Solar Energy in the Atmosphere

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Solar Energy in the Atmosphere

• Section 23.2

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Radiation

• All of the energy that the Earth receives from
  the sun
• It travels through space in the form of waves
• Unlike heat from conduction or convection (they
  need material to travel through), radiant energy
  can travel though space

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Laws Governing Radiation

• 1.) All objects, at any temperature, give off
  radiant energy (even the ice caps do)
• 2.) Hotter objects radiate more total energy per
  area than colder objects.
• 3.) The hottest radiating bodies produce the
  shortest wavelengths of maximum radiation (higher
  frequency)
• 4.) Good absorbers are good emmitters.

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Electromagnetic Spectrum

• Classifies all forms of radiation by wavelength
• Short wavelengths ultraviolet, X rays, gamma
  waves
• Long wavelengths Infrared ,Microwaves, Radio
  waves
• Visible light falls inbetween

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Radio Waves

• Your TV, Cable, Cell Phones
• Wavelengths AMltTVltFM

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Microwaves

• They are absorbed by water, fats, and sugars
• Once they are absorbed, they are converted into
  heat
• Not absorbed by plastics or glass, but reflected
  by metals

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The Doppler Effect

• As you moves away from a source of energy, the
  amount of energy you receive decreases (the
  wavelength increases)
• Doppler Radar (as clouds move in, higher
  frequencies of sound are reflected, when clouds
  move away, lower frequencies are reflected)

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What this all has to do with the Big Bang?

• The Doppler Effect and Red Shift support the Big
  Bang Theory
• By detecting a pattern of evenly distributed
  levels of Background Radiation (energy from
  cosmic rays, etc.), one can conclude that our
  Universe came from one source and is expanding

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More uses of the electromagnetic spectrum

• Spectroscopy- determines the composition of stars
• Elements in the periodic table yield certain
  color patterns when exposed to light
• Three types of spectra bright line (emission),
  dark line (absorption), and continuous

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