Astrophysics
From Simple English Wikipedia, the free encyclopedia
Astrophysics is the study of how stars work, and how we can learn about them.
Astrophysics is also the study of how the universe started and how it is changing with time. This part of astrophysics is called cosmology.
[edit] History
A long time ago, during the time of the ancient greeks, people thought that the way things worked in the sky was different to the way things worked on earth. They also thought that you could not study how things in the sky worked. This was because you could not do experiments on things in the sky, but you can do experiments with things that are on the surface of the earth.
When people realized that by looking at the sky they were able to work out how the planets moved, the science of astrophysics was born. The first people to write books on how they thought the planets moved were Galileo, Kepler and Copernicus.
Sir Isaac Newton realized that the same rules of mechanics that he had found on the surface of the earth also could be used to predict how the planets moved. He said "As above, so below". By this he meant that we can study how things work on this planet to find out how things work in space.
Later scientists found that by looking at the light from stars they were able to work out from what they were made. This process is called spectroscopy.
