Formation of the Universe
One of the most difficult questions to answer in man-kind is probably this one, "How did the universe begin?" There are multiple theories for this particular question, but The Big Bang, is the most widely accepted of them all. According to this theory, the universe began expanding from am extremely small size with a high density and temperature. The Big Bang is not an explosion in empty space, but rather that space itself began with the Big Bang and carried matter with it as it expanded. Physicists also think time began with the Big Bang.
The evidence for this theory is so overwhelming almost every scientist agrees. One observation over the past century led astronomers become certain that the universe started with the Big Bang. Their first observation was that the universe is expanding which led scientists to believe everything was super close together before some sort of explosion. Secondly, the Big Bang perfectly explains the abundance of helium and other nuclei. Only a hot, dense, and expanding environment could create the abundance of nuclei we observe today. Lastly, astronomers can actually obverse the cosmic background radiation (the afterglow of the explosion) from every direction in the universe.
The evidence for this theory is so overwhelming almost every scientist agrees. One observation over the past century led astronomers become certain that the universe started with the Big Bang. Their first observation was that the universe is expanding which led scientists to believe everything was super close together before some sort of explosion. Secondly, the Big Bang perfectly explains the abundance of helium and other nuclei. Only a hot, dense, and expanding environment could create the abundance of nuclei we observe today. Lastly, astronomers can actually obverse the cosmic background radiation (the afterglow of the explosion) from every direction in the universe.