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Einstein's Biggest Blunder That Wasn't
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%."
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.. html
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http://super.colorado.edu/~michaele/Lambda/lambda
http://en.wikipedia.org/wiki/Cosmological_constan
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?
If he's so smart how come he's dead?
"I'm going to f***ing bury that guy, I have done it before, and I will do it again. I'm going to f***ing kill Google"
Scientists did not prove anything. Some merely published a theory. It is not in anyway proven. Science is not like engingeering where it either works or doesn't. The scientific process takes a while, and dark matter and dark energy are still a vital theory in explaining expansion of the universe. So please don't tell me Dark Energy doesn't matter, because if that's true, I'm wasting a lot of my time.
"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.
"It's overkill, of course. But you can never have too much overkill." - Anonymous Slashdot Coward
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.
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.
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.