In A Brief History of Time by Stephen Hawking There were very many interesting theories and facts that were brought up about physics. A couple of these theories and fact help lead me to deciding on my opinion about the future of physics in the 21st century. My opinion is that in the 21st century a couple of things will happen in the way of physics. First I think scientist will continue work on old experiments and make new theories. Another one of my thought are that scientist will prove previous theories wrong. The continuation of scientist finding out more theories and furthering previous experiment is a big possibility. This is likely to happen because since about 200 BC scientist and philosophers have been making theories about Earth and how things on Earth work as well as in the Universe. One of the earliest examples of these theories was Aristotle. Aristotle thought that the Earth was stationary and that the sun, the moon, the planets and the stars moved in circular orbits around the earth. Then in the 2nd century ad , Ptolemy made a model which elaborated the theory made by Aristotle. In his model "The earth stood at the center, surrounded by eight spheres that carried the moon, the sun, the stars and the 5 planets known at the time. Years and years after all these first theories of how the universe was setup scientist found that all the planets revolve around the sun. This is an example of how was seems so simple now like how the planets work was so complicated to our predecessors, and as for what I think, what we find so complicated right now will be so simple in later decades. I also believe that in the 21st century scientist will prove that previous theories that were made by scientist are false. Stephen Hawking sums this up by saying "At the beginning of this century, it was thought that everything could be explained in terms of properties and continues matter which shows how quickly things can change in ...