People often say that the problem with string theory is that it doesn't make any prediction, but that's not quite right: the problem is that it can make almost any prediction you want it to make. It is really less of a "theory" in its own right and more of a mathematical framework for constructing theories.
One day some unusual observation will come along from somewhere, and that will be the loose end that allows someone to start pulling at the whole ball of yarn. Will this happen in our lifetimes? Unlikely, I think.
The problem is that once, a long time ago, String Theory was something that made concrete predictions that people just couldn't calculate.
Then people managed to calculate those predictions, and they were wrong. So the people working that theory up relaxed some constraints and tried again, and again, and again. So today it's that framework that you can use to write any theory you want.
That original theory was a good theory. Very compelling and just a small adjustment away from mainstream physics. The current framework is just not a good framework, it's incredibly hard to write any theory in it, understand what somebody else created, and calculate the predictions of the theories you create.
I was planning to make a similar comment. Conjecturing that some theory in the string theory landscape [0] gives a theory of quantum gravity consistent with experiments that are possible but beyond what humans may ever be capable of isn't as strong of a claim as it may first appear. The intuition I used to have was that string theory is making ridiculously specific claims about things that may remain always unobservable to humans. But the idea is not that experiments of unimaginable scale and complexity might reveal that the universe is made up of strings or something, it's just that it may turn out that string theory makes up such a rich and flexible family of theories that it could be tuned to the observed physics of some unimaginably advanced civilization. My impression is that string theory is not so flexible that its uninteresting though. There's some interesting theoretical work along these lines around exploring the swampland [1].
I am old enough to remember when string theory was expected to explain and unify all forces and predict everything. Sadly, it failed to deliver on that promise.
And there is no known single real world experiment that can rule out string theory while keeping general relativity and quantum mechanics intact.
More accurately, string theory is not wrong (because it just cannot be wrong). Because it does not predict anything and cannot invalidate anything, it does not help to advance our understanding of how to integrate general relativity and quantum mechanics.
It should not be called theory - maybe set of mathematical tools or whatever.
Or, that day will never come, because string theory isn't reflective of the actual world, or because there are so many theories possible under the string theory rubric that we can never find the right one, or because the energies involved to see any effect are far beyond what could be reached in experiment.
It isn't completely implausible that a future civilisation could perform the experiments to gather that data, somehow; but it is hard to envisage how we do it here on Earth.
Your implicit point is a good one. Is it sensible to have a huge chunk of the entire theoretical physics community working endlessly on a theory that could well end up being basically useless? Probably not.
There is not a "huge chunk" of the theoretical physics community working on string theory, and their never was. For one, it is far less common a topic of research now then it was earlier when it was more popular, but even then "huge" was really "a lot of universities had a grant for string theory investigation because it looked promising".
It mostly hasn't worked out and now people are moving on to other things.
The single worst thing that happened though was the populism: a small group of people with credentials started putting out pop-sci books and doing interviews, well in excess of what their accomplishments should mean. People are like "so many people are working on this" because there were like, 3 to 5 guys who always said "yes" to an interview and talked authoritatively.
Huge is a subjective term, but go and count the number of participants at Strings 2025 [1]. Then realise that is just one of many conferences [2]. It's still a very big field.
I definitely don't walk away from any of Brian Greene's content thinking that String Theory is anything close to a confirmed fact at all.
It's been some times since I read his earlier books, possibly his tone has changed?
I'll also say, I'm far from a professional physicist. I'm reading and watching for fun and intellectual curiosity, not to learn physics with the goal of doing my own research. I always thought of String Theory as being more of a study of math where many people have unsuccessfully tried to apply it to physics. And, that it's lead to some really interesting ideas. I just find him and his work really enjoyable.
Thanks for posting that; as soon as I saw the title here I was going to look that up if no one else had already. Sabine Hossenfelder too, though there's far too much content from her on this to put a list, but anyone interested might like some of her takes.
A few debates between Brian and other notables; Hossenfelder, Eric Weinstein, and Roger Penrose to name a few; have popped up in my youtube feed lately which are typically also engaging.
Hossenfelder is not really comparable to Collier. Collier's video is critical of string theory as a testable framework but she ultimately still supports people who do research in string theory. Most of her criticism is with media coverage of string theory, not the research or the researchers.
Hossenfelder has gone off the "the physics establishment is all idiots and they are suppressing the real physics" deep end and has converted specific complaints into trashing the entire field.
I'm not a fan of Hossenfelder, especially for casting quacks like Weinstein, but AFAICT she isn't about "suppressing the real physics" but more of a "establishment physics is wasting money and time, and a lot is equally bad/good as some alternative physics."
A year ago that might have been the case. Her more recent stuff is fairly dire. I believe that the algorithm encourages her and channels like hers to become more and more conspiratorial and less and less nuanced.
Don't agree, she spreads misinformation, she's disrespectful to other scientists and basically has resorted to just claiming that everything in academics is wrong. YouTube fame has completely radicalized her.
> Most of her criticism is with media coverage of string theory, not the research or the researchers.
I pretty strongly disagree with that categorization of Collier's video, as it makes it sound like string theorists were innocent bystanders and "the big bad media" just ran overboard.
I think she puts the blame squarely on string theorists (e.g. "celebrity string theorists who wrote all these books") as constantly hyping up the field with promises of "in a decade it will be amazing" - a phrase she uses to great dramatic effect throughout the video - despite never acknowledging the fact that it fails miserably at making testable predictions.
When she says "they lied to us", the "they" she's clearly talking about are specific researchers in the field (which she names), and the string research community more broadly, who are hyping up their field, not just "the media".
The problem with sabine is that she's become the worst person to make a correct point for the wrong reasons
If you do research it becomes pretty apparent that a high number papers are not great. There's varying issues, but a big one is that the funding model incentivises pumping out papers which are often of low quality, researching whatever happens to be in vogue at the moment
Literally everyone I've ever talked to in research as a frank conversation knows that this is a massive problem, but nobody wants to talk about it publicly. Research funding is already completely screwed as it is, and researchers are incredibly aware of how fragile their livelihoods are
Its clearly leading to a big reduction in the quality of the literature. I went on a replication spree recently and found that a pretty decent chunk of the field I was working in was completely unreplicable by me, with a few papers that I strongly suspect 'massaged' their results for various reasons
I wish someone would talk about this who wasn't also in bed with right wing grifters, and was actually credible. We need someone more like ben goldacre for physics
Sabine's most interesting content is the paper reviews, and where she sticks to actually examining the evidence - but it makes up a tiny fraction of what she produces these days, and her support for some truly grim figures is just gross
I agree with a part of Sabine's overall output, but she's increasingly misidentifying some of the problems and the solutions because she's drifted too far towards the grifters
To a large degree if you're trying to successfully trying to push for change, it really matters that the person pushing for it is credible. Someone like ben goldacre is able to credibly make a strong push for change within medicine because they've maintained credibility, someone like sabine makes the situation worse because they've chucked it away
Sabine's has a day job as a Youtuber, and she makes her videos from that perspective. She speaks her mind, makes a decent living, and educates some science nerds on the way. Seems pretty nice.
From the perspective of accomplishing institutional change in the academic physics world, this is does nothing. The institutional powers don't react at all to a complaining influencer with an Einstein doll.
And I suspect she's perfectly fine with that. Overturning the Physics establishment is a near impossible task. I would leave that for those mad enough to try.
The Planck scale where string theory's distinctive physics should appear is around 10^19 GeV. The LHC operates at about 10^4 GeV. That's a factor of 10^15 which is a million billion times too weak. No foreseeable accelerator technology can bridge this gap. The proposed Future Circular Collider (FCC) would reach maybe 10^5 GeV. Still 14 orders of magnitude short.
Non-Euclidean geometry (geometric axioms in which one postulate is rejected such that the 3 angles of a triangle are not exactly 180 degrees) was considered a meaningless word game and fundamental mistruth.
Later, non-Euclidean geometry was actually essential to modern physics.
It's intellectually sketchy to judge future value by the present.
Might as well fund someone researching whether quantum theory run on little gnomes, if there is no serious path to verification after 50 years, why not quantum gnomes?
On this topic (parallel postulate), it took ~2000 years from Euclid and then 3 people all came to the same conclusion independently within ~10-20 years.
> We should stop funding research into prime numbers. They're stupid and useless. Who cares about them, if they will never be used for anything? Number theory should be stopped, you may as well research gnomes.
I imagine this is what you would have sounded like 100 years ago.
You may be understating how much 15 orders of magnitude are.
The only truly exponential technological progress we’ve ever had, transistors, only scaled by ~5 orders of magnitude in feature size. Thermal engines went from maybe 0.1% to ~50%, less than 3 orders of magnitude, in about 200 years. There’s very fundamental physical laws that suggest that engines are done, and transistor scaling as we have known it for 30 years is also done. Perhaps very clever things might give us 5 more orders of magnitude? E.g. truly 3D integration somehow? Then we’re still 5 orders of magnitude off from our target. I can’t think of any technology that ever improved by more than 10^6, perhaps 10^9 if you count some derivative number (like “number of transistors on chip”, rather than actual size), and that’s from literally zero to today. Not from already-pretty-advanced to Death Star scale.
Another perspective is that, to get to those kinetic energies, we need accelerators as large as the solar system. Possibly the galaxy, I can’t quite remember. Will you concede that galaxy-wide objects are so far from current reality that there’s no point seriously talking about them?
you are mixing up gambling spend vs whole industry spend. If string theory was a small handful of people making up a small m*nority of physics departments like non-euclidea geometry research was that would be fine. Its huge swaths of most physics departments and a huge suck on research funding. For that kind of spend you better show results because you are in production phase at that point not lotto ticket moonshit phase. If we are buying lotto tickets with the money bey lots of different lotto tickets not a whole bunch of one lotto ticket
Is this a typo? I see a lot of words being censored these days and I assumed it's because of some algorithms and visibility. That shouldn't be the case here tho..
As a percentage of theoretical physicists it is probably significant though. A Better question is how much love/money/attention is going into rival theories ?
>Non-Euclidean geometry (geometric axioms in which one postulate is rejected such that the 3 angles of a triangle are not exactly 180 degrees) was considered a meaningless word game and fundamental mistruth.
This is just a lie though. Non-Euclidean geometry is a mathematical model of how distances behave on non-linear spaces. Nobody ever believed it to be a "fundamental mistruth", even suggesting it would look ridiculous. It would be akin to denying linear algebra, even the meaning is unclear.
That the physical reality of space is not linear was a shocking revelation, since all human experience and basically every experiment done up until that point indicated otherwise.
"Lobachevsky [mathematician contemporary of Gauss, who claimed parallel postulate was unnecessary] was relentlessly criticized, mocked, and rejected by the academic world. His new “imaginary” geometry represented the “shamelessness of false new inventions”"
Further, many claimed premature success in finding logical contridictions in geometry lacking parallel (Euclid's 5th) postulate; which meant they believed a 4-postulate geometry to be fundamentally false.
Yeah, even just trying chart a course on a ship across a reasonable distance will cause you to need to reevaluate some "obvious" things (like "what path is the shortest between these two ports" being a curve rather than a line).
String theory has always seemed intuitively wrong to me. From Wikipedia:
>In theories of particle physics based on string theory, the characteristic length scale of strings is assumed to be on the order of the Planck length, or 10E−35 meters
Yet electrons repel each other over distances of many meters by I think the virtual exchange of photons. How on earth would that work? How does your photo string know to head to an electron string trillions and trillions of times it's length away?
As far as I can tell the field became popular for sociological reasons that you could get grants for it and the like rather than any connection to reality(?)
You're being somewhat unfairly voted down, it's a legitimate questions because the popular media so grossly misrepresents what string theory is, especially in their visuals.
It's hard to visualise in 3D, but if you cut down the spatial dimensions to just 1D (a line), then theories like string theory just turn the infinitely thin mathematical line into a tube. You can picture a tube that vibrates, or has waves in its cross-section. Don't think of the the "strings" as actual little loops moving around in space, they're a modification of what space is.
You can even do the same kind of line->tube extension of a space with even more extra "loop" dimensions than the number of base dimensions. AFAIK the current theories have 10 total, of which 3 are the usual "large" dimensions of space, the rest are "small" and rolled up like the tube example.
Even so I don't get how electrons a meter apart interact through that stuff, as opposed to the electrical fields which spread out through space and so interact with other electrons as featured in quantum field theory which is what physicists use to actually calculate physical results, as opposed to string theory which fails to calculate actual physical results.
"if you cut down the spatial dimensions to just 1D" doesn't sound very physical to me.
I'm maybe being downvoted fairly. I studied physics and it don't think it's a misunderstanding of popularisation or that string theory is untestable, I just think it's straight wrong and not how the physical universe works.
> Even so I don't get how electrons a meter apart interact through that stuff
Very roughly: It's possible for point-like (or tiny looped) particles to interact as long as they take every possible path instead of just the one path that would cause a collision. How you interpret this is... up for debate. I prefer the many-world interpretation (MWI), but not everyone agrees.
> "if you cut down the spatial dimensions to just 1D" doesn't sound very physical to me
That's just a simplification to aid understanding, it's now how the theory actually works.
Yeah maybe. My flatmate of some years was doing a PhD in string theory at UT Austin along the lines of "if you cut down the spatial dimensions to just 1D" but he was a mathematician, not really a physicist and was ok with that if it produced interesting mathematics. For real physical things like wiring the lighting system I'd do it because he wasn't so good with that.
I think he went into string research because he was good at maths and there was grant money available for that rather than a deep belief that that was the nature of reality, which is kind of what I mean by sociological factors.
I think much string theory may be like that. Interesting maths but not good at figuring where electrons go.
Except this is how electrons actually go, and it has real testable consequences. The question I'm aware of (because it related to my degree in nanotechnology) was: are metals conductive at different dimensionalities?
Because at the nanoscale, you in fact can have 1D, 2D and 3D metals. 3D metals are bulk solids - like we're familiar with. 2D metals are planes of single (or very few) atoms. 1D metals are lines - think placing individual metal atoms down in a row - nanotubes are a practical example.
All real, possible structures to build.
When you do measurements on all these structures you get...weird answers. Like is a nanotube a superconductor? And the answer is...yes, but also no. Yes because you'll in fact view superconductivity like behavior, but no because actually it's a ballistic electron conductor - at the right energy level an electron bounces through the thing without hitting it, but not all electrons can do that at all energy levels, so you still measure a voltage across a nanotube between two conductors.
But a nanotube is 1D - we only have 1 dimension things move in (from one end to the other). So - conductive, not a superconductor, but you can kind of use it like one sometimes. And we know 3D metals are conductors - that's obvious right...so what are 2D metals? Presumably conductors right...?
And the answer is...nope, insulators - at least sometimes. And the reason is because the sum of all possible electron paths in a 2D metal is the electron always returns back to where it started - and those grow much faster mathematically then paths where the electron ends up somewhere else.
But only in 2D: in the 1D case most paths take you out of the conductor. And in the 3D case, the number of paths which land you somewhere else grows much faster then those which loop back, due to the extra dimension of freedom. But 2D metals are constrained - for any given path elsewhere, there are mathematically far more that land back where you started. This is observable, measurable behavior which is a topic of research for future semiconductors. Yet it's almost entirely quantum probability based behavior.
I think that's not quite right: it is reasonably certain that string theory can produce both the standard model and most extensions people have dreamt up, so the problem is rather that all the obviously "stringy" predictions are currently unavailable, while the string theory derived predictions for achievable experiments look like what we get from other theories we already have.
To make this valuable, it should produce a limited set including standard model. If you produce pretty much everything one can dream of, that does not carry predictive power.
What does string theory predict that (1) is within experimental reach in, say, 5 years (2) if not found, would prove it wrong. Was there ever anything satisfying these two simultaneously? AFAIK,the answer is "no".
But we've discovered a number of useful tools and techniques that are applicable to other areas of research have we not? The billions of dollars spent on string theory hype might have unlocked a strategy or technique that ends up being useful in a civilization changing way that we just don't know about yet. Maybe string theory and the hype it was able to generate was just the catalyst that we needed.
Compared to all the other useless endeavors we send our brightest minds to work on (optimizing ad sales, high frequency trading, crypto) I'd say physics research has the highest chance of being useful
What would Imre Lakatos say? Is it degenerating or not?
People often say that the problem with string theory is that it doesn't make any prediction, but that's not quite right: the problem is that it can make almost any prediction you want it to make. It is really less of a "theory" in its own right and more of a mathematical framework for constructing theories.
One day some unusual observation will come along from somewhere, and that will be the loose end that allows someone to start pulling at the whole ball of yarn. Will this happen in our lifetimes? Unlikely, I think.
The problem is that once, a long time ago, String Theory was something that made concrete predictions that people just couldn't calculate.
Then people managed to calculate those predictions, and they were wrong. So the people working that theory up relaxed some constraints and tried again, and again, and again. So today it's that framework that you can use to write any theory you want.
That original theory was a good theory. Very compelling and just a small adjustment away from mainstream physics. The current framework is just not a good framework, it's incredibly hard to write any theory in it, understand what somebody else created, and calculate the predictions of the theories you create.
I was planning to make a similar comment. Conjecturing that some theory in the string theory landscape [0] gives a theory of quantum gravity consistent with experiments that are possible but beyond what humans may ever be capable of isn't as strong of a claim as it may first appear. The intuition I used to have was that string theory is making ridiculously specific claims about things that may remain always unobservable to humans. But the idea is not that experiments of unimaginable scale and complexity might reveal that the universe is made up of strings or something, it's just that it may turn out that string theory makes up such a rich and flexible family of theories that it could be tuned to the observed physics of some unimaginably advanced civilization. My impression is that string theory is not so flexible that its uninteresting though. There's some interesting theoretical work along these lines around exploring the swampland [1].
[0] https://en.wikipedia.org/wiki/String_theory_landscape
[1] https://en.wikipedia.org/wiki/Swampland_(physics)
I am old enough to remember when string theory was expected to explain and unify all forces and predict everything. Sadly, it failed to deliver on that promise.
And there is no known single real world experiment that can rule out string theory while keeping general relativity and quantum mechanics intact.
More accurately, string theory is not wrong (because it just cannot be wrong). Because it does not predict anything and cannot invalidate anything, it does not help to advance our understanding of how to integrate general relativity and quantum mechanics.
It should not be called theory - maybe set of mathematical tools or whatever.
string boot framework
Or, that day will never come, because string theory isn't reflective of the actual world, or because there are so many theories possible under the string theory rubric that we can never find the right one, or because the energies involved to see any effect are far beyond what could be reached in experiment.
It isn't completely implausible that a future civilisation could perform the experiments to gather that data, somehow; but it is hard to envisage how we do it here on Earth.
Your implicit point is a good one. Is it sensible to have a huge chunk of the entire theoretical physics community working endlessly on a theory that could well end up being basically useless? Probably not.
There is not a "huge chunk" of the theoretical physics community working on string theory, and their never was. For one, it is far less common a topic of research now then it was earlier when it was more popular, but even then "huge" was really "a lot of universities had a grant for string theory investigation because it looked promising".
It mostly hasn't worked out and now people are moving on to other things.
The single worst thing that happened though was the populism: a small group of people with credentials started putting out pop-sci books and doing interviews, well in excess of what their accomplishments should mean. People are like "so many people are working on this" because there were like, 3 to 5 guys who always said "yes" to an interview and talked authoritatively.
Huge is a subjective term, but go and count the number of participants at Strings 2025 [1]. Then realise that is just one of many conferences [2]. It's still a very big field.
[1] https://nyuad.shorthandstories.com/strings-conference-abu-dh...
[2] https://www.stringwiki.org/wiki/Conferences
I thought Brian Greene did a great job interviewing Edward Witten (Fields Medal winner) on the World Science Festival Youtube channel [1].
I also just really enjoy Brian Greene, his books, and the World Science Festival Youtube channel.
[1] https://www.youtube.com/watch?v=sAbP0magTVY
You might not like Angela Collier's video on string theory[1].
[1]: https://m.youtube.com/watch?v=kya_LXa_y1E
Interesting, thanks for sharing!
I definitely don't walk away from any of Brian Greene's content thinking that String Theory is anything close to a confirmed fact at all.
It's been some times since I read his earlier books, possibly his tone has changed?
I'll also say, I'm far from a professional physicist. I'm reading and watching for fun and intellectual curiosity, not to learn physics with the goal of doing my own research. I always thought of String Theory as being more of a study of math where many people have unsuccessfully tried to apply it to physics. And, that it's lead to some really interesting ideas. I just find him and his work really enjoyable.
Thanks for posting that; as soon as I saw the title here I was going to look that up if no one else had already. Sabine Hossenfelder too, though there's far too much content from her on this to put a list, but anyone interested might like some of her takes.
A few debates between Brian and other notables; Hossenfelder, Eric Weinstein, and Roger Penrose to name a few; have popped up in my youtube feed lately which are typically also engaging.
Hossenfelder is not really comparable to Collier. Collier's video is critical of string theory as a testable framework but she ultimately still supports people who do research in string theory. Most of her criticism is with media coverage of string theory, not the research or the researchers.
Hossenfelder has gone off the "the physics establishment is all idiots and they are suppressing the real physics" deep end and has converted specific complaints into trashing the entire field.
I'm not a fan of Hossenfelder, especially for casting quacks like Weinstein, but AFAICT she isn't about "suppressing the real physics" but more of a "establishment physics is wasting money and time, and a lot is equally bad/good as some alternative physics."
I think here more recent takes are not nearly as nuanced.
A year ago that might have been the case. Her more recent stuff is fairly dire. I believe that the algorithm encourages her and channels like hers to become more and more conspiratorial and less and less nuanced.
Yeah I think most of what (negative) people attribute to her is mostly her being hopelessly German.
Most, but not all
Don't agree, she spreads misinformation, she's disrespectful to other scientists and basically has resorted to just claiming that everything in academics is wrong. YouTube fame has completely radicalized her.
> Most of her criticism is with media coverage of string theory, not the research or the researchers.
I pretty strongly disagree with that categorization of Collier's video, as it makes it sound like string theorists were innocent bystanders and "the big bad media" just ran overboard.
I think she puts the blame squarely on string theorists (e.g. "celebrity string theorists who wrote all these books") as constantly hyping up the field with promises of "in a decade it will be amazing" - a phrase she uses to great dramatic effect throughout the video - despite never acknowledging the fact that it fails miserably at making testable predictions.
When she says "they lied to us", the "they" she's clearly talking about are specific researchers in the field (which she names), and the string research community more broadly, who are hyping up their field, not just "the media".
Collier made a video fairly recently where she showed disappointment that her videos are watched by people who also watch Hossenfelder.
https://youtu.be/miJbW3i9qQc
I thought her rant about bullshit papers was pretty convincing and poignant.
The problem with sabine is that she's become the worst person to make a correct point for the wrong reasons
If you do research it becomes pretty apparent that a high number papers are not great. There's varying issues, but a big one is that the funding model incentivises pumping out papers which are often of low quality, researching whatever happens to be in vogue at the moment
Literally everyone I've ever talked to in research as a frank conversation knows that this is a massive problem, but nobody wants to talk about it publicly. Research funding is already completely screwed as it is, and researchers are incredibly aware of how fragile their livelihoods are
Its clearly leading to a big reduction in the quality of the literature. I went on a replication spree recently and found that a pretty decent chunk of the field I was working in was completely unreplicable by me, with a few papers that I strongly suspect 'massaged' their results for various reasons
I wish someone would talk about this who wasn't also in bed with right wing grifters, and was actually credible. We need someone more like ben goldacre for physics
Sabine's most interesting content is the paper reviews, and where she sticks to actually examining the evidence - but it makes up a tiny fraction of what she produces these days, and her support for some truly grim figures is just gross
If I understood this, you agree with Sabine, but since she's "in bed with right wing grifters" she should not be listened to?
This is not very persuasive.
I agree with a part of Sabine's overall output, but she's increasingly misidentifying some of the problems and the solutions because she's drifted too far towards the grifters
To a large degree if you're trying to successfully trying to push for change, it really matters that the person pushing for it is credible. Someone like ben goldacre is able to credibly make a strong push for change within medicine because they've maintained credibility, someone like sabine makes the situation worse because they've chucked it away
Maybe it's like this:
Sabine's has a day job as a Youtuber, and she makes her videos from that perspective. She speaks her mind, makes a decent living, and educates some science nerds on the way. Seems pretty nice.
From the perspective of accomplishing institutional change in the academic physics world, this is does nothing. The institutional powers don't react at all to a complaining influencer with an Einstein doll.
And I suspect she's perfectly fine with that. Overturning the Physics establishment is a near impossible task. I would leave that for those mad enough to try.
The OP is about that video, though one wouldn't know it from a web page that won't download. I've put an archive.org link in the toptext now.
The Planck scale where string theory's distinctive physics should appear is around 10^19 GeV. The LHC operates at about 10^4 GeV. That's a factor of 10^15 which is a million billion times too weak. No foreseeable accelerator technology can bridge this gap. The proposed Future Circular Collider (FCC) would reach maybe 10^5 GeV. Still 14 orders of magnitude short.
So the grift can continue
Non-Euclidean geometry (geometric axioms in which one postulate is rejected such that the 3 angles of a triangle are not exactly 180 degrees) was considered a meaningless word game and fundamental mistruth.
Later, non-Euclidean geometry was actually essential to modern physics.
It's intellectually sketchy to judge future value by the present.
Might as well fund someone researching whether quantum theory run on little gnomes, if there is no serious path to verification after 50 years, why not quantum gnomes?
On this topic (parallel postulate), it took ~2000 years from Euclid and then 3 people all came to the same conclusion independently within ~10-20 years.
Progress is weird.
Ideally, one should explore all possibilities. It is remarkable how far "merely" predicting the next word has taken us.
That was constant progress with measurable goals, not "big things are coming decade from now" every decade.
> We should stop funding research into prime numbers. They're stupid and useless. Who cares about them, if they will never be used for anything? Number theory should be stopped, you may as well research gnomes.
I imagine this is what you would have sounded like 100 years ago.
You may be understating how much 15 orders of magnitude are.
The only truly exponential technological progress we’ve ever had, transistors, only scaled by ~5 orders of magnitude in feature size. Thermal engines went from maybe 0.1% to ~50%, less than 3 orders of magnitude, in about 200 years. There’s very fundamental physical laws that suggest that engines are done, and transistor scaling as we have known it for 30 years is also done. Perhaps very clever things might give us 5 more orders of magnitude? E.g. truly 3D integration somehow? Then we’re still 5 orders of magnitude off from our target. I can’t think of any technology that ever improved by more than 10^6, perhaps 10^9 if you count some derivative number (like “number of transistors on chip”, rather than actual size), and that’s from literally zero to today. Not from already-pretty-advanced to Death Star scale.
Another perspective is that, to get to those kinetic energies, we need accelerators as large as the solar system. Possibly the galaxy, I can’t quite remember. Will you concede that galaxy-wide objects are so far from current reality that there’s no point seriously talking about them?
you are mixing up gambling spend vs whole industry spend. If string theory was a small handful of people making up a small m*nority of physics departments like non-euclidea geometry research was that would be fine. Its huge swaths of most physics departments and a huge suck on research funding. For that kind of spend you better show results because you are in production phase at that point not lotto ticket moonshit phase. If we are buying lotto tickets with the money bey lots of different lotto tickets not a whole bunch of one lotto ticket
> m*nority
Is this a typo? I see a lot of words being censored these days and I assumed it's because of some algorithms and visibility. That shouldn't be the case here tho..
They do the same thing with the i in “doing” in another post. It seems like just a typo this person sometimes makes.
I think you are vastly overestimating the number of string physicists and how much their non-experimental research costs.
There's maybe a couple or few hundred-ish in the whole world that focus on it. And they don't need much money because it's pretty much all math.
As a percentage of theoretical physicists it is probably significant though. A Better question is how much love/money/attention is going into rival theories ?
In the 1700s, perhaps. But we have come a long way since that.
Yet, OP is repeating the same logical fallacy: the absence of a result is not a result of absence.
>Non-Euclidean geometry (geometric axioms in which one postulate is rejected such that the 3 angles of a triangle are not exactly 180 degrees) was considered a meaningless word game and fundamental mistruth.
This is just a lie though. Non-Euclidean geometry is a mathematical model of how distances behave on non-linear spaces. Nobody ever believed it to be a "fundamental mistruth", even suggesting it would look ridiculous. It would be akin to denying linear algebra, even the meaning is unclear.
That the physical reality of space is not linear was a shocking revelation, since all human experience and basically every experiment done up until that point indicated otherwise.
This is a generally known part of the history of mathematics.
> Nobody ever believed it to be a "fundamental mistruth"
https://math.libretexts.org/Courses/College_of_the_Canyons/M...
"Lobachevsky [mathematician contemporary of Gauss, who claimed parallel postulate was unnecessary] was relentlessly criticized, mocked, and rejected by the academic world. His new “imaginary” geometry represented the “shamelessness of false new inventions”"
Further, many claimed premature success in finding logical contridictions in geometry lacking parallel (Euclid's 5th) postulate; which meant they believed a 4-postulate geometry to be fundamentally false.
I imagine that elliptic geometry had some use before modern physics.
The specific controversy was whether without the parallel/5th postulate, there existed a logical contradiction, i.e. proving the parallel postulate
Yeah, even just trying chart a course on a ship across a reasonable distance will cause you to need to reevaluate some "obvious" things (like "what path is the shortest between these two ports" being a curve rather than a line).
Planck energy: ~10^19 GeV is approx 2 GJ per collision
Energy to vaporize Earth's oceans: ~4 x 10^27 J
For a Planck-scale linear collider at LHC-like collision rates (~10^8/sec):
Beam power requirement: ~2 x 10^17 W
With realistic wall-plug efficiency of ~1%: ~2 x 10^19 W
Annual energy consumption: ~6 x 10^26 J
At 1% efficiency, one year of operation would:
Vaporize about 15% of Earth's oceans
Or vaporize the Mediterranean Sea roughly 50 times
Or boil Lake Superior every 5 hours
Or one complete ocean vaporization every 6-7 years of operation
It's about 1 million times current global power consumption
Or about 50,000 Suns running continuously
Or 170 billion Large Hadron Colliders operating simultaneously
String theory has always seemed intuitively wrong to me. From Wikipedia:
>In theories of particle physics based on string theory, the characteristic length scale of strings is assumed to be on the order of the Planck length, or 10E−35 meters
Yet electrons repel each other over distances of many meters by I think the virtual exchange of photons. How on earth would that work? How does your photo string know to head to an electron string trillions and trillions of times it's length away?
As far as I can tell the field became popular for sociological reasons that you could get grants for it and the like rather than any connection to reality(?)
You're being somewhat unfairly voted down, it's a legitimate questions because the popular media so grossly misrepresents what string theory is, especially in their visuals.
It's hard to visualise in 3D, but if you cut down the spatial dimensions to just 1D (a line), then theories like string theory just turn the infinitely thin mathematical line into a tube. You can picture a tube that vibrates, or has waves in its cross-section. Don't think of the the "strings" as actual little loops moving around in space, they're a modification of what space is.
You can even do the same kind of line->tube extension of a space with even more extra "loop" dimensions than the number of base dimensions. AFAIK the current theories have 10 total, of which 3 are the usual "large" dimensions of space, the rest are "small" and rolled up like the tube example.
Even so I don't get how electrons a meter apart interact through that stuff, as opposed to the electrical fields which spread out through space and so interact with other electrons as featured in quantum field theory which is what physicists use to actually calculate physical results, as opposed to string theory which fails to calculate actual physical results.
"if you cut down the spatial dimensions to just 1D" doesn't sound very physical to me.
I'm maybe being downvoted fairly. I studied physics and it don't think it's a misunderstanding of popularisation or that string theory is untestable, I just think it's straight wrong and not how the physical universe works.
> Even so I don't get how electrons a meter apart interact through that stuff
Very roughly: It's possible for point-like (or tiny looped) particles to interact as long as they take every possible path instead of just the one path that would cause a collision. How you interpret this is... up for debate. I prefer the many-world interpretation (MWI), but not everyone agrees.
> "if you cut down the spatial dimensions to just 1D" doesn't sound very physical to me
That's just a simplification to aid understanding, it's now how the theory actually works.
Yeah maybe. My flatmate of some years was doing a PhD in string theory at UT Austin along the lines of "if you cut down the spatial dimensions to just 1D" but he was a mathematician, not really a physicist and was ok with that if it produced interesting mathematics. For real physical things like wiring the lighting system I'd do it because he wasn't so good with that.
I think he went into string research because he was good at maths and there was grant money available for that rather than a deep belief that that was the nature of reality, which is kind of what I mean by sociological factors.
I think much string theory may be like that. Interesting maths but not good at figuring where electrons go.
Except this is how electrons actually go, and it has real testable consequences. The question I'm aware of (because it related to my degree in nanotechnology) was: are metals conductive at different dimensionalities?
Because at the nanoscale, you in fact can have 1D, 2D and 3D metals. 3D metals are bulk solids - like we're familiar with. 2D metals are planes of single (or very few) atoms. 1D metals are lines - think placing individual metal atoms down in a row - nanotubes are a practical example.
All real, possible structures to build.
When you do measurements on all these structures you get...weird answers. Like is a nanotube a superconductor? And the answer is...yes, but also no. Yes because you'll in fact view superconductivity like behavior, but no because actually it's a ballistic electron conductor - at the right energy level an electron bounces through the thing without hitting it, but not all electrons can do that at all energy levels, so you still measure a voltage across a nanotube between two conductors.
But a nanotube is 1D - we only have 1 dimension things move in (from one end to the other). So - conductive, not a superconductor, but you can kind of use it like one sometimes. And we know 3D metals are conductors - that's obvious right...so what are 2D metals? Presumably conductors right...?
And the answer is...nope, insulators - at least sometimes. And the reason is because the sum of all possible electron paths in a 2D metal is the electron always returns back to where it started - and those grow much faster mathematically then paths where the electron ends up somewhere else.
But only in 2D: in the 1D case most paths take you out of the conductor. And in the 3D case, the number of paths which land you somewhere else grows much faster then those which loop back, due to the extra dimension of freedom. But 2D metals are constrained - for any given path elsewhere, there are mathematically far more that land back where you started. This is observable, measurable behavior which is a topic of research for future semiconductors. Yet it's almost entirely quantum probability based behavior.
I think the 1D mentioned in jiggawatts comment is a different thing to a confining electrons to a nanotube type of setup.
An in half a century we still haven't found a single actually testable prediction.
I think that's not quite right: it is reasonably certain that string theory can produce both the standard model and most extensions people have dreamt up, so the problem is rather that all the obviously "stringy" predictions are currently unavailable, while the string theory derived predictions for achievable experiments look like what we get from other theories we already have.
To make this valuable, it should produce a limited set including standard model. If you produce pretty much everything one can dream of, that does not carry predictive power.
What does string theory predict that (1) is within experimental reach in, say, 5 years (2) if not found, would prove it wrong. Was there ever anything satisfying these two simultaneously? AFAIK,the answer is "no".
Making a hard, arbitrary deadline is a pretty extreme thing to do. ie Higgs Boson was a lot longer between theory and experiment than this.
You write this as though reality is a 4X game and we're obviously wasting time not clicking on the other item in the tech tree to optimize the build.
But we've discovered a number of useful tools and techniques that are applicable to other areas of research have we not? The billions of dollars spent on string theory hype might have unlocked a strategy or technique that ends up being useful in a civilization changing way that we just don't know about yet. Maybe string theory and the hype it was able to generate was just the catalyst that we needed.
what didn't se develop because those people were working on string theory? That is an unanswerable question. It is also the important question.
Compared to all the other useless endeavors we send our brightest minds to work on (optimizing ad sales, high frequency trading, crypto) I'd say physics research has the highest chance of being useful
I wonder what Ed Witten would have accomplished if he had gone into another field instead of choosing to dedicate his life to mathematical physics.
Not sure if you're making a joke about this, but Ed Witten tried a number of fields before settling on theoretical physics.
You reminded me about this Abstruse Goose comic: https://web.archive.org/web/20230202225744/https://abstruseg...
Hasn't ChatGPT solved string theory yet?