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Black Hole Found Inside Globular Cluster

Posted by CowboyNeal on from the not-so-creamy-centers dept.

acidrain writes "Contrary to the prediction of some computer models, scientists have found a black hole resting peacefully in a dense nest of stars called a globular cluster. Previously discovered black holes are either similar in size to a large star, or super massive holes which are millions of times bigger than a star is able to remain stable. This finding indicates there may be an intermediate size range of holes residing within these star clusters."

9 of 73 comments (clear)

  1. Large by mass by MillionthMonkey · · Score: 4, Informative

    The singularity is a point but the Schwarzchild radius around it is directly proportional to mass. One earth mass is equivalent to something like a few cm of Schwarzchild radius.

    Inside the Schwarzchild radius everything falls into the hole regardless of velocity, no exceptions.

  2. warning required? by PTBarnum · · Score: 4, Funny

    The important question is, does this black hole have a warning label?

    WARNING: do not drop spaceship keys into black hole

  3. Re:Yet Another Black Hole by Guppy06 · · Score: 3, Funny

    "How many black hole discoveries do we need to announce before they no longer become news?"

    Black Hole Found Inside New Jersey.

  4. I wonder if time is dilated there... by Progman3K · · Score: 5, Interesting

    If you lived on a planet of the star closest to the black hole, would the passing of your time be measurably different from ours?

    --
    I don't know the meaning of the word 'don't' - J
    1. Re:I wonder if time is dilated there... by shma · · Score: 5, Informative

      According to General Relativity, the passage of time at a location depends on the gravitational field there. So, for instance, if the sun were to collapse into a black hole, there would be no change in the passage of time here. You would have to pass within a few Schwarzschild radii to see an effect (The Schwarzschild radius for the sun is about 3 kilometers, while Earth is 150 million km from the sum)

      --
      I came here for a good argument
    2. Re:I wonder if time is dilated there... by MillionthMonkey · · Score: 3, Informative

      If you lived on a planet of the star closest to the black hole, would the passing of your time be measurably different from ours?

      Measurably but imperceptibly different from ours. But for the planet, no different than before. The gravity along a planet's orbit would be unchanged by the star's collapse. If it survives the red giant phase or the explosion, a planet's orbit won't be expected to change. By me, anyway.

      The interesting spacetime effects that we associate with black holes take plase close to the singularity at the center, in regions of space that were formerly buried under the original star's surface. It would be hard to explain how you could find a planet bound in a stable orbit in there now. In the absence of gravity from a third body, things will either strike the singularity or take a mostly hyperbolic trajectory past it.

      And be careful what you mean when you say "would the passing of your time be measurably different from ours" because some people take that to mean that you'll look down at your watch and see the hands moving faster or slower than usual. You'll always experience proper time for your reference frame, which basically means you'll never see that. The difference is with clocks far away from the black hole, which tick more quickly than clocks closer to it.

    3. Re:I wonder if time is dilated there... by rufty_tufty · · Score: 4, Funny

      "The article says the black holes are "resting" inside the globular cluster"

      Next you'll be telling me its pining for the fyords!

      --
      "The weirdest thing about a mind, is that every answer that you find, is the basis of a brand new cliche" -
  5. Re:Yet Another Black Hole by cciRRus · · Score: 4, Funny

    Actually there is just one; the rest were dupes. =)

    --
    w00t
  6. Re:Black hole do not change their mass by SuiteSisterMary · · Score: 5, Interesting

    (note: this is from memory)

    Our sun is defined as 'one solar mass.'

    Very basically, a star's tendancy to collapse in on itself is countered by the fact that it's a big old nuclear fireball. As it runs out of hydrogen to burn, it starts to collapse in on itself again, until it starts burning helium. Once the helium is gone, it starts to collapse again.

    Any given star of less than 1.4 solar masses will stop collapsing and turn into a white dwarf, due to the fact that it's gravity isn't enough to overcome the repulsion of electrons. (If this white dwarf gets some new material, say, by having a red giant close enough that it can gather material from it, it will explode, giving us a supernova.)

    Any given star of greater than 1.4 solar masses but less than 3 solar masses will overcome this, but get halted by inability to squish neutrons together.

    Anything bigger than 3 solar masses will overcome neutron degeneracy, and collapse even further into a black hole.

    --
    Vintage computer games and RPG books available. Email me if you're interested.