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Energy From Space
• Almost all of the energy in the
universe comes from stars
• Stars are powered by nuclear
fusion: joining together (“fusing”)
the nuclei of two atoms
Nuclear Fusion
• Involves the very smallest atoms
(Hydrogen and Helium)
• Hydrogen nuclei are joined together
to form a Helium nucleus
• Two isotopes of Hydrogen (left) fuse
together to form one nucleus of
Helium (right)
Fusion Energy
• Nuclear fusion
releases large
amounts of
energy
• Modern
nuclear
weapons
rely on
fusion
reactions
• In our sun, about four million tons of
matter is converted to energy every
second
Fusion Video
• Stars release
many types of
energy (besides
heat and light)
• All types of
energy from stars
is called
Electromagnetic
Radiation
(“E.M.R.”)
E.M.R. = all types of energy that
travels through space in waves
• Different kinds of EMR have different wavelengths
• Wavelength = distance from the crest of one wave to
the next
Speed of EMR
• All E.M.R. travels at the “speed of
light” = 300,000 kilometers per
second (km/sec)
• Light Year = the distance light
travels in one year = 9.5 trillion
kilometers
Electromagnetic Spectrum
Forms of Electromagnetic Radiation
(EMR)
A Quick Tour of the
Electromagnetic Spectrum
Note-taking: for each type of radiation,
describe:
• Where it lies on the EMS (wavelength)
• How humans use it
• How it affects us (or other life forms)
NASA: Electromagnetic Spectrum Basics (30:35)
1. Radio Waves
Longest wavelengths
Used for communication
Astronomers use radio
telescopes
Very Large Array (VLA)
Used for “listening-in” to deep space
Radio Wave Imagery
Radio (red) and X-Ray (green) image of
the center of the Milky Way
Radar Imagery
(radio detecting and ranging)
2. Microwaves
Used for communication
(cell phones)
Microwave Imaging Satellite
Microwave Imagery
3. Infrared Imagery
Often used to detect heat differences (thermal imaging)
Used for night-vision
Infrared is used in Weather Forecasting
Infrared helps astronomers to find the
temperature of objects in space
Infrared image of
a nebula in
Sagitarius
Some reptiles (pit vipers)
can “see” in infrared
4. Visible Spectrum
Astronomer use optical telescopes
to view images of space
Refracting telescopes use lenses to magnify images
Reflecting telescopes use curved mirrors to magnify images
5. Ultraviolet radiation
• Wavelengths too short for humans to see
• Causes sunburn and skin cancer
• Some insects (ex. bees) can see
ultraviolet
Ultraviolet Flower Images
Appearance in
visible light
Appearance in
ultraviolet light
Ultraviolet Flower Images
Appearance in
visible light
Appearance in
ultraviolet light
Ultraviolet Flower Images
Appearance in
visible light
Appearance in
ultraviolet light
(ultraviolet radiation)
Used in “blacklights” and fluorescent lights
Fluorescent pigments will produce their own light
(glow) when struck by UV light.
6. X-Rays
Used in medicine
Long exposure to
X-rays is dangerous
to humans
Astronomer use X-ray telescopes to find
unusual features in the universe
Chandra X-Ray Telescope
X-ray image of a supernova
remnant in the Large
Magellenic Cloud
X-ray emission from black hole in
Cygnus
7. Gamma Rays
•
•
•
•
Shortest wavelengths
Highest energy
Released by nuclear reactions
Very dangerous to humans
Gamma ray bursts from supernova remnant
A spectrascope separates a light beam
into its various colors (spectrum)
Not all “rainbows” are the same!
Different elements produce
different spectra (rainbows)
when they emit light:
• Colors produced by individual
elements are called emission spectra
Emission spectra of individual elements
are “pieces” of the visible spectrum:
 Entire visible spectrum
 Sodium
 Mercury
 Hydrogen
 Helium
Spectrometers use emission spectra to
determine the elements in a substance
The spectra from stars and nebulae
can be analyzed to determine the
elements they contain