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B What would happen if 6 black holes surrounded a planet?

  1. Dec 28, 2016 #1
    Hey, was trying to think of what the safest possible place in existence would be and got to thinking of a planet surrounded by 6 blackholes of equal size.
    Say the blackholes met around this planet at the precious same time and are held in equilibrium, is there any particular reason that a planet couldn't survive in the area between?
    (One above, one below and one on each side, as opposed to in a circular pattern.)

    Excluding the planet for a moment, could 6 black holes be held in equilibrium by the force of it's neighbors?

    No interest in discussing the improbability and I understand that doing the maths on a question like this is laughable, so, just based on your understanding of blackholes, is this something that is even possible?

    Thank you!
    <3 Phill
     
  2. jcsd
  3. Dec 28, 2016 #2

    Vanadium 50

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    By what, exactly? What keeps them from all crashing in on each other?
     
  4. Dec 28, 2016 #3

    Nugatory

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    As long as you don't fall in, the gravitational effects and orbital dynamics of a black hole are the same as you'd find outside an ordinary star of equivalent mass - for example, if our sun were to collapse into a black hole the orbit of the Earth would be unaffected.

    So any orbits you can set up with six ordinary masses you can set up with six black holes.
     
  5. Dec 28, 2016 #4

    Vanadium 50

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    How do you make a stable orbit for the two BH's not in the equatorial plane?

    Also, he didn't say "orbit", he said "equilibrium". How does that happen?
     
  6. Dec 28, 2016 #5
    I was envisioning something like them all being of the precise same mass and they all happen to be on course to crash into each other at the precise same time, to the extent that the point of crash is so undecided that an equilibrium is reached in the crash not actually occurring.
    I am thinking of a pingpong ball being sucked into a vacuum cleaner and then adding another vacuum cleaner of the same suction value that then holds the ball between the two vacuums instead of having it crash into either of them. Applying that type of logic to having multiple blackholes meeting at the same time/point at the perfect angle.
    Kinda like each blackhole preventing the others from reaching the central point.

    It makes sense to me in mild autism town, am curious as to how it holds up to scientific scrutiny.

    Kind regards,
    Phill
     
    Last edited: Dec 28, 2016
  7. Dec 28, 2016 #6
    Greetings from mild autism town.

    The reason you are being asked "how" is that black holes are all about mass and gravity,. and gravity is always an attractive force. Your vacuum cleaner/ping pong ball example is bad because all the suction from the vacuum cleaner is applied to the ping pong ball, whereas all the gravity from the black hole is not applied to the planet. The six black holes would attract not just the planet, but also each other, and they would crash into each other.

    So, let's assume that you somehow have stopped the black holes from advancing toward each other. Could a planet survive in the space between?

    No.

    Assume the following - six one solar mass black holes, surrounding an Earthlike planet at a distance of our moon's orbit (so you can legitimately say "this planet is surrounded by six black holes). The escape velocity of each of those black holes would be 832 km/s for the side of the planet facing the black hole, and 812 km/s for the side of the planet facing away from the black hole. For comparison, the escape velocity of the Earth is 11.2km/s.

    The planet would experience horrible tidal forces - The atmosphere would be ripped away, the surface stripped bare, and the denuded body would be torn into chunks. Those chunks would then be torn into bits. Eventually those bits would be torn into even smaller bits and those bits would be superheated and absorbed. To call it "bad" for the planet would be an understatement.

    Please do not try this at home.

    http://www.calctool.org/CALC/phys/astronomy/escape_velocity
    (mass of one sun, distance of 238,000 and 250,000 miles, representing a 12,000 mile diameter planet)
     
  8. Dec 28, 2016 #7

    Vanadium 50

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    Is that what you mean? That since there will be a 6- or 7-way collision all at once that the collision will not occur at all? Nature doesn't work that way, I'm afraid.
     
  9. Dec 28, 2016 #8
    Cool cool, thank you all for your time, back to the drawing board!
    Kind regards,
    Phill
     
  10. Dec 28, 2016 #9
    Just wondered if the number six has any significance for this question.
    You could say five or seven, does it matter?
     
  11. Dec 28, 2016 #10
    The line of thought was from the amount of sides of a cube. Figured that would be sufficient to surround a planet.
     
  12. Dec 28, 2016 #11
  13. Dec 28, 2016 #12

    Vanadium 50

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    No, it's not worth considering. This idea is totally wrong, and you do PF a disservice by encouraging it.
     
  14. Dec 28, 2016 #13
    Hmm sorry, I thought baez was considered to be a sound reference in many regards.
    What I meant was that a cube is not the only way to envisage a symmetrical arrangement of points.
     
  15. Dec 29, 2016 #14

    Vanadium 50

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    I am not denying the concept of Platonic solids. IK am denying the concept of masses arranged as vertices of Platonic solids not having gravity. As I said, that idea is totally wrong, and you do PF a disservice by encouraging it.
     
  16. Dec 29, 2016 #15

    mfb

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    The original question has been answered: no it does not work at all. Please make a new thread for discussions about Platonian solids or other unrelated topics.
     
  17. Dec 29, 2016 #16

    Doc Al

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    This is a good point to close this thread.
     
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