- #1
Damo ET
- 109
- 3
For the record, I completely accept the concept of an accelerating universe and the role dark energy plays (as the guys who figured these ideas out are light years beyond what I can hope to wrap my brain around). So, I am hoping someone can explain to me in layman terms why this the case.
Is it a case of an accelerating universe at this moment in time at all points in the universe?
or
Is it a case of an expanding universe in the past which we assume is still accelerating today based on what we see?
As we look at more and more distant galaxies back toward CMB, we are seeing greater and greater red shift due to the expansion of the 'space' between the photons being emitted, and our sensors. That's all well and good, but that was billions (upto 12 billion+) years ago when the universe was far younger and smaller. Even if the expansion of the universe was slowing, the further we look back, the faster it would appear to receding!
One way which I could figure we could assume that expansion is accelerating would be to know the redshift to a galaxy, and actually see an increase in that redshift over time. But this is obviously not the way it is done.
Or is there a halo in all directions at a certain distance/time where there is a change in the characteristics of what we see, which indicates an accelerating universe?
I can't help but think I am missing something very fundamental. Any help would be appreciated.
Damo
Is it a case of an accelerating universe at this moment in time at all points in the universe?
or
Is it a case of an expanding universe in the past which we assume is still accelerating today based on what we see?
As we look at more and more distant galaxies back toward CMB, we are seeing greater and greater red shift due to the expansion of the 'space' between the photons being emitted, and our sensors. That's all well and good, but that was billions (upto 12 billion+) years ago when the universe was far younger and smaller. Even if the expansion of the universe was slowing, the further we look back, the faster it would appear to receding!
One way which I could figure we could assume that expansion is accelerating would be to know the redshift to a galaxy, and actually see an increase in that redshift over time. But this is obviously not the way it is done.
Or is there a halo in all directions at a certain distance/time where there is a change in the characteristics of what we see, which indicates an accelerating universe?
I can't help but think I am missing something very fundamental. Any help would be appreciated.
Damo