User:Nickwogan/sandbox pale blue dot

Notes:


 * 1) Delete existing sentence on why Earth is a pale blue dot.

Why is the Earth a Pale Blue Dot?
Earth is a blue dot primarily because of Rayleigh scattering in its atmosphere. In Earth’s air, short wavelength visible light is scattered much more than long wavelength visible light. Blue light is short wavelength in the visible spectrum, therefore, blue sunlight is scattered in Earth’s atmosphere to a greater extent than longer wavelength light (e.g. red), which is the reason why the sky appears blue from Earth. The ocean contributes to Earth’s blueness, but to a lesser degree than scattering. Earth is a pale blue dot rather than dark blue because of clouds, which reflect all visible sunlight. The combination fo the white light reflected by clouds and the scattering of blue light is why Earth is pale blue when viewed from space.

Earth’s reflectance spectrum from the far-UV through the visible to the near-Infrared is unlike any other observed planet's and is partially due to biology. Rayleigh scattering, which causes Earth's blueness, is enhanced in an atmosphere that does not substantially absorb visible light, unlike, for example, the orange-brown color of Titan where organic haze particles absorb strongly at blue visible wavelengths. Earth’s plentiful atmospheric oxygen, which comes from photosynthetic biology, causes the atmosphere to be transparent to visible light which allows for substantial Rayleigh scattering.