Big bang theory is not about the big bang (a misnomer). It is theory on what takes place after the so called bang.( universe expansion )
It doesn't address why or how the expansion starts.
I don't know why you have such a hard time understanding this concept.

Big bang theory is not about the big bang (a misnomer). It is theory on what takes place after the so called bang.( universe expansion )
It doesn't address why or how the expansion starts.
I don't know why you have such a hard time understanding this concept.

I guess if it is not in the book, it doesn`t exist?

I get it now.

eader]Quote from kb2222:

While the scientists do not claim to know the cause of the theorized Big Bang they certainly claim as you point out "what took place milliseconds after" which leads one to wonder how they can "know" what took place milliseconds afterwards when the BB is nothing but a "theory" to begin with? And a theory they can't show is even possible.

Its all just speculation commencing with trying to explain why the universe was observed to be expanding and having the bright idea if its expanding in the past it was smaller, more compact and denser thus they put certain parameters into a computer model and ran it backwards until it ended up with what they call a "singularity" even though that is beyond the known laws of physics. Hence they can't show such a singularity supposedly containing all the energy of the universe in a infinitesimal point is even possible.

How in the hell could it be. It defies even my imagination and it should defy yours, the total energy of the universe is ENORMOUS.[/quotet

The more the advancements of telescopes which peer farther than ever Imagined, the measurements can be more precise.
By what man knows today, being with the rate of speed moving away from an object, distance equated in, from my understanding, it is the distance that makes the difference. But measuring the distance and the speed of light, one is able to get a glimpse of the past and have some understanding of what took place.

To my knowledge, science can peer back as far as 400,000 years after the BBT. That is the measurements of the farthest Galaxy and the speed of light together. I believe the rate of expansion gets figured into this as well. But the key is the rate of expansion and the distance between galaxies, science can get a glimpse of what took place. The more distance there is, the faster it expanded in the beginning, defying the speed of light.

I understand the concept perfectly. What I don't understand is why the two of you continue to conflate the big bang with the expansion of the universe. Decide what you want to talk about and stick with it. I believe in and agree with the inflation and expansion of the universe. more do you want?

The Big Bang Theory is the leading explanation about how the universe began. At its simplest, it talks about the universe as we know it starting with a small singularity, then inflating over the next 13.8 billion years to the cosmos that we know today.Jun 22, 2015

Soon-Coming Scientific Discoveries. Look for these in the near future:
a) Already "big bang" cosmologists postulate space expansion (not just matter expanding into space) to explain how galaxies quickly existed 13+ billion light years from us.
b) Discovery of Atlantis- the First Garden of Eden (<2 years)
c) The Andromeda galaxy is closer than once thought; light from there takes "almost one million years", not more than two million years as is presently believed (<10 years)
d) The forth and last outer space zone (<10 years)
e) Spectrographic reinterpretation of the distance-redshift linear relationship (<10 yrs)
f) Overthrow of "big bang" cosmology; universe is 'smaller than we thought' (<15 years)
g) Discovery of non-breathing, electrically powered humanoids "in close proximity" to Earth - Ganymede, Jupiter's satellite largest in the solar system, is a candidate (Anytime we look for them.)

What produced the energy before inflation? This is perhaps the ultimate question. As crazy as it might seem, the energy may have come out of nothing! The meaning of “nothing” is somewhat ambiguous here. It might be the vacuum in some pre-existing space and time, or it could be nothing at all – that is, all concepts of space and time were created with the universe itself.

Quantum theory, and specifically Heisenberg’s uncertainty principle, provide a natural explanation for how that energy may have come out of nothing. Throughout the universe, particles and antiparticles spontaneously form and quickly annihilate each other without violating the law of energy conservation. These spontaneous births and deaths of so-called “virtual particle” pairs are known as “quantum fluctuations.” Indeed, laboratory experiments have proven that quantum fluctuations occur everywhere, all the time. Virtual particle pairs (such as electrons and positrons) directly affect the energy levels of atoms, and the predicted energy levels disagree with the experimentally measured levels unless quantum fluctuations are taken into account.

Perhaps many quantum fluctuations occurred before the birth of our universe. Most of them quickly disappeared. But one lived sufficiently long and had the right conditions for inflation to have been initiated. Thereafter, the original tiny volume inflated by an enormous factor, and our macroscopic universe was born. The original particle-antiparticle pair (or pairs) may have subsequently annihilated each other – but even if they didn’t, the violation of energy conservation would be minuscule, not large enough to be measurable.

If this admittedly speculative hypothesis is correct, then the answer to the ultimate question is that the universe is the ultimate free lunch! It came from nothing, and its total energy is zero, but it nevertheless has incredible structure and complexity. There could even be many other such universes, spatially distinct from ours.

And in our Milky Way astronomers have found a star that is 5 Billion times the solar volume of our Sun, yes, that's right 5 BILLION times, in which its smallest solar flares would consume our Sun.

The Largest Star: UY Scuti
As it stands, the title of the largest star in the Universe (that we know of) comes down to two contenders. For example, UY Scuti is currently at the top of the list. Located 9.500 light years away in the constellation Scutum, this bright red supergiant and pulsating variable star has an estimated average median radius of 1,708 solar radii – or 2.4 billion km (1.5 billion mi; 15.9 AU), thus giving it a volume 5 billion times that of the Sun.

However, this average estimate includes a margin of error of ± 192 solar radii, which means that it could be as large as 1900 solar radii or as small as 1516. This lower estimate places it beneath stars like as V354 Cephei and VX Sagittarii.

The reason I am posting this is to convey some idea of how much ENERGY-MASS is in the universe and this energy-mass only accounts for 5% of the total energy of the universe. Thus to me it is absolutely absurd to believe the BBT that claims all of this ENORMOUS energy of the universe was 13.8 billion years ago contained within a infinitesimal point of infinite temperature and infinite density smaller than a proton.

And I submit there is absolutely no way these scientists can show that this is even possible.

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{quote]Why is it ludicrous?

To claim the Big Bang happened from a point of infinite temperature, infinite density, infinitesimal in size that is physically indescribable, mathematically unverified, and beyond the conceptions of space and time is nothing but scientific SPECULATION.

No, the possible existence of infinite curvature of spacetime into a singularity is part of Einstein's theories of Relativity, which are mathematically based, so singularities aren't "mathematically unverified", given that they exist in mathematics.

Whether they can exist in reality is another matter. The singularity that may have preceded universe expansion is unverified by direct observation, but hardly pure speculation. The leftover radiation of the CMB was predicted as an expected remnant of this event in the 1940's, and the prediction was borne out when it was discovered in the 1960's. Thus, BBT is supported by more than one line of evidence.

Sure if you put certain parameters into a computer model and run it backwards that's what you apparently come up with but that doesn't make it the truth.

Truth or otherwise, BBT is supported by evidence, and so the theory represents the closest approach to truth that has been made at this time. Certainly closer than the UB model, which isn't supported by all the evidence, and appears as if the UB authors has adopted what was known of universe expansion in the early 20th century and embellished these facts with his own comforting inventions, where, instead of expanding forever in an alarming and ever-accelerating way, the universe acts in an orderly ongoing fashion with God at it's centre in his little pad controlling everything. Like a thermostat.

Do you have any real conceptual knowledge of how BIG the universe is? Our own Milky Way Galaxy has over a hundred billion stars in it and its not even the average size galaxy and the universe has hundreds of billions of galaxies in it and that's one hell of a lot of stars.

Incredulity about the size and content of the universe may not be relevant in view of hypotheses about how the universe may have emerged from nothing, with gravity and energy as opposing forces deriving from nothing in a way analogous to how +1 and -1 can be extracted from zero.

This bite size video explains the idea.

How the universe appeared from nothing

https://www.youtube.com/watch?v=i0BQU0WVG60

Here's a textual exposition:

To postulate a big bang theory based on a backward extrapolation of observed movement of matter (galaxies) when such matter accounts for no more than 4% of the energy of the universe is ludicrous. To claim the Big Bang happened from a point of infinite temperature, infinite density, infinitesimal in size that is physically indescribable, mathematically unverified, and beyond the conceptions of space and time is nothing but scientific SPECULATION.

         

In a galaxy one billion light years away it doesn't seem possible that we could know what its doing right now. How much movement can one detect in say 50 years of observing a galaxy move when it takes a billion years for us to be aware of it? When we look at galaxies that we say are a billion light years away we are seeing the past in the present but I don't equate that as looking back in time.

"If galaxies are all moving apart at ever increasing speed, how can they collide?"

—J. Gow, Fairfax, Va.

Cosmologist Tamara Davis, a research fellow at the University of Queensland in Australia and an associate of the Dark Cosmology Center in Denmark, brings together an answer:

The dynamics of the universe are governed by competing forces whose influence varies with scale, so local forces can override universal forces in discrete regions. On scales larger than galaxy clusters, all galaxies are indeed moving apart at an ever increasing rate. The mutual gravitational attraction between two galaxies at that distance is too small to have a significant effect, so the galaxies more or less follow the general flow of the expansion. But it is a different story in a galaxy's local neighborhood. There the gravitational attraction can be very significant and the interactions much more exciting.

Dark energy, believed to be causing the acceleration of the expansion of the universe, provides a constant outward force that does not dilute as the universe expands. Pitted against this relentless push is the gravitational pull from the rest of the matter and energy in the universe. Early on, the universe was much denser than it is today, and the attractive force of gravity was winning the battle, on scales both large and small. Clouds of gas condensed to form stars and galaxies, and galaxies drew together to form clusters. If there had been more matter around, the universe might have started to recollapse before it ever had the chance to accelerate. But matter and energy do dilute as the volume of the universe increases, so dark energy slowly came to dominate. Since about six billion years ago (about a billion years before Earth formed), the expansion has, on average, been accelerating.

Nevertheless, the cosmic dance continues. Galaxies that had been pulled together before the universe began accelerating still have the chance to collide. Collectively they form overdense patches of the universe in which gravity still reigns. In our neighborhood the Andromeda galaxy, our largest companion, is actually falling toward us, and we will have our first close encounter with it in just a few billion years' time.

Our local group comprises Andromeda, the Magellanic Clouds and about 35 other galaxies, all of which lie in an even larger cluster called Virgo. Together we will travel through the expanding universe, and we had better learn to like the company any galaxies that have not yet won the gravity war have missed their chance. The universe is now split into pockets of interaction that will drift alone through the expanding cosmos.

Like revelers on a ship, the galaxies in our group will continue to collide and interact in myriad interesting ways, but we will be forever separated from the revelers on other ships sailing away from us in the vast universe.

Galactic collisions happen because some galaxies are still close enough to each other for their mutual gravitational attraction to overcome the repulsive force of space expansion.

To postulate a big bang theory based on a backward extrapolation of observed movement of matter (galaxies) when such matter accounts for no more than 4% of the energy of the universe is ludicrous.

*

The article says what I quoted ("formed at roughly the same time") and you didn't answer my question.

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They formed at the same time but evidently were not as close as they are now. Both the Milky Way and Andromeda accreted more material by collisions with other galaxies in the local group, and this process looks set to continue for some time yet. The distant future will probably see a reduction in collisions as local groups under gravitational influence merge into ever larger galaxies but widening distances between galaxies precludes further clumping.

What's your problem, older?

preclude
verb

prevent from happening; make impossible.

Quote from kb2222:
Which would you prefer? A universe acting "in an orderly ongoing fashion with God at it's centre"? Or, one "expanding forever in an alarming and ever-accelerating way"?

You are absolutely correct, scientist have no interest in disproving or proving any gods existence. Science concerns itself with factual, measurable and substantive facts and since there is no measurable evidence available concerning the existence of gods then they (gods of any myth) are a non issue to scientific studies.

You have the right to believe anything you wish.

The problem with singularities explained by a Physics Phd student. The mathematically minded may care to Google the link. There are a couple of equations that won't show up in this post:


http://www.physlink.com/education/askexperts/ae251.cfm

The Extrapolation of the expansion of the universe backwards in time using general relativity yields an infinite density and temperature at a finite time in the past.[14] This singularity indicates that general relativity is not an adequate description of the laws of physics in this regime.

The Big Bang theory, built upon the equations of classical general relativity, indicates a singularity at the origin of cosmic time; this infinite energy density is regarded as impossible in physics.

Today scientists describe the universe in terms of two basic partial theories - the general theory of relativity and quantum mechanics. They are the great intellectual achievements of the first half of this century. The general theory of relativity describes the force of gravity and the large-scale structure of the universe, that is, the structure on scales from only a few miles to as large as a million million million million (1 with twenty-four zeros after it) miles, the size of the observable universe. Quantum mechanics, on the other hand, deals with phenomena on extremely small scales, such as a millionth of a millionth of an inch. Unfortunately, however, these two theories are known to be inconsistent with each other - they cannot both be correct. One of the major endeavors in physics today, and the major theme of this book, is the search for a new theory that will incorporate them both - a quantum theory of gravity. We do not yet have such a theory, and we may still be a long way from having one, but we do already know many of the properties that it must have. And we shall see, in later chapters, that we already know a fair amount about the predications a quantum theory of gravity must make.

Now, if you believe that the universe is not arbitrary, but is governed by definite laws, you ultimately have to combine the partial theories into a complete unified theory that will describe everything in the universe. But there is a fundamental paradox in the search for such a complete unified theory. The ideas about scientific theories outlined above assume we are rational beings who are free to observe the universe as we want and to draw logical deductions from what we see.
In such a scheme it is reasonable to suppose that we might progress ever closer toward the laws that govern our universe. Yet if there really is a complete unified theory, it would also presumably determine our actions. And so the theory itself would determine the outcome of our search for it! And why should it determine that we come to the right conclusions from the evidence? Might it not equally well determine that we draw the wrong conclusion.? Or no conclusion at all?

The only answer that I can give to this problem is based on Darwin’s principle of natural selection. The idea is that in any population of self-reproducing organisms, there will be variations in the genetic material and upbringing that different individuals have. These differences will mean that some individuals are better able than others to draw the right conclusions about the world around them and to act accordingly. These individuals will be more likely to survive and reproduce and so their pattern of behavior and thought will come to dominate. It has certainly been true in the past that what we call intelligence and scientific discovery have conveyed a survival advantage. It is not so clear that this is still the case: our scientific discoveries may well destroy us all, and even if they don’t, a complete unified theory may not make much difference to our chances of survival. However, provided the universe has evolved in a regular way, we might expect that the reasoning abilities that natural selection has given us would be valid also in our search for a complete unified theory, and so would not lead us to the wrong conclusions.

Because the partial theories that we already have are sufficient to make accurate predictions in all but the most extreme situations, the search for the ultimate theory of the universe seems difficult to justify on practical grounds. (It is worth noting, though, that similar arguments could have been used against both relativity and quantum mechanics, and these theories have given us both nuclear energy and the microelectronics revolution!) The discovery of a complete unified theory, therefore, may not aid the survival of our species. It may not even affect our life-style. But ever since the dawn of civilization, people have not been content to see events as unconnected and inexplicable. They have craved an understanding of the underlying order in the world. Today we still yearn to know why we are here and where we came from. Humanity’s deepest desire for knowledge is justification enough for our continuing quest. And our goal is nothing less than a complete description of the universe we live in.
Stephen Hawking ~ A Brief History of Time

Because the partial theories that we already have are sufficient to make accurate predictions in all but the most extreme situations, the search for the ultimate theory of the universe seems difficult to justify on practical grounds. (It is worth noting, though, that similar arguments could have been used against both relativity and quantum mechanics, and these theories have given us both nuclear energy and the microelectronics revolution!) The discovery of a complete unified theory, therefore, may not aid the survival of our species. It may not even affect our life-style. But ever since the dawn of civilization, people have not been content to see events as unconnected and inexplicable. They have craved an understanding of the underlying order in the world. Today we still yearn to know why we are here and where we came from. Humanity’s deepest desire for knowledge is justification enough for our continuing quest. And our goal is nothing less than a complete description of the universe we live in.

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I think religious hypotheses about the importance of the human MIND are best excluded from scientific theories about the workings of the universe, lest the wishful thinking aspects of how our minds work have an adverse effect.

This extract from a letter by Charles Darwin always comes to mind in these cases, although it's best read in full context:

https://www.darwinproject.ac.uk/letter/DCP-LETT-13230.xml

While its logical to assume a expanding universe was once smaller and more dense it is NOT logical (at least to me) that at some initial point it had to be infinitesimally small and infinitely dense. Perhaps there was no BB and the observable universe is like a giant bubble wherein the balanced opposing forces of energy and gravity give rise to cyclic expansion and contraction of the bubble (universe). Why is this not a possible theory with the physicists? Can you say, lordclarance?

I don't see uncertainties about what the form the initial singularity took in a state of nature as a problem for the Big Bang, which from the evidence appears to have happened whatever the case.

The cyclic expansion and contraction idea seems like the UB author's deliberate envisaging of a healthily inhaling and exhaling steady-state universe as a setting for his general comforting and optimistic proposal that the universe is a benign, ordered creation filled with intelligent humanoid beings, each imbued with the conservative work ethic and keen to get ahead in the character building business of "universe ascension". That's why I think human wishful thinking should be excluded from scientific theories. Also (again) there's no evidence for the universe having periodic contraction phases, and I think there would be if they actually happened.