If the universe started out with the big bang, what was before it?
331026
The Big Bang theory itself, doesn't say anything about the *cause* of the explosion. It describes only how the Universe evolved after the explosion took place.\n\nThe reason is twofold.\nFirst of all, the models physicists use to describe the Universe, like General Relativity and Quantum Mechanics break down in the extreme conditions immediately after the initial explosion. However, they do a very good job in describing the existing data afterwards. And with the recent high precision measurements by satellite of the cosmic background that is very impressive.\n\nThe second reason is that GR and QM are only approximations of the correct theory. In fact they give different answers in the region were they overlap. Fortunately this happens only in extreme conditions, close to black holes for instance. And, you guessed it, in the microseconds after the Big Bang.\n\nConclusion: there is therefore a lot of room left to speculate. Not for the scientists though, because there are no data available for these initial moments of the Universe. No data means, nothing to test theories on.
526175
You could start with the Wikipedia entry for the Big Bang.
638759
The question assumes that the matter was compacted, but before the big bang, there was no universe as we understand it, so the idea of "volume" is somewhat meaningless.  What was the sound that came before silence?\n\nPre-BigBang makes your head hurt doesn't it? It does mine!
230650
I think the Big Bang is actually another universe budding off. There were mulitple Universes (Parralel Universe Theory) before the big Bang. Yet, what do u define as a universe? If it is a "world" of intelligent being maybe not (who knows). So the answer is yes and no depending on ur definiton of a universe.
509195
When you look out into space and see 2 galaxies\ngoing in opposite directions you can deduce  \nthat they were closer a year ago and closer yet a million\nyears ago and closer yet a billion years ago. Astronomers\nhave basically looked at countless pairs like this and\nfound that they all were as close as  one point\napproximately 13.8 billion years ago. From that point in\ntime, everything exploded in opposite directions and kept\non getting farther and farther away from the start. So\nthe starting point is called the big bang.\n  What it started with and why  is still conjecture. \nIt has not even reached the level of being called a theory.\nAnd by the way, a scientific theory is not merely a wild guess. It's the best possible, and most widely accepted logical and natural explanation for the evidence.
845326
We cannot say.\n\nAt the moment we only have information from when the big bang happened to like 1 billionth of a second.\n\nWe do not know what was before the Big Bang as the universe is time and space and everything. Anything before there has a negative time which is impossible..
386524
If M-theory is correct, the Big Bang may have been caused by a collision between other universes so you may find other universes (perhaps with differing physics to our own) beyond our universe. Otherwise you would find nothing.
356868
how else would the universe have come into creation?  Before time existed, there must have been nothing, and at the first possible moment of time, there must have been some minute form of matter.  Whether or not the universe was created in a big bang, I cannot know, since if the big bang theory is true (as well as the Big Crunch theory), then it is possible that the universe has already cycled many times.\n\nBeyond that though, the Big Bang theory does NOT say that the size of the initial chunk of matter was infinitessimally small, it just says that it was supercompact.  It was probably insanely large, but relatively small for all the matter it withheld.
524567
First of all, the Big Bang theory does not address how the universe actually got started. It describes how the universe has been since that point. And it is remarkably well established for times after about 1 millisecond after things got started. The universe is expanding and went through a period of very fast expansion early on. The temperature has been decreasing since the start which was about 13.7 billion years ago.\n\nHow things actually got started is *much* more specualtive. There are two main ways that people approach this, but I want to emphasize that neither is actually part of the Big Bang theory and that both are *very* specualtive. We simply don't have the data to figure out what happened before that first millisecond or so.\n\nThe first approach is to point out that time itself is part of the fabric of the universe. It is not something idependent. Part of the nature of the Big Bang in general relativity is that it is a 'singularity'. An analagous thing would be to look at the north pole. This is a singularity in the coordinate system of latitude and longitude. You can't go 'north of the north pole'. In a very similar way, the time coordinate cannot be extended (in this approach) past the Big Bang. This means there is no 'before the Big Bang'. Time simply doesn't make sense at that point.\n\nThe other main approach is to say that the singularity predicted by general relativity doesn't happen because of smoothing out by quantum effects. This *could* allow the time coordinate to extend past the Big Bang (but it doesn't have to). In this scenario, the Big Bang was a quantum fluctuation that 'got out of hand' and underwent exponential growth becoming the universe. The beginning was random since such quantum events are random (this is known and established). However, there would be physical laws describing the probabilities of such things happening. In this approach, there can be multiple universes that don't interact and that have various physical properties different than our own.\n\nI hope this helps!
70981
From all the evidence science has on the subject, the universe began spontaneously as a point source (singularity)of infinite density and energy. At the instant of creation, the temperature of the universe was probably greater than 10e12 Kelvin (1.8e13 Fahrenheit) The best evidence we have today that this is a valid theory (called the "Big Bang") is that all major structures in the universe are rushing away from each other, and the universe today is bathed in the remnants of that initial heat, now cooled down to -454 degrees Fahrenheit.
178557
The Big Bang didn't happen in a place.  Space and time were created in the big bang. The Big Bang is a theory to explain universal/spatial expansion. \n\nI think it's easiest to look at the idea this way. Scientists have observed that everything past our local galactic cluster seems to be retreating from us. All observations point to the universe being infinite and roughly uniform in all directions. \n\nIf it's expanding at given rate now, chances are it's slowed down. Go back in time, the universe was denser and expanding faster. Rewind the timeline far enough and you'll come to a period when everything was all bunched together in a massive, undiscernable clump. Then, suddenly, Bang!!! Space! And everything in it... which has been spreading out and slowing down (pretty much) ever since. \n\nTry thinking about it like the air expaning in bread as it rises, or in a balloon as it fills. Everything is moving apart from everything. Only the universe has been infinitely large from the get go. It's almost like someone just keeps adding empty space in between everything.\n\nIf it helps at all, the center of the big bang for the visible universe was the same place the center of the visible universe always is. Wherever you are. From that point, everything you can see was at some moment in the past gethered together in a lump with infinite density.
341014
You are right!  If the universe were infinitely old, the universe would be very bright.  However, early after the big bang, there was a period called "inflation", during which the early universe expanded much faster than the speed of light-because of this, the majority of object were seperated prior to the universe becomine transparent (when the concentration of hydrogen dropped low enough that light could travel long distances).  Now, the far distant places are traveling away at nearly the speed of light, and there are large dark places which absorb light.
1015241
space-time itself originated in the big bang.  everywhere in the universe was once the big bang, and the whole universe was the big bang.  it is actually a common misconception that the big bang occurred at a specific location.\n\nhttp://www.sciam.com/print_version.cfm?articleID=0009F0CA-C523-1213-852383414B7F0147\nhttp://map.gsfc.nasa.gov/m_uni.html\nhttp://universeadventure.org/
482700
My current belief is that there was time before time as we know it. Something "had" to exist before the cosmos as we now understand it. The Big Bang wasn't the first, nor the last. In order for that to occur, yes, I believe that it was the result of a black hole to end all black holes reaching its limit. It's a thin, untested theory, but it is what I am with until something better is derived. This is consistent with my answer to your later question. That is I haven't thought about the possibility of one universe existing within another. It is plausible in my mind though and interesting enough to think about it for years to come.
279005
The Big Bang Theory is the dominant scientific theory about the origin of the universe. According to the big bang, the universe was created sometime between 10 billion and 20 billion years ago from a cosmic explosion that hurled matter and in all directions. \nIn 1927, the Belgian priest Georges Lemaître was the first to propose that the universe began with the explosion of a primeval atom. His proposal came after observing the red shift in distant nebulas by astronomers to a model of the universe based on relativity. Years later, Edwin Hubble found experimental evidence to help justify Lemaître's theory. He found that distant galaxies in every direction are going away from us with speeds proportional to their distance. \n\nThe big bang was initially suggested because it explains why distant galaxies are traveling away from us at great speeds. The theory also predicts the existence of cosmic background radiation (the glow left over from the explosion itself). The Big Bang Theory received its strongest confirmation when this radiation was discovered in 1964 by Arno Penzias and Robert Wilson, who later won the Nobel Prize for this discovery. \n\nAlthough the Big Bang Theory is widely accepted, it probably will never be proved; consequentially, leaving a number of tough, unanswered questions.
75867
According to the Big Bang Theory, time started during the Big Bang, and since there was no time before the big bang, there is no such thing as "before the big bang".
71447
big bang. and its a big universe, we cant be all alone