What do astronomers mean by the Big Bang?
A. the event that marked the beginning of the expansion of the universe
B. a gigantic explosion that blew all the galaxies in the universe to smithereens
C. the explosion of a massive star at the end of its life
D. the event that marked the birth of our solar system
Answer:A
What do astronomers mean by the Big Bang?
A. the event that marked the beginning of the expansion of the universe B. a gigantic explosion that blew all the galaxies in the universe to smithereens C. the explosion of a massive star at the end of its life D. the event that marked the birth of our solar system