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

Twisting space

  1. Jul 17, 2003 #1
    What is being suggeted when it is proposed that space is curved?
  2. jcsd
  3. Jul 17, 2003 #2
    General Relativity does not have a causal mechanism for the force of gravitation. Curved space is simply a measurement of a property of space unknown to the theory of general relativity. A mapping system for the effect of a g-field...but ignore me please I am a "crack-pot".

    Note: I am not describing the theory of relativity from within the hermetically sealed system. This is an "outsiders" viewpoint.
    Last edited by a moderator: Jul 17, 2003
  4. Jul 17, 2003 #3


    User Avatar
    Science Advisor
    Gold Member

    One example that immediately springs to mind is that the shortest distance between two points is no longer a straight line but a curve, also you'll find that the angles of shapes drawn in curved space add up to different values than the same shapes in flat euclidian space.
  5. Jul 17, 2003 #4
    how could a curved path between 2 objects be shorter than a straight one?
  6. Jul 17, 2003 #5
    Could be because if you sent an object on it's merry way in whatever direction in space - It would follow a curved line. This would be in response to whatever gravitational influence is the greater of all the other gravitational influences. If you could have a situation where all gravitational influences were equal from all directions - You could send an object in a straight line, and boldly say that space is not curved.

    If my statements are not true - Then space is curved.
  7. Jul 17, 2003 #6


    User Avatar
    Science Advisor
    Gold Member

    Think of two points on the surface of a globe, you'll notice that the shortest path between the two is a curved one as well (this fact was well known to sailors in days of yore).
  8. Jul 17, 2003 #7
    It depends arbitrarily on the system in which the distance is measured.
  9. Jul 17, 2003 #8


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    The "curvature" of space is a metaphor for the behavior of spacetime (e.g., in the presence of matter). For example, a gravitational field around some mass can be visualized as a well...like a drawdown curve around that object. The trajectory of an object that enters that drawdown area (enters the slope of the well) is altered accordingly based on the strength of the field (the slope of the curvature).

    Given that Relativity only has 3 dimensions of space, it is not proposing a physical curvature of 3D space into a higher, 4th dimension of space. (although maybe into the 4th dimension as Time, but I'm less clear on that)
  10. Jul 17, 2003 #9


    User Avatar
    Science Advisor
    Gold Member

    Phobos, it's more than a metaphor, the curvature of space in GR works exactly the same way as if it were curved into a 4th higher dimension of space (some people have a hard time understanding that though space is curved this way it doesn't at all imply that a fourth dimension of space exists, tho').
  11. Jul 17, 2003 #10
    I'm inclined to think of gravity like this.


    And that there is no curvature of space. I think of gravity as a wound out wave in a spiral fashion. The wave is the particle. Half of the wave (particle) is localized and the other half is not. The part that is not is the gravitational aspect of the wave (particle). The localized part of the wave is what we see as a particle (the localized wave).
    Last edited by a moderator: Jul 17, 2003
  12. Jul 17, 2003 #11
    So it is a metaphor that works!!!

    It still fails to explain the force of gravity in its causal details.
  13. Jul 17, 2003 #12

    In Sorce Theory, gravity is a refraction of the internal wave systems of the atom in response to an over-riding density gradient (g-field) in the unified field.
  14. Jul 17, 2003 #13


    User Avatar
    Science Advisor
    Gold Member

    The curvature of space is the causal explantion of gravity!!!!!!!!

    When your looking at curved space in GR it is exactly the same as looking at a curved topology which is a lot stronger relationship than the word 'metaphor 'implies'.
  15. Jul 17, 2003 #14


    User Avatar

    Staff: Mentor

    The problem with that is that it does not explain the behavior of light, ie how light can be affected by gravity if it is massless.
  16. Jul 17, 2003 #15
    Your interpretation of mass is likely different than mine. Light on the loose coming from say another star ... I see as a wave that is planar in nature. Sort of like a pizza getting made at the parlor. The dude tosses the dough in the air with a spin - It grows in size. With a photon it never stops growing in that planar fashion. At least not until it gets localized, partially localized, (acted on?). A free ranging Photon will be affected in more or less the same way as two gravitational field lines affect each other.
  17. Jul 17, 2003 #16
    It is the explanation of the effect of the causal mechanism. It is not an explanation of the mechanism itself. This is common knowledge that the mechanism of gravitation still is a mystery in the standard model.

    Can you tell me exactly HOW mass curves space?

    It is simply a map. Nothing more.
  18. Jul 17, 2003 #17


    User Avatar
    Science Advisor
    Gold Member

    Mass curves space via gravity (I know you're not going to be happy with that but GR in terms of explaining the causes of gravity is a great improvemnt oin Newtonian physics).

    The fact that gravitational fields produce the exact same results as curved space means it is perfectly correcvt to say mass curves space.
  19. Jul 17, 2003 #18


    User Avatar
    Science Advisor
    Gold Member
    2015 Award
    Dearly Missed

    The first question is "What is being suggested when it is proposed that space has zero curvature?"

    Around 1820 it occurred to Carl Gauss to wonder about this and the answer he came up with was to do an experiment to see if the sum of the interior angles of a large triangle---determined by surveying instruments----would come out to be 180 degrees.

    Would this satisfy you, as meaning that some region of space is uncurved, or has zero curvature?

    Before asking if space is curved in some region it would be good to know what exactly do you mean by saying that it is not curved or flat. I think this triangle idea of Gauss is very good, how about you?

    If we measure a big triangle and the angles sum to more than 180 degrees we could say that the curvature is "positive".
    Or if it came to exactly 180 degrees we could say it the curvature was zero. Is this OK?

    With that idea of curvature, there is no reason to suppose space is flat in any region where there is matter and indeed if we put 3 satellites in orbit around the sun in a rougly equilateral triangle and had them flash laser beams back and forth to make a triangle and if we measured the sum of the interior angles very accurately it would most likely come out to be more than 180 degrees.

    My post here is in response to the question asked by Mitch Bass at the start of the thread, so I will wait to see if he is still around and wants to reply to my post. If he doesnt that is fine and I will just let it be.
    Last edited: Jul 17, 2003
  20. Jul 17, 2003 #19
    This depends on your view of space. My personal view is that space can't be curved, because it isn't there. One could expect the same results from a gravitational field or curved space, but one of em has to be wrong. Right?
  21. Jul 17, 2003 #20
    I agree that it is an improvement over newtonian gravitation, but you are correct I am not at all convinced that the mechanisms of gravitation have been explained by relativity, especially when I have seen a good causal explanation.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Twisting space
  1. Inertia in space? (Replies: 13)

  2. Space sounds? (Replies: 10)