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

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