Video Transcript
Which of the following statements
is true? Is it (A) the universe is
contracting, (B) the universe is expanding, or (C) the universe is neither expanding
nor contracting?
We can answer the question by
recalling two facts. One, when the big bang occurred,
everything that exists in the universe now was in a volume of space smaller than an
atom. And two, the big bang occurred
billions of years ago.
It is obviously true that the
universe is now much, much larger than an atom. We see then that the universe must
have expanded since the big bang occurred. The big bang occurred billions of
years ago, and it has taken billions of years for the universe to become as it is
now. The universe has been changing
throughout the time between the big bang and now. The big bang was the start of the
expansion of the universe. This expansion of the universe has
continued since the big bang. And the universe is still expanding
today.
We see that option (B) is
correct. The universe is expanding.
