Astronomy 1021 Lecture Notes - Lecture 18: Galaxy Formation And Evolution, White Dwarf, Gravitational Lens

• School: Western University
• Department: Astronomy
• Course: Astronomy 1021
• Professor: Chris Racknor

Document Summary

Notes chapter 18 dark mat er, dark energy, and the fate of the universe. Dark mater is the name given to mass that emits no detectable radiaion; we infer its existence from its gravitaional inluence. Dark energy is the name given to the unseen inluence that causes the expansion of the universe to accelerate with ime. Orbital speeds in the milky way remain high even very far from the centre, indicaing that large amounts of dark mater lies beyond our galaxy"s visible regions. Orbital speeds in the outer regions of other galaxies indicate that they, too, harbour lots of dark mater. The orbits of galaxies in clusters tell is that galaxy clusters contain huge amounts of dark mater. Temperature measurements of hot gas also tell us the amount of dark mater in clusters, and give results that agree with those we infer from galaxy velociies. Occurs because masses distort space-ime- the fabric of he universe.