Astronomy
Radiation from Space
Electromagnetic spectrum
• Radiation – energy that is transmitted from one place to another by waves.
• - it has both magnetic and electric properties
• - carry energy through vacuum and matter
• Spectrum – an array
Infrared radiation
Parts of a wave:crest – top of wave
trough – bottom of wave
Wavelength• Larger wl – slower wave travels• Less dangerous
• Smaller wl – faster wave travels
• More energy• Moredangerous• ww.pbslearningmedia.org/
resource/phy03.sci.phys.energy.nasaspectrum/the-electromagnetic-spectrum-nasa/
Frequency of a wave
Wave frequency-number of waves per second.
Important waves on EMS.• Radio waves – longest wave• Microwaves • Infrared waves – heat• Visible light – ROYGBIV, (wl from larger to smaller)• Ultra violet light – damages tissue
causes skin cancer
• X-rays – absorbed by bones• Gamma waves – radiation - very powerful - can cause radiation poisoning
- used in radiation for cancer - kills body cells
Telescopes
• Refracting – convex lens (curved outward () ) light is bend by the lens and a focal point is produced.
• - The eyepiece magnifies the image.– Two lenses used to bend
the light
Refraction - is the bending of light as it passes from one medium to another with different densities.
• Refraction of a pencil in water.
• Light waves are bent as the pencil enters the water.
• Each transparent substance bends the light at different angles.
• Reflecting – uses lens that is concave ) like a bowl. - light bounces
to a mirror that focuses image.
- mirror reflects image to eyepiece where it is magnified.
2 mirrors and concave lens
• In reflection, a light ray strikes a smooth surface and bounces off.
• A reflected ray always comes off the surface of a material at an angle equal to the angle at which the incoming ray hit the surface.
• Wavelength of color is reflected from the surface to the eye.
observatory
Hubble Space Telescope
• Launched 1990• Located outside of
earth’s atmosphere• Atmosphere distorts
images• Produces clearer images
Radio telescopes
• Collects radio waves from space
• Useful in any weather 24 hours a day
• Dish collects waves and focuses them on a receiver
• Receiver transforms the waves into electrical impulses or computer impulses
VLA The Very Large Array in New Mexico
• 27 moveable dishes• Operate as one
telescope• Most powerful radio
telescope• NOTE: Contact Youtube
pt 1 and 3
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