What was the cause of the spontaneous symmetry-breaking in the early universe?
409135
supersymmetry is still hypothetical, so nobody is really sure.  Proof of it has not been found yet.
1174337
Yes.  I think (and I think some scientists have discussed this on public TV) that a universe (either in our dimension, or another) was gradually, then more quickly, collapsing into itself, like a black hole, and that caused the bang, and the cycle repeats itself.  They think this because the universe is expanding; when it reaches its maximum limit (and I don't have any idea what causes that limit, etc.) then it starts to reverse direction, and start collapsing in on itself again, and starts the whole process over again.  In a couple of quintillion years).
697552
See my answer to roughly the same exact question:\n\nhttp://answers.yahoo.com/question/index;_ylt=Alup4mffF.dC.kKLZuPl1_Xsy6IX?qid=20061108093837AAg5ALh\n\n\n-----------\n\nactually, here:\n\nOnly the visible universe started. The rest of it always existed as a consequence of that which we call the Heisenburg Indeterminancy Principle (HIP). A vacuum with 0EV as its vacuum energy (aka: zero-point energy) would be perfectly determinable and a violation of the HIP.\n\nThis initial baseline is known as the inflaton.\n\nImagine a big rubber sheet, infinitely long and wide, and extremely thin. The thing will be vibrating fairly randomly just from the non-zero zeropoint energy. These energy fluctuations propagate as waves. Get enough waves adding up, and you'll get some pretty high crests and valleys. Get a big enough deviation, and you'll stretch the rubber in that immediate area so much that its elasticity will change. This is analgous to a vacuum phase change. In the rubber, the sudden rearrangement of the molecules will be released as heat, in a vacuum phase change, the potential energy is released as a massive swelling of spacetime and particles. It's as though the hill gets so high that the rubber loses a great deal of its elasticity and spreads out hugely because it no longer has the same force pulling it back to itself.\n\nIts presence in the rubber sheet will remain only the size of the original hill. Its internal size however, will be much, MUCH larger. This also extends to the real situation. Within the inflaton, the whole universe, our visible universe is smaller than planck scale. However, internally, we're so big that our universe would literally be spawning nearly infinitely many universes itself. We can't see them because they are sub-planck to us, nor can they see us because we are behind their inflationary wall. Inflation happens at speeds that are superluminal, so causality breaks down at this point. The interesting thing of the wall though is that it perfectly MAINTAINS causality.\n\nLong story short: what we see started, randomly. Where it exists had to ALWAYS exist, it could not have not existed.\n\n-------------\n\nThe inflaton isn't being damped. Quantum wave functions are perfect in that regard -- they aren't ACTUAL waves... or they are waves propagated by lossless particles... or... well... you seem an intelligent gent, I'm sure you realize quantum physics has some non-normal takes on a few things. It's sufficient to say that quantum wave functions are fundamental. The vacuum energy of a vacuum is a constant. In fact, it's possible via quantum tunneling for a vacuum's energy to increase in a small area, and this itself would cause a propagative state change.\n\nLet us say, for example, that the base inflaton has a 10 ^ 100 EV baseline. Our visible universe's particular vacuum state has something significantly lower (I don't recall off the top of my head -- a single cubic centimeter contains enough vacuum energy to boil off earth's oceans though). Let's say 10 ^ 90 EV. Because of the nature of quantum randomness, it is possible for a sub-planck fluctuation to momentarily jump to 10 ^ 110. If that fluctuation then spawned a sub-universe, it's vacuum energy might be 10^100 EV -- the same as the original inflaton, more than the 'parent' universe.\n\nThere, by the way, is your quantum entropy. The average total of all universes' vacuum energies would be fluctuating around a central point in a probablistic manner.
1106396
err the big bang was not really a a collision of matter. All mass and energy in the universe existed at a sigularity, or a dimensionless point. The Big Bang simply expanded and inflated it.
258481
The Big Bang almost CERTAINLY occurred. The cosmic microwave background radiation, expansion of galaxies, and isotropy of the background radiation throughout the universe all seem to indicated that the Big Bang really did occur. The cosmic microwave background radiation is usually the strongest piece of evidence presented by scientists to "prove" the Big Bang. Other than the Big Bang theory there are no really acceptable theories other than those which rely on the metaphysical or religious. For a thorough explanation of why the Big Bang almost certainly did occur, see the following link.
310924
Emerging scientific basis\nSee also: Timeline of cosmology and Timeline of the Big Bang \nThe theoretical scientific exploration of the ultimate fate of the universe became possible with Albert Einstein's 1915 theory of general relativity. General relativity can be employed to describe the universe on the largest possible scale. There are many possible solutions to the equations of general relativity, and each solution implies a possible ultimate fate of the universe. Alexander Friedmann proposed one such solution in 1921. This solution implies that the universe has been expanding from an initial singularity; this is, essentially, the Big Bang.\n\nAn important parameter in fate of the universe theory is the density parameter, Omega (Ω), defined as the average matter density of the universe divided by a critical value of that density. This creates three possible ultimate fates of the universe, depending on whether Ω is equal to, less than, or greater than 1. These are called, respectively, the Flat, Open and Closed universes. These three adjectives refer to the overall geometry of the universe, and not to the local curving of spacetime caused by smaller clumps of mass (for example, galaxies and stars).\n\nObservational evidence was not long in coming. In 1929, Edwin Hubble published his conclusion, based on his observations of Cepheid variable stars in distant galaxies, that the universe was expanding. From then on, the beginning of the universe and its possible end have been the subjects of serious scientific investigation. In 1933, Georges-Henri Lemaître set out a theory that has since come to be called the Big Bang theory of the origin of the universe. In 1948, Fred Hoyle set out his opposing theory of a static universe, called the Steady state theory. These two theories were active contenders until the 1965 discovery, by Arno Penzias and Robert Wilson, of the cosmic microwave background radiation, a fact that is a straightforward prediction of the Big Bang theory, and one that the Steady State theory cannot account for. The Big Bang theory immediately became the most widely held view of the origin of the universe.\n\nWhen Einstein formulated general relativity, he and his contemporaries believed in a static universe. When Einstein found that his equations could easily be solved in such a way as to allow the universe to be expanding now, and to contract in the far future, he added to those equations what he called a cosmological constant whose role was to offset the effect of gravity on the universe as a whole in such a way that the universe would remain static. After Hubble announced his conclusion that the universe was expanding, Einstein wrote that his cosmological constant was his "greatest blunder."\n\nStarting in 1998, observations of supernovae in distant galaxies have been interpreted as consistent with a universe whose rate of expansion is accelerating. Subsequent cosmological theorizing has been designed so as to allow for this possible acceleration, nearly always by invoking dark energy and dark matter. Hence recent theorizing about the ultimate fate of the universe allows for a nonzero cosmological constant.\n\n[edit]\nRole of the shape of the universe\nSee also: Shape of the universe \nThe ultimate fate of the universe depends on its overall shape, and on how much dark energy it contains.\n\n \nThe overall geometry of the universe is determined by whether Ω is less than, equal to, or greater than 1.[edit]\nClosed universe\nIf Ω>1, then the geometry of space is closed like the surface of a sphere. The sum of the angles of a triangle exceeds 180 degrees and there are no parallel lines; all lines eventually meet. The geometry of the universe is, at least on a very large scale, elliptic.\n\nIn a closed universe lacking the repulsive effect of dark energy, gravity eventually stops the expansion of the universe, after which it starts to contract until all matter in the universe collapses to a poi
580755
About the only thing I ever heard that made any sense was that there was another universe. The idea was that you have a big bang, which throws all the matter in the Universe outward from the center. After a while (a LONG while) gravity starts pulling these pieces closer together again and you get what's called the Big Crush, where the whole universe get's squidged up into a tiny, infinitely small point. The theory went on to say, that that spot would explode in a Big Bang and the whole thing would start all over again.
150929
The "big bang" is all about math. But not a zero divided by x math...a little more complex. Two competing theories are Inflation - which states that a sudden switch in the vaccuum state formed a false vaccuum that led to a positive-feedback mechanism of matter creation within a few seconds that happened so quickly that space began to expand faster than the speed of light, blowing apart spacetime into a "flat universe".\n\nThe second is the "ekpyrotic scenario" where two membranes collide in five-dimensional space and cause a huge release of energy that condenses into matter. This one's a bit scary because it also postulates that the collision could happen again at any moment and destroy the universe in a big ball of flame.
331684
A gas cloud needs to reach a critical density profile for it to spontaneously collapse into a fusion ball.\n\nI don't think the big bang has anything to do with the process though.
647430
I have indeed considered this. The problem is scientific observation has not agreed with the concept of random quantum mechanics created all the matter in the universe.\n\nThe problem with this idea is how do you explain massive concentrations of matter like Suns. if you want to say random particles colided together and created the massive volume that is a sun then fine. How long would such a thing take? With all the suns in our Galaxy alone how is that possible especially considering you only have about a billion year window before most of your stars start dieing off their is simply too much matter.\n\nWhat is far more likely is the Big Bang. The reason I say this is because of two critical observations. The fact that distant Galaxy's are moving away from us at a constant rate or what is called red shift. If the Universe was formed by random particles why is their a constant drift from a center point? \n\nThe second point is because of what is called cosmic radiation. The theory put out was if at one time the universe was smaller and hotter then their would be cosmic radiation and space would be about 2-4 Kelvin and that's exactly what we found. If what you are saying is true then the temperature of the universe should be at absolute zero.\n\nIf you wish I could recommend some books on the subject.
1182405
I don't really believe in this God-particle everybody is talking about here....\n\nThe scientific theory is that the Universe started as a fluctuation of the vacuum. Such vacuum fluctuations make appear a small amount of energy, for a small time. This phenomenon is responsible for the existence of forces, that hold the Universe and matter together.\n\nNormally the bigger the energy fluctuation, the smaller the time it is in existence.\n\nNot so the Big Bang. That was a HUGE fluctuation. So big that a lot of energy came to appearance in the form of mass, elementary particles. These particles started expanding, before the vacuum could reclaim the energy.\n\nAnd it is still expanding today. 14 billion years later.
805413
You might be interested in M-theory of the universe. It suggests that the universe, ie the big bang that we see is the result of two higher dimensional membranes touching each other. Other membranes may actually touch and produce other kinds of universes but with physics that might be unstable or unusual
1073548
The Big Bang theory is the most popular one. It is hypothesized that the universe was a collection of dust and other particles forming to one huge mass, until heat and gases formed and pressure from gravity and mass caused it all to erupt in one "big bang" causing everything to project and very high speeds in all directions.\n\nOur world was theorize to have originated through this process. The debris and particles that were projected from the point of origin (now the sun) and locked into its gravitation rotation. The larger mass debris attracted other smaller debris by its gravitational pull to form an even larger mass.\nThis mass growing in size of gases, dust and other particles started to alter by factoring conditions such as distance from the sun and compostion of gases and such. Eventually providing the right conditions and atmosphere to form water which is the basis of life. From that life was made sustainable by the oxygen created by water and plant life... so a billion bunch years later we have our planet earth and the universe we live in surrounded by other planets and stars.\n\nThere are also legends and tales from various religions and cultures that tell the begins of our universe and earth. You'll have to look these up and see.
895712
http://www.sciam.com/print_version.cfm?articleID=0009F0CA-C523-1213-852383414B7F0147\nhttp://universeadventure.org/\nhttp://en.wikipedia.org/wiki/Physical_cosmology\nhttp://www.astro.ucla.edu/~wright/cosmo_01.htm\nhttp://map.gsfc.nasa.gov/m_uni.html\n\nthe cosmic microwave background comes from a time when the universe was about 380 000 years old, and we see it in every direction we look, but the universe was much smaller then.  about 380 000 years after the big bang, the universe had expanded and cooled enuf for electrons to combine with atomic nuclei to form atoms (about 74 percent hydrogen and 26 percent helium).  light was then able to pass unscattered by the free electrons so the universe became transparent.  before this, the universe was much like a heavy fog.  we see this light today stretched to microwave wavelengths.  its spectrum shows a blackbody temperature of 2.7 kelvins.  that is 2.7 degrees centigrade above absolute zero.\n\nanything with a cosmic redshift of 1.7 is far enuf away that the expansion of the universe is carrying it away at light-speed, c.  the red shift of the cmb is 1089 so it seems to be receding at my times c.  redshift has three causes:  1) the rapid recession of a light source, 2) an extremely massive and dense light source, and 3) the stretching of spacetime due to the expansion of the universe.\n\nthe cmb seems to be at least 46 billion light years away, yet the universe is only 13.7 billion years old.
1168282
I read a book about this.  I don't remember the title, but this guy claimed he had it.  He claimed that all atoms are expanding at the same rate.  This is what causes gravity.  More massive objects expand in more space in less time than less massive objects.  \n\nI don't remember the details of the rest of the fields, but they all related to this expansion of atoms.
955092
There is no "first cause," nor reason for the Big Bang.  There is no "reason" for anything that happens in our universe -- things happen because of reactions between matter and energy, and in accordance with natural laws.\n\nYour question actually does a very good job of pointing out what is really the BIGGEST difference between religious people and those who accept the evidence showing no god of any kind...\n\nReligious people seem to always assume there is indeed a reason for something.  You'll see the comments here all the time:  "I know god exists, because I saw a beautiful sunset and that just couldn't happen without a reason!" or "God put us here on earth for a reason!"  \n\nThose of us that accept the evidence that there is no god don't need reasons for everything that happens.  We know that if there's enough hydrogen gas in a large volume of space, and it gets gravitationally purturbed, it will start condensing and eventually form a star.  Planets form in the matter pulled into the protoplanetary disc around the star, and once the star begins fusing hydrogen into helium and any of the planets have atmospheres, you're going to get sunsets.  Any dust or particulate matter in a nitrogen and oxygen atmosphere, along with a little water vapor, makes the sunsets look red along the horizon.  Throw in some clouds to be differentially lit by the sun as you turn away from the sun in your planet's rotation, and you get a beautiful sunset.  It's physics, not the will of god.  There are beautiful sunsets on Mars, Jupiter, Saturn (and other planets), with nobody there to see them -- not because god made a beautiful sunset for anyone to see, but the same physics that give us ours.\n\nThere is no reason for things happening.  The natural universe goes merrily on its way, doing what it does ignorant of the little beings on the small blue planet in our solar system and of their desire to find a reason for everything.  The universe doesn't care about reasons...and neither do I :)\nPeace.
8936
Corresponding to each kind of particle, there is an associated antiparticle with the same mass and spin. Some particles, such as the photon, are identical to their antiparticle; such particles must have no electric charge, but not all charge-neutral particles are of this kind. The laws of nature were thought to be symmetric between particles and antiparticles until CP violation experiments found that time-reversal symmetry is violated in nature. The observed excess of baryons over anti-baryons in the universe is one of the primary unsolved problems in cosmology.