ESC-1000 Lecture Notes - Lecture 1: Formation And Evolution Of The Solar System, Accretion Disk, Non-Inclined Orbit
20 Feb 2017
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Document Summary
A huge explosion that happened 13. 8 bit years ago and started the expansion of the universe. Doppler effect and redshift due to universe expansion. Distant galaxies are uniformly red shifted, rather than blue shifted; this implies that they are all moving away from us. The farthest galaxies are those that are most strongly red shifted, meaning that they are receding fastest. Extrapolation of velocities and trajectories into the past suggests that all matter in the. Universe was contained in a single point, approximately 13. 7 billion years ago. At that time, the universe explosively came into existence (hence the name big bang). Stars, including our sun, are nuclear fusion reactors. For most of their life histories (on the order of billions of years), hydrogen atoms are fused together to form helium. Later stages in stellar evolution include fusion of helium atoms and other, heavier elements; ultimately, iron is the heaviest element that can be produced through fusion reactions within stars.
