The sky has to be a symbol of peace. However, there is sky where combat planes are flying when children look up. That is very sad. I wish there would be no more conflict on the Earth. I hope that children all over the world will hold onto their dreams towards the sky. I pray to the infinite sky for world peace.
True love is never lost - but how much loss can it endure? Iris confronts the complexities of family and prejudice in this exquisite and searing debut novel.Just two months after her mother abandons her family, leaving her gruff, introverted father to raise two children alone, Iris watches a family of gypsies set up an illegal camp in the paddock by her house. The gypsy boy, Trick, is restless and warm and full of life - he'll settle when he's in his grave, he tells Iris - and she feels as though she understands him completely. Yet even as Iris's secret friendship with Trick blooms into something more, tensions run high between their families. Iris's father is bent on evicting the travelers, and her beloved brother Sam is impulsive, lost, and headed for trouble. But Trick might not be everything he seems, and as Iris struggles to find where her loyalties lie, all of the prejudice, vulnerability, and anger that surrounds her collides in an unspeakable tragedy. Like love, and like sorrow, the blue summer sky is infinite in this coming-of-age story that is both breathtaking and heartbreaking.
Infinite Sky
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Olbers's paradox, also known as the dark night sky paradox, is an argument in astrophysics and physical cosmology that says that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. In the hypothetical case that the universe is static, homogeneous at a large scale, and populated by an infinite number of stars, any line of sight from Earth must end at the surface of a star and hence the night sky should be completely illuminated and very bright. This contradicts the observed darkness and non-uniformity of the night.[1]
The first one to address the problem of an infinite number of stars and the resulting heat in the Cosmos was Cosmas Indicopleustes, a 6th-century Greek monk from Alexandria, who states in his Topographia Christiana: "The crystal-made sky sustains the heat of the Sun, the moon, and the infinite number of stars; otherwise, it would have been full of fire, and it could melt or set on fire."[2]
Edward Robert Harrison's Darkness at Night: A Riddle of the Universe (1987) gives an account of the dark night sky paradox, seen as a problem in the history of science. According to Harrison, the first to conceive of anything like the paradox was Thomas Digges, who was also the first to expound the Copernican system in English and also postulated an infinite universe with infinitely many stars.[3] Kepler also posed the problem in 1610, and the paradox took its mature form in the 18th-century work of Halley and Cheseaux.[4] The paradox is commonly attributed to the German amateur astronomer Heinrich Wilhelm Olbers, who described it in 1823, but Harrison shows convincingly that Olbers was far from the first to pose the problem, nor was his thinking about it particularly valuable. Harrison argues that the first to set out a satisfactory resolution of the paradox was Lord Kelvin, in a little known 1901 paper,[5] and that Edgar Allan Poe's essay Eureka (1848) curiously anticipated some qualitative aspects of Kelvin's argument:[1]
Thus each shell of a given thickness will produce the same net amount of light regardless of how far away it is. That is, the light of each shell adds to the total amount. Thus the more shells, the more light; and with infinitely many shells, there would be a bright night sky.
Kepler saw this as an argument for a finite observable universe, or at least for a finite number of stars. In general relativity theory, it is still possible for the paradox to hold in a finite universe:[7] Though the sky would not be infinitely bright, every point in the sky would still be like the surface of a star.
The poet Edgar Allan Poe suggested that the finite size of the observable universe resolves the apparent paradox.[8] More specifically, because the universe is finitely old and the speed of light is finite, only finitely many stars can be observed from Earth (although the whole universe can be infinite in space).[9] The density of stars within this finite volume is sufficiently low that any line of sight from Earth is unlikely to reach a star.
The redshift hypothesised in the Big Bang model would by itself explain the darkness of the night sky even if the universe were infinitely old. In the Steady state theory the universe is infinitely old and uniform in time as well as space. There is no Big Bang in this model, but there are stars and quasars at arbitrarily great distances. The expansion of the universe causes the light from these distant stars and quasars to redshift, so that the total light flux from the sky remains finite. Thus the observed radiation density (the sky brightness of extragalactic background light) can be independent of finiteness of the universe. Mathematically, the total electromagnetic energy density (radiation energy density) in thermodynamic equilibrium from Planck's law is
Stars have a finite age and a finite power, thereby implying that each star has a finite impact on a sky's light field density. Edgar Allan Poe suggested that this idea could provide a resolution to Olbers's paradox; a related theory was also proposed by Jean-Philippe de Cheseaux. However, stars are continually being born as well as dying. As long as the density of stars throughout the universe remains constant, regardless of whether the universe itself has a finite or infinite age, there would be infinitely many other stars in the same angular direction, with an infinite total impact. So the finite age of the stars does not explain the paradox.[15]
As if god themself had not given us the ability to look away from the ground and up at the infinite sky and wonderHow many starsHow many worldsHow many ways of being alive? 2ff7e9595c
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