David Levy Posted May 5, 2017 Posted May 5, 2017 I would like to understand the history of the cosmological constant. In the following article it is state: https://en.wikipedia.org/wiki/Static_universe "Albert Einstein added a positive cosmological constant to his equations of general relativity to counteract the attractive effects of gravity on ordinary matter, which would otherwise cause a spatially finite universe to either collapse or expand forever". However, it is also stated: https://en.wikipedia.org/wiki/Cosmological_constant "Einstein later reputedly referred to his failure to accept the validation of his equations—when they had predicted the expansion of the universe in theory, before it was demonstrated in observation of the cosmological red shift—as the "biggest blunder" of his life. Questions: 1. Why Einstein had considered the cosmological constant as the biggest mistake of his life? 2. Why he didn't eliminate the cosmological constant from his equations of general relativity after understanding his big mistake? .
Mordred Posted May 5, 2017 Posted May 5, 2017 Einstein originally used the cosmological constant to make the universe static. His original model without it predicted a contracting or expanding universe. He originally didn't like that so attempted to make his equations lead to a static solution. That was his blunder.
David Levy Posted May 5, 2017 Author Posted May 5, 2017 Thanks Einstein originally used the cosmological constant to make the universe static. His original model without it predicted a contracting or expanding universe. That is clear. He originally didn't like that so attempted to make his equations lead to a static solution.That was his blunder. What do you mean by static solution? Is it the expansion theory?
Mordred Posted May 5, 2017 Posted May 5, 2017 (edited) static universe (eternal) the belief of the time was an eternal universe not expanding or contracting. That discovery came out later via Hubble prior to Hubble's discovery Einstein used the cosmological constant to model a static eternal universe. (ps before the typical next question. No big bang in an eternal static universe.) Edited May 5, 2017 by Mordred
Strange Posted May 5, 2017 Posted May 5, 2017 What do you mean by static solution? Is it the expansion theory? Quite the reverse. Static = unchanging (not expanding).
David Levy Posted May 5, 2017 Author Posted May 5, 2017 O.K. Einstein originally used the cosmological constant to make the universe static. However, when he had understood that the Universe isn't static (as he had considered), he claimed that it was a big mistake to add the cosmological constant to his equations of general relativity If that is correct: 1. Why he didn't eliminate the cosmological constant from his equation? (If it is a mistake - than please fix it. It was his equation. I would assume that Einstein had to eliminate errors from his equation) 2. Why he didn't say that his theory for universe static was a severe mistake. Why he only focus on cosmological constant?
Mordred Posted May 5, 2017 Posted May 5, 2017 (edited) Yes the first part is correct. The cosmological constant did drop from the equations for a time. However when we discovered the acceleration due to aka dark energy the cosmological constant was reintroduced however its purpose is not identical. Ie its now used to account for the added expansion rate. Side note some older textbooks have the FLRW metric without Lamnda those equations were later fixed in newer textbooks. (This happens to be one example where equations have been upgraded from its origin ) Edited May 5, 2017 by Mordred
David Levy Posted May 5, 2017 Author Posted May 5, 2017 (edited) Yes the first part is correct. The cosmological constant did drop from the equations for a time. However when we discovered the acceleration due to aka dark energy the cosmological constant was reintroduced however its purpose is not identical. Ie its now used to account for the added expansion rate. Side note some older textbooks have the FLRW metric without Lamnda those equations were later fixed in newer textbooks. (This happens to be one example where equations have been upgraded from its origin ) If Einstein had eliminated the cosmological constant from his equation then it must be final. Hence, the cosmological constant must be out of Einstein equation for ever. Could it be that by adding someting to this equation (even if we call it also "cosmological constant"), then it is a sever violation of Einstein equation? Edited May 5, 2017 by David Levy -1
Mordred Posted May 5, 2017 Posted May 5, 2017 (edited) Why would you think that? No physicist is ever the final authority. No equation is set in stone. Theories and models are adaptive hence the sheer power of mathematics. We still call it the Einstein field equations as he is acreddited with the original work. This does not mean we throw out the entire work simply because we had to adapt it or ignore the contributions of the original. Edited May 5, 2017 by Mordred
Strange Posted May 5, 2017 Posted May 5, 2017 1. Why he didn't eliminate the cosmological constant from his equation? (If it is a mistake - than please fix it. It was his equation. I would assume that Einstein had to eliminate errors from his equation) 2. Why he didn't say that his theory for universe static was a severe mistake. Why he only focus on cosmological constant? 1. He did. Why do you think he didn't? 2. What's the difference? Adding the constant because he thought the universe was static, was the mistake. Meaning that he could have been more imaginative / braver and predicted the expanding universe before anyone else. If Einstein had eliminated the cosmological constant from his equation then it must be final. Hence, the cosmological constant must be out of Einstein equation for ever. Could it be that by adding someting to this equation (even if we call it also "cosmological constant"), then it is a sever violation of Einstein equation? If the equation can be updated once based on new information then it can be updated again, when there is more new data.
Mordred Posted May 5, 2017 Posted May 5, 2017 Lol I find this kind of amusing. I lost count how many times I have seen you post " We should update our equations" in other posts by you. I thought you would be happy seeing an example where we have done just that. Sorry couldn't resist Still laughing 2
David Levy Posted May 5, 2017 Author Posted May 5, 2017 (edited) Why would you think that? No physicist is ever the final authority. No equation is set in stone. Theories and models are adaptive hence the sheer power of mathematics. We still call it the Einstein field equations as he is acreddited with the original work. This does not mean we throw out the entire work simply because we had to adapt it or ignore the contributions of the original. We must respect and accept Einstein will. As Einstein said - no, than it is no. There is no room for - but... He had clearly enounced that the cosmological constant is his biggest mistake and therefore we had been forced to eliminate this constant from his equation Hence, it is forbidden to add it back against his clearly request and under any circumstances. Once we add it back - this is a severe violation of his request and his equation. With that cosmological constant - we can't call it Einstein equation any more. It is forbidden!!! We are using the Glory of the name "Einstein" for an updated equation which is absolutely unacceptable by Einstein himself. Sorry - but this is a severe violation that the modern science is doing under big "Einstein" name. If I understand it correctly, we are using this constant in order to prove the expansion. If that is correct, then we have to find different equation or some other way to prove the expansion! We shouldn't use Einstein equation against his clear request and will. Edited May 5, 2017 by David Levy -4
Strange Posted May 5, 2017 Posted May 5, 2017 If I understand it correctly, we are using this constant in order to prove the expansion. You don't and we aren't. 2
Mordred Posted May 5, 2017 Posted May 5, 2017 (edited) There is no patent for an equation...The given name for an equation is strictly honorary Edited May 5, 2017 by Mordred
Lord Antares Posted May 5, 2017 Posted May 5, 2017 There is no patent for an equation...The given name for an equation is strictly honorary In other words, the correctness and usefulness of the theory is what decides if it will be used, not the general esteem of the author. To suggest otherwise would be an argument from authority fallacy.
David Levy Posted May 6, 2017 Author Posted May 6, 2017 Sorry - If I was too direct. But, I have asked myself: How Einstein would feel or tell us if he could come back to life and see that we are using the cosmological constant against his clear will. -2
David Levy Posted May 6, 2017 Author Posted May 6, 2017 Why does it matter what he would think? Well, please see the following and decide by yourself: https://en.wikipedia.org/wiki/Albert_Einstein Albert Einstein was a German-born theoretical physicist. He developed the theory of relativity, one of the two pillars of modern physics (alongside quantum mechanics).[1][5]:274 Einstein's work is also known for its influence on the philosophy of science.[6][7] Einstein is best known in popular culture for his mass–energy equivalence formula E = mc2 (which has been dubbed "the world's most famous equation").[8] He received the 1921 Nobel Prize in Physics "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect",[9] a pivotal step in the evolution of quantum theory. Einstein thought that Newtonian mechanics was no longer enough to reconcile the laws of classical mechanics with the laws of the electromagnetic field. This led him to develop his special theory of relativity Known for General relativity and special relativity Photoelectric effect E=mc2 Theory of Brownian motion Einstein field equations Bose–Einstein statistics Bose–Einstein condensate Gravitational wave Cosmological constant Unified field theory EPR paradox Influenced Ernst G. Straus Nathan Rosen Leó Szilárd Notable awards Barnard Medal (1920) Nobel Prize in Physics (1921) Matteucci Medal (1921) ForMemRS (1921)[1] Copley Medal (1925)[1] Gold Medal of the Royal Astronomical Society (1926) Max Planck Medal (1929) Time Person of the Century (1999) 1
Mordred Posted May 6, 2017 Posted May 6, 2017 (edited) Ya know I'm gonna award a +1 on your research into Einsteins credentials. Excellent research. Still doesn't change the detail Einstein was probably more than aware the cosmological constant was problematic. Personally I feel that he would be truly proud that his contributions to those links and is of fundamental importance in all of them. Even to this day despite the cosmological constant his works are of immense importance. He probably would never would have expected his works to so robust. (personal opinion) In other words, the correctness and usefulness of the theory is what decides if it will be used, not the general esteem of the author. To suggest otherwise would be an argument from authority fallacy. Precisely Edited May 6, 2017 by Mordred
David Levy Posted May 6, 2017 Author Posted May 6, 2017 (edited) Sorry, It seems that I didn't explain myself correctly. No equation is set in stone.Theories and models are adaptive hence the sheer power of mathematics. We still call it the Einstein field equations as he is acreddited with the original work.This does not mean we throw out the entire work simply because we had to adapt it or ignore the contributions of the original. I fully agree with you that theories and models are adaptive. We can change and update the equation. Still doesn't change the detail Einstein was probably more than aware the cosmological constant was problematic.Personally I feel that he would be truly proud that his contributions to those links and is of fundamental importance in all of them. Even to this day despite the cosmological constant his works are of immense importance.He probably would never would have expected his works to so robust. (personal opinion)Precisely Einstein is considered as the father of the modern science. If we get a command from a father then we must respect it. Einstein told us clearly that we shouldn't use the cosmological constant in his equation. Therefore, we shouldn't use it. If we use it, it isn't adaptation. It is violation. However, if we think that we must add a constant to the equation, then at least we shouldn't call it cosmological constant. We should find new name for this constant and prove our new adaptive equation. We will give it a new name as it is no longer belonging to Einstein. If needed, we will also give a Nobel Prize for the scientist which is able to prove the validity of the equation with new name for the cosmological constant. Never the less, it is forbidden to take Einstein equation as is, add the cosmologic constant (which Einstein told us not to use) and then say - yes, this is Einstein equation. I still believe that it is a sever violation of Einstein will. In any case Why is this cosmological constant so important for us? Edited May 6, 2017 by David Levy
Mordred Posted May 6, 2017 Posted May 6, 2017 Science isn't a religion. Perhaps your not explaining yourself well again? There is no patent ob a formula. Einstein knew this before he published.
Strange Posted May 6, 2017 Posted May 6, 2017 Sorry - If I was too direct. But, I have asked myself: How Einstein would feel or tell us if he could come back to life and see that we are using the cosmological constant against his clear will. As it matches the evidence he would do the same. Einstein is considered as the father of the modern science. If we get a command from a father then we must respect it. Ha ha ha ha. Seriously, that is not how science works. It advances by overthrowing the "fathers". If needed, we will also give a Nobel Prize for the scientist which is able to prove the validity of the equation with new name for the cosmological constant. The discoverers did get Nobel Prizes. In any case Why is this cosmological constant so important for us? Because it matches what we observe (the same reason it was set to zero previously).
David Levy Posted May 6, 2017 Author Posted May 6, 2017 (edited) As it matches the evidence he would do the same. Because it matches what we observe (the same reason it was set to zero previously). O.K. Let's see if I understand it correctly: We have developed the BBT theory based on our observation. This theory includes several sections including the expansion, inflation and others. In order to support those theories and hypothesis we had to go back to Einstein equation and add that forbidden Cosmological constant. In other words, we need the cosmological constant to support our updated theories about the Universe. Now, if someone will dare to come and say that there is a simple explanation for what we see, we will tell him that our theories had been proved by Einstein equation. As no one can argue with Einstein - then no one can argue with our current theories. Win win solution Did I understand it correctly? Edited May 6, 2017 by David Levy
Klaynos Posted May 6, 2017 Posted May 6, 2017 Did I understand it correctly? No. If someone came along with a mathematical theory as robust as our current theory but more accurately agreed with the observations (taking error analysis into account) then we would start using the new theory. What you have to bear in mind is that BBT and general relativity are incredibly accurate in the domains of applicability. So a simple first test as to whether a new theory is valid is whether it gives the same numerical predictions as them. Interestingly this can be done for general relativity. Where Newtonian gravity works GR must produce the same result else we'd have known quickly that it was not going to work. 3
Strange Posted May 6, 2017 Posted May 6, 2017 Theories are never proven. And certainly not by equations. They can only be confirmed or disproved by evidence. So if it was found that expansion is not accelerating (the observations were mistaken, an alternative explanation is found, or ...) then the constant would be set back to zero.
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