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Space News

Einstein's Biggest Blunder That Wasn't 303

jose parinas writes "The genius of Albert Einstein, who added a "cosmological constant" to his equation for the expansion of the universe but later retracted it, may be vindicated by new research. The enigmatic "dark energy" that drives the acceleration of the Universe behaves just like Einstein's famed cosmological constant, according to the Supernova Legacy Survey (SNLS). Their observations reveal that the dark energy behaves like Einstein's cosmological constant to a precision of 10%."
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Einstein's Biggest Blunder That Wasn't

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  • by $exyNerdie ( 683214 ) on Thursday November 24, 2005 @01:06AM (#14106075) Homepage Journal
    The cosmological constant is an extra term in Einstein's equations of general relativity which physically represents the possibility that there is a density and pressure associated with "empty" space. The inclusion of this vacuum energy term can greatly effect cosmological theories.
    http://super.colorado.edu/~michaele/Lambda/lambda. html [colorado.edu]

    http://en.wikipedia.org/wiki/Cosmological_constant [wikipedia.org]

    • by ChadN ( 21033 ) on Thursday November 24, 2005 @02:17AM (#14106306)
      "Affect"... "Can greatly affect"... 'effect' is a different word, with a different usage.

      An informative post, and I'll accept moderator punishment for grammar nazi-ism.
    • Yet more "science" aiming to push baby jesus out of my fifteen childrens' school. This country was founded on gawd! Take your heathen "knowledge" to some other third-world country, you sick freaks!
    • Density, exactly... (Score:5, Interesting)

      by rmdyer ( 267137 ) on Thursday November 24, 2005 @03:42AM (#14106540)
      That's my take on modern cosmology. That there exists this one substance, the vacum substance, the stubstance of space-time itself. It can be imagined as a drop of water, or equally as a cloud of moisture. It contains volumes within it that are "denser" than other volumes. We say that there is "more space" (or less?) within those volumes. All "material" goods are then just some kind of configuration of this "space-time" stuff. I think also that based on quantum mechanics, and the "Beckenstein bound", material within a given volume can be realized in much the same way pictures are made up of "pixels" on a computer screen. Think of it. Your computer screen resolution determines all objects that are "realizable" within its resolution. The Beckenstein bound then formulates a given volume for space-time in which objects of a given size can fit. The relationship of the "density" of space-time then should directly influence the Beckenstein bound such that, if there is "more space", then there should be the possibility of a larger number of possible quantum states within the abstract volume of space-time.

      If you had a glass sphere the size of a basketball, what are all the material objects that are realizable within that space? Well, we can put car keys, pens, small animals/insects, etc. But we cannot put a house inside a basketball right? Well maybe a doll house. But how would we go about putting a real house in a volume the size of a basketball? Simple, just increase the density of space-time within that abstract volume. That will increase the number of quantum states possible just like increasing the resolution of your computer screen. But what do we mean when we say "space is dense"? Since the vacum is matters "opposite", we would probably conclude that space would be "denser" where matter is not. So we might say that within a "black-hole" there is theoretically "no space". A black hole would then indeed be a hold within space-time, a tear in the fabric of reality for example. But this may not be the case. It could be that a black hole is a place were the density of space is so high as to be exactly "solid" space-time. In this respect matter flows into a black hole and then becomes converted to "space-time", which then slowly and inexorably flows outward. Space-time is being generated by a black-hole by the conversion of matter to space-time.

      If space-time is a substance of some kind, and all matter is just some configuration of it, then that would explain why we cannot move faster than light. This would be the case if we were somehow made of configurations and vortices of "air". Since we being made of "air", we could not move faster than sound right? Of course doesn't the speed of sound vary with the density of air? Would not the speed of light vary with the density of space-time? Of course it does, this was Einsteins great find, that light travels along a space-time geodesic. The geodesic caused by the "density" of space-time.

      Based on all these analogies, I don't see why we have to think about the fourth dimension at all. We just need to imagine space-time as a volume with varying densities. Within a high density of space-time, you can have more matter, and more quantum states. It is abstract I know, but for my mind it works. Is there a reason that these analogies can be viewed as "wrong"? I'm willing to take an alternate view.

      • Using density as an analogy, as you have in your post, I couldn't help be reminded of the old TARDIS. By increasing the effective density of space-time within a police-box, you could possibly fit enough inside it to resemble that famous timeship.

        Who knows - perhaps the travelling in time and the density of space-time have further connections, even?

      • by Trebonius ( 29177 ) *
        There is the theory of the Moebieus: a twist in the fabric of space, where time becomes a loop. Where time becomes a loop. Where time becomes a loop. Where time becomes a loop. Where time becomes a loop...
        -- Worf
      • by earthbound kid ( 859282 ) on Thursday November 24, 2005 @10:38AM (#14107444) Homepage
        How would you know that space-time was denser? When you move your ruler inside of it, wouldn't the ruler's size fit the density of space, showing in the case of the basketball that can fit a house that it actually is the size of a house, since it can fit a house's worth of rulers inside? Since space is just a measure of distance and distance is a measure of chemical bonds strengths over space and whatnot, it seems like it would be hard to measure space to be any more or less than 1/1.
        • How would you know that space-time was denser? When you move your ruler inside of it, wouldn't the ruler's size fit the density of space, showing in the case of the basketball that can fit a house that it actually is the size of a house, since it can fit a house's worth of rulers inside? Since space is just a measure of distance and distance is a measure of chemical bonds strengths over space and whatnot, it seems like it would be hard to measure space to be any more or less than 1/1.

          You'd measure it by ext
        • by rmdyer ( 267137 )
          You are correct. The problem we have here is that these "volumes of density" are abstract. But your reasoning is exactly the problem we encounter with the Michelson-Morley Experiment right? We seem to find that light is the same speed in all directions, proving that the "ether" doesn't exist. The basic problem with the "old ether" is that ether was some kind of substance. I find this view of ether silly since space-time itself isn't a "substance" it is the opposite of substance, of matter itself...it i
        • by Myopic ( 18616 )
          how about detecting it without measuring it directly, like when we watch light from far away in the universe bend around various cosmic objects.

          also, is that guy describing ether? sounds like ether to me.
    • by gilzreid ( 95884 ) on Thursday November 24, 2005 @04:04AM (#14106595) Homepage
      These stories always say it was Einstein's great blunder and it has been vindicated, but it really hasn't. The reason Einstein put it in was that he couldn't find any solutions to his equations that resulted in a static universe. (At the time, Hubble's revolutionary results on the recession of distant galaxies had not been completed, so it was thought the universe must be static) All of his model universes were expanding or contracting. So he added the constant to balance out the contraction in his favoured model (which was also closed, another historical assumption in cosmology that has been disposed of).

      OK, but the cosmological constant we see now is being used to explain the _acceleration_ of the universe, nothing like what Einstein put the constant in for. His blunder wasn't really the constant, it was the assumption that the universe was static, which turned out to be totally wrong.

      But you have to admire Einstein - out of pure thought and mathematics he produced a theory which is still held up as a foundation of modern physics, even though practically every cosmological observation was made years after he published it (and all the observations have supported the theory to great accuracy). Compare this to, say, quantum mechanics, where many theorists struggled for decades to explain observations that had already been made, and Einstein's one-man theory is truly impressive.
      • Actually, it was Einstein himself who called the "cosmological constant" his greatest blunder. And I think you point out the reason in your post why Einstein thought it was a great blunder; Einstein added the constant to his equation not because the physics demanded it but because of his own "prejudice" about the making of the universe. Remember, all what was needed for formulating the theory of special relativity was understood first by other great scientists like Lorentz and Poincare, but it was only Eins
        • And it's only in the last month that I have ever heard of Poincare. He seems (like so many others) to have been on the cusp of greatness, but not quite made it. Still, reading his story, and how he compares to Einstein, reminds me that Einstein is great because he stood on the shoulders of giants. I am also reminded that science and philosophy are intertwined much more than most people realise.

          BTW, is your sig a quote from "Benson"?
          • Poincare was great, but his true greatness was in maths not in physics. Of the more well known things he did was related to topology and dynamical systems, with discoveries that point forward to what is today often called chaos theory.

            Of course, had Poincare discovered the special theory of relativity his name would have been as great in physics as in maths, but few, even among people of Poincare's stature, can claim to be big in more than one field of science. For instance, Einstein was never a great mat

  • Awesome (Score:3, Insightful)

    by CriminalNerd ( 882826 ) on Thursday November 24, 2005 @01:08AM (#14106083)
    Will Einstein's genius never cease to amaze us post-humously? Probably not.

    This will be a great thing for students to look up if they are doing (or going to do) relativity in school.
    • Re:Awesome (Score:5, Interesting)

      by OzRoy ( 602691 ) on Thursday November 24, 2005 @01:15AM (#14106115)
      Einstein put in the constant as a fudge because he wanted his equation to match the data. At the time people were not aware of the exanding nature of the universe. I don't think he ever liked using the constant, and was relieved when it turned out it wasn't necessary. Everything was neat again.
      • Actually Einstein was chagrined that he included the cosmological constant. He could have postulated the expanding nature of the universe years before Hubble measured the red shift of distint astronomical objects. He was disappointed that he used this factor to make his equations fit the static universe model that was the standard of his time.
    • He impressed me before I'd even heard of humous, let alone eaten it.
  • Dark matter ... (Score:2, Informative)

    by karvind ( 833059 )
    Well GR still explains the dark matter [slashdot.org].

    Can anyone explain the idea behind dark matter and dark energy ? I mean if it is just a mathematical problem or has some experimental justification as well.

    • Re:Dark matter ... (Score:4, Informative)

      by Lisandro ( 799651 ) on Thursday November 24, 2005 @01:20AM (#14106139)
      I'm no physicist, by a long shot :) but the idea of dark matter comes from the fact that some phenomenons on the the visible universe (rotation of galaxies [wikipedia.org], particularly, IIRC) can't be explained with our current knowledge of physics - there's simply not enough matter for them to behave like they do. Hence, we now have this notion of dark matter [wikipedia.org]; mass that affects other mass (gravity and such)... but can't be detected by conventional means. It's a stopgap to make measurements fit our current theories, as i see it.

          Dark energy [wikipedia.org] is more of the same, and tries to account for the visible expansion of the universe.
      • Re:Dark matter ... (Score:2, Informative)

        by Anonymous Coward
        ...[dark energy] tries to account for the visible expansion of the universe.
        [dark energy] tries to account for the visible acceleration of the expansion of the universe.
        • I am certain someone thought about this before so there must be some good arguments about what I am thinking. If anyone knows them I would appreciate being answered.
          Why can't this acceleration be attributed to the shape of the universe itself instead of by some new force pushing on the matter ?
          That is, if I understand correctly, gravity itself is not taken into account for this observed acceleration because of the expanding nature of the phenomenon, where we would be expecting the opposite.
          But what if, i
    • Re:Dark matter ... (Score:2, Informative)

      by Anonymous Coward

      Well GR still explains the dark matter.

      No, it doesn't. [slashdot.org] Even if their result was right, which it doesn't seem to be, it never explained all the observations which imply dark matter; it only accounted for galactic rotation curves.

      Can anyone explain the idea behind dark matter and dark energy ? I mean if it is just a mathematical problem or has some experimental justification as well.

      Of course it has experimental justification. That's why it's such a big deal.

      Dark matter is, well, non-luminous matter. The o

    • Re:Dark matter ... (Score:5, Informative)

      by Jerry Coffin ( 824726 ) on Thursday November 24, 2005 @01:59AM (#14106253)

      Can anyone explain the idea behind dark matter and dark energy ? I mean if it is just a mathematical problem or has some experimental justification as well.

      Fair Warning: what follows is a really simplified version of reality, and at least a couple of points go beyond simplification to the point that they're arguably flat out wrong. If somebody wants to correct part or all of this, please feel free, but if you do so please try to keep with the spirit of actually explaining things so they're understandable.

      The situation with dark matter is simpler than dark energy, so we'll start with that.

      We've observed a certain amount of matter in the universe. Those observations lead to a rough estimate of what the total amount of matter in the universe might be.

      Now, there was a certain amount of energy released in the big bang. For quite a while, it was assumed to be the primary reason that the universe was expanding. I.e. there as a big explosion, and matter went flying off in all directions (and we're basically just living on a bit of shrapnel from that explosion).

      Now, if there was enough matter in the universe, the gravity between it would eventually slow it down, stop it, and finally start it contracting back together. That was a rather attractive idea -- that the big bang wasn't a one-time thing, but that we just happened to be seeing evidence of the most recent occurrence.

      The problem was that our estimates of how much matter there was in the universe came out well below what was needed for there to be enough gravity to make the expansion stop and eventually reverse.

      One answer that was postulated to that was dark matter -- a lot more matter out there that we couldn't see, so it wasn't being figured into our estimates of how much matter there was in the universe. Therefore, a lot of people spent a lot of time and energy trying to find ways to observe a lot more matter than we had previously. To some extent they succeeded -- better telecsopes, observing techniques, etc., have allowed us to observe quite a bit more than we had previously.

      By this idea, however, almost regardless of the exact amount of matter in the universe, the gravity should act to slow down the expansion over time -- i.e. the energy pushing things apart was all expended during the big bang, and now gravity should be acting in the general direction of pulling things back together again or at least slowing down the rate at which they're moving apart.

      That doesn't fit reality though. In reality, it appears that the expansion of the universe is actually accelerating. The original theory was that the expansion was due to energy released during the big bang. If that was the case, the expansion of the universe should basically just be "coasting", and there's no way it could be accelerating.

      The obvious way for the expansion to accelerate is to figure that even though we generally think of the space beyond the edge of the universe as a complete vacuum, devoid of matter or energy, that there really is a little bit of something there afterall, and being a little bit of something (energy or mass) it has some gravitational pull on the matter that we think of as part of the universe, so it's more or less pulling the universe apart -- i.e. accelerating the outward movement.

      Given that the expansion of the universe is accelerating (which certainly seems to be accepted as fact right now anyway), it seems to me that the existence of the cosmological constant isn't really the question. The primary questions are 1) what is its exact value, and 2) where exactly does it come from.

      If you read the article from the University of Colorado cited elsehwere (for one example), you can find both some estimates of upper and lower limits on the value, and at least one possible explanation for its source. I've heard at least one person give what sounded (to me) like a different explanation of its source, but it wouldn't surprise me too much i

      • Re:Dark matter ... (Score:5, Informative)

        by Coryoth ( 254751 ) on Thursday November 24, 2005 @03:55AM (#14106578) Homepage Journal
        I'll expand on the issue of dark matter a little. It's still rather simplified, but it is more to the point on the issue of dark matter particularly.

        The original problem that lead to postulating dark matter involves observations of galaxies. Galaxies rotate and physics makes predictions about the orbital velocity of stars in a galaxy based on their distance from the centre of the galaxy. The problem is that these predictions don't square very well with observations. In general observations show stars distant from the center of the galaxy orbiting much faster than expected. You can express this in terms of rotation curves [wikipedia.org] making the problem relatively clear. The proposed solution to this is to assume that there must be extra unobserved (hence dark) mass providing extra gravitational energy, and thus extra orbital velocity, to the more outlying stars.

        There are other theories to explain the observations such as Modified Newtonian Dynamics [wikipedia.org], but they tend to run into their own problems, and currently aren't anywhere near as widely accepted as the dark matter solution.

        Jedidiah.
        • Re:Dark matter ... (Score:5, Informative)

          by Tim C ( 15259 ) on Thursday November 24, 2005 @05:00AM (#14106711)
          The proposed solution to this is to assume that there must be extra unobserved (hence dark) mass providing extra gravitational energy, and thus extra orbital velocity, to the more outlying stars.

          Just to expand on this a little, as people may not know the physics behind this...

          The stars in question are gravitationally atrracted to the centre of the galaxy, just like the Earth is gravitationally atrracted to the Sun. Just like the Earth, they must either circle the gravitational source, or "fall" towards it. In order to remain in their orbit (rather than moving inwards or outwards) their centripetal acceleration must be equal to the acceleration they feel from the gravitational pull of the galaxy. (Centripetal acceleration is the acceleration required to keep them moving in a circle)

          If the gravitational pull is too strong, they'll be pulled in towards the galactic centre; if it's too weak, they'll fly off into space.

          Measuring their orbital speed allows us to calculate their centripetal acceleration, and thus the acceleration they feel due to the gravitational pull of the galaxy. This in turn allows us to calculate the mass that is producing the gravitational field that they are in:

          v**2/r = GM/r**2

          Where v**2 is the speed of the star, squared; r is the radius of the orbit of the star; G is the gravitational constant; and M is the mass of the galaxy producing the gravitational force.

          This gives us an estimate of the mass of the galaxy of rv**2/G.

          The problem is that working through the numbers gives us a mass that's significantly higher than we can account for from what we see. So, that leaves us with three choices:

          1) our understanding of dynamics is flawed (and so v**2/r is wrong)
          2) our understanding of gravity is flawed (and so GM/r**2 is wrong)
          3) there's stuff out there that we can't (currently) detect by other means

          1) would be pretty fundamental (that's some very basic physics indeed), as would 2). That only really leaves 3) as an attractive proposition (imho).
          • It is true that we can rule out 1).
            2) has a lot of momentum behind it but we cannot rule it out.
            3) is the easiest way out.

            Tully Fisher's relation (which is what MOND derives) makes
            3) not an easy way out for any scientist that compares MOND
            and Dark Matter.

            Dark Matter is ad-hoc. It is basically fitting the theories
            by assuming that something exists that we cannot see.

            Normally it would be a good choice, but MOND gives a simple
            equation which fits the curves of most galaxies without any
            extra parameters. The real
          • by aaribaud ( 585182 )
            I'll expand [...]
            Just to expand on this [...]
            Is it me, or do people seem to be increasingly expanding nowadays?
      • Re:Dark matter ... (Score:3, Interesting)

        by ttsalo ( 126195 )
        Now, if there was enough matter in the universe, the gravity between it would eventually slow it down, stop it, and finally start it contracting back together. That was a rather attractive idea -- that the big bang wasn't a one-time thing, but that we just happened to be seeing evidence of the most recent occurrence.

        The problem was that our estimates of how much matter there was in the universe came out well below what was needed for there to be enough gravity to make the expansion stop and eventually rev

      • Re:Dark matter ... (Score:5, Interesting)

        by OlsonSchmolson ( 896129 ) on Thursday November 24, 2005 @07:47AM (#14107032)
        I get tired of this description of the Big Bang as an explosion in the usual terms, as in things flying apart out into something, "matter flying off in all directions". It's popular science, and most people wouldn't know what the heck you were talking about if you described it any other way. But, it ought to be restated...

        It's an expansion of space, everything that is in space is just going along for the ride.

        A visual way to clarify that is to shoot down the idea people have that things cannot recede faster than light. That gets their attention, they all know about Einstein and c. Things cannot move through space faster than light, but space itself puts a distance between things that C can never outpace.
  • Still a blunder? (Score:5, Insightful)

    by Anonymous Coward on Thursday November 24, 2005 @01:13AM (#14106098)
    IIRC, Einstein "fudged" his equations (i.e., introduced the cosmological constant) to stop them from predicting that the universe would expand. Subsequently, Hubble discovered that the universe was expanding after all. Still later, it was found that the rate of expansion was not in line with Einstein's un-fudged equations. Since then, the value of the cosmological constant has really depended on what value you measure for the expansion of the universe.

    So, why is this news?
    • So, why is this news?

      That's what I thought. However a quick scan of the article suggests that the increase in the rate of expansion can be explained better by a Cosmological constant (which is a constant unlike Hubble's constant which is not) rather than the alternative Quintessence hypothesis where the repulsive force is not constant.

      So yes this story is new and possibly important.

    • Re:Still a blunder? (Score:3, Interesting)

      by EvanED ( 569694 )
      Yeah... and it may get worse. Here's the story to the best of my knowledge:

      Einstein did some calculations and stuff and came up with two potential models of the universe. (Perhaps two solutions to his equations?) One had the universe expanding, the other contracting. Einstein called up some astronomers and asked which it was. They told him to get lost, that the universe was static. So Einstein went back and added the cosmological constant so that it matched "reality." Later Hubble was like "look, y'all, the
      • by Anonymous Coward
        Einstein had an expanding model, but expansion normally slows down due to gravity. The "anti-gravity" cosmological constant counteracted that and produced a static universe that neither expanded nor contracted.

        Your argument about coincidence is basically correct; Einstein didn't have a "legitimate" reason to foresee the CC. Yet adding the CC is the simplest modification to his theory that you can make, so it's no surprise that Einstein hit upon the idea, even if he (and we) didn't know why that term ought
      • ... Later Hubble was like "look, y'all, the universe is expanding," and Einstein was like "my bad" ...

        Dude, lay off the grass! --- Didn't like Einstein totally die long before the Hubble was like, launched???

        Bummer man!
      • Everyone forgets to mention Hubble's 'associate', Humason.

        His work was what Hubble's Law is actually founded out, he and Hubble worked together, and he was the one that 'observed' the red shift.

        Sagan always took time to credit Humason, but very few other prominent people give him the recognition.
        • Everyone forgets to mention Hubble's 'associate', Humason. His work was what Hubble's Law is actually founded out, he and Hubble worked together, and he was the one that 'observed' the red shift.

          He's been dead for thirty years. Do you think he's still bitter?

  • Ohh yeah... (Score:5, Funny)

    by Elitist_Phoenix ( 808424 ) on Thursday November 24, 2005 @01:13AM (#14106102)
    If he's so smart how come he's dead?
  • by cffrost ( 885375 ) on Thursday November 24, 2005 @01:14AM (#14106110) Homepage
    Alright, Einstein's blunder is no longer his "comsmological constant"...

    His blunder has merely changed to the premature retraction of his "cosmological constant."
  • Imagine? (Score:4, Funny)

    by dorkygeek ( 898295 ) on Thursday November 24, 2005 @01:32AM (#14106179) Journal
    Imagine a Beowulf cluster of Einsteins.

  • by OpenGLFan ( 56206 ) on Thursday November 24, 2005 @01:43AM (#14106212) Homepage
    That just confirms the conspiracy theory that Einstein didn't actually come up with the Theory of Relativity himself, but was given it by aliens. I mean, c'mon, he was a patent clerk! That's like Bob from Accounting proving Fermat's Last Theorem.


    The aliens gave him the theory -- including the cosmological constant. Unfortunately, there wasn't actually a justification for it. Thinking quickly, Einstein ad-libbed that it without it, the universe would be expanding, "and, uhh, we all know that's not true, right, fellas?", sacrificing the chance to be the first one to "predict" this. He copied the answer from the back of the book and got busted for not showing all the work. C'mon, who hasn't that happened to?

    /With tongue firmly in cheek...

    • Obviously you haven't kept up with the decline in status of patent clerks as corporations and others are allowed by politicians to patent rotary motion facilitators. The only patent clerk I've known personally had a PhD and a law degree, and was definitely not Bob from Accounting. OK, I know that was meant to be a joke, but it's based on a fundamental misunderstanding. And, BTW, the dark matter in the post is Mrs. Einstein who did at least half of his best work. She still doesn't get enough credit, whereas
  • by ThndrShk2k ( 805287 ) on Thursday November 24, 2005 @01:52AM (#14106231) Homepage
    In later years, studies will show that Einstein actually CREATED the universe in some kind of unconcious blunder, giving him the "Genius" over the universal equations we praise today.

    What a fraud, and I would assume would be then, a god.
    • studies will show that Einstein actually CREATED the universe in some kind of unconcious blunder

      Don't tell that to the people who believe in Intelligent Design.
  • by Pedrito ( 94783 ) on Thursday November 24, 2005 @01:53AM (#14106238)
    dark matter anymore as per this past story. [slashdot.org]

    Granted, it's unproven at this point, but Occam's Razor and all, I vote for the theory that makes sense with matter and energy as-is and doesn't require some exotic matter/energy that exists only as speculation to fill an unknown.
    • Comment removed (Score:5, Informative)

      by account_deleted ( 4530225 ) on Thursday November 24, 2005 @02:29AM (#14106336)
      Comment removed based on user account deletion

    • I vote for the theory that makes sense with matter and energy as-is and doesn't require some exotic matter/energy that exists only as speculation to fill an unknown.


      And I think most scientists would agree with you. Of course you still have to come up with this theory you speak of that explains all observations without requiring exotic matter/energy that hasn't been directly observed.

      (psst... this story is about dark energy, not dark matter).

      The evidence for dark energy is that the expansion of the univers
  • by Goonie ( 8651 ) * <robert.merkel@b[ ... g ['ena' in gap]> on Thursday November 24, 2005 @02:01AM (#14106261) Homepage
    IIRC his biggest blunder was discounting quantum physics and spending the last half of his life trying to come up with an alternative model that didn't require the universe to be probabilistic.
    • by servognome ( 738846 ) on Thursday November 24, 2005 @02:43AM (#14106379)
      IIRC his biggest blunder was discounting quantum physics and spending the last half of his life trying to come up with an alternative model that didn't require the universe to be probabilistic.

      That's not a blunder, that's a difference of opinion.
    • Not exactly. Einstein was all over quantum physics and was one of the biggest contributors in the early days. You are right that he never accepted the probablistic aspects of quantum **MECHANICS**. In other words, he didn't like the math. There are a lot of people in the field who still agree with Einstein. i.e that probabilty is just a convenient way of predicting the outcome of quantum events, but does not reflect what is **REALLY** going on at the quantum level...
      • Yeah, that's reasonable, but the end result was that the last 30 years of his life he didn't contribute that much because he backed the wrong horse. Not that he was wrong to try an alternative approach, but it proved remarkably unproductive. If things had turned out differently and he had said "OK, I don't like QM, but let's see where the idea takes us", he might have made considerably more progress towards his ultimate goal of finding a more general theory that superceded it!
  • by whig ( 6869 ) on Thursday November 24, 2005 @02:13AM (#14106289) Homepage Journal
    Consider a spherical mass of uniform density. If an observer stands at the surface, the gravitational vectors sum to a unit vector from surface to center. If the observer stands at the center of the mass, the gravitational vectors sum to zero (all vectors cancel). If the observer stands at any location in between the first and second position, the gravitational vectors can be given as two sums, zero (canceled) for an equidistant radius from the observer's position to the surface and towards the center, and a distance vector from the observer's position and the residual (uncanceled) mass.

    The distance vector between the observer and the residual center of mass is constant at any point between the surface and the center of the mass. The residual mass decreases linearly as the observer descends towards the center. The gravitational force on the observer decreases linearly to zero over this domain. The radius of the sphere is the radius of maximum gravitation.

    Gravitational force may cause the radius of the sphere to contract. As the radius shrinks, it approaches the center of mass and therefore increases the gravitational force upon an observer standing at the radius as the inverse square of the change in radius until it relativistically approaches a point at which escape velocity equals the speed of light. To an external observer, the radius will seem to shrink more and more slowly until it seems to stop as it approaches this point. Likewise for the internal observer, but neither mass nor energy can now escape from inside the radius to the outside, so we cannot communicate with him unless we shift our perspective to his.

    Staying with our external perspective for the moment, however, we can measure the gravitational force at some distance from the radius, and observe how it acts upon other masses. Nearby matter may get swept into this gravity well, adding to the total mass of our system and increasing its externally determinable radius. But by appearing to slow down and stop at a radius greater than that of our original mass, it would not seem to reach the original radius at all.

    Now let's depart our external universe and try to figure out what's going on with our inside observer. First of all, he's not seeing any in-falling matter because his frame of reference is also much slower than that of the radius, in fact he'd have to wait infinitely long before anything like that would happen, so let's just say it doesn't. But that doesn't mean that he cannot observe any effects at all.

    What our man on the inside discovers is that there is intense energy, in the form of pressure, being applied to his little micro-universe. This pressure continues to build and build, charging our little spherical mass like a battery, until maximum energy density is reached. But the pressure continues, so the mass does what it has to do, it inflates.

    Our mass isn't just expanding in space; it is expanding "space." As pressure energy continues to pour in, the inflation continues until certain physical properties of matter and energy begin to assert themselves; and the inflation proceeds outwards and away from the original mass -- into the new universe.

    This is one possible explanation of how our universe may have begun. In searching for evidence of such a hypothesis, one might hope to find some sort of inflationary pressure which seems to operate against gravity. Since this "dark energy" seems probably, this may be a feasible cosmology.
    • Ah, the old "our universe is the inside of an event horizon that is located in another universe, which itself may be the inside of an event horizon that is located in another universe, ad nauseam" theory. That's been on my wouldn't-it-be-cool-if radar every since I had a layman's idea of what an event horizon was (i.e. not a rarely-rented DVD at the nearby Blockbuster). In your paper, did you go for the "event horizon formation == big bang in child universe" upgrade? Or even the "infinite hierarchy of un

  • The cosmological constant was a "hack". Einstein was right to retract it. I have always felt that Einstein's genius was his intuition and his ability to do "thought experiments" where he ran certain physical models until they contradicted common sense.

    But Einstein's intuition did him in and he was convinced the Universe was not expanding, so in comes the cosmological constant. It was the wrong reason to add it to his math models, despite subsequent evidence that some form of "fudge factor" may be needed to
  • I hate that problem !

    Isn't there a medical solution for these things?

    Do astronomers have more of these than the rest of us?
    Or do physicists and mathematicians also suffer from it?

    Gads, even Einstein had the problem.

  • Dark energy is the subtler form of dark matter. And even subtler is dark information - the stuff that nemory [uncyclopedia.org] is made of.
  • I thought dark energy was added to make our modern theories "work" to our expectations without knowing what dark energy was, and now it's told a concept that Einstein added to make his equations work to his expectations "sort of" matches (10% is still a big deviation) with this.

    So, since we know basically nothing either about what dark energy is or what the constant represent, are we sure that it's not both current researchers and Einstein that make a similar blunder?

    This would be oh so much easier if there

    • I thought dark energy was added to make our modern theories "work" to our expectations without knowing what dark energy was

      Pretty much, yah. To be fair though this is often a practice in science, to modify theory to meet new observation.

      and now it's told a concept that Einstein added to make his equations work to his expectations "sort of" matches (10% is still a big deviation) with this.

      Welcome to Cosmology! Where a 10% error is considered pretty good. This is probbably the biggest problem in Cosmology,
  • Um (Score:2, Interesting)

    by TallMatthew ( 919136 )
    The cosmological constant balanced out equations that assume a static universe. It wasn't based on anything observed; Einstein just knew he was missing something because he couldn't get his observations to follow his math.

    If you take a snapshot of the universe, if you discount its expansion, then the existence of dark energy, remnant of the big bang, is requisite to explain certain phenomena and balance out equations.

    Why is it weird these two are similar?

  • by n54 ( 807502 ) on Thursday November 24, 2005 @07:30AM (#14106997) Homepage Journal
    On topic:

    Fudge factor (Einstein) == fudge factor (dark energy/matter)

    What exactly is surprising about this? They were/are both added to represent something unknown, a pure speculation which is likely to fall (or be changed to the extreme) by Occams razor as science and knowledge progresses.

    http://www.astronomycafe.net/anthol/fudge.html [astronomycafe.net]

    Einstein retracted his fudge while still alive and I have a suspicion those championing dark matter/energy will have to as well :)

    Slightly off topic:

    Hmm was this the first valid and correct reference to Occams razor on Slashdot ever? Probably the first time here it wasn't used in a faulty manner applying it with anti-religious or ideological/political arguments (one would think people would get a clue from the fact that Occams razor was created by a Franciscan friar).

    religion != science
    Occams razor = intended for scientific theories (given two equally predictive theories, choose the simpler)
    Occams razor != rational to apply to religion

    *doesn't even need a flameretardant suit*
    • Hmm was this the first valid and correct reference to Occams razor on Slashdot ever?

      Probably not...

      Occams razor = intended for scientific theories (given two equally predictive theories, choose the simpler)

      Occam never formulated any principle like the modern "Occam's Razor," it was invented by later people. What Occam said was that you should not multiply entities unnecessarily, which does not mean that "a simpler theory" is better. At all. So, sure, Occam was religious , but Occam also did not use Occam's
    • Einstein retracted his fudge while still alive and I have a suspicion those championing dark matter/energy will have to as well :)

      Prior to the experimental (observational) discovery of the increasing rate of expansion of the observable universe (part of the multiverse ?) many physicists regarded the cosmological as essential to general relativity. Coleman for one asked the question why is the cosmological constant zero and proposed a hypothesis based on wormholes between universes to explain why it shoul

  • Stupid Question (Score:3, Interesting)

    by miyako ( 632510 ) <miyako AT gmail DOT com> on Thursday November 24, 2005 @12:43PM (#14107915) Homepage Journal
    I realize that this is probably a stupid question. I haven't had the math or physics yet to really understand probably all the reasons it's a stupid question, so I'll put it out there and see what people have to say on this (slightly) off-topic issue.
    Why is it not possible that the universe is simultaneously expanding and contracting?
    One question I've had for a while is, why couldn't the universe be shaped in such a way that the force causing accelleration on the expansion of the universe is actually the gravitational force of the universe contracting.
    To sort of illustrate my point, think of the game Asteroids. If you fly out of the top of the screen, you appear back on the bottom, and if you fly out the left side of the screen, you appear on the right side. Why couldn't there be some n-dimensional version of that concept in the universe such that as it expands it's actually approaching an earlier state?
    Anyway, if this is just the stupidist thing ever, please be kind in saying so. IAONAP (I Am Obviously Not A Physisist).
    • Re:Stupid Question (Score:3, Interesting)

      by bjorniac ( 836863 )
      Not a stupid question at all.

      It is possible to have the universe expand and contract in different directions at the same time. However, this isn't what we observe. Two of the basic ideas about the universe we assume to be broadly true (yes, not exactly but to a good approximation) are

      1) It is homogeneous. This is math speak for it's the same at every point
      2) It is isotropic. Math speak for looks the same in every direction.

      Now, this clearly isn't exactly true - if it were there would be no difference betwee

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