# Tag Info

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To my mind, the Big Bang doesn’t refer to a distinct event but to a cosmogonic theory as a whole, that “predicts” ( should we say “retrodicts”?) many different events of the deep past. For example, there is such established term as “Big Bang nucleosynthesis” that describes an epoch several seconds past the Beginning of Time. The Beginning of Time in the ...

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The main problem with this hypothesis is that Penrose–Hawking singularity theorems state existence of cosmological singularity at the beginning of time, unless (at great matter densities) either some mysterious fields intervene or General Relativity fails at all. Cosmological singularity is a thing definitely distinct from a supernova explosion, whichever ...

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You have to consider entropy to answer this question. The idea of the Boltzamnn brain presupposes an expectation of a universe at thermal equilibrium, or maximally high entropy. In order to create the initial state from which the natural processes you describe (evolution, development etc.) require to operate, the universe has to first start in a state of ...

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When I was in high school I wondered the same thing. According to the Inflation models space time expanded exponentially between $10^{-36}$ and $10^{-32}$ seconds after the Big Bang. According to the theory a piece of space the size of a nucleus expanded to the size of a galaxy (rough order of magnitude, possibly even larger) in that very short time. ...

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So I've done some further research into this question and the result I found is quite surprising. There truly is no set definition. Some cosmologists will tell you (as John Rennie mentioned) to avoid using the term "Big Bang" unless you absolutely have to. However, that is a luxury not afforded to all cosmologists. The more surprising thing is that among ...

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The most likely compound would be the Helium Hydride ion

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Here is a short description of Big Bang: Over the years, proponents of the big bang have tried heroically to change the name. They are dissatisfied with the common, almost vulgar connotation of the name and the fact that it was coined by its greatest adversary. Purists are especially irked that it was also factually incorrect. First, the big ...

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You presume causality, namely that something has to occur to instigate something else (cause and effect). In fact, you presume that there is a well-defined "time". However, our current best theories have problems defining time close to the start of the universe. If there is no clear way to define time then you cannot say that something has to precede ...

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Have a read through Did the Big Bang happen at a point? and the answers to it. The singularity at the Big Bang is the zero time limit of the equation (the FLRW metric) that describes the expansion of the universe. Most physicists believe that this is a mathematical artefact and does not describe what actually happened. It seems likely that some quantum ...

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Black body radiation is a statistical description i.e. it assumes there are enough photons that they are distributed according to Boltzmanns law. At energies high enough for a single photon to equal the total energy of the system this assumption breaks down and the black body description will no longer apply. But by the point the energy has got this high ...

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My view is simpler and observational. Observations say that the current state of the observable universe is expanding: i.e. clusters of galaxies are all receding from our galaxy and from each other. The simplest function to fit this observation is a function that describes an explosion in four dimensional space, which is how the Big Bang came into our ...

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The simple answer is that no, the Big Bang did not happen at a point. Instead it happened everywhere in the universe at the same time. Consequences of this include: The universe doesn't have a centre: the Big Bang didn't happen at a point so there is no central point in the inverse that it is expanding from. The universe isn't expanding into anything: ...

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It is true that FRW metric, if redirected backwards in time, predicts a singularity. However, when the universe's size is comparable to the Planck scale, no one really knows what truly happens. To date there is no successful and consistent theory of quantum gravity, although a lot of partially successful ones exist. String theory, for instance has become ...

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The scenario you are talking about may have taken place as a sort of a "Big bounce". Big bounce is the theory of a cyclic universe implying that the big bang in the past will be followed by a big crunch in the future, followed again by a new big bang and so on. However, currently a future big crunch is considered as less probable because it seems that ...

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