Theories of the Universe: It's Out of Control

It's Out of Control

This then is the state of big bang cosmology today. The general consensus is that omega is equal to one and that the shape of the universe is flat. So what does this mean? What have astronomers and cosmologists discovered about what's happening in the cosmos to reflect this? Well one of the most significant things that appears to be happening right now is that the speed at which the universe is expanding is accelerating. The universe is flying apart at ever increasing speeds. Right now, the 100 billion galaxies that we can see with our telescopes will recede out of range one by one. (Of course, we're talking about hundreds of millions of years before this happens.) Tens of billions of years from now the Milky Way will be the only galaxy we'll be able to see. But by then our sun will have shrunk to a white dwarf (a very compact star close to the end of its life and which emits white light) that will be providing very little light and heat to who or whatever is left on earth. But in cosmological time, billions of years is very small. The universe will continue to exist; each of the stars and suns in all of the galaxies will slowly burn out. By the time the universe is one trillion trillion trillion trillion trillion years old, all the dead matter will collapse into black holes, and these will eventually disintegrate into stray particles occasionally running into each other. So what was once a universe lit by countless stars and galaxies will end up being a vast, empty, dark and unimaginably lonely place. And with that cheerful thought we'll bring this section to a close.