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

What happens to you if you get pulled into a black hole?

  1. Jul 14, 2012 #1
    I know that because of the great gravity pulling at your feet much not as much at the upper half of your body you become like spaghetti but I want to know why this happens and what else could possibly happen.
     
  2. jcsd
  3. Jul 14, 2012 #2
    First of all I would like to point out that it is not just your leg getting pulled. It could possibly be your head too. This happens because whichever side of the body is facing the source of the gravity comes in contact with the source before the other side. Therefore getting pulled. For example, if a body is moving towards the black hole with its legs facing towards the black hole, the legs will come in contact with the gravity field of the black hole before the rest of the body and the spaghetti effect will take place. And as for other possibilities: I believe it is if you either go through the event horizon or dive right into the center of the black hole you wont face the spaghetti effect.
     
  4. Jul 14, 2012 #3

    phinds

    User Avatar
    Gold Member
    2016 Award

    The event horizon has absolutely zero to do with spaghettification. For small black holes you get spaghettified WAY outside the EH and for really really big ones you don't get it until WAY inside the EH.
     
  5. Jul 14, 2012 #4
    Yes I do realise that. What I meant was that there is a way of going inside a black hole without getting spagettified. I read it somewhere just don't remember where.
     
  6. Jul 14, 2012 #5

    phinds

    User Avatar
    Gold Member
    2016 Award

    What does "inside a black hole" mean to you? The only meaningful thing I can think of is "inside the event horizon" and I have already stated that you don't have to "do" anything to get inside the EH of a really large BH without getting sphagettified, it just happens that way and there is absolutely nothing you can do to avoid sphagetification outside the EH of a small BH.
     
  7. Jul 15, 2012 #6
    Because space time is pulled and distorted the person or object being "spaghettified" would have no sensation of it. The rest of the universe would look funny but you would be "just fine so far". (typical optimistic view)
    The heat and pressure on the "interior" of a black hole would disassemble the atoms that you are made up of and you would become a collection of sub-atomic particles in a sea of subatomic particles. The heat and pressure of a black hole is the closest thing to the universe at the very beginning of its existence. Too hot to form elemental particles in a dence soup that fused and decomposed sub-atomic particles continuously.

    The foregoing is not scientific fact - no one knows what happens inside a black hole but it is reasonable to assume that with the heat and pressure matter cannot exist. That leaves just energy - a lot of it to generate the mass of the black hole.
     
  8. Jul 15, 2012 #7

    Danger

    User Avatar
    Gold Member

    If the theoretical "split event horizon" exists, leading to a naked singularity, you can pass through it unimpeded as long as the distance from the singularity doesn't impart lethal tidal forces. Elsewise, you'll get stretched out like Reed Richards in an orgy.
     
  9. Jul 15, 2012 #8

    phinds

    User Avatar
    Gold Member
    2016 Award

    I cannot imagine how you can justify that statement. The sphagettification is real. How could you not experience it (for the little time you remain alive).
     
  10. Jul 15, 2012 #9
    We exist in the fabric of space time. If space time is distorted how would you know?
    We could be living in a six dimension universe that has been distorted by a black hole in three of the dimensions and so we only see the three we experience. There would be nothing within your frame of reference to tell you that something was wrong.
    An outside observer would see the "spaghettification" and may notice the time dilation but you wouldn't from your frame of reference.
    Light is pulled into the black hole in the same manner - it looks spaghettified too but it doesn't even have mass. It is, like you being pulled in along with the fabric of space/time. both of you are in "free fall" - there is no gravitational effect on the falling object.
     
  11. Jul 15, 2012 #10

    phinds

    User Avatar
    Gold Member
    2016 Award

    You are missing the point. Sphagetification is not caused by the gravity, it is caused by the DIFFERENCE in gravity between your head and your feet. Do you understand the concept of tidal forces?

    For a small black hole, you'll be ripped to shreds before you even get to the event horizon, so what happens in the "interior" of the black hole is irrelevant.
     
  12. Jul 15, 2012 #11
  13. Jul 15, 2012 #12
    You are missing the point: You are riding the space/time curvature in free fall. There is a difference in the space/time curvature from one point on your body to another but you are still locked into a space time reference.

    You are treating gravity as a force. It is not. It is simply the effect of bent time/space and objects following it.
    There is no gravitational effect in free fall. - think about it....
     
  14. Jul 15, 2012 #13
    If that were the case, we wouldn't experience tides on earth caused by the moon, and to a lesser extent, the sun.
     
  15. Jul 15, 2012 #14

    phinds

    User Avatar
    Gold Member
    2016 Award

    I HAVE thought about it. You don't seem to get the concept of tidal forces.
     
  16. Jul 15, 2012 #15
    You have to accept that light has no mass - right?
    If light has no mass and it is curved around a massive object then it cannot be a force acting upon a massless object - it has to be bent space/time like Einstein set forth in GR. It can't be both. Gravity either exists as a force or it exists as a curvature in space/time. If it exists as the effect of space/time curving then what an outside observer would see is the spaghettification process but the one in the local reference frame would be totally unaware that anything was happening to him. He would see the rest of the universe deforming. Add to this process the time dilation that takes over as you get closer to a massive object. For the person falling it would take very little time for the whole event to complete but the distant observer would see him "languishing" at the event horizon for a long time.
    There are two different frames of reference here and they are relative - or one is relativistic.
     
  17. Jul 15, 2012 #16

    Drakkith

    User Avatar

    Staff: Mentor

    This is incorrect. Tidal forces DO happen in many other cases, and the results range from benign to catastrophic. For example, the Earth's tides are caused by tidal forces arising from gravitation. Tidal forces can also rip stars apart in binary systems if a star gets too close to a neutron star or other small massive object. You are never "locked in" to a spacetime reference, whatever that is supposed to mean.

    The way spacetime curvature manifests itself is easily able to be described as a force in almost all cases. And I don't really know what you mean when you say "there is no gravitational effect in free fall". Free fall is a direct result of gravity, so it is itself a gravitational effect. Did you mean something else?
     
  18. Jul 15, 2012 #17
    Phinds is correct. Einstein's equivalence principle only holds in local coordinates. That is, over sufficiently small intervals of time and space. Otherwise, gravity has certain effects that acceleration does not (such as the tidal effect).
     
  19. Jul 15, 2012 #18

    Drakkith

    User Avatar

    Staff: Mentor

    I suggest you read this article on the effect: http://en.wikipedia.org/wiki/Spaghettification
     
  20. Jul 15, 2012 #19
    Jimmy,
    The tides are also generated by the curvature of space/time. Just as a ball that is thrown into the air is following the curvature of space/time back to the Earth.
    Gravity is not a force, it is an effect that we perceive from the curvature and velocity of the time/space around us.
    Paul
     
  21. Jul 15, 2012 #20

    Drakkith

    User Avatar

    Staff: Mentor

    Yes, tides are the result of gravity. They are also an example of weak tidal forces. Strong tidal forces can, and will, rip objects apart. See the article I linked in post #18 about it.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook