Astronomy 1021 Lecture Notes - Drake Equation, Cosmic Microwave Background, Strong Interaction

• School: Western University
• Department: Astronomy
• Course: Astronomy 1021
• Professor: Reynold Silber

Document Summary

Some galaxies have different characteristics (ie. hot gases) Haven"t been able to measure of observe dark matter (what is it?) Fritz zwicky first one to make idea of dark matter (1930s) Stars closer to the center of the galaxy will move faster. Elliptical galaxies have dark matter but its measured in a different way. Dark matter is found in large areas to have stronger effects in galaxy clusters. X-ray observations show that the hot gas between the clusters has enough mass to hold clusters together. Measure galazy clusters masses from velocities of member galaxies or the temperature of intraclusters. Only 10% of universe we can see, rest is hidden in darkness. Gravitational lensing when a galaxy hides what is on each side from the other. 90% of galaxies clusters are dark matter. The total mass of cluster"s stars does not tell us the mass of the cluster of galaxies.