# Tag Info

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"Cosmos" is the English cognate of the ancient Greek word which refers to the entirety of existence. It is equivalent to the Latin-derived word "universe;" the only difference between the two is the language of origin.

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Which direction is the next closest universe? Which direction to the nearest unicorn? How many universes can surround ours at a time? We don't know the shape of our universe. Whether it's infinite or finite. Whether it's bound or unbound or whether it's part of a theoretical 4 dimensional multiverse or if 3 dimensions are some kind of natural limit. ...

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So, the presenter explains that two observers who are not moving relative to one another will agree on the meaning of "now". However if one observer is moving, then they will no longer agree, and what one considers to be now will be in the past or future of the other. He observes that a sufficiently distant observer, in another galaxy 100 million light ...

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I'd like to see the notion "parallel universe" restricted to universes similar to each other in some sense. This applies best to the many-worlds interpretation of quantum theory. Two universes in this sense can be almost identical, just different in a couple of quantum states. Two such parallel universes could be interpreted (in the simplest case) as two ...

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What temperature means... Temperature is the measure of the energy of particles. The higher the temperature, the more energized the particles. The more energy particles have the faster they move around. This is the particles' kinetic energy that is rising. As it rises, the particles will begin using up more space. Moving particles need more space. In a ...

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If time started in our Universe at the Big Bang, then in what time dimension (outside of ours) do collisions between Universes occur? In inflationary cosmologies, time did not start at the Big Bang. There are many models, but in at least some of them, there is an "inflating" universe which extends infinitely in past (and possibly future) time, ...

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We don't know. The Multiverse Theory is really just a hypothethis; sure, it makes sense, but it cannot be scientifically proven. We really have no reason to doubt that this is our only universe. Wormholes are just as hypothetical, since they would require infinite energy or negative energy to be created, neither of which we can get. Also, keep in mind that ...

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New objects usually get some preliminary name or number according to one or more naming or numbering conventions (e.g. HR numbers for stars). If there aren't too many objects of interest, they are named by the discoverer(s) (e.g. Hubble volume), an institution (e.g. PANSTARRS), an occasional nickname liked by the public (e.g. black hole), or by a majority in ...

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An exact answer would require a rather specific and mathematical formulation of the multiverse in consideration. As a simple approximating example, suppose we have a countably infinite number of (observable) universes of the same mass $M$. Suppose the dimension of the full multiverse is one higher than each individual universe, and suppose the universes ...

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The answer to your question for brane cosmology is simply that gravity follows the inverse-square law. We don't feel the gravitational pull of, say, Mars because it's so far away. Any other universes are so unimaginably (all right, that's hyperbole) far away in comparison that any gravitational effects by the matter in them would be very, very, very, tiny. ...

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There is no way to know, if any other "different Universe" exists. There is also a terminologic problem with it. Universe means, on latinic, something what "contains everything". If there is no way for the different "Universes" to interact, then how could we know that it exists? If there is a way to interact. For example, there is another spacetime where ...

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First of all it has to be stated that it is difficult to have a scientific discussion about multiple universes. The problem with multiple universes is that it can be logically deducted from assumptions and hypotheses, but not tested nor empirically verified. This makes discussions around this topic, like string theory, highly "religious". There are ...

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You have to take care of the kinds of size you are referring to, and sometimes also the type of infinity you get. This applies not just to multiverses but to a lot of other physical and mathematical objects. The simple answer is that the "size" of the multiverse measures "how many" member universes there are, just as we can talk about the ...

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I don't know whether this is a real paradox. Infinities are tricky :) For example, we don't have just one infinity. Also, our knowledge about the universe is too narrow too understand the system of our universe (or multiverse) and we can only imagine the universes as some balls which are expanding into some other space = multiverse. If multiverse exists, it ...

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All of them. If you sit on Earth then (in the many worlds interpretation) each quantum mechanical observation creates multiple universes, and there is a copy of "you" in each one. So if I were to ask, which universe will I be in tomorrow, the answer is "all of them" (except the ones in which I die) If I go into space, float around and come back I will come ...

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Multiple and parallel universes are a feature of a number of "theories", including most famously (and probably before string theory), the many worlds interpretation of quantum mechanics. The attraction of the many worlds or multiverse ideas is that they offer a ready explanation of why we appear to live in a uiverse that has been "fined tuned" for our ...

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There is no obvious implication to re-assess the large-scale topology of the universe. You can still stereographically project infinity to a point on a sphere, if you need. Implications to the holographic principle aren't immediate, at least. When talking about objects beyond the cosmic horizon, it's a difference, whether we talk about observation or ...

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One instance of "many universes" come from interpretation of quantum mechanics. Quantum mechanics' formalism works surprisingly well, however what it actually means in the real world is not known. There are several interpretations of the formalism. Interpretation means that different ways of looking at the mathematical phenomenon always gives the same ...

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