Defense's question: Jodi, which way is the sky? Up or down?
Jodi's answer: The sky, also known as the celestial dome, commonly refers to everything that lies a certain distance above the surface of Earth, including the atmosphere and the rest of outer space. In the field of astronomy, the sky is also called the celestial sphere. This is an imaginary dome where the sun, stars, planets, and the moon are seen to be traveling. The celestial sphere is divided into regions called constellations. Usually, the term sky is used from the point of view of the Earth's surface. However, the exact meaning of the term can vary; in some cases, the sky is defined as only the denser portions of the atmosphere, for example.
The Crescent Moon remains visible just moments before Sunrise.
During daylight, the sky appears to be blue because air scatters blue sunlight more than it scatters red.[1][2][3][4] At night, the sky appears to be a mostly dark surface or region scattered with stars. During the day, the Sun can be seen in the sky, unless obscured by clouds. In the night sky (and to some extent during the day) the moon, planets and stars are visible in the sky. Some of the natural phenomena seen in the sky are clouds, rainbows, and aurorae. Lightning and precipitation can also be seen in the sky during storms. Birds, insects, aircraft, and kites are often considered to fly in the sky. As a result of human activities, smog during the day and light pollution during the night are often seen above large cities.
Contents [hide]
1 During the day
2 Dusk and dawn
3 During the night
4 Use in weather forecasting
4.1 Tropical cyclones
5 Use in transportation
6 Significance in mythology
7 Gallery
8 See also
9 References
10 External links
During the day
A greater proportion of blue light scattered by the atmosphere relative to red light.
Civil, nautical, and astronomical twilight. Dusk is the end of evening Twilight[5]
Dawn is the beginning of morning Twilight.
See also: Atmospheric optics
Except for light that comes directly from the sun, most of the light in the day sky is a result of scattering, which is dominated by a small-particle limit called Rayleigh Scattering. The scattering due to molecule sized particles (as in air) is greater in the forward and backward directions than it is in the lateral direction.[6] Scattering is significant for light at all visible wavelengths, but it is stronger at the shorter (bluer) end of the visible spectrum, meaning that that the scattered light is more blue than its source, the sun. The remaining sunlight, having lost some of its short wavelength components, appears slightly less blue. Although violet, not blue, is the color with the shortest visible wavelength, the spectrum of light emission from the sun is not constant at all wavelengths, and additionally is partially absorbed by the high atmosphere, so there is less violet in the light. Human eyes are also less sensitive to violet than blue. [4]
Scattering also occurs even more strongly in clouds. Individual water droplets exposed to white light will create a set of colored rings. If a cloud is thick enough, scattering from multiple water droplets will wash out the set of colored rings and create a washed out white color.[7]
The sky can turn a multitude of colors such as red, orange, purple and yellow (especially near sunset or sunrise) when the light must pass through a much longer path (or optical depth) through the atmosphere. Scattering effects also partially polarize light from the sky, most pronounced at an angle 90? from the sun. Scattered light from the horizon has traveled through as much as 38 times the atmosphere than has light from the zenith, causing it to lose blue components. The result is a blue gradient ? vivid at the zenith, pale near the horizon.[8] Because red light scatters as well if there is enough air in between the source and the observer, these longer wavelengths of light will also scatter significantly, making parts of the sky change color during a sunset. As the amount of atmosphere nears infinity, the scattered light appears more and more white.[9]
The sun is not the only object that may appear less blue in atmosphere. Far away clouds or snowy mountaintops will seem yellow as well; that effect is not obvious on clear days, but very pronounced when clouds are covering the line of sight reducing the blue hue from scattered sunlight.[9] At higher altitudes, the sky trends to darker colors, since scattering is reduced due to lower air density; an extreme example is the moon, where there is no atmosphere and no scattering, making the sky on the moon black even when the sun is visible.[10]
Sky luminance distribution models have been recommended by the International Commission on Illumination (CIE) for the design of daylighting schemes. Recent developments relate to ?all sky models? for modelling sky luminance under weather conditions ranging from clear sky to overcast.[11]
Dusk and dawn
Main articles: Earth's shadow, Green flash, and Sky brightness
The intensity of the sky varies greatly over the day and the primary cause differs as well. When the sun is well above the horizon, direct scattering of sunlight (Rayleigh scattering) is the overwhelmingly dominant source of light. However, in twilight, the period of time between sunset and sunrise, the situation is more complicated. Green flashes and green rays are optical phenomena that occur shortly after sunset or before sunrise, when a green spot is visible, usually for no more than a second or two, above the sun, or it may resemble a green ray shooting up from the sunset point. Green flashes are a group of phenomena stemming from different causes,[12] most of which occur when there is a temperature inversion (when temperatures increase with altitude rather than the normal decrease in temperature with altitude). Green flashes may be observed from any altitude (even from an aircraft). They usually are seen at an unobstructed horizon, such as over the ocean, but are possible over cloud tops and mountain tops as well. A green flash also may be observed in association with the Moon and bright planets at the horizon, including Venus and Jupiter.[13][14]
The Earth's shadow is the shadow that the Earth itself casts on its atmosphere, which is often visible from the surface of the Earth, as a dark band in the sky near the horizon. This atmospheric phenomenon can sometimes be seen twice a day, around the times of sunset and sunrise. When the weather conditions and the observer's viewing point permit a clear sight of the horizon, the shadow can be seen as a dark blue or greyish-blue band. Assuming the sky is clear, the Earth's shadow is visible in the opposite half of the sky to the sunset or sunrise, and is seen right above the horizon as a dark blue band. A related phenomenon is the "Belt of Venus" or "anti-twilight arch" (sometimes written as "antitwilight arch"), a pink band that is visible above the dark blue of the Earth's shadow, in the same part of the sky. There is no clear dividing line between the Earth's shadow and the Belt of Venus; one colored band shades into the other in the sky.[15][16]
Twilight is divided into three segments according to how far the sun is below the horizon in segments of 6?. After sunset the civil twilight sets in, and ends when the sun drops more than 6? below the horizon. This is followed by the nautical twilight, when the sun reaches heights of -6? and -12?, after which comes the astronomical twilight defined as the period from -12? to -18?. When the sun drops more than 18? below the horizon the sky generally attains its minimum brightness.[17]
Several sources can be identified as the source of the intrinsic brightness of the sky, namely airglow, indirect scattering of sunlight, scattering of starlight, and artificial light pollution.
During the night
The Milky Way can be seen as a large band across the night sky, and is distorted into an arch in this 360? panorama.
Main article: Night sky
The term night sky refers to the sky as seen at night. The term is usually associated with skygazing and astronomy, with reference to views of celestial bodies such as stars, the Moon, and planets that become visible on a clear night after the Sun has set. 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.
The night sky and studies of it have a historical place in both ancient and modern cultures. In the past, for instance, farmers have used the state of the night sky as a calendar to determine when to plant crops. The ancient belief in astrology is generally based on the belief that relationships between heavenly bodies influence or convey information about events on Earth. The scientific study of the night sky and bodies observed within it, meanwhile, takes place in the science of astronomy.
Within visible-light astronomy, the visibility of celestial objects in the night sky is affected by light pollution. The presence of the Moon in the night sky has historically hindered astronomical observation by increasing the amount of ambient lighting. With the advent of artificial light sources, however, light pollution has been a growing problem for viewing the night sky. Special filters and modifications to light fixtures can help to alleviate this problem, but for the best views, both professional and amateur optical astronomers seek viewing sites located far from major urban areas.
Use in weather forecasting......
(woo-hoo) She wasn't expecting it. When he entered you, did you say anything? NO. Did you like it? It was painful..somewhat. Why didn't you tell him no? I eventually did when it became painful. Jodi knew he wanted it. She trusted him. She went with the flow. Did this go on for several minutes? Not to long. The only reason she told him to stop was it was painful. "she had to have him stop or otherwise she would have had him contuine" (her words) Travis finished. He cummed on her back..or somewhere. They kissed and Travis left. How did you feel about yourself?" I didn't feel very good. I felt like a used piece of toilet paper". (her words)
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Originally Posted by Dimple blossom
now we need a recess Hoedi Diary entry Justice11!!!!
