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A challenge: break the force barrier of nature

  1. Oct 12, 2003 #1
    A new claim has appeared in physics. It is claimed that there is a largest
    possible force, namely c^4/4G or 3 x 10^43 Newton.

    (The claim is made in the paper http://xxx.lanl.gov/abs/physics/0309118 )

    All my friends and acquantances have first said "wrong!"
    but then failed to produce a counterexample. Nobody was able to imagine
    a situation in nature where a higher value of the force appears.

    *Everything* is allowed: black holes, accelerators, supernovae, rockets,
    etc. Nobody has yet captured the prize of producing the first
    counterexample. There is even a prize of 20 Euros (:-) for the first
    counterexample, sponsored by two posters of the de.sci.physik
    newsgroup. ( 10 Euros are from myself )

    Does anybody know a solution?

    Tom Helmond
     
  2. jcsd
  3. Oct 12, 2003 #2

    jcsd

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    I've not read the paper but:

    The force felt by an object stationery over a Scwarzchild black hole is:

    |F| = (GMm/r2)/(1 - 2GM/rc2)1/2


    therefore as r tends to 2GM/c2 (the event horizon), |F| tends to infinity (as at r = RBH, the denominator is equal to zero).
     
    Last edited: Oct 12, 2003
  4. Oct 12, 2003 #3
    That is true, but the formula just says that no such observer
    hovering over the horizon exists.

    The claim means that the nearest place one can hover over a black
    hole is the place where the downwards force is c^4/4G.

    To find a counterexample, one would have to show that hovering nearer
    to the black hole is possible.

    Tom Helmond
     
  5. Oct 12, 2003 #4

    jcsd

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    Ok I've read the first part of the paper

    Christoph Schiller, though doesn't even derive the maximal force so it's difficult to work out what exactly he means as he only says it is so for a remote observer, yet the above formula shows that it is not so for a real observer.
     
  6. Oct 12, 2003 #5
    Hm, I beg to disagree. If there is a maximum force, it must be valid for all observers, even accelerated ones.

    But the challenge is to produce a force larger than the claimed limit. It is well known that it is not possible to hover above the horizon (after all this is a black hole); so this is NOT a counterexample to the claim.


    Tom Helmond
     
  7. Oct 12, 2003 #6

    jcsd

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    It is theoretically possible to hover at XRBH where X is greater than 1 as long as you have a power source and light from the point of view of a remote observer does hover at the event horizon.

    It's almost impossible to disprove without the original derivation that shows that this is the maximal force for all observers.
     
  8. Oct 12, 2003 #7

    jcsd

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    If you want to work this out a particle travelling radially outwards from a black hole with a velocity v will hover at a certain distance away from the black hole, r, it is then just a case of finding a v so that |F| is greater than the maximal force.
     
  9. Oct 13, 2003 #8
    I guess that the answer would be this: to produce a hovering
    in such a situation you would need an extremely powerful engine.
    The exhausts from that engine are so massive that the gravitation
    they produce cannot be neglected. The claim is that
    to produce a force larger than c^4/4G, these exhaust are so massive
    that they form a black hole on their own, which attracts the body that
    tries to leave the exhausts behind, preventing it from doing so.
    As a result, the hovering fails.

    Tom Helmond
     
  10. Oct 13, 2003 #9
    For a high force to appear near a black hole, a body needs to be
    hovering above it, as mentioned above. There are two was to do this:
    with a wire and with a rocket engine.

    A wire cannot maintain a force c^4/4G: if it did, lovering the wire by
    a distance d would create a black hole of diameter d at the other end.
    This is impossible.

    A rocket cannot either: its engine would have to spit out black holes
    in order to do so.

    Tom Helmond
     
  11. Oct 13, 2003 #10

    jcsd

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    Can you show that for me though, why exactly can a wire not theoretically maintain such a force, it's diffcult to disprove things that haven't been proved in the first place.
     
  12. Oct 13, 2003 #11

    jcsd

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    The formulas for the tnesion in the wire is in no way dependent on the properties of the wire.
     
  13. Oct 13, 2003 #12
    Try the inflationary force of the cosmological constant accelerating (a=[del]r/([del]t)2=~(1028cm/102sec2)) the universe mass (~1056gm).

    Finflationary=1082dynes >>3 x 1043Newtons=3 x 1048dynes.
     
  14. Oct 13, 2003 #13
    This is interesting! I never thought about this.
    Can you explain it a bit more?
    What acceleration is meant? In what sense
    can one say that all mass of the universe is accelerated?

    And why don't I feel this gigantic value?

    Tom
     
  15. Oct 13, 2003 #14
    Apart from the fact that no material is able to withstand this, the argument
    was just saying that even if the wire withstands this, strange things
    happen at the two ends that make the hole thing impossible:
    black holes must appear there.

    Tom
     
  16. Oct 13, 2003 #15

    jcsd

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    What I want is the mathematics behind this though.
     
  17. Oct 13, 2003 #16
    That is easy. A black hole has a radius of R=2Gm/c^2.


    A force of c ^ 4 /4G times a distance d gives the same energy E=m c ^ 2
    as the one that is contained inside a black hole
    of radius R=d, namely c^4 d / ( 2G ).


    Let us see if a larger force can appear.



    Tom
     
  18. Oct 13, 2003 #17

    jcsd

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    Can I have a more complete derivaiation esp. with respect to tension.
     
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