AST201H1 Lecture Notes - Lecture 19: Gravitational Lens, Weakly Interacting Massive Particles, Massive Compact Halo Object

• School: UTSG
• Department: Astronomy & Astrophysics
• Course: AST201H1
• Professor: Bryan Gaensler

Document Summary

Recall when zwicky used moions of galaxies i clusters to measure their mass, he got an answer higher than the amount of mass that was visible. First law: orbits are ellipses with the centre of mass of the system at one focus. Third law: the wider the orbit, the longer it takes to complete. Things closer to the sun for example, would move quicker as they closer to the sun for example. Keplerian rotaion curve describes objects moving according to kepler"s laws from above. But when looking at the milky way rubin"s predicions came to be the opposite of this predicion. Measurements have also been taken for other galaxies to see if rubin"s calculaions were wrong resulted in the same indings. This means either we are wrong about gravity or the galaxy is mainly made of mater we cannot see.