AST201H1 Study Guide - Final Guide: Horizontal Branch, Weakly Interacting Massive Particles, Maltese Lira
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AST201H1 Full Course Notes
Verified Note
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Document Summary
Fritz zwicky- missing mass idea- calculated gravitational mass of galaxies and got a value 400x greater than expected from luminosity, so most of matter was dark . Contents of universe: 4. 9% = normal matter, 26. 8% = dark matter, Lecture 2 speed of light is invariant- same in all frames of reference: always travels at c (in a vacuum), no object with mass can ever reach or exceed light speed. = length contraction someone moving relative to you- their lengths appear shorter therefore space and time are not separate- they are bound together- spacetime. Both observers will see each others" clocks as moving slower than their own- so when both twins reunite, they both expect the other to be younger. Only a paradox if we pretend they"re interchangeable but they"re not because one changes from one reference frame to another, the other twin doesn"t. Zoomer sees stayer"s clock as complicated when zoomer decelerates and turns around.
