- #1
Rodney-Believes
- 19
- 0
I read in Wikipedia that
"For supernovae at redshift less than around 0.1, or light travel time less than 10 percent of the age of the universe, this gives a nearly linear distance–redshift relation due to Hubble's law. At larger distances, since the expansion rate of the universe has changed over time, the distance-redshift relation deviates from linearity, and this deviation depends on how the expansion rate has changed over time."
If the expansion of space is stretching the light traveling through it (creating the red-shift), and acceleration began about 5 billion years ago, then why is the most recently emitted light "nearly linear distance-redshift relation"? It would seem that within expansion, which is red-shifting the light, acceleration began recently, then the newer light would red-shifted under an acceleration, so why is it more linear? The "older" light, which would have traversed the universe through both steady rate (or decelerating) and accelerating. It should be closer to linear depending on how very distant, how much more of the red-shift came from steady-rate vs accelerating.
In other words, if in observation the newer light is "nearly linear" and the older light is not, and it is the expansion that is shifting the frequency of the light, that would suggest to me that the universe was once accelerating but has become more steady rate in recent times. Can someone set me straight on this?
Thank you.
"For supernovae at redshift less than around 0.1, or light travel time less than 10 percent of the age of the universe, this gives a nearly linear distance–redshift relation due to Hubble's law. At larger distances, since the expansion rate of the universe has changed over time, the distance-redshift relation deviates from linearity, and this deviation depends on how the expansion rate has changed over time."
If the expansion of space is stretching the light traveling through it (creating the red-shift), and acceleration began about 5 billion years ago, then why is the most recently emitted light "nearly linear distance-redshift relation"? It would seem that within expansion, which is red-shifting the light, acceleration began recently, then the newer light would red-shifted under an acceleration, so why is it more linear? The "older" light, which would have traversed the universe through both steady rate (or decelerating) and accelerating. It should be closer to linear depending on how very distant, how much more of the red-shift came from steady-rate vs accelerating.
In other words, if in observation the newer light is "nearly linear" and the older light is not, and it is the expansion that is shifting the frequency of the light, that would suggest to me that the universe was once accelerating but has become more steady rate in recent times. Can someone set me straight on this?
Thank you.