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Loren Booda
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If not Doppler, what type of transformation does Hubble's law utilize?
Loren Booda said:If not Doppler, what type of transformation does Hubble's law utilize?
Hi marcus, the funny thing is that Maxwell's Equations is only math and not physics. Similarly as Newton's Equations in gravitation. As the "attractive forces" are only mathematical models of the "real stuff" (the curvature of spacetime) in physics of gravitation, the "waves" are only mathematical models in EM, and not very reliable neither. That's we we rely rather on "photons" and their redshift telling us something about sapace and time. E.g. why would we assume that space expands rather that it is not time running slower in deep space due to the amount of matter between us and those galaxies (as was once Einstein's idea)?marcus said:One way to think about it is via Maxwell's Equations. They are geometrical and govern wave propagation. In an environment where distances are not increasing they guarantee that the most recent undulation (at the advancing wavefront) will have the same wavelength as the one preceding it. [...]
Loren Booda said:A quote from Cosmology by Michael Rowan-Robinson, 3rd edition, page 65:
"...we have a natural explanation of the Hubble law, with the cosmological redshift being interpreted as a Doppler shift."
Hubble's law is based on the observation that galaxies are moving away from each other, and the rate at which they are moving is directly proportional to their distance. This is known as the cosmological redshift, which is caused by the Doppler shift. As galaxies move away from each other, the light they emit is stretched to longer, redder wavelengths, resulting in a redshift.
The Doppler shift is important in Hubble's law because it provides evidence for the expansion of the universe. By measuring the redshift of light from distant galaxies, scientists can calculate their recessional velocity and use this to determine the distance to the galaxy. This allows for the estimation of the Hubble constant, which is a key parameter in understanding the rate of expansion of the universe.
No, Hubble's law also takes into account the effects of the expansion of the universe. This is known as the cosmological redshift, which is due to the stretching of space itself as the universe expands. This redshift is not caused by the Doppler shift, but rather by the expansion of the space between galaxies.
The Doppler shift is an important tool in our understanding of the universe as it allows us to measure the distances and velocities of galaxies. This, in turn, helps us to understand the expansion of the universe, the size and age of the universe, and the distribution of matter within it. The Doppler shift also plays a crucial role in the study of other cosmic phenomena such as the motion of stars within galaxies and the behavior of objects in binary systems.
Yes, Hubble's law can also be applied to other celestial objects beyond galaxies, such as quasars and clusters of galaxies. By measuring the redshift of light from these objects, scientists can determine their distance and velocity, providing valuable insights into the structure and evolution of the universe. This has also allowed for the discovery of extremely distant and ancient objects, providing a glimpse into the early stages of the universe.