The beginning of everything: the Big Bang. The idea that the universe was suddenly born and is not infinite. Out of the middle of the twentieth century, most scientists thought of the universe as infinite and ageless. Until Einstein's theory of relativity gave us a better understanding of gravity and Edwin Hubble discovered that galaxies are moving apart from one another in a way that fits previous predictions. In 1964 by accident, cosmic background radiation was discovered, a relic of the early universe which together with other observational evidence made the Big Bang the accepted theory in science. Since then, improved technology like the Hubble telescope has given us a pretty good picture of the Big Bang and the structure of the cosmos. Recent observations even seem to suggest that the expansion of the universe is accelerating, but how did this Big Bang work? How can something come from nothing? Let's explore what we know
We can ignore the beginning part for now. First of all, the Big Bang was not an explosion. It was all space stretching everywhere all at once. The universe started very, very, very small, and quickly expanded to the size of a football. The universe didn't expand into anything; space was just expanding into itself. The universe cannot expand into anything, because the universe has no borders. There is, by definition, no "outside the universe". The universe is all there is
In this hot dense environment, energy manifested itself in particles that existed only for the tiniest glimpses of time. From gluons, pairs of quarks were created which destroyed one another, perhaps after giving off more gluons. These found other short lived quarks to interact with, forming new quark pairs and gluons again. Matter and energy were not just "theoretically" equivalent; it was so hot, they were practically the same stuff. Somewhere around this time, matter won over anti-matter. Today we're left with almost all matter and nearly no anti-matter at all. Somehow, one-billion-and-one matter particles were formed for every billion particles of anti-matter
Instead of one ultimate force in the universe, there were now several refined versions of it acting under different rules. By now the universe has stretched to a billion kilometres in diameter, which leads to a decrease in temperature. The cycle of quarks being born and converted back to energy suddenly stops; from now on, we work with what we have. Quarks begin forming new particles, hadrons, like protons
