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These types of theories that physicists such as Krauss espouse of a "Universe Coming From Nothing" are quite flawed, as by no means are they talking about nothing! Further, the concepts of particles, mass, and energy are not even well-defined when talking about the universe in general. I wrote a paper on this (excuse the shameless self-promotion), it can be ...


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This is a very broad question but I'll try and answer it. I'll not include any mathematics in my answer. If you would like me to get into technical details then let me know and I'll edit my answer. The idea of multiverses has found resonance in multiple places in theoretical physics but I think Brian Greene's categorization of multiverses is perhaps the must ...


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The way to understand this is as follows. Assume that the early-universe is radiation-dominated, and additionally assume that the early universe is of FLRW type with a single fluid that obeys a barotropic equation of state $p = w \mu$ where: $w = 1/3$ for radiation $w=0$ for dust $w=1$ for a stiff fluid, etc... Now, the Einstein field equations ...


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Really, your confusion is rooted in the fact that the equation you give relating temperature and particle mass assumes that the thing's whose temperature you're predicting is a gas of particular matter that obeys Newtonian mechanics. Light, and really anything in the early universe, decidedly does not obey Newtonian mechanics. There are several ways one ...


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Firstly, string theory is a mathematical hypothesis that is currently speculative. It is a possible candidate for a quantum theory of gravity - a unification of QM with Einstein's theory of gravity - General Relativity. The idea of superstring theory emerged from another theory called supergravity. Supergravity was an attempt at a supersymmetric theory of ...


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Your argument is based upon the idea that all the matter in the universe was created at the moment of the Big Bang. If matter can be created from nothing at the moment of the Big Bang then it does seem reasonable that matter could disappear again, as you say. The trouble is that there is no experimental or theoretical support for the idea that matter was ...



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