What caused the Big Bang ? And did our universe come into existence through the big bang b4 any other univers

Answer 1

The Big Bang theory developed from observations of the structure of the universe and from theoretical considerations. Observers determined that most "spiral nebulae" were receding from Earth; but the observers themselves were unaware of the cosmological implications of this fact, or that the supposed nebulae were actually galaxies outside our own Milky Way.[5] Georges Lemaître, a Belgian Roman Catholic priest, independently derived the Friedmann-Lemaître-Robertson-Walker equations from Albert Einstein's equations of general relativity in 1927 and proposed, on the basis of the recession of spiral nebulae, that the universe began as a simple "primeval atom"—what was later called the Big Bang.[6]

Soon after, in 1929, Edwin Hubble provided an observational basis for Lemaître's theory. He discovered that, seen from Earth, light from other galaxies is redshifted proportionally to their distance from Earth. This fact is now known as Hubble's law.[7][8] Given the cosmological principle whereby the universe, when viewed on sufficiently large distance scales, has no preferred directions or preferred places, Hubble's law implied that the universe was expanding, contradicting the infinite and unchanging static universe scenario developed by Einstein.[9]


Artist's depiction of the WMAP satellite gathering data to help scientists understand the Big Bang.This idea allowed for two distinct possibilities. One possibility 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.[10] The other was Lemaître's Big Bang theory, advocated and developed by George Gamow. It was actually Hoyle who coined the name of Lemaître's theory, referring to it sarcastically as "this big bang idea" during a program broadcast on March 28, 1949, by the BBC Third Programme. Hoyle repeated the term in further broadcasts in early 1950, as part of a series of five lectures entitled The Nature of Things. The text of each lecture was published in The Listener a week after the broadcast, the first time that the term "big bang" appeared in print.[11] While Hoyle's "steady state" and Lemaître's "Big Bang" were the two most popular models used to explain Hubble's observations, other ideas were also proposed. Some of these alternatives included the Milne model,[12] Richard Tolman's oscillatory universe,[13] and Fritz Zwicky's tired light hypothesis.[14]

For a while, support was split between the "steady state" and "Big Bang" theories. However, the observational evidence eventually began to favor the latter. The discovery of the cosmic microwave background radiation in 1964 secured its place 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 what happened at the Big Bang and reconciling observations with the basic theory.

Huge advances in Big Bang cosmology were made in the late 1990s and the early 21st century as a result of major advances in telescope technology in combination with large amounts of satellite data such as that from COBE, the Hubble Space Telescope and WMAP. Such data have allowed cosmologists to calculate many of the parameters of the Big Bang to a new level of precision and led to the unexpected discovery that the expansion of the universe appears to be accelerating.


Based on measurements of the expansion of the universe using Type 1a supernovae, measurements of temperature fluctuations in the cosmic microwave background, and measurements of the correlation function of galaxies, the universe has a calculated age of 13.7 ± 0.2 billion years. The agreement of these three independent measurements is considered strong evidence for the so-called ΛCDM model that describes the detailed nature of the contents of the universe.

The early universe was filled homogeneously and isotropically with an incredibly high energy density and concomitantly huge temperatures and pressures. It expanded and cooled, going through phase transitions pertinent to elementary particles.

Approximately 10−35 seconds after the Planck epoch a phase transition caused the universe to experience exponential growth during a period called cosmic inflation. After inflation stopped, the material components of the universe were in the form of a quark-gluon plasma (also including all other particles—and perhaps experimentally produced recently as a quark-gluon liquid [3]) in which the constituent particles were all moving relativistically. As the universe continued growing in size, the temperature dropped. At a certain temperature, by an as-yet-unknown transition called baryogenesis, the quarks and gluons combined into baryons such as protons and neutrons, somehow producing the observed asymmetry between matter and antimatter. Still lower temperatures led to further symmetry breaking phase transitions that put the forces of physics and elementary particles into their present form. Later, some protons and neutrons combined to form the universe's deuterium and helium nuclei in a process called Big Bang nucleosynthesis. As the universe cooled, matter gradually stopped moving relativistically and its rest mass energy density came to gravitationally dominate that of radiation. After about 300,000 years the electrons and nuclei combined into atoms (mostly hydrogen); hence the radiation decoupled from matter and continued through space largely unimpeded. This relic radiation is the cosmic microwave background.

Over time, the slightly denser regions of the nearly uniformly distributed matter gravitationally attracted nearby matter and thus grew even denser, forming gas clouds, stars, galaxies, and the other astronomical structures observable today. The details of this process depend on the amount and type of matter in the universe. The three possible types are known as cold dark matter, hot dark matter, and baryonic matter. The best measurements available (from WMAP) show that the dominant form of matter in the universe is cold dark matter. The other two types of matter make up less than 20% of the matter in the universe.

The universe today appears to be dominated by a mysterious form of energy known as dark energy. Approximately 70% of the total energy density of today's universe is in this form. This dark energy causes the expansion of the universe to deviate from a linear velocity-distance relationship, observed as a faster than expected expansion at very large distances. Dark energy in its simplest formulation takes the form of a cosmological constant term in Einstein's field equations of general relativity, but its composition is unknown and, more generally, the details of its equation of state and relationship with the standard model of particle physics continue to be investigated both observationally and theoretically.

All these observations are encapsulated in the ΛCDM model of cosmology, which is a mathematical model of the Big Bang with six free parameters. Mysteries appear as one looks closer to the beginning, when particle energies were higher than can yet be studied by experiment. There is no compelling physical model for the first 10−33 seconds of the universe, before the phase transition that grand unification theory predicts. At the "first instant", Einstein's theory of gravitation predicts a gravitational singularity where densities become infinite.[15] To resolve this paradox, a theory of quantum gravitation is needed. Understanding this period of the history of the universe is one of the greatest unsolved problems in physics.

As it stands today, the Big Bang is dependent on three assumptions:

The universality of physical laws
The cosmological principle
The Copernican principle
When first developed, these ideas were simply taken as postulates, but today there are efforts underway to test each of them. Tests of the universality of physical laws have found that the largest possible deviation of the fine structure constant over the age of the universe is of order 10-5.[16] The isotropy of the universe that defines the Cosmological Principle has been tested to a level of 10-5 and the universe has been measured to be homogeneous on the largest scales to the 10% level.[17] There are efforts underway to test the Copernican Principle by means of looking at the interaction of galaxy groups and clusters with the CMB through the Sunyaev-Zel'dovich effect to a level of 1% accuracy.[18]

Using these assumptions, combined with Einstein's theory of general relativity, one finds that spacetime should be described by a homogeneous and isotropic metric, which must therefore be a FRW metric. These metrics rely on a coordinate chart or grid being laid down over all spacetime, with which we can specify the location of points (e.g., galaxies, stars...) in the universe. The specific chart used is called a comoving coordinate system, since the grid is designed to expand along with the universe, and so objects that are carried along by the expansion of the universe remain at fixed points on the grid. While their coordinate distance (comoving distance) remains constant, the physical distance between two such comoving points expands proportionally with the scale factor of the universe. See also metric expansion of space.

As the universe can be described by such coordinates, the Big Bang is not an explosion of matter moving outward to fill an empty universe; what is expanding is space itself. It is this expansion that causes the physical distance between two comoving points to increase. Objects that are bound together (such as atoms, people, stars, the solar system, or galaxies) do not expand with spacetime's expansion because the forces that bind them together are strong compared with the Hubble expansion that is pulling them apart.

One can also define a conformal time η, in which case the full spacetime metric takes the form of a static metric multiplied by an overall scale factor. The conformal time coordinate is quite useful since the comoving distance traveled by a light ray is equal to the conformal time interval of the trip. This enables one to understand the causal structure of spacetime. For example, the Big Bang occurred at a finite interval of conformal time η0 to the past. Objects whose comoving distance is greater than cη0 are too far away for light to have had time to travel to us since the Big Bang: therefore we cannot see all of the past universe and there is a past horizon. If the universe is accelerating, then there is only a finite amount of conformal time ηF to the future (though this finite amount of conformal time corresponds to an infinite amount of clock or proper time). Objects located at comoving distances further than cηF can never be reached by a light ray emitted by us today, therefore we cannot influence all of the future universe and there is a future horizon. See also cosmological horizon.

Answer 2

The Big Bang is nothing but a term used to describe the EXPANSION of the Universe. There is nor was there ever anything to explode to kick start the Universe. When you have nothing in the first place you still have nothing. A big bang is a descriptive phrase. To have something to read there is the Theory of Everything available in PDF file available by request at [e-mail]

Answer 3

Considering the expansion of the universe is accelerating, the theory that there are an infinite set of contractions and explosions isn't very solid. Science doesn't concern itself with "before the Big Bang" so much, because we can't get evidence to support any theory. Plus the laws of Physics didn't exist until the big bang.

Answer 4

close your eyes and picture pulling a rabbit out of a hat and not making use of a rabbit, and not making use of a hat and and not making use of a magician. There are countless variations of the vast Bang and that's a stretchable thought that particularly a lot adapts to the evidence so freely it doesnt fairly are watching for something. the main everyday being a finite universe comes from no longer something nowhere and no place. there became right into a quantum fluctuation interior the nothingness turning out to be everythingnes the vast bang violates causality and for this reason rationality, so some dodges proposed are the quantum fluctionation isn't type our universe for this reason television shows like 'sliders' with selection universe. i think of it makes greater experience to declare the universe got here ex deo no longer ex nihilo. If the universe got here from God as a substitute of from no longer something it would not violate causality and could make experience.

Answer 5

The Universe as we know it orginated in a hot super dense state at the begining of time.
It has been expanding ever since.
We can work this out to about 14 billion years ago,the comic microwave background radiation predicted by the big bang has been detected.
What cause the big bang is the unanswer question of science.
If you belive in God then this could provide the answer.
Regards
Ray
London
"Where time begins and ends"

Answer 6

Well, as theory says the pressure on the young star (our sun) caused the Big Bang. Although I do not belive it....

There was so much stuff before the universe that we can't even imagine about...It is alll so mysterious...

Answer 7

Hi One theory has the universe going through an infinite series of explosions and implosions over time. If this is true then we are only one universe in an infinite series.

Answer 8

If I remember right......

The Universe was a big ball of gases and something sparked it and it exploded.... during the explosion different pieces of matter united together making the planets and stars.... these planets and stars combined together to form solar systems (ours is called the milky way) the solar systems are still moving away from where the Universe started