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Austrian physicists Josef Lense and Hans Thirring … predicted that the rotation of a massive object would distort spacetime metric, making the orbit of a nearby test particle precess. This does not happen in Newtonian mechanics for which the gravitational field of a body depends only on its mass, not on its rotation. The Lense-Thirring effect is very small—about one part in a few trillion. To detect it, it is necessary to examine a very massive object, or build an instrument that is very sensitive. Linear frame dragging is the similarly inevitable result of the general principle of relativity, applied to linear momentum. Although it arguably has equal theoretical legitimacy to the "rotational" effect, the difficulty of obtaining an experimental verification of the effect means that it receives much less discussion and is often omitted from articles on frame-dragging
I personally don't think it would make any difference to speed c. (Although with absorption and re-emission it may appear to). The way I see it is light travels instantaneously in its own reference frame (please excuse my use of inadequate language). In other words it travels at infinite speed and that infinite speed cannot be added to or subtracted from.
Looks like an experiment to measure "linear frame dragging" …
This also means that light traveling in the direction of rotation of the object will move past the massive object faster than light moving against the rotation, as seen by a distant observer.
Quote from: MikeS on 10/01/2012 07:39:07I personally don't think it would make any difference to speed c. (Although with absorption and re-emission it may appear to). The way I see it is light travels instantaneously in its own reference frame (please excuse my use of inadequate language). In other words it travels at infinite speed and that infinite speed cannot be added to or subtracted from.Except, it isn't quite an infinite speed. It has been measured to be 299,792,458 metres per second in a vacuum.The speed varies based on the medium, so it is slower in water than in air. Varying speed in different mediums is more complicated than absorption/re-emission, as I believe the spectrum isn't changed, except for light that is actually absorbed. In this case, though, I am proposing to shine the light through a gap between two moving objects, done in a vacuum, hopefully avoiding interference with the medium.If the observer is moving, then it can be red-shifted, or blue shifted depending on the direction of the observer, but the speed measurement is the apparently the same. We are also seeing this red-shifting and blue-shifting with the distance and direction of movement of stars.Anyway, my thought is to essentially have a fixed emitter, fixed observer, but move the "space" between the two.
According to General Relativity... Both speed detectors would measure the speed of light in their spinning disk frame at precisely the "speed of light", C, despite each detector going in the opposite direction at a rapid rate. There would be some red-shifting or blue-shifting of the wavelength in the spinning disk frame.So, wouldn't you have to conclude that the light has either slowed down, or sped up in the overall frame.
Back to the original experiment, one option to enforce the "frame" would be to use a glass disk, but that would induce a host of problems, so, I chose to suggest using a vacuum, with a narrow, empty gap between the disks.
Surely you don't have to measure the speed of light with a roundtrip back to the source.I believe one method to get an actual measurement of the speed of light is to have it pass through a series of shutters. Then, calculate the delay between the opening and closing of the shutters, when the light actually passed through.
http://en.wikipedia.org/wiki/One-way_speed_of_light#Experiments_that_can_be_done_on_the_one-way_speed_of_light
...the length of time you spend moving the clock will also fall increasingly more with speed rather than in proportion to speed because the distance you're taking the clock will contract at higher speeds at exactly the rate required to ensure that no matter what speed you move the clock at you will end up with the same overall slowing (or speeding up) of that clock.
So, when we say the speed of light is invariant, it is only in reference to a two-way measurement.
One possible frame of reference would be the Cosmic Microwave Background Radiation.
It should be easy enough to do a one-way light experiment in space.
Say you put 2 satellites in geosynchronous orbit, at an elevation of about 42,000 km. Two satellites on opposite sides of the globe would be about 84,0000 km apart.The speed of light is about 300,000 km/sec.So, your two geosynchronous satellites are about 0.28 light seconds apart.
One trick might be to synchronize the clocks without respect to the CMBR, and the one-way speed of light. But, this could be done by synchronizing them with respect to a solar eclipse. You would still have the half degree progression of the solar orbit in a half a day.... but should be able to throw that into one's calculations.
Synchronize their clocks with a known eclipse (Jupiter eclipse, or to one's favorite star whatever), and run satellite to satellite communication pulses.