The unitless value z is what denotes redshift.
At z=1, we are half way to the beginning of time.
At z=infinity, we are at the beginning of time.
It's 1/(z+1).
So at z=2 we see the universe at 1/3 its current age. z=9 is 1/10th.
The CMB is at z=1100.
The difference between z=0 and z=1 is 7 billion years.
The difference between z=9 and z=1100 is 1.3 billion years.
A lot depends on this being right.
What if it isn't?
At z=1, we are half way to the beginning of time.
At z=infinity, we are at the beginning of time.
It's 1/(z+1).
So at z=2 we see the universe at 1/3 its current age. z=9 is 1/10th.
The CMB is at z=1100.
The difference between z=0 and z=1 is 7 billion years.
The difference between z=9 and z=1100 is 1.3 billion years.
A lot depends on this being right.
What if it isn't?
via International Skeptics Forum https://ift.tt/tER96c3
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