Space StudyHonors Ch. 28.1Pg. 747-752

Study of Light

• Almost everything we know about the universe (space) comes by studying light from distant sources.

• Light from what?

Types of energy• Light is a type of electromagnetic radiation

(visible light)

• Other types of electromagnetic radiation• Radio waves• Microwaves• Infrared rays• UV radiation• X-rays• Gamma rays

Visible light• Light that we can see.• Longer wavelengths = less energy & redder color• Shorter wavelengths = more energy & bluer color

Light Spectrum – pg 811• Spectrum – different types of light give off

different “spectrums” (bands of color)

• 3 types• Continuous spectrum• Absorption spectrum• Emission spectrum

Continuous spectrum• Produces an uninterrupted band of color

Absorption spectrum• Produces a band of color but with some dark lines

of missing color

Emission spectrum• Only produces a few bright lines in the spectrum

Why study spectrums?• The type of spectrum tells us the types of

elements that are in the object that is producing the light.

• We can figure out what the object is made of!• Most stars produce light in the absorption

spectrum.

• Article to read as a class…• Search For Alien Life Project

Doppler Effect• Has anyone ever heard of it?• Has anyone ever heard it?• Doppler Shift Animation

Doppler Effect• Think of a train horn or ambulance siren as it

moves toward and passes you. Does it sound the same? Why?

Doppler Effect• The sound of the horn or siren sounds higher

(pitch) as it comes toward you. It sounds lower as it moves away.

• We perceive the sounds wavelengths as shorter and then longer.

Doppler Effect• The Doppler effect also occurs with light waves.• In astronomy, the Doppler effect is used to determine

if an object in space is moving toward or away from Earth.

• This redshift and blueshift will come up again when talking about our universe….

Tools for Studying Space • Telescopes• Refracting telescopes (visible light)• Reflecting telescopes (visible light)• Telescopes at other wavelengths• Space telescopes

Why use a telescope?1. Attach different detectors to telescopes to observe

all wavelengths, especially the ones humans cannot see2. Brings more light to a focus than the human eye can3. Allow astronomers to use specialized equipment4. Telescopes can be used to make time exposures with

cameras and other imaging devices

Visible Light Telescopes• Refracting telescopes – Uses lenses to focus light

on a specific spot and then magnify the image

Visible Light Telescopes• Reflecting telescopes – use lenses and mirrors to

focus and magnify light

• While refracting and reflecting are both still used today, the majority are reflectors.

Visible Light Telescopes• Both refracting and reflecting telescopes help

astronomers because

• 1) they help gather light from far away objects• 2) they help make objects more clear (resolve

power)• 3) the help magnify objects (make them appear

bigger)

Telescopes at Other Wavelengths

• Astronomers observe the universe at wavelengths the human eye cannot detect.

• Same goal: bring as much radiation as possible to a focus!

• EX:• Infrared and UV using mirrors• X rays using special designs• Gamma rays cannot be focused, so telescopes can only

determine the general direction from which the rays come.• Radio waves using a large dish with receiver

• Interferometry – linking separate telescopes together to act as one telescope

Radio Telescopes• Are used to detect radio waves from space

objects.

• Radio telescopes have recorded awesome events such as two galaxies colliding!

Space Telescopes• Telescopes are placed in space so that the Earth’s

atmosphere can’t distort the image.• They produce more clearer images than land

telescopes.

Space Telescopes• Hubble Telescope – 2.4 meters long, has 10 billion

times more light-gathering power than the human eye.

• It has produced spectacular images of planets, stars, galaxies, and deep space.

Space Telescope• Hubble Space Telescope• Far Ultraviolet Spectroscopic Explorer• Chandra X-Ray Observatory• Spitzer Space Telescope

Humans in Space• Spaceflight• International Space Station

Spinoffs• NASA technology that has been passed to

commercial industries for common use• Laser angioplasty • Cardiac imaging system• Advanced pacemaker• Infrared thermometer• Thermal video• Body imaging• Skin damage assessment

Space, the final frontier….

Nebular Theory CFA 2

1. Which color has the longest wavelength?A. redB. blueC. greenD. orange

2. Which of the following refers to the change in wavelength that occurs when an object moves toward or away from a source?

A. Doppler effectB. chromatic aberrationC. spectroscopyD. wave theory of light

3. What will happen to an object’s wavelength as the object moves toward you?

A. The wavelength will be shortened.B. The wavelength will be lengthened.C. The wavelength will not change.D. The wavelength will vary.

4. A reflecting telescope produces an image using a(n) ____.

A. concave mirrorB. lensC. prismD. antenna

5. A radio telescope produces an image using a(n) ____.

A. concave mirrorB. lensC. prismD. antenna