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nameta9

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- Thread starter nameta9
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nameta9

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Galileo

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Likewise, if you take a laser pointer and you shine it at the moon, you can point from one side of the moon to the other with a flick of the wrist. The dot on the moon can travel faster than the speed of light. Here too, there's nothing violating relativity.

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CaptainQuaser

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Chronos

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Nonsense, not a single experimental result has been offered. Don't mean to be picky, but, what example of 'superluminal' velocity do you have in mind dgoodpasture2005? Perhaps you are thinking of phase velocity - a common misperception.

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- #5

lightgrav

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They are not called "superluminal" because in these cases the speed of the objects is still *less than the speed of light that we measure in a vacuum*. (At least this is true for the ones that we're responsible for, anyway, given momentum by ElectroMagnetic Fields).

IF you're willing to contemplate a theory for which "local gravity field" is well-defined, I think you have to admit that the speed of light in vacuum depends on the value of the local gravity field, being faster in weaker fields. FermiLab routinely makes protons travel faster than "the speed of light in interstellar space."

- #6

JesseM

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What do you mean by "local gravity field"? General relativity, the current best theory of gravity, says that a light beam will always be observed to travel at the same speed through a vacuum by observers in the same local region. And what's the basis for your claim that 'FermiLab routinely makes protons travel faster than "the speed of light in interstellar space"'? Do you have a link/reference for what you're talking about there?lightgrav said:IF you're willing to contemplate a theory for which "local gravity field" is well-defined, I think you have to admit that the speed of light in vacuum depends on the value of the local gravity field, being faster in weaker fields. FermiLab routinely makes protons travel faster than "the speed of light in interstellar space."

- #7

lightgrav

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This is really not the right thread, but you asked!

If you don't remember, a gravity field is the what *used* to cause

electrically neutral objects to change their momentum

when they were near another electrically neutral object.

Usually they were functions imposed upon flat space;

strong near large masses, and weaker farther away

(sort-of-like curvature). Having flat space meant that

if you made an equiangular triangle in space, and light

took a longer time to travel from angle A to angle B

than it took to travel from B to C (or C to A), those

watching would say that light went slower near the mass.

(They didn't know that the excess time should be interpreted

as a longer path distance with constant velocity.)

Sorry, what I thought I had written was:

... faster than "the speed that light seems to have,

through the strong fields near the Sun." In this interpretation,

the "universal speed limit" would be the faster speed of light

in the "weaker gravity field of interstellar space."

Somehow I lost a couple of lines.

- #8

IAN STINE

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What is the equation that defines change in speed versus strength of field? Thanks.

- #9

azneternity

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If anyone has this article please post it. I googled for it, and couldn't find it.

- #10

jim_990

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IAN STINE said:What is the equation that defines change in speed versus strength of field? Thanks.

f=ma perhaps

- #11

Phobos

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azneternity said:

If anyone has this article please post it. I googled for it, and couldn't find it.

Sounds like nonsense. But I'd be interested to see if anyone can find such a reference.

- #12

Ich

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Maybe you will find something when you google "Nimtz".azneternity said:

If anyone has this article please post it. I googled for it, and couldn't find it.

- #13

Jonny_trigonometry

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this local gravity idea has sparked my attention. I think I had this idea myself, and I was trying to explain it in a couple other threads. The fact that length (practically in all directions) and rate of time are both contracted in your 'local space' the closer you get towards a gravity source tells you that even though to you in that 'local space' measure the speed of light at c, someone else further away from the same gravity source in a 'local space' that isn't contracted as much will measure a different distance between points in your 'local space' which has a higher strength 'local gravity' and they would conclude that the speed of light in your referance frame is lower than the speed of light in their referance frame. But all that really matters is the strength of gravity in your local space, and the weaker the gravity strength, the less contracted space-time is, and the 'faster the speed of light' when measured from a frame with higher strength 'local gravity'. Although, in both stated referance frames (or 'local spaces'), the 'local' speed of light is the same. Therefore, light 'accelerates from high gravity potential to low gravity potential. does this make sense? I think you are able to extract the relation from GR.

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- #14

lightgrav

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require an unambiguous (not vague) scenario so that

the GR results can be interpreted in flat-space terms.

That's why both the transmitter "A" and receiver "B"

must be far from the star, in essentially flat space.

Only paths directly through the star are undeflected,

which is needed since the time-delay and deflection

will be effects of same order.

Anybody know how to do this convincingly?

(theory only, for now; experimentally next year (;->)

will still

- #15

Jonny_trigonometry

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I'm bettin it can be extracted from the energy density intrinsic in the curvature of space at any point r from the mass. Of course the unit of measure that you use to define volume should be unaffected by the mass, ideally at infinity. Then find a relation between energy density at r and length contraction of a meter stick brought from infinity to r (contraction measured by the meter stick at infinity). Is this a good way to approach the problem, that all measurement be compared to the length of a meter stick that isn't in a gravity field? It seems to me that we're going to need a universally constant unit of measure that sits outside the stretchability of space-time, which can be used in the knowledge of contraction factor caused by the local energy density of a gravity field to measure distances in that local space. za?

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