String Theory: Are you a believer?

Well?

Personally, I if I were to believe any of them, it would have to be the Bosonic Theory. It's almost as elegant as the universe itself. :rolleyes: I also like the idea of both open and closed strings being present. (I hate tachyons though. :mad: )

Anyway, please voice your opinion.

Thanks.

cazeone

wheres the option for 'all of the above, plus 11-dimensional supergravity'?

Congoose

I'm not really qualified to comment, since I know know very little of the detailed physics involved (being more of an experimental type), but from what I've read (e.g. Brian Greene's book) I would say I think it's possible string theory is right. The fact that the graviton emerges naturally is an eye-opener, but I'm far from being convinced to be honest. So it's a 'no' from me.......for now.

Hasn't it had been shown that I, IIA, IIB, HO, and HE are just different versions of the same theory, (hence the whole M-theory thing)?

base2

Why do so many people love talking about this ****? Just because they read some ****ty pop science book they think they have to regurgitate part of it for all to see on the internet.

Congoose

Congoose wrote:

Hasn't it had been shown that I, IIA, IIB, HO, and HE are just different versions of the same theory, (hence the whole M-theory thing)?

Yes, but I'm also interested in seeing what version people think is right, or is most appropriate.

base2

base2 wrote:

Why do so many people love talking about this ****? Just because they read some ****ty pop science book they think they have to regurgitate part of it for all to see on the internet.

Well, I'm guessing you study at Maynooth then. :rolleyes:

base2

I have studied there yes. And guess what. Physics graduates don't talk about string theory that much. Only non physics people.

base2

base2 wrote:

I have studied there yes. And guess what. Physics graduates don't talk about string theory that much. Only non physics people.

Well, String Theory has only evolved in the last couple of years. So perhaps the Physics grads didn't talk about when you were there, but hopefully they do now. :rolleyes:

Besides, I'm not here to argue. I just want people's opinions. I thought this would be an interesting topic, so I posted it.

Civilian_Target

I'm not sure about string theory - it could be as real as relativity, but it could also be as real as ether. So I abstain

Spear

Civilian_Target wrote:

I'm not sure about string theory - it could be as real as relativity, but it could also be as real as ether. So I abstain

That's part of the problem though, it could be either since there's no way to verify it experimentally.

Son Goku

To be honest I don't have much faith in it.

It seems to be very retro-actively correcting of itself.
Also almost no innovations have been provided by consideration of physical reality, rather by mathematical justifications.
I see it as being driven by mathematical elegance and platonic idealism.
Which doesn't sit well with me as a hopeful physical model.

Well, String Theory has only evolved in the last couple of years. So perhaps the Physics grads didn't talk about when you were there, but hopefully they do now.
+
Well, I'm guessing you study at Maynooth then.

They are definitely not going to start teaching such an advanced topic at undergraduate level, especially an unproven one.
They usually don't even teach General Relativity.
And I don't think is unique to Maynooth, I really doubt most universities teach it as an undergraduate degree.

Capt'n Midnight

Deleted User wrote:

Well, String Theory has only evolved in the last couple of years.

What's new ?
which of your options wouldn't have been there a decade ago

and what happened to Atari Jaguar (secondhand console - sold as seen, no strings attached)

Capt'n Midnight

Capt'n Midnight wrote:

What's new ?
which of your options wouldn't have been there a decade ago

and what happened to Atari Jaguar (secondhand console - sold as seen, no strings attached)

Oh yeah! I always seem to leave out Atari Jagusr in my polls. :rolleyes:

And a decade is considered a couple of years ago.

Capt'n Midnight

Deleted User wrote:

And a decade is considered a couple of years ago.

:eek: Back where I come from two makes a couple and three makes a threesome

planck2

Son Goku wrote:

To be honest I don't have much faith in it.

It seems to be very retro-actively correcting of itself.
Also almost no innovations have been provided by consideration of physical reality, rather by mathematical justifications.
I see it as being driven by mathematical elegance and platonic idealism.
Which doesn't sit well with me as a hopeful physical model.


They are definitely not going to start teaching such an advanced topic at undergraduate level, especially an unproven one.
They usually don't even teach General Relativity.
And I don't think is unique to Maynooth, I really doubt most universities teach it as an undergraduate degree.

Son Goku is correct. The majority of universities don't teach general relativity at undergraduate level. UCD is unique within in Ireland that it does and that the course is quite substantive.

String theory is one of those out there topics in the search for a unified theory, it is by know means unique in this respect. Most theories that deal with the unification of quantum mechanics and general relativity are probably wrong in some respect. As far as I know I have never heard of string theory, lqg or any of the other candidates for a quantum theory of gravitation deal with dark matter/energy, which will have to be dealt with if we want a complete theory of physics.

base2

Pretty much all universitios teach General Relativity for a physics undergraduate course. Its a fairly standard topic.

planck2

Its not really, Maynooth for example teach some cosmology, but nothing like what is taught at UCD.Trinity don't teach it because the Professor there has been reitred for many years. Cork may to some extent, but if you take a list at what is taught in the relativity course at UCD you'll see that it is miles beyond anything being taught in the other universities.

Son Goku

Pretty much all universities teach General Relativity for a physics undergraduate course. Its a fairly standard topic.

In Maynooth there is a module containing General Relativity and Cosmology for the Astrophysics degree in third year.

However that module only approaches General Relativity by taking the Schwarzschild metric as a given and then describing Black Holes and orbits around spherically symmetric, static objects from there.

Tensors and the Field Equation itself are not used to derive the Schwarzschild solution.
So it is truly only a fraction of General Relativity.

In fourth year other metrics are taken as given and you are only told they come from the Field Equation.

As for other universities planck2 has already explained.
General Relativity is most definitely not a standard undergraduate topic.

planck2

Thank you Son Goku

nesf

Each college has it's specialites, mostly tied to the lecturers present in the college.

Also the treatment of General Relativity in UCC was ok, depending on the lecturer. Most of the broad points of general are covered in third year, and iirc in fourth year there was a much more in depth coverage of the topic, but this was not compulsory as a module iirc. I'll ask one of the professors I know in there next time I meet him, the course has changed since my days. They changed the entrance degree and I think some of the course has changed.

The fourth year modules for single hons. physics were a mixed bunch in the old degree, a bit all over the place. Some were insanely difficult, some were very accessable. Only 2 were compulsory I think.

I changed out of single honours physics in third year, so I don't have first hand experience of the final year modules. I'm going from memory and what my old class said and were doing. It was the old UCC Quantum Course that was the worst iirc. It's been a bit though since I did it, and my memory isn't the best these days.

nesf

Deleted User wrote:

Well, String Theory has only evolved in the last couple of years. So perhaps the Physics grads didn't talk about when you were there, but hopefully they do now. :rolleyes:

Besides, I'm not here to argue. I just want people's opinions. I thought this would be an interesting topic, so I posted it.

Short answer.

I've worked and been involved with the physics department of my old college both as a student and a researcher for the past 6 years.

No one talked about String Theory except people who read pop science books too much. It is not something that is regularily discussed by physics grads and undergrads except by a few doing work in a related field and by pretentious gits who want to sound intellegent.

I cringed when I say this thread title tbh.

It's just like Quantum. There are loads of pop science books on quantum around the place. Compare the understanding from those books to actually studying the subject from a mathematical basis. There are leagues of a difference between the two.

Don't get me wrong, talk about anything you want, but don't spout **** about it being grasped and talked about by undergrads and grads. I know very few people who can claim to have a genuine understanding of the concepts involved, it's not a simple or very accessable theory.

Then again, people who claim to understand Quantum also get my back up, so go figure.

ghostchant

I thought there was a professor in trinity who's main interest was in string theory but i don't go there so I'm not sure really

Son Goku

nesf wrote:

It's just like Quantum. There are loads of pop science books on quantum around the place. Compare the understanding from those books to actually studying the subject from a mathematical basis. There are leagues of a difference between the two.

If only people understood this.
I've had to listen to so many arguements in debates I've chaired that revolved around a pop-science understanding of Quantum Physics.
People think that reading "Six Easy Pieces" makes them an expert on the subject and they can see the flaws "silly old Einstein and them boffin guys" made in their work.

And as bad as it is for Quantum Physics, it's leagues worse for General Relativity.

nesf

Son Goku wrote:

If only people understood this.
I've had to listen to so many arguements in debates I've chaired that revolved around a pop-science understanding of Quantum Physics.
People think that reading "Six Easy Pieces" makes them an expert on the subject and they can see the flaws "silly old Einstein and them boffin guys" made in their work.

And as bad as it is for Quantum Physics, it's leagues worse for General Relativity.

I totally agree.

Discussions usually follow the following for me.

Random person: "Yeah read a few books on it, relativity is just the whole adding time as a dimension thing! Simple really, suprised no one thought of it before."
Me: *Puts head in hands*
Random person: "What? Going to be all elitist and say because I didn't study physics at college I can't understand it?"
Me: "Imagine a box. 3 dimensions yeah. Now add a fourth one. Describe what it looks like to me."
Random person: "I don't see what that has to do with anything, plus nobody can do that!"
Me: "My point exactly."


I just find the whole quantum analogy helps people get the idea. Most people who ask a physics grad about quantum realise very quickly that the image and thought experiment descriptions in pop science books really don't do anything to further one's understanding of what actually is happening.

It's the people who talk about proability fields without even the slightest clue of what they actually are talking about. Saw a pop-philosophy book where a guy was talking about the soul and was trying to make himself sound intellegent and add some "scientific-ness-ology" to his work by saying something along the lines of,

The soul can be viewed as transporting itself into the afterlife, this mechanism is very similar to that of any object having a chance of appearing around jupiter rather than staying on your table. Except with the soul, it is a definite rather than possibility.

The above made me laugh, then cry, then return the book to the shelf. I don't remember the title or author, was a few years back, but the memory still haunts me today.

Only thing that gets to me more is pop-psychology and psychobabble. That stuff is actually potentially dangerous, while the above is just laughable and embarassing when someone raises it as a serious argument in a serious debate.

nesf

ghostchant wrote:

I thought there was a professor in trinity who's main interest was in string theory but i don't go there so I'm not sure really

I have some memory twinging after reading that. I'm sure I heard about some professor in Ireland who was well into it.

I know one lecturer in UCC who was well into it. But he was different to say the least. Most of the lecturers had some passing knowledge of it, but iirc the maths involved is a bit "left field" for most of them. Lecturers tend to be very focussed in their area though, as one said to me,

"Relativity? Yeah I know a bit about it. Have never done anything with it though, always been a quantum man myself."

Son Goku

nesf wrote:

I totally agree.

Discussions usually follow the following for me.

Random person: "Yeah read a few books on it, relativity is just the whole adding time as a dimension thing! Simple really, suprised no one thought of it before."
Me: *Puts head in hands*
Random person: "What? Going to be all elitist and say because I didn't study physics at college I can't understand it?"
Me: "Imagine a box. 3 dimensions yeah. Now add a fourth one. Describe what it looks like to me."
Random person: "I don't see what that has to do with anything, plus nobody can do that!"
Me: "My point exactly."

Not to turn this into a "compare stories" thread but I've got the following:

Guy 1: The main flaw with General Relativity is that it doesn't define itself.
Me: What do you mean?
Guy 1: For instance, "curved space-time" that’s just ridiculous. Space can't be curved. Newton himself said it was fixed.
Me: Yes, but physics has moved on since Newton's day.
Guy 1: The arrogance of scientists never ceases to amaze me.
Me: Indeed.

Guy 2: I know the maths says you can't go faster than light but that’s just maths.
Me: Yes, but it is a mathematical description of the physical world. Each symbol has a well defined meaning. It is just occasionally difficult to put into words.
Guy 2: So your saying a bunch of maths is going to stop me from travelling really fast?! Oh, watch out the numbers are coming to get me!! *Bursts out laughing*
Me: Well, no...........................never mind.

And related to this thread:

Guy 3: So String theory, 11-dimensions. It's an obvious improvement on General Relativity. What if the Big Bang was just a big String unwinding itself?
Me: General Relativity is a pretty good theory and I'm not sure what you mean by "unwinding"
Guy 3: Yeah, but it's still just a theory, it's not proven. And you should really read up on String Theory if you want to know about the unwinding. A physicist should know.
Me: Eh,...yeah.

Anyway, from what I've heard from the philosophy department they have it even worse. Apparently the pop philosophy people come out with is terrible.

And I'm sure pop-theology is just as bad. As well as pop-any subject.

Sorry for de-railing the topic.

nesf

Son Goku wrote:

Not to turn this into a "compare stories" thread but I've got the following:

Guy 1: The main flaw with General Relativity is that it doesn't define itself.
Me: What do you mean?
Guy 1: For instance, "curved space-time" that’s just ridiculous. Space can't be curved. Newton himself said it was fixed.
Me: Yes, but physics has moved on since Newton's day.
Guy 1: The arrogance of scientists never ceases to amaze me.
Me: Indeed.

Guy 2: I know the maths says you can't go faster than light but that’s just maths.
Me: Yes, but it is a mathematical description of the physical world. Each symbol has a well defined meaning. It is just occasionally difficult to put into words.
Guy 2: So your saying a bunch of maths is going to stop me from travelling really fast?! Oh, watch out the numbers are coming to get me!! *Bursts out laughing*
Me: Well, no...........................never mind.

And related to this thread:

Guy 3: So String theory, 11-dimensions. It's an obvious improvement on General Relativity. What if the Big Bang was just a big String unwinding itself?
Me: General Relativity is a pretty good theory and I'm not sure what you mean by "unwinding"
Guy 3: Yeah, but it's still just a theory, it's not proven. And you should really read up on String Theory if you want to know about the unwinding. A physicist should know.
Me: Eh,...yeah.

Anyway, from what I've heard from the philosophy department they have it even worse. Apparently the pop philosophy people come out with is terrible.

And I'm sure pop-theology is just as bad. As well as pop-any subject.

Sorry for de-railing the topic.

Nice, needed a laugh I've stopped saying I studied physics nowadays, I just say I did applied maths and financial maths, it makes people's eyes glaze over and back away slowly. Plus I did kinda switch more into that direction and thats where my interests are today

It's not derailing, we're swapping stories about pop science and how it leads to idiocy.

And someone posted a poll on a BB about string theory and which flavour you prefer.

I think it's perfectly on-topic.

Although I could rephrase that as

"And someone posted a poll on a BB about [Insert Random Pop-Whatever Theory here] and which [generic label that makes it appear technical to people not in the know, here] you prefer."

But it was a bit too long so I thought I'd shorten it

David19

If you're still curious, the head of the maths department in TCD has string theory down as his research interest.

http://www.maths.tcd.ie/people/index.php?file=people&code=SSh

Also, TCD do have a general relativity course:

http://www.maths.tcd.ie/undergraduate/courses/index.php?file=442

Im not sure how in depth that is though. The description means nothing to me.

planck2

David19 wrote:

If you're still curious, the head of the maths department in TCD has string theory down as his research interest.

http://www.maths.tcd.ie/people/index.php?file=people&code=SSh

Also, TCD do have a general relativity course:

http://www.maths.tcd.ie/undergraduate/courses/index.php?file=442

Im not sure how in depth that is though. The description means nothing to me.

Thanks for letting me know that, I wasn't sure. There you have, GR is thought thoroughly by the two universities in Ireland.

And to those above, yes it is such a pain to come across ignorant people. I sympathise.

planck2

planck2 wrote:

Thanks for letting me know that, I wasn't sure. There you have, GR is thought thoroughly by the two universities in Ireland.

And to those above, yes it is such a pain to come across ignorant people. I sympathise.

I should say two of the universities in Ireland

Sev

Although, if there was anybody on this forum actually qualified to discuss string theory in any depth, could it be done without making broad sweeping statements akin to the scratch the surface generality of a pop-science book?

That said I do understand the cringe-worthiness of this thread. Ive finished 2 years of an undergrad course on Theoretical Physics and still am in absolutely no position to comment at all on haughty topics such as string theory and general relativity. We've only had a rather broad and general introduction to quantum physics and have scratched the surface of a mathematical foundation to quantum mechanics. As for special relativity, we did that in first year, and thats mere childs play in comparison.

It can only get tougher I guess, bring on 3rd year. I'll probably do a postgrad in this stuff, and maybe ill drag this thread back up in a couple of years with some actual material to discuss.

planck2

I don't think there would be any point as one would then be talking about conformal field theory, Vertex operator algebras, AdS/CFT dualities, S-dualities, T-dualities and the like and even before then you will have lost many

sean_0

I know one lecturer in UCC who was well into it. But he was different to say the least.

He he, I know who you're on about.

There is a fairly comprehensive introductory course in General Relativity in 4th year at UCC, I think they use Landau and Lif****z "Classical theory of Fields" as part of the course so it must be pretty thorough. I'm a postgrad at UCC but I've only taken the undergrad courses relevant to my research (Quantum stuff) and definately won't be taking that course any time soon.

It's just like Quantum. There are loads of pop science books on quantum around the place. Compare the understanding from those books to actually studying the subject from a mathematical basis. There are leagues of a difference between the two.

Yea, I know what you mean. Sometimes I'd love to bash some of those guys who carp on about it with a copy of Sakurai or something. Still though, you've got to start somewhere and having an interest in the subject is half the battle when it comes to dealing with the high level mathematical stuff.

Son Goku

Sev wrote:

That said I do understand the cringe-worthiness of this thread. Ive finished 2 years of an undergrad course on Theoretical Physics and still am in absolutely no position to comment at all on haughty topics such as string theory and general relativity.

This isn't really in response to you, but I knew three psychology undergrads who had an in-depth knowledge of General Relativity.
As well as a good deal of philosophers who learned the mathematics of quantum mechanics just so they could discuss it.
More importantly I know a lot of physics post grads who know nothing of their subjects.

Just to say that a degree in physics doesn't qualify one to discuss it.
A lot of people have degrees based of their ability to mentally regurgitate in an exam.

sean_0

Son Goku wrote:

This isn't really in response to you, but I knew three psychology undergrads who had an in-depth knowledge of General Relativity.
As well as a good deal of philosophers who learned the mathematics of quantum mechanics just so they could discuss it.
More importantly I know a lot of physics post grads who know nothing of their subjects.

No you didn't. You knew 3 psych undergrads who were full of s**t and you made up the rest. Idiot

simu

Keep it civil people!

ecksor

Too late, he's banned!

nesf

Son Goku wrote:

T
A lot of people have degrees based of their ability to mentally regurgitate in an exam.

This is my problem with college in general. An ability to regurgitate doesn't mean someone is intelligent. Actually this is something that gets some people quite angsty... (see above)

Insecure about our intelligence are we?

Sev

Son Goku wrote:

This isn't really in response to you, but I knew three psychology undergrads who had an in-depth knowledge of General Relativity.
As well as a good deal of philosophers who learned the mathematics of quantum mechanics just so they could discuss it.
More importantly I know a lot of physics post grads who know nothing of their subjects.

Well half the reason I cant comment on general relativity or quantum mechanics at the moment is because, in place, ive done two years of maths. Two years of linear algebra and analysis etc. Now I'd hope this isnt all irrelevant, and when I finally do get down to the nitty gritty of quantum mechanics.. hamiltonians, commutative groups and vector subspaces might begin to take on new meaning. But I'd imagine, or hope at least, with a rigorous mathematical background in place im going to have a better grip of things than your 3 psychology friends.

I could be wrong. If I had it my way, I would have skipped the tedium of analysis and algebra this year. But I'd like to think that its something that you have to learn, and that the psychology man with the casual interest will always be lacking, cos unlike me, he wasnt forced to learn the groundwork.

nesf

Sev wrote:

But I'd like to think that its something that you have to learn, and that the psychology man with the casual interest will always be lacking, cos unlike me, he wasnt forced to learn the groundwork.

My honest take on this is as follows:

A degree doesn't really mean you understand anything better than someone with a lay interest. What it means is that you have a good general understanding of most of the basics and intermediate topics of the subject. The key word being general.

It would be easy for a lay man to have a better understanding of general relativity than you. It's a niche, it's easy to know a lot about a niche.

Having a good grasp of all the basic subsets of physics and all the mathematical tools that you might need is very different. That would be a tough task to achieve for someone who didn't do a degree in a topic. It would take many years to get that kind of knowledge in your spare time. There are lay people out there that dedicate quite a lot of their spare time to their pet interest, but they are rare.


A perfect example is as follows. In psychology/psychiatry I have an indepth knowledge on certain topics, particularily pharmacology, certain disorders and the like. I know these topics better than a psych grad. But I do not know psychology generally as good as a psych grad if that makes sense.

I would know little about interview technique, the history of psychology and little on anything but the few topics that I've an interest in.

That is the difference between a lay interest and an academic background in a topic.

Sev

Can't argue with that.

nesf

Sev wrote:

Can't argue with that.

I get that a lot. It's no fun, means I kill thread half the time!

Son Goku

I should probably clarify what I mean.

A subject is usually only understood by those with extreme interest in it.
The majority of those with degrees aren't really interested.

No you didn't. You knew 3 psych undergrads who were full of s**t and you made up the rest. Idiot

What brings you to that conclusion?

David19

nesf wrote:

My honest take on this is as follows:

A degree doesn't really mean you understand anything better than someone with a lay interest. What it means is that you have a good general understanding of most of the basics and intermediate topics of the subject. The key word being general.

It would be easy for a lay man to have a better understanding of general relativity than you. It's a niche, it's easy to know a lot about a niche.

Having a good grasp of all the basic subsets of physics and all the mathematical tools that you might need is very different. That would be a tough task to achieve for someone who didn't do a degree in a topic. It would take many years to get that kind of knowledge in your spare time. There are lay people out there that dedicate quite a lot of their spare time to their pet interest, but they are rare.


A perfect example is as follows. In psychology/psychiatry I have an indepth knowledge on certain topics, particularily pharmacology, certain disorders and the like. I know these topics better than a psych grad. But I do not know psychology generally as good as a psych grad if that makes sense.

I would know little about interview technique, the history of psychology and little on anything but the few topics that I've an interest in.

That is the difference between a lay interest and an academic background in a topic.

Surely knowing the groundwork and basics would automatically give you a better understanding? For a lay person they might be able to describe what general relativity is about and what it means but they don't have a true understanding of it because they don't have the ground work. From a mathematical prospective they don't know why the theory is true. Would I be right in saying that to understand general relativity you need to understand the maths involved?

Sev

nesf wrote:

I get that a lot. It's no fun, means I kill thread half the time!

Thats ok, im sure theres lots of other things we disagree on.

How do you eat your cream egg? (rhetorical)

nesf

David19 wrote:

Surely knowing the groundwork and basics would automatically give you a better understanding? For a lay person they might be able to describe what general relativity is about and what it means but they don't have a true understanding of it because they don't have the ground work. From a mathematical prospective they don't know why the theory is true. Would I be right in saying that to understand general relativity you need to understand the maths involved?

Whats to stop a lay person who's mathematical from understanding the maths involved?

College isn't the only place to learn maths you know.

Son Goku

Yeah, you do.
Although General Relativity is fairly self-contained.

For instance, given an itnerest, Bernard F. Schutz's book would be enough to introduce somebody to General Relativity.

Without much groundwork beforehand. (Like a knowledge of Lagrangians)

nesf

Son Goku wrote:

What brings you to that conclusion?

I'm afraid the answer to this will forever be a mystery for he has been banned.

I'm sure the generations that follow us will ponder it though.

Son Goku

I'm afraid the answer to this will forever be a mystery for he has been banned.
I'm sure the generations that follow us will ponder it though.

lol.
A happy ending to a happy story.

nesf

As a side note, I had a lay interest in cryptology ages back and had a solid mathematical understanding of it.

But I've never done a course on the topic. I just picked up the maths as I went along, or if I didn't understand something I looked it up and figured it out.

Admittedly yes, not knowing much maths does make physics very hard to get your head around, but just because someone didn't do a maths heavy course in college does not mean they aren't good at it or unable to learn it.

If someone had a serious interest in General Relativity and wanted to understand it, they could teach themselves the small subset of mathematics thats used in it.

Like I said, niche subjects are easy to get deep with.

David19

Ah ok, I thought we were talking about a person who doesn't understand the maths i.e reads pop science books. Also, I wasn't sure if general relativity was fairly self contained as Son Goku put it.