What is Multiverse: Definition and 198 Discussions

The multiverse is a hypothetical group of multiple universes. Together, these universes comprise everything that exists: the entirety of space, time, matter, energy, information, and the physical laws and constants that describe them. The different universes within the multiverse are called "parallel universes", "other universes", "alternate universes", or "many worlds".

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  1. S

    A Multiverse theory with impossible universes?

    I found an article written by physicist George Ellis that confused me a little. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.498.4569&rep=rep1&type=pdf At some part, he says: 3.2 Non-uniqueness: Possibilities There is non-uniqueness at both steps. Stating “all that is possible...
  2. Spinnor

    I Speed limit c in the multiverse

    Do we know enough of the workings of string theory to say what factors give rise to a large or small value of the velocity of propagation of massless fields for a given multiverse? Thanks!
  3. platosuniverse

    B Doesn't there have to be more than one observable universe?

    I was just curious because if space can expand faster than light, doesn't that mean there will be a lot of space that we just can't see? Do objects just vanish because we can't see them? For instance, if a hypothetical alien lived in MACS0647-JD galaxy which is 13.3 billion light years away...
  4. bland

    I Does the concept of infinite parallel universes justify absurdities?

    I know this has been discussed ad infinitum (pun intended) however I have recently been informed by Max Tegmark's book Our Mathematical Universe, that apparently the multiverse concept is becoming mainstream. In fact he mentioned at a recent quantum conference that a show of hands revealed no...
  5. A

    A Multiverse reduction in the new Hawking/Hertog model?

    Hawking and Hertog's new paper "A Smooth Exit from Eternal Inflation?" does away with the infinite multiverse of Hawking's previous theory and proposes a cosmology that predicts "a simpler and finite universe". But I can't figure out the extent of this reduction to a "simpler and finite"...
  6. J

    I Where are the Constants of Nature stored in Multiverse?

    In Multiverses where there are different constants of nature such as the mass of the electron or the value of the strong coupling constants. Where are the values stored? If there were no compactified calabi-yau manifolds that produced the values and they were just like that. What maintains the...
  7. nomadreid

    I Inter-Bubble Connections in Inflationary Multiverse Models?

    I know this is getting into the highly speculative, but given the mathematics that has been done on versions of these concepts that are not known to be inconsistent: In the inflation concept which leads to a multiverse of the "bubble universes" type, in which the laws governing the space-time...
  8. S

    B Why does the multiverse theory have only 4 levels?

    Why does max tegmark's and brian greene's levels of multiverses consider as the highest level the mathematical multiverse hypothesis if other authors like David Lewis consider that there could be also universes non described by maths? Why does it stop at level iv (mathematical universes...
  9. S

    B Does the multiverse really include ALL outcomes?

    In multiverse theory, where it is supposed to describe ALL outcomes, a mathematical multiverse is the ultimate ensemble and there are not more levels than this, but it doesn't contain all the imaginable universes because, as Max Tegmark himseld quoted in a paper "the mathematical universe...
  10. S

    B Can energy change physical laws?

    Could huge amounts of energy change the universe's nature (fundamental physical constants, laws, dimension)? Could it change it so much that it would enable our universe to be a multiverse of level 1, 2, 3 or 4? https://en.wikipedia.org/wiki/Multiverse
  11. andrewkirk

    I MUST every possible thing happen in a Tegmark L1 Multiverse?

    I've been looking at one of Max Tegmark's articles about his 'Mathematical Universe' hypothesis, here on arXiv. As a preliminary, note that Tegmark's framework has four 'levels' of multiverses, with each level being an infinite collection of multiverses at the level below it. The second or...
  12. P

    I Some questions about time and causality in the MWI

    Forgive my novice question; but, how does one explain the fact that decoherence doesn't contradict the evolution of the wavefunction in every world? Meaning, how is causality preserved in each world and what concept of time is professed wrt. to each world in the MWI? In other words, it seems...
  13. S

    I Could vacuum decay save multiverse ideas?

    If we discovered that physical laws could not have been otherwise in our universe as a result of the big bang multiverse ideas would be dead "nature could not have been otherwise, and with a fundamental theory we will be able to prove this" If this was true, would exist any possible way of...
  14. L

    I Paul Steinhardt's cyclic model

    Hello. I think I don't understand very well the Paul Steinhardt's cyclic model of Universe(s). According to Paul Steinhardt, 2 universes get closer. Then, there's the big bounce, which products effects like a big bang. If 2 universes get closer, they have a (relative) speed ( speed is the...
  15. Lunct

    B Quantum Mechanics & Parallel Universes: No-Cloning Rule

    So if there are a near infinite number of parallel universes, many people say that one can exist in multiple universes because there are so many one of them is bound to have a copy of you in it. Would the no-cloning rule of quantum mechanics apply here? If there was an exact copy (all the...
  16. FallenApple

    I Countable or Uncountable Cardinality of Multiverse?

    In the MWI, are the number of universes in the multiverse countable or uncountable? It seems like if all possibilities happen, then that is like the power set, which has uncountable cardinality. Or maybe a Cantor diagonalization argument can be used on the discrete sequence of events over the...
  17. Lunct

    B Is Our Observable Universe the Actual Size of Our Universe?

    In the multiverse theory, I keep on hearing that our observable universe is one of many universes. Is that saying that our universe ends at the point we can no longer see it - at the end of the observable universe. That would mean that the Earth is the literal centre of our universe. Am I...
  18. S

    Butterfly Effect: How much can you do before change occurs?

    I didn't know where to put this, but sci-fi seemed fitting: Just a hypothetical regarding the Butterfly Effect that's been puzzling me, if anyone has any insight... How much could you do in the past before your very presence started affecting history? For fun, let’s say you wake up 12 years...
  19. D

    I Is it possible to travel between the multiverses?

    Do you believe it's possible to travel between our world within a different multiverse? If so, how do you believe it happens/is possible (e.g. Will we invent specialized machines or are there certain points/places that act as portals?)
  20. E

    B How do you build a quantum suicide machine?

    Hey! I posted this thread hoping that there are experts about quantum physics here. Please if you do not know a lot about the subject, don't answer this question: First things first, to be clear: I’m NOT building a quantum suicide machine and I’m NOT trying to kill myself. I’m just curious...
  21. K

    I Is the multiverse fake physics?

    woit over at his blog not even wrong considers string theory based multiverse to be fake physics. he cites sean carroll as others on his blog as examples of fake physics. is string theory based multiverse fake physics?
  22. Will K

    B Is the Universe Inside a Black Hole?

    "Before the big bang, scientists believe, the entire vastness of the observable universe, including all of its matter and radiation, was compressed into a hot, dense mass just a few millimeters across." Isn't this describing what the singularity of a black hole is? Black holes spin extremely...
  23. FallenApple

    Philosophy of a Mathematical Multiverse

    So according to Max Tegmark, the highest level of multiverse is mathematical. Obviously this is very controversial as this goes into the realm of metaphysics. I wonder what this community thinks about it. Personally, this makes sense. Everything in physics is described using math. For example...
  24. Greg Bernhardt

    B Sean Carroll on Why Does Time Exist at All?

    Interesting TedTalk from Sean Carroll last month. At the end he asks the question of whether the big bang was really the beginning. Is this simple multiverse talk? Thoughts?
  25. T

    I Cardinality of Universes in the Multiverse

    Is there a consensus on the cardinality of the infinite number of universes in the Multiverse? Is it countable or more than countable? Is it the same in different theories?
  26. S

    Other Writing a Paper on the Multiverse: Tips for Quality Language & Content

    I'm currently writing a paper on the Multiverse. I do have a theory of my own and have made the outline and started working on it. However, the language seems to unscientific, in the sense, its not very objective and crisp. How do i improve the quality of language and content of the paper. Any...
  27. Ranku

    I Instability of the Higgs particle

    In the multiverse paradigm, the Higgs particle is said to be unstable. What does the instability of the Higgs particle mean? Could it spontaneously disappear? What are the conditions for something like that to happen? And what would be the fate of the universe if that were to happen - keeping in...
  28. S

    I What are the Different Types of Multiverse Theories in Cosmology?

    My understanding is that there are two types of multiverse discussed in cosmology: one where universes can form or break off from existing universes such that our universe sprouted from another. Each new universe could have different initial conditions and with an almost infinite number of...
  29. A

    B Infinite multiverse would contain the ridiculous?

    Sorry if this is in the wrong place. Happy for it to be moved. I've heard it said that a multiverse containing an infinite number of universes, would lead to the ridiculous. The argument is something like this: 1) An infinite number of universes contain an infinite amount of matter. 2)...
  30. zdroide

    B H boson is 125 GeV, super symmetry, multiverse not possible?

    What other theories this number make impossible or improbable. When final number was given I hear some older physicist saying for one " 40 years of works gone" second grinding "only 30 for me!" We are ask to follow establish science. Seem to me that lots of theories was built on other's ones and...
  31. W

    I What Are the Proposed Alternatives to the Multiverse Theory?

    It has been argued that constants of nature are fine tuned for life. Many in the physics community explain this by a selection effect in the multiverse. However some seem unhappy with this , so what alternatives do they suggest?
  32. trinko

    A Hawking multiverse implications for "all" histories

    After reading Hawking's Grand Design I'm curious about what appears to be an inconsistency in his reasoning. His basis for the multiverse is that every permutation of M-Theory corresponds to different physical laws and that every possible history is relevant for predicting the state of a...
  33. billyp245

    Multiverse theory and Dark Matter

    I've been looking over the idea of the multiverse recently. I am trying to grasp exactly why so many physicists believe in the idea when it seems more philosophical than scientific. Are there any good indicators pointing towards the theory from QM or GR? The gripe that I also see with it...
  34. D

    Alex Vilenkin's paper about black holes and the multiverse

    What do you think about the following blog post about a recent paper by Alex Vilenkin about the possibility of black holes containing inflating universes? http://fqxi.org/community/forum/topic/2589
  35. A

    So.... The multiverse is unscientificly sound?

    According to science everything has a beginning and an end, even infenent genius. But the multiverse has no beginning and no end, it just keeps going. So in that line of thought, is science really fact, or just people trying to explained things like ancient cultures and their deities? btw, I'm...
  36. A

    A Is Multiverse proven by Plank data?

    Hi guys, On Wikipedia I found this article: http://www.ibtimes.co.uk/planck-univ...-holman-468831 The map showed anomalies that cosmologists believe could only have been caused by the gravitational pull of other universes outside our own. "These anomalies were caused by other universes...
  37. Q

    Exploring the Multiverse: Is a Non-Multiverse Possible?

    Hello, I am new here. I've had this in my head for a bit about the Multiverse theory, maybe some of you can give me some help at an answer ? Heregoes, In this supposedly "infinite" Multiverse idea, wouldn't there have to be a place for a universe where Multiverse simply did not exist ? Or...
  38. D

    Exploring the Multiverse: A Guide to Physics & Math for Self-Study

    I have a rudimentary background in physics and would like to do self-study for my own intellectual curiosity. If I wanted to try to get a grasp of something like M-Theory or inflationary cosmology, what physics subjects would I need to study first? Also what kinds of mathematics would I need...
  39. Hybrid

    I Many Worlds - Superdeterministic?

    Forgive me if this question has been asked previously on this board, but I cannot seem to find anything similar having searched around earlier. I suppose this blog entry written by the Physicist Robert Oerter linked below has accurately reflected how I feel about Many Worlds: "But now you see...
  40. A

    Does multiverse really explain fine-tuning?

    Hello everyone, I am not sure about this issue and this is the reason why I am asking this question. I can write many sentences on this topic, but I will try to make my point as short is possible. I will suppose you are familiar with multiverse idea and anthropic principle.. My question is...
  41. quantumfunction

    I Schrodinger's cat, the multiverse and isolated systems

    I know the debate about Schrodinger's cat is usually about things like consciousness but I want to talk about what it might say about isolated systems. Does the wave function of isolated systems remain in a superposition of observable states no matter how large the system gets? Say you have...
  42. N

    How Does Multiverse Theory Make *Every* Universe Possible?

    Is every combination possible based off of uncertainty? When the big bang happens in another universe and one electron moves slightly differently because of uncertainty it changes everything. Is that why there are "infinite" number of universes? When people say infinite do they really mean...
  43. M

    Properties of an evolved universe

    Hello All :) I've heard it proposed that a reason for the fine tuned nature of our universe in a way to allow the existence of complexity and life could be that the universe itself is the product of evolution in a multi-verse. I don't want to debate around the anthropological principle as I am...
  44. H

    Detecting the presence of other universes

    In the inflationary Big Bang model, our universe is one of the many pocket universes in the multiverse. How can we detect the existence of the other pocket universes? I presumed that all the pocket universes exist in the same physical space. So in principle, they can exert influence on one...
  45. Stephanus

    Farthest Object in Universe & Multiverse | Steven

    Dear PF Forum, After searching many links in Google and threads in PF, I can't find the farthest object in the universe. I have some questions here, perhaps someone can give me quick and simple answer. A. What is the farthest object in the universe? How far away? B. The radius of the...
  46. P

    Are there multiverse models with infinte regress?

    I seem to recall a documentary that I watched a few years ago describing the multiverse, with M-theory, as being similar to slices of bread, all next to each other. (Obviously just an analogy for the lay person). And when these two universes next to each other collided, it would create a new...
  47. slatts

    Is the Multiverse of Cantor Dust a Viable Solution to Olbers' Paradox?

    At my Wikipedia-minus-math level of understanding, the problem with any resolution of "Olbers' Paradox" through a fractal distribution (such as the "Cantor set" depicted in the Wikipedia article of that name) of stars or star clusters, rather than the alternative of a beginning of our multiverse...
  48. Vitaly Verlov

    Multiverse & Time Machine Physics

    Hi, My name is Vitaly, and I'm a visual effects artist and filmmaker. I'm planning to shoot a sci-fi short film, in the end of this April. The logline goes like this: A scientist must send a warning message through time before he gets killed by an assault team. It's going to be an intense...
  49. HZY

    Are present and future perspectives different?

    It is said that when an observer look up the sky and observe the cosmos, the further out he looks, the further back in time he sees, allowing him to peer into the past. However, there is a catch, namely, the observation must take place at present time. In other words, a distant object 100 light...
  50. C

    Are all universes the same age in the Multiverse?

    If we are part of a Multiverse is it likely that every universe is the same age ?
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