Multiverse Definition and 62 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. 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...
  2. 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?
  3. 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...
  4. 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...
  5. 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...
  6. S

    Michio Kaku and Max Tegmark....?

    Did Max Tegmark talk about his Mathematical Universe hypothesis at this event ( And if that's the case, what was the opinion of Michio Kaku?
  7. 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 ( which is closely related to the concept of branes ( 1. The authors of the paper mention that the branes in the model could...
  8. 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?
  9. 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...
  10. 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...
  11. 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...
  12. 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...
  13. 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...
  14. 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...
  15. 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 ( This hypothesis was used by Robert Dicke...
  16. 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...
  17. 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...
  18. 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...
  19. 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...
  20. 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...
  21. 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...
  22. 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:, since long ago. I was wondering if his...
  23. S

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

    I've seen some articles that relate them (like this one: "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...
  24. 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...
  25. 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...
  26. 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 -...
  27. 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...
  28. 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...
  29. 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...
  30. S

    A Multiverse theory with impossible universes?

    I found an article written by physicist George Ellis that confused me a little. At some part, he says: 3.2 Non-uniqueness: Possibilities There is non-uniqueness at both steps. Stating “all that is possible...
  31. 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...
  32. 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"...
  33. nomadreid

    I Bubble universe connections?

    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...
  34. 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...
  35. 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...
  36. 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?
  37. 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...
  38. 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...
  39. 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...
  40. 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...
  41. 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...
  42. 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?)
  43. 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...
  44. 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...
  45. 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?
  46. 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...
  47. 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...
  48. 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...
  49. 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...
  50. 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...