Search results
Results from the WOW.Com Content Network
The blue sky spectrum contains light at all visible wavelengths with a broad maximum around 450–485 nm, the wavelengths of the color blue. Diffuse sky radiation is solar radiation reaching the Earth 's surface after having been scattered from the direct solar beam by molecules or particulates in the atmosphere .
Natural light sources in a night sky include moonlight, starlight, and airglow, depending on location and timing. The fact that the sky is not completely dark at night can be easily observed. Were the sky (in the absence of moon and city lights) absolutely dark, one would not be able to see the silhouette of an object against the sky.
Optical imaging using a 10,000 frame-per-second high speed camera showed that sprites are actually clusters of small, decameter scale, (10–100 m or 33–328 ft) balls of ionization that are launched at an altitude of about 80 km (50 mi) and then move downward at speeds of up to ten percent the speed of light, followed a few milliseconds later ...
An example of this phenomenon is when clean air scatters blue light more than red light, and so the midday sky appears blue (apart from the area around the Sun which appears white because the light is not scattered as much). The optical window is also referred to as the "visible window" because it overlaps the human visible response spectrum.
The Rayleigh sky model describes the observed polarization pattern of the daytime sky. Within the atmosphere, Rayleigh scattering of light by air molecules, water, dust, and aerosols causes the sky's light to have a defined polarization pattern. The same elastic scattering processes cause the sky to be blue.
Orange hues are usually seen at certain times of the day, which is why at some points the sky has a more gray-ish haze and other times it's orange. What a difference a day makes!
Sky brightness refers to the visual perception of the sky and how it scatters and diffuses light. The fact that the sky is not completely dark at night is easily visible. If light sources (e.g. the Moon and light pollution ) were removed from the night sky , only direct starlight would be visible.
Some conspiracy theorists have come up with some pretty compelling arguments that seem to question the reality -- but the scientists have answers too. Here are the big points -- and they're ...