Oh squiggly line in my eye fluid. I see you lurking there on the periphery of my vision. But when I try to look at you, you scurry away. Are you shy, squiggly line? Why only when I ignore you, do you return to the center of my eye? Oh, squiggly line, it’s alright, you are forgiven.
@@Sammusg WHY ELECTROMAGNETISM/ENERGY IS UNIFIED AND BALANCED WITH/AS WHAT IS GRAVITY: Gravity AND ELECTROMAGNETISM/ENERGY are LINKED AND BALANCED opposites, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Therefore, Einstein's equations and Maxwell's equations are unified (given the addition of a fourth spatial dimension); AS E=mc2 is DIRECTLY and fundamentally derived from F=ma; AS TIME DILATION proves that electromagnetism/ENERGY IS GRAVITY. ACCORDINGLY, Einstein's equations predict that SPACE is expanding OR contracting in and with TIME; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. GREAT !!! (Very importantly, outer "space" involves full inertia; AND it is fully invisible AND black.) Gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Accordingly, the rotation of the Moon MATCHES it's revolution. "Mass"/ENERGY involves BALANCED inertia/INERTIAL RESISTANCE consistent WITH/as what is BALANCED electromagnetic/gravitational force/ENERGY, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Accordingly, objects fall at the SAME RATE (neglecting air resistance, of course); AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Gravity IS ELECTROMAGNETISM/ENERGY. A PHOTON may be placed at the center of what is THE SUN (as A POINT, of course), AS the reduction of SPACE is offset by (or BALANCED with) the speed of light; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Energy has/involves GRAVITY, AND ENERGY has/involves inertia/INERTIAL RESISTANCE. THE SUN purely exemplifies time DILATION. INSTANTANEITY is FUNDAMENTAL. Time DILATION proves that electromagnetism/ENERGY IS GRAVITY, AS E=mc2 is DIRECTLY and fundamentally derived from F=ma. "Mass"/ENERGY IS GRAVITY. ELECTROMAGNETISM/ENERGY IS GRAVITY. Gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. GREAT !!! The stars AND PLANETS are POINTS in the night sky. Let's compare this directly with BOTH a falling object AND the speed of light (c). Great. E=mc2 IS F=ma. Gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. GRAVITATIONAL force/ENERGY IS proportional to (or BALANCED with/as) inertia/INERTIAL RESISTANCE, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Gravity IS ELECTROMAGNETISM/ENERGY. This NECESSARILY represents, INVOLVES, AND describes what is possible/potential AND actual IN BALANCE. Time DILATION proves that electromagnetism/ENERGY IS GRAVITY, AS E=mc2 is DIRECTLY and fundamentally derived from F=ma. INSTANTANEITY is FUNDAMENTAL to the FULL and proper understanding of physics/physical experience. Ultimately and truly, TIME is possible/potential AND actual IN BALANCE; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. The ultimate unification of physics/physical experience combines, BALANCES, AND includes opposites, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. GREAT. It ALL makes perfect sense. THINK !!! The Earth that undergoes time DILATION IS thus represented (ON BALANCE) as what is A POINT in the night sky, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. (So, notice that the BLUE SKY IS no longer visible. Think.) E=mc2 IS F=ma. It is FULLY proven. Gravity IS ELECTROMAGNETISM/ENERGY. ELECTROMAGNETISM/ENERGY IS GRAVITY. Alas, the INTEGRATED EXTENSIVENESS of THOUGHT (AND description) is improved in the truly superior mind. I have truly, CLEARLY, AND MATHEMATICALLY unified physics/physical experience. OVERLAY what is THE EYE in BALANCED RELATION to/WITH what is THE EARTH. (Notice the black space of THE EYE, AND the DOME of a person's eye is ALSO visible.) THE EARTH is ALSO blue. Again, E=mc2 IS F=ma. The stars AND PLANETS are POINTS in the night sky. Time dilation proves that E=mc2 is DIRECTLY and fundamentally derived from F=ma, AS electromagnetism/ENERGY IS GRAVITY. It ALL makes perfect sense. Gravity IS ELECTROMAGNETISM/ENERGY. ELECTROMAGNETISM/ENERGY IS GRAVITY. BALANCE AND completeness go hand in hand. By Frank DiMeglio
H. Sch. Which is fine, nay sayers and experimentalists can also lead to progress or at least sift out false theories. Never understood why people act so condescending about them.
You wanted to say: "no real case except its predictions that match low-energy as well as high-energy experiments, and some predictions that exceed the energy levels we can experiment with today, but would constitute a strong case for or against string theory if we ever go that far; oh, and being the only workable theory of quantum gravity in existence"
@@hasch5756 String theory touches on many branches of mathematics which are described as quite beautiful. String theory itself is quite UGLY. As "mathematics" it resembled a big giant ugly hairball. I know what beautiful mathematics IS and I know how to do these string theory calculations. These calculations are rote, tedious, boring, unenlightening. String theory as it exists right now is NOT an elegant theory. Far from it.
Great video! Please, more of these lengthy interviews :) Showing the natural progression of theories really help a great deal in understanding (to my limited extent) this material.
the problem I keep encountering with arguments for string theory is that they usually boil down to "the maths is nice". It would be nice to maybe get a video on the case for an alternative theory as well, just for variety.
I'd like to see something that explains "what experiment could we do that would differentiate between the Standard Model and String theory?". ie, if Standard and String can't both be right, how can we prove one wrong?
@@johnblankenhorn9730 someone tell me if I'm wrong but I don't think string theory debunks the Standard Model at all... its more like a level below the standard model.. I'm pretty sure the ultimate complete string theory model would/should encompass the the standard model, which is build based on quantum mechanics or quantum field theory.... and then also should reproduce General Relativity.. Infact if It didn't reproduce some or most aspects of those models it would be a sure fire sign that string theory is COMPLETELY wrong... that is the point of a "THEORY OF EVERYTHING after all...
remember for the maths of a physics system to "be nice" it also has to accurate describe the system it's describing, which string theory does, apparently
Haha! Well, I meant Brady. Obviously for the actual speaker, someone from the "other camp" would be needed to make an equally enlightening and passionate case for the correct theory as you did for the sadly misguided one ;þ
I feel like you should have at least mentioned it, instead of saying there are no other alternatives to String Theory. Also, to me background dependece is very much a problem of st that you should have talked about. Still, a nice video, really hope they're gonna get Rovelli to talk about LQG next. Have a nice day!
"instead of saying there are no other alternatives to String Theory" What? He literally says "What is the correct theory of quantum gravity? Is it string theory or is it one of the suggested alternatives?"
I'm sorry, I watched the video again, and I mixed up the parts of the videos where he's talking about alternatives for quantum gravity and solutions to putting together qm and sr. I still think he should have mentioned LQG. Have a nice evening. p.s. (that's what happens when you comment online while being too tired and sleepy, my bad)
1:30 no no No NO! Damn it. Aristotle did not come up with atoms. In fact, he was OPENLY AGAINST the idea of atoms (brought up by other ancient Greeks like leucippus and Democritus). Aristotle was wrong about almost EVERYTHING relating to science. I just don't understand why people always think of him as some scientific genius and always falsely give him credit for stuff.
If you want a really in depth critique of Super String theory, I suggest you read Peter Woit's book Not Even Wrong. Its a great review of the mathematics and history of ST. The math references can be a bit challenging, but it is well worth the effort for the serious student. The book ends with an overview of how ST became so entrenched in academia that it became self-sustaining in spite of St's utter failure to even meet the orthodox criteria as a scientific 'theory'. I loved Richard Feynman's comment that "String theorists do not make predictions. They make excuses!".
There's a great book by the name of 'The Elegant Universe' by Brian Greene, that goes into a great deal of depth about Special/General Relativity, Quantum Mechanics, and string theory. It describes things in varying levels of complexity with some really great metaphors/analogies that are easy to understand. The book is a bit old and he's probably got more modern books with more contemporary emphasis, but I haven't read em.
His paper suffers from many weak arguments. It has been debunked in several professional papers already and it has been shown in several publications how the predictions his theory makes deviates severely from measurements already made. Look up Sabine Hossenfelder's blog for more information.
I've seen a conference in Brussels with Verlinde, and I must say, yes, emergent gravity is pretty interesting and exotic, but has many problems. At some moments, Verlinde himself looked uncomfortable with his own theory.
As I understand it, the trouble with String Theory is that in it, there can be several different "models" of the Universe, only one of which can be a model of the Universe we actually live in. Now, each "model of String Theory", if you will, gives different predictions about the results of experiments. The trouble is this: we don't know which model of the Universe is our Universe, so if we'd even do an experiment that contradicts a model of String Theory, we could just say: _"Oh, so it isn't that model, then"_ and switch to another -- effectively making it impossible to fully disprove String Theory, which makes it more of an "excuse generator" (by lack of a better term) than a rigorous Scientific Theory.
Great Video Tony. Just like Maxwell, Einstein, Dirac and Higgs it shows how a mathematical exploration of current knowledge can suggest new things to look for, and where and how to look for them.
From my time at the university (the other members of our work group were mostly into loop quantum gravity) i remember the biggest complaint about string theory was never from the quantum side of particle interactions, but that it totally failed to provide a background independend generalization of general relativity and in fact even seemed to make it harder to construct such a mechanism. It picked my interest, that you not even tangentially addressed this problem, when every thing that needs a quantum description of gravity at very high energies (black hole interiors, or the pre inflationary universe for example) need an actual description for the energy momentum tensor, or a framework to replace the field equations currently used to map general relativity. Especially as a cosmologist, shouldn't those issues be also the nail you are hanging on, or has there been a major development that i missed, filling this significant void in the theory?
finally a good explanation of reasons that led to string theory for the general public, not the usual "hmmm, what if everything is made out of strings?" story
I would be interested in how you make a case for gravitons since, by Einstein's Physics, gravity is the curvature of space-time. Therefore gravity is not actually a force, not in the sense that the strong or weak force is. So, there is no need for a 'graviton'. Please explain!
This is very nice Dr. Brady and Dr. Padilla. I'm looking on options for my masters and I'm exploring through some branches of physics out there. I'm divided between normal Astronomy / Planetary Science and Nuclear Cosmology / Particles. This was a very beautiful way to present string theory and other common subjects in Particle Physics, which gives it some nice points. Thanks.
Honestly string theory has always seemed to me (someone who is not a theoretical physicist) to be a very complicated and somewhat beautiful way to say absolutely nothing at all about how the universe works. If you can't test it or apply it, does it really mean anything at all? My impression from the outside that it's not applicable or testable might be completely wrong though. If it is, I'd love to see a video about potential applications or experiments in string theory.
I'm not a physicist but i am a scientist. A theory that produces a whole landscape of models, which can be retrofitted to any experimental result is not predictive. I'm not saying it's wrong, but until they come up with a single model that predicts experimental results that we can check, it's not science but an excercise in maths, no matter how elegant the physicists find it.
I love the ending to this video it's so amazing. "Well some people criticize it because it predicts 10 spacetime dimensions. This isn't really an issue I mean the extra 6 could easily be wrapped up real small or something so don't worry about that." (paraphrasing obviously)
Here are a couple of things that trump has said about String Theory: "We will have so much String theory if I get elected that you may get tired of String Theory, believe me. And you will say: please, its too much String Theory, Mr. president we can't take String Theory anymore, its too much. And I will say: No it isn't, we have to keep String Theory, we need to have more String Theory, we are going to have so much String Theory. Love you all, get out and vote!!" "Mexico said they where not going to have any String Theory. My reply: The strings just got ten feet longer"
An hypothesis that has been tested but could not be refused, becomes a theory. Any theory is just a hypothesis that has not yet been disproven, despite trying.
liquidminds Not really the case. String theory is not a Scientific theory. Even by what you were saying, it hasn't been tested. it's a mathematical proof. It is nothing like a theory.
mathematical theories still undergo testing. The type of proof just looks different. It being mathematically proven, does not mean that it is proven to be valid in our reality though. That is an important distinction, I give you that.
@liquidminds That's not how that works. A theory is a description of the *why* of a process, the mechanics, the guts, the nuts and bolts. It is supported by hypotheses, which are if-then testable guesses. The theory comes in with the implication from those hypotheses. If your notion of hypothesis->theory is true, then what hypothesis is the theory of gravity? Though not mentioned here but worth talking about, a law is just an observation which appears to be consistent. Law of gravity is "there always is a pull in this direction and it behaves like...". Theory of gravity is "there is a pull in this direction because...".
ok ok , so it is just a theory then :D j/k i don't know how well tested it is, but would have assumed, if it is a theory, there would be no alternatives to it.
No, the diagram in the video is correct, it's a scattering process. The diagram I assume you are thinking of is an interaction process which would have a vertex as they join, producing a photon, which then splits back into an electron and a positron at another vertex.
These videos keep my motivated to a career in physics. Seeing scientists talking about these cutting edge fields. Because sometimes it can be hard to maintain that inspiration in such a world and culture as we have.
I'd really like to see some videos on photonics/light. most of our technology is based on manipulating electrons, what interesting things may come from learning how to manipulate light the way we do with electricity.
I like your videos, I'm studying physics at the undergraduate level and it's really nice to get information that's easy to process and closer to the big picture than the minutiae every once in a while
I love the last few seconds where he quickly mumbles something about 6 'missing' dimensions that aren't really a problem. I love it when people try to minimize things that don't fit what they choose to believe.
It is. The great 11 dimensional unifying M-theory does not even exist. It is just a dream, like a proof of the Riemann hypothesis, right now there are 5 kinds of string theories in 10d that are separate.
empCarnivore string theory is an unfortunately name because string theory isn’t an actual scientific theory, it’s a theory in the sense of mathematics. (Number theory, group theory, set theory) these things are not “proven” they are just a branch of mathematics.
the thing i don't understand about string theory is what the strings actually are. what is the fundamental nature of a string? what is it made of? what is it's mode of existience? what does the vibration of the string look like on it's own scale?
You can think of particles like oscillations in their wave medium (higgs field, electromagnetic field, gravity field, etc). These oscillations interact with other oscillations in ways which we model using quantum field theory (QFT). These interactions cascade through the wave medium, causing new interactions at the locations of new interactions that propagate down the line. Now what happens if this propagation line meets where it started and it starts propagating down space it's already been? You get what's called a standing wave. A standing wave is any time where a wave goes back on itself within a given space. Usually this is done by bouncing against a barrier of sorts and is most spectacularly observed with sand on a vibrating plate. At all frequencies of oscillation of the plate, there is a standing wave, but at certain oscillations based on the shape and material properties of the plate, the waves will line up and you get the special case of standing waves that everyone thinks about when talking about standing waves: the lines of sand in pretty shapes. There's a sixty symbols video on this topic. Why am I talking about this? Because the same thing happens at the lower scales, the scales of particles. There is an oscillation in the quantum field which creates a standing wave (special case with lines, here) and this standing wave is relatively stable and will continue to oscillate until it decays internally (is such a thing actually possible in string theory? I'm just guessing when I say it'll decay) or is affected by its environment and loses its stability, until it reaches a new stable oscillation: the result of the particle interactions, or to use chemistry terms: the result molecule. So to call it a string is more a description of the shape of the energy. It moves and bounces around according to QFT (or more accurately, the reality-process we model with QFT), but "it" is just a stable energy flow in spacetime. A "time crystal", as has been used recently in science news.
The issue is that our everyday conception of stuff breaks down at the scale of string theory (and even quantum mechanics in general). A string is a millionth of a billionth of a billionth of a billionth of a centimeter. If an atom were magnified to the size of the solar system, a string would be the size of a tree. So asking about what the string 'looks like' at its own scale or what it's 'made of' is simply due to the limits of our experience and imagination.
You know how if you traced out your ancestry a whole bunch of generations, you'd get a "tree" My understanding with things at this level is that the strings are as much strings as that tree is a tree. And as much as that, they're as much actual things as that tree is. Like, if you wanted to, you could take an abstract description of a lot of systematic ideas, draw them out, and then make a garden of the different logical forms and structures they have. String theory is like that; it's really just a particular garden of logical structures. Our world is second order from logic. Quantum Field Theory describes our universe pretty well, and what it does is it describes particle physics as if particles are just excited states of the underlying physical fields that make up the universe. String theory is kind of like that, but the "particles" obey the math of "strings", even if they aren't strings in any sense that makes sense to us, in the same way the waves/particles of QFT don't act like anything we can experience at our scale but happen to fit the math of both waves and particles in different situations. If you see the mathematical structure as primary, maybe you can imagine strings as existing at the realm of pure logic, and everything about our world has emerged from that. Sort of how like you can get skyrim or something out of the 1s and 0s and logical gates in your computer, only there isn't really anything like the metal in the analogy. It's not that we aren't real or anything because there isn't the world of metal and computer users in the analogy either, it's just that reality is a puff of logic.
NeonsStyle The easy path would be to detect a superpartner in a collider experiment. Of course this wouldn't happen if the lowest mass superpartner is still more massive than the upper limit of your collider, which may be the case with the LHC.
So, given that string theory supports multiple values for the cosmological constant (among other things), would it be fair to say that the Many Worlds interpretation of quantum mechanics is better suited for string theory than the Copenhagen interpretation?
String Theory and MWI have very little, if anything to do with one another, really. As for which interpretation - you can make up your own mind on that, but when you're learning QM, particularly the math side of things, use Copenhagen. It's best to learn with an objective collapse model and worry about the philosophical side of things later. (All interpretations of QM are equivalent, and worrying about which is the right one can just lead to confusion, particularly when you are learning.)
When learning Quantum Mechanics, shouldn't you first try to understand the Mathematics and the concepts in their simplest form before attaching an interpretation on it? I mean, shouldn't students be encouraged to have their own ideas on the physical or even philosophical basis of the Mathematical descriptions that we have ascribed to the experiments and observations? All I mean to say is, the Interpretation you choose to take for Quantum Mechanics is more than just a mere 'meaning' to what Quantum Mechanics is, but is also the physical reality in which you believe occurs with Quantum phenomena. I just think the 'philosophical side of things' is sometimes, and especially in this case, just as important as the Mathematics, Since the interpretation you choose, tells you what Physics you think is actually as at play.
'When learning Quantum Mechanics, shouldn't you first try to understand the Mathematics and the concepts in their simplest form before attaching an interpretation on it?' Yes, that's my point. That's why Copenhagen is the best interpretation for learning it, because it's a simple model that avoids many of the issues with the wave function and realism, and instead encourages the student to focus on the results of the interaction. Effectively, Copenhagen treats the process of collapse/decoherence as a black box and concentrates on deterministic outcomes. While I agree the philosophical side is important, it can confuse the issue when you are learning the math. 'Shut up and calculate' is the adage; worry about the implications once you have a better grasp of the fundamentals. Most (if not all) popular science descriptions of quantum mechanics are inadequate to describe the extent of the theory, and few would argue that the best practice is to try to avoid addressing the philosophical ramifications of a theory without a comprehensive understanding of said theory.
I understand what you mean when you say the Copenhagen interpretation is the best model to start off with while learning Quantum Mechanics. However, on a more personal note, I take philosophy to be the basis of all Mathematics and Physics, based on the work of Kant's Critique of Pure Reason, where he says that our knowledge of the Phenomenal World is based on Synthetic A priori knowledge. "So many people today - and even professional scientists - seem to me like someone who has seen thousands of trees but not seen the forest. A knowledge of the historic and philosophical background gives that kind of independence from prejudices of his generation from which most scientists are suffering. The independence created by philosophical insight is - in my opinion - the mark of distinction between a mere artisan or specialist and a real seeker or truth." - Einstein letter to Robert A. Thornton, 7 December 1944.
Have results from LHC effectively ruled out existence of Super Symmetric particles? If so does that mean String Theory (or M Theory) is now proven to be missing a crucial prerequisite? And same question goes for Loop Quantum Gravity and Twister Theory.
So what about this new particle that was discovered at the LHC recently which was 6 times bigger than the Higgs Boson? Is it a new particle (Graviton?) or an anomaly?
If you have not read *Roger Penrose Faith Fashion and Fantasy* or *Not Even Wrong by Peter Woit* or *The Trouble with Physics by Lee Smolin* then this is a counter to SuperStrings Theories over confidence. String Theory is not a final theory yet and it's not Back Ground independent and other issues. So as a non physicist I object to being sold this hype. I would prefer a little more caution expressed to the public.
Thank you for supporting the actual scientific method and not giving to a hype for a non-existent unfalsifiable theory. I wish there was more people like you in the scientific community.
So, the particles, that we can observe by measuring them, are those strings' end points and quantum jumps just show us how they flip? If yes, is this explaining why we see teleport, but actually we just see the other end point of the string?
From my understanding it's a bit more subtle, what we call "particle" is not actually a concrete little ball shaped thingy (like the endpoints of the strings) but rather just the result of the vibration of these strings. The strings themselves we never really see as I understand it.
A thousand years from now, long after science has proven that our universe was born from a giant, celestial turtle named Wally, they'll discover this old video and wonder how we could have been so stoopid.
Me and my class are currently studying polarisation of electromagnetic waves in A Level and the book contradicts itself and says that vertical waves are polarised with vertical rails and then says they're polarised with horizontal rails and we wondered if you would be able to give us the correct answer. Thank you!
Look for the new edition of the book. Usually there they have the "errata" section where they talk about the mistakes found in the last edition. Or contact the author. Or look for the same subject in another book.
13:00 No. No scientist would interpret the size of the string landscape as a virtue of the theory. 13:10 Straw man. Nobody says String Theory isn't testable. The argument is it's not *uniquely* testable. String Theory isn't the only candidate unification of GR and QM which predicts the symmetries of Special Relativity. For a new theory to be considered (uniquely) "testable", it must make *unique* predictions compared to other candidates and/or currently accepted theories.
I don't really get how you do scatter strings. Like, if they're undivisible, how should they break when they crash? Or is it like you are scattering a bunch of strings against another bunch of strings?
The theory of Erik Verlinde on emergent gravity opens up a lot, but as of now, it is only a start. It will take many years to see if it holds. If so, then maybe people will start to build upon it. As of now, it is not ripe yet.
These intuitions brought to light by the interpretations of the mathematics of String Theory are all so incredibly beyond me. What a world mathematics has presented to us to understand. Almost too good. Tbh I'm a Verlinde/Susskind advocate, but kind of like the worldview Max Tegmark (MIT) holds regarding mathematics and reality, I believe the mere possibility of the existence of Strings could very well pop into existence by virtue of our attempt to observe it.
Since when is graviton a sure thing? Did I missed on some king of revolution, cause I got used to an idea that both particle and Einstenian interpretations of gravity are considered equel.
It's a tradition in quantum mechanic, if you have a force working, you assign a particle to it as force carrier. Gluon to carry strong, photon to carry electromagnetic, the stuffs. Whether it has theoretical groundwork doesn't matter right now. The work is ongoing to define graviton. So, until somebody come up with a way to detect it, it simply a convenient placeholder people can use to refer that particular force carrier.
I'm confused. What I've read leads me to think that CERN is operating at energies that should be finding supersymmetric particles and that if the energies of supersymmetric particles are much greater that it begins to cause problems with string theory: Am I missing something?
Particles are points and have zero dimensions. Strings have a length, are thus one-dimensional. They are indivisible. Strings are not made out of anything. According to current string theory, they just are there.
A nucleon spinning very very fast behave like a string. Think of a pizza doe. First it is a sphere and then you stretch it with rotation. In this case, rotating nucleon produces a string.
How the fuck can a point be 0 dimensional? Anything that’s 0 dimensional doesn’t exist; heck 1-dimensional things could be considered unexisting… or maybe just invisible…
is there a mathematical or theoretical justification for why strings are considered fundamental? is it not possible for the universe to just break down infinitely? the idea that things neatly end at a certain point seems like wishful thinking on the part of humans. we said the same thing about atoms and now here we are. it seems like we're going to be proven wrong about strings' fundamentality in the future too.
Yes there is a physical reason for it. The size of strings are at the Planck Length Scale which is the smallest unit of length possible. Planck units are fundamental units of nature and anything beyond the Planck scale doesn't resemble our reality at all and every physical law we know of breaks down if we go furhter beyond a Planck unit. No one really knows, but it's possible time, space and distance doesn't even exist on Sub-Planckian level. That's why it's reasonable to believe that strings are the smallest possible. So you can't break down anything inefinitely, latest theories suggests even space itself is not continuous but quantized with an "atomic-like" structure, where it's "atoms" are of the Planck-length..
TheMercury79 I used to think that plank length wasn't actually the fundamental scale, it was just that our current understanding of physics and our laws fail below plank length
I'm far from being an expert on this stuff, barely understand it. But I think there's a simple way to view it that makes sense - space (or spacetime) itself *is* the indivisible / the "atom" / the fundamental smallest unit of existence. And by that I mean the Planck length and Planck time, beyond which you cannot divide space or time any further and still have it make any kind of sense. Like a pixel to the universe, and its refresh rate, both of which are inherently linked because an object must move at superluminal speed to go further than a Planck length in a Planck time. You can chop spacetime up totally arbitrarily, but there exists a lower (and maybe upper) limit to that. Simply because everything that truly exists must occupy space in order to exist (the exceptions to this - point-particles and singularities - are simplifications and signs we don't fully understand those things yet, they still must have a size IMO). So the smallest unit of space that an object can occupy is the smallest object that can exist, the true "atoms" must be at least this big. I don't think we will just keep finding smaller and smaller things forever, if we find something less than that - we know that it's truly fundamental. If it is composed of yet smaller things, then those will be completely beyond the absolute limit of our understanding - ideas like time, space, causality, and even maths itself won't make sense beyond that. But it is undeniable that all natural sciences have shown a consistent pattern of finding things more fundamental than what we previously believed to be fundamental. In biology we went from organisms to cells to organelles to macromolecules; then we go to chemistry and find molecules, covalent bonds, atoms, electrons and nuclei; then particle physics with nucleons, quarks and bosons. It's quite beautiful and seemingly-natural how it all links up, and that shows we're on the right track IMO. Though there are many mysteries to solve, especially at the smallest and largest scales, so I won't deny there might be smaller and larger things than our current limits (except beyond the Planck limit - where we just cannot understand anything beyond that point). TL;DR: Space itself, specifically the Planck length, is indivisible. Every such indivisible point/quanta of space could be seen as the real fundamental unit of existence. It can have properties/values but it cannot contain anything.
Why you want someone to attempt disproving string theory? Isn't it obvious? Accepting something as the truth and never questioning it is the death of all progress.
16:11 Basically, matter is made out of fermions, while the forces between them are carried by bosons. Two fermions, i.e. two matter particles, cannot occupy the same space at the same time.
So when does science declare a theory dead? More than 40 years there is talk of string and maybe 30 years of supersymmetry. Not a single shred of evidence is found. Not one prediction was confirmed. When you talk to string theory adepts, they say, oh, but it is so beautiful, it evolves naturally. Yeah, right. Evidence is what we need. I think that after 40 years it is safe to say that String theory is dead, mathematical beauty or not.
Ronald de Rooij That’s not how science works. It took millennia from the time atoms were predicted to the time their existence could be empirically proven. We disqualify hypotheses by ruling them out experimentally, not by declaring some arbitrary time limit on how long it takes to acquire the evidence to prove or disprove them.
That Feynman diagram... 6:16 You don't have electron-electron annihilation, do you? Change one of them (on each side) to a positron! Or what I think that you mean, rotate the graphic -π/2.
There's different conventions for Feynman diagrams. Often, including in this one, the time axis is from the bottom to the top. The labeling makes it clear in this case, otherwise the lines would represent positrons.
In the classical view (I ignore families for a moment) are different particles indeed different particles (e.g. quarks and leptons). The standard model is already quite complex ... so many different ELEMENTARY particles ? According to string theory what we perceive as different particles are simply different excitations of strings. Just as different notes from a violin result from different vibrations of the same violin string. Actually a nice idea. Issue is: proof / evidence, whatever you wanna call it. There's none whatsoever. Just a firm belief that it has to be that way.
A graviton is just another hypothetical particle in speculative quantum mechanics, which makes this entire video fall flat.And you don't even mentioned that fact. Sad.
Yea, I've noticed that it seems there's a lack of interest in graviton research. As if they don't want to find it because it would up end their beloved string hypothesis.(or just make it that much more complicated)
You'd have made the exact same argument about the Higgs and scalar fields (neither of which were well liked by the mainstream physics community when they were first proposed), only now it turns out they are real, so you're cool with them. As for "lack of interest" in graviton research, I think the main stumbling block is the billions and billions it will cost to construct the freaking huge particle accelerator that we think would be necessary to detect it, not any lack of interest from the physics community. Any such accelerator would likely have to be thousands of kilometres long, and as a practical matter, would almost certainly have to be built in space. We're a ways off that
Um, no, that's not how it works at all. The Higgs field is all pervasive, but the number of actual Higgs bosons detected by the LHC was like, a few dozen. Virtual particles that mediate a force, and the particles themselves are not the same thing.
Quantum mechanics is one of the least speculative, most well-substantiated theories in all of natural science. The reason there’s little interest in detecting individual gravitons is because gravity is so many orders of magnitude weaker than the other forces that building a device capable of detecting individual gravitons is far outside of our current technological capabilities. For instance, a graviton detector with the mass of the planet Jupiter placed in close proximity to a neutron star (a VERY strong source of gravity) would still need to operate for approximately a century to verify the existence of the fundamental particle. Unfortunately even that wouldn’t do the trick, as neutron stars also give off prodigious amounts of neutrinos, which (even being as weakly interacting as they are) are far easier to detect than gravitons. Thus, it would be virtually impossible to distinguish a graviton from all of those neutrinos. You’d need lead shielding with a thickness of light years to block all the neutrinos, so dense it would collapse into a black hole. So yeah, even with speculative technology in the distant future, the detection of individual gravitons may very well be difficult to the point of functionally impossible.
Does the shape and expansion of the universe already imply a 5th dimension? I find it very hard to think about this without a fifth dimension. I can easily picture a universe expanding without expanding into anything, but for all points to be moving apart would surely require this, wouldn't it?
ramiro: but in science "theory" makes true predictions that are falsifiable. String theory makes either no predictions or it makes all of them at once (non-falsifiability), that's why it is only a hypothesis unlike the theory of evolution for instance.
mvmlego1212: For example all of those that make the development of effective antibiotics still possible, if it didn't work, you would know it instantly. For more simply google "true predictions of the Evolution Theory"
Would a photon be one string or would it be a ripple in a sea of strings? Is it made up of many strings or maybe a string is made of photons? One thing about strings is that as the amplitude increases the wavelength decreases. With an actual rope or fabric amplitude and wavelength are inversely proportional. Which seems to be similar to light because the higher the frequency the greater the energy but perhaps not because of the frequency but due to higher frequencies having greater amplitude.
Each photon would be a string. The frequency of the string is what makes it a photon, and not an electron or a graviton or a quark or a higgs. The frequency of the string has nothing to do with the frequency of the photon.
Okay, I've watched the video, now lets read the comments and see what the experts have to say.
I love this comment
Yes, "experts".
iSquared lol
Gumbo Clay idiot
Gumbo Clay ironic
"Darling, do you know where i've put my other six Dimensions again?"
-"Gosh, does that really matter? You barely even use them!"
WOW -1/12 views I've never been so late!
vladomaimun kek
that was a funny meme
+vladomaimun I get it. I see what you did there and I like it!
Hrithik Diwakar
The sum of all integers is -1/12
I get it.
I love how he's like "Yeah, 6 other dimensions. No big deal, really..." at the end :D
Yeah, pretty hilarious how he just waved that away.
Those strings you showed in your animation, I see them all the time floating in my vision
String theory proven👌👌👌👌👌
MaxArceus "cocaine is a helluva drug" - Rick James
It's been before our eyes this whole time!
Oh squiggly line in my eye fluid.
I see you lurking there on the periphery of my vision.
But when I try to look at you, you scurry away.
Are you shy, squiggly line?
Why only when I ignore you, do you return to the center of my eye?
Oh, squiggly line, it’s alright, you are forgiven.
MaxArceus lol, we all do.....
*+Renzo _* Nice :D
I understood some of these words.
I understood the number 4 in one of the equations 💪
Casually suggests that the entire universe is on a membrane of a higher dimension, claims it to be “not really a problem”
That's far easier to fix than the cosmological constant problem.
@@Sammusg WHY ELECTROMAGNETISM/ENERGY IS UNIFIED AND BALANCED WITH/AS WHAT IS GRAVITY:
Gravity AND ELECTROMAGNETISM/ENERGY are LINKED AND BALANCED opposites, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Therefore, Einstein's equations and Maxwell's equations are unified (given the addition of a fourth spatial dimension); AS E=mc2 is DIRECTLY and fundamentally derived from F=ma; AS TIME DILATION proves that electromagnetism/ENERGY IS GRAVITY. ACCORDINGLY, Einstein's equations predict that SPACE is expanding OR contracting in and with TIME; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. GREAT !!! (Very importantly, outer "space" involves full inertia; AND it is fully invisible AND black.)
Gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Accordingly, the rotation of the Moon MATCHES it's revolution. "Mass"/ENERGY involves BALANCED inertia/INERTIAL RESISTANCE consistent WITH/as what is BALANCED electromagnetic/gravitational force/ENERGY, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Accordingly, objects fall at the SAME RATE (neglecting air resistance, of course); AS ELECTROMAGNETISM/ENERGY IS GRAVITY.
Gravity IS ELECTROMAGNETISM/ENERGY. A PHOTON may be placed at the center of what is THE SUN (as A POINT, of course), AS the reduction of SPACE is offset by (or BALANCED with) the speed of light; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Energy has/involves GRAVITY, AND ENERGY has/involves inertia/INERTIAL RESISTANCE. THE SUN purely exemplifies time DILATION. INSTANTANEITY is FUNDAMENTAL. Time DILATION proves that electromagnetism/ENERGY IS GRAVITY, AS E=mc2 is DIRECTLY and fundamentally derived from F=ma. "Mass"/ENERGY IS GRAVITY. ELECTROMAGNETISM/ENERGY IS GRAVITY. Gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. GREAT !!!
The stars AND PLANETS are POINTS in the night sky. Let's compare this directly with BOTH a falling object AND the speed of light (c). Great. E=mc2 IS F=ma. Gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. GRAVITATIONAL force/ENERGY IS proportional to (or BALANCED with/as) inertia/INERTIAL RESISTANCE, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. Gravity IS ELECTROMAGNETISM/ENERGY. This NECESSARILY represents, INVOLVES, AND describes what is possible/potential AND actual IN BALANCE. Time DILATION proves that electromagnetism/ENERGY IS GRAVITY, AS E=mc2 is DIRECTLY and fundamentally derived from F=ma. INSTANTANEITY is FUNDAMENTAL to the FULL and proper understanding of physics/physical experience. Ultimately and truly, TIME is possible/potential AND actual IN BALANCE; AS ELECTROMAGNETISM/ENERGY IS GRAVITY. The ultimate unification of physics/physical experience combines, BALANCES, AND includes opposites, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. GREAT. It ALL makes perfect sense. THINK !!!
The Earth that undergoes time DILATION IS thus represented (ON BALANCE) as what is A POINT in the night sky, AS ELECTROMAGNETISM/ENERGY IS GRAVITY. (So, notice that the BLUE SKY IS no longer visible. Think.) E=mc2 IS F=ma. It is FULLY proven. Gravity IS ELECTROMAGNETISM/ENERGY. ELECTROMAGNETISM/ENERGY IS GRAVITY. Alas, the INTEGRATED EXTENSIVENESS of THOUGHT (AND description) is improved in the truly superior mind. I have truly, CLEARLY, AND MATHEMATICALLY unified physics/physical experience. OVERLAY what is THE EYE in BALANCED RELATION to/WITH what is THE EARTH. (Notice the black space of THE EYE, AND the DOME of a person's eye is ALSO visible.) THE EARTH is ALSO blue. Again, E=mc2 IS F=ma. The stars AND PLANETS are POINTS in the night sky. Time dilation proves that E=mc2 is DIRECTLY and fundamentally derived from F=ma, AS electromagnetism/ENERGY IS GRAVITY. It ALL makes perfect sense. Gravity IS ELECTROMAGNETISM/ENERGY. ELECTROMAGNETISM/ENERGY IS GRAVITY. BALANCE AND completeness go hand in hand.
By Frank DiMeglio
Now make "The Case Against String Theory"!
H. Sch. Which is fine, nay sayers and experimentalists can also lead to progress or at least sift out false theories. Never understood why people act so condescending about them.
You wanted to say: "no real case except its predictions that match low-energy as well as high-energy experiments, and some predictions that exceed the energy levels we can experiment with today, but would constitute a strong case for or against string theory if we ever go that far; oh, and being the only workable theory of quantum gravity in existence"
@@hasch5756 String theory touches on many branches of mathematics which are described as quite beautiful. String theory itself is quite UGLY. As "mathematics" it resembled a big giant ugly hairball. I know what beautiful mathematics IS and I know how to do these string theory calculations. These calculations are rote, tedious, boring, unenlightening. String theory as it exists right now is NOT an elegant theory. Far from it.
@@hasch5756 actually you are just plain wrong, don't claim things you do not know.
Try: PBS Space Time - Why String Theory is Wrong
Great video! Please, more of these lengthy interviews :) Showing the natural progression of theories really help a great deal in understanding (to my limited extent) this material.
the problem I keep encountering with arguments for string theory is that they usually boil down to "the maths is nice". It would be nice to maybe get a video on the case for an alternative theory as well, just for variety.
I'd like to see something that explains "what experiment could we do that would differentiate between the Standard Model and String theory?". ie, if Standard and String can't both be right, how can we prove one wrong?
@@johnblankenhorn9730 All you have to do is discover any one of the supersymmetric particles. That would pretty much do it.
@@johnblankenhorn9730 someone tell me if I'm wrong but I don't think string theory debunks the Standard Model at all... its more like a level below the standard model.. I'm pretty sure the ultimate complete string theory model would/should encompass the the standard model, which is build based on quantum mechanics or quantum field theory.... and then also should reproduce General Relativity.. Infact if It didn't reproduce some or most aspects of those models it would be a sure fire sign that string theory is COMPLETELY wrong... that is the point of a "THEORY OF EVERYTHING after all...
remember for the maths of a physics system to "be nice" it also has to accurate describe the system it's describing, which string theory does, apparently
This is probably my favourite vid made by this channel up to now. Please make more like this.
Are you going to do The Case for Loop Quantum Gravity next?
There is no way I'd do that! 😜
Haha! Well, I meant Brady. Obviously for the actual speaker, someone from the "other camp" would be needed to make an equally enlightening and passionate case for the correct theory as you did for the sadly misguided one ;þ
I feel like you should have at least mentioned it, instead of saying there are no other alternatives to String Theory. Also, to me background dependece is very much a problem of st that you should have talked about. Still, a nice video, really hope they're gonna get Rovelli to talk about LQG next. Have a nice day!
"instead of saying there are no other alternatives to String Theory" What? He literally says "What is the correct theory of quantum gravity? Is it string theory or is it one of the suggested alternatives?"
I'm sorry, I watched the video again, and I mixed up the parts of the videos where he's talking about alternatives for quantum gravity and solutions to putting together qm and sr. I still think he should have mentioned LQG. Have a nice evening.
p.s. (that's what happens when you comment online while being too tired and sleepy, my bad)
1:30 no no No NO! Damn it. Aristotle did not come up with atoms. In fact, he was OPENLY AGAINST the idea of atoms (brought up by other ancient Greeks like leucippus and Democritus). Aristotle was wrong about almost EVERYTHING relating to science. I just don't understand why people always think of him as some scientific genius and always falsely give him credit for stuff.
They must have forgotten the very handy rule: ARISTOTLE IS ALWAYS WRONG!
If you want a really in depth critique of Super String theory, I suggest you read Peter Woit's book Not Even Wrong. Its a great review of the mathematics and history of ST. The math references can be a bit challenging, but it is well worth the effort for the serious student. The book ends with an overview of how ST became so entrenched in academia that it became self-sustaining in spite of St's utter failure to even meet the orthodox criteria as a scientific 'theory'. I loved Richard Feynman's comment that "String theorists do not make predictions. They make excuses!".
Please do more string theory videos
There's a great book by the name of 'The Elegant Universe' by Brian Greene, that goes into a great deal of depth about Special/General Relativity, Quantum Mechanics, and string theory. It describes things in varying levels of complexity with some really great metaphors/analogies that are easy to understand. The book is a bit old and he's probably got more modern books with more contemporary emphasis, but I haven't read em.
I love the riffs you've put in between the different sections. Stringed instrument and all.
These longer videos are my favorite, hoping Ed Copeland returns with one soon too
Can you guys do a video on Verlinde's theory on dark matter? It seems rather interesting to me.
Indeed, it is about emergent gravity, though.
Niels Heldens YES PLEASE do this.
His paper suffers from many weak arguments. It has been debunked in several professional papers already and it has been shown in several publications how the predictions his theory makes deviates severely from measurements already made. Look up Sabine Hossenfelder's blog for more information.
arxiv.org/abs/1702.04355
I've seen a conference in Brussels with Verlinde, and I must say, yes, emergent gravity is pretty interesting and exotic, but has many problems. At some moments, Verlinde himself looked uncomfortable with his own theory.
I'd love to see the extra footage from this one, Brady.
Pretty please.
As I understand it, the trouble with String Theory is that in it, there can be several different "models" of the Universe, only one of which can be a model of the Universe we actually live in. Now, each "model of String Theory", if you will, gives different predictions about the results of experiments.
The trouble is this: we don't know which model of the Universe is our Universe, so if we'd even do an experiment that contradicts a model of String Theory, we could just say: _"Oh, so it isn't that model, then"_ and switch to another -- effectively making it impossible to fully disprove String Theory, which makes it more of an "excuse generator" (by lack of a better term) than a rigorous Scientific Theory.
"Regge behavior? Was the paper co-written by Bob Marley?
I kindly suggest that you consider a cosplay of AVGN.
Great Video Tony. Just like Maxwell, Einstein, Dirac and Higgs it shows how a mathematical exploration of current knowledge can suggest new things to look for, and where and how to look for them.
From my time at the university (the other members of our work group were mostly into loop quantum gravity) i remember the biggest complaint about string theory was never from the quantum side of particle interactions, but that it totally failed to provide a background independend generalization of general relativity and in fact even seemed to make it harder to construct such a mechanism.
It picked my interest, that you not even tangentially addressed this problem, when every thing that needs a quantum description of gravity at very high energies (black hole interiors, or the pre inflationary universe for example) need an actual description for the energy momentum tensor, or a framework to replace the field equations currently used to map general relativity.
Especially as a cosmologist, shouldn't those issues be also the nail you are hanging on, or has there been a major development that i missed, filling this significant void in the theory?
finally a good explanation of reasons that led to string theory for the general public, not the usual "hmmm, what if everything is made out of strings?" story
Dr Padilla awesome as always! Also congrats to you Brady, I found it to be one of the best Sixty Symbols videos you ever made! Keep it up!
I would be interested in how you make a case for gravitons since, by Einstein's Physics, gravity is the curvature of space-time. Therefore gravity is not actually a force, not in the sense that the strong or weak force is. So, there is no need for a 'graviton'. Please explain!
Excellent video, Sixty Symbols, as always. With PBS Spacetime now joining the party, it's great to see the coverage that physics is getting!
5 years later, there are so many physics channels it's legitimately a struggle to find and watch them all.
This is very nice Dr. Brady and Dr. Padilla. I'm looking on options for my masters and I'm exploring through some branches of physics out there. I'm divided between normal Astronomy / Planetary Science and Nuclear Cosmology / Particles. This was a very beautiful way to present string theory and other common subjects in Particle Physics, which gives it some nice points. Thanks.
Honestly string theory has always seemed to me (someone who is not a theoretical physicist) to be a very complicated and somewhat beautiful way to say absolutely nothing at all about how the universe works. If you can't test it or apply it, does it really mean anything at all?
My impression from the outside that it's not applicable or testable might be completely wrong though. If it is, I'd love to see a video about potential applications or experiments in string theory.
It predicted the viscosity of the quark gluon plasma, a calculation too difficult for quantum lattice simulation.
@@nmarbletoe8210 But it was superseded in those calculations by quantum chromodynamics
I'm not a physicist but i am a scientist. A theory that produces a whole landscape of models, which can be retrofitted to any experimental result is not predictive. I'm not saying it's wrong, but until they come up with a single model that predicts experimental results that we can check, it's not science but an excercise in maths, no matter how elegant the physicists find it.
there are many models, but they cannot explain just any old result. There are many results that would disprove string theory
I love the ending to this video it's so amazing. "Well some people criticize it because it predicts 10 spacetime dimensions. This isn't really an issue I mean the extra 6 could easily be wrapped up real small or something so don't worry about that." (paraphrasing obviously)
Acted a bit like Trump 6:00 It's great. it is fantastic. You will love this theory.
Daan Janssen Exactly my thoughts :D
people rejecting string theory. sad!
Here are a couple of things that trump has said about String Theory:
"We will have so much String theory if I get elected that you may get tired of String Theory, believe me. And you will say: please, its too much String Theory, Mr. president we can't take String Theory anymore, its too much. And I will say: No it isn't, we have to keep String Theory, we need to have more String Theory, we are going to have so much String Theory. Love you all, get out and vote!!"
"Mexico said they where not going to have any String Theory. My reply: The strings just got ten feet longer"
Make String Theory Great Again #MSTGA
It's tremendous.
This is a really great video. I love the formulas!
Dr Antony Padilla explains things really good and comfy. I love that
should it not be string hypothesis? :D
An hypothesis that has been tested but could not be refused, becomes a theory. Any theory is just a hypothesis that has not yet been disproven, despite trying.
liquidminds Not really the case. String theory is not a Scientific theory. Even by what you were saying, it hasn't been tested. it's a mathematical proof. It is nothing like a theory.
mathematical theories still undergo testing. The type of proof just looks different. It being mathematically proven, does not mean that it is proven to be valid in our reality though. That is an important distinction, I give you that.
@liquidminds That's not how that works. A theory is a description of the *why* of a process, the mechanics, the guts, the nuts and bolts. It is supported by hypotheses, which are if-then testable guesses. The theory comes in with the implication from those hypotheses. If your notion of hypothesis->theory is true, then what hypothesis is the theory of gravity?
Though not mentioned here but worth talking about, a law is just an observation which appears to be consistent. Law of gravity is "there always is a pull in this direction and it behaves like...". Theory of gravity is "there is a pull in this direction because...".
ok ok , so it is just a theory then :D
j/k i don't know how well tested it is, but would have assumed, if it is a theory, there would be no alternatives to it.
The Feynman Diagram @ 6:20 doesn't look right to me. Shouldn't it be one positron and one electron interacting with each other?
No, the diagram in the video is correct, it's a scattering process. The diagram I assume you are thinking of is an interaction process which would have a vertex as they join, producing a photon, which then splits back into an electron and a positron at another vertex.
You're right! This scattering is called Møller scattering. I don't have quantum mechanics until next semester :P
These videos keep my motivated to a career in physics. Seeing scientists talking about these cutting edge fields. Because sometimes it can be hard to maintain that inspiration in such a world and culture as we have.
Are you still achieving your dream?
I hope you still have your motivation and inspiration 😊
I’ve always enjoyed your videos. My algorithm hasn’t brought you to me in a long long time but I’m happy to see you today
Ya the end was pretty funny though I have to admit. 4 missing dimensions, nbd hahaha
I'd really like to see some videos on photonics/light. most of our technology is based on manipulating electrons, what interesting things may come from learning how to manipulate light the way we do with electricity.
17:19 What's six missing dimensions between friends?
This is my favorite Sixty Symbols video in a while. I appreciate the longer, more in depth videos, Brady!
I came here to find out why this theory came to be and he didn't explain that. He just said "natural progression" two times and that was it.
I like your videos, I'm studying physics at the undergraduate level and it's really nice to get information that's easy to process and closer to the big picture than the minutiae every once in a while
I love the last few seconds where he quickly mumbles something about 6 'missing' dimensions that aren't really a problem. I love it when people try to minimize things that don't fit what they choose to believe.
What is wrong with 10 dimensions.
I know it is now 11 dimensions and it isn't a hypothesis.
It is. The great 11 dimensional unifying M-theory does not even exist. It is just a dream, like a proof of the Riemann hypothesis, right now there are 5 kinds of string theories in 10d that are separate.
Can you disprove its existence with proofs against the current zeitgeist?
empCarnivore string theory is an unfortunately name because string theory isn’t an actual scientific theory, it’s a theory in the sense of mathematics. (Number theory, group theory, set theory) these things are not “proven” they are just a branch of mathematics.
Vikings488 and you know how mathematicians like to handle things. Always ready to create some random Axiom to make things fit the way they like
Hi, your video link to Objectivity at the end of the video appears to be broken. Cheers!
the thing i don't understand about string theory is what the strings actually are. what is the fundamental nature of a string? what is it made of? what is it's mode of existience? what does the vibration of the string look like on it's own scale?
You can think of particles like oscillations in their wave medium (higgs field, electromagnetic field, gravity field, etc). These oscillations interact with other oscillations in ways which we model using quantum field theory (QFT). These interactions cascade through the wave medium, causing new interactions at the locations of new interactions that propagate down the line.
Now what happens if this propagation line meets where it started and it starts propagating down space it's already been? You get what's called a standing wave. A standing wave is any time where a wave goes back on itself within a given space. Usually this is done by bouncing against a barrier of sorts and is most spectacularly observed with sand on a vibrating plate. At all frequencies of oscillation of the plate, there is a standing wave, but at certain oscillations based on the shape and material properties of the plate, the waves will line up and you get the special case of standing waves that everyone thinks about when talking about standing waves: the lines of sand in pretty shapes. There's a sixty symbols video on this topic.
Why am I talking about this? Because the same thing happens at the lower scales, the scales of particles. There is an oscillation in the quantum field which creates a standing wave (special case with lines, here) and this standing wave is relatively stable and will continue to oscillate until it decays internally (is such a thing actually possible in string theory? I'm just guessing when I say it'll decay) or is affected by its environment and loses its stability, until it reaches a new stable oscillation: the result of the particle interactions, or to use chemistry terms: the result molecule.
So to call it a string is more a description of the shape of the energy. It moves and bounces around according to QFT (or more accurately, the reality-process we model with QFT), but "it" is just a stable energy flow in spacetime. A "time crystal", as has been used recently in science news.
The issue is that our everyday conception of stuff breaks down at the scale of string theory (and even quantum mechanics in general). A string is a millionth of a billionth of a billionth of a billionth of a centimeter. If an atom were magnified to the size of the solar system, a string would be the size of a tree. So asking about what the string 'looks like' at its own scale or what it's 'made of' is simply due to the limits of our experience and imagination.
You know how if you traced out your ancestry a whole bunch of generations, you'd get a "tree"
My understanding with things at this level is that the strings are as much strings as that tree is a tree. And as much as that, they're as much actual things as that tree is.
Like, if you wanted to, you could take an abstract description of a lot of systematic ideas, draw them out, and then make a garden of the different logical forms and structures they have. String theory is like that; it's really just a particular garden of logical structures.
Our world is second order from logic. Quantum Field Theory describes our universe pretty well, and what it does is it describes particle physics as if particles are just excited states of the underlying physical fields that make up the universe. String theory is kind of like that, but the "particles" obey the math of "strings", even if they aren't strings in any sense that makes sense to us, in the same way the waves/particles of QFT don't act like anything we can experience at our scale but happen to fit the math of both waves and particles in different situations.
If you see the mathematical structure as primary, maybe you can imagine strings as existing at the realm of pure logic, and everything about our world has emerged from that. Sort of how like you can get skyrim or something out of the 1s and 0s and logical gates in your computer, only there isn't really anything like the metal in the analogy. It's not that we aren't real or anything because there isn't the world of metal and computer users in the analogy either, it's just that reality is a puff of logic.
i just want to know what is actually vibrating.
the field
How would you detect super symmetry?
NeonsStyle The easy path would be to detect a superpartner in a collider experiment. Of course this wouldn't happen if the lowest mass superpartner is still more massive than the upper limit of your collider, which may be the case with the LHC.
Thank you, another great video!
Could there be an experiment or a mathematical derivation, that proves String Theory wrong?
Nope, just add one more dimension and wait until it doesn't work, then add another, and so on.
@@stupidas9466 LOL :)
You mentioned photons being virtual particles, could you make a video / section of a video explaining this? I'd like to hear your thoughts
So, given that string theory supports multiple values for the cosmological constant (among other things), would it be fair to say that the Many Worlds interpretation of quantum mechanics is better suited for string theory than the Copenhagen interpretation?
String Theory and MWI have very little, if anything to do with one another, really.
As for which interpretation - you can make up your own mind on that, but when you're learning QM, particularly the math side of things, use Copenhagen. It's best to learn with an objective collapse model and worry about the philosophical side of things later. (All interpretations of QM are equivalent, and worrying about which is the right one can just lead to confusion, particularly when you are learning.)
Thank you for the clarification. Unfortunately I'm still on the hand-wavy conceptual side of learning about QM
When learning Quantum Mechanics, shouldn't you first try to understand the Mathematics and the concepts in their simplest form before attaching an interpretation on it? I mean, shouldn't students be encouraged to have their own ideas on the physical or even philosophical basis of the Mathematical descriptions that we have ascribed to the experiments and observations?
All I mean to say is, the Interpretation you choose to take for Quantum Mechanics is more than just a mere 'meaning' to what Quantum Mechanics is, but is also the physical reality in which you believe occurs with Quantum phenomena. I just think the 'philosophical side of things' is sometimes, and especially in this case, just as important as the Mathematics, Since the interpretation you choose, tells you what Physics you think is actually as at play.
'When learning Quantum Mechanics, shouldn't you first try to understand the Mathematics and the concepts in their simplest form before attaching an interpretation on it?'
Yes, that's my point. That's why Copenhagen is the best interpretation for learning it, because it's a simple model that avoids many of the issues with the wave function and realism, and instead encourages the student to focus on the results of the interaction. Effectively, Copenhagen treats the process of collapse/decoherence as a black box and concentrates on deterministic outcomes.
While I agree the philosophical side is important, it can confuse the issue when you are learning the math. 'Shut up and calculate' is the adage; worry about the implications once you have a better grasp of the fundamentals. Most (if not all) popular science descriptions of quantum mechanics are inadequate to describe the extent of the theory, and few would argue that the best practice is to try to avoid addressing the philosophical ramifications of a theory without a comprehensive understanding of said theory.
I understand what you mean when you say the Copenhagen interpretation is the best model to start off with while learning Quantum Mechanics. However, on a more personal note, I take philosophy to be the basis of all Mathematics and Physics, based on the work of Kant's Critique of Pure Reason, where he says that our knowledge of the Phenomenal World is based on Synthetic A priori knowledge.
"So many people today - and even professional scientists - seem to me like someone who has seen thousands of trees but not seen the forest. A knowledge of the historic and philosophical background gives that kind of independence from prejudices of his generation from which most scientists are suffering. The independence created by philosophical insight is - in my opinion - the mark of distinction between a mere artisan or specialist and a real seeker or truth." - Einstein letter to Robert A. Thornton, 7 December 1944.
Thank you Dr. Tony. That explanation was amazing and it helped me.
What if we just take quantum gravity...AND PUSH IT SOMEWHERE ELSE??
Even you don't know what you mean by that...
Have results from LHC effectively ruled out existence of Super Symmetric particles? If so does that mean String Theory (or M Theory) is now proven to be missing a crucial prerequisite? And same question goes for Loop Quantum Gravity and Twister Theory.
How about a similar video with a small introduction on Loop Quantum Gravity (LQG) and its "pros and cons"? Pleeeease!
Golly, I'm so overwhelmed by the sheer amount of String Theorists in the comment section. One video and everyone is an expert.
though im not convinced by string theory from the different views ive seen but this is the sort of explanation is what helps the laymen
So what about this new particle that was discovered at the LHC recently which was 6 times bigger than the Higgs Boson? Is it a new particle (Graviton?) or an anomaly?
If you have not read *Roger Penrose Faith Fashion and Fantasy* or *Not Even Wrong by Peter Woit* or *The Trouble with Physics by Lee Smolin* then this is a counter to SuperStrings Theories over confidence.
String Theory is not a final theory yet and it's not Back Ground independent and other issues. So as a non physicist I object to being sold this hype. I would prefer a little more caution expressed to the public.
Thank you for supporting the actual scientific method and not giving to a hype for a non-existent unfalsifiable theory. I wish there was more people like you in the scientific community.
I agree, and we should properly refer to it as "the string hypothesis". Too many hypotheses have the word "theory" in their title.
@@thrustvectoring8120 he's not in the scientific community though..
Thank goodness! Finally they have done a video on string theory. At last!
String theory makes my head hurt.
Simon Carlile it should
String Theory heads my hurt make.
So, the particles, that we can observe by measuring them, are those strings' end points and quantum jumps just show us how they flip? If yes, is this explaining why we see teleport, but actually we just see the other end point of the string?
From my understanding it's a bit more subtle, what we call "particle" is not actually a concrete little ball shaped thingy (like the endpoints of the strings) but rather just the result of the vibration of these strings. The strings themselves we never really see as I understand it.
A thousand years from now, long after science has proven that our universe was born from a giant, celestial turtle named Wally, they'll discover this old video and wonder how we could have been so stoopid.
So wrong. The turtle's name is A'Tuin.
+Caleb Mauer exactly.
Did you take that out of Stephen King's "IT"?
Me and my class are currently studying polarisation of electromagnetic waves in A Level and the book contradicts itself and says that vertical waves are polarised with vertical rails and then says they're polarised with horizontal rails and we wondered if you would be able to give us the correct answer. Thank you!
Look for the new edition of the book. Usually there they have the "errata" section where they talk about the mistakes found in the last edition. Or contact the author. Or look for the same subject in another book.
13:00 No. No scientist would interpret the size of the string landscape as a virtue of the theory.
13:10 Straw man. Nobody says String Theory isn't testable. The argument is it's not *uniquely* testable. String Theory isn't the only candidate unification of GR and QM which predicts the symmetries of Special Relativity. For a new theory to be considered (uniquely) "testable", it must make *unique* predictions compared to other candidates and/or currently accepted theories.
A brave little theory, and actually quite coherent for a system of five or seven dimensions -- if only we lived in one.
My cat loves string theory.
I don't really get how you do scatter strings. Like, if they're undivisible, how should they break when they crash? Or is it like you are scattering a bunch of strings against another bunch of strings?
Where does the theory of Erik Verlinde fit in?!
it fits in the realm of fringe science.
auch, not nobel prize science ?
The theory of Erik Verlinde on emergent gravity opens up a lot, but as of now, it is only a start. It will take many years to see if it holds. If so, then maybe people will start to build upon it. As of now, it is not ripe yet.
@Sixty Symbols. There's a typo on the second sentence of the description. i believe you meant "This is one". regardless.. awesome vid! loved it!
"Rules to the game"
I lost
Sorry, ppl... I had to state it out xD
FFFUUUUU-
I am not sure if I have won or lost since I haven't looked in a mirror yet
Dude come on I had been going strong for years. :(
Dam it I was winning until now.
These intuitions brought to light by the interpretations of the mathematics of String Theory are all so incredibly beyond me. What a world mathematics has presented to us to understand. Almost too good. Tbh I'm a Verlinde/Susskind advocate, but kind of like the worldview Max Tegmark (MIT) holds regarding mathematics and reality, I believe the mere possibility of the existence of Strings could very well pop into existence by virtue of our attempt to observe it.
Atomic Theory was not Aristotle, it was Democritus.
Can't be proved either way
Hi what is the name for the symbol that you use as Y in sixty, and do you Know what it means?? :))))
Since when is graviton a sure thing? Did I missed on some king of revolution, cause I got used to an idea that both particle and Einstenian interpretations of gravity are considered equel.
It's a tradition in quantum mechanic, if you have a force working, you assign a particle to it as force carrier. Gluon to carry strong, photon to carry electromagnetic, the stuffs. Whether it has theoretical groundwork doesn't matter right now. The work is ongoing to define graviton. So, until somebody come up with a way to detect it, it simply a convenient placeholder people can use to refer that particular force carrier.
@@masbaiy4858 it's not a convenient placeholder, you construct it mathematically as a multiplet, just as any other particle.
I'm confused. What I've read leads me to think that CERN is operating at energies that should be finding supersymmetric particles and that if the energies of supersymmetric particles are much greater that it begins to cause problems with string theory: Am I missing something?
Strings of what? What's the difference between a string and a particle?
Basically a (point) particle is zero dimensional while a string is one dimensional.
Particles are points and have zero dimensions. Strings have a length, are thus one-dimensional. They are indivisible. Strings are not made out of anything. According to current string theory, they just are there.
whatarewedoing Think of the fundamental particle as a harmonic oscillator.
A nucleon spinning very very fast behave like a string. Think of a pizza doe. First it is a sphere and then you stretch it with rotation. In this case, rotating nucleon produces a string.
How the fuck can a point be 0 dimensional? Anything that’s 0 dimensional doesn’t exist; heck 1-dimensional things could be considered unexisting… or maybe just invisible…
I enjoy these longer interviews but unlike Ed Copeland's this one leaves me more confused about string theory than when I started!
is there a mathematical or theoretical justification for why strings are considered fundamental? is it not possible for the universe to just break down infinitely? the idea that things neatly end at a certain point seems like wishful thinking on the part of humans. we said the same thing about atoms and now here we are. it seems like we're going to be proven wrong about strings' fundamentality in the future too.
Yes there is a physical reason for it. The size of strings are at the Planck Length Scale which is the smallest unit of length possible. Planck units are fundamental units of nature and anything beyond the Planck scale doesn't resemble our reality at all and every physical law we know of breaks down if we go furhter beyond a Planck unit. No one really knows, but it's possible time, space and distance doesn't even exist on Sub-Planckian level. That's why it's reasonable to believe that strings are the smallest possible.
So you can't break down anything inefinitely, latest theories suggests even space itself is not continuous but quantized with an "atomic-like" structure, where it's "atoms" are of the Planck-length..
Perfect, thank you.
No, the Planck length 1.6x10-35th power is a fundamental limit.
TheMercury79 I used to think that plank length wasn't actually the fundamental scale, it was just that our current understanding of physics and our laws fail below plank length
I'm far from being an expert on this stuff, barely understand it. But I think there's a simple way to view it that makes sense - space (or spacetime) itself *is* the indivisible / the "atom" / the fundamental smallest unit of existence. And by that I mean the Planck length and Planck time, beyond which you cannot divide space or time any further and still have it make any kind of sense. Like a pixel to the universe, and its refresh rate, both of which are inherently linked because an object must move at superluminal speed to go further than a Planck length in a Planck time. You can chop spacetime up totally arbitrarily, but there exists a lower (and maybe upper) limit to that. Simply because everything that truly exists must occupy space in order to exist (the exceptions to this - point-particles and singularities - are simplifications and signs we don't fully understand those things yet, they still must have a size IMO). So the smallest unit of space that an object can occupy is the smallest object that can exist, the true "atoms" must be at least this big. I don't think we will just keep finding smaller and smaller things forever, if we find something less than that - we know that it's truly fundamental. If it is composed of yet smaller things, then those will be completely beyond the absolute limit of our understanding - ideas like time, space, causality, and even maths itself won't make sense beyond that.
But it is undeniable that all natural sciences have shown a consistent pattern of finding things more fundamental than what we previously believed to be fundamental. In biology we went from organisms to cells to organelles to macromolecules; then we go to chemistry and find molecules, covalent bonds, atoms, electrons and nuclei; then particle physics with nucleons, quarks and bosons. It's quite beautiful and seemingly-natural how it all links up, and that shows we're on the right track IMO. Though there are many mysteries to solve, especially at the smallest and largest scales, so I won't deny there might be smaller and larger things than our current limits (except beyond the Planck limit - where we just cannot understand anything beyond that point).
TL;DR: Space itself, specifically the Planck length, is indivisible. Every such indivisible point/quanta of space could be seen as the real fundamental unit of existence. It can have properties/values but it cannot contain anything.
What a theory! It seems no matter what experimental results we get, string theory predicts almost all possible outcomes! The Nostradamus of physics.
Why you want someone to attempt disproving string theory?
Isn't it obvious?
Accepting something as the truth and never questioning it is the death of all progress.
16:11 Basically, matter is made out of fermions, while the forces between them are carried by bosons. Two fermions, i.e. two matter particles, cannot occupy the same space at the same time.
String Theory?
Pretty fucking smart.
But the intro stage in MegaMan X? FUCKING GENIOUS!!!
String theory in physics is like superman for civil defense.
Great if you have it, ridiculous to assume its true.
There's an additional dimension. The basic particle is the Moron. It's like the imaginary number, but not imaginary. -i, if you will.
so youre saying im a fundamental part of our universe? neat.
Some regions of space seem to have a much higher density of Morons than others.
I like those videos, 'cause the video itself is interesting, and the coments are soooo clever, i could just scroll through it all day
Gotta love the folks who disagree with the professional physicist about physics and then tout around his atheism as if it means something.
And you seem like the ordinary kind.
11 dimentions exist on Earth, but we live in a 3D universe.
I love this stuff.
I love the hand waving at the end.
So when does science declare a theory dead? More than 40 years there is talk of string and maybe 30 years of supersymmetry. Not a single shred of evidence is found. Not one prediction was confirmed. When you talk to string theory adepts, they say, oh, but it is so beautiful, it evolves naturally. Yeah, right. Evidence is what we need. I think that after 40 years it is safe to say that String theory is dead, mathematical beauty or not.
Ronald de Rooij That’s not how science works. It took millennia from the time atoms were predicted to the time their existence could be empirically proven. We disqualify hypotheses by ruling them out experimentally, not by declaring some arbitrary time limit on how long it takes to acquire the evidence to prove or disprove them.
That Feynman diagram... 6:16 You don't have electron-electron annihilation, do you? Change one of them (on each side) to a positron! Or what I think that you mean, rotate the graphic -π/2.
There's different conventions for Feynman diagrams. Often, including in this one, the time axis is from the bottom to the top. The labeling makes it clear in this case, otherwise the lines would represent positrons.
utl94 You are correct, but this were about e-e scattering and not annihlation. In the annihlation case you would have el&po in and two photons out
string theory = null theory
It's the Twizzlers theory.
that music was incredible. love the 80s BBC school sound
Typo in the formula at 10:00. Should be "stfu" in the denominator. (Yes, this is a joke.....)
You win the internet!
Shut the up
What's the difference between a string and a particle the actually exists as a string shape?
The string is smaller.
In the classical view (I ignore families for a moment) are different particles indeed different particles (e.g. quarks and leptons). The standard model is already quite complex ... so many different ELEMENTARY particles ?
According to string theory what we perceive as different particles are simply different excitations of strings. Just as different notes from a violin result from different vibrations of the same violin string. Actually a nice idea. Issue is: proof / evidence, whatever you wanna call it. There's none whatsoever. Just a firm belief that it has to be that way.
String theory has yet to predict something
Has this video been reuploaded, I feel like I have watched this exact video some time ago?
A graviton is just another hypothetical particle in speculative quantum mechanics, which makes this entire video fall flat.And you don't even mentioned that fact. Sad.
Yea, I've noticed that it seems there's a lack of interest in graviton research. As if they don't want to find it because it would up end their beloved string hypothesis.(or just make it that much more complicated)
You'd have made the exact same argument about the Higgs and scalar fields (neither of which were well liked by the mainstream physics community when they were first proposed), only now it turns out they are real, so you're cool with them.
As for "lack of interest" in graviton research, I think the main stumbling block is the billions and billions it will cost to construct the freaking huge particle accelerator that we think would be necessary to detect it, not any lack of interest from the physics community. Any such accelerator would likely have to be thousands of kilometres long, and as a practical matter, would almost certainly have to be built in space. We're a ways off that
That's why you go talk to engineers. Not a math course. We don't need an accelerator. If they exist there's billions of them flying around right now.
Um, no, that's not how it works at all. The Higgs field is all pervasive, but the number of actual Higgs bosons detected by the LHC was like, a few dozen. Virtual particles that mediate a force, and the particles themselves are not the same thing.
Quantum mechanics is one of the least speculative, most well-substantiated theories in all of natural science. The reason there’s little interest in detecting individual gravitons is because gravity is so many orders of magnitude weaker than the other forces that building a device capable of detecting individual gravitons is far outside of our current technological capabilities. For instance, a graviton detector with the mass of the planet Jupiter placed in close proximity to a neutron star (a VERY strong source of gravity) would still need to operate for approximately a century to verify the existence of the fundamental particle. Unfortunately even that wouldn’t do the trick, as neutron stars also give off prodigious amounts of neutrinos, which (even being as weakly interacting as they are) are far easier to detect than gravitons. Thus, it would be virtually impossible to distinguish a graviton from all of those neutrinos. You’d need lead shielding with a thickness of light years to block all the neutrinos, so dense it would collapse into a black hole.
So yeah, even with speculative technology in the distant future, the detection of individual gravitons may very well be difficult to the point of functionally impossible.
Does the shape and expansion of the universe already imply a 5th dimension?
I find it very hard to think about this without a fifth dimension. I can easily picture a universe expanding without expanding into anything, but for all points to be moving apart would surely require this, wouldn't it?
Verify its predictions experimentally, then call it a theory. For now, let's stick with string hypothesis.
You can never prove that a theory is correct. You can only show it is not wrong yet.
ramiro leal in this case you can't even show that it isn't.
ramiro: but in science "theory" makes true predictions that are falsifiable. String theory makes either no predictions or it makes all of them at once (non-falsifiability), that's why it is only a hypothesis unlike the theory of evolution for instance.
+GodmyX -- What predictions does evolution (specifically, common descent) make?
mvmlego1212: For example all of those that make the development of effective antibiotics still possible, if it didn't work, you would know it instantly. For more simply google "true predictions of the Evolution Theory"
Would a photon be one string or would it be a ripple in a sea of strings? Is it made up of many strings or maybe a string is made of photons? One thing about strings is that as the amplitude increases the wavelength decreases. With an actual rope or fabric amplitude and wavelength are inversely proportional. Which seems to be similar to light because the higher the frequency the greater the energy but perhaps not because of the frequency but due to higher frequencies having greater amplitude.
Each photon would be a string. The frequency of the string is what makes it a photon, and not an electron or a graviton or a quark or a higgs. The frequency of the string has nothing to do with the frequency of the photon.