Quote:
Originally Posted by mjc
Are you sure lorentz transformations do not apply here. I understand your line of thought in being careful to preclude special relativity where there is acceleration and/or gravity involved. However, the recessional velocities due to the expansion of the universe is not due to motion through space (there's no inertia - stop space expanding and one would not expect the bodies to keep moving - also superluminal velocities are not forbidden). The recessional velocities are a result of distant galaxies comoving with space.
I just found this
http://www.mso.anu.edu.au/~charley/papers/DavisLineweaver04.pdf
(Do a search on "expanding confusion" and you'll find more material.)
Which looks pertinant - I've read material by both Davis and Lineweaver before on this subject area and its always been rewarding. I Can't recall if I've read this particular paper before but it covers the same ground.
Just my two cents (they're Euro cents so thats even less now...)
Mark |
Hello Mark,
The point I was making is that a SR Lorentz transformation cannot be used for a comoving coordinate system. For a Lorentz transformation to be applicable, one would need to convert the comoving system into the observer's local coordinates.
To do this the distance between the observer and object needs to be broken into small intervals, such that each interval is small enough for metric expansion to be negligible in each interval.
Then apply the Lorentz tranformation to each interval, and sum the time dilation for each interval.
Therefore in a metrically expanding Universe the Lorentz tranformation is multlplied by a scale factor.
Experimentally it is impossible to measure the time dilation using this method as one would require "clocks" in each interval.
Regards
Steven