North America at night from space
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North America at night from space
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North America at night from space. What are some things we (you) understand about light?. Light can be: broken up into component colors absorbed reflected Light has energy. Wavelengths of Light. Gamma Ray. Radio. Visible. X-ray. Ultraviolet. Infrared. - PowerPoint PPT Presentation
Transcript of North America at night from space
North America at night from space
What are some things we (you) understand about light?
Light can be: broken up into component colors
absorbed reflected
Light has energy
Wavelengths of Light
Visible Infrared RadioUltravioletX-rayGamma Ray
Bright matter can be dark at some wavelengths.
(Luckily) Earth’s atmosphere absorbs light
Dark Matter
Why so we think it exists?
What is Dark Matter made of?
What is Dark Matter?
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.
Dark Matterversus
“Faint Matter”
M81-Spiral Galaxy
Visible(Optical
)Radio
M20 - The Trifid Nebula
Why study dark matter?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.
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?
What is Dark Matter? Dark matter is the name given to matter that cannot be detected in ANY wavelength of light.
Evidence for Dark Matter in the Milky Way
Motions of stars near the sun tell us that there must be dark matter in our galaxy beyond the location of the sun.
Evidence from other galaxies
The motions of stars and gas, i.e. measurements of galaxy rotation curves, show that matter MUST be located beyond the radius
where stars and gas are observed.
Gravitational Lensing
At Earth
LensedImage
DistantStar
Massive object
Gravitational LensingGravitational Lensing
is one method by which we can determine the mass of galaxy or galaxy cluster.
Observer at Earth
Object
Image (ring)
Lensing Galaxy orGalaxy Cluster (with Dark Matter)
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.
What is Dark Matter?Baryonic dark matter
Massive Compact Halo Objects (MaCHOs)
Brown dwarfsCooling white dwarfsBlack holes
Gliese 229B
Ring NebulaBlack Hole
What is Dark Matter?
Non-baryonic dark matterWeakly Interacting Massive particles
(WIMPs)Hot Dark Matter
NeutrinosCold Dark Matter
NeutralinosAxions
Summary1. 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
Pulkovo Observatory, St. Petersburg, Russia
That’s me! That’s President Obama!
Thank you!
