1. Light and Atmospheres Greenhouse gases absorb infrared light Scattering of visible wavelengths depends on wavelength Molecular dissociation by ultraviolet light Ionization by X-rays

2. Atmospheric Layers

3. Greenhouse Effect

4. Blue Sky: Scattered Light

5. UV and X-ray Light Ozone (O 3 ) in stratosphere of Earth absorbs ultraviolet light. –Chemical balance between O 3 and O 2 –Chlorofluorocarbons (CFCs) destroy ozone X-rays ionize the upper layers of the atmosphere (ionosphere) –Charged particles reflect low frequency radio waves (e.g., AM radio)

6. Atmospheric Windows Certain wavelengths require orbiting telescopes Radio and visible light can be done from ground

7. Seeing: Atmospheric Effect

8. Why Put a Telescope in Orbit? The only reason to put a telescope in space is to eliminate atmosphere! a) ground-based b) damaged Hubble c) enhanced image d) repaired Hubble

9. Mauna Kea