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Drakkith
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So I was thinking...if an object is moving THROUGH space, as opposed to WITH space, then wouldn't the CMB be noticeably anisotropic?
Drakkith said:So I was thinking...if an object is moving THROUGH space, as opposed to WITH space, then wouldn't the CMB be noticeably anisotropic?
Drakkith said:So I was thinking...if an object is moving THROUGH space, as opposed to WITH space, then wouldn't the CMB be noticeably anisotropic?
Others have provided good answers here, but I thought I'd add in a little caveat.Drakkith said:So I was thinking...if an object is moving THROUGH space, as opposed to WITH space, then wouldn't the CMB be noticeably anisotropic?
Chalnoth said:Others have provided good answers here, but I thought I'd add in a little caveat.
There is no absolute distinction between moving "through" or "with" space. Space itself has no absolute motion. The CMB rest frame is only a convenient choice of rest frame when doing cosmology. It is not an absolute frame.
Interestingly, the movement of galaxy clusters with respect to the CMB changes how the cloud of hot gas within those clusters interacts with the CMB. So we can, in principle, measure the movement of these galaxies with respect to the CMB simply by examining their brightness. In practice this is fantastically difficult because it turns out that the spectrum of this deviation in brightness is exactly the spectrum of the CMB itself, so I'm not sure that we've ever had a confirmed example of the kinetic SZ effect (that's the name of this effect).
Ahh, interesting. Here is the source paper, in case anybody is interested:RUTA said:
Chalnoth said:There is no absolute distinction between moving "through" or "with" space. Space itself has no absolute motion.
Doesn't work. No galaxy moves faster than a light ray moving past it. Nothing can.Krunchyman said:The fact that galaxies move faster than the speed of light is the reason why we could potentially use hypothetical Alcubierre drives to accelerate objects faster than light speed.
Krunchyman said:The fact that galaxies move faster than the speed of light is the reason why we could potentially use hypothetical Alcubierre drives to accelerate objects faster than light speed.
The speed of light is a fundamental constant in physics, denoted by the letter "c". It is approximately 299,792,458 meters per second in a vacuum.
According to the theory of relativity, nothing can travel faster than the speed of light. This is a fundamental principle in physics and has been supported by numerous experiments and observations.
The speed of galaxies can be measured using the Doppler effect, which is the change in frequency or wavelength of a wave due to the relative motion between the source and observer. By measuring the redshift or blueshift of light emitted from galaxies, we can determine their speed and direction of motion.
No, galaxies are not moving faster than the speed of light. The expansion of the universe is causing the space between galaxies to stretch, which can make it appear as though they are moving faster than the speed of light. However, this does not violate the principle that nothing can travel faster than the speed of light.
The fact that galaxies appear to be moving away from each other at speeds faster than the speed of light suggests that the expansion of the universe is accelerating. This has implications for the future of the universe, as it may continue to expand indefinitely and eventually lead to a "heat death" where all matter and energy are evenly distributed and no longer able to sustain life.