In the bizarre quantum world we have electrons that literally disappear, re-appear some place else. Electrons that can be in multiple places at the same time. Professor Micho Kaku, author Physics of the Impossible
There was a time when universe meant all there is. Everything. Brian Greene, Beyond The Cosmos: Multiverse, National Geographic 2012
There’s more. A lot more. That our universe is not alone. There may be other universes, in fact there might be new ones being born all the time. We may actually live in an expanding sea of multiplying universes – a multiverse. ibid.
If there are an infinite number of universes in the multiverse, somewhere there’s a place that’s almost identical to ours, except for the slightest details. ibid.
We really may be part of a multiverse ... The generally accepted theory of the origin of our universe – the Big Bang. ibid.
Guth: Gravity can act in reverse. ibid.
Guth called this short burst of expansion inflation ... the powerful repulsive gravity of inflation was the bang in the Big Bang. ibid.
Quantum Physics: The tiniest scale ... These sub-atomic bits might actually be made of something smaller – tiny vibrating strands. ibid.
Strings can take on different properties. ibid.
Extra dimensions of space ... The shape of those extra dimensions determines the fundamental features of our universe. ibid.
Extra dimensions can be curled up. ibid.
String theory was describing a multiverse. ibid.
Eternal Inflation + Dark Energy + String Theory = We may live in a multiverse. ibid.
There’s every reason to expect that in the different big bangs that occur you will have different conditions, different values, for what we call the Fundamental Constants. So the fact that the Constants of Nature are suitable for life which is clearly true, we observe may not be a universal fact, may be an accident. Professor Steven Weinberg, interview Professor Richard Dawkins
If the multiverse is indeed infinite then one is going to have to confront a lot of possibilities that are hard to imagine. Professor Steven Weinberg
We have to make our bets. And I think right now the multiverse is a pretty good bet. Professor Steven Weinberg
I’m very uncomfortable with the multiverse. Andreas Albrecht, University of California
It exists in the same way that angels might exists. David Gross
For a start, how is the existence of the other universes to be tested? To be sure, all cosmologists accept that there are some regions of the universe that lie beyond the reach of our telescopes, but somewhere on the slippery slope between that and the idea that there are an infinite number of universes, credibility reaches a limit. As one slips down that slope, more and more must be accepted on faith, and less and less is open to scientific verification. Extreme multiverse explanations are therefore reminiscent of theological discussions. Indeed, invoking an infinity of unseen universes to explain the unusual features of the one we do see is just as ad hoc as invoking an unseen Creator. The multiverse theory may be dressed up in scientific language, but in essence it requires the same leap of faith. Paul Davies, A Brief History of the Multiverse
As skeptical as I am, I think the contemplation of the multiverse is an excellent opportunity to reflect on the nature of science and on the ultimate nature of existence: why we are here ... In looking at this concept, we need an open mind, though not too open. It is a delicate path to tread. Parallel universes may or may not exist; the case is unproved. We are going to have to live with that uncertainty. Nothing is wrong with scientifically based philosophical speculation, which is what multiverse proposals are. But we should name it for what it is. George Ellis, Scientific American, Does the Multiverse Really Exist?
A common feature of all four multiverse levels is that the simplest and arguably most elegant theory involves parallel universes by default. To deny the existence of those universes, one needs to complicate the theory by adding experimentally unsupported processes and ad hoc postulates: finite space, wave function collapse and ontological asymmetry. Our judgment therefore comes down to which we find more wasteful and inelegant: many worlds or many words. Perhaps we will gradually get used to the weird ways of our cosmos and find its strangeness to be part of its charm. Max Tegmark, article Scientific American 2003
A pervasive idea in fundamental physics and cosmology that should be retired: the notion that we live in a multiverse in which the laws of physics and the properties of the cosmos vary randomly from one patch of space to another. According to this view, the laws and properties within our observable universe cannot be explained or predicted because they are set by chance. Different regions of space too distant to ever be observed have different laws and properties, according to this picture. Over the entire multiverse, there are infinitely many distinct patches. Among these patches, in the words of Alan Guth, ‘Anything that can happen will happen – and it will happen infinitely many times.’ Hence, I refer to this concept as a Theory of Anything. Any observation or combination of observations is consistent with a Theory of Anything. No observation or combination of observations can disprove it. Proponents seem to revel in the fact that the Theory cannot be falsified. The rest of the scientific community should be up in arms since an unfalsifiable idea lies beyond the bounds of normal science. Yet, except for a few voices, there has been surprising complacency and, in some cases, grudging acceptance of a Theory of Anything as a logical possibility. The scientific journals are full of papers treating the Theory of Anything seriously. What is going on? Paul Steinhardt, Theories of Anything edge online
It’s the strangest idea in the whole of science. It emerged by accident from bizarre experiments. Scientists resisted it. But a maverick would force them to take it seriously. The idea means we live in a giant bubble. Parallel Universes, National Geographic 2011
Some of the world’s most respected scientists claim these other worlds may actually exist. ibid.
Some exist far beyond the further edge of our visible universe, others hang out in a mysterious landscape full of dark energy called the Multiverse, and others are right here in the same space we are all living, but we can’t see them obviously. ibid.
You might not want to meet your other self. ibid.
[Hugh] Everett wrote what’s become the definitive argument for parallel universes called Many Worlds. ibid.
An infinite number of other realities. ibid.
There may be other worlds out there. Where there could be an exact copy of our solar system, our Earth and each one of us. The Universe s3e2: Parallel Universes
The universe sits in a sea of parallel universes. ibid.
Remarkably, there may be four types of parallel universe out there: one could exist in exactly the same space that we are in, but it is so far away we cannot see it or reach it. In another scenario, multiple giant universes could exist in giant cosmic soap bubbles adrift in a cosmic sea of giant bubbles. In yet another scenario, many parallel universes occupy the same space and times as our universe, but because they are in different dimensions, they are invisible. In yet another, all the laws of physics are different so everything looks completely different. ibid.
The Wmap seems to show that the universe is flat. ibid.
‘We are children of the bubble.’ ibid. Tegmark
When In the 1980s scientists came up with a lyrical-sounding idea – String Theory – it promised to solve all the mysteries of the universe, including whether or not parallel universes are real. The idea is that all particles are not solid points or dots, as science said they were. Instead, if you could see up close, particles are in fact tiny string-like objects that individually vibrate in various ways ... String Theory has now evolved into M or M-brane theory. ibid.
The crowning achievement of M Theory came when scientists realised that to make sense of everything, you need to think of the universe as existing in eleven dimensions. M Theory explains how the tiniest as well as the biggest things in the cosmos work. It also proposes that we all live on a giant and energetic M-brane. Our universe is tethered to this wall by extra dimensions ... These M-branes are also very close to each other. ibid.
‘We are probably nearing the limit of all we can know about astronomy.’ The Entire History of the Universe e13: How Many Multiverses Are There? Simon Newcombe
These are new universes born beyond our cosmic horizon in our distant cosmic past. ibid.
Multiverse theories have proliferated hoping to answer the deepest questions. ibid.
Just what is beyond the observable universe? ibid.