What is Multiverse: Definition and 197 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. J

    I Probability, observers and the multiverse

    Not sure if I'm putting this in the right place! I have a question about probability and conscious observers. Aside from other arguments for and against a multiverse, does the idea that a multiverse could contain a vast number of consicous observes make it more likely, given that we find...
  2. R

    I Multiverse theory -- Why don't strange things happen here sometimes?

    If I have a brittle piece of rock and hit it with a hammer, can a round ball split of in some universe, verses in our universe a piece with rugged ends always form? If so, why do we always, in our universe seem to get "expected" results? Why dont strange things happen here sometimes? Why is our...
  3. R

    I Multiverse theory, I dont like it...

    In think the popular science discussion about multiverse theory has problems. For example, they suggest that in another universe, coffe is green. Problem, coffe in our universe is brown for a reason, it reflects brown light. If it would reflect green light, it must contain other chemical...
  4. haushofer

    A Inference from fine-tuning to a multiverse

    Dear all, I'm reading up on Bayesian inference, and recently read some papers about the fine-tuning argument (FTA) again. I'm not that interested in the details of this fine-tuning, or details of the multiverse. My question concerns Bayesian inference. I'll make an analogy about habitable...
  5. R0dr1go

    B Multiverse and Fictional Ideas

    I'm a 16 year old who has wondered this question for a while. If the multiverse theory is correct, and I understand correctly, there would be infinite universes in which each universe would be different from another in some form. If this is the case, would that mean that places and worlds that...
  6. S

    Nima Arkani-Hamed's opinion on Many Worlds?

    I was wondering what was the opinion of the physicist Nima Arkani-Hamed towards the Many Worlds interpretation. Is he open to the possibility of it being true? Does he support it?
  7. S

    I Multiple (Non-Interacting) Universes?

    Before anything, I would like to clarify that I am aware that this is speculative physics more than established mainstream physics (and Smoot is not claiming that his ideas are true). However I think that it is interesting to discuss these models even if they are not yet proven to be right. I...
  8. apostolosdt

    A Multiverse and observational evidence?

    Cosmology and multiverse are beyond my limited knowledge, but I came across the following article that aroused my curiosity. Although I am extremely cautious with "exotic" theories, I'd like to read any comments on that part of the article that a model proposed by cosmologist Laura...
  9. M

    Meaning of time in the multiverse theory

    This statement got me thinking, would it be possible for 1 universe (out of the infinite collection of universes) to be stationary infinitely alternating between state A & B, or using the dice analogy throwing a 1 and a 2 over and over effectively making this universe appear looped in time...
  10. omega

    I Direct limit of multiverse models of ZFC

    Let ##(M_i)_{i\in I}## be a multiverse of models of ZFC. By that I mean: Each ##M_i## is a well-founded model of ZFC. ##(I,\leq_I)## is a partially ordered set, and whenever ##i\leq_I j##, there is an embedding ##\tau^j_i:M_i\rightarrow M_j## such that the image of ##M_i## is a transitive...
  11. S

    Does Nobel laureate Saul Perlmutter support the Multiverse hypothesis?

    In this video () physicist Brian Greene interviews Nobel laureate Saul Perlmutter about several topics in cosmology. At minute 1:12:22 Greene asks Perlmutter about whether he considers that the world is described by mathematics or the world *is* mathematics. Perlmutter seems to answer that he...
  12. S

    Michio Kaku and Max Tegmark....?

    Did Max Tegmark talk about his Mathematical Universe hypothesis at this event (https://www.zimbio.com/photos/Brian+Cox/Michio+Kaku/rAcvFyE88Ul/World+Science+Festival)? And if that's the case, what was the opinion of Michio Kaku?
  13. S

    A Branes with any number "n" of dimensions and laws of physics?

    I had a few questions about this paper by Nima Arkani-Hamed, Georgi Dvali and Savas Dimopoulos (https://arxiv.org/abs/hep-th/9907209) which is closely related to the concept of branes (https://en.wikipedia.org/wiki/Brane) 1. The authors of the paper mention that the branes in the model could...
  14. S

    Edward Witten and the Mathematical Multiverse?

    Physicist Max Tegmark proposed that every mathematically possible universe exists [1]. According to Tegmark himself, when he published such ideas, he received mostly positive feedback from Edward Witten and David Vogan [2]. Due to this, I was wondering whether Witten has made reference to...
  15. L

    I Multiverse: How Many Universes Could Exist?

    If there was a multiverse composed of many universes how many would there be? As many as could be possible or a number fewer than that? And if fewer, what limits the number of possible universes?
  16. DanielJ2021

    I Infinite space in a finite bubble, in a Tegmark Level 2 multiverse?

    So I am a layman in physics, I admit I am trying to grasp big ideas piecemeal via articles, wikipedia and YouTube. I don't pretend to be educated in this regard but I am curious and willing to learn! The idea of the multiverse intrigues me. Sidestepping for a second the fact that the idea has...
  17. S

    Nobel laureates who may consider the multiverse hypothesis?

    Apart from Frank Wilczek, Kip Thorne, and perhaps Gerard 't Hooft, are there any more (living) Nobel laureates in physics who are open to the possibility that multiple universes exist?
  18. J

    Is Multiverse the ultimate sci-fi?

    Multiverse is about other universes with all kinds of laws of nature. This means all science fiction ideas or scenerios can play out or exist to some extent, like Harry Potter. Hence anything fantasy or science fiction you can think of is overtaken by this Multiverse concept believed by...
  19. S

    I Wheeler's Pre-geometry model and multiple universes?

    John A Wheeler proposed that the universe emerged from a primordial chaos (some sort of pre-geometry or pre-space) from where all physics emerged in the universe. I thought this could be interesting in the context of multiple universes. Therefore, has any well renowned physicist considered...
  20. S

    Abour Riccardo Giacconi's opinion about the multiverse?

    Riccardo Giacconi (1931-2018) was an italian astrophysicist who was awarded with the Nobel prize in physics back in 2002 for his important contributions to astrophysics. Since he was an astrophysicist he must have heard about the multiverse hypothesis, but I have not found a single paper or...
  21. bland

    I Can the multiverse hypothesis be an explanation for life on Earth?

    Specifically he homes in on the multiverse and the 10^500 number that crops up. Basically he ends up saying that the whole concept of the multiverse virtually renders any TOE into pointless oblivion. So with this in mind I was wondering if I could also use the multiverse as an explanation for...
  22. C

    B If the Multiverse is correct why don't they appear inside our own?

    How did you find PF?: Google search If the initial conditions for our Universe was empty, timeless space and a quantum fluctuation created the entire Cosmos why have we not seen this repeated endlessly in the empty space within our own Universe?
  23. S

    A Can there be a lawless universe (according to Hawking)?

    I got a phrase from a book that Stephen Hawking and his daughter Lucy Hawking published in 2011. The book is "George and the Big Bang" which is a science fiction book prepared for children. I read a phrase on that book that interested me. It was: "Perhaps there are many universes, each with...
  24. S

    A Can Cosmic Inflation and String Theory change fundamental laws?

    Is there any version of string theory or cosmological inflation that allows the most fundamental laws and constants change between universes? String Theory and Cosmological Inflation are two theories or models that allow multiple universes to exist. Laws and constants of physics could change...
  25. S

    Does Michio Kaku agree with Lawrence Krauss' concept of nothingness?

    Michio Kaku and Lawrence Krauss are both well-renowned physicists who propose that the universe (or universes) was generated out of nothing. Krauss, in his book "A Universe from Nothing" argued that the universe was probably created by a primordial "nothingness" with no space and time and...
  26. S

    A Could different outcomes have different physics in Wigner's friend?

    Summary: Could different outcomes have different physics in Wigner's friend? Physicist Eugene Wigner said that consciousness was fundamental for physics and that laws of physics existed because of it. He said that "consciousness can change the usual laws of physics" He also proposed the...
  27. S

    I The Multiverse and 'No boundary' conditions approach in cosmology

    Summary: Questions about the Multiverse hypothesis and the 'No boundary' conditions approach in cosmology I have some questions about James Hartle and Stephen Hawking's 'No-boundary' proposal: - In their approach multiple histories would exist. These histories could yield universes with...
  28. S

    Did Paul Dirac believe in multiple universes?

    Prominent physicist Paul Dirac proposed a hypothesis that indicated that constants and laws of physics would evolve with time into different constants and laws of nature (https://en.wikipedia.org/wiki/Dirac_large_numbers_hypothesis) This hypothesis was used by Robert Dicke...
  29. S

    A Does Bohmian Mechanics yield the existence of a multiverse?

    David Deutsch, a theoretical physicist, talks about David Bohm in his book "the Fabric of Reality": "[w]orking out what Bohm’s invisible wave will do requires the same computations as working out what trillions of shadow photons will do. Some parts of the wave describe us, the observers...
  30. S

    Does Lawrence Krauss believe in the anthropic principle?

    Summary: Does Lawrence Krauss believe in the anthropic principle? I have read a lot of texts both indicating that physicist Lawrence Krauss is against the anthropic principle. But I have read several texts indicating that Lawrence Krauss believes that this principle is true and has developed...
  31. S

    I Did Wheeler consider Carter's anthropic multiverse?

    Physicist John Wheeler wrote an article called "Genesis and Observership" where he said near the end: "We have reviewed the evidence out of the big bang tat the universe did come into being and the evidence that not only space but all the structures and laws of physics are mutable. In the...
  32. S

    Could MWI create universes with fundamentally different physical laws?

    Summary: Could MWI (Many Worlds Interpretation) create universes with fundamentally different physical laws? Physicist John Wheeler proposed along with Hugh Everett and Bryce DeWitt the 'Many Worlds' Interpretation of Quantum Mechanics (although he expressed some doubts about its validity) I...
  33. S

    I Does the Strong Anthropic Principle have any equivalent specific model?

    The anthropic principle is a philosophical consideration that observations of the universe must be compatible with the conscious and sapient life that observes it. There are two main types of anthropic principle: Weak Anthropic Principle (WAP) and Strong Anthropic Principle (SAP) The Strong...
  34. Quantum Alchemy

    B A Question about space and the multiverse

    My question is about space and the multiverse. I was reading work by Max Tegmark and he sees the multiverse as Level 1-4. A Level 1 multiverse seems like it's self evident and I was wondering about the evidence against it. It's simple: Space expands faster than we can observe it so we exist in...
  35. S

    A Is Seth Lloyd's cosmological model background independent?

    I have been interested in Seth Lloyd's cosmological model (which proposes that the universe is a some kind of quantum computer or at least similar to it: https://en.wikipedia.org/wiki/Programming_the_Universe, https://arxiv.org/abs/quant-ph/0501135) since long ago. I was wondering if his...
  36. S

    I Is the Wheeler-DeWitt equation somehow related to the Multiverse?

    I've seen some articles that relate them (like this one: https://arxiv.org/pdf/1407.3118.pdf) "In this paper we will analyze the third quantization of gravity in path integral formalism. We will use the time-dependent version of WheelerDeWitt equation to analyze the multiverse in this...
  37. S

    I "It from Bit" and the multiverse?

    Did physicist John Archibald Wheeler propose the existence of multiple universes through his "It from Bit" or "Participatory Universe Principle" or "Law without Law and Pregeometry"? Is the multiverse related to Wheeler's ideas? I've been told that It can produce multiple universes, obviously...
  38. S

    I What multiverse model is this author referring to?

    John's Barrow book "The Constants of Nature" in chapter 13, he talks about a hypothetical multiverse composed of universes governed by other logics. Specifically, he talks about different approaches that physicists take when studying the multiverse, and he mentions a radical approach where even...
  39. multiversetheory

    B If there is no multiverse then what is beyond the Universe?

    I have been trying to think if there is no multiverse and the universe is not infinite than what is on the outside?
  40. J

    I Fine tuning and the multiverse

    Hi New to this forum. I am not a physics student but someone with an interest in aspects of physics, particularly cosmology. This is a question regarding fine tuning and the multiverse as a possible answer. The following is a link to a Youtube video in the Closer to Truth series, and the...
  41. jedishrfu

    Multiverse vs Ugliverse vs Quantum Monism

    In a recent Scientific American article the notions of multi-verse and ugli-verse are examined as dangerous ideas which can stop Physics from looking for deeper truths since they are based in the universe that supports intelligent life. The notion is to extend beyond Everett's Many Worlds...
  42. E

    I Understanding the Multiverse per David Deutsch

    I find David Deutsch to be interesting, however I find his writing style a little hard to follow at times. If anyone can shed light on what he means by the following, it would be appreciated: "the multiverse is not a discrete set of universes but a continuum" I can accept the concept of a...
  43. Tree Universe

    A Model of the Universe/Multiverse

    Hi Everyone, One of Hawking's last publications studied the model of universe/multiverse and conjectured that the exit from eternal inflation is "finite and reasonably smooth" - in other words, the inflated boundaries of multiverses could be finite and smooth. Here is the paper link -...
  44. T

    B Multiverse with and without me

    Hi All I'm a new comer to this forum, excuse my posting a question in a reply section but I can't find where to post a question. I just want to put forward a thought I had in relation to the existence of the multiverse idea, here in lies my query: if all my possible outcomes in my life are...
  45. S

    A Could information in a boundary be modified once encoded?

    Could information in a boundary be modified once encoded in holographic principle?There are models of universes where holographic principle has a different correspondence (there is absolutely no reason to assume that this would hold true for all possible universes. You could have a universe...
  46. Mlesnita Daniel

    B Why the multiverse makes no sense to me

    So, basically, multiverse make sense because we can't imagine our universe standing in nothing(or being everything that just expands itself). If we take this principle, we should have a multi-multiverse, a multi-multi-multiverse and so on. (When the chain ends?). Is it more evidence to support...
  47. Kaustubh Namjoshi

    I Gravitational waves and the multiverse

    Assuming that the multiverse hypothesis is true and a singularity at the center of a black hole can give rise to another baby universe. Can we detect such an event in the LIGO observatory?
  48. C

    Parallel Universes: Multiverse vs Many Worlds - Splits?

    Hi, sorry - forgive me for posting (I am not much of a science guy but I am still interested). I am just watching a documentary (I know not a great source for scientific information - but it got me thinking). In the documentary it talks about the many worlds theory (which I believe is different...
  49. tatkhj

    How do the Mobius and Klein models illuminate string theory?

    I'm a speculative fiction writer and playwright, a retired archirect with a master of architecture degree in theory, and a theater producer, director, and acting improvisor. I'm currently working on a TV series of 169 episodes exploring life in a contemporary parallel universe very much like...
  50. 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= At some part, he says: 3.2 Non-uniqueness: Possibilities There is non-uniqueness at both steps. Stating “all that is possible...