4. [4pt]
Choose the correct statements from the following list referring thepossible futures of a Universe that does NOT contain Dark Energy.(Give ALL correct answers, i.e., B, AC, BCD...)
A) At present the visible matter in the Universe is only about 1percent of the mass needed to reach the critical density.
B) The critical density is equivalent to only six atoms of hydrogenin a volume the size of a typical closet (about one cubicmeter).
C) If the density of the Universe is found to be greater than thecritical density, the big bang theory must be incorrect.
D) The critical density is the density needed to cause the BigBang.
E) Probably the ultimate fate of the Universe will be to collapseinto a series of large black-holes.
F) If the density of the Universe is less than the critical densitythe Universe will eventually collapse into a big crunch.
G) It is possible the Universe has undergone a series of big bangs,expansions and contractions.
