Tuesday, February 08, 2005

Light and Water Vapor

sunrise

sunset Posted by Hello


A cloud is a visible mass of condensed water droplets or ice crystals suspended in the atmosphere above Earth's (or another planetary body's) surface.

The condensing water vapor forms small droplets of water or ice crystals that, when surrounded with billions of other droplets or crystals, are visible as clouds. Clouds reflect all visible wavelengths of light equally and are thus white, but they can appear grey or even black if they are so thick or dense that sunlight cannot pass through.

Sunrise, also called sunup in some American English dialects is the time at which the first part of the Sun appears above the horizon in the east. Sunrise should not be confused with dawn, which is the (variously defined) point at which the sky begins to lighten, some time before the sun itself appears, ending twilight.

Because the bending of sunlight causes the sun to be seen after it has dropped below or before it has risen above the horizon, both sunrise and sunset are daily optical illusions.

Sunset, also called sundown in some American English dialects is the time at which the Sun disappears below the horizon in the west. Not to be confused with dusk, which is the point at which darkness falls.

The red hues of the sky at sunset are caused by the Rayleigh scattering of blue light by atmospheric dust. Relatively little red light is scattered in this way, and so the sky often takes on shades of red, orange and yellow. The color of a sunset may be enhanced by atmospheric phenomena

The sunset is often more brightly coloured than the sunrise. The atmosphere responds in a number of ways to expsure to the Sun during daylight hours. In particular, there tends to be more dust in the lower atmosphere at the end of the day than at the beginning. During the day, the Sun heats the surface of the Earth, lowering the relative humidity and increasing wind speed and turbulence, which serves to lift dust into the air. However, differences between sunrise and sunset may in some cases depend more on the geographical particulars of the location from which they are viewed.

Thanks to Wikipedia for info. Thanks to Rexroth's Daughter for running out with the camera at 6 A.M.

1 comment:

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