Einstein’s Other Theory of Everything

Einstein finished his Masterwork the theory of general relativity in 1915 he was 37 years old and had live for another 40 years what did he do in those 40 years Einstein felt that his Masterwork was incomplete and he wanted to develop a unified faar theory indeed it was Einstein who coined the term he ultimately failed but that doesn't make his ideas any less interesting I think that Einstein had a very promising start but then took a wrong turn and recently I've begun to wonder whether anyone even still knows of his starting idea well if you watch this video at least you will know his idea was roughly this Einstein's general relativity says that gravity is a property of SpaceTime it's often depicted with a marble that weighs down a rubber sheet the rubber sheet is space time if a smaller marble Rolls by it'll not roll in a straight line it'll roll in a curve Earth as if it was attracted by the bigger marble but you still need that marble to cause the curvature in the first place it's the same in Einstein's general relativity you need both space time and matter in it Einstein seems to have try to find a theory in which there's only SpaceTime but we interpret some of that SpaceTime as matter he wanted to find equations that have solutions that correspond to the fundamental particles of nature I must admit that this is partly speculation based on what Einstein wrote in his papers but I'll explain in a moment why I think that's what he meant before I can do that however I have to tell you what the status of physics was at the time Einstein set out for his unified theory today physicists know four fundamental interactions besides gravity there electromagnetism and the strong and weak nuclear interaction but when Einstein finished his theory of general relativity the strong nuclear interaction had not yet been discovered and the theory for the weak nuclear interaction had not yet been developed so he really only had two interactions to work with gravity and electromagnetism these two are similar in that the gravitational force law which you can assign to a point Mass goes with 1 / R square just like the force law fourpoint charge and since Einstein had been so successful ful with describing gravity as the curvature of SpaceTime naturally he wondered whether electromagnetism could be described the same way in 1919 Einstein published a paper titled do gravitational fields play a role in the structure of Elementary particles the idea he pursued in the paper is to take a modified version of general relativity with different field equations then he added electromagnetism and asked whether this would give rise to solutions that could be interpreted temp as particles the conclusion he arrived at is that no this doesn't work because the quantity that could be interpreted as mass could take on any value whereas the particles that matter are made of have very specific values for the mass in 1923 then he published another paper titled does field Theory offer a solution to the quantum problem in this paper he basically says that his previous idea to make matter from SpaceTime didn't work because there are some equations missing he then guesses some equations that might do the job but again concludes that this doesn't work this video comes with a quiz that lets you check how much you remember in 1925 he publishes another paper in which he says that he's tried for two years to combine electromagnetism with gravity and it didn't work he presents a new idea in which he says that the metric tensor could have an anti-symmetric part part that might describe electromagnetism I know this is somewhat technical but in general relativity SpaceTime is described by a two tensor that's basically a glorified Matrix this Matrix is symmetric meaning that the entries above the diagonal are the same as those Below in electromagnetism you have instead something called the field strength tensor which is anti- symmetric that means the entries above the diagonal are the same as those below multiplied by minus one the thing is now that if you have an arbitrary two tensor you can take that apart into a symmetric and an anti-symmetric part so Einstein said we'll make the metric tensor into an arbitrary tensor use the symmetric part for gravity and the anti-symmetric part for electromagnetism I think that this is where things went wrong because the magic tensor in general relativity is not related to the field strength tensor but to the electromagnetic potential if you wanted to combine the two you'd have to put the electromagnetic potential into the metric and this is indeed what Hodor Kusa did he added a fourth dimension of space and put the electromagnetic potential there the idea would later be refined by Otto Klein and is now known as Kusa Klein Theory and this idea Works indeed beautifully it gives you both general relativity plus Max equations for electromagnetic fields from the same mathematics baloa Klein Theory only gives you the electromagnetic fields it does not give you charged particles so it didn't solve the problem that Einstein wanted to solve it didn't make matter out of SpaceTime maybe this is why he didn't adopt the idea but Einstein had another clue for his unified theory and that was black holes yes black holes you see as soon as Einstein had finished his theory of general relativity Carl schwartzel discovered a solution to Einstein's equations that described what we now call black holes but this solution has singularities places where some quantities take on infinite values Einstein thought that this can't be right singularities shouldn't happen in reality and if his theory allowed those that there was something wrong with it he therefore tried to use the requirement that singularity should be absent to find these solutions that describe Elementary particles but he made a mistake there in Schwartz's black hole solution there isn't just one Singularity but two one is at the Horizon of the black hole the other one in the center we know today that the singularity at the Horizon does not correspond to any physically measurable quantity it's a mathematical artifact that can be removed Einstein tried to find a way to remove these singular which wasn't there in the first place you'd think that physicists would have learned from this that it's a mistake to go on about the properties of unobservable quantities but it's the same mistake that led to all these wrong predictions for the large hron collider but ey digress back to Einstein that Einstein wanted to get rid of black hole singularities is what led to his famous paper with Nathan Rosen in 1935 in which they introduced used what's now called an Einstein rosenbridge what they did was to take away the inside of the black hole and instead connect two universes it's the simplest known example of a wormhole but they didn't write the paper to introduce wormholes oh no Einstein and Rosen thought these wormholes were Elementary particles after they've constructed their bridge in the paper they write very clearly we see now in the given solution free from singularities the mathematical description of an elementary particle neutrons or neutrinos they then go on to add electric charges and interpret that as charged particles now one thing you may have noticed is that we know today that neutrons are not Elementary particles but this wasn't the main problem with the idea the main problem is that one can calculate the size of the bridge or Wormhole or whatever you want to call it from its mass and that'll tell you that the size of a neutron would be about 10 to Theus 52 CM that's more than 30 orders of magnitude smaller than its actual size for other Elementary particles this becomes even more extreme this means that if Elementary particles were wormholes or black holes they'd be much smaller than the quantum uncertainty that we measure Steven Hawking also taught us that they'd be unstable but again Einstein couldn't have known this in any case Einstein didn't pursue this idea further instead he pursued his early idea from 1928 of putting electromagnetism into the metric tensor the idea that he introduced is that of telip parallelism and it's what's later become known as Einstein's unified theory in the following 10 years he published 10 or so papers about this in a nutshell Einstein's unified field theory is a modified version of general relativity that has more equations the these additional equations Einstein said would represent electromagnetism it's called T parallelism because it first does away with the curvature of SpaceTime but then requires that coordinate frames in different places so telly are parallel to each other that's why Telly parallelism from today's perspective it's obvious why this couldn't work for one thing we know that electromagnetic fields have Quantum properties and you wouldn't get the right maths out of this teley parallelism because it's not a quantum theory Einstein probably knew this but ignored it because he didn't believe that quantum theory was fundamentally correct Einstein's unified theory also doesn't contain the weak and strong nuclear force there just aren't sufficiently many equations for that but again he couldn't have known this and finally in 1928 the same same year that Einstein laid out the idea durak understood that all particles of matter have spin one half and they need special equations that you couldn't get out of Einstein's Approach at all this by the way is also why cloa Klein Theory ultimately doesn't work because of the spin one half fields to make that work you need to introduce super symmetry but that's another story these are the major reasons why unified field theory was not not pursued after Einstein's death because by then it had become clear that it wasn't compatible with the new things that physicists had discovered that said I find it somewhat surprising and maybe even concerning that physicists have also thrown out Einstein's original idea that I want to call his other Theory of Everything the idea that matter is really just made of SpaceTime curved in a particular way this notion has survived in some areas of physics where such objects are known as solons or noise-free subsystems but mostly it's been given up it's been replaced by a different idea of unification that matter and SpaceTime are both made of something else like for example strings or Loops or networks or what have you so why am I telling you this primarily because I think it's interesting what Einstein one of the undoubtedly most intelligent people to ever walk on this planet did with his life but also because I don't want Einstein's idea to be forgotten if this video inspired you to develop your own unified theory there's no better place to start than brilliant.org yes you've heard me talk about brilliant before but have you ever given it a try I think you really like it they have courses on a large variety of topics in science Computer Science and Mathematics and they're adding new ones each month I have found it to to be a simple and effective way of learning something new all their courses have interactive visualizations that are super helpful to understand what's going on and they all have follow-up questions so you know that helps me to make sure I don't just gloss over something and click on next I even have my own course on brilliant that's an introduction to my favorite topic quantum mechanics I had a lot of fun working on this together with brilliant's team and I hope you'll enjoy it too to give it a try use our link brilliant.org szabina that will give you access to everything on brilliant for 30 days and 20% off an annual premium subscription thanks for watching see you tomorrow

Channel: Sabine Hossenfelder

Views: 358,494

Keywords: science without the gobbledygoook, hossenfelder, einstein, physics, theory of general relativity, theory of everything, gravity, quantum gravity, quantum physics, quantum, fundamental interactions, elementary particles, standard model, electromagnetism, black hole, unified field theory, Einstein's unified theory, Einstein's theory of everything, are particles black holes, black holes, wormholes, are wormholes particles, ER bridge, einstein rosen bridge, Albert Einstein

Id: MfIY2vf7c04

Length: 13min 19sec (799 seconds)

Published: Sat May 18 2024