EPSC 201 Lecture : EPSC201 Lecture 1 Notes.doc
11 Mar 2013
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It was initially infinite in energy and infinitely small. Since then, the universe has been expanding outwards, and cooling down. It started off as a slow expansion, and started to accelerate over time. This is be- cause as the mass got further away from other mass, the gravity was less, so it could travel even faster. As the universe expands, more energy is being converted to mass through the equa- tion e=mc^2 the universe was initially so hot, that there was no matter. It was all in the form of energy. We estimate the big bang occurred 13. 7 billion years ago. As the universe has expanded, the distance between stars and galaxies has gradually increased. Things are now found in clusters throughout the universe. Our star is relatively small, and sits on the arm of the milky way galaxy. We know all the galaxies in the universe are moving away from each other.
