Sunset is the daily disappearance of the sun below the horizon
as a result of the Earth's rotation. The atmospheric conditions
created by the setting of the sun, occurring before and after it
disappears below the horizon, are also commonly referred to as
"sunset".
The time of sunset is defined in astronomy as the moment the
trailing edge of the sun's disk disappears below the horizon in the
west. Due to refraction of light in the atmosphere, the ray path of
the setting sun is highly distorted near the horizon making the
apparent astronomical sunset occur when the sun’s disk is
already about one diameter below the horizon. Sunset should not be
confused with dusk, which is the moment at which darkness falls,
when the sun is about eighteen degrees below the horizon. The
period between the astronomical sunset and dusk is called
twilight.
The intense red and orange hues of the sky at sunrise and sunset
are mainly caused by scattering of sunlight by dust particles, soot
particles, other solid aerosols, and liquid aerosols in the Earth's
atmosphere. These enhanced red and orange colors at sunrise and
sunset are mathematically explained by the Mie theory or the
discrete dipole approximation. When there are no particulates in
the troposphere, such as after a big rain storm, then the remaining
less intense reds are explained by Rayleigh scattering of sunlight
by air molecules. Sunset colors are typically more brilliant and
more intense than sunrise colors, since there are generally more
particles and aerosols in the evening air than in the morning air.
Nighttime air is usually cooler and less windy, which allows dust
and soot particles to settle out of the atmosphere, reducing the
amount of Mie scattering at sunrise. The reduced Mie scattering
correspondingly reduces the amount of red and orange scattered
light at sunrise. Sunrise color intensities can however exceed
sunset's intensities when there are nighttime fires, volcanic
eruptions or emissions, or dust storms to the east of the viewer. A
number of eruptions in recent times, such as those of Mount
Pinatubo in 1991 and Krakatoa in 1883, have been sufficiently large
to produce remarkable sunsets and sunrises all over the world.
Cache is a berocca tube that has some of 'Trav's' special
cammo on it!!!!