Astronomy

• Chapter 21 page 583

Space Exploration

• Radiation from Space – the electromagnetic spectrum ( EM spectrum)

EM Spectrum

EM Spectrum

• Visible Light ROYGBIV( Wavelength = 300 – 720 nm)

OR 3000 to 7200 Angstroms

Red - Orange – Yellow – Green-

Blue – IndigoIndigo - VioletViolet

Wavelength

• Wavelength is the distance from crest to crest. The SI unit is meters or nanometers (nm). Angstroms are another unit.

Claude Monet

Impressionists painted the effects of light.

EM Spectrum Long Wavelengths

• Radio waves

• Microwaves

• Infrared

( Then Visible Light)

EM Spectrum SHORT Wavelengths

• Ultraviolet ( UV)

• X-rays

• Gamma rays

EM Radiation : From the SUN and all STARS

• All stars give off electromagnetic radiation ( x-rays, gamma, microwaves, etc.)

• Speed of Light = 300,000 km/second

OR 186,000 mile/sec

How Fast is Light?

• Speed of sound = about 700 mi/hr

• Speed of sound is only 0.2 mi/sec

• Space shuttle flies at Mach 25 ( 17,500 mi/hr)

• This is only 5 miles /second…slow as compared to light!