Searching for the Multiverse

What lies beyond the edges of the observable universe? Is it possible that our universe is just one of many in a much larger multiverse?

Movies can’t get enough of exploring these questions. From Oscar winners like Everything Everywhere All at Once to superhero blockbusters like Dr. Strange in the Multiverse of Madness, science fiction stories are full of creative interactions between alternate realities. And depending on which cosmologist you ask, the concept of a multiverse is more than pure fantasy or a handy storytelling device.

Humanity’s ideas about alternate realities are ancient and varied—in 1848 Edgar Allan Poe even wrote a prose poem in which he fancied the existence of “a limitless succession of Universes.” But the multiverse concept really took off when modern scientific theories attempting to explain the properties of our universe predicted the existence of other universes where events take place outside our reality.

“Our understanding of reality is not complete, by far,” says Stanford University physicist Andrei Linde. “Reality exists independently of us.”

If they exist, those universes are separated from ours, unreachable and undetectable by any direct measurement (at least so far). And that makes some experts question whether the search for a multiverse can ever be truly scientific.

Will scientists ever know whether our universe is the only one? We break down the different theories about a possible multiverse—including other universes with their own laws of physics—and whether many versions of you could exist out there.

What is a multiverse?
The multiverse is a term that scientists use to describe the idea that beyond the observable universe, other universes may exist as well. Multiverses are predicted by several scientific theories that describe different possible scenarios—from regions of space in different planes than our universe, to separate bubble universes that are constantly springing into existence.  READ MORE...

Is There Really a Multiverse?

• 
  
  The notion of parallel universes leapt out of the pages of fiction into scientific journals in the 1990s. Many scientists claim that mega-millions of other universes, each with its own laws of physics, lie out there, beyond our visual horizon. They are collectively known as the multiverse.
• The trouble is that no possible astronomical observations can ever see those other universes. The arguments are indirect at best. And even if the multiverse exists, it leaves the deep mysteries of nature unexplained.

In the past decade an extraordinary claim has captivated cosmologists: that the expanding universe we see around us is not the only one; that billions of other universes are out there, too. There is not one universe—there is a multiverse. 

In Scientific American articles and books such as Brian Greene’s latest, The Hidden Reality, leading scientists have spoken of a super-Copernican revolution. In this view, not only is our planet one among many, but even our entire universe is insignificant on the cosmic scale of things. It is just one of countless universes, each doing its own thing.

The word “multiverse” has different meanings. Astronomers are able to see out to a distance of about 42 billion light-years, our cosmic visual horizon. We have no reason to suspect the universe stops there. Beyond it could be many—even infinitely many—domains much like the one we see. 

Each has a different initial distribution of matter, but the same laws of physics operate in all. Nearly all cosmologists today (including me) accept this type of multiverse, which Max Tegmark calls “level 1.” Yet some go further. They suggest completely different kinds of universes, with different physics, different histories, maybe different numbers of spatial dimensions. 

Most will be sterile, although some will be teeming with life. A chief proponent of this “level 2” multiverse is Alexander Vilenkin, who paints a dramatic picture of an infinite set of universes with an infinite number of galaxies, an infinite number of planets and an infinite number of people with your name who are reading this article.

Similar claims have been made since antiquity by many cultures. What is new is the assertion that the multiverse is a scientific theory, with all that implies about being mathematically rigorous and experimentally testable. I am skeptical about this claim. 

I do not believe the existence of those other universes has been proved—or ever could be. Proponents of the multiverse, as well as greatly enlarging our conception of physical reality, are implicitly redefining what is meant by “science.”  READ MORE...

Multiverse Theory

Interest in the multiverse theory, suggesting that our universe is just one of many, spiked following the release of the movie Everything Everywhere All At Once. The film follows Evelyn Wang on her journey to connect with versions of herself in parallel universes to ultimately stop the destruction of the multiverse.

The multiverse idea has long been an inspiration for science fiction writers. But does it have any basis in science? And if so, is it a concept we could ever test experimentally?

That’s the topic of the third episode of our podcast Great Mysteries of Physics – hosted by me, Miriam Frankel, science editor at The Conversation, and supported by FQxI, the Foundational Questions Institute.

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“One way to think of a multiverse is just to say: ‘Well, the universe might be really, really big – much bigger than our observable universe – and so there could be other regions of the universe that are far beyond our horizon that have different things happening in them’,” explains Katie Mack, Hawking chair in cosmology and science communication at the Perimeter Institute for Theoretical Physics in Canada. “And I think that idea is totally well accepted in cosmology.”  READ MORE...

Multiverse Theory

Multiverse theory suggests that our universe, with all its hundreds of billions of galaxies and almost countless stars, spanning tens of billions of light-years, may not be the only one. Instead, there may be an entirely different universe, distantly separated from ours — and another, and another. 

Indeed, there may be an infinity of universes, all with their own laws of physics, their own collections of stars and galaxies (if stars and galaxies can exist in those universes), and maybe even their own intelligent civilizations.

It could be that our universe is just one member of a much grander, much larger multitude of universes: a multiverse.  The concept of the multiverse arises in a few areas of physics (and philosophy), but the most prominent example comes from something called inflation theory. 

Inflation theory describes a hypothetical event that occurred when our universe was very young — less than a second old. In an incredibly brief amount of time, the universe underwent a period of rapid expansion, "inflating" to become many orders of magnitude larger than its previous size, according to NASA.

Inflation of our universe is thought to have ended about 14 billion years ago, said Heling Deng, a cosmologist at Arizona State University and an expert in multiverse theory. "However, inflation does not end everywhere at the same time," Deng told Live Science in an email. "It is possible that as inflation ends in some region, it continues in others."

Thus, while inflation ended in our universe, there may have been other, much more distant regions where inflation continued — and continues even today. Individual universes can "pinch off" of larger inflating, expanding universes, creating an infinite sea of eternal inflation, filled with numerous individual universes.

In this eternal inflation scenario, each universe would emerge with its own laws of physics, its own collection of particles, its own arrangement of forces and its own values of fundamental constants. This might explain why our universe has the properties it does — particularly the properties that are hard to explain with fundamental physics, such as dark matter or the cosmological constant, Deng said.

"If there is a multiverse, then we would have random cosmological constants in different universes, and it is simply a coincidence that the one we have in our universe takes the value that we observed," he said.   READ MORE...

Everywhere... Everything is Explained...

This is Michelle Yeoh in the very fantastic Everything Everywhere All at Once. In it she plays a mom,

and her story made me want to call my mom.   Courtesy of A24

This past weekend, a couple of my friends and I went to see Everything Everywhere All at Once. I went in knowing two things about it: The first was that the very talented and fantastic Michelle Yeoh was in it; and the second was that it involved the “multiverse.”

As the credits rolled, with tears trickling into my mask, I had a hard time discerning what was making me emotional. I say emotional because it wasn’t just one feeling, but a strange mix of several: joy, wistfulness, catharsis, yearning, hope.

Without giving too much away, the very simple gist of this maximalist, fantastic tornado of a movie is about the choice to exist, to fully live within the present moment. It’s about finding the beauty in our small, odd lives, even as we constantly compare what we have to our unfulfilled fantasies. The movie also examines how we take solace in the personal disasters we’ve narrowly avoided. But what makes Everything Everywhere All at Once so powerful is the multiverse, a dazzling antidote to the fact that real life these days feels like it’s been designed to blur and pummel our emotions into dullness.

What is the multiverse? A world full of endless potential; multiple parallel universes spinning in synchronicity; and the possibility of alternate, powerful, seemingly better versions of ourselves. At a time when a pandemic, wars, and political cruelty have become constant, inevitable presences in our daily lives, it’s the ultimate fantasy for this moment. And that’s not just because Marvel, the most powerful entertainment company in the world, has gone all-in and made the multiverse a cornerstone of its current storytelling.  READ MORE...

Multiple Universes

If the multiverse exists, there could be another you somewhere out there, doing exactly what you're doing now. (Image credit: Getty Images)

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".  SOURCE:  Wikipedia

Multiverse Theory 

...suggests that our universe, with all its hundreds of billions of galaxies and almost countless stars, spanning tens of billions of light-years, may not be the only one. Instead, there may be an entirely different universe, distantly separated from ours — and another, and another. Indeed, there may be an infinity of universes, all with their own laws of physics, their own collections of stars and galaxies (if stars and galaxies can exist in those universes), and maybe even their own intelligent civilizations.

It could be that our universe is just one member of a much grander, much larger multitude of universes: a multiverse.

The concept of the multiverse arises in a few areas of physics (and philosophy), but the most prominent example comes from something called inflation theory. Inflation theory describes a hypothetical event that occurred when our universe was very young — less than a second old. In an incredibly brief amount of time, the universe underwent a period of rapid expansion, "inflating" to become many orders of magnitude larger than its previous size, according to NASA.

Inflation of our universe is thought to have ended about 14 billion years ago, said Heling Deng, a cosmologist at Arizona State University and an expert in multiverse theory. "However, inflation does not end everywhere at the same time," Deng told Live Science in an email. "It is possible that as inflation ends in some region, it continues in others."

Thus, while inflation ended in our universe, there may have been other, much more distant regions where inflation continued — and continues even today. Individual universes can "pinch off" of larger inflating, expanding universes, creating an infinite sea of eternal inflation, filled with numerous individual universes.  READ MORE...

A Time Without Time

Eternal inflation is a hypothetical inflationary universe model, which is itself an outgrowth or extension of the Big Bang theory.  According to this theory, the inflationary phase of the universe's expansion lasts forever throughout most of the universe. Because the regions expand exponentially rapidly, most of the volume of the universe at any given time is inflating. Eternal inflation, therefore, produces a hypothetically infinite multiverse, in which only an insignificant fractal volume ends inflation.

The idea of the inflation of the Universe started in the 1970's when a belief developed that within nanoseconds of the BIG BANG, the universe expanded exponentially.

But Stephen Hawking does not agree with that theory and believes that external inflation does not occur.

Eternal inflation emerges because, in the very early universe, the quantum fluctuations in the field that drives inflation are as big as the field’s average value. But Hawking argues that under those conditions one cannot simply carry on with Albert Einstein’s general theory of relativity, but instead must use a maneuver like Maldacena’s to view the entire situation in a space with one less dimension. In that alternative space, things are more tractable, they claim, and the physics does not lead to eternal inflation. Instead, a single, well-behaved universe merges.

In 1997, Argentine-American theorist Juan Maldacena considered a volume of space in which gravity was at work. It’s like saying whatever goes on inside a can of soda can be captured by a theory describing only what’s happening on the can’s surface.

So in Hawking’s through the principle of holography, the very early universe should be described by a theory with just three spatial dimensions and no time.

And, while this author is no theoretical physicist, I wonder quite innocently I would have to say, where does time come from when it finally appears?  And if it does finally appears which we all can agree that it does, then what caused time to be created?  And, can time's creation be attributed to the BIG BANG or to our Creator?