In the context of the FRW model (fig 5.23), which values or ranges of the parame
ID: 289121 • Letter: I
Question
In the context of the FRW model (fig 5.23), which values or ranges of the parameters k and correspond to universes with the following:
a) The universe is neither homogeneous nor isotropic.
b) There is no possibility of the big bang.
c) A big bang is possible, but there is at least one other possibility (assume > 0)
d) The particular point in space where the big bang happened can still be determined long after the event.
e) At any time, the large-scale geometrical properties of space are identical to those of a three-dimensional space with a flat geometry.
f) Space has a finite volume, and “straight’ lines that are initially parallel may eventually meet.
g) There is a big bang, but the volume of space is infinite from the earliest times.
(must answer for all letters.. not multiple choice)
Explanation / Answer
Ans) Friedmann, Robertson-Walker (FRW) models are established in cosmology. The value or ranges of
k = +1 (plus one) to -1 (minus one)
= 0 for homogeneous and isotropic.
a) ans- False, Universe is homogeneous and isotropic.
b) ans- False, There is possiblity of big bang as the universe has an encompassing space-time singularity at a finite time in the past.
c) ans- True
d) ans- True.
e) ans- True
f) ans- False, Parallel straight lines never meet.
g) ans- True, no longer could the universe be considered as infinite.