Please create an account to participate in the Slashdot moderation system

 


Forgot your password?
Close
typodupeerror
×
Space Science

Big Bang or Cosmic Crunch? 94

Posted by timothy from the with-nougat-caramel-and-turkish-delight dept.
BrianGa writes: "Yahoo news is reporting on Princeton University physicist Paul Steinhardt suggesting that the universe never began and will never end, driven forever to expand in a series of monster explosions and contract every eon or so in a cosmic crunch. This is directly contradictory to the big-bang theory. The model of the universe envisioned by Steinhardt sees the big bang as merely a turning point on an infinite road."
This discussion has been archived. No new comments can be posted.

Big Bang or Cosmic Crunch? More

Big Bang or Cosmic Crunch?

Comments Filter:

  • Comment removed (Score:3, Funny)

    by account_deleted ( 4530225 ) on Thursday April 25, 2002 @10:45PM (#3413728)
    Comment removed based on user account deletion

  • if this is right, (Score:3, Insightful)

    by jnana ( 519059 ) on Thursday April 25, 2002 @11:00PM (#3413788) Journal
    then perhaps Nietzsche was right after all [rutgers.edu], as I've said infinitely many times before.
    • "This life as you now live it and have lived it, you will have to live once more and innumerable times more; and there will be nothing new in it, but every pain and every joy and every thought and sigh and everything unutterably small or great in your life will have to return to you, all in the same succession and sequence--even this spider and this moonlight between the trees, and even this moment and I myself. The eternal hourglass of existence is turned upside down again and again, and you with it, speck of dust!"

      Not necessarily. That would mean that everything would have to come back exactly to how it was.... and it doesn't have to. Just because the universe collapses and bursts out again doesn't mean that it does so in the same exact manner. The net energy in a closed system can be the same (zero) with an innumerable ammount of possible permutations... it doesn't have to be the same every time...
      • You're right, of course, but it's much more fun to try to wrap your mind around the possibility of eternal recurrence as Nietzsche conceived it. How strange your world becomes when you consider the possibility. Really. Try it for a couple of hours, and you will notice a definite shift in consciousness.

        Nietzsche didn't spend the last 11 years of his life in an asylum for nothing.

        • absurdity should not for neither austerity nor advocacy make.

          neitzsche must be studied as a mind chocked to the brim with 19th century delusions of grandeur; or to what you suggest, it will quickly become an exercise in the deceptively sublime act of tedious fancy. these notions of bogus social and cosmological assumptions presuppose a greatly bewildering ignorance of what has become over time pedestrian. giving a quick nod as to what passes for intellectual discourse these days perhaps gives one as yourself pause to think of the bygone error of classical philosophy and its most tumultuous period in recent memory (the rather rigid backbone for social stigma and taboo shattered) as to be the proper outlet for the cultivation of these "tools of consciousness" that you speak of so passionately.

          i suggest timothy, dr timothy leary.

          i don't know why but i think it would be a better direction.

          I love double negatives

    • Nietzsche was an alien stuck on Earth, with nothing better to do.
  • ..begin to grasp. The human mind, IMHO, cannot truly appreciate the many paradoxes that come with the terms "infinite" and "eternal." Indeed, the very use of those terms is seen by some as negating many of the very scientific laws that we currently live our lives by.

    Wrap your mind around it for a bit and try to appreciate what is being said here. The universe will expand and contract.. but what force is causing the expansion and contraction? Is it a natural extension of some force that we've yet to appropriately measure?

    And no, I'm not spouting about God. I simply like to point out holes in the "scientific" world we live in. :)

    .:|T|:.
    • The universe will expand and contract.. but what force is causing the expansion and contraction? Is it a natural extension of some force that we've yet to appropriately measure?

      Well because there is a gravitational force between all matter within the universe, no matter how far. So eventually all matter will form into massive clumps. Even if the last 2 remaining clumps are really really really really far away (really) from eachother, there will still be a small gravitational attraction toward eachother. It will take eons for them to come together again, but it will happen... at the center of the universe.
      • but these gravity theories apply mostly to matter, don't they? how does this apply to time and other "variables"?
        • ....what does time have to do with matter collapsing in on itself again?

          What other "variables" are you talking about?

          • Re:Infinity is a very difficult concept to even.. (Score:1, Interesting)

            by Anonymous Coward
            Humans are starting to think of the universe in wrong ways. My main beef is with time. People think of time as a physical dimension that is effected by matter.... this, is only partially true.

            They have sent up jets with atomic clocks to test einsteins theory of gravitation effecting time, and they think of it to be correct. The more gravity, the slower time moves. But is it really making a change to some 4th dimension, or just the speed at which the subatomic particles within matter move? ....the latter is certianly acceptable. Since matter slows down, then "time" relative to that slowed matter would infact slow....

            • (Disclaimer: IANAP, although I'm enamoured with the topic.)

              Humans are starting to think of the universe in wrong ways. My main beef is with time. People think of time as a physical dimension that is effected by matter.... this, is only partially true.
              They have sent up jets with atomic clocks to test einsteins theory of gravitation effecting time, and they think of it to be correct. The more gravity, the slower time moves. But is it really making a change to some 4th dimension, or just the speed at which the subatomic particles within matter move? ....the latter is certianly acceptable. Since matter slows down, then "time" relative to that slowed matter would infact slow....

              It's not just subatomic particles that slow down, which is Einstein's true stroke of brilliance. Einstein began down the road of Special Relativity by postulating that Newton's Principle of Relativity -- no matter where you are in the universe, the laws of physics are the same for all inertial (constant velocity) frames -- is correct. One of the laws of physics, courtesy of Maxwell's Equations, requires that the speed of light in a vacuum, c, is a constant. So, if both of these postulates are correct, then everyone will agree on the value of c in all inertial frames.

              This deserves some illustration. Suppose you're on a hypothetical train traveling at a constant velocity of 0.5c towards a friend, and you point a flashlight straight forward and turn it on. You perceive the beam of light as traveling toward your friend at speed c; however, your friend sees the beam of light as traveling toward him at speed c, and not speed 1.5c. How can this be?

              The answer that Einstein came up with, and the only known set of physical laws of motion that is consistent with both Maxwell's Equations and the Principle of Relativity, requires that your friend sees you as flowing through time at a slowed rate, whereas you see him as the one who is slowed down. With some extra geometry not far beyond a high school math student, it's not hard to prove that the length of (you|your friend) must contract; also, some modifications to Newton's Laws are required in order to make the laws of inertia and momentum self-consistent, making (you|your friend) appear to have more mass.

              It is an inescapable conclusion of Special Relativity that the actual flow of time slows down -- General Relativity, the theory which tied SR and gravity together while introducing time as a 4th dimension, is not even required to prove this result. The very CRT that you're using to view this article right now could not possibly exist if Maxwell's Equations were grossly wrong, meaning the only way to prove SR grossly wrong about the flow of time would be to disprove the Principle of Relativity -- by demonstrating that the laws of physics vary depending on where you are in the Universe!

              • no matter where you are in the universe, the laws of physics are the same for all inertial (constant velocity) frames

                Are you saying that light will always be moving at c?? Just because light enteres a medium, doesn't mean that time slows down because light is slowing down. The reason light slows down is because it has to exite every atom that it encounteres, then be thrown out again.

                They've even collected good evidence that the speed of light has changed over time... I'm really starting to doubt einstein.

                Suppose you're on a hypothetical train traveling at a constant velocity of 0.5c towards a friend, and you point a flashlight straight forward and turn it on. You perceive the beam of light as traveling toward your friend at speed c; however, your friend sees the beam of light as traveling toward him at speed c, and not speed 1.5c. How can this be?

                Take a jet for example. Say it it traveling at mach 2, and it fires a missle in which the missile maximum speed is mach 5. Now there is a stationary SAM site on the ground that will be blown up in a little bit... but the SAM site sees the missle coming at him at mach 5, and not mach 7. How can this be? Because you're missing the obvious....

                Light does have it's speed limit. The easiest explanation for that would be a drag in the ether that keeps it from exceeding that speed.

                You perceive the beam of light as traveling toward your friend at speed c

                That is the mistake in the example... It is trying to prove relativity, but without relativity, that sentence would be false... You can't prove something by initially assuming that it is true; using the theory within the explanation for the theory.

                Didn't Einstein fail math?

                • They've even collected good evidence that the speed of light has changed over time...

                  Umm... Please back that statement up.

                • no matter where you are in the universe, the laws of physics are the same for all inertial (constant velocity) frames
                  Are you saying that light will always be moving at c ?? Just because light enteres a medium, doesn't mean that time slows down because light is slowing down. The reason light slows down is because it has to exite every atom that it encounteres, then be thrown out again.

                  That's why I mentioned that c is the speed of light in a vacuum. The speed of light in a non-vacuum medium is slowed down, to c divided by the refractive index of the medium (1.33 for water, for instance). Basic optics, known well before Einstein's time.

                  They've even collected good evidence that the speed of light has changed over time... I'm really starting to doubt einstein.

                  Citations, please?

                  Suppose you're on a hypothetical train traveling at a constant velocity of 0.5c towards a friend, and you point a flashlight straight forward and turn it on. You perceive the beam of light as traveling toward your friend at speed c; however, your friend sees the beam of light as traveling toward him at speed c, and not speed 1.5c. How can this be?
                  Take a jet for example. Say it it traveling at mach 2, and it fires a missle in which the missile maximum speed is mach 5. Now there is a stationary SAM site on the ground that will be blown up in a little bit... but the SAM site sees the missle coming at him at mach 5, and not mach 7. How can this be? Because you're missing the obvious....

                  I'm not the one missing the obvious. Unfortunately, Slashdot won't let me draw some ASCII art to explain, but I'll try and describe it in terms that you'll understand... remember that airspeed is speed relative to the air, and that air is essentially stationary compared to the ground when you're talking about Mach speeds.

                  From the perspective of the SAM site, the plane is moving at speed Mach 2 angle 0 with respect to the ground, then launches a missle that quickly assumes a path in which it is traveling at speed Mach 5 angle 315, which happens to be perfectly aimed such that it will impact the SAM site.

                  From the perspective of the plane, the SAM site is zooming underneath at speed Mach 2 angle 180. It launches the missle (let's presume it's guided), then observes as the missle fires up and assumes a path of travel with speed Mach 3.57 angle 293.5. The missle looks like it will fall short, except that the SAM site rushes underneath the missle just in time to be hit. Stupid SAM site!

                  In the train example, we have a train traveling at speed 0.5c angle 0. You are standing on the train, and your friend is directly in front of the train by a safe enough distance that he'll be able to sidestep the train when it gets close. So, from your perspective, your friend is rushing toward you at speed 0.5c angle 180, and the beam of light is rushing away from you at speed c angle 0. What does your friend see? According to Newton's mechanics, he should see you rushing toward him at speed 0.5c angle 0, and the beam of light should be traveling at speed 1.5c angle 0 (simple trigonometry -- you add two vectors with the same angle by adding their magnitudes). In reality, as confirmed by countless experiments, the most famous of which are known as as the Michelson-Morley experiments, your friend perceives the beam of light as traveling at precisely c. If you fire a railgun from the train with a slug that travels at speed 0.5c angle 0 relative to you, then your friend will see the slug traveling toward him at speed 0.8c angle 0. These results have been confirmed by many, many experiments, so the burden of proof is on Einstein's doubters to show -- using repeatable and accurate experimental methods -- that an alternative explanation can exist. The physics department at the University of California at Riverside has an excellent site [ucr.edu] introducing physics, including these [ucr.edu] two [ucr.edu] pages that explain why the ether theory from the late 19th and early 20th centuries is thoroughly debunked and cannot be modified to fit the facts without becoming an unfalsifiable hypothesis (i.e. a matter of faith).

                  Light does have it's speed limit. The easiest explanation for that would be a drag in the ether that keeps it from exceeding that speed.

                  Again, see the above links for an explanation of why ether theory cannot be falsified if it is modified to be consistent with our existing knowledge.

                  You perceive the beam of light as traveling toward your friend at speed c
                  That is the mistake in the example... It is trying to prove relativity, but without relativity, that sentence would be false... You can't prove something by initially assuming that it is true; using the theory within the explanation for the theory.

                  The statement assumes that relativity is true, but it's a testable and falsifiable statement that, if it were false, should be trivial to debunk. Despite multitudes of measurements and experiments, especially by the people who passionately desired to show it to be false, that very statement has not been found untrue even once.

                  Didn't Einstein fail math?

                  Yes and no. He understood math quite well, but due to dyslexia he couldn't deal very well with the rote memorization and mechanized learning required of him by the school system. He eventually learned to deal with it well enough to get excellent grades.

                  • They've even collected good evidence that the speed of light has changed over time... I'm really starting to doubt einstein.

                    Citations, please?

                    I'm not sure what theories they were, but my physics professors have told me that Einstein has been proven wrong before.

                    Gave the link above in another reply... but here it is again. I thought it was pretty damn big news and most people who knew their physics would know about it... I'm just goin into college and I knew. :\

                    http://www.nytimes.com/2001/08/15/science/15PHYS.h tml [nytimes.com]

                    Here's another one that I've saved

                    http://www.trdtech.com/2/personal/matrixsupport/ [trdtech.com]

                    I don't think any real revelations or changes have been made, or need to be made for that matter, to our current theories, but it's quite interesting and it does lead to more thining; showing us that there is still much to be learned.
                    • I'm not sure what theories they were, but my physics professors have told me that Einstein has been proven wrong before.

                      Interesting links, although I won't be holding my breath while the results are checked. As one physicist is quoted in the NYTimes article as saying, "You have to get down on all fours and claw through the details to see such a small effect." However, even if the results are accurate, it won't mean that Einstein's General Theory of Relativity will be tossed out the window like a used tissue.

                      Just as Newton's physics are mostly right, when restricted to the realms where they are applicable, Einstein's physics are accurate to such a degree that any new physics will only need to be dragged out for the realms where Einstein's physics are found to be inapplicable. The Standard Model of Physics can be summed up as "use Quantum Chromo Dynamics for the EM, weak, and strong forces; use General Relativity for the gravitational force". The incompatibility between GR and QCD is quite striking, but the candidates to replace the Standard Model seem well on their way to making GR's tensor calculus look like simple algebra, making it likely that GR will still be the theory of choice for situations where it is mostly right.

                • Heh, nice. You would have made a fine ancient greek scientist. Pity we have moved on since then.
            • >Humans are starting to think of the universe in wrong ways. this is an illutration of you missing the point. relitivity is that there is no right way. it is dependant on the perspective. all pespectives are valid.\ >The more gravity, the slower time moves. But is it really making a change to some 4th dimension, or just the speed at which the subatomic particles within matter move? .... the particles that carry out the effect of gravity are called gluons. their effect ( or any thing's )on any body is reletive to the speed of light, which is to say thaton a particle level, the speed of light is constant, no matter what speed you are observing it from. if you are traveling at a speed that is faster than meto the speed of light in relation to ( for example ) the planet earth, the particles that make up a beam of light have more distance to cover from my observational veiw point, and since it it covers that relative disance in the same amount of time, from my veiw, the time spent in your travels is relatively less than the time it would take me to travel the same distance at a relativly slower speed.
        • Gravity has everything to do with time.

          Space&Time and Mass&Energy are the "variables" of gravitational theory.
      • Not necessarily. The term escape velocity is exactly the opposite of what you are saying. Escape velocity is the velocity an object needs relative to another to never fall back into it. The more gravitational attraction there is, the higher the velocity is needed to escape. This is why the amount of mass in the universe is so closely related to wether the universe will expand forever or collapse again. If there isn't enough mass, there won't be enough attraction to slow the expansion to a stop and reverse it.
    • Bah

      Take some analysis and come back when you understand that the word "infinity" encompasses many different meanings and amounts, and that some of these are very well understood.

      Take some upper level physics and come back when you understand that whenever "infinity" is in an integral or calculation, it is an approximation.

      Science and math is very simple, it is the philosophy and epistomology that is complicated without certain solution.
    • To me though, infinity is much easier to grasp than negative infinity. To say there is no end, as unfathomable as it is, is much easier to comprehend than to say there is no beginning.

  • Not a new theory (Score:3, Interesting)

    by quadong ( 52475 ) on Thursday April 25, 2002 @11:04PM (#3413800) Homepage
    This is hardly a new theory. The only thing which I see that makes it distinct from the age-old theory with the same outline is that it invokes dark matter as part of the mechanism. Hopefully, if presented in scientific language rather than yahoo-interview, it has some interesting new twist, but I'm just not seeing it here.

    Also, he says "When it's changing slowly, it's gravitationally self-repulsive and when it's changing fast, it picks up speed, it's gravitationally self-attractive". It's slow and repulsive now. What is supposed to ever make it speed up in the future since it's own existance is what is making it slow now?

  • Facts are... (Score:2, Insightful)

    by quantax ( 12175 )
    I agree that we should definately continue looking for answers for this old question (the origins of the universe), but the fact of the matter is that any conclusion we come up with is more or less assumed from postulated data. This includes yesterday's post regarding the age of the universe. We can examine the universe from our position in it, but its impossible to make 100% factual judgements about certain things such as the mass of the universe, etc since there is a great deal we cannot see, and whatever is hiding behind what we can't see is included. Our data pool is limited due to our lack of ability to leave our planet or solar system in any 'real' sense. Again, we should not stop for that would be foolish, but we must remember that these findings are not fact, but theory and should be thought as such.
  • We are the dust of long dead stars.±

    Excerpts from interview of Sir Martin Rees, Astronomer Royal of England by Claudia Dreifus, New York Times, April 26, 1998

    but it appears Stars are the dust of long, long dead us?
  • the universe never began and will never end, driven forever to expand in a series of monster explosions and contract every eon or so in a cosmic crunch. This is directly contradictory to the big-bang theory.

    In a nutshell... no, it doesn't contradict the theory. It just gives an explanation as to how that primeval atom came to existance.... by everything crunching together.

    There are tons of theories about how the big bang happened. One about some cracked out idea of the 5th dimension crashing into the 3rd or some shit.... I think we make it harder than it really is.

  • The Ekpyrotic Theory... (Score:5, Interesting)

    by cybrpnk ( 94636 ) on Thursday April 25, 2002 @11:21PM (#3413867)
    There's a lot of theories about alternatives to the big bang besides the one mentioned in the Yahoo article. The main one that is getting a lot of interest in scientific circles isn't this new one in the Yahoo article. Instead, it's the so called Ekpyrotic [space.com] theory, with the name coming for the Greek word for fire. It is so intresting because it brings together two disparate areas of physics: inflation [susx.ac.uk] and M branes [ucsb.edu]. Inflation is a weird concept that says the universe expanded from the diameter or an atom to the size of a grapefruit almost instantly - required to explain the way galaxies are clumped and clustered in the sky we see today and first postulated by a guy named Alan Guth [bkstore.com]. M branes are an offshoot of string theory [superstringtheory.com] postulated by Ed Whitten [st-and.ac.uk]. There's tons of stuff on these topics on the web; all of it is facinating, enter any of these terms in a search engine and keep reading. Next stop, Google [google.com]...
    • Lee Smolin talks about an evolutionary model in The Life of the Cosmos [amazon.com] which has the great advantage, for those who can get their head around it, of not requiring any assumptions about special conditions just arising out of nowhere, which is to my mind indistiguiushable from always having been there.

      Because we can't really escape them here, we have a lot of trouble contemplating anything at all which does not involve space, time, energy nor matter. An evolutionary universe gets us past this, not because it is concerned about survival, but about fecundity of the production process whereby black holes rebound to form disconnected big (and maybe sometimes little) bangs, then extrapolating this process back till when there was truly nothing except the possibility.

      Granting William of Occam an oversized razor, it would surely favour Smolin's idea of evolution from a state where the only certainty is that nothing is unstable to the world we find ourselves in; rather than Ekprotic Theory, any of the many attempts to revive the steady state corpse, the quantum theorists' many world interpretation or "intelligent design".

      Cycles never truly come back to their starting point.
    • From the first article you linked, I thought this was pretty funny:

      "It's almost crazy enough to be correct," says Michael Turner, a longtime University of Chicago cosmologist who is familiar with the theory. He added that "when you're trying to crack a really hard problem, you need a crazy idea."

      Turner said astronomers have reacted with great excitement to the new theory, in part because the idea of alternate dimensions is largely new to most of them.

  • Read about this in the Elegant Universe.... (Score:4, Informative)

    by anthony_dipierro ( 543308 ) on Thursday April 25, 2002 @11:23PM (#3413871) Journal
    Here's a summary [mcgoodwin.net]. I don't have the book any more so I can't quote, but notice in the summary of chapter 10 where the summary reads "When shrinkage to below the Planck length is attempted, the crunch becomes a bounce."

  • First of all (Score:2, Informative)

    by dalutong ( 260603 )
    I've believed exactly this for quite some time now.

    Secondly, this doesn't go directly against the big bang theory. the big bang created _this_ universe, yes, but before it were an infinite amount of "big bangs" and "big crunches."

    doesn't conflict, just tells the whole story.

  • Contradictory to the big bang theory? I thought this was a part of it. Unless I either misunderstood this theory, or misunderstood the big bang theory, I always assumed that the big bang theory already said that everything blew out at some point, came back together, blew out, came back together, in an infinite loop. Am I missing something?

    • Re:Errrr... (Score:2, Insightful)

      by adminispheroid ( 554101 )
      Steinhardt makes much of the "singularity" in the big bang theory, but in fact nobody understands the equations of state of matter past a certain extreme of pressure and temperature. So as you try to extrapolate towards earlier and earlier times, your understanding gets vaguer. See Weinberg's "The First Three Minutes" for a discussion of this. So this part doesn't disagree with the big band theory, Steinhardt just thinks he can fill in some new parts.

      He also seems to think he has an alternate solution to the flatness problem. This is the puzzle that according to gravitational theory, the curvature of space could be anything, but observationally, the curvature is zero. Seems like an odd coincidence. Guth came up with the inflation theory to explain this -- Steinhardt has another theory.

      So you're right, it's not contradictory to big bang theory. But it's not really part of it either.

  • The following hypothesis has been thoroughly vetted at many cocktail parties, so its' credibility and clarity of concept is unassailable:
    Here's the deal.
    There _was no big bang_. The universe is _not_ expanding.
    "Huh? I hear you say. "But, but what about red shift? The hubble constant?"
    Simple. Two words: General Relativity.
    If the universe stretches out infinitely in all directions, is of a density similar to here everywhere, and somehow replenishes matter lost to black holes and ..stuff.. by a mechanism that we don't understand yet, then the aggregate mass (infinite with a big I) at tremendous distances from us would be sufficient to bend space time in such a way so as to make it *appear* that everything is else is moving away from us. No matter where you went, when looking out to the 'edge' you'd see red shift all the way down to infinitely long wavelengths.
    The universe, in effect would appear to have an 'event horizon'.. a 'Black Sphere', if you will, beyond which nothing would be visible.
    Oh, this idea would explain all that pesky 'background radiation" too.
    Of course, measuring distances gets to be a real bear, but that's outweighed by being able to learn cool stuff about time-space geometries by playing around with the red-shift data viewed in a new analytical framework.
    So there you have it.
    When do I get my grant :)
    • You think that is simple, check this false explanation out

      "Photons naturally loose energy over time, and thus redshift over long distances."

      It is so simple and so wrong, but it could seriously fuck up the understanding of everything.
      • I see what you're saying, dude, but I was actually semi-serious.
        *I* was the guy spewing those speculations at those cocktail parties.
        General Relativity actually CAN explain apparent Expansion of the Universe(tm).
        It's Intuitively Obvious To The Most Casual Observer! (IOTTMCO)
    • If the universe stretches out infinitely in all directions, is of a density similar to here everywhere, and somehow replenishes matter lost to black holes and ..stuff.. by a mechanism that we don't understand yet,

      ...aaaand, stop right there.

      Matter isn't lost when it goes into a black hole; it ends up in the black hole's singularity, an infinitely dense point of matter in the center.

      Black holes are also thought to "leak" material in the singularity back out over time.
    • No matter where you went, when looking out to the 'edge' you'd see red shift all the way down to infinitely long wavelengths. The universe, in effect would appear to have an 'event horizon'.. a 'Black Sphere', if you will, beyond which nothing would be visible.
      Sounds like Doom and the 'hall of mirrors' effect. ;)
  • "Big Bang" "Cosmic Crunch" "M Brains" Is it just me, or are many astrophysicists hanging out far too long in the candy aisle while trying to think up names for thier pet theroies.

  • I've always said this. (Score:3, Interesting)

    by juju2112 ( 215107 ) on Friday April 26, 2002 @04:52AM (#3414660)
    I don't know much about physics, but i've always thought this. Really he's not disputing the Big Bang theory at all. He's saying that while it did occur, it was not the beginning of time. He's saying that in fact time has no beginning, or ending.


    This makes perfect logical sense to me. Why would time have a beginning OR ending? Just because human lives have them?

    • Bah. This is just another form of the "turtles all the way down" view of the world. If it's true, it just raises the question of how/when/why the whole lot started pulsating in the first place.
      • What?

        Would you care to reword that so I can understand it? :]

        • Re:I've always said this. (Score:2, Insightful)

          by p3d0 ( 42270 )
          The "turtles all the way down" reference is from a Brief History of Time by Stephen Hawking. You should read it. I was referring to any theory which simply begs the question. For instance, how did life evolve? Some answer that life didn't evolve on Earth, but rather came here from another planet. That simply begs the question, since it assumes that life already existed.

          So, if you want to stick your head in the sand, you can say the universe began when the previous one ended. But doesn't that leave us with the question of how this infinite sequence of expanding and contracting universes came to be?

          Thus, to me, the question of whether the universe is alternately expanding and contracting is mildly interesting, but not all that fundamental.

          • So, if you want to stick your head in the sand, you can say the universe began when the previous one ended. But doesn't that leave us with the question of how this infinite sequence of expanding and contracting universes came to be?

            Yes, but turn the argument around. If "something" caused the universe to come to be, it just pushes the question one level higher. What caused that "something" to be?

            Therefore, there has to be some "final level" that simply has always existed. That "final level" may or may not be our current universe.

          • So, let me see if I can sum up Mr. Hawking's logic:

            1: time is infinite.
            2: why is time infinite?
            3: 1 is wrong, because we can ask 2.

            The whole argument just seems silly. You can't invalidate one theory by asking a new question.

            • If that's what you think his argument is, then I must have presented it wrong, and you must have a very low opinion of Mr. Hawking.

              Read his book. Or, at least flip to the "turtles" part (I think it's near the beginning) and read that page.

    • >> Why would time have a beginning OR ending? Just because human lives have them?

      Could well be. Concious observation collapse the wave functions of the Universe into some eigenstates that would support a conscious observer so that it would observe and collapse the wave functions in order to support conscious...

      So, we are here because we are here because we are here ...
    • i agree with you

      time, to my understanding, is just a distance between two events, as witnessed by a beam of light...
  • From what I know .. since the theory of the big bang came was postulated the cosmic crunch theory has been around as well. I have read it in a number of book .. all of which I cann't recount but a few are Hawking's BHOT [amazon.co.uk] and McFadden's quantum evlolution [amazon.co.uk] SOme even going to the extent of in terms of quantum effect that time would seem to reverse for all living creatures .. a revese chaos if you will.

    Somebody please explain to me why it is all over the news now ??

  • Maybe "baby bangs" would be a better description.

    If you read the theory as described by the guy
    in the National Geographic story (linked from
    the yahoo site), he basically says that cosmic
    acceleration (the fact that, apparently, not only
    is the universe expanding, the rate of that expansion
    is increasing) makes everything spread so far
    apart that you basically have new vacuum that can
    spawn new big bang. I guess "big bangs"? I don't
    know, it was short on details. He calls this state
    of everything being spread so thin a "crunch"--it
    seems to me more like, well, butter scraped over
    too much bread (ok, that was just for fun). But
    "crunch" seems to me like everything collapsing back
    in on itself, where what he is saying is that things
    are just spread so far apart that you have the conditions
    for (a? many?) big bang(s?).
  • So folks, here it goes: a european engineer called Hannes Alfvén came up some time ago with this very lean theory that cleans up quite a bunch of esoterical paradoxes now commonly accepted ("...it HAS to be true...")
    He starts observing that electromagnetic forces are far stronger than gravity and removes the assumption that they don't take part in the cosmological interaction.
    Think about it, whenever we talk about cosmos we are considering only mass and gravity; so what about plasmas and ionized gas flows? Are they relevant only in neon lamps? Absolutely not, the Sun blows a huge amount of it on our very planet producing effects like the ionosphere, auroras, power grid failures and radio black-outs.
    What happens when we account for such current densities within galaxies and in intergalactic space? Ion flows generate EM interactions, current pinching (think about the definition of the Ampere), tranform kinetic energy in potential and shuttles it where the circuits close like in galaxy cores.
    Simulations of such free space EM-plasma interaction are stunningly similar to galaxy formations.
    Furthermore, cosmological dishomogeneities arise naturally from these forces without having to assume that some seconds after the BB foam bubbles of matter imprinted them before an even more improbable inflation.
    This cosmology is based on (or better, it also accounts for) Maxwell's equations, it doesn't pretend to reverse engineer God's bootstrap using sacerdotal elucubrations on unrepeatable experimental conditions. All you need to change is the scaling factor in your equations and the magnitudes comfortably extraced from your lab equipment match the data from astronomical observation.
    It's not all-encompassing, but hey, it's a theory well entrenched in the scientific method: think-experiment-rethink-experiment-... no metaphysical, no mystical truths to believe and most importantly no ultimate ones to sell.
    BTW, the chap in question isn't a crackpot scientist, actually he's a Nobel laureate.
    Have a look at it on google: plasma cosmology, Hannes Alfvén or check out
    ISBN 0-671-71100-8

    Ciao,
    Edo

  • A Brief History of Time (Score:3, Interesting)

    by bheilig ( 516136 ) on Friday April 26, 2002 @09:40AM (#3415320)
    I read this book by Hawking some time ago; I make no claims about understanding it. He mentioned several logical possibilities, which should summarize what everyone else has been saying in spurious posts...

    1. A beginning with no end. Our universe began from the big bang and, if the gravitational pull of the center is not large enough to overcome the momentum of the explosion, will continue to expand though infinity.
    2. A beginning with an end. The gravitational pull of the center can overcome the momentum of the explosion, resulting in a big crunch.

    These two only describe our observable universe. Time begins with each explosion and ends with each contraction. If the gravitational pull, which grows as the universal spheroid becomes more massive, can pull the mass smaller than infinitesimal (mathematically speaking, I guess) then a bounce occurs, resulting in another explosion.

    3. If the ratio of energy/mass remains constant with each explosion, then THE universe (not OUR universe) continues from -infinity to +infinity, as the article states.
    4. If the ratio increases every time, the explosion will eventually provide enough momentum to overcome the pull of gravity (case 2). We may be in this state now, or we may not.
    5. If the ratio decreases every time, then eventually the universe will be pulled into a point, with just enough energy to keep it there. Our universe may have this finite end, or it may not.

    This is the greatest .sig you've ever seen.
  • I thought they established that there isn't going to be a Big Crunch. They found that the expansion of the universe is accelerating, not decelerating. Am I working with old news here? Has that been disproven already? (I turn my head for a few minutes of Diablo 2, and they change the fate of the universe on me.)
  • Aside from questionning the expansion actually happening, could someone tell me what do we mean by universe expansion ?
    I wonder if we are talking about matter moving away like due to an original impulse, or if we are talking about universe "itself" (not really like the ether, but someting like "support for matter") expanding ?
    I'm talking about "void" being something after all (though not matter, but you know.. the "drawing board" where matter can be drawn and interact. his very drawing board can have its own geometry, properties etc.)
    I honestly don't know what do scientis mean when they talk about universe expansion, as I tend to 'view ' the unverse as a closed hypersphere (not really any good reason to do so but to put a stop to infinite recursive thoughts)
    I suppose (hope) the question is valid.
    I mean, I just read a few things around (obiously) but I think background radiation is caused by the original small size of the universe compared to the speed of light so that standing waves could be created or something like that. (ok maybe i just made it up..)
    Anyway, I also think I've read that everything gets appart from everything, any two galaxies far enough are getting away from any other at the same rate, so this isn't comaptible with an explosion scenario in which clearly, the farther points (diametricaly oposites) would show the greatest shift and the closer one almost none.
    So if this is the second scenario (or is this yet another one ??), how can we even relate it with the forces we can measure which only interact with matter ?(or not ? don't know about GR)
    Gravity, electromagnetism etc. can very well attract/repulse matter, but why would this have to contract the universe itself ?
    If i put small magnets, bound to the surface of a balloon and I start to inflate this balloon, the magnets will or will not collide collide if they attract themeselves better than i inflate the balloon, but they will not contract the balloon itself...
    Could anybody tell me what do cosmologists mean when they say "universe expands" ?
    Thanx....
  • Instead of thinking of the universe similar to a kernel of popcorn, I prefer to think of it more as soup.

    Popcorn would be the bang and crunch model--that is, if popcorn could crunch back into a kernel again. The individual particles (molecules, atoms, protons/neutrons/electrons, quarks, and so on) could represent super strings, galaxies, solar systems, planets, and such.

    In the soup model, the suns are blowing up and retracting all the time, but most everything just swirls and stays very active overall. This seems to more easily conform to the laws of conservation of mass and energy rather than two universe-wide events that keep occuring.

    The major whole I see in the soup model is the contstant introduction of energy from the stove. The universe would seem to have a finite amount of energy/matter. We haven't quite figured out gravity, but if the universe has a curved edge due to the general performance of gravity (tendency of seemingly all matter/energy to be attracted to all other matter/energy), energy never really could get an infinite distance from the mean center of the universe. Hence, the universe is curved as Einstein thought at some point because everything just swirls back in due to mutual attraction.

  • Stephen Hawking talks about this in A Brief History of Time. Carl Sagan talks about this in Cosmos. Lots of other people talked about this before them. For crying out loud, this very notion has been a staple part of Hindu mythology [ica.net] for hundreds of years.

    Is this by any chance related to the recent /. story about Mr. Steven Olson patenting swinging sideways [slashdot.org]?

  • Is it just me or does all of this theory sound like groping at some sort of explanation on how the universe works? I mean "dark matter", "dark energy" and the like are just ways of explaining what we really don't understand. IMHO it sounds to me like the theories on how the universe works are pretty shoddy at best. Logic would tell me that "dark matter" couldn't exist. And that the reason it does "exist" is because we made it up so that our current view of the universe would make sense when it is fundamentally flawed. I am definitely no astrophysicist and I don't make any claims at being one. I know that when we think about things on such a grand scale certain things don't apply anymore, but intuition and logic tell me that the simplest and most logical answer is typically the right one. Case in point would be the extinction of the dinosaurs. For years scientists speculated on the reasoning behind the extinction of the dinosaurs, until one day it occurred to someone somewhere that maybe an asteroid hit the planet and wiped pretty much everything out. That seems logical and reasonable. But if someone told me that some "dark apocalypse thing" came and wiped out all the dinosaurs I would be a little more hard pressed to believe it. I am sure that there are plenty of people that are going to try to explain why I am wrong and why "dark matter" or whatever must exist but the logic of it defies me. Thoughts?

Slashdot Top Deals

Beware of Programmers who carry screwdrivers. -- Leonard Brandwein

Close