8/14/2023 0 Comments Red shift internetIt is all a matter of reference frames, imo. As far as measurements go I do not see why it would not hold, that the atom moving away from us and the photon arriving in our detectors have to balance the energy, after all each photon signals a single interaction. My argument above relates to reference frames and does not discuss expansion of space itself as in cosmological models. This is normally interpreted as a direct, physical observation of the expansion of the spatial volume of the observable universe. Hubble's law is the name for the observation in physical cosmology that: (1) objects observed in deep space (extragalactic space, ~10 megaparsecs or more) are found to have a Doppler shift interpretable as relative velocity away from the Earth and (2) that this Doppler-shift-measured velocity, of various galaxies receding from the Earth, is approximately proportional to their distance from the Earth for galaxies up to a few hundred megaparsecs away. These redshift observations led to Hubbles law, For an observer at rest on the ground the two bullets will have different energies even though the gun shoots with the same energy at the rest frame of the train. It is similar to shooting from a moving train: if ahead the bullet will gain energy from the train, if behind, the train will gain energy from the bullet and the bullet will be slower. In relativistic speeds one should use the special relativity equations.That is how we find that the galaxy is moving after all! We see the photon with less energy and if we could measure the deexcited atom we would see it balance the energy. The next line from the bottom is a nearby galaxy, this galaxy is moving, and so the rest system of the atom is moving with respect to us. We observe it as at the star level on the left of the image. In the center of mass system of the excited atom ("deexcited-atom and photon" )the spectral line is fixed if our rest frame coincides with the rest frame of the atom. This means we are dealing with special relativity equations. Let us take a simple redshift of a spectral line from a moving galaxy. But the Robertson-Walker metric doesn't admit such a vector field. Very often in the definition of energy you need a time-like Killing vector field to have a constant energy. You can find from the geodesic equation (using the Robertson-Walker metric) that the velocity is inverse proportional to the cosmic scale factor, so decrease with time.įrom another point of view, you can say that is the time dependence of the metric that breaks conservation of energy.Īt the end it really depends on the definition of energy you want to use. If the four velocity is time dependent, like in an expanding universe, the energy is not a conserved quantity. That is constant, and the energy is conserved. \mathcal =(1,0,0,0) $ in Minkowski space-time, we have: We also offer in-house website design and hosting, domain registration, email hosting, and co-location services. For a particle with four-momentum $ P^\mu $, measured by an observer with four velocity $ u^\mu $, is defined as: Red Shift offers high speed Internet service via DSL, wireless, T1, DS3, satellite, and dialup connections. The energy of a particle is an observer-dependent quantity in General Relativity.
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