He said the universe was formed of the primary matter filling cosmic space. The particles of this, apparently, solid matter were in a state of rest but differed from each other in density and mass. Attracted by mutual gravitation, they began to move and form separate condensations. These condensations continued to interact, the bigger condensations attracting the smaller ones in the sphere of their action. Thus were formed large knots of matter. But besides gravitational forces there are forces of mutual repulsion, under the action of which colliding particles bounce away from each other in different directions. The direction that the moving particles were given most frequently became predominant, and a mass of knots of matter began to revolve in one direction round a bigger knot, round a central body-The Sun.
The particles revolving round the Sun represented rings of a meteor shower, which had its own centres of attraction-the nuclei of future planets. Gradually uniting under the force of gravitation all meteors are thus transformed into a system of planets circling round the Sun.
In 1796 Pierre Laplace (1748-1827) advanced a similar hypothesis of the origin of the solar system and other worlds. His hypothesis was that the matter of which the Sun, the planets and their satellites consist was at one time of rarefied of gaseous cloud (nebula), Which was in a state of rotation (the cause of which is unknown). On account of the attraction between the particles, this nebula began to condense in its centre and this led to the formation of the primeval Sun. In the beginning it was enveloped in a nebula revolving evenly round it. The particles nearest to the Sun thus described orbits of lesser radius, while those more distant described orbits of bigger radius in the same span of time. Therefore, the farther away from the centre, and the weaker the gravitation, the greater the centrifugal force became. At a certain distance from the centre these forces struck a balance. The boundary separating the given system from the others passed throughthis point.
Giving away its heat into space, the revolving nebula gradually cooled down aqnd, consequently, contracted. That led to an increase of the velocity of rotation, which at length attained a value at which the centrifugal force exceeded the inward pull of gravity. On account of this, the nebula began to lose its spherical form and to change into a more and more pronounced spheroid. Round its equator the nebula began to disintegrate into several narrow and thin rings. Under the influence of uneven cooling, the rings broke off and, owing to the attraction between the particles, the planets revolving round the Sun were formed.
In contrast to Kant's hypothesis, which drew no attention, Laplace's propositions became very popular as soon as they were published, and they influenced the development of astronomy in the nineteenth century. Laplace's hypothesis explained why the planets revolved round the Sun in the same direction as the Sun was rotating round its own axis, why their orbits were arranged nearly in the same plane, why they were rotating round their axis in the same direction as Sun, and so on.
At present the hypothesis of Kant and Laplace, whose content is very nearly the same, are known as the Kant-Laplace hypothesis.
Further study of the universe and the solar system revealed numerous facts that contradicted the Kant-Laplace propositions. It became known, for example, that the satellites of some planets do not rotate in the same direction as the planets themselves (this concerns some of the satellites of Uranus and Jupiter).
Other cosmogonical hypothesis (the hypotheses of Moulton, Chamberlin, Jeans and others) developed out of the Kant-Laplace hypothesis in the twentieth century.
In the past few decades the Soviet scientists who have been developing cosmogonical hypotheses have introduced essential corrections into the scientific ideas advanced in the nineteenth and early twentieth centuries. One of them, Otto Schmidt, believed the early hypotheses were untenable because they were only qualitative. Modern cosmogony, he said, should also engage in quantitative study based on mathematical and statistical methods.
In 1944 Schmidt put forward a new hypothesis in which it was assumed that the planets of the solar system originated from a gas -dust nebula attracted by the Sun as it moved in interstellar space.
The solid meteorite particles revolving round the Sun united under the influence of gravitation and gave rise to the planets. This process of unification of the planets proceeded rather intensively so long as the meteor shower was dense, but in the last 2,000 million years the addition of meteorite to the Earth has been very inconsiderable. The redistribution of the meteorite mass within the Earth proceeded only in a viscous-plastic state without transition through a fluid stage. The Earth, according to Schmidt, was never hot, its average temperature never exceeding 4 degree. The subsequent heating of the Earth is associated with the decay of radioactive elements.
Schmidt's hypothesis plausibly explains all the structural features of the solar system: the circular orbits, the revolution of the planets, the laws governing the scaping of the planets, the division of the planets into two groups (large planets and planets of the terrestrial type); moreover, on the assumption that planets received their quantity of motion from without during the capture of a gas-dust cloud, at the expense of the enormous momentum of rotation of the Galaxy, it solves the major problem of the distribution of mass and momentum in the solar system.
In 1957 the American theoretical physicist John Wheeler coined his term Wormhole. In physics, a wormhole is a hypothetical topological feature of spacetime that is basically a 'shortcut' through space and time. Spacetime can be viewed as a 2D surface, and when 'folded' over, a wormhole bridge can be formed. A wormhole has at least two mouths which are connected to a single throat or tube. If the wormhole is traversable, matter can 'travel' from one mouth to the other by passing through the throat. While there is no observational evidence for wormholes, spacetimes-containing wormholes are known to be valid solutions in general relativity.
However, the idea of wormholes was invented already in 1921 by the German mathematician Hermann Weyl in connection with his analysis of mass in terms of electromagnetic field energy.
The name "wormhole" comes from an analogy used to explain the phenomenon. If a worm is travelling over the skin of an apple, then the worm could take a shortcut to the opposite side of the apple's skin by burrowing through its center, rather than travelling the entire distance around, just as a wormhole traveler could take a shortcut to the opposite side of the universe through a topologically nontrivial tunnel.
The basic notion of an intra-universe wormhole is that it is a compact region of spacetime whose boundary is topologically trivial but whose interior is not simply connected. Formalizing this idea leads to definitions such as the following, taken from Matt Visser's Lorentzian Wormholes.
If a Minkowski spacetime contains a compact region Ω, and if the topology of Ω is of the form Ω ~ R x Σ, where Σ is a three-manifold of nontrivial topology, whose boundary has topology of the form dΣ ~ S2, and if, furthermore, the hypersurfaces Σ are all spacelike, then the region Ω contains a quasipermanent intra-universe wormhole.
Characterizing inter-universe wormholes is more difficult. For example, one can imagine a 'baby' universe connected to its 'parent' by a narrow 'umbilicus'. One might like to regard the umbilicus as the throat of a wormhole, but the space time is simply connected.
It is known that (Lorentzian) wormholes are not excluded within the framework of general relativity, but the physical plausibility of these solutions is uncertain. It is also unknown whether a theory of quantum gravity, merging general relativity with quantum mechanics, would still allow them. Most known solutions of general relativity which allow for traversable wormholes require the existence of exotic matter, a theoretical substance which has negative energy density. However, it has not been mathematically proven that this is an absolute requirement for traversable wormholes, nor has it been established that exotic matter cannot exist.
Despite its interior being invisible, a black hole may reveal its presence through an interaction with matter that lies in orbit outside its event horizon. For example, a black hole may be perceived by tracking the movement of a group of stars that orbit its center. Alternatively, one may observe gas (from a nearby star, for instance) that has been drawn into the black hole. The gas spirals inward, heating up to very high temperatures and emitting large amounts of radiation that can be detected from earthbound and earth-orbiting telescopes. Such observations have resulted in the general scientific consensus that—barring a breakdown in our understanding of nature—black holes do exist in our universe.
The idea of an object with gravity strong enough to prevent light from escaping was proposed in 1783 by the Reverend John Michell an amateur British astronomer. In 1795, Pierre-Simon Laplace, a French physicist independently came to the same conclusion. Black holes, as currently understood, are described by the general theory of relativity. This theory predicts that when a large enough amount of mass is present in a sufficiently small region of space, all paths through space are warped inwards towards the center of the volume, preventing all matter and radiation within it from escaping.
While general relativity describes a black hole as a region of empty space with a pointlike singularity at the center and an event horizon at the outer edge, the description changes when the effects of quantum mechanics are taken into account. Research on this subject indicates that, rather than holding captured matter forever, black holes may slowly leak a form of thermal energy called Hawking radiation. However, the final, correct description of black holes, requiring a theory of quantum gravity, is unknown.
The term black hole to describe this phenomenon dates from the mid-1960s, though its precise origins are unclear. Physicist John Wheeler is widely credited with coining it in his 1967 public lecture Our Universe: the Known and Unknown, as an alternative to the more cumbersome "gravitationally completely collapsed star". However, Wheeler himself insisted that the term had actually been coined by someone else at the conference and adopted by him as a useful shorthand. The term was also cited in a 1964 letter by Anne Ewing to the AAAS.
According to Einstein’s general theory of relativity, as mass is added to a degenerate star a sudden collapse will take place and the intense gravitational field of the star will close in on itself. Such a star then forms a "black hole" in the universe.
The phrase had already entered the language years earlier as the Black Hole of Calcutta incident of 1756 in which 146 Europeans were locked up overnight in punishment cell of barracks at
Popular accounts commonly try to explain the black hole phenomenon by using the concept of escape velocity, the speed needed for a vessel starting at the surface of a massive object to completely clear the object's gravitational field. It follows from
Two concepts introduced by Albert Einstein are needed to explain the phenomenon. The first is that time and space are not two independent concepts, but are interrelated forming a single continuum, spacetime. This continuum has some special properties. An object is not free to move around spacetime at will, instead it must always move forwards in time, and not only must an object move forwards in time, it also cannot change its position faster than the speed of light. This is the main result of the theory of special relativity.
The second concept is the base of general relativity: mass deforms the structure of this spacetime. The effect of a mass on spacetime can informally be described as tilting the direction of time towards the mass. As a result, objects tend to move towards masses. This is experienced as gravity. This tilting effect becomes more pronounced as the distance to the mass becomes smaller. At some point close to the mass the tilting becomes so strong that all the possible paths an object can take lead towards the mass. This implies that any object that crosses this point can no longer get further away from the mass, not even using powered flight. This point is called the event horizon.
The Big Bang is the cosmological model of the universe that is best supported by all lines of scientific evidence and observation. The essential idea is that the universe has expanded from a primordial hot and dense initial condition at some finite time in the past and continues to expand to this day. Georges Lemaître proposed what became known as the Big Bang theory of the origin of the Universe, although he called it his 'hypothesis of the primeval atom'. The framework for the model relies on Albert Einstein's General Relativity as formulated by Alexander Friedmann. After Edwin Hubble discovered in 1929 that the distances to far away galaxies were generally proportional to their redshifts, this observation was taken to indicate that all very distant galaxies and clusters have an apparent velocity directly away from our vantage point. The farther away, the higher the apparent velocity. If the distance between galaxy clusters is increasing today, everything must have been closer together in the past. This idea has been considered in detail back in time to extreme densities and temperatures, and large particle accelerators have been built to experiment on and test such conditions, resulting in significant confirmation of the theory. But these accelerators can only probe so far into such high energy regimes. Without any evidence associated with the earliest instant of the expansion, the Big Bang theory cannot and does not provide any explanation for such an initial condition, rather explaining the general evolution of the universe since that instant. The observed abundances of the light elements throughout the cosmos closely match the calculated predictions for the formation of these elements from nuclear processes in the rapidly expanding and cooling first minutes of the universe, as logically and quantitatively detailed according to Big Bang nucleosynthesis.
Fred Hoyle is credited with coining the phrase 'Big Bang' during a 1949 radio broadcast, as a derisive reference to a theory he did not subscribe to. Hoyle later helped considerably in the effort to figure out the nuclear pathway for building certain heavier elements from lighter ones. After the discovery of the cosmic microwave background radiation in 1964, and especially when its collective frequencies sketched out a blackbody curve, most scientists were fairly convinced by the evidence that some Big Bang scenario must have occurred.
The Big Bang theory developed from observations of the structure of the universe and from theoretical considerations. In 1912 Vesto Slipher measured the first Doppler shift of a "spiral nebula" (spiral nebula is the obsolete term for spiral galaxies), and soon discovered that almost all such nebulae were receding from Earth. He did not grasp the cosmological implications of this fact, and indeed at the time it was highly controversial whether or not these nebulae were "island universes" outside our Milky Way. Ten years later, Alexander Friedmann, a Russian cosmologist and mathematician, derived the Friedmann equations from Albert Einstein's equations of general relativity, showing that the universe might be expanding in contrast to the static universe model advocated by Einstein. In 1924, Edwin Hubble's measurement of the great distance to the nearest spiral nebulae showed that these systems were indeed other galaxies. Independently deriving Friedmann's equations in 1927, Georges Lemaître, a Belgian physicist and Roman Catholic priest, predicted that the recession of the nebulae was due to the expansion of the universe.
In 1931 Lemaître went further and suggested that the evident expansion in forward time required that the universe contracted backwards in time, and would continue to do so until it could contract no further, bringing all the mass of the universe into a single point, a "primeval atom", at a point in time before which time and space did not exist. As such, at this point, the fabric of time and space had not yet come into existence. This perhaps echoed previous speculations about the cosmic egg origin of the universe.
Starting in 1924, Hubble painstakingly developed a series of distance indicators, the forerunner of the cosmic distance ladder, using the 100-inch (2,500 mm) Hooker telescope at Mount Wilson Observatory. This allowed him to estimate distances to galaxies whose redshifts had already been measured, mostly by Slipher. In 1929, Hubble discovered a correlation between distance and recession velocity—now known as Hubble's law. Lemaître had already shown that this was expected, given the Cosmological Principle.
During the 1930's other ideas were proposed as non-standard cosmologies to explain Hubble's observations, including the Milne model, the oscillatory universe (originally suggested by Friedmann, but advocated by Einstein and Richard Tolman) and Fritz Zwicky's tired light hypothesis.After World War II, two distinct possibilities emerged. One was Fred Hoyle's steady state model, whereby new matter would be created as the universe seemed to expand. In this model, the universe is roughly the same at any point in time. The other was Lemaître's Big Bang theory, advocated and developed by George Gamow, who introduced big bang nucleosynthesis and whose associates, Ralph Alpher and Robert Herman, predicted the cosmic microwave background radiation. Ironically, it was Hoyle who coined the phrase that came to be applied to Lemaître's theory, referring to it derisively as "this big bang idea" during a BBC Radio broadcast in March 1949. For a while, support was split between these two theories. Eventually, the observational evidence, most notably from radio source counts, began to favor the latter. The discovery and confirmation of the cosmic microwave background radiation in 1964 secured the Big Bang as the best theory of the origin and evolution of the cosmos. Much of the current work in cosmology includes understanding how galaxies form in the context of the Big Bang, understanding the physics of the universe at earlier and earlier times, and reconciling observations with the basic theory.
Huge strides in Big Bang cosmology have been made since the late 1990s as a result of major advances in telescope technology as well as the analysis of copious data from satellites such as COBE, the Hubble Space Telescope and WMAP. Cosmologists now have fairly precise measurement of many of the parameters of the Big Bang model, and have made the unexpected discovery that the expansion of the universe appears to be accelerating.
Al Baqarah (2) : 29
29. It is He Who hath created for you all things that are on earth; Moreover His design comprehended the heavens, for He gave order and perfection to the seven firmaments; and of all things He hath perfect knowledge.
As Sajdah (32) : 4-64. It is Allah Who has created the heavens and the earth, and all between them, in six Periods, and is firmly established on the Throne (of Authority): ye have none, besides Him, to protect or intercede (for you): will ye not then receive admonition?
5. He rules (all) affairs from the heavens to the earth: in the end will (all affairs) go up to Him, on a Day, the space whereof will be (as) a thousand years of your reckoning.
6. Such is He, the Knower of all things, hidden and open, the Exalted (in power), the Merciful;-
Fushshilat (41) : 9-12
9. Say: Is it that ye deny Him Who created the earth in two Periods? And do ye join equals with Him? He is the Lord of (all) the Worlds.
10. He set on the (earth), mountains standing firm, high above it, and bestowed blessings on the earth, and measure therein all things to give them nourishment in due proportion, in four Periods, in accordance with (the needs of) those who seek (Sustenance).
11. Moreover He comprehended in His design the sky, and it had been (as) smoke: He said to it and to the earth: "Come ye together, willingly or unwillingly." They said: "We do come (together), in willing obedience."
12. So He completed them as seven firmaments in two Periods, and He assigned to each heaven its duty and command. And We adorned the lower heaven with lights, and (provided it) with guard. Such is the Decree of (Him) the Exalted in Might, Full of Knowledge.
An Naazi'aat (79) :27-30
27. What! Are ye the more difficult to create or the heaven (above)? ((Allah)) hath constructed it:
28. On high hath He raised its canopy, and He hath given it order and perfection.
29. Its night doth He endow with darkness, and its splendour doth He bring out (with light).
30. And the earth, moreover, hath He extended (to a wide expanse);
30. Do not the Unbelievers see that the heavens and the earth were joined together (as one unit of creation), before we clove them asunder? We made from water every living thing. Will they not then believe?
31. And We have set on the earth mountains standing firm, lest it should shake with them, and We have made therein broad highways (between mountains) for them to pass through: that they may receive Guidance.
32. And We have made the heavens as a canopy well guarded: yet do they turn away from the Signs which these things (point to)!
33. It is He Who created the Night and the Day, and the sun and the moon: all (the celestial bodies) swim along, each in its rounded course.
Ath Thalaaq (65) : 12
12. Allah is He Who created seven Firmaments and of the earth a similar number. Through the midst of them (all) descends His Command: that ye may know that Allah has power over all things, and that Allah comprehends, all things in (His) Knowledge.
Al A'raaf (7) : 54
54. Your Guardian-Lord is Allah, Who created the heavens and the earth in six Periods, and is firmly established on the throne (of authority): He draweth the night as a veil o'er the day, each seeking the other in rapid succession: He created the sun, the moon, and the stars, (all) governed by laws under His command. Is it not His to create and to govern? Blessed be Allah, the Cherisher and Sustainer of the worlds!
If we saw the above composition of articles then could be concluded that the process of the earth incident and sky (the universe), that the earth beforehand the realisation, afterwards in the further process was followed by the stabilisation of the sky incident that had a position on the earth.
