1. Galaxies

2. Our Galaxy (CP Fig 19.1a)

3. Our Galaxy (CP Fig 19.1b)

4. Orbits of stars (CP Fig 19.18)

5. Spectral lines viewed through diffraction grating Redshift Blueshift Observing Galactic Rotation

6. The result: A rotation curve NB, there is an overall net redshift due the the cosmic expansion.

7. Rotation Curves

11. 1996

12. Mass inferred from lensing: Must have dark matter

13. Theoretical studies of Galaxies Images and movies from the Virgo consortium Another Virgo Link Galaxy collision movies