Sky

The sky (space)

The sky is the space accessible to the ground observation limited by the horizon.
Sky with the aspect of a Vault or a Hemisphere, reason for which one speaks about " voûte" or of " sphère" céleste.
Because of terrestrial rotation, the whole sky presents an apparent rotatory movement around the Axe of the Earth. It is this movement which makes that the Astre S rise to the is, culminates with the Méridien, and lies down with the western. The period of this movement, called sidereal Day, is of 23 hour S 56 minute S and 4,09 second S.

Why the sky is blue?

It is about a question of Atmosphère. The sunlight is a mixture of all the color of the Arc-en-ciel which penetrates in the atmosphere in the form of specific waves to each color, coming to butt against the Molécule S of air, the water drops and the suspended particles. At the time of these collisions, the molecules of air have the characteristic to diffuse the waves relating to the Violet, the Bleu and the Indigo, which are shorter than the others. The mixture of these colors thus confers on the sky this blue which would be of a major black if there were no atmosphere.

Sky, of day and night

Because of the Sun, the diurnal sky is completely different from the night sky . During the day, the brightness of the Sun exceeds that of the others Celestial body S. The sunlight has a yellowish Couleur white which covers the whole of the spectrum.

The atmosphere of the Earth diffuses the sunlight in all the directions, and more particularly the blue wavelength what gives to the sky its color ( Voir the article: Color of the sky and Diffusion Rayleigh ).

Consequently, the Sun appears yellow to us because the blue part of its spectrum is diffused. Since space, the sun is white. Blue and the yellow constitute complementary colors.

By contrast, the night sky is private sunlight. Consequently, it makes Noir, which allows us to observe thousands of star S scintillate in the sky. The stars are always present during the day (most brilliant are visible using a Télescope), but cannot be seen, because the Sun their fact competition.

The Paradox of Olbers, known as “of the sky of fire”, is an apparent contradiction between the black sky of the night and an infinity of star in an infinite universe.

Sky in the History

the Anciens appeared the sky like Solide and represented it by a figure of man holding with two hands a veil deployed above its head.
the Gaulois were afraid which sky their tomb on the head.
the sky still often is represented decorated zodiacaux signs resulting from the Greek Mythologie and which are related to the beliefs of the Astrologie.

Sky and religion

In some Religion S, the sky is the place where live God X ( Our Father which are with the skies… ), or the Au-delà indicates. In the plural: skies (there is 7 skies among Moslems: to see Miraj).

God is a word inherited Latin deus, him even resulting from an Indo-European root *Dyeus Pitar, “Father brilliant Sky”.
Zeus car also its name of dyeus (god of the sky).
Jupiter means “Father of the skies literally”, of the Indo-European root *Dyeus Lord's Prayer (" god of the ciel").
In the Greek Mythology, Ouranos (in Greek old Οὐρανός, “starry sky, firmament”) is a paramount divinity personifying the Sky. He is the son of Gaïa (the Ground).
Nout is the Egyptian goddess sky.

Expressions

With open sky: in the open air.
Between sky and ground: in the air.
To be with the Seven ième sky: to enjoy a great happiness
To leave no stone unturned: all to implement to achieve a goal.
To fall from the sky: to arrive suddenly and generally by the way.
Sky, my husband! : the aforementioned husband arrives suddenly and generally not by the way…

See too

External bonds

Photograph gallery of sky
Pourquoi the sky is blue?

sky|sky

Beats-smg: Dongus Simple: Sky Zh-yue: 天

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