes well outside of the black hole.

  5. DS999

    Can't neutron stars grow bigger from accretion?

    It could steal mass from a companion though that's probably not going to add enough material to matter much. They could merge with a white dwarf or another neutron star if a companion had a slowly decaying orbit. The fact neutron stars larger than 2 solar masses or so are hard to find is probably because this sort of thing is comparatively rare - and if they become too big as result of this they'll collapse into a black hole so like goldilocks it has to be "just right".

    1. Brewster's Angle Grinder Silver badge

      Re: Can't neutron stars grow bigger from accretion?

      When neutron stars merge, as when anything merges, they tend to shed mass in spectacular fashion. (Astrophysics: the science for people who like big explosions seen from a safe distance.)

      Accreting material gets burnt in a jet of X-rays. I'm not sure you could get enough mass from the ash to bulk up the star. But if it got too heavy, it would suffer explosive collapse which might produce a black hole or might produce another neutron star.

      The real problem is we don't have a solid value for the upper limit for neutron stars. If Wikipedia is to be believed, this object is slightly lighter than the heaviest neutron star known (2.74M) And that's in pretty good agreement with the lightest stellar black hole (ibid - scroll down). But there's no theoretical minimum mass for a black hole and merging objects could, after shedding some mass, produce one that was, ahem. lighter than the upper limit for neutron stars. So it's probably a black hole

  6. David Hicklin

    Stars between 2 and 5 solar masses

    So what happened to them...where did they go ?

    1. tfb Silver badge
      Boffin

      Re: Stars between 2 and 5 solar masses

      I think that the mass gap is an observational thing rather than a theoretical thing: people spend a lot of time looking at binaries for which one companion is a neutron star or a black hole, and inferring the mass of that object (I think you can infer the mass of neutron stars which are not in binaries as well, but that doesn't work very well for BHs). And what they saw is that there are neutron stars which are lighter than about 2 solar masses, and black holes which are heavier, but they don't see anything in between.

      I think that the assumption is that the mass gap isn't real, and LIGO/VIRGO will fill it (and are starting to fill it with this observation).

  7. Claptrap314 Silver badge

    What about Quarks?

    No, not https://en.wikipedia.org/wiki/Quark_(Star_Trek), https://en.wikipedia.org/wiki/Quark_star

    Of course, a black hole of any particular mass is possible, but if faces with a theoretically reasonable, but hard to observe phenomenon verses a really, really, really rare thing, it seems odd to exclude the theoretically reasonable hypothesis.

POST COMMENT House rules

Not a member of The Register? Create a new account here.

  • Enter your comment

  • Add an icon

Anonymous cowards cannot choose their icon

Biting the hand that feeds IT © 1998–2020