How we See the Universe

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Putting it into perspective

When we organize light waves in this type of order, we call it the

“Electromagnetic Spectrum” or EMS

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Wavelength = distance between crestsAmplitude = half the height of trough to crestFrequency = number of crests that pass a point in space every second

… so wavelength = speed / frequency

Do the wave

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What does the EMS tell us?(Electromagnetic Spectrum)

• Transports energy• Electric and magnetic

fields oscillate: that’s the “wave”

• Moves at speed of light, 3 x 108 m/s

• Wavelength, frequency, energy all related

• Type of radiation (usually) depends on energy/temperature of object

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http://imagers.gsfc.nasa.gov/ems/atmosphere.gif

I like a place with a little atmosphere…

Only visible, radio and some IR and UV gets through the air!

To see gamma rays, X-rays, most UV and some IR you must go to space

Spitzer Infrared Video

Different Views from the Inside

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Sources

Name some visible sources of light in the room

Is the wall at the front of the room a light source?

Definition: Sources of light are objects that emit light energy

Flashlight Projector Laptop Monitor

But it seems to be emitting light?Oh, I see the wall is reflecting the light, not emitting it.

What is a light source?

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What is a detector?

Detectors

Are there any other light detectors that you know of?

Those two openings on either side of our noses!

Solar Calculators

Cameras

Can you tell me where there are light detectors in this room?

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Transmitters and Shields

What are some things that don’t allow light through?Is it safe to say these things “Shield the

Light”?

What are some materials we know of that do allow light to either completely or partially pass through it?

Is it safe to say these things “Transmit the Light”?

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Invisible Sources of Light

• There are 6 different stations throughout the room.

• They are equipped with a source of invisible light and a detector for detecting that light.

• In a moment we will break up into groups.

• Each station will have a set of materials.

• These materials are potential shields.

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Procedure

• Each group will go from station to station. You have about 5 minutes per station.

• As scientists we are obligated to make a prediction about how we think each material will behave. DO THIS FIRST!

• Then test each material at each station to see if it is a Transmitter (T) or a Shield (S) for that particular type of light.

• Try to determine the common properties of the materials that block the different types of light

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Stations:

• AM Radio

• Infrared lamp

• Flashlight

• FM Radio

• Remote control

• “Black” light

Let’s Get Busy!

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What did we learn?

What property of the materials we tested caused radio waves to be blocked?

Are all the plastics we tested translucent/transparent to infrared light?

If someone had no sunscreen while at the beach what could they cover their face with to keep from getting sun burned by UV light?

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M45 – The Pleiades Cluster

X-ray: T. Preibisch Ultraviolet: MSX Visible: AAO

Infrared: IRAS Radio: NVSS

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Multi-wavelength Crab Nebula

X-ray: Chandra Ultraviolet: UIT Visible: Palomar

Infrared: 2MASS Radio: VLA

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M51 – The Whirlpool Galaxy

X-ray: Chandra Ultraviolet: GALEX Visible: T. & D. Hallas

Infrared: ISO Radio: VLA