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Thread: Directional Gravity?

  1. #1 Directional Gravity? 
    Forum Cosmic Wizard icewendigo's Avatar
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    Is there any indication that gravity would be slightly shifted(doppler-like) in front and behind earth's path if earth was orbiting much faster than it is now(lets say 0.8 c), so that nearby in front of earth's path gravity would be slightly stronger initialy but diminish faster than usual as you get further out in front of earth's path, while behind earth gravity would be weaker than usual yet diminish with distance less than usual?


    Forces
    The universe would make more sense to me if a force that is stonger than the strong force would act as a repulsive force on an even smaller scale, while a repulsive force even weaker than gravity acted on a much larger scale. Is there any indication that such extra-standard forces exist?


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    Forum Ph.D. william's Avatar
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    I don't know of any force that can be Doppler shifted.

    But... perhaps you might like to read up on the Lense-Thirring effect (frame dragging).

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    Forum Cosmic Wizard icewendigo's Avatar
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    does gravity's effect travel at the speed of light?
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    Quote Originally Posted by icewendigo
    does gravity's effect travel at the speed of light?
    Light, which travels at the speed of light, is affected by gravity.
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    It's interesting that you should be asking these questions. I just happen to be working on something related to this in reference to the time that it should take gravity to travel from one body to another at the speed of light. In this case, the other body should not be pulled toward the current position of the first, but toward a previous position in its orbit. The following equations demonstrate how the force should depend on the direction of travel and the total difference in velocities between the two bodies.

    Imagine first two bodies that are at rest and emitting lines of force in pulses. We can consider this as the amount of force that would act on the other for the given time between each pulse. If we double the pulse rate, we cut the force for each pulse in half. The rate for two bodies at rest will remain constant.

    Now let's consider what happens when we put one of the bodies in motion (v) relative to the other, which is still at rest. Since the pulses contain the force, if the pulse rate goes up in this case, the force goes up between them. If it goes down, then, the force is less. In other words, the force is directly proportional to the pulse rate. The distance where the line of motion of the moving body becomes perpendicular to the other body we will label d. The distance from this perpendicular point to the actual position of the moving body we will call x. The body is moving toward the perpendicular point. The actual distance from the current position of the moving body to the position of the other body is then z=(d2+x2)1/2=d(1+(x/d)2)1/2. Let's say that when the body is at x, it emits a pulse. The pulse travels the distance z to the other body in the time z/c. The body then continues moving along its line of motion until it releases another pulse. This occurs at x'=x-v/p. The ratio of the difference between the time that the other body receives the first and second pulses for a body in motion and a body at rest will then also be the ratio of the forces in each case. For bodies at rest in relation to each other, the difference in times (the time between pulses) is (t'+1/p)-t=1/p, since t=t'=z/c. For a moving body, it is (t'+1/p)-t=(z'/c+1/p)-z/c. The ratio of forces is then [(z'/c+1/p)-z/c]*p.

    If we break this formula down (I won't go through all of the in-betweens here), we get (pd/c)[(1+(x/d-v/pd)2)1/2-(1+(x/d)2)1/2]+1. Let's make v/p equal to ux, where u is some coefficient, and y=(x/d)2. We now have (pd/c)[(1+y(1-u)2)1/2-(1+y)1/2]+1. Now let's make (1-u)2=j. We get (pd/c)[(1+yj)1/2-(1+y)1/2]+1. Now backtracking a little, since p=v/ux and u=j1/2-1, then p=v/(j1/2-1)x. Substituting in, we get [dv/(j1/2-1)xc][(1+yj)1/2-(1+y)1/2]+1. Furthermore, since x/d=y1/2, we now have [(v/c)/(j1/2-1)y1/2][(1+yj)1/2-(1+y)1/2]+1.

    The trick now is to increase the pulse rate to as high as possible to similate continuous flow. As the pulse rate increases, the force per pulse decreases in proportion so that the total force remains the same. As the pulse rate increases to infinity, the value of u approaches zero and j approaches one. For an extremely large pulse rate, we achieve that ratio of forces for when the body is precisely at x and travelling at the velocity v toward the perpendicular point. The numerator and denominator in the formula both approach zero for this instant. The limit for j=1 in its simplest form will give the result we need.

    We now have [(v/c)/(j1/2-1)y1/2][(1+yj)1/2-(1+y)1/2]+1. We must find the limit for when j appoaches one. Don't ask me how I found it (thank goodness for U-Basic), but (1+yj)1/2-(1+y)1/2 reduces to (j-1)/[(2/y+1)2-1]1/2=(j-1)/2(1/y2+1/y)1/2 and j1/2-1 becomes (j-1)/2. I also made sure these two values ran together simultaneously. Substituting back into the formula, we now have a ratio for the forces of (v/c)/(1/y+1)1/2+1. Since y=(x/d)2, the total ratio of forces (for a moving body compared to a body at rest) at that instant where the body is at x travelling at a velocity v toward the perpendicular point for a continuous flow of force (the pulses have been eliminated) is (v/c)/(d2/x2+1)1/2+1. If the body is moving directly toward the other, then d=0 and the force would be (v/c)+1 times greater than if the two bodies were at rest.

    It turns out that the equation above reduces further to a ratio of forces of RF=1+(v/c)(cos a), where a is the angle between the line of motion and the position of the receiving particle from the previous position of the particle in motion (the velocities are calculated as if the receiving particle were at rest, or from its rest frame). If the particle in motion is travelling directly toward or away from the other, the forces are greater or less by 1+(v/c) and 1-(v/c), respectively. These can also be expressed as (c+v)/c and (c-v)/c, so the force acts as if it is travelling with the added velocity of the moving particle, even though this is not so. In the case of light itself, this would explain the results of the Michelson-Morley experiment. Light always appears to move with the additional frame of reference of the source, so it is measured the same in every case. Also, since cosine 90 degrees is 0, for a particle whose previous position is perpendicular to its line of travel in respect to the receiver, it is the same as if both particles are at rest to each other at this point.
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    I didn't read the post above mine - but yeah, gravity's influence travels at the speed of light.
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  8. #7 Re: Directional Gravity? 
    Forum Radioactive Isotope mitchellmckain's Avatar
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    Quote Originally Posted by icewendigo
    Is there any indication that gravity would be slightly shifted(doppler-like) in front and behind earth's path if earth was orbiting much faster than it is now(lets say 0.8 c), so that nearby in front of earth's path gravity would be slightly stronger initialy but diminish faster than usual as you get further out in front of earth's path, while behind earth gravity would be weaker than usual yet diminish with distance less than usual?
    A doppler-like shift would only apply to waves not forces, so if there are gravity waves then they would be affected by exactly the same doppler shift as light. Also please remember that motion is relative so whether the earth is moving or not (locally not the whole orbit) is a matter of perspective. Otherwise williams comment on frame dragging is right direction in which to look and is most commonly discussed in connection with Kerr (rotating) black holes (which suggests that the orbital speed must be extreme indeed for a measurable effect).

    Quote Originally Posted by icewendigo
    Forces
    The universe would make more sense to me if a force that is stonger than the strong force would act as a repulsive force on an even smaller scale, while a repulsive force even weaker than gravity acted on a much larger scale. Is there any indication that such extra-standard forces exist?
    The more complex (higher dimensional?) forces such as electro-magnetism, weak and strong nuclear forces can be repulsive of course. There are also theoretical states in which gravity or some unified force may be repulsive as discussed in the cosmological theory of inflation.

    Quote Originally Posted by icewendigo
    does gravity's effect travel at the speed of light?
    I don't think Hermes answered this completely satisfactorily, for the answer is absolutely YES, though grav was quite clear about this.



    Dear grav,

    A little more effort in making a clear statement of your conclusions would be greatly appreciated, not only for those who do not have the ability or inclination to wade through your mathematics, but even for those like me who have to decide whether they want to put in the time to do so. For even though I have considerable training and ability in this, it does not suffice to make it read like english and it takes a bit more work to grasp the message it contains. Even a group of professors attending a seminar would demand a bit more explanation, unless they are intimately involved in the project you are presenting.
    See my physics of spaceflight simulator at http://www.relspace.astahost.com

    I now have a blog too: http://astahost.blogspot.com/
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  9. #8 Directional gravity? 
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    Icewendigo wrote:
    Is there any indication that gravity would be slightly shifted(doppler-like) in front and behind earth's path if earth was orbiting much faster than it is now(lets say 0.8 c), so that nearby in front of earth's path gravity would be slightly stronger initialy but diminish faster than usual as you get further out in front of earth's path, while behind earth gravity would be weaker than usual yet diminish with distance less than usual?
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    The Special Theory allows for the contraction of physical matter in the direction of its motion at a rate proportional to its velocity. This seems to indicate two things: A. Physical matter is field energy. B. As field energy it doppler shifts accordingly. As the velocity of light is constant relative to the velocity of the coordinate system from whic it originates, so too does gravity.
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    Icewendigo wrote:
    Forces
    The universe would make more sense to me if a force that is stonger than the strong force would act as a repulsive force on an even smaller scale, while a repulsive force even weaker than gravity acted on a much larger scale. Is there any indication that such extra-standard forces exist?
    __________________

    An allotment very similar to that which you describe occurs in the 4th, 5th and 6th dimensions of gravity, electricity and magnetism respectively. Gravity as an alternatively vectored repelling force (Lambda - /\ ) has been issued since Einstein's Unified Field was published in 1919. It was abandoned eight years later but shows recent signs of returning to 'haunt' its rejecters. It appears that universal gravitation manifests in the micro and macrocosms as both an impelling and repelling force, without self contradiction.
    For more circumspect information on this issue you are referred to TOTAL UNIFIED FIELD THEORY (an anthological narrative authored by myself), at http://forums.delphiforums.com/EinsteinGroupie.
    Click on Part VII and that will access you to the entire menu.
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  10. #9  
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    Quote Originally Posted by icewendigo
    does gravity's effect travel at the speed of light?
    it is a force, it doesnt travel at all. but the effect would travel faster. it is not mass, or waves, so it would not be bound by the cosmic speed limit of C.
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  11. #10  
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    Quote Originally Posted by chamilton333
    Quote Originally Posted by icewendigo
    does gravity's effect travel at the speed of light?
    it is a force, it doesnt travel at all. but the effect would travel faster. it is not mass, or waves, so it would not be bound by the cosmic speed limit of C.
    Huh? Want to elaborate on this?
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