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Space Science

Monster Black Hole That 'Should Not Exist' Discovered in the Milky Way (cnet.com) 49

An anonymous reader shares a report: Astronomers think our home galaxy -- the Milky Way -- is practically bursting with black holes, with estimates of up to 100 million of the invisible beasts hiding across the galactic neighborhood. It was generally assumed these black holes could reach a mass of up to 20 times that of the sun, but the discovery of a "monster" black hole, with about 70 times the mass of the sun, has surprised Chinese astronomers. In a new study, published in the journal Nature on Nov. 27, a research team from the Chinese Academy of Sciences peered across the galaxy with the Large sky Area Multi-Object fibre Spectroscopic Telescope (Lamost), based at Xinglong Observatory in China. Black holes don't emit light, so astronomers have to get crafty when they go hunting for them.

Usually, this involves looking for signs a black hole is feasting on a nearby star or the gas and dust that swirls around them. If the black hole isn't feasting and if it isn't surrounded by bright gas and dust, it becomes a little trickier to locate. But, using Lamost, the team examined the movement of stars across the sky, searching for those that seemed to be orbiting an invisible object. Follow-up observations with telescopes in Spain and the US helped the researchers discover a star about eight times bigger than the sun. Intriguingly, it was orbiting a "dark companion": The monster black hole, dubbed LB-1. "Black holes of such mass should not even exist in our galaxy, according to most of the current models of stellar evolution," said Liu Jifeng, astronomer at the National Astronomical Observatory of China and first author of the study, in a press release. "LB-1 is twice as massive as what we thought possible. Now theorists will have to take up the challenge of explaining its formation."

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Monster Black Hole That 'Should Not Exist' Discovered in the Milky Way

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  • them are small holes (Score:3, Informative)

    by gtall ( 79522 ) on Thursday November 28, 2019 @02:14PM (#59467358)

    A monster black hole is something over 1000 suns. There's one in Messier 87 that's 7 billion suns. The ones they are talking about are small ones created by star collapse.

    • by Quantum gravity ( 2576857 ) on Thursday November 28, 2019 @04:00PM (#59467562)
      Messier 87 is an SMBH, a supermassive black hole. Astronomers have also started talking about ultramassive black holes (UMBH), with more that 10 billion solar masses. They are associated with quasars. There probably is a max size for black holes of about 50 billion solar masses or maybe 100 billion masses if two such monster collide.
      • A physical limit (do they go super-black-nova?) or a statistical "limit" based on modeling cosmological evolution?

        If the latter, why is the probability function of further merger so abrupt?

    • by oneiron ( 716313 )
      Your comment is misleading. Monster is not a technical term. Super-massive is the technical term. Monster is just a generic layperson's way of saying it's bigger than others in its particular vicinity or circumstances.
      • Right. I had a monster hamster once. It was twice as big as the other hamsters.

      • by iNaya ( 1049686 )
        I don't think many laypersons would think that 80 solar masses were "monster" when there exist black holes of over 1000000 solar masses; as long as they were aware of both facts.
        • by oneiron ( 716313 )
          First, the distinction I was making is between layperson language compared to technical language...not a hypothetical phrasing used by some random idiot compared to an expert in the field. Even still, why be so selective about the basic facts supporting the hypothetical phrasing from the random idiot? It's a stellar black hole that's twice as large as the predicted maximum and 3x as large as the vast majority of such black holes. In its category, that's a monster.
    • It's expected there are very large black-holes at the center of galaxies. However, there is no known reason for such to exist in typical "suburban" areas of a galaxy. When large stars die, they blow most of their mass away, and are not statistically likely to encounter other black holes afterwards.

      Thus, if such large suburban black-holes are common, it would probably mean either theories on large star death are wrong, or some unknown process is merging holes.

    • You're correct. In fact they have imaged more than one at this point which are in that range. (100,000-billions of solar masses)

      The article was not written by a scientist, but they failed to grasp how a solar mass black hole differs from the theoretical/physical concept of a black hole. Solar mass black holes are a certain variety of black hole, with a certain lifecycle. Since they form from stars, scientists base their properties on what we know about stars, and how they collapse into black holes. If there

  • They found another? (Score:3, Informative)

    by WoodstockJeff ( 568111 ) on Thursday November 28, 2019 @02:16PM (#59467364) Homepage

    https://science.slashdot.org/s... [slashdot.org]

    Delayed post because pointing out a dupe doesn't take long enough for /.

    • by careysub ( 976506 ) on Thursday November 28, 2019 @05:48PM (#59467824)

      This isn't a dupe. This is a different detection of another black hole by an entirely different method (optically with LAMOST, not gravitationally as with LIGO/VIRGO) that lies in the 50-120 solar mass range.

      Both both stories falsely use terms like "impossible" and "should not exist" when at most "unexpected" should be applied.

      The real story here is that we know of no mechanism that will produce black holes in this range directly. Pair instability blows up stars in the necessary range so that they cannot form black holes. But notice I said directly. Smaller black holes, so two 40 solar mass black holes could merge and produce a 70 solar mass black hole (with 10 solar masses being radiated away as gravity waves). So we already know how such black holes can form.

      • I'm confident that your waving away 10 solar masses due to gravitational waves is incorrect. The universe hasn't been in existence long enough for even a tiny fraction of that mass loss to occur.

        Hawking radiation is the typical way we describe black holes as 'evaporating' though loss of energy, and even though that effect massively dominates gravitational waves, we're still talking trillions of years to lose 1 solar mass. Again, longer than the universe's age.

        • This has nothing to do with Hawking radiation and entirely to do with the fact that in order for two black holes to merge, the gravitational potential energy between them has to go somewhere. It goes into gravitational waves. Two merging black holes will emit roughly 5% of their mass [aps.org] as gravitational waves.

  • by 93 Escort Wagon ( 326346 ) on Thursday November 28, 2019 @02:20PM (#59467374)

    “But Westley, what about the BHOUS’s?”

    “Black Holes of Unusual Size? I don’t believe they exist.”

    SLURP...

  • Doubts exist ... (Score:5, Informative)

    by kbahey ( 102895 ) on Thursday November 28, 2019 @02:41PM (#59467426) Homepage

    This is not a done deal yet.

    Doubts exist [skyandtelescope.com], so more observations will confirm or refute that it is a 68 solar mass black hole, systemic errors, or something else.

    • by gl4ss ( 559668 )

      wouldn't the easy explanation just be that it swallowed a red giant sometime in the past? and the current orbiter was part of some dual system with that star?

  • We've "watched" mergers with LIGO, and some of those ended up in this 70-80 M(sun) range. Why is it surprising that we've found one in our own galaxy? If models haven't been planning for these to show up, that's distinctly on a lack of imagination because we've known for a few years now that these objects exist in other galaxies, and there's no good reason to believe they don't also exist in ours.

  • by qeveren ( 318805 ) on Thursday November 28, 2019 @04:27PM (#59467612)
    I thought this was astrophysics, where anything in the same order of magnitude was "eh, basically equal"?!
  • by charlie merritt ( 4684639 ) on Thursday November 28, 2019 @04:45PM (#59467668)

    I've read that stellar BHs shouldn't be larger than some X. Why not? X+X=2X-(gravity wave energy) and we are picking up regular collisions of black holes with gravity wave detectors. To me it seems that there may be a smallest possible bh but anything between that and the very most massive should be possible with simple addition.

    • by tsuliga ( 553869 )

      What's interesting is that I thought I read that that the large hadron collider may be creating black holes, but they evaporate very quickly due to Hawking radiation.

      But this would mean there is an entire spectrum of black holes that exist for some X amount of time.

      So no physicist should be surprised on the size of a black hole. They are all sizes for some finite amount of time. From mere milliseconds to billions of years.

      I guess the title needs to be impressive and unusual to get eyes and clicks.

      If you agr

    • It's mostly down to gravitational mechanics and statistics. Stars tend to form either by themselves or with 1 or 2 other stars. Any more than that and the chaotic nature of gravitational dynamics means either stars end up being ejected, or they collide together (even in trinary star systems the third star is usually quite far from the other two so it acts more like two single body systems, kind of like how the earth and moon orbit the sun together). Each star obeys standard stellar dynamics, so you can only

  • It should exist. It does exist. Therefore its simply "we don't know why". Science should not be treated as a religion.

  • but it's a shade of yellow associated with the protests in Hong Kong so the Communist Party censored it.

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