A cosmological model for the Universe, describing an event billions of years ago that allowed for the existence of atoms and life. It is commonly misunderstood by ignorant
people who think it began at a
single point in space, appeared out of nowhere or was an explosion.
The Big
Bang actually refers to a point in the Universe when it was extremely
dense, but infinitely large. About 13.8 billion years ago, matter in the Universe was much closer together and space was mostly filled with an opaque plasma of light and electrons (the Photon
Era). As a result, everything was unimaginably hot, and some scientists think that this
heat led objects to move away from each other (hotter things expand).
While there
may have been infinite matter, there is even more space through which objects can move apart. This allowed matter to continue moving away from other matter and, as a result of the expansion, the Universe began to cool down. Atoms were able to form and eventually stars and galaxies followed. In essence, one can say the Big
Bang occurred everywhere; all matter moved away from each other in the tightly packed Universe.
