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David Lewis
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- Could the frequency of cosmic background radiation blue-shift?
If a spaceship travels near the speed of light, could the frequency of cosmic background radiation blue-shift?
Does this mean we're not either?PAllen said:It is also how we know that the sun is not a comoving body. We see anisotropy of the CMB. Modeling earth’s motion around the sun, we know that the sun would not see CMB isotropy. Nor would the milky way galaxy as a whole. Nor would the local group of galaxies.
Of course. I thought that was too obvious to state, e.g. if the milky way was comoving, the Earth could not be. Actually I said we, on earth, see anisotropy. That, by definition, means we are not comoving.Grasshopper said:Does this mean we're not either?
Yes.Grasshopper said:Does this mean we're not either?
Google said:about 627 km/sec
PAllen said:Of course. I thought that was too obvious to state, e.g. if the milky way was comoving, the Earth could not be. Actually I said we, on earth, see anisotropy. That, by definition, means we are not comoving.
[post originally said isotropy instead of anisotropy]
Good. Because that would be an insane coincidence.jbriggs444 said:Yes.
One can Google (one moment while I do). "speed of Earth relative to cmb" and get an answer ofEdit: One can also Google for "speed of Earth relative to sun in km/s" and see that our velocity with respect to the sun is only about 30 km/sec. So no, we can't just wait six months and wind up momentarily at rest relative to the CMBR. Our velocity relative to the Milky Way is only about 220 km/sec. So we can't wait for half of a galactic year (100 million years or so) and expect that to work either.
"Preferred" in the sense of being picked out by a particular symmetry in the distribution of stress-energy, yes.David Lewis said:If the wavelength of background microwave radiation is the same in all directions, does that imply a preferred frame of reference?
Like the local rest frame of the surface of the Earth is a preferred frame for Earthbound physics, yes. The formulae are the same in any frame, but terms often simplify or drop out in the frame where most of the mass is at rest.David Lewis said:If the wavelength of background microwave radiation is the same in all directions, does that imply a preferred frame of reference?
Light speed traveling is the concept of traveling at the speed of light, which is approximately 299,792,458 meters per second. It is the fastest known speed in the universe and is often used in science fiction as a means of interstellar travel.
Light speed traveling has a minimal effect on cosmic background radiation. This is because the cosmic background radiation is already spread out evenly throughout the universe and does not change significantly with the movement of objects.
Yes, according to Einstein's theory of relativity, as an object approaches the speed of light, time for that object will appear to slow down for an outside observer. This is known as time dilation and is a well-documented effect of light speed traveling.
Currently, it is not possible for humans to travel at the speed of light. The amount of energy required to reach this speed is immense and would require technology far beyond our current capabilities. However, scientists continue to explore and research ways to potentially achieve light speed travel in the future.
One of the main concerns for human light speed travel is the potential health effects on the body. The extreme speeds and acceleration involved could cause physical strain and potential damage to the body's cells and organs. Further research is needed to fully understand and mitigate these potential effects.