Time likely to end within 5 billion years, physicists calculate

Oct 01, 2010 by Lisa Zyga report
This figure shows two different cutoff scenarios showing how time could end. Image credit: Raphael Bousso, et al.

(PhysOrg.com) -- As far as astrophysicists can tell, the universe is expanding at an accelerating rate, and will likely continue to do so indefinitely. But now some physicists are saying that this theory, called eternal inflation, and its implication that time is endless pose a problem for scientists calculating the probability of any event occurring. In a recent paper, they calculate that time is likely to end within the next 5 billion years due to some type of catastrophe that no one alive at the time will witness.

The physicists, Raphael Bousso from the University of California, Berkeley, and coauthors have posted a paper detailing their theory on arXiv.org. In their paper, they explain that in an eternal universe, even the most unlikely events will eventually occur -- and not only occur, but occur an infinite number of times. Since probabilities are defined in terms of the relative abundance of events, there would be no point in determining any probabilities because every event would be equally likely to happen.

"If it does occur in Nature, eternal inflation has profound implications," write Bousso and coauthors in their paper. "Any type of event that has nonzero probability will happen infinitely many times, usually in widely separated regions that remain forever outside of causal contact. This undermines the basis for probabilistic predictions of local experiments. If infinitely many observers throughout the universe win the lottery, on what grounds can one still claim that winning the lottery is unlikely? To be sure, there are also infinitely many observers who do not win, but in what sense are there more of them? In local experiments such as playing the lottery, we have clear rules for making predictions and testing theories. But if the universe is eternally inflating, we no longer know why these rules work.

"To see that this is not merely a philosophical point, it helps to consider cosmological experiments, where the rules are less clear. For example, one would like to predict or explain features of the CMB [cosmic microwave background]; or, in a theory with more than one vacuum, one might wish to predict the expected properties of the vacuum we find ourselves in, such as the Higgs mass. This requires computing the relative number of observations of different values for the Higgs mass, or of the CMB sky. There will be infinitely many instances of every possible observation, so what are the probabilities? This is known as the 'measure problem' of eternal inflation."

One solution to this problem, the physicists explain, is to conclude that will eventually end. Then there would be a finite number of events that occur, with the improbable events occurring less often than the probable events.

The timing of this "cutoff" would define the set of allowed events. Thus, the physicists have attempted to calculate the probability of when time will end given five different cutoff measures. In two of these scenarios, time has a 50% chance of ending within 3.7 billion years. In two other scenarios, time has a 50% chance of ending within 3.3 billion years.

In the fifth and final scenario, the timescale is very short (on the order of the Planck time). In this scenario, the scientists calculated that "time would be overwhelmingly likely to end in the next second." Fortunately, this calculation predicts that most observers are "Boltzmann babies" who arise from quantum fluctuations in the early universe. Since most of us are not, the physicists could rule this scenario out "at a high level of confidence."

What would the end of time be like for observers around at the time? As the physicists explain, the observers would never see it coming. "The observer will necessarily run into the cutoff before observing the demise of any other system," the scientists write. They compare the boundary of the time cutoff to the horizon of a black hole.

"The boundary ... can be treated as an object with physical attributes, including temperature," the authors write in their paper. "Matter systems that encounter the end of time are thermalized at this horizon. This is similar to an outside observer's description of a matter system falling into a black hole. What is radically new, however, is the statement that we might experience thermalization upon crossing the black hole horizon." Yet the thermalizing "matter system" would still not notice anything unusual when crossing this horizon.

For those who feel uncomfortable about time ending, the physicists note that there are other solutions to the measure problem. They don't claim that their conclusion that time will end is correct, only that it follows logically from a set of assumptions. So perhaps one of the three assumptions underlying the conclusion is incorrect instead.

The first assumption is that the is eternally inflating, which is a consequence of general relativity and well supported by the experimental evidence so far observed. The second assumption is that the definition of probability is based on the relative frequency of an event, or what the scientists call the assumption of typicality. The third assumption is that, if spacetime is indeed infinite, then the only way to determine the probability of an event is to restrict one's attention to a finite subset of the infinite multiverse. Some other have already looked into alternatives to this third assumption.

Whatever happens in the next 3.7 billion years, Bousso and his coauthors' paper will likely be spurring a variety of reactions in the near future.

Explore further: Could 'Jedi Putter' be the force golfers need?

More information: Raphael Bousso, et al. “Eternal inflation predicts that time will end.” arXiv:1009.4698v1
via: The Physics ArXiv Blog

Related Stories

Physicists Calculate Number of Parallel Universes

Oct 16, 2009

(PhysOrg.com) -- Over the past few decades, the idea that our universe could be one of many alternate universes within a giant multiverse has grown from a sci-fi fantasy into a legitimate theoretical possibility. ...

Researchers show that the big bang was followed by chaos

Sep 07, 2010

(PhysOrg.com) -- Seven years ago Northwestern University physicist Adilson E. Motter conjectured that the expansion of the universe at the time of the big bang was highly chaotic. Now he and a colleague have ...

Recommended for you

Could 'Jedi Putter' be the force golfers need?

Apr 18, 2014

Putting is arguably the most important skill in golf; in fact, it's been described as a game within a game. Now a team of Rice engineering students has devised a training putter that offers golfers audio, ...

Better thermal-imaging lens from waste sulfur

Apr 17, 2014

Sulfur left over from refining fossil fuels can be transformed into cheap, lightweight, plastic lenses for infrared devices, including night-vision goggles, a University of Arizona-led international team ...

User comments : 96

Adjust slider to filter visible comments by rank

Display comments: newest first

CTD1
1.6 / 5 (13) Oct 01, 2010
The idea of disappearance of time is not quite new

http://www.dailyg...yes.html

and it's even attributed to string theory:

"Our calculations show that we would think that the expansion of the universe is accelerating," says Prof Senovilla. The theory bases it’s idea on one particular variant of superstring theory, in which our universe is confined to the surface of a membrane, or brane, floating in a higher-dimensional space, known as the "bulk". In billions of years, time would cease to be time altogether.

This model actually may be time symmetric in analogy with ripple spreading at the water surface - they're dispersing at both large, both small scales. For example, dark energy/quintessence models suggests frozen universe before 11.5 billion years or so.

http://www.futuri...universe
dtxx
1 / 5 (3) Oct 01, 2010
Why can't expansion asymptotically approach infinity, allowing a permanent margin where highly unlikely events still have a chance of not happening?
ShotmanMaslo
3.5 / 5 (16) Oct 01, 2010
Excuse me, but, I dont see how infinite time poses problem for probabilities. Yes, given infinite time, every event with nonzero probability will happen infinite times, but not all infinities are the same - more probable events will still happen more times than less probable. Infinities do not have to be equal. Its like comparing infinite number of natural numbers with infinite number of rational (and irrational) numbers - both counts are infinite, but one is still greater than the other.

Can someone explain where is teh problem?
iWander
not rated yet Oct 01, 2010
Infinities do not have to be equal. Its like comparing infinite number of natural numbers with infinite number of rational (and irrational) numbers - both counts are infinite, but one is still greater than the other.


Bloody Cantor...the guy was crazy! An infinity is the perfect cancellation, it does not exist. If it did exist, there would not be multiple infinities, but a single infinity viewed from different perspectives. As you observe differences, we're not in an true infinity, but certain dimensions may have apparent infinite length. I say apparent as they will do what they do, until it reaches the end.

The article is saying that with an infinite amount of events, one of those events is bound to end time. As time passes, the probability of that happening increases.

The universe could end with the various forces and fields coming apart, just as they came together.

Everything ends, but it may mean something new will appear but as we are bound to time, we're dead.
Skeptic_Heretic
2.1 / 5 (8) Oct 01, 2010
Excuse me, but, I dont see how infinite time poses problem for probabilities.
Well it doesn't until you couple it with observation. With infinite time you must be able to violate causality and the various stability that classical mechanics brings through the accuracy of quantum description.

Basically, if time is infinite, we should see reverses in entropy as they aren't restricted, simply unlikely.

That's the problem, we're not seeing enough weird stuff. Now I don't agree with the problem, I think it's philosophical ramblings based on a lack of understanding.
both counts are infinite, but one is still greater than the other.
No, you're not understanding the concept of infinity. There is no greater or lesser when comparing infinite quantities.
frajo
5 / 5 (6) Oct 01, 2010
Goodness, another brew of multiverse metaphysics.

One underlying assumption they forgot to mention is the inflation hypothesis itself.
One conceptual error is the mixing up of the inflation term of the inflation hypothesis (the nearly instantaneous expansion shortly after the BigBang) with the contemporary accelerating expansion of the universe which is a conclusion based mainly on SN Ia observations and the hypotheses of their inner workings.

I don't see any falsifiable predictions around here.
We need better SN Ia models.
HoboWhisperer
3 / 5 (4) Oct 01, 2010
No, you're not understanding the concept of infinity. There is no greater or lesser when comparing infinite quantities.


... In fact there is.

set of integers from 0 to infinity is provably larger than the set from 1 to infinity. They can be subtracted, resulting in a difference of 1.
Skeptic_Heretic
1 / 5 (5) Oct 01, 2010
set of integers from 0 to infinity is provably larger than the set from 1 to infinity. They can be subtracted, resulting in a difference of 1.
No they can't. Those two sets are not infinite as they have a boundary condition. You also do not understand infinity. With no upper boundary, there is no conclusion to the set, meaning no fixed content. You cannot apply a comparision between two infinite sets and receive an end result. That is what infinity is.
kasen
5 / 5 (4) Oct 01, 2010
To see that this is not merely a philosophical point, it helps to consider cosmological experiments, where the rules are less clear.


Right. You want less clarity to make something look less philosophic.

This seems to me like a misunderstanding and misuse of the mathematical infinity symbol and statistics. They did say they might be wrong, which is commendable, but won't appease the press. I am not looking forward to reading about this in the local tabloids.
Noumenon
4.4 / 5 (57) Oct 01, 2010
...The fourth assumption is that Time is a physical entity existing independently of it's application in relating observations, .... that it's not merely a component of the a-priori conceptual framework in which phenomenal reality is comprehended. Dark energy has never been observed, but a physical time 'particle' has also never been observed.
HoboWhisperer
4 / 5 (4) Oct 01, 2010
@ Skeptic Heretic

Read up on Georg Cantor's Set Theory.
frajo
4 / 5 (3) Oct 01, 2010
There is no greater or lesser when comparing infinite quantities.
You are right, but going a little bit OT we can prove that the set of real numbers has a higher cardinality, aleph-one or higher, than the set of natural numbers has, aleph-null.
Noumenon
4.4 / 5 (56) Oct 01, 2010
While the space-time Interval is invariant, the components are not, i.e. time, ...and and so time dilation should be dependent on the relative observer frames of reference. Are the authors saying this is wrong or am I not getting what they are saying?

Probability 'seems' like a relative concept so the error maybe expecting universal application from it (regarding infinite events).
Skeptic_Heretic
1 / 5 (1) Oct 01, 2010
@ Skeptic Heretic

Read up on Georg Cantor's Set Theory.

Read up on the physical rammifications of infinity. ie: Hilbert's Hotel.
You are right, but going a little bit OT we can prove that the set of real numbers has a higher cardinality, aleph-one or higher, than the set of natural numbers has, aleph-null.
You are right, but going a little bit OT we can prove that the set of real numbers has a higher cardinality, aleph-one or higher, than the set of natural numbers has, aleph-null. But without a conclusion there is no measure of cardinality.

You have two cars moving at different speeds for an infinite amount of time, which travels a greater distance? You can measure for a point in time, or for a given equal instance of like quantity, but at that point you create an upper boundary, thus reducing infinity to non-infinity. That is the only measure of how you can create cardinality, by instituting a boundary condition.
Skeptic_Heretic
3 / 5 (2) Oct 01, 2010
Blah, post edit problems. I really dislike the fixed time allotments and character limits.
Noumenon
4.4 / 5 (54) Oct 01, 2010
yea, they should just link to the physorg forum with a thread started for each article.
KevinPEdwards
5 / 5 (3) Oct 01, 2010
Hilbert's Grand Hotel doesn't disprove that thre are different sizes of infinity. The 'paradox' basically just shows that a countably infinite set added to another countably infinite set is a countably infinite set. The amount of real numbers is most definitely greater than the amount of integers. The lottery example shows their problemy with probability because if the number of loser is proportional to the number of winner then both are countably infinite.

However, that doesn't change what you're chances are to win the lottery in that one instance. Yes if you were to play the lottery indefinitely you would win an infinite number of times and lose an infinite number of times. You're conception would be that you lost a larger amount of times, but for every instance you lost someone could point to a unique instance you won.
getgoa
1.4 / 5 (9) Oct 01, 2010
the assumptions are presumptuous and fall into idolatry or the host of heaven.

For all practical purposes the only human thing here is the meteorological read of 50% and all else is basing more or less on the assumption that inifinity is finite and that could be very well a philosophical argument.

Its philosophy because man invented time on earth it is not infinite nor expansive but as the assumption was applied finite.

This develops into distances and man does not know time without distance, for all practical purposes in this argument you could get away with saying the world is flat and all man got off the ark the day before yesterday? its very wicked in the bible but the time is shown with disrespect for light and distance.

And so this shows how the bible can return a philosophical argument into a light argument just from knowing very basic phrases in the bible.
ShotmanMaslo
2.5 / 5 (11) Oct 01, 2010
The article is saying that with an infinite amount of events, one of those events is bound to end time. As time passes, the probability of that happening increases.


Not if the probability of such event is zero. Then it wont happen, even in infinite time.
Skeptic_Heretic
1 / 5 (2) Oct 01, 2010
Hilbert's Grand Hotel doesn't disprove that thre are different sizes of infinity.
Then give us a delineation or a methodology to measure infinity.
ShotmanMaslo
2 / 5 (8) Oct 01, 2010
Well it doesn't until you couple it with observation. With infinite time you must be able to violate causality and the various stability that classical mechanics brings through the accuracy of quantum description.

Basically, if time is infinite, we should see reverses in entropy as they aren't restricted, simply unlikely.

That's the problem, we're not seeing enough weird stuff.


No, if the probability to violate causality is zero. You may eventually get some macroscopic manifestation of quantum effects (like walking through a wall..) because probability of such thing is not zero (altrough extremely small), but what does it have in common with ending time? There is no quantum process that can end time..

Why should we see reverses in entropy and weird stuff? Given infinite time, they will eventually happen (maybe even happened?), but they will be so rare that probability of us observing them is virtually zero. I dont see how lack of "weird stuff" implies finite time.
KevinPEdwards
5 / 5 (2) Oct 01, 2010
So having skimmed most of the article, and read the first 10 or so pages. It seems that the end of time probaboloty is more of a result of the type of cut off. This jumps out at me particularly from their first figure (which I want to ask - is this a normal type of figure. I'm not in this field and to me it's just unclear. So I might be reading it wrong.) that the probability of time ending looks grater in their global cut-off scenerio. To me it feels like an artifact of approximating infinite time with finite time. If someone could point to a condtradictory point made in the article that deals with this, I'd appreciate it.
Pkunk_
2.7 / 5 (7) Oct 01, 2010
All this is fine , but i can't figure out where the hell they pulled out the 5 billion yr figure. It sounds like something right out of someone's a** .
KevinPEdwards
not rated yet Oct 01, 2010
Hilbert's Grand Hotel doesn't disprove that thre are different sizes of infinity.
Then give us a delineation or a methodology to measure infinity.


I believe it's if you can find an injective map from your set to the set of natural numbers or not.
joefarah
1 / 5 (8) Oct 01, 2010
"Heaven and earth will pass away, but my words will never pass away" - Jesus

Given his track record, I'll bet the end (of time) is a lot sooner than even a hundred thousand years before I subject myself to this lunacy. Come on now... for lack of a better measure, the universe would be as likely to last another 13 billion years than as not. I'm tired of simulations that are not well grounded.
Gawad
5 / 5 (3) Oct 01, 2010
Hilbert's Grand Hotel doesn't disprove that thre are different sizes of infinity.
Then give us a delineation or a methodology to measure infinity.


Eh. Well the hyperreals are designed for that (*R). Although I have no idea if they would help in this case they do let you work with and comapare infinites.

Anyway, I have the destinct feeling those reactions "Bousso and his coauthors' paper will likely be spurring...in the near future" are going to be mostly giggles from the back of the room. Please, this is a rediculous paper. "Brousso! The math doesn't work!" "O.k., what if, say, time were to end in 5GY?" "Oh yeah, o.k. now the math works"...long silence..."OH MY GOD THE WORLD IS GOING TO END IN 5GY!!!" ...stares..."You're not serious!?!" Releaved exhale. "Well, no, not really..."
Gawad
5 / 5 (4) Oct 01, 2010
All this is fine , but i can't figure out where the hell they pulled out the 5 billion yr figure. It sounds like something right out of someone's a** .
Basically, it is. Same one they got the Planck time cut off. It's just a math test.
baudrunner
2.8 / 5 (9) Oct 01, 2010
In their paper, they explain that in an eternal universe, even the most unlikely events will eventually occur - and not only occur, but occur an infinite number of times.
There is an inherent flaw in this reasoning. The theory is only viable in a potential universe that hasn't yet been created, but once the big bang creation front starts rolling, constraints are introduced because the evolution of the universe is a very finite progression following a single direction, random or otherwise. I believe otherwise, because the only things that are possible are the things that already are. The longer things last the more determined the progression is.

In this universe, existence is a finite band in the three-dimensional spectrum of an expanding entity. What is being created at the periphery is new, we are old, and what has been is no more, but the creation front will continue to expand beyond into incomprehensible depths, beginning the process toward an eventual demise.
otto1932
1.2 / 5 (17) Oct 01, 2010
"Heaven and earth will pass away, but my words will never pass away" - Jesus

Given his track record, I'll bet the end (of time) is a lot sooner than even a hundred thousand years before I subject myself to this lunacy. Come on now... for lack of a better measure, the universe would be as likely to last another 13 billion years than as not. I'm tired of simulations that are not well grounded.
But your godman is in reality already dead. Nietzsche and hawking killed and dismembered him.
DoubleD
5 / 5 (2) Oct 01, 2010
Why would the probability of an "ends time" event be any greater than the probability of a "no event ends time?"

In an infinte universe, it seems that both events (time ending vs. time not ending) are equally probable.

Am I missing something here ?
Gawad
3.7 / 5 (3) Oct 01, 2010
The following might interest some of you. I wouldn't normally refer decent folks to Motls' place, but he does have...an interesting take on this. Pretty well sums up *my* feelings that, well, Nature simply doesn't *care* that Bousso and company can't do math:

http://motls.blog...tml#more

Anyway, it a hilarious read to boot.
A_Paradox
5 / 5 (1) Oct 01, 2010
Two thoughts:
1/ it wont be a "bang" but a whimper with no echo

2/ seems like it will favour borrowers more than lenders
Quantum_Conundrum
1 / 5 (6) Oct 01, 2010
But your godman is in reality already dead. Nietzsche and hawking killed and dismembered him.

"My sheep hear my voice, and a stranger they will not follow..."
A_Paradox
1 / 5 (2) Oct 01, 2010
Two thoughts:
1/ it wont be a "bang" but a whimper with no echo

2/ seems like it will favour borrowers more than lenders
AAhhzz01
5 / 5 (3) Oct 01, 2010
*grins*

Of course...

Time could have ended since I started reading this article. Paused for an indefinite, but non infinite period, reversed direction, wound all the way back to the big bang, rebounded from that event and wound forward again to let me finish this post.

I, with a conciousness only attuned to a forward motion in time, would never notice the changes would I?

no1nose
1 / 5 (3) Oct 01, 2010
pi has been shown to equal 3.0 at plank length. I think we would see an expansion of the plank length and time just prior to the end.
Mr_Man
not rated yet Oct 01, 2010
It seems logically that even if "time does stop" in the universe, the universe would still have expanded infinitely. If all that encompasses everything ceases to expand, the word infinite itself ceases to have any meaning. It still expanded "infinitely".

Thus, the universe expands and time goes on infinitely until "infinite" ceases to have any meaning.

If the universe "stops expanding" or if "time stops", that is it - there is no way for an outside observer to exist, no way to measure it.

This also means that anything we consider to be infinite also is not possible for it to really be infinite.

I always thought of time ending as heat death of the universe - all matter decaying into the lowest level of energy until the universe consists only of that, all particles cooling until the universe has all mater symmetrically smeared through out, perhaps at this point there is no energy left to excel expansion?
droid001
1 / 5 (3) Oct 01, 2010
As I understand, time is a vibration. Do creation of time needs energy? Where that energy comes from?
Husky
1 / 5 (2) Oct 01, 2010
I think Schwinger particle/antiparticle creation is the driving force behind darkenergy, true, the particles will annihilate shortly after creation, but due to CP violation, different spacetime curvature between particle/antiparticle, the net result of the annihilation is i think not zero but actually slightly negative, causing the unfolding of curved spacetime around it, this in turn creates more, butt less curved spacetime volume in wich new Schwinger pairs can spring briefly into existence, hence an accellerating process. My prediction is that as the voids between the galaxies grow so thin, without constraints by matter/gravity/magnetic forces that would put drag on this Schwinger pair production, at a certain point the the production becomes faster/more energetic than space can uncurl, hence numerous big bangs in the universe at the size of these voids, explains hyperinflation as well, it was already inflated
Husky
1 / 5 (2) Oct 01, 2010
so in a sense, i think time linked to the voids are ended, as the voids make way for new universes were timers start again
MathieuHamaekers
5 / 5 (4) Oct 01, 2010
I think the authors of this theory make a big mistake. Since Einsteins special and general relativity saw the daylight in science, everybody in physics should know that space time and energy are intrinsicly interrelated, and can't exist as independend parameters. So if time would end, space and matter would stop existing either. I think they confuse the property's of mathematics, where infinit numbers can be used, with the property's of the physical world. The reality is not a mathematical equasion. You can use mathematics to modelate physical property's but if you project the nature of mathematics on the physical reality, you get mixed up in surrealistic statements like this article. By the way. The lotery has statistically always a winner because the lottery is designed with the helpe of the law of the smal and great numbers, to be sure that evey week, somebody wins. Otherwise, people will stop bying lotterytickets. There are exeptions but than next week there will be two winners.
mrlewish
3.7 / 5 (3) Oct 01, 2010
Their false assumption is that there is actually something like infinity in the real universe, it is a mathematical construct used to describe very very large things but in reality it does not exist. It is in other words a Reification. look it up.
RobertKarlStonjek
2.5 / 5 (4) Oct 01, 2010
In an infinite Universe where one unlikely event occurs once, the probability of it occurring during any particular interval is 1/infinity and the probability of it occurring in any particular region of space is also 1/infinity. The above article only considers the total number of events (infinite) and does not consider the other two dimensions which are both 1/infinity for any given event.

In other words the infinities cancel out. If we include an observer then the infinite universe starts to make sense ~ the maximum observable interval and spatial extension are finite for any one observation (snapshot). If we ask about possible events in the Milky Way then we first observe that total interval for the existence of the Milky Way is finite, as is the existence of any body or particle. With these finite parameters one can then model probabilities on a per-frequency-per-interval-per-space-time region and the infinities are overcome. It makes far more sense than the Big Bang Model...
RobertKarlStonjek
1 / 5 (2) Oct 01, 2010
In an infinite Universe where one unlikely event occurs once, the probability of it occurring during any particular interval is 1/infinity and the probability of it occurring in any particular region of space is also 1/infinity. The above article only considers the total number of events (infinite) and does not consider the other two dimensions which are both 1/infinity for any given event.

In other words the infinities cancel out. If we include an observer then the infinite universe starts to make sense ~ the maximum observable interval and spatial extension are finite for any one observation (snapshot). If we ask about possible events in the Milky Way then we first observe that total interval for the existence of the Milky Way is finite, as is the existence of any body or particle. With these finite parameters one can then model probabilities on a per-frequency-per-interval-per-space-time region and the infinities are overcome. It makes far more sense than the BB Model
daywalk3r
3.6 / 5 (20) Oct 01, 2010
There is no "probability", as there is only ONE possibile real solution.

So trying to "calculate" the probability of "time ending" for various future "points in time", while in fact understanding so little about the subject (and feel free to quote me on that), is about as perfect of an exercise in futility as it ever gets.. Almost as good as guessing the result of 1+1, while knowing numbers, but "not being so sure" how to add or substract them..

---

To me, it seems like the authors could use some lectures in basic logic, and then they might realise, that:

Probabilities do NOT define reality, but it is REALITY which defines the probabilities!

And if some people think, that "there is a probability of it being the other way around", it is hardly surprising that they actually believe (and claim to be able to explain):
that in an eternal universe, even the most unlikely events will eventually occur -- and not only occur, but occur an infinite number of times.
daywalk3r
3.7 / 5 (21) Oct 01, 2010
(continued)

Action/re-action, cause/effect, every event has a specific reason as to "why" it is actually happening..

There is no such thing as "everything will eventually occur within an infinite time frame". As long as it does not meet the very basic rules of consistence (and so existence) within its local environment (the local universe), it's just NOT going to happen. Period.

So far, most of the events which were ever observed or studied by mankind, had (sooner-or-later) allways a cause/reason attributed to it.

And the evidence is so crushing, that we have very little reason to believe, that there would be no cause/reason behind events currently not so well (or not fully) understood - ergo phenomena (I hate that word, it's being abused too much.. :)

So running around and spouting pearls like "everything will happen within an infinity, no matter how ridiculous it is.." and then even pulling conclusions from that, is ridiculous, to say the least..
daywalk3r
3.4 / 5 (18) Oct 01, 2010
While the space-time Interval is invariant, the components are not, i.e. time, ...and and so time dilation should be dependent on the relative observer frames of reference. Are the authors saying this is wrong or am I not getting what they are saying?
Exactly.

Even time itself has to be treated "relatively", and therefor it does not matter at all wether it stretches or contracts ad infinitum. It will never reach the point of "infinitely small" or "infinitely large" within a refference frame of the "in situ" observer - ergo, IT WILL NEVER STOP.

Time could be considered nearing a stand-still (or the opposite), but only if you compare 2 different "points of view" - like, for example, when an external observer observes the time "slowing down" for another observer, which is closing in towards a black hole. The relative "time-flow" delta between them will at some point be so large, it could practically be considered as "infinite", though in reality, this point will never be reached..
Pyle
5 / 5 (1) Oct 01, 2010
Great, so time has ended an infinite number of times and not ended an infinite number of times since whenever. Helpful. It's a wonder that people don't start shooting astrophysicist philosophers.

I wonder if we knew the exact improbability of being somewhere else that we couldn't actually be there?

If he had one left, DA would be laughing his ass off about now.
daywalk3r
3.6 / 5 (20) Oct 01, 2010
Are the authors saying this is wrong or am I not getting what they are saying?
In short, the authors are using whacky philosophical reasoning to pull conclusions out of very limited scientifical knowledge.

And yes, seeing as probability is used to model reality, which actually gives some pointers as to from what "village" (or should I say "camp"?)
they are comming from, it's safe to assume, that there is quite a big "missing link" between what they believe in (QM/CI), and what you base your arguments on (GR/SR).

Although they are not directly saying, that what you wrote is wrong, there is reason to believe that they probably don't believe that what you wrote, is true :)
chandram
1 / 5 (1) Oct 02, 2010
Time does not seem to have a beginning and so will not have an ending. Time is basically a relative concept and can have different beginnings from different points of view. In fact if i may say that time is really what the universe and its contents have been produced out of. Whatever energy we have in this universe is dependent on the uncertainty associated with the birth of the universe. It was not born in no time! The smaller the time is for birth, the higher will be the energy content with which it got born. Similarly, the mass content of the universe comes from space fluctuations that took place at birth. Thus the concepts of both space and time are in direct relationship with the mass and energy contents of any universe.
trekgeek1
4 / 5 (2) Oct 02, 2010
"Heaven and earth will pass away, but my words will never pass away" - Jesus

Given his track record, I'll bet the end (of time) is a lot sooner than even a hundred thousand years before I subject myself to this lunacy. Come on now... for lack of a better measure, the universe would be as likely to last another 13 billion years than as not. I'm tired of simulations that are not well grounded.


So you are talking about Jesus' track record and his coming back and you are refusing to lend yourself to the "lunacy" of this article? You are sick of simulations that are not well grounded but you are a Christian? You've based your entire belief system on accepting without evidence or simulation. Get your head out of your........... well, you know.
Benbenben
5 / 5 (1) Oct 02, 2010

I flip coins: 50/50 head/tail
In fact, there are an infinite number of me(s) flipping coins,
1 per second,
from this time, forward
without cease.
The chance is large that, as 'me-all' continue to flip,
each of me will, on an individual basis, eventually have a flip result of 'head'.
There IS also an extremely small chance
that at least one of me
will never flip and get 'head'
(but instead will always get 'tail'...so don't feel too bad for this possible-me).
The chance of a me continuing to only get 'tail' and never any 'head' far all time, is so small
it might (correctly) be called infinitesimal but is still nonzero.
>>>Every possibility of infinitesimal probability,
must have at least an infinitesimal probability of never occurring.
nuge
not rated yet Oct 02, 2010
Perhaps an oversimplification, but: If we can easily accept that the space-like dimensions come to an end at some point, why is it difficult to accept that the time-like one would also?
oliverrp
not rated yet Oct 02, 2010
Anybody seen an accepted definition of infinity lately?
TDK
1.3 / 5 (13) Oct 02, 2010
If observable universe appears like interior of black hole, then the time and space dimensions will exchange their places at the event horizon. This may be perceived like end of time dimension at the event horizon.
Benbenben
1 / 5 (2) Oct 02, 2010

I flip coins: 50/50 head/tail
In fact, there are an infinite number of me(s) flipping coins,
1 per second,
from this time, forward
without cease.
The chance is large that, as 'me-all' continue to flip,
each of me will, on an individual basis, eventually have a flip result of 'head'.
There IS also an extremely small chance
that at least one of me
will never flip and get 'head'
(but instead will always get 'tail'...so don't feel too bad for this possible-me).
The chance of a me continuing to only get 'tail' and never any 'head' far all time, is so small
it might (correctly) be called infinitesimal but is still nonzero.
>>>Every possibility of infinitesimal probability,
must have at least an infinitesimal probability of never occurring.
A_Paradox
1 / 5 (2) Oct 02, 2010
Two thoughts:
1/ it wont be a "bang" but a whimper with no echo

2/ seems like it will favour borrowers more than lenders
plasticpower
5 / 5 (2) Oct 02, 2010
I don't know what's better, the article or the comments.
I keep wondering, is the number of things that the human mind simply cannot comprehend and explain at this moment finite or infinite? Can we even comprehend infinity? Have humans ever observed true infinity in nature? Is it possible to say something for certain IS infinite with our current existing bank of knowledge?

As far as I can tell, the only things truly "infinite" are numbers, which is a concept us humans (who have not yet PROVED that anything is truly infinite), have come up with. Is the concept of infinity some kind of a glitch in our intelligence?

Are we forever bound to have incomplete theories to explain our world? We can't tie quantum mechanics with the standard model, our math allows for infinite sets and "imaginary" numbers that cancel each other out, we don't know if we can compute Pi to its last digit.. We don't have a complete picture of any part of this world. But we're good estimators.
Skeptic_Heretic
3.9 / 5 (7) Oct 02, 2010
The chance of a me continuing to only get 'tail' and never any 'head' far all time, is so small
it might (correctly) be called infinitesimal but is still nonzero.
It depends on who you marry, you may never get either, regardless of how many flips you perform. She may just take your coin and give you no tail or head.
genastropsychicallst
1 / 5 (6) Oct 02, 2010
... not within 5 billion years but per 5 moments ...
Noumenon
4.4 / 5 (55) Oct 02, 2010
... not within 5 billion years but per 5 moments ...


Hmm interesting, could you elaborate? [bot check]

(SH, thks for the laugh.)
otto1932
1.3 / 5 (16) Oct 02, 2010
But your godman is in reality already dead. Nietzsche and hawking killed and dismembered him.
"And she bare him a son, and he called his name Gershom: for he said, I have been a stranger in a strange land." ex2
"My sheep hear my voice, and a stranger they will not follow..."
"2Do not forget to entertain strangers, for by so doing some people have entertained angels without knowing it." Heb13
Husky
5 / 5 (1) Oct 02, 2010
if anything is possible, even that time will end, than its by definition possible that time will NOT end also, how does the author adress this contradiction?
Also the theory implies that anything can happen and given enough time/space, WILL happen, so its inescapable conclusion that there must be a planet out there made out of swiss cheese and spare tires?
Glen_Lincoln
not rated yet Oct 02, 2010
What is implied by time ending? It means that it's like a movie that the projecter stops running, and we all become a frozen still picture for all eternity.
Noumenon
4.4 / 5 (54) Oct 02, 2010
..to elaborate on my 1st post,...

...Any type of event that has nonzero probability [in an eternal universe] will happen infinitely many times, usually in widely separated regions that remain forever outside of causal contact. This undermines the basis for probabilistic predictions of local experiments...


Not necessarily, it may merely mean that an infinite universe is not intelligible.

Given the nature of mind, an understanding of some aspect of Reality implies subjecting it to intrinsic a-priori conditions, ...an a-priori conceptual framework necessarily involving the intuitions of Time and Causality. Reality is not intelligible apart from being conceptualized by mind (truism)....
Noumenon
4.4 / 5 (54) Oct 02, 2010
....At the opposite scale, qm still gives the "impression" that there exists some "underlying reality" yet unexplained. The reason is that, it is not intelligible locally within the conceptual framework of Time and Causality. This implies an intrinsic limitation of a-priori intellectual intuitions in rendering reality intelligible, and likewise at the infinite universe scale.
Noumenon
4.4 / 5 (53) Oct 02, 2010
if anything is possible, even that time will end, than its by definition possible that time will NOT end also, how does the author adress this contradiction?
Also the theory implies that anything can happen and given enough time/space, WILL happen, so its inescapable conclusion that there must be a planet out there made out of swiss cheese and spare tires?


I think they define 'event' as one that occurs within the realm of possibility given the known laws of physics.
Quantum_Conundrum
1 / 5 (3) Oct 02, 2010
So, if a guy flies around in a relativistic space ship accelerating at 10m/s^2 for really, really long time so he is moving like 0.9999999999999999999999999999c, then when he stops is the universe going to be gone?
MorituriMax
1 / 5 (2) Oct 02, 2010
Or... as ConfusedMatthew would say, "A Wizard DID IT!"
Truth
not rated yet Oct 02, 2010
So many women, so little time....I'm going out tonight!
dtxx
1 / 5 (3) Oct 02, 2010
So, if a guy flies around in a relativistic space ship accelerating at 10m/s^2 for really, really long time so he is moving like 0.9999999999999999999999999999c, then when he stops is the universe going to be gone?


Suppose you do go 99.999999...% of c and after a day's time for the astronaut 5GY years has passed on earth. Time would obstensibly "end" for those on earth, but the astronaut would have only experienced 1 day of time. How long it will be until "time ends" depends on your frame of reference. Not every piece of matter in the universe is moving at the same speed or through the same intensity gravity well as we are on earth.
Empyre
5 / 5 (2) Oct 02, 2010
If you enter an infinite number of lotteries, you will win an ininite number of times, but the odds of winning any particular one of those will still be as unlikely as the first one.
hush1
1 / 5 (3) Oct 03, 2010
The half-LIFE of RADIOactivity.
The LIFE and/or DEATH of the universe.

The math is fine. The worded languages are fine.
Both are fine with a set of (independent?)rules.

Is this cross talk? In the wider sense than defined?
Time(pun intended)will decide the fate of cross talk.


5thabove
1 / 5 (5) Oct 03, 2010
The needed inertial frame of reference to count from the beginning was provided by Mass (it wasn’t moving so you can’t ask where it came from, and it moved at that first point in time, not before or after, because this is exactly how long it took to make this many atoms and the letter X to keep counting atoms from using the weak force asymmetry value {a} that replaces the = sign in equations between the weak force and the strong force to correct Newton’s law since no one has yet noticed that Ohm’s and Einstein’s favorite equation not to mention the basic rocket thrust equation are off by exactly the same amount if you were to pick the same point in time to measure your course from. You need the Observer's mass in oscillation to have time.

John^^
5thabove
1 / 5 (5) Oct 03, 2010
And there is an end of time...it happens all the time with each tic of the clock, each Mass oscillation cycle of the weak force. Energy in the weak force and energy in the strong force remain in balance connected by the comma created by the asymmetry of the weak force which is the most important piece of physics as it “stirs” up the energy present in the EM-GAV field (Higgs) in the strong force otherwise all we’d see is the mass potential energy of iron spread out evenly like water finding its level.

John^^
Bob_B
not rated yet Oct 03, 2010
The Sun is expected to burn out in 5 billion years...which will happen 1st? All bets accepted!
Sirandar
5 / 5 (1) Oct 03, 2010
This seems like a stretch to me ...... most events are lost in chaos anyways so it doesn't really matter how many times they occur.

If the universe was going to end in 4 billion years because of an infinately improbable event it probably would have already. My bets are on a probable event that just hasn't happened yet.
jsa09
not rated yet Oct 03, 2010
I find it very strange that philosophical arguments about infinity end up with a number. This makes me think that the philosophers doing the math are worse at math than I am.

Doesn't matter to me what the number is 5 billion or 25 billion or 5,000 billion a number from infinity is just plain wrong.

What is a fun experiment is thinking of buying an infinite number of lottery tickets in an infinite number of lotteries. I find it difficult to enter a lottery twice a year and bemoan the loss of money those tickets cost.

Even when I know I will win the lottery one day (If I lived that long).
Quantum_Conundrum
1 / 5 (3) Oct 04, 2010
What is a fun experiment is thinking of buying an infinite number of lottery tickets in an infinite number of lotteries. I find it difficult to enter a lottery twice a year and bemoan the loss of money those tickets cost.

Even when I know I will win the lottery one day (If I lived that long).


The odds of winning the lottery are small enough, and the prizes small enough that you would have a net negative if you played the lottery infinite times, even if you won infinite times.
Kingsix
4.6 / 5 (5) Oct 04, 2010
This is my biggest problem with science today.
Lets make a theory and form assumptions to support that theory. Sometimes it makes about as much sense as mythology.

Here is my new theory of everything.
I am going to assume that something cannot exist in nothing, so.. The universe is on the back of a very large slug moving across another dimension. Currently the universe is expanding because the slug is stretching out as it moves, pretty soon, lets say 3 billion years from now, so I cannot be proven wrong, the next phase in the slugs movement will start and the universe will begin to contract.
Oh and how did it all start? The universe is a glob of the slime that the slug excretes to move easier, so there are many universes, and dark matter is what is holding us to the slug.
There you go, modify your beliefs accordingly.
brizzadizza
not rated yet Oct 04, 2010
@quantum conundrum

But if I played an infinite amount of lottery tickets and won an infinite amount of times, for every one of my losses I could find a unique win. Clearly that would mean that my bank roll would be vastly increased.

Or what about long strings of wins? With a sufficiently long series of games I am guaranteed to have a string of winnings, the sum of which is greater than the sum of all the losses before it.
derphysiker
5 / 5 (1) Oct 05, 2010
Another geocentric model for the universe? Because these guys cannot deal with infinity, the universe has to end?!

I'm sorry, but this is exactly the kind of article that gives science a bad name. The theory is highly speculative and has already falsified itself to a certain extent (or I wouldn't be writing this), yet it still is presented as if it has any impact on the world as we know it. It has not. It is pure theory and the authors should have balls enough to say "we don't know how to deal with this infinity mathematically so we have to let time end in our theory to get results".

Having said that I'd like to comment that due to the infinite thinning of matter and energy I don't see a problem with infinite time. Long before infinite time becomes a problem all physical activity will stop. No need to calculate further. No problem.
derphysiker
5 / 5 (1) Oct 05, 2010
(continued)
Oh, and if you really want to speculate about "Boltzmann babies" popping into existence, then also speculate about a nearly infinitely dense seed of matter and energy popping into existence with a bang. Maybe that's how this universe started in the first place...
derphysiker
5 / 5 (1) Oct 05, 2010
@quantum conundrum
Or what about long strings of wins? With a sufficiently long series of games I am guaranteed to have a string of winnings, the sum of which is greater than the sum of all the losses before it.

This is definitely the time when you want to stop playing... :-)

Yes, and this will happen an infinite number of times. But for the (energy) balance of the (universe) casino it is essential that you continue playing so it can reap its losses. Which leads to the conclusion that you will not be able to overcome your gaming addiction. Or else the universe has to end.

I hope this reasoning shows the problems that you fall into when dealing with infinities. Simply stated, every bet is off when you introduce something infinite into an argument. The church already lost with their claim of their god being of infinite power... and of infinite mercy.
toocool
4.5 / 5 (4) Oct 05, 2010
Seems the tail is wagging the dog here. Their math doesn't appear to work when confronted with these infinities, so they decide to end time as a quick fix. Why do we have math? To describe things. It is a language. We must remember that we base math and our use of it off of our observations of the universe. It is not the universe that bases itself off of our math.
georgert
5 / 5 (2) Oct 08, 2010
What I don't understand is the notion that given infinite time, any event with a probability >0 will occur an infinite number of times. If the universe expands indefinitely, the spreading of matter and energy over increasing space would also reduce the availability of matter or energy necessary for the causation of any event. In other words, an expanding universe with increasing entropy means the probability of any event no matter how common today approaches zero in deep time.
Damon_Hastings
5 / 5 (2) Oct 08, 2010
If infinitely many observers throughout the universe win the lottery, on what grounds can one still claim that winning the lottery is unlikely? To be sure, there are also infinitely many observers who do not win, but in what sense are there more of them?

This sounds like sophistry to me, or at least bad math. Just because two sets are both infinite doesn't mean they're incomparable. For example, if you pick a uniformly random number between 1 and 10 (including fractions), are you more likely to choose a number between 1 and 2 or a number between 2 and 10? Just because there are an infinite number of fractions in both ranges doesn't mean you can't answer the question. (The answer is that you're more likely to choose a number between 2 and 10.) Mathematicians compare infinite sets all the time. It's not that spooky. (Well, not until you progress beyond aleph naught, anyway.)
KomMaelstrom
5 / 5 (3) Oct 08, 2010
I'm sorry, but infinite time does not allow for unlikely events to magically happen. Just because the physical structure for a probability or improbability exists, does not necessarily mean that it will happen. Physics is predetermined by it's own system, so simply because one can understand the apparition of probability (which is merely perspective on data) does not mean that probability is an existence within Physics. Probability is a product of the human mind.
If I were to where blue tint glasses, white paper will appear blue, but the paper is not blue. Merely that the medium by which I am viewing the paper attributes a blue quality to all light that it allows through. In other words, by understanding a perspective, all information perceived through such is structured by the functions of the perspective.
TheobromaCacao
not rated yet Oct 09, 2010
"Positing infinity, the rest is easy" -- R. Zelazny

derphysiker gets it. Given infinite time, any non-zero probability event, such as (say) the big bang, will occur infinite times. I'll be typing this an infinite number of times. In fact, I'll be Master of the Universe an infinite number of times. Just apparently not this time. Oh well.

Infinity is fun! Collect the whole set!
Deuterium2H
5 / 5 (3) Oct 09, 2010
Seems there is a lot of confusion here with the Infinite. As some here have already suggested, many of you really need to study Cantor and transfinite Set Theory, before making pronouncements on topics involving the infinite. It would appear that even the authors of the subject paper have a very common error.

It is NOT necessarily true (or to be more exact, sufficient) that given an infinite amount of time... "Any type of event that has nonzero probability will happen infinitely many times". The Set of Even numbers has the same size (cardinality) as the Set of Intergers (or Rational Numbers). However, every member of the Set of Integers is NOT in the Set of Even numbers, even though they both constitute a denumerably infinite set, and have an exact one to one correspondence.

Discrete events in Space-Time may also be "countably" infinite and have a cardinality equal to Aleph Nought. In which case they may be infinite, but not necessarily exhaustive, just like the Even numbers
stealthc
1.2 / 5 (5) Oct 09, 2010
infinite time does not equal all non zero events happening. Our universe does not have infinite time in the various phases of it's life. The big bang didn't last infinitely, it was brief. Did all events associated with that event happen? How about when things were cooling how about then? This argument ignores the fact that these probabilities might start off non-zero, didn't happen, and as the universe evolved turned non-zero (or perhaps even vice-versa). What a moronic assuming statistician styled suggestion.
Skeptic_Heretic
1 / 5 (2) Oct 09, 2010
infinite time does not equal all non zero events happening.
Well actually it does.
Our universe does not have infinite time in the various phases of it's life.
That's unknown, unless you can prove it.
The big bang didn't last infinitely, it was brief.
The "big bang" is happening right now and will last as long as the universe does, which very well could be infinite.
Noumenon
4.5 / 5 (52) Oct 10, 2010
.
jsa09
not rated yet Oct 17, 2010
Given infinite time then non zero probability events will happen. Our main problem is that some events that we attribute to having a non-zero probability DO in fact have a zero probability.

It may be non-zero probability that I will get up out of my chair and walk out to front lawn without opening the door in between. It may have already happened. I would put it down to being absent minded.

Does that mean I should introduce a spontaneous "end of all time" just to make it easier for me to do calculations that I don't understand? I don't think so.

Can use the unlimited funds and unlimited time rule and always walk away with a profit from playing roulette. Just bet on red or black and keep increasing your bet until you win.

Trouble with real world is that I don't have infinite funds.
abhishekbt
not rated yet Oct 19, 2010
A simple question -> The article describes two 'realistic' scenarios with 3.3 and 3.7 billion years as the limit.

How come the author of the article reached 5 billion years in the title of this article? That's too much of rounding I'd say!
derphysiker
5 / 5 (1) Oct 19, 2010
Why can't expansion asymptotically approach infinity, allowing a permanent margin where highly unlikely events still have a chance of not happening?

I think this will happen in reality. Due to the thinning out of matter and energy during the final fade many now merely improbable events will become impossible, leaving only the improbable high-energy events... like a new big bang.

reading this my own text over again strikes me with the feeling that this cosmology is simple enough to be the real truth... quick, lets start a religion! :-)

More news stories

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...