Where Does the Lost Energy Go in Cosmological Redshift?

In summary, this is my first time on physics forums, and I am glad to have the chance to participate. My questions have been asked many times by others, but after lots of research, including among these threads on physics forums, especially “hurk4” on Feb 14-07 and Will Kastens, I can find no definitive answers.
  • #1
Bobbywhy
Gold Member
1,733
52
This is my first time on physics forums, and I am glad to have the chance to participate. My questions have been asked many times by others, but after lots of research, including among these threads on physics forums, especially “hurk4” on Feb 14-07 and Will Kastens, I can find no definitive answers.

Einstein wrote (The Principle of Relativity”, Dover, 1952, p.71): “…radiation conveys inertia between the emitting and the absorbing bodies.” Each photon subject to the cosmological redshift apparently conveys less energy to the absorber than it had when it was emitted.
Question. # 1. Since energy is always conserved, where has this difference in energy gone?

The following references are relevant:
Misner, Thorne, Wheeler (Gravitation, section 29.2): “A detailed analysis focuses attention on three processes: emission, propagation, and absorption. Emission and absorption occur in the proper reference frames (orthonormnal tetrads) of the emitter and receiver; they are special-relativistic phenomena. Propagation, by contrast, is a general-relativistic process: it is governed by the law of geodesic motion in curved spacetime.”

Sten Odenwald and Rick Fienberg (“Sky and Telescope”, February 1993, “Galaxy Redshifts Reconsidered): “Steven Weinberg and Jaylant Narlikar and John Wheeler, “The frequency of light is also affected by the gravitational field of the universe, and it is neither useful nor strictly correct to interpret the frequency shifts of light...in terms of the special relativistic Doppler effect.” In fact, general relativity allows the Conservation of Energy to be suspended so that matter and energy may be created quite literally from the nothingness of curved spacetime.”

Peebles (Principles of Physical Cosmology, 1995, p. 139): “Where does the lost energy go? ... The resolution of this apparent paradox is that while energy conservation is a good local concept ... and can be defined more generally in the special case of an isolated system in asymptotically flat space; there is not a general global energy conservation law in general relativity theory.”

Whereas Einstein wrote (The Principle of Relativity”, Dover, 1952, p. 150): “Thus it results from our field equations of gravitation that the laws of conservation of momentum and energy are satisfied.”

Questions # 2. The object which emitted Gamma Ray Burst 080913 was measured to be at a redshift of 6.7, or at a distance of 12.8 Billion light-years. Since all e-m radiation is subject to the cosmological redshift, and the Swift satellite detector received gamma rays, how much energy did that radiation have when it was emitted? Do we need a new name for it?
 
Astronomy news on Phys.org
  • #2
1. The key word you are missing in that Einstein quote is "apparently". Kinetic energy and momentum are frame of reference dependent (in both Einstein's and Galileo's relativity), so they can be different in one frame than another. There is no violation of COE.

2(b). Gamma rays are anything above 10^19 hz, so no, there wouldn't ever be a need for another name for a band above them.
 
  • #3
Those are great quotes!
Bobbywhy said:
The following references are relevant:
Misner, Thorne, Wheeler (Gravitation, section 29.2): “A detailed analysis focuses attention on three processes: emission, propagation, and absorption. Emission and absorption occur in the proper reference frames (orthonormnal tetrads) of the emitter and receiver; they are special-relativistic phenomena. Propagation, by contrast, is a general-relativistic process: it is governed by the law of geodesic motion in curved spacetime.”

Sten Odenwald and Rick Fienberg (“Sky and Telescope”, February 1993, “Galaxy Redshifts Reconsidered): “...Steven Weinberg and Jaylant Narlikar and John Wheeler, 'The frequency of light is also affected by the gravitational field of the universe, and it is neither useful nor strictly correct to interpret the frequency shifts of light...in terms of the special relativistic Doppler effect.' In fact, general relativity allows the Conservation of Energy to be suspended so that matter and energy may be created quite literally from the nothingness of curved spacetime.”

Peebles (Principles of Physical Cosmology, 1995, p. 139): “Where does the lost energy go? ... The resolution of this apparent paradox is that while energy conservation is a good local concept ... and can be defined more generally in the special case of an isolated system in asymptotically flat space; there is not a general global energy conservation law in general relativity theory.”

I put the nested quotation from Weinberg et al in italics to help distinguish the two levels. Hope I got it right. The main message, that GR allows COE to be suspended, is I think in Odenwald Fienberg's words.

BTW welcome to Physicsforums!
 

Related to Where Does the Lost Energy Go in Cosmological Redshift?

What is redshift energy conservation?

Redshift energy conservation is a principle in physics that states the total energy of a system remains constant as its wavelength increases due to the Doppler effect. This phenomenon is observed in the universe when light from distant objects appears redder than expected, indicating that they are moving away from us.

How is redshift energy conservation related to the expansion of the universe?

The redshift observed in the light from distant galaxies is due to the expansion of the universe. As the universe expands, the wavelength of light from these galaxies stretches, causing the light to appear redder. This is consistent with the principle of energy conservation, as the total energy of the light remains constant even as its wavelength changes.

What is the difference between redshift and blueshift?

Redshift and blueshift are two opposite effects of the Doppler effect. Redshift occurs when an object is moving away from the observer, causing the wavelength of light to stretch and appear redder. Blueshift, on the other hand, occurs when an object is moving towards the observer, causing the wavelength of light to compress and appear bluer.

How is redshift energy conservation used in cosmology?

In cosmology, redshift energy conservation is used to study the expansion of the universe and the distance of galaxies. By measuring the redshift of light from distant objects, scientists can determine the velocity at which these objects are moving away from us and calculate the rate of expansion of the universe.

Can redshift energy conservation be violated?

No, redshift energy conservation is a fundamental principle in physics and has been extensively tested and confirmed through various experiments and observations. However, there may be some rare cases where apparent violations of this principle occur due to other factors such as gravitational lensing or peculiar velocities of galaxies.

Similar threads

Replies
4
Views
533
Replies
5
Views
2K
Replies
13
Views
1K
Replies
12
Views
879
Replies
1
Views
1K
Replies
22
Views
1K
Back
Top