North America at night from space

Light can be: broken up into component colors broken up into component colors absorbed absorbed reflected reflected Light has energy

Visible Infrared Radio UltravioletX-ray Gamma Ray Bright matter can be dark at some wavelengths.

Why so we think it exists? What is Dark Matter made of? What is Dark Matter?

Why so we think it exists? What is Dark Matter made of? What is Dark Matter? Dark matter is the name given to matter that cannot be detected in ANY wavelength of light.

Visible(Optical) Radio

1. It is most of the matter in the universe! Dark matter could comprise as much as 90% of the matter in the universe. 2. It impacts our understanding of the beginnings of the universe. That is, how stars, galaxies, and galaxy clusters are able to form both now and early on. 3. It’s important in determining the ultimate fate of the universe. 4. It has an affect on (biases) how the distant universe appears to us.

Why so we think it exists? We see evidence of it by looking at Bright Matter. Because although it is dark it still has GRAVITY associated with it! What is Dark Matter made of? What is Dark Matter? Dark matter is the name given to matter that cannot be detected in ANY wavelength of light.

Motions of stars near the sun tell us that there must be dark matter in our galaxy beyond the location of the sun.

The motions of stars and gas, i.e. measurements of galaxy rotation curves, show that matter MUST be located beyond the radius where stars where stars and gas are and gas are observed. observed.

At Earth Lensed Image Distant Star Massive object

Gravitational Lensing is one method by which we can determine the mass of galaxy or galaxy cluster. Observer at Earth Object Image (ring) Lensing Galaxy or Galaxy Cluster (with Dark Matter)

Why so we think it exists? We see evidence of it by looking at Bright Matter. Because although it is dark it still has GRAVITY associated with it! What is Dark Matter made of? We don’t know! What is Dark Matter? Dark matter is the name given to matter that cannot be detected in ANY wavelength of light.

Baryonic dark matter Massive Compact Halo Objects (MaCHOs) Brown dwarfs Cooling white dwarfs Black holes Gliese 229B Ring Nebula Black Hole

Non-baryonic dark matter Weakly Interacting Massive particles (WIMPs) Hot Dark Matter Neutrinos Cold Dark Matter Neutralinos Axions

1.To study astronomical objects we must rely only on the light we receive from them to do our experiments 2.Therefore, Astronomers must understand something about light. 3.We rely on objects that give off light to tell us about Dark Matter. 4.We have a ways to go before we understand exactly what Dark Matter is but we see its effects in dramatic ways. 5.Astronomy is FUN!

Comet McNaught over La Serena, Chile 2007

That’s me! That’s President Obama!

Thank you!