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seen Apr 25 at 20:33

Apr
21
awarded  Popular Question
Apr
17
revised Light clocks measure conformal time - detailed argument
added 364 characters in body
Apr
16
comment Light clocks measure conformal time - detailed argument
Ok - I see what i've done wrong now!
Apr
16
accepted Light clocks measure conformal time - detailed argument
Apr
15
revised Light clocks measure conformal time - detailed argument
added 52 characters in body
Apr
15
revised Light clocks measure conformal time - detailed argument
added 15 characters in body
Apr
15
revised Light clocks measure conformal time - detailed argument
added 628 characters in body
Apr
15
comment Light clocks measure conformal time - detailed argument
Instead of introducing $\rho$ maybe I should have just introduced $r(\tau)=r(t)dt/d\tau$. If the end of the light clock travels on the path $r(t)=1/a(t)$ then that is also $r(\tau)=(1/a)*a=1$.
Apr
15
revised Light clocks measure conformal time - detailed argument
deleted 4 characters in body
Apr
15
asked Light clocks measure conformal time - detailed argument
Apr
13
asked Is our locally measured time actually conformal time?
Apr
11
comment Does time expand along with space?
@AlfredCentauri If one takes $dr=0$ then one just finds that proper time for a co-moving observer is the same as cosmological time. But a co-moving observer would be expanding with the Universe whereas we do not. He would be measuring time with an expanding light clock whereas our light clocks have a fixed length.
Apr
11
comment Does time expand along with space?
I'm arguing that intervals of cosmological time $c\ dt=a(t)dr$ expand in exactly the same way as intervals of space $ds=a(t)dr$.
Apr
10
asked Does time expand along with space?
Apr
8
comment Are atomic energies increasing as the Universe expands?
I would have thought that one can apply the FRW metric at all scales - provided masses are small. Imagine a hydrogen atom sitting alone in space. I don't assume that it expands. In fact I explicitly state that it maintains a constant proper size.
Apr
8
asked Are atomic energies increasing as the Universe expands?
Mar
27
revised Redshift of supernova light curve
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Mar
26
comment Redshift of supernova light curve
So is it true to say that cosmological redshift is completely equivalent to time dilation? Could one consistently assert that an atomic clock ticking millions of years ago is actually slower than the equivalent clock today?
Mar
26
accepted Redshift of supernova light curve
Mar
26
comment Redshift of supernova light curve
I'm just using a Gaussian as an example to understand how the width of a light pulse changes due to redshift.