Time Dimension To Become Space-like

KentuckyFC writes "The Universe is about to flip from having three dimensions of space and one of time to having four dimensions of space. That's the conclusion of a group of Spanish astrophysicists who have calculated that observers inside such a Universe would see it expanding and accelerating away from them just before the flip (abstract, full paper pdf on the physics arXiv). 'We show that regular changes of signature on brane-worlds in AdS bulks may account for some types of the recently fashionable sudden singularities. Therefore, the fact that the Universe seems to approach a future sudden singularity at an accelerated rate of expansion might simply be an indication that our braneworld is about to change from Lorentzian to Euclidean signature. Both the brane and the bulk remain fully regular everywhere.'" Update: 10/09 16:06 GMT by Z : A few readers have written in to point out that the article is not peer-reviewed; your mileage may vary.

Mayan Calender

[andyh3930 (605873)]

So that's whats going to happen when the Mayan calender rolls over in 2012.

Re:Mayan Calender

[dark404 (714846)]

There will be a patch to update the calendar software to granite instead of sand stone, this will push the calendar into 4096.

Assumptions

[camperdave (969942)]

Change requires time. It's a logical paradox.

You're assuming that there is only one time dimension. But actually, from a non-linear, non-subjective viewpoint, it's more like a big ball of wibbly-wobbly, timey-wimey... stuff.

Thank you, Doctor

[Prototerm (762512)]

Don't blink, don't turn away, don't close your eyes, and whatever you do, don't blink!

(for those of you who didn't recognize the Doctor Who quote in the parent, turn in your geek badge!)

Re:Assumptions

[flyingsquid (813711)]

All I know is, my boss has now declared that our fifteen-minute breaks are to be replaced by 15-centimeter breaks. Asshole.

Time speeding up

[Skevin (16048)]

When I first heard that the rate of the universe's expansion was actually accelerating, I came up with a weird hypothesis after a few days...

Time in our frame of reference is slowing down.

The only way that seemed possible was if we were traveling at speeds close to c, but that didn't sound feasible since we were observing objects that were moving away from us, in all directions. Then another weird thought occurred to me...

Our observed universe is self-contained within the event horizon of a giant black hole.

We're closer to the singularity, and accelerating towards it faster than objects closer to the edge of the event horizon. Time will move slower for us, and far away objects will appear to speed up. An outside observer (if such a thing could possibly exist) would perceive our universe as shrinking, but in our current frame of reference, we still think of it as expanding.

One other observation that lends to this possibility is the fact that we have not seen evidence of other "Big Bangs" or other "Universes". If the Big Bang happened once, shouldn't it be a repeatable occurrence in the limitless void of space?

Okay, that's my rant. You can slap the straitjacket on me now and ship me off to the funny farm.

Solomon Chang

Re:Time speeding up

[ObsessiveMathsFreak (773371)]

Okay, that's my rant. You can slap the straitjacket on me now and ship me off to the funny farm.

Or give you a Phd in theoretical physics. It's all good.

Re:Time speeding up

[ObsessiveMathsFreak (773371)]

IS there a difference?

It's possible to actually get certified as sane if you're sent to the funny farm.

Re:Time speeding up

[addbo (165128)]

Interesting when I took astronomy in University I had the same hypothesis that the Universe itself is a black hole.

One of the unintuitive properties of a black hole is that as mass increases the average density inside the Schwarschild radius decreases... even though the radius itself increases. Anyways as Mass goes to infinity, Density inside the Schwarschild radius goes to Zero and of course the Radius goes to infinity.

The radius of the known Universe along with the mass that is hypothesized almost satisfy the Schwarschild radius equation and is only off by a factor of 2 or 3.(Which isn't much in Astronomy)

Re:Time speeding up

[dissy (172727)]

The big-bang didn't happen sometime in the limitless void of space, the big-bang was the creation of the space-time continuum itself.

Not according to current brane and bulk theories. In them, time and space existed forever, and still do. The big bang is just a massive release of energy, that reorders the energy and matter within our brane in a way that appears everything is moving away from that 4d point.

One suggestion was that two branes within the bulk colided, and all that energy that has to go somewhere goes into a big bang in a 4d brane (the bulk is either 10 or lately 11 dinentions while we are just in 4)

If those theories are correct, both time and space existed before the big bang, and also at some point in the future our brane will collide with another again and cause another big bang. This happens through out all the branes at different times and repeats forever.

Note that I word my post as if "this is", when it should be pointed out that my wording is this way "if these theories are right", so please take it as such.

Re:M-Theory is bad science

[fyngyrz (762201)]

M-Theory was the brain child of a bunch of mathematicians

M-Theory was the brane child of a bunch of mathematicians

[tips hat]

Well, I for one welcomed our five dimentional

[crovira (10242)]

overlords.

Breaking "time's arrow" will really fuck with our verb tenses.

But I worried about that tomorrow...

Re:Eternal Life

[ConceptJunkie (24823)]

That means no movement and no thought.

Don't look now, but it's already happened in Washington, D.C.

Ode to the new way

[fyngyrz (762201)]

Oh, I'm living in a tesseract,
a four dimensional box.
It's bigger on the inside,
what why my four-space rocks!
When you get on the inside,
the outside becomes the in,
Dimensionally speaking,
it's all about the spin.

E=MC^2

[jshriverWVU (810740)]

If only Einstein was around to see it :)

Re:E=MC^2

[mikael (484)]

He's spinning in his grave - in a quantum mechanical way of course.

Re:E=MC^2

[bar-agent (698856)]

He's spinning in his grave - in a quantum mechanical way of course.

Would that be spin-up or spin-down?

Re:E=MC^2

[HTH NE1 (675604)]

Would that be spin-up or spin-down?

Both, obviously.

I find that strangely charming.

My advice

[Weaselmancer (533834)]

Avoid poetry, coastal cities, and the Catskill mountains. Seriously. [wikipedia.org]

I wasn't expecting that...

[by Anonymous Coward]

Nobody Expects the Spanish Astrophysicists! In fact, our two main weapons are theory and telescopes, theory and telescopes, and an insane amount of genius, wait that's three, our three main weapons are...

But what does that mean?

[downix (84795)]

If time becomes space-like, what would that mean for us? Would we be able to transverse time as easily as space? Would time itself become irrelevent as we could look "forwards"? Will the cubs win the world series? These important questions have to be answered!

Re:

[caramelcarrot (778148)]

Physics as we experience it will go to shit, since much of the base derivations are a consequence of a non-spacelike time.

ow ow my brane hurts!

[by Anonymous Coward]

..maybe if I wait a few feet it'll feel better

Re:Not just what, but when?

[Basehart (633304)]

I'm guessing some time in the future.

Re:

[Anonymous Monkey (795756)]

No, not at some time in the future. At some POINT in the future. If time is becomes a detention of physical space then future and past will be like left and right. I could never tell my left from my right as a kid.

Re:Not just what, but when?

[$RANDOMLUSER (804576)]

I'm guessing some time in the future.

You missed the whole point. Some place in the future.

Re:Not just what, but when?

[timster (32400)]

Silly... obviously the question is NOT "When will this happen?" Without time there is no "when", and no "happen", and no "will". Only "this".

Should this research be correct, the only question left will be: "This?" Now and always and forever, this?

Re:Not just what, but when?

[Dr. Eggman (932300)]

In the future, time will become very confusing...

Dark Helmet: What the hell am I looking at? When does this happen in the movie?
Sandurz: Now, you're looking at now, sir. Everything that happens now is happening now.
Dark Helmet: What happend to then?
Sandurz: We passed then.
Dark Helmet: When?
Sandurz: Just now. Were at now, now.
Dark Helmet: Go back to then!
Sandurz: When?
Dark Helmet: Now.
Sandurz: Now?
Dark Helmet: Now!
Sandurz: I can't.
Dark Helmet: Why?
Sandurz: We missed it.
Dark Helmet: When?
Sandurz: Just now.
Dark Helmet: When will then be now?
Sandurz: Soon.
Dark Helmet: How soon?

Re:Not just what, but when?

[ArieKremen (733795)]

The real question is not "when is this expected to happen?", but where? I think it already happened on the NJ turnpike a long time ago

Re:But what does that mean?

[inviolet (797804)]

> Would we be able to transverse time as easily as space?
Yes!

> Would time itself become irrelevent as we could look "forwards"?
Yes!

In "Slaughterhouse Five", Vonnegut wrote about creatures who perceived time as a geometric dimension. They could perceive their entire lives as a wide landscape, stretching from past to present to future... and they could move freely within it, to relive the better moments and fast-forward over the unpleasant ones.

One of the implications that these creatures could see, but which we could not, is that the universe can only play out one way. Whatever happens, has always happened, and always will happen, it is unavoidable. The creatures could see their future with absolute certainty, and so they knew that choice is an illusion (or, in my understanding, a mis-connotated word that belongs in the realm of epistemology rather than of metaphysics).

In any case, if the universe experiences this sort of "signature change", then we'll never know it. Consciousness will abruptly cease, like a paused DVD player or a saved Diablo game, waiting forever for time to resume. But, a new sort of consciousness could arise, to which physical movement is the equivalent of temporal progression. Somehow, if it could gather information and then ruminate upon it, by means of movement rather than time, it could become self-aware.

Re:But what does that mean?

[jeffasselin (566598)]

The existence of 3 dimensions of time is one of the suggestions of quantum gravity.

Also, why does time seem to flow into a single direction? Most of the equations of physics work fine both ways, but time only appears to flow in a single direction, only its "pace" changes. The best explanation is that there's a breaking of symmetry, a process which for some reason only occurs in one direction of the time dimension(s). The only such process we can observe at this time is entropy. In a closed system, it always increases, it can never decrease. So entropy seems to be linked to time in some intricate way, or maybe it's actually an extra time dimension linked to the first in some way. So what happens if time changes into a space dimension? What does that even MEAN? The only significant difference between time and space is that single direction in which time flows, so does it mean the second law of thermodynamics will stop applying? The flow of entropy will reverse or break its link to the time dimension? This would not necessarily be so "bad" but it would completely break down most of the laws of physics that depend on this phenomenon, thus destroying the universe, no?

Re:But what does that mean?

[ultranova (717540)]

The only such process we can observe at this time is entropy. In a closed system, it always increases, it can never decrease.

In a closed system entropy can and does decrease from time to time. It is simply much more likely to increase, due to there being more possible states with high entropy than there are states with low entropy in known physical systems, and the likelihood of it decreasing in a given period decreases sharply as the complexity of the system grows. It never goes to zero, thought.

A classical example is a box with two separate gasses, initially separated by a dividing wall. If the wall is removed, the gasses will mix, eventually spreading equally to every part of the box. However, suppose that the box only contains a single molecule of both gasses. It is certainly possible, and even likely, that both molecules happen to be at their initial side of the box, and both gassed therefore separated back to their own sides, at some future point. Add another molecule to both gassed, and you'll have to wait a bit longer for all four to be at their initial sides, but still not too long. A third molecule, and it takes longer still, then fourth, fifth and so on.

The more molecules you add, the longer you'll have to wait. However, no matter how many molecules there are in the box, given a long enough time, the gasses will separate, simply due to random motion of the molecules happenign to take all the molecules of one gas to one side of the box at the same time, and all the molecules of the other gas to the other side at the same time.

It will take almost, but not quite, forever, but that's a far cry from "never".

Plagarism!

[Jeremiah Cornelius (137)]

I first read this theory in Oolong Caloophid's seminal work: "Where God Went Wrong."

More of this is elaborated in his development of these themes: "Some More of God's Greatest Mistakes," and "Who Is This God Person Anyway?".

This can mean but one thing

[Arthur B. (806360)]

Jeebus will return ! Clean your browsing history and cache.

the intersection of mathematics and cosmology

[circletimessquare (444983)]

where the theories and calculations of the brightest brains in the room become indistinguishable from the random brainfarts of two stoners sitting on a smelly couch in a dorm room at 4:20 AM

Peer review

[MillionthMonkey (240664)]

The peers are going to review this a few centimeters from now; give them time.

Re:

[eclectro (227083)]

You don't need peer review if you have enough branes.

"... about to ..."

[dpilot (134227)]

So dpilot was talking with God, and God said, "To Me, a minute is like a million years, and a million years are like a minute." So dpilot said, "In a that vein, is a penny like a billion dollars, and a dollars like a penny?" God replied, "You've got it." Which led dpilot to ask of God, "Can you spare a penny?" "Sure," said God, "in just a minute..."

When you say "about to" in sports, something generally happens pretty fast.
When you say "about to" in geology, something generally happens pretty slow.
Generally speaking, saying "about to" in cosmology is to geology as geology is to sports.

But not always. At some points in time, the volcano under Yellowstone does go off. Likewise, supernovas happen, and perhaps brane changes too. But to say "about to" or "soon" is just meaningless to human scales of time.

Define "about to"?

[WibbleOnMars (1129233)]

I'd like to know how they define "about to flip".

Are we talking about something they see as imminent -- could happen at any moment?
Or are we talking about geological time scales -- it'll happen in a few hundred thousand years, give or take?
Or do they mean cosmological scales -- where 'about to happen' means somewhere in the next ten or twenty million years?

Or is the whole question of when a silly thing to ask, given that they're talking about the end of time as sequential/chronological?

All you D & D players

[Ilan Volow (539597)]

Get that last game in before your game stops working with your newly created 144-sided dice.

Lorentzian to Euclidian transformations...

[jnaujok (804613)]

All this talk about time becoming a spatial dimension and realities collapsing is making my brane hurt.

Yeah, I said it.

Mileage?

[TheRaven64 (641858)]

Update: 10/09 16:06 GMT by Z : A few readers have written in to point out that the article is not peer-reviewed; your mileage may vary.

So may your yearage, presumably.

Hope not.

[mattr (78516)]

I knew 3 answers to the Fermi Paradox. Either intelligence quickly builds into quiet-looking shells like in Charlie Stross' Accelerando, or by virtue of being conscious we humans have somehow carved out a light cone or domain excluding other intelligences, some wierd cocoon: it is impossible physically to communicate because other domains have other physics. There's a neat scifi story about that too. The third is a land mine in physics, waiting for young civilizations to liberate enough power to fry them. Heinlein did that one, it's a nasty one. Now a fourth: the universe really is out to get us. Not just out to get aggressive monkeys that want to learn high-energy physics, but even to the point of making a state flip ever so often. I think this last one (today's news) is pretty unlikely to happen any time soon but nevertheless it is a future killer, something harder to understand than the burning out of the stars in the far future. None of these are very nice ideas but I hope some physicists will step up to answering what the latest theory says about when it might happen and whether it could operate on a patchwork basis, killing other civilizations while our planet was still cooling.

Are there any /. editors with physics degrees?

[davidoff404 (764733)]

Unfortunately, while the ArXiv is where important results are first published by working physicists, it's also a place where an increasing amount of junk papers are posted. For those who are interested, this is an example of just such a junk paper as it amounts to nothing more than a fancy way to produce a (parameterized) Wick rotation in a braneworld model.

Of course, let's not even mention the fact that they're proposing that braneworlds and AdS are reasonable approaches to physics...

My crude guess

[khallow (566160)]

It appears to me that this is a purely mathematical result. They are basically saying that an anti-de sitter bulk, the interior of anti de Sitter (AdS) space which is a constant negatively curved (or constant positive cosmological constant) with one time-like dimension (Lorentzian space) can be glued to a euclidean space smoothly along the boundary of the two spaces. Classically, this is of little relevance since time-based trajectories would stop at the boundary (either take infinite time to arrive or the system would "rip" itself apart at the boundary). Instead there could be (though not addressed in the paper) observable quantum effects from having something past the boundary even if it is purely spatial. Space-time states might extend over the boudary into this other space. So you might end up with the strange situation where parts of the universe are interacting beyond the end of time.

This paper doesn't tell you whether that occurs or not. But it does indicate that it is possible for quantum systems to have both Lorentzian and Euclidean space components seamlessly connected.

Consequences

[xPsi (851544)]

Ok, as others have pointed out, this "paper" is not peer reviewed. I want to make it clear that I don't personally feel slashdot is the place to debate random physics papers on the arXiv. But, being slashdot, I will ignore my own pleas for sanity. What would be the physical consequences of time suddenly becoming space-like? First, on most mesoscopic scales in our everyday life, time already appears like a spatial dimension. Newton certainly thought so and our (incorrect) intuition tells us this is the case. The degree to which special and general relativity play a role in your everyday life is a measure of how "time-like" time feels. Probably not much. Nevertheless, if time suddenly physically became space-like, physicists all over the world would know it right away. All the weird stuff in relativity like time dilation and space contraction and so on, comes from time having an opposite metric sign as space. These effects all go away if time is space-like. For example, in a typical advanced undergraduate physics lab, you might measure the lifetime of a muon that is sitting in the lab as opposed to one that is crashing down from the sky. The one coming from above (at a large fraction the speed of light) lives longer in the frame of the ground because of time dilation. Easily verified in an afternoon. But I guess no more (at least after next Thursday or whenever this is supposed to happen). Similarly, all the special relativity equations required to perform basic momentum, energy, and lifetime calculations at colliders like Fermilab, CERN, and Brookhaven would suddenly stop working. That would be a big deal and it wouldn't be a subtle thing. IMHO, it makes for great science fiction, but I'm not sure where these guys are going with it.

Re:So. . . .

[Jeremiah Cornelius (137)]

"Oh, that was easy," says Man, and for an encore goes on to prove that black is white and gets himself killed on the next zebra crossing.

Re:

[pclminion (145572)]

Isn't "time" only subtlety different from a physical dimension?

This phrasing suggests that time is not a physical thing. Given that the variable "t" occurs in practically all dynamic equations of physics, I'd have to disagree with the assertion that time isn't physical.

Re:So how does this affect us?

[Qzukk (229616)]

The other one was about a kid who befriends a neighbor working in 4-D stuff. The kid (because he's young and has an open mind or something) learns to move about in that dimension as well, and communicate with creatures living in other dimensions. Don't remember the title of that one, thoguh.

I believe that's The Boy Who Reversed Himself [amazon.com]. I remember having read that when I was in highschool.

Re:Explanation?

[xPsi (851544)]

Lets say I told you we had two spatial dimensions. You would imagine a plane with perpendicular x-y axes everyone knows and loves. If I asked you to draw the set of points that were equidistant from the origin, you would probably assume the geometry was Euclidian and would probably instinctively draw a circle (a good guess!). It is commonplace to hear "time is the fourth dimension." As first pass to visualize this, you might try to draw a two dimensional space-time plot: an x axis and a perpendicular time axis in a plane. If I then asked you to draw all the points equidistant from the origin, you would probably again draw a circle in this x-t plane. It seems to make sense, but is only true of time is a "space-like" dimension like "y" in the x-y plane. This is way Newton thought of things and it seems to be what the authors of the paper are advocating. But, unbeknownst to some people who cite "time as the fourth dimension," according to the theory of relativity, the set of equidistant points from the origin on a x-t graph would actually be hyperbole, not circles. This is because in relativity space-time is a Minkowski geometry, not Euclidian. All the weird stuff in special relativity like time dilation and length contraction come about because of this weird geometry. In fancier language, time has an opposite sign than space in the metric. The metric determines how distances are calculated in a given geometry. If time has the same sign as space in the metric, then space-time becomes Euclidian and one would say that time was a space-like. The article is probably extra confusing to non-physics people because most probably didn't know time wasn't space-like to begin with.