Olena Shmahalo / Quanta Magazine

Physicists are searching for evidence of an ancient collision with another universe.

Chapter 2: Colliding Universes

Multiverse Collisions May Dot the Sky

Early in cosmic history, our universe may have bumped into another — a primordial clash that could have left traces in the Big Bang’s afterglow.

Like many of her colleagues, Hiranya Peiris, a cosmologist at University College London, once largely dismissed the notion that our universe might be only one of many in a vast multiverse. It was scientifically intriguing, she thought, but also fundamentally untestable. She preferred to focus her research on more concrete questions, like how galaxies evolve.

Then one summer at the Aspen Center for Physics, Peiris found herself chatting with the Perimeter Institute’s Matt Johnson, who mentioned his interest in developing tools to study the idea. He suggested that they collaborate.

At first, Peiris was skeptical. “I think as an observer that any theory, however interesting and elegant, is seriously lacking if it doesn’t have testable consequences,” she said. But Johnson convinced her that there might be a way to test the concept. If the universe that we inhabit had long ago collided with another universe, the crash would have left an imprint on the cosmic microwave background (CMB), the faint afterglow from the Big Bang. And if physicists could detect such a signature, it would provide a window into the multiverse.

Erick Weinberg, a physicist at Columbia University, explains this multiverse by comparing it to a boiling cauldron, with the bubbles representing individual universes — isolated pockets of space-time. As the pot boils, the bubbles expand and sometimes collide. A similar process may have occurred in the first moments of the cosmos.

In the years since their initial meeting, Peiris and Johnson have studied how a collision with another universe in the earliest moments of time would have sent something similar to a shock wave across our universe. They think they may be able to find evidence of such a collision in data from the Planck space telescope, which maps the CMB.

Andrew Testa for Quanta Magazine

Video: University College London physicist Hiranya Peiris explains how the multiverse can be tested.

The project might not work, Peiris concedes. It requires not only that we live in a multiverse but also that our universe collided with another in our primal cosmic history. But if physicists succeed, they will have the first improbable evidence of a cosmos beyond our own.

When Bubbles Collide

Multiverse theories were once relegated to science fiction or crackpot territory. “It sounds like you’ve gone to crazy land,” said Johnson, who holds joint appointments at the Perimeter Institute of Theoretical Physics and York University. But scientists have come up with many versions of what a multiverse might be, some less crazy than others.

The multiverse that Peiris and her colleagues are interested in is not the controversial “many worlds” hypothesis that was first proposed in the 1950s and holds that every quantum event spawns a separate universe. Nor is this concept of a multiverse related to the popular science-fiction trope of parallel worlds, new universes that pinch off from our space-time and become separate realms. Rather, this version arises as a consequence of inflation, a widely accepted theory of the universe’s first moments.

Inflation holds that our universe experienced a sudden burst of rapid expansion an instant after the Big Bang, blowing up from a infinitesimally small speck to one spanning a quarter of a billion light-years in mere fractions of a second.

Yet inflation, once started, tends to never completely stop. According to the theory, once the universe starts expanding, it will end in some places, creating regions like the universe we see all around us today. But elsewhere inflation will simply keep on going eternally into the future.

This feature has led cosmologists to contemplate a scenario called eternal inflation. In this picture, individual regions of space stop inflating and become “bubble universes” like the one in which we live. But on larger scales, exponential expansion continues forever, and new bubble universes are continually being created. Each bubble is deemed a universe in its own right, despite being part of the same space-time, because an observer could not travel from one bubble to the next without moving faster than the speed of light. And each bubble may have its own distinct laws of physics. “If you buy eternal inflation, it predicts a multiverse,” Peiris said.

In 2012, Peiris and Johnson teamed up with Anthony Aguirre and Max Wainwright — both physicists at the University of California, Santa Cruz — to build a simulated multiverse with only two bubbles. They studied what happened after the bubbles collided to determine what an observer would see. The team concluded that a collision of two bubble universes would appear to us as a disk on the CMB with a distinctive temperature profile.

Olena Shmahalo/Quanta Magazine; source: S. M. Freeney et. al., Physical Review Letters

An ancient collision with a bubble universe would have altered the temperature of the cosmic microwave background (left), creating a faint disk in the sky (right) that could potentially be observed.

To guard against human error — we tend to see the patterns we want to see — they devised a set of algorithms to automatically search for these disks in data from the Wilkinson Microwave Anisotropy Probe (WMAP), a space-based observatory. The program identified four potential regions with temperature fluctuations consistent with what could be a signature of a bubble collision. When data from the Planck satellite becomes available later this year, researchers should be able to improve on that earlier analysis.

Yet detecting convincing signatures of the multiverse is tricky. Simply knowing what an encounter might look like requires a thorough understanding of the dynamics of bubble collisions — something quite difficult to model on a computer, given the complexity of such interactions.

When tackling a new problem, physicists typically find a good model that they already understand and adapt it by making minor tweaks they call “perturbations.” For instance, to model the trajectory of a satellite in space, a physicist might use the classical laws of motion outlined by Isaac Newton in the 17th century and then make small refinements by calculating the effects of other factors that might influence its motion, such as pressure from the solar wind. For simple systems, there should be only small discrepancies from the unperturbed model. Try to calculate the airflow patterns of a complex system like a tornado, however, and those approximations break down. Perturbations introduce sudden, very large changes to the original system instead of smaller, predictable refinements.

Modeling bubble collisions during the inflationary period of the early universe is akin to modeling a tornado. By its very nature, inflation stretches out space-time at an exponential rate — precisely the kind of large jumps in values that make calculating the dynamics so challenging.

“Imagine you start with a grid, but within an instant, the grid has expanded to a massive size,” Peiris said. With her collaborators, she has used techniques like adaptive mesh refinement — an iterative process of winnowing out the most relevant details in such a grid at increasingly finer scales — in her simulations of inflation to deal with the complexity. Eugene Lim, a physicist at King’s College London, has found that an unusual type of traveling wave might help simplify matters even further.

Waves of Translation

In August 1834, a Scottish engineer named John Scott Russell was conducting experiments along Union Canal with an eye toward improving the efficiency of the canal boats. One boat being drawn by a team of horses stopped suddenly, and Russell noted a solitary wave in the water that kept rolling forward at a constant speed without losing its shape. The behavior was unlike typical waves, which tend to flatten out or rise to a peak and topple quickly. Intrigued, Russell tracked the wave on horseback for a couple of miles before it finally dissipated in the channel waters. This was the first recorded observation of a soliton.

Russell was so intrigued by the indomitable wave that he built a 30-foot wave tank in his garden to further study the phenomenon, noting key characteristics of what he called “the wave of translation.” Such a wave could maintain size, shape and speed over longer distances than usual. The speed depended on the wave’s size, and the width depended on the depth of the water. And if a large solitary wave overtook a smaller one, the larger, faster wave would just pass right through.

Russell’s observations were largely dismissed by his peers because his findings seemed to contradict what was known about water wave physics at the time. It wasn’t until the mid-1960s that such waves were dubbed solitons and physicists realized their usefulness in modeling problems in diverse areas such as fiber optics, biological proteins and DNA. Solitons also turn up in certain configurations of quantum field theory. Poke a quantum field and you will create an oscillation that usually dissipates outward, but configure things in just the right way and that oscillation will maintain its shape — just like Russell’s wave of translation.

Because solitons are so stable, Lim believes they could work as a simplified toy model for the dynamics of bubble collisions in the multiverse, providing physicists with better predictions of what kinds of signatures might show up in the CMB. If his hunch is right, the expanding walls of our bubble universe are much like solitons.

However, while it is a relatively straightforward matter to model a solitary standing wave, the dynamics become vastly more complicated and difficult to calculate when solitons collide and interact, forcing physicists to rely on computer simulations instead. In the past, researchers have used a particular class of soliton with an exact mathematical solution and tweaked that model to suit their purposes. But this approach only works if the target system under study is already quite similar to the toy model; otherwise the changes are too large to calculate.

To get around that hurdle, Lim devised a neat trick based on a quirky feature of soliton collisions. When imagining two objects colliding, we naturally assume that the faster they are moving, the greater the impact and the more complicated the dynamics. Two cars ramming each other at high speeds, for instance, will produce scattered debris, heat, noise and other effects. The same is true for colliding solitons — at least initially. Collide two solitons very slowly, and there will be very little interaction, according to Lim. As the speed increases, the solitons interact more strongly.

Courtesy of the Perimeter Institute

A computer model of a collision between two bubble universes. The collision would alter the patterns in the cosmic microwave background.

But Lim found that as the speed continues to increase, the pattern eventually reverses: The soliton interaction begins to decrease. By the time they are traveling at the speed of light, there is no interaction at all. “They just fly right past each other,” Lim said. “The faster you collide two solitons, the simpler they become.” The lack of interactions makes it easier to model the dynamics of colliding solitons, as well as colliding bubble universes with solitons as their “edges,” since the systems are roughly similar.

According to Johnson, Lim has uncovered a very simple rule that can be applied broadly: Multiverse interactions are weak during high-speed collisions, making it easier to simulate the dynamics of those encounters. One can simply create a new model of the multiverse, use solitons as a tool to map the new model’s expected signatures onto cosmic microwave data, and rule out any theories that don’t match what researchers see. This process would help physicists identify the most viable models for the multiverse, which — while still speculative — would be consistent both with the latest observational data and with inflationary theory.

The Multiverse’s Case for String Theory

One reason that more physicists are taking the idea of the multiverse seriously is that certain such models could help resolve a significant challenge in string theory. One of the goals of string theory has been to unify quantum mechanics and general relativity, two separate “rule books” in physics that govern very different size scales, into a single, simple solution.

But around 10 years ago, “the dream of string theory kind of exploded,” Johnson said — and not in a good way. Researchers began to realize that string theory doesn’t provide a unique solution. Instead, it “gives you the theory of a vast number of worlds,” Weinberg said. A common estimate — one that Weinberg thinks is conservative — is 10500 possibilities. This panoply of worlds implies that string theory can predict every possible outcome.

The multiverse would provide a possible means of incorporating all the different worlds predicted by string theory. Each version could be realized in its own bubble universe. “Everything depends on which part of the universe you live in,” Lim said.

Peiris acknowledges that this argument has its critics. “It can predict anything, and therefore it’s not valid,” Peiris said of the reasoning typically used to dismiss the notion of a multiverse as a tautology, rather than a true scientific theory. “But I think that’s the wrong way to think about it.” The theory of evolution, Peiris argues, also resembles a tautology in certain respects — “an organism exists because it survived” — yet it holds tremendous explanatory power. It is a simple model that requires little initial input to produce the vast diversity of species we see today.

A multiverse model tied to eternal inflation could have the same kind of explanatory power. In this case, the bubble universes function much like speciation. Those universes that happen to have the right laws of physics will eventually “succeed” — that is, they will become home to conscious observers like ourselves. If our universe is one of many in a much larger multiverse, our existence seems less unlikely.

Uncertain Signals

Ultimately, however, Peiris’ initial objection still stands: Without some means of gathering experimental evidence, the multiverse hypothesis will be untestable by definition. As such, it will lurk on the fringes of respectable physics — hence the strong interest in detecting bubble collision signatures in the CMB.

Of course, “just because these bubble collisions can leave a signature doesn’t mean they do leave a signature,” Peiris emphasized. “We need nature to be kind to us.” An observable signal could be a rare find, given how quickly space expanded during inflation. The collisions may not have been rare, but subsequent inflation “tends to dilute away the effects of the collision just like it dilutes away all other prior ‘structure’ in the early universe, leaving you with a small chance of seeing a signal in the CMB sky,” Peiris said.

“My own feeling is you need to adjust the numbers rather finely to get it to work,” Weinberg said. The rate of formation of the bubble universes is key. If they had formed slowly, collisions would not have been possible because space would have expanded and driven the bubbles apart long before any collision could take place. Alternatively, if the bubbles had formed too quickly, they would have merged before space could expand sufficiently to form disconnected pockets. Somewhere in between is the Goldilocks rate, the “just right” rate at which the bubbles would have had to form for a collision to be possible.

Researchers also worry about finding a false positive. Even if such a collision did happen and evidence was imprinted on the CMB, spotting the telltale pattern would not necessarily constitute evidence of a multiverse. “You can get an effect and say it will be consistent with the calculated predictions for these [bubble] collisions,” Weinberg said. “But it might well be consistent with lots of other things.” For instance, a distorted CMB might be evidence of theoretical entities called cosmic strings. These are like the cracks that form in the ice when a lake freezes over, except here the ice is the fabric of space-time. Magnetic monopoles are another hypothetical defect that could affect the CMB, as could knots or twists in space-time called textures.

Weinberg isn’t sure it would even be possible to tell the difference between these different possibilities, especially because many models of eternal inflation exist. Without knowing the precise details of the theory, trying to make a positive identification of the multiverse would be like trying to distinguish between the composition of two meteorites that hit the roof of a house solely by the sound of the impacts, without knowing how the house is constructed and with what materials.

Should a signature for a bubble collision be confirmed, Peiris doesn’t see a way to study another bubble universe any further because by now it would be entirely out of causal contact with ours. But it would be a stunning validation that the notion of a multiverse deserves a seat at the testable physics table.

And should that signal turn out to be evidence for cosmic strings or magnetic monopoles instead, it would still constitute exciting new physics at the frontier of cosmology. In that respect, “the cosmic microwave background radiation is the underpinning of modern cosmology,” Peiris said. “It’s the gift that keeps on giving.”

This article was reprinted on Wired.com.

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  • Hi!

    I would like to add that the soliton work that Jennifer was referring to in the article was done in collaboration with Drs. Mustafa Amin and I-Sheng Yang, who actually did all the hard work!

    Eugene Lim

  • It’s not clear to me what a collision of multiverses mean. Collision means separation between two objects reducing below a threshold. However, space is defined only within the pocket universes and not in between. Only alternative I can think of is a collision in phase space, but if something like Louisville’s theorem holds (i.e. positing for no good reason some physics for the intermediate region) then there won’t be any collision in phase space. Also not clear why collision in phase space would leave a physical signature.

  • What predictions come from the multiverse other than possible patterns in the cosmic microwave background radiation? As the article mentioned these patterns could also come from other phyics

  • Let’s say her theory “proves” there is a multiverse.

    If there is a multiverse then there are an infinite number of universes (or close enough).

    With that many universes existing there will eb universe where the shapes she is seeking just happen coincidentally.

    If there are many universes where those shapes happen NOT due to collision then we can’t ever genuinely know if our universe’s shapes are because of universe-universe interaction or just by coincidence.

    Therefore, if the multiverse theory is correct then the multiverse theory is untestable. If the multiverse did exist it would instantly cast into doubt the very results that, in this case, prove it exists.

    Therefore, the multiverse theory is, in this case, untestable.

  • Jennifer — nice job on the article!

    In reply to a couple of comments posted:

    Dyutiman: there is spacetime between the bubbles. It is inflating, and filled with vacuum energy. You can think of the bubbles as expanding into a pre-existing medium, converting that medium to a lower-energy phase.

    Dave: yes, there are other ‘chance’ fluctuations and perturbations that could in principle look like a bubble collision. But their statistics are understood, so you can ask for a given signal what are the odds that it is a result of chance, versus a bubble collision. This is a tricky statistical problem, but Hiranya, Matt and others have done a very nice job of solving it (and I can praise them objectively since I was not involved in that work!)

    Jerry: the collision is a perturbation to the ‘initial’ conditions to the big-bang universe inside the bubble. Thus any probe of those initial conditions, and in particular any probe of the initial density fluctuations, can test the idea. For example, the arrangement of galaxies (current) or 21 cm surveys (future) might do it also. Currently the CMB is the most constraining, however.

  • We’ve already found evidence of the “ring” in the background pattern. http://arxiv.org/abs/1207.2498 is from 2012. At that time it was thought this might be pre-universe black holes that exploded into this universe, this is another theory to explain them?

    So, if the faster the “waves” go the simpler they become…is there a speed where they loose coherence? Is this the real universal information speed limit, eventually the edge of the Universes have an edge of whatever the lowest possible “informational” energy unit? We currently see “the speed of light” as OUR universe’s information transmission unit (at least for the macro world) yet this indicates the multiverse system itself has it’s own speed limit.

    “twists in space-time called textures” is a new one for me. Cosmic strings I’ve read about, magnetic monopoles isn’t a new theory either. Yet the rings could be both cosmic strings AND multiverse soliton wave collisions…in fact the collisions could spawn the strings themselves.

    There are so many string theories, this paper doesn’t indicate which this might lean to. It seems each new generation of cosmic background mappers brings out new resolutions that fundamentally impact our understanding of the origins of this universe. Plank’s been collecting data since 2013, what’s the hold up? I often wonder why the data from our probes takes over a year to get into the hands of data scientists.

  • to Dave (Nov 10, 2014 11:14pm) not sure if I agree with your characterization of infinity. Consider for example the set of all even numbers. Just because the set is infinitely large doesn’t mean all numbers are present, meaning odd numbers are absent. So infinite doesn’t mean anything goes.

  • A stupid question: how would an antimatter region border ( like http://science.nasa.gov/science-news/science-at-nasa/2009/14aug_ams/ ) be distinguishable from this border?

  • Running models to find a signature is something of an art-form. Hope to see exciting comparison imagery of the model signature and that of realty.

  • Do each of the colliding universes deform equally? Leaving a duplicate imprint on the other universes microwave background? Assuming it has such a thing.

  • I wonder if the singularity caused by a black hole isn’t an instance of to universes banging into each other?

  • I like the window exercise. Look out a window and you see something that is made up of energy, with or without visible light … it could be pitch black outside. You may see the sky, water and ice. All phase transitions of the H20 molecule . How many dimensions do we see ? Three or four ? Look at an electron and how many dimensions are there? Twenty eight ? The spooky force may relate to 11 dimensions in the forward or future direction, and 17 dimensions in the reverse or past direction … considering the direction of the arrow of time. Thus the universe may consist of 28 dimensions, all made up of energy that cannot be created or destroyed , but just changed in form. Like the pot of boiling water, heating the water changes the liquid water to steam which when in the water forms bubbles that rise to the top of the liquid water and escape as steam in an open pot. The greater the heat applied to the pot the larger the bubbles become and the faster they rise. Some of the bubbles may bump against other bubbles and combine. Look at the vacuum of space as energy in place of the pot of boiling water. What changes the vacuum into heat that starts the bubble universe model ?
    Albert Einstein was successful in imaging pictures in his mind as he formulated relativity and other theories. He never imagined his electrons with 28 dimensions and thus he could not envision the cause of the spooky force .

  • some scientists have claimed that other bubble universes whilst being next to us will never get any data-info-energy across because their innate laws will be different to ours and thus break down or worse scatter at the edge of both. Either way nothing will ever be able to be monitored-measured- perceived even [at this time]. Still good to look and maybe some debris not of this universe might be found [might]

  • I wanna be a cosmologist, then I can just make up a bunch of stuff and search for evidence in an entire universe of evidence to support it – and if I can’t find any evidence there, I’ll just make up more ‘universes’. What a job!

  • First, I am by no means a physicist. Barely even touched physics in high school (mid 70s). So forgive me if I use wrong words. I have imagined multiverse as being in the same space, rather than close too or near each other. My analogy has been to imagine a large jar of water. Water representing the “available” space. Put a few drops of various food coloring dyes. Each color representing a single universe. Each molecule of coloring remaining separate from any molecule of a different color. Hence each color being in a different “phase” and we cannot see them from our own color (universe). But each color has influence over others nearby via gravity or whatever. The closer in phase, the more influence.

    So in our universe, I imagined that other universes are all around and intertwined with us, but as humans we are mostly unable to detect them. I imagined that “dark energy” was in fact gravitational influences from these other universes, if they are close enough in phase to have enough influence.

    Okay, so as a “civilian” maybe I’m giving somebody a chuckle. But I needed to share that.


  • “…I know a room full of musical tunes. Some rhyme, some ching. Most of them are clockwork. Let’s go into the other room and make them work”. From the song “Bike” by Syd Barrett.

  • A problem with this theory. They are assuming that when the bubbles met, it left a circular impression on our universe and then the other universe simply vanished. That would be the only way we would detect a ‘circle’ later on. Otherwise, given the speed of light, if we were ever to detect ‘anything’ it would spell our doom as the other universe would be at our door step with its own laws of physics…. Am I missing something?

  • In searching for evidence for any hypothetical collision with another universe in the CMB, I would be extremely worried about the mind’s tendency to see patterns where none exist (such as seeing faces in oncoming cars, or clouds that look like animals). Any ringlike patterns in the CMB, teased out of the noise in the data, are as likely to be products of our imagination as to be genuine collision scars.

  • I am not very well versed in physics so my naivete will be showing.
    Anyway. Does collision presume space-time between universes? Also, would this interaction have occurred when our universe was relatively smaller and can it be presumed as this universe grows does the chance for collision increase or is this kind of speculation literally nonsense on my part?
    A little knowledge can be a dangerous thing to contemplate by.

  • Ben, This is how I would imagine it, I believe there is general understanding of randomness between each bubble i.e. the rate at which they move and the rate at which they expand. Some of these bubbles will contain more stuff and others less. Much like an explosion early on there will be many interactions between bubbles that are stronger as these bubbles ‘move’ the interactions will vary. If the rate at which each these universes expand is greater than the relative “movement” then you would expect to get more interactions. If they expand really slowly but move very quickly away from each other then they are less likely to interact.
    Mind you I am not a physicist and I live in a 3 D world so nothing that I just said is based on fact

  • I understand sequence as follows:
    1) it all started from string theory which is believed be some part of physics world to be legit and relevant
    2) string theory some day collapsed to statement of 10^500 worlds possibilty
    3) worlds were named universes. Easiest way to percept spaceous universe is bubble
    4) so our Universe now is considered a bubble (btw, that means that it has CENTER! Which was always denied by all sorts of cosmologists)
    5) if there are multiple bubbles they certainly may collide (why not? Unless they are moving away from each other due to their Multiversal Dark Energy? We are used to explain unknown with something unknown, don’t we?:)
    6) we can assume that our own bubble could collide with another bubble. We have detailed 2D copy of our early entire bubble as CMB map and can obviously find traces of collision since information could not be destructed no matter how weak those traces are. Though I have a question: why only 2-bubbles collision? There can be any number from 1 to 10^500 collisions with our bubble, right?

    If my layman’s understanding of this road to multiverse bubbles collision theory is correct then I can only say that each of above statements can be false and erroneous.

    And the second point: why do our string science leaders believe, that they can describe 11-dimensional world as easy and simple as 3D bubbles? And how they are going to find correct traces of collision of 11D objects on a 2D map?

  • These physicists need to stop taking themselves so seriously. No one can prove a multi-verse, that every possible action occurred in some alternate reality.

  • John Mullan like you i not a physicist but your idea seem interesting, just one thing would not it be dark matter not dark energy? It would seem to me that dark energy would be the effect of gravity from universes not mix in with ours.

  • I want to congrat all the people that are working in this subject because it is an very important question to our lives or/and the future… My opinion is that we are not seeing the best ways to test this possibility now, this project has so many variables and depends so much of it that if there is a real Multiverse you could never found it anyway. We need better strategies, more accurate ways to find the solution and if we don´t have the right tools and anknowledgement to do it now, so the future will provide us but at the same time we need to make the maximum of research now and that´s the reason why I´m giving here my opinion too… I think that the solution for the Multiverse question is gravity … Gravity you study , find the multiverse you are. Yoda 🙂

  • Understand that space and time have different dimensions. Space has the dimensions of speed and acceleration and space has the dimensions of location/origin and direction. As such time can only accelerate or stay constant, deceleration is only acceleration in the opposite direction. Time can only stop and not go backwards. I like to jump ahead and I envision a universe with galaxies made up of mostly or wholly made of collapsed stars/black holes and galaxy clusters of the same. This could explain dark matter and dark energy, I don’t need a mystical concept of dark matter and dark energy that I know nothing about, dark energy is simply where the dark matter has sucked up all the gravity around it. How is dark matter/energy detected? by it’s gravitational signature. How are black holes detected, by it’s gravitational signature. Understand the concept of time, separate from space and understand the concept of space separate from time and it leads you to ……………..

  • As to abstract math, in my final year of math studies, the one question on the final exam was to show
    that there is more than one infinity. The proof was to do a one to one and onto map of the set of all fractions between zero and one to the set of all fractions between zero and two. To further that argument, I throw in the transcendental numbers, i.e. Pi, square root of 2, e(base of the natural log).
    One can only conclude there is more than one infinity and therefore more than one universe. The concept of bubble universes explains so much and the pieces fit, that I can only conclude that it must be true.

  • I’ve recently come across the term, “invariant time frame” to explain the constant speed of light. It makes sense. Different time frames within our universe explains the concept of time speeding up and slowing down relative to our time frame and why the speed of light is constant/invariant. In a bubble universe, a time frame of one bubble would not be relative to another time frame of another bubble, but may be relative to an invariant time frame of the bubble universe. That is, if one were to transcend to another bubble universe the times would not be relevant. The idea that both universes would exist at the same time is a nonquestion.

  • I’m not at all as scientifically educated as all of you might be but I would like to ask a question that seems to make some of the people in our world somewhat scared.

    What if we are alone? What if we are the only planet, galaxy, universe, or multiverse with living people/ organisms?

  • I’m doing research on multiple universes. But I just don’t understand how space time could extend and how that could lead to the theory of “eternal inflation”.

    If someone could please take time out of their busy schedule to please explain this theory to me a little more I would be very grateful.

  • John Mullan. Sir, I agree with your thought that, multiverse as being in the same space, rather than close to or near each other. Thanks !!!

  • Excellent work & i look forward to someone joining quantum physics w/string theory asap. I’m hoping the theory of the multiverse wins out in the end!

  • is it a in our mind only ? its all random data ,data , data , or Qbits of them , continuous data appearing as discreet ones , chance , probabilities , potentialities , promises and uncertainties all knit together in all their possible permutations as and combinations and our mental faculties picking up one pattern or multiple patterns and playing around with it. When we put random data in some order in our mind they become "information" for us created by our mind, propagated by our mind. Otherwise its al an energy sink, and energy random manifestations of phenomena and noumena , life and non-life, mind and matter a chimera of kaleidoscopic fleeting possibilities . What cosmos fundamentally is , is something like our mind with all its dimensions and dimensionless ness.

  • Could universe collisions result in plastic deformation of the space-time of one or both universes? If so, could this plastic deformation be what dark matter actually is? Not a form of matter but simply deformed space-time mistaken as of the presence of matter.

  • So is the concept one whereby these multiverse bubbles rest against each other eternally, bounce off each other, or pass right through each other as they expand? Looking for an 'imprint' of a collision on the CMB implies one of the first two, but the last one seems more likely to me (specially considering the soliton portion of the article), and if that is the case then I'm not sure we would see any localized variation in the CMB.

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