The Big Bang theory developed from observations of the structure of the Universe and from theoretical considerations. In 1912 Vesto Sliphermeasured the first Doppler shift of a "spiral nebula “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 at that time. 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 Friedman’s equations in 1927,
The Big bang expansion is a big mystery how it began what would be its future big bang was
Something called the explosion of the biggest star ever formed in the vast universe as my studies and knowledge on big bang and as per my knowledge the big bang expansion will come to an end in coming next 6.3 billion years from now and I also strongly believe that according to my calculation the milky way galaxy is towards the north east direction of the big bang expansion and the universe is expanding at a rate which I call as dev’s constant that’s
9.4605 / 274 * 10 ^5 Km/sec
Well as I told about the initial expansion speed still the truth behind why expansion started what made the big bang was condensation accompany the initial big bang expansion as yet to be found but According to Newton's law of action-reaction, wouldn't a finite (non-singular) universe at the onset of the big bang experience condensation along with expansion? Could this duality be compatible with the cosmological principle of isotropy and homogeneity, but the nice thing about inflation unless you're trying to test the theory is that it doesn't matter how inhomogeneous things were beforehand, they still end up that way in the end. Based on observations, we can't really say anything useful about the pre-inflation universe, but if the Big Bang hypothesis is right, then it wouldn't have had much time to settle. It seems rather hasty to assume that any of it was in equilibrium.
Well expansion is one factor recent study revealed that the expansions will someday stop as I told it might take place 6.3 billion years from now Universe expanding and matter shrinking is two ways of looking at the same thing. Consider that our unit of distance is a matter of definition. We define the meter based upon how far light travels in a certain fraction of a second. By this definition of distance. The universe is expanding and idealized rigid rods have a fixed length. We could define distance in such a way that space is not expanding, but rigid rods (and the meter) are shrinking.
But the fact is that universe is expanding at 9.4605 / 274 * 10 ^5 Km/sec currently and the rest detail info is given in chapter no 8- Accelerating Speed of big bang expansion
Note : This Theory is the Soul property of Mr. NamDev and subjected to Copyright © law , Unauthorized Publishing is Punishable offence, for more information you can contact the Author
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Once scientists understood that the universe was expanding, they immediately realized that it would have been smaller in the past. At some point in the past, the entire universe would have been a single point. This point, later called the big bang, was the beginning of the universe as we understand it today.
The expanding universe is finite in both time and space. The reason that the universe did not collapse, as Newton's and Einstein's equations said it might, is that it had been expanding from the moment of its creation. The universe is in a constant state of change. The expanding universe, a new idea based on modern physics, laid to rest the paradoxes that troubled astronomers from ancient times until the early 20th Century.
Source :http://goo.gl/c1ZWy4
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The Expanding Universe
| For thousands of years, astronomers wrestled with basic questions about the size
and age of the universe. Does the universe go on forever, or does it have an edge
somewhere? Has it always existed, or did it come to being some time in the past?
In 1929, Edwin Hubble, an astronomer at Caltech, made a critical discovery that
soon led to scientific answers for these questions: he discovered that the universe
is expanding.
The ancient Greeks recognized that it was difficult to imagine what an infinite
universe might look like. But they also wondered that if the universe were finite,
and you stuck out your hand at the edge, where would your hand go? The Greeks' two
problems with the universe represented a paradox - the universe had to be either finite
or infinite, and both alternatives presented problems.
After the rise of modern astronomy, another paradox began to puzzle astronomers. In the
early 1800s, German astronomer Heinrich Olbers argued that the universe must be finite.
If the Universe were infinite and contained stars throughout, Olbers said, then if
you looked in any particular direction, your line-of-sight would eventually fall on the
surface of a star. Although the apparent size of a star in the sky becomes
smaller as the distance to the star increases, the brightness of this smaller
surface remains a constant. Therefore, if the Universe were infinite, the
whole surface of the night sky should be as bright as a star. Obviously, there are dark
areas in the sky, so the universe must be finite.
But, when Isaac Newton discovered the law of gravity, he realized that gravity is always
attractive. Every object in the universe attracts every other object. If the universe
truly were finite, the attractive forces of all the objects in the universe should
have caused the entire universe to collapse on itself. This clearly had not happened,
and so astronomers were presented with a paradox.
When Einstein developed his theory of gravity in the General Theory of
Relativity, he thought he ran into the same problem that Newton did: his equations said
that the universe should be either expanding or collapsing, yet he assumed that the
universe was static. His original solution contained a constant term, called the
cosmological constant, which cancelled the effects of gravity on very large scales,
and led to a static universe. After Hubble discovered that the universe was expanding,
Einstein called the cosmological constant his "greatest blunder."
At around the same time, larger telescopes were being built that were able to
accurately measure the spectra, or the intensity of light as a function of wavelength,
of faint objects. Using these new data, astronomers tried to understand
the plethora of faint, nebulous objects they were observing. Between 1912 and 1922,
astronomer Vesto Slipher at the Lowell Observatory in Arizona discovered that
the spectra of light from many of these objects was systematically shifted to
longer wavelengths, or redshifted. A short time later, other astronomers showed that
these nebulous objects were distant galaxies.
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The Discovery of the Expanding Universe
Meanwhile, other physicists and mathematicians working on Einstein's theory of gravity discovered the equations had some solutions that described an expanding universe. In these solutions, the light coming from distant objects would be redshifted as it traveled through the expanding universe. The redshift would increase with increasing distance to the object.
In 1929 Edwin Hubble, working at the Carnegie Observatories in Pasadena, California, measured the redshifts of a number of distant galaxies. He also measured their relative distances by measuring the apparent brightness of a class of variable stars called Cepheids in each galaxy. When he plotted redshift against relative distance, he found that the redshift of distant galaxies increased as a linear function of their distance. The only explanation for this observation is that the universe was expanding.Once scientists understood that the universe was expanding, they immediately realized that it would have been smaller in the past. At some point in the past, the entire universe would have been a single point. This point, later called the big bang, was the beginning of the universe as we understand it today.
The expanding universe is finite in both time and space. The reason that the universe did not collapse, as Newton's and Einstein's equations said it might, is that it had been expanding from the moment of its creation. The universe is in a constant state of change. The expanding universe, a new idea based on modern physics, laid to rest the paradoxes that troubled astronomers from ancient times until the early 20th Century.
Source :http://goo.gl/c1ZWy4
