Bet 7
The universe will eventually stop expanding.
Bet 7
Duration ? years (02002-?)
Predictor
Danny Hillis
Challenger
Nathan Myhrvold
Stakes $2,000
will go to The Long Now Foundation if Hillis wins,
or The Institute for Advanced Study if Myhrvold wins.
Add your voice to a conversation with the bettors:
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Cosmology is subject to fads. If at any other point in time I'd bet that the current scientific consensus was wrong, I would have been right. Certainly there's a lot of room for surprises. We already know that there are all kinds of dark matter, and there may be all kinds of dark energy out there too -- maybe including one that's pushing in the other direction. What I'm really betting on is that the universe will turn out to be complicated in directions we haven't even figured out yet.
For instance, I don't believe that the measurements that show the universal expansion is accelerating are necessarily true. There's a long chain of evidence leading up to that conclusion, and I suspect there are mistakes in that chain. We have to do an awful lot of extrapolating when we measure things like the redshifts of supernovae at the edge of the universe, and I don't think we have things as neatly figured out as some people seem to project. Maybe light actually loses energy as it propagates over long distances. I'm not saying this is true, but something like that would throw off redshift measurements entirely.
Even if the expansion is accelerating as the evidence currently suggests, it may not continue to do so. We do not have any good theory of why it should be accelerating at all, much less why it should do so in the future. To me, this unexplained acceleration is an indication that we do not have it all figured out yet. I am expecting surprises. Not only is the world more interesting than we expect, it's more interesting than we can expect.
I think the evidence is pretty consistent [that we're going to end up in a cold, dark universe]. The reason to believe in a closed universe is either because you want to be contrary, or because you subscribe to an aesthetic notion of cosmology. I mean, it's kind of cool to think of the whole thing expanding and contracting: throbbing there for all time. [But appealing or not, most estimates about the pressure and critical mass of the universe right now make me win.] First, empirically, we have the fact that the universe is expanding right now. Also, in the past twenty years, astronomers have developed very clever, indirect ways of finding dark matter and they've discovered that there isn't nearly enough [to collapse the universe] -- not by a factor of ten. Finally, there are theories in cosmology that embrace the idea that the universe is a random accident, like a bubble in a bottle of fizzy water. In that scenario, bubbles like our universe form, and they expand, and they go away. [Take the evidence together and ] That's why I think I've got the upper hand here.
The universe will eventually stop expanding.
I appreciate that all other bets are very much specific about their timing and other conditions. But this one has an open time, which makes it unreal and diminishes the value of the whole Foundation's idea.
How are you (well, not you, but anybody in the future) going to check the result and decide on who is the winner?
I may exhibit my lack of humor here, but still will be glad to hear somebody's opinion.
BTW, generally speaking, I am here on N.Myhrvold's side
Good question to raise. Perhaps we can get Danny or Nathan on to explain their perspective. Offline, both have said they would not be surprised if this bet got resolved in the next few years. What they are waiting for is "general agreement" among astrophysicists about the value of Omega---mass of the universe. If greater than one, Danny wins; if less than one, Nathan wins. (I think I got that right.)
Lately there is indeed a drift toward Nathan's view in the data and explanatory theory, but some of the data is so bizarre (acceleration, etc.) that Danny holds there are clearly more surprises coming.
It may be that the debate continues for centuries. Both bettors are comfortable with that. Meanwhile a fundamental fact awaits: the universe either will or will not keep expanding, and that fate is already determined and is presumably detectable.
Does that clarify?
The following post was written by Gordy Kane and is posted here with his permission:
You may want to know that from the point of view of the data they discuss the Hillis-Myhrvold bet is over, since there are three independent sets of data that all agree and that all imply the accelerated expansion of the universe. But the wording of the bet means the data itself does not settle the bet, since the current cause of the accelerated expansion could disappear with time (over say some billions of years) and so finally the universe could stop expanding in spite of the current situation. It is actually possible to take additional data that is relevant to that, but not for well over a decade. Periods of such accelerated expansion are theoretically reasonable.
Gordy Kane
Since the universe is accelerating as it expands and that no theory adequately explains this acceleration, the entire assumption that we know enough about the universe to accurately estimate Omega is invalid. The odds are still 50/50 on if the expansion will continue. I would not resolve this bet until there are not any outstanding celestial phenomena that have no explanation.
Science bets need to be open ended, because science is open ended. Nathan and I independently concluded that we were not interested in making a date-specific bet on this.
As I see it, science is a process for arriving at an understanding of what is actually true. Once something has been established by evidence there has always been general consensus among scientists that it is indeed true. Sometimes, before the process is completed, there is a period of time when scientist disagree, but such a state of affairs is exceptional, and it rarely lasts for long. Almost all science is not controversial, and those bits that are don't stay that way.
This bet could easily be settled before many of the others. As Nathan likes to point out, one of us has already won, we just don't know who it is.
Neither Nathan or I care much what ”most scientist scientist think” right now. We care what is true. We both believe that is likely that the process of science will be able to establish this particular truth unambiguously one way or the other, and that it has not done so so far. We are willing to wait until it does. Forcing the issue to be decided at some particular point in time would be contrary to the spirit of Long Bets and contrary to the process of science.
One subtle correction to Stewart Brands statement: Nathan and I have agreed that I also win if Omega is exactly equal to one, in which case the universe stops expanding in the limit. Besides, as James Farley points out, the very idea of Omega may be wrong.
a consensus that the universe is expanding _now_, or even if the expansion of the universe is accelerating now, because there is no agreed theory that supports the currently observed expansion of the universe.
Would the bet be settled if there is an agreement on the past, and current pattern of the universe's expansion - projectable to the future - even if there was still no theory to explain that pattern?
There is no question that the universe is expanding now - that issue has been settled to the degree that it more than meets the test Danny and I have set. We also understand more or less why it is expanding - general relativity has overwhelming experimental support as the long range theory of space and time, and in GR it is hard to make a universe that sits still. So, you must expect a dynamic universe, and that squares nicely with the empirical evidence of expansion.
The question is what happens long term.
There is an expression among cosmologists (and others) "well, it's not the end of the universe... but you can see it from there".
That is what we want - to have a vantage point from which we can see the end of the universe. Such a vantage point is built on both experimental / observational data, and a theoretical context with which to understand the data.
As one posting pointed out, empirical data at the moment supports my view, but there is much that is not understood. There is data that the total mass of the universe is not sufficient to cause it to slow down and then fall back (or stay at steady state). There is also data that the expansion is accelerating - which again would tend to support my side.
But, people continue to offer up theories which support Danny's view. Most recently there is this paper
A Cyclic Model of the Universe
Paul J. Steinhardt, and Neil Turok
Science April 25, 2002
Both Paul and Neil are leading cosmologists, and whether their theory or another is correct, it is hard to close the book on this bet while new ideas like this keep popping up.
(As you can tell, Danny and I are not exactly at each other's throats over this - here I am supporting his point of view!)
The chance that a new theory or some discordant data might overthrow the dominant paradigm may seem small, but at the end of the 19th century a predominant number of physicists thought that the classical paradigm of Newton and Maxwell would soon create a complete description of the Universe. Yes, there were a few discordant data points, but surely those would be resolved soon enough.
But in fact, relativity and quantum mechanics both dealt significant blows to this point of view. It turns out that the world is not much like the 19th century view at all, although it is a good appproximation within a certain limited domain. Yet many phenomenon that are part of everday life (like light!) cannot be explained within classical physics.
An important element in settling the bet may be a better understanding of cosmology itself - and with it a better understanding of fundamental physics of space and time.
At the moment it is very difficult to get a theoretical model of the early universe that matches the microwave background data from the COBE satellite (and more data is on its way).
In addition, it has proven imposssible to date to construct a quantum theory of gravity - this may turn out to be as big an exception as the "ultraviolet catastrophe" was with the origin of quantum mechanics in the first place. In fact, there is a strong sense in which it is directly related to that.
It is possible that we could resolve this bet without having a good theory of cosmology or a good theory of quantum gravity. We have settled the expansion question this way and it is possible this could happen here say, with overwhelming observational data. But it sure would be easier to settle this bet with the vantage point that lets us see farther than we can today.
Nathan
First I think that this bet is more something for us to comtemplate, not so much an actual bet. Second I think that the fizzy water idea is closer to the truth, but I feel that other universes may exist. I aslo remember reading an article to support the idea of our universe having a fourth dimension, which would likely effect this bet quite a bit.
I personal have given this subject many hours of contemplation. The outcome of all the energies I have spent searching for answers is as follows: 1) We will never know the answer. It will take too long for the universe to change and therefor we will only have our "Hypothetical Points of View" to consider. 2) There are too many unknowns and we will never know enough of them to truly understand the truth. 3) Man, as we know him, will die out as a species long before the universe will ever give up the secrets of the actual origin or ending (which will only be the beginning of something new). 4) For every action there is a reaction. What goes up comes down, In has it's Out, Back has a Front, Top has a Bottom, Right has a Left, Beginning has an End, etc. - etc. - etc.. Nothing lasts forever, whatever lives, dies. All we have to do is look at the past and we see species of animals, plants, reptiles, insects even stars coming into existence and becoming extinct.
It is from these thoughts that I form my hypothesis that there will be an end to the universe as we know it. The question is "How". Will the universe continue to expand and eventually out grow its' ability to stay contained? Will it collapse? Will it be consumed by yet another universe? Perhaps a future species will discover a force so distructive that it will totally distroy the universe. One problem that prevents us from knowing what will happen is that we cannot see into the future. You can't see what hasn't happened. We can see in to the past though. All we have to do is read what is recorded or look up to the stars. At this point in time I tend to side with Danny Hillis. Would anyone care to bet on the "End of Time" or the "Origin of GOD"? They would be just as insane as the bet on the future of the "Universe". (June 1, 2001).
Here is a link to, unfortunately, just a small part of what is a very intriguing article from June's Discover Magazine.
http://www.discover.com/june_02/gthere.html?article=featuniverse.html
It is about John Wheeler's idea that "human consciousness shapes not only the present but the past as well." This could indicate a much more fundamental reason that we may never know the winner of this bet. Think of the duality of light, it can appear to behave as a wave or a particle it depends on how you look at it.
Another fundamental reason I think this bet is impossible to resolve has to do with human senses themselves. The universe bombards us with an infinite amount of stimulus all the time. We have a biological set up that senses and interprets only that very small amount of data that aids in our survival. We see and hear and smell only a very small part of what is really there, and then our brains further dilute the data down to useable chunks. It seems to me that there are whole sets of data that not only can't we detect, we can't even conceive of. Thus I don't think it is simply a matter of super computers collecting all the data we can think of (which would be impossible anyway since as far as I know none have infinite abilities), but there is in fact a much larger set of data that we cannot detect nor envision.
Please don’t get me wrong. I don’t mean to imply that these are questions we should not pursue. Quite the opposite really, for the quest that never ends is often the most rewarding and the thoughts and tangents that these questions lead to are often more fundamentally important to humanity than the question itself. I know I have spent many a sleepless night trying to wrap my brain around the universe, but let's not become too immodest and think we can ever do it, let alone in the next few years. Besides, what fun would that be? What would be left to think about? What would be left for humanity to pursue?
You've raised a number of good points that merit in-depth examination, so please pardon the length of my post.
> I personal have given this subject many hours of contemplation.
> 2) There are too many unknowns and we will never know enough of them to truly understand the truth.
I strongly concur with you here. My vocal cords groan reflexively every time terms like "Theory of Everything" or "The End of Scientific Investigation" are bandied about too casually. I don't even want to bear-wrestle the issues of Godelian incompleteness that this kind of debate often engenders but, fundamentally, I believe that nature is structured such that one cannot ever truly "know everything." And this is a gift IMHO; omniscience would be a terrible burden b/c there'd frankly be nowhere to go after that. It's only by having some kind of challenge that we can justify dragging ourselves out of bed in the morning-- that and some fresh mocha latte with whipped cream and chocolate sprinkles, but I digress… Moreover, as we ourselves create art and literature and ideas, we're adding to the stock of "unknowns" in addition to phenomena that are more traditionally regarded as natural. If I had to describe consciousness in 25 words or less (usually takes 2,500, bare minimum), it seems that its essence is partly in this inscrutability, with the capacity to generate mystery as well as to solve it. (Timothy Ferris, in his book "At Home in the Milky Way," discusses this toward the end of the book. A must-read BTW for that beach-book list along with John Grisham's latest lawyer-in-trouble potboiler.)
> 3) Man, as we know him, will die out as a species long
> before the universe will ever give up the secrets of the
> actual origin or ending (which will only be the beginning
> of something new).
"As we know" humanity. I've always wondered if one of those sci-fi scenarios is fulfilled and humanity were to evolve in an intentional Lamarckian fashion, say via directed germline alteration either organically or as a carbon-silicon hybrid of sorts, if one would still call the species "homo sapiens." Seems to me that the earlier species "dies off" and the new species takes its place. Which IMHO is a way of suggesting that the species definitions in an evolving niche are fluid. We could get goofy with some of those sci-fi brainstorms and envisage a settlement on a barren distant planet where people make themselves photosynthetic, or hook up an Acme external cerebrum temporarily to visualize 5 dimensions for all those tricky futuristic engineering problems. (Me personally, I think it'd be cool to be rewired to sleep upside-down like a bat—-fun with gene manipulation.) Even if they could manage to reassume good ol'-fashioned human form, would one still call these people "human"?
Back down to earth for the moment, I'm actually a lot more optimistic on this front. Undoubtedly we live in a hazardous epoch but over time I think that the safety nets of society will aggregate and improve out of pure necessity, with better and more accessible safeguards against biological hazards (like engineered viruses and bacteria) as well as an increasing suspicion of nuclear weapons, possibly after a hard experience of war with them. (An India and Pakistan-type regional impasse comes to mind.) Naturally as we learn to harness energy more effectively, as with fusion technologies and their successors, the corresponding danger increases of catastrophes provoked by either deliberate injurious use or from accidents. But as a general trend, my sense is that people will simultaneously develop ways to "localize" the effects of whatever is being undertaken and consistently construct multiple independent safeguards so that, even in worst-case scenarios, the damage is contained within a small region. The prototype of this thinking comes in the form of "deny-use" technologies that are designed with their own antidotes, e.g. a viral vector used in medicine that is instantly equipped with several disabling drugs against it should it be misused, plus short circulating half-lives, blocks against easy person-to-person communication, and the like. (Greg Blonder wrote an insightful article on this, "Eliminating the Tools of Terror," Technology Review, April 2002.)
In addition, I really do think that an embarcation into space is not far off, something that's crucial over the long term by providing a kind of insurance policy. IMHO our greatest danger is while we're still earthbound, with "all our eggs in one basket" as it were. Less from anything particularly exotic (big nasty asteroid) but from our own "growing pains"—environmental problems, famine, war, pestilence, the usual 4 horsemen stuff. Besides providing for an infinitude of Kodak moments (look Mom and Dad, over there, it's the Crab Nebula!), the new frontier would introduce a sort of "outlet valve" for populations to spread out and move when the tension of crowding and stasis build up, reducing the dangers of societies turning on each other in quarrels over scarce resources. This was Frederick Jackson Turner's frontier hypothesis a while ago, and in many of history's mass migrations (the Huns, Visigoths, Vikings, Ellis Island immigrants, half of Florida's population) this outlet came in handy.
> 4) For every action there is a reaction. What goes up
> comes down, In has it's Out, Back has a Front, Top has a
> Bottom, Right has a Left, Beginning has an End, etc. -
> etc. - etc.. Nothing lasts forever, whatever lives, dies.
Leptons and photons, for example, do last forever; they have no known decay process.
> All we have to do is look at the past and we see species
> of animals, plants, reptiles, insects even stars coming
> into existence and becoming extinct.
You've noted a general propensity of observed phenomena to be bounded in some manner, and this is definitely a common motif in nature. However, it's not uniformly the case. Just invoking some simple examples of topology, a soccerball is an "unbounded" object (unless Ronaldo has just belted all the air out of it into the goal). You can start at any point on the ball and follow its circumference, never ending in your journey. Same deal with that cinnamon-glazed donut on the way to work in the morning that makes our bellies big rounded objects too-- such a torus is "unbounded" and, if you were a mite having alighted on the donut surface for a nibble, you'd feel as if you were walking forever around its edge. Same thing with a Mobius strip or Klein bottle that give you headaches as you try to track their surfaces-- effectively "infinite" as far as the boundaries are concerned. And there are even more exotic topologies that defy simple presumptions. Black holes have an "in" but no "out," at least by most descriptions. Light is frequently polarized to have a "right" hand with no "left" hand. We have a slight excess of matter vs. antimatter which allows us to have structure at all. The Bohr-Sommerfeld atom, depending on the element, possesses an unpaired electron without a "balancer" in the same orbital, enabling chemistry to occur. And everything goes haywire at the quantum level; the reason that we observe photons of light traversing a particular path, according to Feynman's quantum electrodynamics, is that all of the paths sniffed out by the photons cancel out except for one, which is not "bounded" (canceled) by a partner. These unbounded states and asymmetries are just as ubiquitous as their neatly bounded symmetrical counterparts.
At the cosmic scale, remember that we have no idea at this point whether the universe is finite or infinite, and there are many cosmologies that aver the latter. Andrei Linde, one of the astrophysicists who further developed Alan Guth's inflationary cosmology, has proposed a series of "eternally expanding self-reproducing bubbles" of which that which we currently find visible is an infinitesimal fraction of the population; basically, each progeny universe would bud off fractal-like from its predecessor in a region of "false vacuum," and it's fully consistent with the field theories. Max Tegmark, an astrophysicist currently at U. Penn, took a clever hypothesis even further by relating unified field theories to ensemble theories of mathematics-- i.e., postulating that any universe which could be described mathematically (and there are many systems from which one could choose-- effectively an infinity of universes) also exists physically, yet only those with sufficient complexity to beget self-aware substructures (SAS's) will be observable by their own constituents. (Annals of Physics, vol. 270, pp. 1-51, 1998-- can be accessed online at http://www.hep.upenn.edu/~max/toe.ps) Tegmark himself quips that this is just one of the wacky papers he puts out once in a while (most of his work is in the field of optimized cosmic microwave background measurements to remove confounders, of which he's published quite a bit). But the point of the work of Tegmark, Linde, and many others is that it's feasible to construct logically consistent models of the universe or "multiverse" that are vastly richer than the garden-variety unitary expanding bubble to which we're accustomed. When it comes to the life within that universe, again we're operating from the limited experience of what we've so far observed on earth. Life, viewed crudely, arose as a means for assemblages of matter and energy to retain a particular pattern and structural integrity through time, hence the reproductive processes and all the mechanisms used in a cell's nucleus to maintain the DNA in its original sequence; life has evolved, in fits and starts, to become more effective at that. So in summary, when it comes to the universe and the inhabitants therein, it seems that we really know quite little about their nature and capabilities at this point.
> It is from these thoughts that I form my hypothesis that > there will be an end to the universe as we know it. The
> question is "How".
> another universe?
Well, not sure how hungry universes are but by definition two different universes are causally separated. Each one has its own "spacetime" and there's no space, so to speak, between them-- the "hyperspace" that you'll sometimes see in the diagrams of multiverses is a logical construct rather than anything physical. Another way of looking at it is that, by definition, different universes are non-interacting entities, and there's no common coordinate system for them since the phase space in which the vectors of direction are defined itself arises with the universe-- you don't have universes bumping up against each other. It's a tough concept to reckon with, but Alan Guth provides a good description in the next-to-last chapter of his book "The Inflationary Universe." Based on inflationary theory there may be universes budding out from this one all the time, at your desk, on your car, in your soda bottle. (This, incidentally, may well be the mechanism responsible for the observation that 10% of your laundry always seems to be missing when you take it out of your dryer...) The little universe just stretches out into a distinct "dimension" from the one that gave rise to it. Different universes simply have an entirely disparate set of coordinate axes or dimensions, which spring up with them, relative to each other. There are some multiverse hypotheses that postulate nifty little strategies to transport between them via wormholes or the like (all very hypothetical stuff since nobody's submitted any papers on those other universes yet) but, as a rule, such transfers entail minimal movement of matter and energy from Universe A to Universe B. Said universe-hopper wouldn't traverse any "space" moving from A to B; he/she would effectively just be "logically transferred" into a different coordinate system. (See Kip Thorne's "Black Holes and Time Warps," for example.) Thus in a putative multiverse the notion of a "population" of universes is merely a heuristic descriptor for what are separate, isolated realms fundamentally by their definition itself.
> ... we cannot see into the future. ... We can see in to the
> past though.
Once again I agree with the cautions that you voiced late in the statement, but this caution also entails any claim whatsoever regarding the universe's structure and its end or lack thereof. What we know is currently confined only to what has arrived at our telescopes on earth; there could be wildly different structures, even varying laws of physics, in presently unobservable regions outside the horizon of 15 billion light years or so. (As an example, the fine structure constant, a measure of the strength of charged-particle interactions with photons-- equal to the square of electron charge over the product of Planck's constant and the speed of light, one of the most fundamental constants of nature-- may actually be changing with time. See Webb et al., Phys Rev Lett, vol. 82, pp. 884-7, 1999.) So it doesn't make much sense to talk about the universe "ending" b/c while we've learned an extraordinary amount, we still possess a thoroughly incomplete picture even of the observable portion, nor does the very term "end" even have a meaning, necessarily, in this context. It would be superimposing an old cosmological worldview on a phenomenon that may well be far more complex than we'd first imagined. The Big Bang theory is well-established and inflationary ideas are also drawing support, yet science, as you've intimated, does not evince "final truths." Rather, it provides provisional knowledge and theoretical structures that are subject to revision in the face of future conflicting data and/or logical considerations, and there is probably a lot more to the universe than what we currently have in hand.
As a simple example, in the debate over the omega density itself, it was long assumed that the omega=1 condition (with a flat, Euclidean geometry) would correspond to an expansion that would eventually approach, asymptotically, a halt. This prevailed as dogma for many decades. But then in 1997-98 Saul Perlmutter and colleagues discerned evidence for an accelerating expansion which practically *nobody* had predicted, raising the possibility of an antigravity "cosmological constant" force. The geometry is flat, yet it's not slowing but accelerating its expansion, the antithesis of prior assumptions. In much of the 19th and 20th centuries the Second Law of Thermodynamics was assumed to result, necessarily, in a heat death with increasing entropy and thermal equilibrium. But in the past few decades it's been demonstrated that in an expanding universe, the actual entropy increase lags far behind the potential (maximum) increase, moving the universe further away from equilibrium with time rather than toward it. (See, for example, David Layzer's book "Cosmogenesis" for a concise discussion and some excellent figures which illustrate it.) The accelerating expansion is sometimes taken to mean that matter would tend to thin out and disperse over very long periods of time (or at least that superclusters of galaxies would spread irretrievably apart), yet the repulsive "cosmological constant" force, whatever its nature, may well be some field inherent to the vacuum itself that exerts a net gradient over long distances-- behaving, in many respects, like the "matter/energy" with which we're more familiar (in fact the antigravity is often dubbed "dark energy," in analogy to the "dark matter"). It's another exemplification of the fact that even empty space is anything but vacant-- one can't take any concept for granted as cut-and-dry. This is the essential problem with statements about the universe's long-term outcomes and future. The conclusions in scientific papers always tend to be limited in scope and quite cautious, which is a fidelity to Socrates' old counsel of being wise by recognizing our own ignorance; it's hazardous to presuppose too much about the structure of an early-Cenozoic era fern, let alone about something so vast and varied as the universe. The cosmological field is replete with magnificent accomplishments, and it's extraordinary that we can peer backward to the first quintillionths of a second after the Big Bang and glimpse something about the matter/radiation soup that was frothing then. There is a lot of uniformity in the universe's large-scale structure (again, that which we can observe, at least), but also a number of surprises. When one is talking cosmically there is such an abundance of phenomena we're only beginning to decipher, and so many assumptions and approximations that are often taken for granted (and which may be inaccurate, or just partial elements of phenomena that are far more subtle), that any sweeping statement on a topic like the universe's very long-term future will have more strings attached than a float in the Macy's Day Parade. These are nuts-and-bolts questions about the very nature of space and time itself, not to mention, as noted earlier, the possibilities in unobserved regions. Notice that we're not even bringing up here the wacky wild-card prospects, such as technologically-advanced beings changing physical constants or similar out-of-the-box alterations (it's been thought of before); just a natural description of the segment of the universe that's observable to us is unpredictable.
As Dr. Myhrvold noted above, in the late 19th century many of the most brilliant scientists of the era were predicting that physics had come to its end; then radioactivity, relativity, quantum physics, chaos theory, and a host of other wonders ensured that the grant money would keep on flowing. We're limited in what we can observe and even imagine, after all, by our senses and our fund of experiences up to this point; prior to the late 1800s nobody had even conceived of radio waves, nor considered that we would have blasts of them zooming through the air 24-hours a day. There are probably things that we've scarcely imagined about the universe's structure, and I wouldn't be surprised if the "bubble" to which the omega calculations have been applied is revealed to be a tiny piece of a much vaster structure. There are many who are actively contemplating this already. Check out this link: http://groups.google.com/groups?q=group:soc.retirement+"max+tegmark"&hl=en&lr=&ie=UTF-8&selm=3CA83ADB.6CFA0094%40fuzzysys.com&rnum=1
It's a Usenet post generously provided by a frequenter of the soc.retirement newsgroup, a report on a recent (April 2002) Princeton conference entitled "Science and Ultimate Reality" (author Tom Siegfried, Dallas Morning News, April 1, 2002). It's basically an intellectual playground recess day for astrophysicists (oh, to be a caterer serving canape hors d'oeuvres amidst that crowd), but it's a demonstration of the breadth of thought on this matter.
Sorry again to be so long-winded, but you provided an especially thought-provoking post that deserved close examination.
Wes
Brevity counts.
Yup
It seems to me that it would have been better if the bet were phrased in a way where it could at least in principle be resolved in a finite time, e.g. "There will be complete consensus in the scientific community that the Universe will stop expanding." Note that if omega=1 but there is a cosmological constant, it will expand and even accelerate forever. All current evidence points strongly in the NO direction.
Still, it is not clear how the consensus of the above formulation of the bet could ever be achieved, unless all agree the acceleration is due to an unchanging cosmological constant (w=-1). If it is some kind of quintessence, one can never know for sure, that some new field will not take over and reverse the expansion in the far future.
However, it may be possible someday to prove that "the Universe will continue to expand for at least 10^x years", where x is large. I would bet (in the not-putting-up-$1000 sense) on such a consensus arising at least for x=12.
If the universe is indeed expanding, then all objects within it are also expanding internally. In other words; celestial objects aren't simply racing away from a central point of origin, unaffected internally by these forces of the expansion. Universal expansion is either briven by a Explosive force or a diminishing cohesive force. Either way these forces must affect all matter equally. Thus a planet, for example is not only moving away from a central location it must also expand from within. The Earth's surface will expand away from it's core. On the atomic level electrons will move away from their nucleus, and so on... Only from outside our universe would we be able to percieve this for within it everything would seem to remain constant except distance. This would suggest that universal expansion would stop, not when objects have travelled so far from center that from there own vantage point that they would seem alone, in effect in there own universe, but expansion would stop when all matter has expanded into a cosmic molecular dust both infinitely wide and small. At that instant our universe would resemble a halo of matter surrounding a void. All of our wisedom since the beggining of human kind would suggest that, at that point, contraction would begin.Culminating at the point of origin. In other words "dea vja vu (big bang) all over again".
If the universe As We Know It is a big bubble in a much larger cosmology, it is possible that it will continue to expand faster and faster - perhaps until it runs into another bubble and merges with it. At which point it would no longer be expanding. Who wins the bet in that case?
Objects don't expand internally from an expansion of space. The forces in a stable object are by definition in equilibrium. So the tiny outward force from cosmic expansion on the scale of the Earth is just part of the balance which includes gravity pulling inward versus electrostatic repulsion. Even our local group of galaxies, which is gravitationally bound together, will not be pulled apart by cosmic expansion. It is only on larger scales where things are not gravitationally bound to one another that things will fly apart faster and faster from each other.
I think it's the "When light was heavy" one, unfortunately I left the magazine at home.
IIRC, the gist was that 'dark energy' could fall to zero, or even reverse its effect causing the universe to collapse - possibly as soon as 10 billion years from now.
However they hastened to add that it's all "still up for grabs".
Here's a link to a press release on the subject.
'Runaway universe' may collapse in 10 billion years, new
studies predict
Personally, I think this bet suffers a bit from "casual science", where experts feel free to make fairly absolutist statements about big things because they're speaking casually, and hence imprecisely.
Usually, among experts, this isn't a problem, and if you press them, they'll say, "Well, to be more precise, we can't *really* be sure of this, and there *may* be exceptions to that," and so on. The problem arises when they're speaking to the laity, which often misses this distinction.
I don't think it's reasonable to speak in absolutist terms about something like the indefinite fate of the universe. I don't think any living or historical scientist's remarks on what *will* or *won't* happen should be taken as set in stone. We're talking conjecture, here -- very educated, very reasoned, very careful conjecture, but conjecture even so.
For one thing, time is, of course, part of the space-time tensor, and it may not entirely be sensible to say "the universe will eventually stop expanding", because, if and when it does, the nature of time may change as the nature of space changes, rendering the concepts involved somewhat altered and very possibly incomprehensible. Even on paper.
For another, the universe is a sufficiently strange place, not bounded by our expectations, that I *don't* think it's a given that it will either continue to expand or not continue to expand. It may very well pick a third option -- or a fourth and fifth option besides -- that doesn't fit into that neat equation.
Lastly, I often suspect that in practical terms the universe, as we perceive it, can thoroughly be considered a Schroedinger phenomenon, one whose apparently objective nature depends upon observation. So if we make a prediction about what will happen but don't stick around to see if we're right, then that prediction may not be worth anything.
I think this bet is really not about the state or fate of the universe, but rather about what consensus of theory scientists are likely to reach. And I think the bet would be much improved by a little rewording to that effect.
Expansion of our universe could be stopped by life/consciousness. We can now only speculate, how sophisticated and mighty life/consciousness would be after 10 or 20 billion years from now and how it affects cosmos than. When we predict future, we often forget how rapid our technology is growing. If we maintain this tempo, we have to be sure to possess tools for manipulating planetary systems already in couple of millions of years.
In order for this prediction to come true the lastest scientific evidence that that seems to indicate that the expansion of the universe will continue forever will have to be proven wrong.
Maybe it will hit a wall.
What would happen to the money if both charities ceased to exist when (or if) the universe stops expanding?
In the category of 'for what it's worth' I'm now commenting on cosmology. ;-) I voted 'Agree' because My instinct says that the evidence for an expanding universe is being mis-interpreted. I think the universe is certainly changing, and the nature of that change is responsible for the current data, but the universe is not expanding. Hillis' argument to the effect that 'we are missing something important' has a 100% chance of being correct. What that thing is, and how it changes our perception remains to be seen.
I must admit that the evidence is stacking up in favor of Nathan's position. The consensus seems to be converging on a dark-energy dominated model that seems consistent with the supernova data, the microwave background structure, and the large-scale matter distribution.
Dark energy is still shard for me to swallow, but the evidence reported since we made the bet has supported Nathan’s position.
It seems discussion on this bet has stopped expanding. Any further chance to be able to read spectrum of views?
I think, all discussion about universe passes through a singularity and they also make a mention of God. Any one who agrees or disagrees with my view?
Ok I'm not a scientist or anything like that but heres my view on the subject. If you look at what scientist think they know about the "beginning," they think the big bang started as one tiny insanely dense particle. So dense it holds all of what we call the universe in something smaller than the particles of atoms. It becomes unstable and blows. This is very similar to a dying star. The fusion in the star stops, it swells, shrinks becoming very dense, eventually becomes a black hole sucking in all matter around it, then becomes unstable and explodes, and giving enough time becomes a star again. Is it that different from our universe ... just on a much much smaller scale. Every action has a opposite and equal reaction right? So if it started it has to end. If it ends it has to begin. At least in my mind it does.
the universe will never stop expanding because there isn't something that will prevent it from doing so and if there isn't anything that will stop the universe from expanding it won't.
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