|Timeline of the universe. Public domain image. SOURCE.|
As with astrophysics (covered on Sunday), it is a branch of astronomy. Cosmology as we think of it now began to take off in the early 1900s, when Edwin Hubble (the Hubble Telescope was named after him) made the discovery that so-called "spiral nebulae" were actually galaxies whose light was shifted toward the red end of the spectrum, a phenomenon called "red-shift"; this results when an object is in motion. He proposed that galaxies are red-shifted because they are moving away from our own, the Milky Way, which in turn led to the idea that at one point, the universe exploded from an extremely dense point in what's known as the Big Bang.
Another scientist who made major contributions to cosmology was Albert Einstein with his Theory of General Relativity (which will be explored in greater detail on Saturday), a theory that brought together space and time, formerly considered separate, into a single entity called spacetime. Einstein also came up with the idea that spacetime is curved, thanks to gravity.
|Spacetime curvature by Johnstone, CC-BY-SA-3.0. SOURCE.|
The theories that the universe might have been in one location all at one time and that spacetime is unified doesn't mean the field is over and closed, however; rather, it's very far from it. Some current questions in cosmology are whether or not the universe is really infinite, whether it will stop expanding at some point and come together in a Big Crunch (indicating that the universe might expand and contract cyclically) or everything will continue to accelerate away from each other, why there is more matter than antimatter, the role of dark matter and dark energy, and (if the Big Bang theory is true) what occurred just after the beginning of the universe (since all laws break down at that point).
|Public domain image. SOURCE.|
Stephen Hawking is probably one of science's--and cosmology's--most famous figures. He became a Research Fellow and then a Professorial Fellow at Gonville and Caius College, and took the position of Lucasian Professor of Mathematics from 1979-2009, a title formerly held by Isaac Newton; he is currently the Director of Research at the Centre for Theoretical Cosmology at Cambridge University.
He and Roger Penrose showed that the General Theory of Relativity indicated there must be unification between quantum theory and general relativity; he also came up with the theories that black holes are not black--instead, they emit radiation--and that the universe has no edge. He has published a series of scientific papers, in addition to A Brief History of Time, Black Holes and Baby Universes and Other Essays, The Universe in a Nutshell, A Briefer History of Time, On the Shoulders of Giants, the Middle Grade Fiction George's Secret Key to the Universe (and the subsequent novels in the trilogy), and his most recent The Grand Design.
At the age of 21, he was diagnosed with amyotrophic lateral sclerosis (ALS, also called Lou Gehrig's disease or motor neuron disease) and told he had one to two years left to live. But, rather remarkably, he lived far beyond that and is currently 70 years old.
Stephen Hawking received the CBE (Order of the British Empire) in 1982 and became a Companion of Honour in 1989.
A video about the universe with Stephen Hawking:
A Brief History of Time by Stephen Hawking
What do you think? Will the universe expand forever, or will it stop and begin contracting into the Big Crunch? Do you think humanity will ever figure out how the universe began and how it will end, definitively?
-----The Golden Eagle