Electromagnetic Spectrum What’s the Wavelength?

E-M Spectrum

Radio Waves Relative size: 100’-60 mi Frequency: low Amazing Facts Earth’s Atm: –bend easily around curve of Earth –Penetrate dust & gas Use –communication

Radio Waves Telescopes –Arecibo, PR What we “see” –Active galaxies –Pulsars –Quasars –Supernovae remnants Wow…cool facts

Microwaves Relative size: 1mm - 1 m Frequency: 10 9 Amazing Facts Earth’s Atm –Pass freely through the air Use –Cell phones –TV –cooking

Microwaves Telescopes What we “see” –Cosmic background radiation Wow…cool facts

Infrared Relative size: 1/10 inch (sand grain) Frequency Amazing Facts –Warm objects give off IR Earth’s Atm –Absorbed by Earth’s CO 2 & H 2 O in atm. –Can not be used for communication Use –Heat signature applications

Infrared Telescopes: –Hubble ST –Keck –Spitzer –ISO (Infrared Space Observatory) What we “see” –Young stars with outflowing gases –planets Wow…cool facts

Visible Relative size: bacteria Frequency Amazing Facts: ROY G. BIV Earth’s Atm: –Allows frequency through Use –dah

Visible Telescopes –Twin Keck –Kitt Peak, Tucson AZ –HST –National Optical Astro. Observatory –Optical telescopes What we see –Stars –sun Wow…cool facts

Ultraviolet Relative size: virus; atom Frequency Amazing Facts –Can kill or disrupt human cell reproduction Earth’s Atm –Ozone absorbs UV –Can cause sunburn Use –Sterilize medical equipment

Ultraviolet Telescopes: –HST –SOHO –EUVE Extreme UV Explorer What we “see” –Hot stars –Sun’s corona Wow…cool facts

X-Ray Relative size: atom Frequency Amazing Facts –Penetrate through soft materials Earth’s Atm –Absorbed in Earth’s upper atmosphere Use –To “see” through less dense materials

X-rays Telescopes: –Chandra –ROSAT (Roentgen Satellite) What we “see” –Black holes –Collapsed stars –Between galaxies –Exploded star’s hot gases Wow…cool facts

Gamma Rays Relative size: nuclei Frequency: HIGH Amazing Facts –Pass through most solids –Most energetic Earth’s Atm –Blocks gamma rays Use –bombs

Gamma Rays Telescopes –Compton Telescope What we “see” –Black holes –Neutron stars –Supernovae –Pulsars –Quasars –Exploding stars Wow…cool facts