IU: Our universe at home within a larger universe?

[bystander]

Our universe at home within a larger universe?
So suggests IU theoretical physicist's wormhole research
Indiana University News Room - 2010 April 06

Could our universe be located within the interior of a wormhole which itself is part of a black hole that lies within a much larger universe?

Such a scenario in which the universe is born from inside a wormhole (also called an Einstein-Rosen Bridge) is suggested in a paper from Indiana University theoretical physicist Nikodem Poplawski in Physics Letters B. ...

Poplawski takes advantage of the Euclidean-based coordinate system called isotropic coordinates to describe the gravitational field of a black hole and to model the radial geodesic motion of a massive particle into a black hole. ...

... "Because Einstein's general theory of relativity does not choose a time orientation, if a black hole can form from the gravitational collapse of matter through an event horizon in the future then the reverse process is also possible. Such a process would describe an exploding white hole: matter emerging from an event horizon in the past, like the expanding universe."

A white hole is connected to a black hole by an Einstein-Rosen bridge (wormhole) and is hypothetically the time reversal of a black hole. Poplawski's paper suggests that all astrophysical black holes, not just Schwarzschild and Einstein-Rosen black holes, may have Einstein-Rosen bridges, each with a new universe inside that formed simultaneously with the black hole.

"From that it follows that our universe could have itself formed from inside a black hole existing inside another universe," ...

This model in isotropic coordinates of the universe as a black hole could explain the origin of cosmic inflation

Radial motion into an Einstein–Rosen bridge

• Physics Letters B. Volume 687, Issues 2-3, 12 April 2010, Pages 110-113, doi: 10.1016/j.physletb.2010.03.029

We consider the radial geodesic motion of a massive particle into a black hole in isotropic coordinates, which represents the exterior region of an Einstein–Rosen bridge (wormhole). The particle enters the interior region, which is regular and physically equivalent to the asymptotically flat exterior of a white hole, and the particle's proper time extends to infinity. Since the radial motion into a wormhole after passing the event horizon is physically different from the motion into a Schwarzschild black hole, Einstein–Rosen and Schwarzschild black holes are different, physical realizations of general relativity. Yet for distant observers, both solutions are indistinguishable. We show that timelike geodesics in the field of a wormhole are complete because the expansion scalar in the Raychaudhuri equation has a discontinuity at the horizon, and because the Einstein–Rosen bridge is represented by the Kruskal diagram with Rindler's elliptic identification of the two antipodal future event horizons. These results suggest that observed astrophysical black holes may be Einstein–Rosen bridges, each with a new universe inside that formed simultaneously with the black hole. Accordingly, our own Universe may be the interior of a black hole existing inside another universe.

[bystander]

Our Universe Was Born in a Black Hole, Theory Says
Space.com - 27 April 2010

Our universe might have originated from a black hole that lies within another universe.

The idea centers on how matter and energy falling into a black hole could in theory come out a "white hole" in another universe. In such a situation, both the black hole and the white hole are mouths of an Einstein-Rosen bridge, popularly known as a wormhole.

With that in mind, theoretical physicist Nikodem Poplawski at Indiana University conjectured that when a black hole forms upon the collapse of a dying star, a universe is born at the same time from the white hole on the other side of the wormhole.

"Our universe could have itself formed from inside a black hole existing inside another universe," he said.

This idea has been suggested before, and now Poplawski has expanded on the thinking.

http://www.sciencedaily.com/releases/20 ... 172648.htm

[owlice]

You're just trying to make my head explode, aren't you?!!!

[bystander]

The Universe is Not a Black Hole
Discover: Cosmic Variance: 28 April 2010

People sometimes ask, “Is the universe a black hole?” Or worse, they claim: “The universe is a black hole!” No, it’s not, and it’s worth getting this one straight.

If there’s any quantitative reasoning behind the question (or claim), it comes from comparing the amount of matter within the observable universe to the radius of the observable universe, and noticing that it looks a lot like the relationship between the mass of a black hole and its Schwarzschild radius. That is: if you imagine taking all the stuff in the universe and putting it into one place, it would make a black hole the size of the universe. Slightly more formally, it looks like the the universe satisfies the hoop conjecture, so shouldn’t it form a black hole?

But a black hole is not “a place where a lot of mass has been squeezed inside its own Schwarzschild radius.” It is, as Wikipedia is happy to tell you, “a region of space from which nothing, including light, can escape.” The implication being that there is a region outside the black hole from which things could at least imagine escaping to. For the universe, there is no such outside region. So at a pretty trivial level, the universe is not a black hole.

You might say that this is picking nits, and the existence of an outside region is beside the point if the inside of our universe resembles a black hole. That’s fine, except: it doesn’t. You may have noticed that the universe is actually expanding, rather than contracting as you might expect the interior of a black hole to be. That’s because, if anything, our universe bears a passing resemblance to a white hole. Our universe (according to conventional general relativity) has a singularity in the past, out of which everything emerged, not a singularity in the future into which everything is crashing. We call that singularity the Big Bang, but it’s very similar to what we would expect from a white hole, which is just a time-reversed version of a black hole.

That insight, plus four dollars or so, will get you a grande latte at Starbucks. The spacetime solution to Einstein’s equation that describes a universe expanding from the Big Bang is very similar to the time-reversal of a black hole, but you don’t really learn much from making that statement, especially because there is no outside; everything you wanted to know was already there in the original cosmological language. Our universe is not going to collapse to a future singularity, even though the mass is enough to allow that to happen, simply because it’s expanding; the singularity you’re anticipating already happened.

Still, some folks will stubbornly insist, there has to be something deep and interesting about the fact that the radius of the observable universe is comparable to the Schwarzschild radius of an equally-sized black hole. And there is! It means the universe is spatially flat.

You can figure this out by looking at the Friedmann equation, which relates the Hubble parameter to the energy density and the spatial curvature of the universe. The radius of our observable universe is basically the Hubble length, which is the speed of light divided by the Hubble parameter. It’s a straightforward exercise to calculate the amount of mass inside a sphere whose radius is the Hubble length (M = 4πc³H^-3/3), and then calculate the corresponding Schwarzschild radius (R = 2GM/c²). You will find that the radius equals the Hubble length, if the universe is spatially flat. Voila!

Note that a spatially flat universe remains spatially flat forever, so this isn’t telling us anything about the universe now; it always has been true, and will remain always true. It’s a nice fact, but it doesn’t reveal anything about the universe that we didn’t already know by thinking about cosmology. Who wants to live inside a black hole, anyway?

[wonderboy]

I read in the metro all about white holes and found myself quite fascinated. It seemed like a good thing to post in here because it would spark debate. They say it answers a lot of theories about the universe that go unexplained, such as why we are speeding up (as regards expansion) rather than slowing down.

Basically, for those who didnt read the article or couldnt. a white hole is created when a massive star blows up (creating a blackhole) which then sucks in all the matter it can and deposits this (through a wormhole) into another universe as its seed. this matter then goes on to create planets, galaxies and stars and life etc etc. So for every blackhole, there is a whitehole and therfore another universe.

One argument states however, that if you go back through all the blackholes then you would eventually come back to nothing, and what was it that came before that nothing? some say this makes the theory fail, others would say maybe its god, I say, this is a potentially brilliant discussion just waiting to happen.

So get stuck in!



Paul

[wonderboy]

Our Universe Was Born in a Black Hole, Theory Says
Space.com - 27 April 2010

Our universe might have originated from a black hole that lies within another universe.

The idea centers on how matter and energy falling into a black hole could in theory come out a "white hole" in another universe. In such a situation, both the black hole and the white hole are mouths of an Einstein-Rosen bridge, popularly known as a wormhole.

With that in mind, theoretical physicist Nikodem Poplawski at Indiana University conjectured that when a black hole forms upon the collapse of a dying star, a universe is born at the same time from the white hole on the other side of the wormhole.

"Our universe could have itself formed from inside a black hole existing inside another universe," he said.

This idea has been suggested before, and now Poplawski has expanded on the thinking.

http://www.sciencedaily.com/releases/20 ... 172648.htm

My bad bystander, I never even knew this post existed. For the record though, I like the theory behind whiteholes!

Paul.

[makc]

this, however, poses the question, where the hell is our mother white hole?

[wonderboy]

We'll never find out of course, because the closer you get to the black hole the more expansion will speed up so there will be a point at which you will be going no further, but probably being pushed back.

Its an interesting theory though don't you think? It kind of makes sense.

Paul.

[makc]

so you mean our white hole is outside of observed universe? how convenient

[wonderboy]

so you mean our white hole is outside of observed universe? how convenient

Yes I do. Thats one of the "unanswerable" questions that the white hole theory answers which the big bang theory cannot. The rate of expansion is meant to slow down under the big bang, but if matter was being chucked out of a white hole continually then expansion would carry on much like the flow of a river. Mind you though, that would mean that there would be one direction of expansion, and doesn't take into account dark flows etc.

Its interesting is all im saying really.


Paul

[makc]

...one of the "unanswerable" questions that the white hole theory answers which the big bang theory cannot.

There is still the question where does all that matter originally come from. Like in "turtles all the way down" kind of story.

[wonderboy]

I did state that in my first post on the subject, that if you go all the way back then there is nothingness, what came before then? Its the same point that the big bang theory gets sketchy. But what if the Universe is infinite, and there is no end? it just keeps going like a duracell bunny.

Thing is though, we have pictures of blackholes from hubble etc, which are spewing out hot matter, these are not whiteholes because we can see the matter being ejected back into our own universe!

I think if this were to work, you would have to look at the centre of galaxies. They all (apparently) have supermassive blackholes at the centre, many solar masses bigger than our sun. what if our galaxy is feeding this blackhole slowly, thus creating a new universe by ejecting the matter from our galaxy through the whitehole?

Paul.

[The Code]

Very interesting post bystander. Thanks.

The universe is more of what we see. Just a lot bigger. Expansion, being quantum mechanics at work . Living in a giant black hole, very scary.

Mark

[wonderboy]

*looks outside* its not that scary if we are Mark? What would be scary would be getting sucked into another blackhole and ejected into some other alternate reality with no hope of getting back to our own.

Paul.

[The Code]

*looks outside* its not that scary if we are Mark? What would be scary would be getting sucked into another blackhole and ejected into some other alternate reality with no hope of getting back to our own.

Paul.

You been watching to much SG-1.

But on a serious note. Would not being inside a giant black hole, give a good reason for a Dark Flow?

Mark

[Chris Peterson]

But on a serious note. Would not being inside a giant black hole, give a good reason for a Dark Flow?

I'd say no, simply because there's not a shred of theory associated with black holes that describes what happens to matter inside a black hole. So amongst other unknowns, it can't be determined if internal matter exists outside a singularity, or if it can move at all.

[The Code]

But on a serious note. Would not being inside a giant black hole, give a good reason for a Dark Flow?

I'd say no, simply because there's not a shred of theory associated with black holes that describes what happens to matter inside a black hole. So amongst other unknowns, it can't be determined if internal matter exists outside a singularity, or if it can move at all.

If in fact we live inside a singularity. But would be some plausible explanation for nothing filling the universe and causing expansion.

[bystander]

Why Our Universe Must Have Been Born Inside a Black Hole
Technology Review | the physics arXiv blog | 13 July 2010

A small change to the theory of gravity implies that our universe inherited its arrow of time from the black hole in which it was born.

"Accordingly, our own Universe may be the interior of a black hole existing in another universe." So concludes Nikodem Poplawski at Indiana University in a remarkable paper about the nature of space and the origin of time.

The idea that new universes can be created inside black holes and that our own may have originated in this way has been the raw fodder of science fiction for many years. But a proper scientific derivation of the notion has never emerged.

Today Poplawski provides such a derivation. He says the idea that black holes are the cosmic mothers of new universes is a natural consequence of a simple new assumption about the nature of spacetime.

Poplawski points out that the standard derivation of general relativity takes no account of the intrinsic momentum of spin half particles. However there is another version of the theory, called the Einstein-Cartan-Kibble-Sciama theory of gravity, which does.

This predicts that particles with half integer spin should interact, generating a tiny repulsive force called torsion. In ordinary circumstances, torsion is too small to have any effect. But when densities become much higher than those in nuclear matter, it becomes significant. In particular, says Poplawski, torsion prevents the formation of singularities inside a black hole.

That's interesting for a number of reasons. First, it has important implications for the way the Universe must have grown when it was close to its minimum size. ...

Cosmology with torsion - an alternative to cosmic inflation

• arXiv.org > astro-ph > arXiv:1007.0587 > 04 July 2010

[Ann]

Interesting.

Some years ago a charismatic Swedish lecturer, Hans-Uno Bengtsson, said in a lecture that I listened to, that our universe has emerged out of a black hole. He certainly didn't say, however, that our universe was a black hole.



Hans-Uno Bengtsson, Professor of Physics who spent some years teaching at UCLA.



Hans-Uno Bengtsson was an amateur aviator and flew his own Piper Cub plane from 1944.



In 2007, Hans-Uno Bengtsson died quite suddenly at the age of 54. At his funeral, some of his aviator friends flew their own Piper Cub planes over the cathedral where the funeral was taking place in a "missing man" formation.

Anyway, I have never forgotten what Hans-Uno Bengtsson said at that lecture that I listened to, that our universe has emerged out of a black hole in another universe.

Ann

[geckzilla]

Going for that Beaker hairstyle, eh... Not quite orange enough!

Edit: Whoops, apologies for the thread derailment... but that guy's hair can't go without comment. And now, return to our regularly scheduled programming... if Art can resist a long article about Muppets.

[BMAONE23]

His hair more resembles that of Harry Potter as described in the books than was depicted in the movies

[bystander]

Interesting.

Some years ago a charismatic Swedish lecturer, Hans-Uno Bengtsson, said in a lecture that I listened to, that our universe has emerged out of a black hole. He certainly didn't say, however, that our universe was a black hole.
...
Anyway, I have never forgotten what Hans-Uno Bengtsson said at that lecture that I listened to, that our universe has emerged out of a black hole in another universe.

Ann

I think that is what Poplawski is saying, that our universe emerged from a black hole in another universe. It doesn't seem to be a very popular theory. See: http://asterisk.apod.com/vie ... 31#p120331

[bystander]

The Universe Is Not In A Black Hole
Astronomy Without A Telescope
Universe Today | 31 July 2010

[url=http://en.wikipedia.org/wiki/Frame-dragging][b]Frame-dragging:[/b][/url] [b]Does a spinning massive object wind up spacetime?[/b] [b][i](Credit: J Bergeron / Sky and Telescope)[/i][/b] [url=http://apod.nasa.gov/apod/ap971107.html][b][i]APOD: 1997 Nov 07[/i][/b][/url]

---

It has been reported that a recent scientific paper delivers the conclusion that our universe resides inside a black hole in another universe – which is not exactly what was concluded. Also, that work delivers some more interesting, or at least more tangible, ideas about how our early universe may have unfolded.

The Einstein-Cartan-Kibble-Sciama (ECKS) theory of gravity – claimed as an alternative to general relativity theory, although still based on Einstein field equations – seeks to take greater account of the effect of the spin of massive particles. Essentially, while general relativity has it that matter determines how spacetime curves, ECKS also tries to capture the torsion of spacetime, which is a more dynamic idea of curvature – where you have to think in terms of twisting and contortion, rather than just curvature.

Mind you, general relativity is also able to deal with dynamic curvature. ECKS proponents claim that where ECKS departs from general relativity is in situations of very high matter density – such as in black holes. General relativity suggests that a singularity (with infinite density and zero volume) forms beyond a black hole’s event horizon. This is not an altogether satisfying result since the contents of black holes do seem to occupy volume – more massive ones do have larger diameters than less massive ones – so general relativity may just be inadequate at dealing with all aspects of black hole physics.

ECKS theory attempts to step around the singularity problem by proposing that an extreme torsion of spacetime, resulting from the spin of massive particles compressed within a black hole, prevents a singularity from forming. Instead the intense compression increases the intrinsic angular momentum of the matter within (i.e. the spinning skater draws arms in analogy) until a point is reached where spacetime becomes as twisted, or as wound up, as it can go. From there, expansion (i.e. unwinding) of spacetime occurs – and voila new baby universe.

But the new baby universe can’t be born and expand in the black hole. Remember this is general relativity. From any frame of reference outside the black hole, the events just described cannot happen. Clocks seem to slow to a standstill as they approach a black hole’s event horizon. It makes no sense for an external observer to suggest that a sequence of events is taking place over time inside a black hole. If it remained in our universe, the potential baby universe would have no time to play with before the black hole evaporated – even though from an external frame of reference that might be a googol years later.

Instead, it is proposed that the birth and expansion of new baby universe proceeds along a separate branch of spacetime via the black hole acting as an Einstein-Rosen bridge (i.e. a wormhole).

If correct, it’s a turtles on turtles solution and we are left to ponder the mystery of the origin of the multiverse – or at least the primeval universe which first formed black holes from which all subsequent universes originate.

What’s just as interesting about ECKS is that the torsion concept provides an alternative explanation to cosmic inflation. Matter and energy crunched within a black hole should achieve a state of isotropy and homogeneity (i.e. no wrinkles) – and when it expands into its hypothetical wormhole, it does so via the unwinding of the spacetime torsion that was built up in the black hole. So you have an explanation for why a universe expands – and why it’s so isotropic and homogenous.

<-- Previous

[bystander]

Hans-Uno Bengtsson, Professor of Physics who spent some years teaching at UCLA.

Looks kind of like Stephen King.

[makc]

Hans-Uno Bengtsson, Professor of Physics who spent some years teaching at UCLA.

His hair more resembles that of Harry Potter as described in the books than was depicted in the movies

My 1st thought was