The Solar Backscatter Ultraviolet instrument currently onboard the NOAA-16 polar orbiting satellite measures the ultraviolet sunlight scattered by the Earth's atmosphere at several wavelengths ranging from 252 nanometers (nm) to 340 nm.
"Most of what Hubble sees is sunlight scattered from microscopic particles," explained Hal Weaver of The Johns Hopkins University Applied Physics Laboratory in Laurel, Md., who led the Hubble investigation.
Surprisingly, the birds are not influenced by the position of the sun itself, but by the directional polarization of sunlight scattered by the atmosphere - the "Rayleigh scattering" responsible for the blue color of the sky.
He filled his cupped palm with sunlight, then scattered it off his fingertips in lines of delicate filigree.
Caused by sunlight scattered by space dust in the zodiacal cloud, it is so faint that either moonlight or light pollution renders it invisible.
Based on the amount of sunlight scattered by the Martian atmosphere, he set an upper limit of 1/15 the thickness of the Earth's atmosphere.
It was sunlight, scattered by dust that orbited the Sun in the plane of the planets.
The long martian twilight (compared to Earth's) is caused by sunlight scattered around to the night side of the planet by abundant high altitude dust.
Ozone is measured as a ratio of sunlight incident on the atmosphere to the amount of sunlight scattered back into space.
Direct normal radiation, a measure of sunlight intensity, not counting sunlight scattered by atmosphere.