Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Where do things go after they were sucked by a Blackhole?

  1. May 21, 2015 #1
    I'm just wondering if a space craft or any kind of matter was swallowed by a blackhole , where does the debris go? I know that it will disintegrate, but even the gravity in there is very strong will there be debris left? If there is, Will it go to other dimension or what?

    Thanks,
    Austin
     
  2. jcsd
  3. May 21, 2015 #2

    Chronos

    User Avatar
    Science Advisor
    Gold Member

    It's too late to hold much hope for fragments to escape the gravity well once it get close enough to be tidally disrupted. The debris then joins the accretion disc, otherwise known as the buftet line, to feed the black hole. The only way to escape the accretion disc is thru jets where a forrtunate few particles can be accelerated to and escape at relativistic velocities. If a sub atomic particles qualify as 'debris', this is the only know way to escape such an encounter.
     
  4. May 21, 2015 #3

    phinds

    User Avatar
    Gold Member
    2016 Award

    If "swallowed" by a black hole means "crossed the Event Horizon" (and I can't think what else it could mean) then the object becomes part of the singularity at the center of the black hole. We don't know what the singularity is but may know when a theory of Quantum Gravity is developed.
     
  5. May 21, 2015 #4
    If this is the case, let's say the black hole is keep on swallowing things, and all particles and debris will occupy the center of the black hole? will it affect strength of the particular black hole? or it may result to a new cosmic environment. no?
     
  6. May 21, 2015 #5
    I'm just wondering for the fragments, where would they go if they can't escape the gravity. IF they will occupy the center of the black hole, isn't it a best place for a new evolution of cosmic activity? Because as what I've understand of black holes is that they are compose of energy (Dark energy or Vacuum Energy). And I believe there is no such thing as infinite energy. So there might be some point that it will slowly loose its gravity.
     
  7. May 21, 2015 #6

    phinds

    User Avatar
    Gold Member
    2016 Award

    Well, then what you have heard is nonsense.
     
  8. May 21, 2015 #7

    phinds

    User Avatar
    Gold Member
    2016 Award

    Yes, it will increase the gravitational attraction of the black hole. I have no idea what you are talking about when you say "new cosmic environment".

    I think you should read some real physics instead of pop-science nonsense.
     
  9. May 21, 2015 #8

    Drakkith

    User Avatar

    Staff: Mentor

    Black holes are made up primarily of matter, but energy (in the form of light and the kinetic/potential energy of the matter) also contributes. Note that gravity does not require the expenditure of energy to function. In other words, the only way for the black hole's gravity to lessen in strength is for the black hole to lose some of its mass. The only way for this to occur is through hawking radiation.
     
  10. May 22, 2015 #9
    Is it possible for a 'Black Hole' to reach a critical mass- such as in an exploding star?
     
  11. May 22, 2015 #10
    I thought the generation of gravity waves reduces energy.

    Edit: hmm I just read the wiki on those waves, and it says it causes orbital decay. I don't think that means less energy (mass) for the body, but for the "system" as a whole. Though such a system is likely to eventually become a single body and it had dissipated some energy "via gravity".

    Also frame dragging, I'd think that's a clear example of weaker gravity from a body losing energy (mass).
     
    Last edited: May 22, 2015
  12. May 22, 2015 #11

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    You're confusing two different concepts here.

    1. "Critical mass" is a term which describes the amount of nuclear material which, when brought together, will sustain a nuclear chain reaction where the atoms in the critical mass are split by atomic fission:

    http://en.wikipedia.org/wiki/Critical_mass

    2. Stars don't explode because they reach some critical mass. Stars create energy by using atomic fusion, rather than atomic fission, so there is no critical mass beyond which they will explode. Stars explode for a variety of reasons. See supernova:

    http://en.wikipedia.org/wiki/Supernova
     
  13. May 22, 2015 #12

    Chronos

    User Avatar
    Science Advisor
    Gold Member

    There is no theoretical mass limit for a black. IIRC the largest known black hole has a mass around 20 billion times that of the sun. As Drakkith noted, the only way they can shed mass is via Hawking radiation and that process is well beyond painfully slow.
     
  14. May 22, 2015 #13
    How is the "Penrose Process" not also a way in which a BH could lose energy (mass)?
     
  15. May 22, 2015 #14

    Chronos

    User Avatar
    Science Advisor
    Gold Member

    The hypothetical penrose process extracts energy from outside the event horizon, so the black hole does not decrease in mass via any such mechanism.
     
  16. May 23, 2015 #15
    Hmmm...I'm not sure about the equally Hypothetical Hawking Radiation process (or how accepted it is either, though agree it would have been "reviewed" far more than the Penrose Process), but the Penrose Process decreases the energy of a rotating black hole, is this splitting hairs between mass/energy loss and a decrease in gravity? Since you specifically said the penrose process does not decrease a black holes mass.

    Yes it begins outside the EH, but part if the process is a piece of the "attracted object" must "fall" past the EH.

    Is the distinction between "rest mass" and energy with respect to gravity relevant for a black hole? When I read a black hole is 20 million time more massive than our sun, does that exclude kinetic energy, pressure ect? I'd guess that value is derived from the observed gravitational effect of the black hole. I can't imagine the calculation includes an estimate of the radiation absorbed because "Oh that's just momentum, not mass. We want to know how massive it is."


    Just to make clear my point is there isn't only one theoretical way for a black hole's gravity to lessen than it losing mass. In turn it leads to having to say only hawking radiation theorizes a way for a black hole to lose mass, since it was previously said the only way for a BH to have reduce gravity is by losing mass. (despite have made the comment that light, kinetic, momentum contribute to a bh's gravity)

    What's more, I'm sure if I read about hawking radiation...it will be about radiation...not ejection of matter (rest mass) from the within the black hole. And again it just seems pointless making a mass/energy distinction in this context of changes in gravity of a black hole...why not just call all of it energy?
     
    Last edited: May 23, 2015
  17. May 23, 2015 #16
    We cannot know for sure, but presumably it is crushed into the singularity. Some do not think an actual singularity can exist, based on quantum mechanics, so the center of the black whole is the smallest meaningful volume, the Planck volume. Either way, the space craft is crunched out of existence.
     
  18. May 24, 2015 #17
    You can also consider a hypothetical phenomena called mass inflation that occurs at the Cauchy horizon (or inner horizon) of charged (Reissner–Nordström) bh's, rotating (Kerr) bh's or black holes that have both charge and spin (Kerr-Newman). At the Cauchy horizon (r-) is predicted to be a 'weak' singularity where gravity increases infinitely in a Dirac Delta function, as apposed to a Schwarzschild singularity where gravity (and tidal forces) increase exponentially the closer you get. This seems to be caused by a possible number of things. For a rotating black hole, matter/energy is flung out by a central spinning ring singularity, the outfalling matter meeting the infalling matter creating the Cauchy horizon, this is also predicted to recreate time-like worldlines within the Cauchy horizon. For a charged black hole mass inflation is caused by electrostatic repulsion. Another way of looking at this is at the outer horizon (r+), outgoing light rays are infinitely redshifted while ingoing light rays are infinitely blueshifted, this balance means the spacetime stays smooth, but at the inner horizon, both ingoing and outgoing lightrays are blueshifted, causing the pinch in spacetime. It's also predicted that gravity waves that fall back into a charged/spinning black hole contribute to mass inflation. If a spaceship is robust enough, it might be able to pass through the weak singularity though the Cauchy horizon is sometimes referred to as the boundary of predictability and the Kerr-Newman case is predicted to be unstable. Here is the old PF library entry for mass inflation which also has links to some papers-

    what is mass inflation?

    Below is a link relating to mass inflation in charged black holes-

    http://jila.colorado.edu/~ajsh/insidebh/realistic.html#inflation

    If you also do a search in the forums, you should find various discussions on the subject.
     
    Last edited: May 24, 2015
  19. May 24, 2015 #18
    ^^ that's some weird stuff

    We need to do something about these black holes, they're making a mess of spacetime :( lol
     
  20. May 24, 2015 #19
    One idea proposed by Stephen Hawking to satisfy the law of conservation of matter is that the black hole has a life span and when it dies and evaporates everything it has is released back into the Universe, but since there is no way to look into a black hole (which would be nice) what actually happens to the matter inside is a mystery, it may be thrown into other regions of spacetime, no one knows.
     
  21. May 24, 2015 #20

    Drakkith

    User Avatar

    Staff: Mentor

    I'm not aware of such a law.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Where do things go after they were sucked by a Blackhole?
  1. Where will it go? (Replies: 4)

  2. Where do neutrinos go? (Replies: 2)

Loading...