![]() ![]() We can model this process remarkably closely (at least until the very early nanoseconds or less), and physicists have been able to piece together the major events in the evolution of universe, beginning with the tiniest fractions of a second after the Big Bang: If we were to play the movie of this expansion in reverse, we would see the universe become smaller and small as we go back in time, until ultimately the matter and energy of the whole universe is concentrated into a microscopic point some 13.8 billion years ago. In fact, we now know that this expansion is accelerating faster and faster (largely as a result of the mysterious dark energy that pervades the universe). The universe is expanding, and all the galaxies are moving further and further away from each other. Any putative events from before the Big Bang can therefore be considered effectively meaningless (or at least the province of philosophical speculation, not physics). Before the Big Bang, there just was no space or time, and you cannot go further back in time than the Big Bang, in much the same way as you cannot go any further north than the North Pole.Īs theoretical physicist Stephen Hawking notes in his 1988 book A Brief History of Time, even if time did not begin with the Big Bang, and there was another time frame before it, no information is available to us from that earlier time-frame, and any events that occurred then would have no effect on our present time-frame. This can be considered the “birth” of the universe, and the beginning of time as we know it. The general view of physicists is that time started at a specific point about 13.8 billion years ago with the Big Bang, when the entire universe suddenly expanded out of an infinitely hot, infinitely dense singularity, a point where the laws of physics as we understand them simply break down. We can model quite accurately the evolution of the universe since the Big Bang 13.8 billion years ago ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |