Astronomy #2 (Life in the Universe and Atmospheric Effects)

conditions necessary for life

liquid water

a source of nutrients

a source of energy

*Atmospheric oxygen was not necessary for life to first form

Early earth and oxygen

the first life arose before earth’s atmosphere contained the abundant oxygen present today

early organisms did not require an oxygen rich atmosphere

photosynthetic organisms later contributed to the buildup of oxygen in Earth’s atmosphere

many organisms today require oxygen, but that does not mean oxygen was required for life to orginate

Rayleigh Scattering and the Blue Sky

atmospheric molecules scatter shorter wavelengths of visible light more effectively than longer wavelengths

blue light is scattered more strongly than red light

this scattering makes the sky appear blue when we look away from the direct light of the sun

Rayleigh Scattering and the Blue Sky

atmospheric molecules scatter shorter wavelengths of visible light more effectively than longer wavelengths

blue light is scattered more strongly than red light

this scattering makes the sky appear blue when we look away from the direct light of the sun