PRESENTATION Ames Area Amateur Astronomers (AAAA) Saturday, February 21, 2015 Dark Matter and Dark Energy are huge mysteries in Astronomy. The observational evidence for both will be presented, including the observations and experiments under way to understand what Dark Matter is. Bio: Sam Wormley is a retired Associate Scientist and Principal Investigator at Iowa State and a retired Adjunct Prof of Astronomy at Marshalltown Community College. Sam regularly teaches science classes for the Osher Lifelong Learning Institute at Iowa State and for the RaySociety at Drake University. Astronomer's Tools - Spectral lines - Doppler shift http://edu-observatory.org/olli/tobbc/Week1.html Dark Matter - Galactic Rotation rates as measured by Doppler Shift of stars and gas - Motion of Galaxies in a cluster as measured by Doppler Shift of stars and gas - Gravitational Lensing (to determine mass of a cluster of galaxies) http://apod.nasa.gov/apod/ap111221.html http://apod.nasa.gov/apod/ap140715.html http://apod.nasa.gov/apod/ap111017.html - X-Ray imagery to determine the location and density of hot gas in galactic clusters http://edu-observatory.org/olli/Hubble/Week6.html - Dark Matter Candidates http://edu-observatory.org/olli/tobbc/Week8.html Dark Energy - Observation (Doppler and Brightness) of Type Ia supernovae - Observations of the CMB http://edu-observatory.org/olli/Hubble/Week7.html Summary -- the actual observation are of electromagnetic radiation, but as you can see above can be used to measure, motion within clusters and within galaxies, and gravitation effects to measure mass.