Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Novaflipps on 07/12/2016 20:02:10
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Does not that explain the redshift effect we see when we see so far. Is not the doppler effect, not according to Einsteins relativity?
A not expanding universe
Will not photons over large distances loose abit of energy because of the universial gravitational potensial? The work, preformed by the light to overcome the gravity over so waste distances, so the frequenzy drops down to red, theras redshift effect?
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It all has to do with energy and reference frame, which are related. The gravitational red shift is based upon the different way that time passes near a gravitating body compared to further away from it. (There is also a redshift based on velocity, having to do with the difference in space between it and the observer at different times [doppler shift], and the different passage of time by its clock compared to that of the observer [time dilation]. So actually, we have three phenomena happening that affect the red shift. The cosmological red shift that is associated with the general distance of a body from Earth, and that the further away it is in cosmological terms, the stronger the red shift --- that phenomenon is, I understand, mainly related to the speed with which the body is moving away from Earth, which is in general proportional to its distance from Earth. This has been called the expanding universe. I do not entirely understand the expanding universe, but it would seem that the red shift arising from it is functionally equivalent to the Doppler shift associated with an emitter that moves rapidly away from the observer.
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By the way, all this does indeed involve energy, because energy is affected by reference frame and motion. Photons from a receding body will arrive at the (local) speed of light, but are de-energized from what they were when they departed because they are not in the original reference frame when being observed. However, as viewed in the original reference frame, they will still have their original energy, so long as the case is simple and can be described by Special Relativity without having to consider gravitational effects.
In the case of red shifts caused by gravity, such as from the surfaces of nearby but massive stars, energy and reference frame are still involved, but somewhat differently. Because of the gravity, the clock located near the star's surface runs slower than that of the observer, and the photon that is emitted is synchronized to it, so arrives at the observer with a lower frequency and lesser energy than would have been seen by an observer at the surface. To describe this as the photon "losing energy as it climbs out of the gravitational well" is actually correct, and is a different way of saying the same thing, because at the quantum level, energy and frequency are proportional, so that any time a particle moves from one gravitational potential to another, it is changing both its energy and its frequency -- the two phenomena go hand-in-hand, and are an inevitable consequence of the space-time relationships.
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The further we see, the more redshift effect we get right? And the photons that reaches the earth will have lesser energy. So it could mean that the so-called doppler effect don't actually explain the acceleration of the expansion. Rather that it may expand, but not faster and faster
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And another thing. We can see about 13 billion lightyears no matter wich direction . Would that not then be the radius of the universe? And the universe is then stretching over 26 billion light years? And because we can't see any further, how can we then estimate the age? Let's say in 10 years we can see even further. Then the age will increase? So we actually don't have a clue about the age. It's just the observers point if view.