1. Dark Matter cannot be seen directly with telescopes; it neither emits nor absorbs light; estimated to constitute 84.5% of the total matter in the universe – and 26.8% of the total mass/energy of the universe; its existence is inferred from gravitational effects on visible matter and gravitational lensing of background radiation;

2. Rotational curves for a typical galaxy indicate that the mass of the galaxy is not concentrated in its center. Our own galaxy is predicted to have a spherical halo of dark matter.

3. Vera Rubin and Flat Rotation Curves Dark Matter Close to Home

4. Visualization of dark matter halo for spiral galaxy

5. Candidates for nonbaryonic dark matter Axions (0 spin, 0 charge, small mass) Supersymmetric particles (partners in SUZY) Neutrinos (possibly small fraction) Weakly interacting massive particles.. so far none have been positively detected.

6. Gravitational Lensing

7. Theorized structure of dark matter.

8. We know dark matter exists … we don’t know what kind of particles comprises it!