Horizon and the question whether galaxies that recede faster than light are observable

Details Horizon and the question whether galaxies that recede faster than light are observable Horizon and the question whether galaxies that recede faster than light are observable

Feb 1997

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997cha%26a..21....1k&link_type=abstract

Chinese Astronomy and Astrophysics, Volume 21, Issue 1, p. 1-18.

Astronomy and Astrophysics

Astrophysics

5

Scientific paper

To the question, ``Can we observe galaxies that recede faster than light?'', the great majority of cosmologists at present would answer, ``No, such galaxies are outside our horizon''. Underlying this answer is the idea that velocity in relativistic cosmology has to be defined by the relativistic Doppler shift formula. But in cosmology, redshift is ``cosmological'' and not ``Doppler''. And thereis available an independent definition of velocity. Thanks to the Cosmological Principle, there is a distance-independent, universal time t and a time-dependent, instantaneous distance l, and velocity can naturally be defined as dl/dt. With this definition and the cosmological interpretation of redshift, it is shown: (1) That ``horizon'', which owes its role as the limit of observation to its association with infinite redshift, is irrelevant to the question. (2) That the answer must depend on the particular cosmological model. Specifically, the answer is NO for the steady state model, and YES for all three types (k = 0, -1, +1) of the big bang model; in the k = 0 model, all sources with redshifts greater than 1.25 would have had their recession velocities at the time of emission greater than 1 light velocity. It has been found useful to contrast the character of time and distance in cosmology and black hole physics. A brief history of time, distance, velocity and redshift is given to show that the Doppler formula is inapplicable to recession velocities. Based on the present approach, a ``World Atlas of the Universe'' is constructed, which shows, inter alia, that recession and photon velocities at distant points obey the old, pre-relativity law of addition, while the local speed of light is kept constant

Affiliated with

Also associated with

No associations

Rating

Horizon and the question whether galaxies that recede faster than light are observable does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Horizon and the question whether galaxies that recede faster than light are observable, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Horizon and the question whether galaxies that recede faster than light are observable will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1775971