- #31
Yukterez
- 85
- 14
Did I mix that up? If so, I of course meant it the other way around (:Bandersnatch said:
Edit: I see, I was obviously too stupid to read my own chart (:
Are Galaxies Moving Faster Than Light Due to Space Expansion?
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SUMMARY
The discussion centers on the implications of Hubble's Law, particularly regarding galaxies moving faster than the speed of light due to the expansion of space. It is established that galaxies can recede from each other at velocities exceeding the speed of light, but this does not violate the local speed limit of light, as the expansion of space is the driving factor. The concept of an absolute frame of reference is dismissed, as all inertial frames behave identically, and measurements are relative to the Cosmic Microwave Background (CMB). The discussion also highlights that while local velocities are limited to the speed of light, recessional velocities have no upper limit.
PREREQUISITES- Understanding of Hubble's Law and its implications on cosmic expansion.
- Familiarity with the concept of the Cosmic Microwave Background (CMB).
- Knowledge of local versus recessional velocities in cosmology.
- Basic grasp of inertial frames of reference and their significance in physics.
- Explore the implications of Hubble's Law on cosmological models.
- Study the properties and significance of the Cosmic Microwave Background (CMB).
- Investigate the differences between local and recessional velocities in the context of general relativity.
- Learn about the concept of inertial frames and their role in modern physics.
Astronomers, astrophysicists, and students of cosmology who are interested in the dynamics of galaxies, the nature of space expansion, and the fundamental principles of relativity.
Edit: I see, I was obviously too stupid to read my own chart (:
- #32
Dale
Mentor
- 36,620
- 15,441
No. It isn't correct. The 5km/s value is simply relative to some arbitrary reference frame.user9003 said:
- #33
PeterDonis
Mentor
- 49,480
- 25,527
Bandersnatch said:
Ah, got it.
- #34
Yukterez
- 85
- 14
On the x-axis you have the redshift (as observed today), and on the y-axis the recessional velocity (orange is the velocity at emission and brown at absorption)
You see that objects with z < 1.8963 are faster today than they were when they emitted the light we receive now (the relative distance since then has changed more than the scale factor), while objects with z > 1.8963 are slower now than they were when they emitted their light (the expansion rate fell more than the distance increased while the light travelled).
You see that objects with z < 1.8963 are faster today than they were when they emitted the light we receive now (the relative distance since then has changed more than the scale factor), while objects with z > 1.8963 are slower now than they were when they emitted their light (the expansion rate fell more than the distance increased while the light travelled).
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