View Single Post
  #15  
Old 23-05-2010, 09:19 PM
mjc's Avatar
mjc (Mark)
Registered User

mjc is offline
 
Join Date: Mar 2010
Location: Dublin, Ireland
Posts: 52
Quote:
Originally Posted by sjastro View Post
The Lorentz transformation won't work as it only applicable if the recession velocity is constant.

The recessional velocity for an expanding metric increases as the distance between the observer and object increases.

Regards

Steven
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
Reply With Quote