Saturday, August 24, 2013 ... Français/Deutsch/Español/Česky/Japanese/Related posts from blogosphere

Imagining 10 dimensions

Peter F. sent me a link to this video, Imagining 10 dimensions.

It has 104 minutes but based on various hints and a quick selection, I believe it must be a pretty good one for an apparent amateur creator! Correct me if I am wrong but I hope you won't! ;-)

I hope that at least one more reader will find the required spare time to watch it.

Note that Imagining 10 dimensions is also a blog.

For others who are more busy, a homework problem: Where have you seen the background color under the Calabi-Yau manifold from the video at 1:39:06? ;-) It's actually an originally Mathematica animation that was redone with other options.

Add to Digg this Add to reddit

snail feedback (55) :

reader Dimension10 (Abhimanyu PS) said...

Is this post intended as a joke? Because from the various comments in the video, about Quantum Mechanics, especially, it's clear that that the poster is a crackpot.

reader Anonymous said...

The video starts out OK adding one dimension after the other. The fourth is time -- fine. The fifth, though, he says, it's what allows Everett's many worlds to coexist -- bummer, I stopped watching soon after that. The sixth, he says it's a phase space -- much better, but still misleading.

Personally, I am not fond of naive visualizations. Keep it somewhat abstract, you'll be fine. Higher dimensional spaces aren't as strange as some people would like you to believe. If you stockpile ten different liquids, you are dealing with a ten-dimensional (half) space. Fine, you don't live inside of it, but you can deal with it just fine on an intellectual or calculational level.

My point is, aside from being stupid in it's specifc content, the intention of the movie seems slightly misguided to me.

reader Michael said...

The video starts out OK adding one dimension after the other. The fourth is time -- fine. The fifth, though, he says, it's what allows Everett's many worlds to coexist -- bummer, I stopped watching soon after that. The sixth, he says it's a phase space -- much better, but still misleading.

Personally, I am not fond of naive visualizations. Keep it somewhat abstract, you'll be fine. Higher dimensional spaces aren't as strange as some people would like you to believe. If you stockpile ten different liquids, you are dealing with a ten-dimensional (half) space. Fine, you don't live inside of it, but you can deal with it just fine on an intellectual or calculational level.

My point is, aside from being stupid in it's specifc content, the intention of the movie seems slightly misguided to me.

reader Dimension10 (Abhimanyu PS) said...

"slightly" : ) +1.

reader Luboš Motl said...

It's likely. ;-) I haven't watched it.

reader Gene Day said...

As soon as it was stated that Everett’s “many worlds” is gaining wide acceptance I turned it off.

reader Luboš Motl said...

Thanks for the info, Gene! Sorry for having used you as a test rabbit. ;-)

Peter F. actually warned me against the many-worlds irritation!

reader Phil Jones said...

Meh, he's not claiming to be anything other than an artist. From his website: "Again, if someone is confused about whether I'm pretending to be a
physicist after all this, then I'm afraid you're just not paying
attention! I'm a composer, who has written a large number of songs and a
book, all built around a "new way of thinking about time and space"
which we're playing with in this project: and while there are many ideas
taken from mainstream physics and cosmology, this is better thought of
as a creative exploration that blends together science, philosophy,
spirituality, and metaphysics."

reader Dilaton said...

Hi Lumo,

nice technical theoretical physics TRF articles are never ever boring by definition ;-) !

They may be more or less high above my (and maybe other's) head on first sight sometimes, but I am always happy about seing such nice cutting edge physics nicely explained here. It contributes to keeping me excited about cool physics :-)

BTW I like Juan Maldacena from his very much fun FPP talk, which is uploaded on the FPP homepage ...

reader lucretius said...

I wanted to ask you a question about this last thing but there was no opportunity :-)

I think your proof of the second law of thermodynamics is very neat.
I agree that you reduced the issue of irreversibility to probability. What I am not fully convinced about, however, is that the "arrow of time" in probability does not derive from our experience or from the "psychological arrow of time".

Let's imagine that an intelligent being exists in some part of our universe which experiences time "backwards" - in other words, future before the past. It seems that such a being would compute conditional expectations etc. in the "opposite direction" to us. Would it then follow that using exactly your argument this intelligent being would arrive at the conclusion that entropy must always increase in its future (which is our past)?

Clearly such a being could never come in contact with us without producing a paradox so this might be an argument against the possibility of its existence. Still I have an unresolved doubt that the "arrow of time" in probability could be psychological and based on our experience and not an objective feature of the world as (perhaps) logic is.

reader Dilaton said...

High Dimension10,

it would be helpful it you could help
allerting good physicists on Physics SE about the discussion about a new
Physics site below the appropriate TRF post.
I have a big problem and am not able too, thanks to David Z:

What he has written to me is the following:

sent 2 hours ago


I'm writing in reference to your Physics Stack Exchange account:

Despite multiple warnings
against it, we've noticed that you continue to make inappropriate,
unfounded accusations against moderators and other site members. For
that reason, the moderators are suspending your account for 120 days.


David Z

Physics Stack Exchange moderator

Of course this is completely unfair and unjustified. The reasons could be the following:

Disagreement about the importance of the "SE model" versus the
community of contributing physicists in chat around this comment:

b) I tried to reopen a question against which David Z now has even posted in Meta about

c) The discussion about a new physics site in a Physics chatroom here

I am too active and too successful in counteracting the dictatorship of
some moderators (some mods are good and nice ones I highly appreciate)

Feel free to share this information on Physics Meta or anywhere else ...

reader Gene Day said...

What are you talking about? Is not the statistical view of time completely independent of psychology?
It’s nice that we have a subjective experience of the arrow of time that is consistent with its mathematical description but why does that mathematical description not stand on its own? It seems to me that to deny that is to deny science itself.

reader Dilaton said...

Hi Phil,

nice to see you again here ;-).

You will only here since on Physics SE David Z has killed me:

The reasons I suspect are explained to Dimension10 in a comment in the same thread ... :-/

Are you still interested in taking part in a new higher-level physics site?

Next week I'll be in hospital, but afterwards I will really try to set up a new physics site, I have found some competent help for technical issues in my family :-).

And since I can no really forget about Physics SE, I have some free time for it too ...

reader lucretius said...

The issue is, I think, best understood in terms of this hypothetical intelligent being that moves backwards in time. Such a being would have the same probability calculus but apply it backwards. This being would use Lubos' proof to opposite of the Second Law of Thermodynamics. If so, although the proof is itself is objective, its application depends on the perception of the "arrow of time".

reader Dimension10 (Abhimanyu PS) said...

Ok, sure.

It's definitely (b). David Zaslavasky sent you the message 7 h ago, and also the meta post 7 h ago.

(d) would also have affected, as there were surely other votes too.

reader Dilaton said...

These two comments could have contributed too, I posted in response to David Z still (!) bringing up new excuses to disagree with Manishearth's new book policy

reader Dilaton said...

We had 5 reopen votes, but for some reason only 4 were shown by the counter ...

reader Gordon said...

Hmmm, I was waiting for you to share Ron Maimon's fate--Your persistence in fighting Sauron's moderators was laudable, but some of the moderators have been "Gollumized" by their SE masters :) Other than checking your links above, I haven't scanned the site for a while, and have little interest in coming back to SE fwiw. MathOverflow isn't generally polluted by ignorance or overly controlling mods. I think because not everyone thinks they can do advanced math, while nearly everyone is an armchair "physicist", and SE, as a for=profit co. is interested in volume and demographics, not truth.

reader Dilaton said...

Yeah, I hope MathOverflow can keep up its nice high level and academic culture.
For this to work, the moderators and community have to be strict in keeping people who dont belong there out and by all means prevent that they start to gather high rep.

Maybe I will have to ask some slightly off topic questions on the Math sites, they have both a much nicer and more academic atmosphere and there are some physics tags too ... :-P

reader Eugene S said...

Would that hypothetical being die before it's born? (Being old, then youthful, then a toddler in the meantime.) Or should I rent the DVD? ;)

reader Luboš Motl said...

Dear Lucretius,

it *is* fair to say that the time-reversal asymmetry entering the probabilistic considerations *is* psychological - but that doesn't mean that this asymmetry doesn't affect our lives. It does. A great deal.

At any rate, these two logical arrows of time are inevitably aligned. It's also impossible to have the opposite arrows of time that co-exist in the same Universe because such a Universe would have closed time-like curves which lead to the usual inconsistencies.


reader Eugene S said...

Dear Dilaton, sorry to hear about that. Perhaps there is a silver lining in that cloud?

Good luck next week in the hospital! "They'll fix you. They fix everything."

reader Luboš Motl said...

Dear Dilaton, sorry to hear but I don't follow your arguments with David Z. or ManIsEarth etc. and I can't imagine what sensible these arguments could possibly be about.

Also, I don't realize that those people are affecting my life or their server's traffic in any readably negative way. I don't even know who they exactly are. If you told me they are string theory professors or grad students, I would be able to believe it.

The hysteria just doesn't make sense to me. So in my opinion, you should just calm down in those 120 days, as intended. Also, I don't believe that just by cutting the low-quality traffic, you create a better server. Such a server would have a vastly lower traffic, would be boring, and ultimately probably abandoned.

reader Luboš Motl said...

That's interesting, Gene, because we would always agree about these subjective/probabilities matters and I completely disagree with you here.

The probabilities in QM *have* to be interpreted subjectively for the usual reasons, that there is no objective reality outside the measurements and the propositions are given their truth values relatively to someone who knows/learns/measures them. Quantum statistical physics is just extending these probabilities to a broader type of ignorance and must be interpreted in the same way and classical statistical physics is just the limit of quantum statistical physics so the interpretation still has to be the same.

So all the psychological manifestations of the arrow of time clearly have the same origin as the arrow of time in probability - it's the logical arrow of time and it's subjective in nature. Of course that it isn't linked to some "special topics" that real-world psychologists like to talk about, like Freud, but it is psychological in the sense that it is linked with a subject's knowledge, perception, desires, expectations, and plans. The difference between memories and expectations *is* the very same difference as the difference between probabilities of microstates in the initial state and the final state. The latter is just a mathematical way to phrase the former and the concepts are inevitably subjective.

For the usual reasons, it doesn't prevent the people from developing common knowledge and objective science etc. etc. but the fundamental and only accurate interpretation has to be subjectivistic.

reader Dimension10 (Abhimanyu PS) said...

The first close/reopen vote is never shown.

reader Dimension10 (Abhimanyu PS) said...

I don't think he will. Don't forget that it was *him* who banned Ron Maimon.

Also, it seems that the "We will not discuss suspension reasons unless explicitly allowed by the user" has become "We will never discuss suspension reasons.". c.f. the replies to [this](

reader lucretius said...

From our point of view. From his point of view we die before we are born. Of course such a character in our universe (as Lubos pointed out) would create a closed loop.
The guy in the film is only ageing in the opposite direction but his experience of time is the same as our. But it seems to me that even so he is probably violating the Second Law of Thermodynamics (?)

reader Phil Jones said...

Gosh Dil, that's longer than Ron's ban was - what did you do - divulge some sensitive SE secrets to wikileaks? Yes, I'll be keeping my eye open for what you do with the physics site ideas. Hope all goes well with your hospital visit.

reader Dilaton said...

Thanks Phil for the nice words ;-)

Well I did just the usual disagreements with the mods, tried to reopen an wrongly closed question, talked with a nice TP student about starting a new site, and as Dimension10 said in a comment here probably the second whas the reason ...

I have become quite successfull in finding people who disagree with the bad political moderation too and trying to improve things, which in particular two mods dont like ...

I have just registered on Physics Forum under the name of my superpartner and asked a silliy cosmological test question... I want to see if I get a better response there than on Quora, where my questions (as Sebastian Schacher :-P) get mostly ignored ...

reader Dilaton said...

Thanks Eugene for these nice words :-)

I feel not that bad at present, but something has to be done for it to not potentially become bad ...

There's a good probability that it is mostly harmless but nasty.

reader Dilaton said...

Thanks for the nice words Lumo ... :-)

I have just registered at Physics Forum and started a test question ...

I hope my visit in the hospital will only be a few days, the doctors are quite optimistic that it is mostly harmless but something has to be done about it ...

So dont write too many nice cool physics posts while I'm away next week, such that I will have a change to catch up again after my time out ;-)

TRF and the nice people here will be a good comfort during recovery for me :-)

reader Dilaton said...

I neither forget nor forgive what Shog9 has done to Ron and the site by suspending him ...

But concerning other issues, he has proven more reasonable, more relaxed (then certain two Physics mods), and accessible, than I first thought and expected. This is why I asked him for help.

Yes I have seen this short chat discussion, you are free to copy-paste David Z s message there or anywhere ...

David Z is quite dishonest in denying that what you said in chat is true, it can be read in the suspension message ...

There was an ugly chat exchange two month ago with Manishearth

But there was absolutely no new warning that I did something wrong, apart from the suspension message. I replied to David Z the following

@David Z

Can we talk about this somehow, here in this thread or per mail?
This completely blindsided me, and I did not expect any suspension and
least of all such a long one. Manishearth's message you linked too is
more than two months old and there was no other (personal) message from a
moderator apart from the one I am responding too since this.

Yes, I often even strongly disagree with you or other people about
things, if I think they counteract the (re)formation of a nice rather
high-level academic in spirit community, and then I say so.
And I use my votes as I see fit (in my personal opinion) to improve the
level of the site and make it more attractive for good advanced students
and experts again. This may not always be in agreement with the current
And when I discuss with people about starting some kind of a Physics
Overflow (because I am not sure if the level of the site can be improved
again after all) of course I talk about things I think are not optimal
at present on Physics SE and that should be better or different on a new

But I did not know that these things are suspendable at all, and now
even for such a long time. All that I wanted in principle was to make
Physics SE a nice site for Academics, researchers, and students, as it
was intended in the original Area51 proposal and is still written down
in the About.

Being able to ask question here (and I sometimes liked to answer too)
and interacting with good nice knowledgeable people is very important
for me in the real world too, as I am trying to get into a new research
topic, which is not (yet) well represented at my institute. I can ask
nobody about certain questions and topics in the real world. This very
long suspension is quite devastating for my real life too.

So is there any way out of this? Can our personal differences be abridged somehow and this long suspension be lifted/shortend?

I can offer to stay completely out of any site political issues in
the future (I would then redirect all my efforts I used to put into
discussion, meta posts, etd into learning how to set up a site myself
for example) and use exclusively the mainpage (while neglecting chat and
Meta) and refrain from looking into the review queues and close/reopen
voting , flagging, and such if this is the only way that allows me to do
at least some physics on Physics SE.

I will probably not be much online next week, since I'll be in hospital and hopefully back home afterwards ... :-/

But I dont expcect him to reply, as he was online since I have written it and he did not ...

reader Dilaton said...

And as usually, the bureaucrats and politicians are again dominating this meta discussion too

instead of the real physicists, who have upvoted and voted to reopen, speaking up for this question and against the silly bureaucratic political rules there are too many of on Physics SE ... :-/

reader Dimension10 (Abhimanyu PS) said...

You're in a hospital in real life too? I thought only on Physics.SE...

reader Dilaton said...

Yep, I will have to go there tomorrow, and hopefully be back home after a few days

reader Dimension10 (Abhimanyu PS) said...

There's something really weird going on. Mostafa just realised in chat that Ron Maimon is suspended *again*, for a year.
This is just crazy.

reader Dimension10 (Abhimanyu PS) said...

Wait, what?! Because you're suspended, they don't display your vote? :

And, "The item is no longer reviewable."? There probably needs to be a migration path for these kinds of questions to Math Overflow.

reader Dilaton said...

Yep, I have just seen it ... The dominant mods have gone completely crazy and mad at Physics SE (I dont think that Qmechanic has anything to to with it)...
The "evil" is not the SE network itself, they are quite liberal as Shog9 said. The individual sites are quite free to choos their own way and culture, adapt the rules to the needs of the local community etc ...

This is way research-level sites as TP.SE, Math Overflow, and Theoretical Computer Science, can allow study material/reference and list questions if they want to. And they do because there is nothing wrong with lists of interesting high-level stuff and being able to ask about study material / references is needed by researchers and students anyway.

The evil are some of our own Physics mods ... :-/

So maybe it is really time to give up on Physics SE, the dominating people in power are banning good the good knowledgable people who are still left, such as Ron for next to nothing now :-(

reader Dilaton said...

David Z has locked the question, most probably because he wants it to be from community reopend, which would have happend soon if it not already had ...

On locked questions you can not vote, comment, flag, answer, etc, this has nothing to do with my suspension

David Z already did it with a plasma physics question that was an the verge to get community reopend. He is a good, big, and very efficient dictator ... :-/

And BTW Neo is banned for a year for no reason too !

Maybe you could give the OP of the Breakthrough question the advice to reask his question on Math Overflow somewhere else below his posts or where he has commented ... They will certainly not migrate it I fear. Such questions should be asked on Math Overflow right from the beginning...

reader Phil Jones said...

LOL@ Dilatino! Seems like a reasonable question. I guess it it is indeed BSM physics which gives rise to the inflaton but let's see what they answer (I know nothing about cosmology). BTW who is the guy called "Marcus" who does all the pro-LQG stuff in the BSM forum?

reader Dimension10 (Abhimanyu PS) said...

They may not be affecting the traffic to the server of Physics.SE in a negative way but are surely decreasing the quality of the site, and irrationally suspending.

By allowing pop-sci questions and even borderline crackpottery, they're only reducing the quality of the site by giving the impression that good questions aren't appreciated.

Furthermore, all sorts of trolling about string theory and completely wrong answers (e.g. Quantum Mechanics treats time as discrete, and similar nonsense), are accepted, e.g. this:


reader anony said...

At first I liked certain parts of the video, but after more reflection have issues with the fact that he uses time twice in his conceptualization, once for the fourth dimension, and again for the final dimension. I also didn't like his misuse and effective redefinition of phase space. The mixing of different concepts eventually departs from any notion of metric space, which is what we are referring to when we talk of physical spaces, so notion of distance is lost when we get to the many worlds interpretation of the 5th dimension, at least as used in the video. Although there is some notion of distance in the hilbert space that is the proper space to discuss many worlds, I don't think there is any proper sense of "distance" in the way many worlds is introduced in the video. In a proper physical space, if I can place the many worlds on a line, I should have some means of consistently indexing the distance between each world. I would be curious if there is one.

reader Luboš Motl said...

Dear Dilaton, it's OK but didn't we create a special threat exactly for these off-topic things not to be posted in threads like this one?

reader Luboš Motl said...

Thanks for your feedback - I would also be annoyed by someone who mixes general spaces with some dimension (phase space is OK, spiritual dimensions or general quantities in a graph would be worse) with the spaces where all the dimensions have the same character as the known ones so that one can define a metric on the whole space.

reader Dimension10 (Abhimanyu PS) said...

There is? Where? (Is it the discussion on old and new theoretical physics forums?).

reader Luboš Motl said...

Yup, that's what I meant.

reader Dilaton said...

Up to now I have no answer, my question just gets ignored there ... :-/

I have noted Marcus too, but I dont know who he really is. He seems to be an LQG theorist since he obviously knows much about it, knows the scene ect ...

People sometimes ask him how to get into the field and he is obviously able to advice them

reader anony said...

I also believe people are not connecting that our world is not purely defined by the simple geometry used in SR and GR. The reason they get mixed up is that they are trying to take a world that reflects infinite dimensional spaces and try to frame it in terms of naive geometry. So the author of the 10 dimension video, while good intentioned, is trying to link infinite dimensional spaces, like phase space, to simple spatial dimensions. I think the following video series is a better intro for people who are interested in understanding metric spaces. Still too technical for some, but it should be fine for undergrads,

reader Gordon said...

One thing I didn't like was how quickly some of the moderators were to call questions "philosophy"( which generally was a code word for anything that wasn't isomorphic with their views, or else had literary merit.) I could see Einstein, and particularly, Bohr having their questions quickly closed as "philosophy".
Since I am not professionally doing physics, I am not passionate about all this, as you are, but I do like finding and reading great sites and blogs of varying sorts.

reader NumCracker said...

Dear Lubos, is the usual geometric concept of dimension (hausdorff dimension) assumed by ST when one argues the theory lives in 10d? Or, this 10d can be understood as "generalized coordinates" in which the theory is embedded? For instance, would it be possible to alternatively formulate ST over a simplex defined in terms of 10 deficit angles (or other parameters) instead of 10 "usual" dimensions ? Thanks

reader Luboš Motl said...

Dear NumCracker, the Hausdorff dimension is useful for various fractals etc. but I don't think that it's any relevant in string theory - or any other realistic enough theory in physics. It just doesn't work like that. We need differential manifolds as spacetimes, not fractals, to define fields etc. So the dimensions are just the scalar fields in a world volume...

I don't understand what sort of "other" coordinates you mean. You may of course redefine the coordinates by any diffeomorphism, that's how GR and all of its generalizations work. But you may mean something different.

reader lucretius said...

As Lubos already pointed out, Hausdorff dimension is a very general concept applicable to very complicated spaces where other definitions do not apply. It coincides with other common concepts of dimension (e.g. Lebesgue covering dimension, manifold dimension, the dimension of a variety etc.) when they are defined but in the case of spaces considered in algebraic and differential topology, differential and algebraic geometry and most areas of physics Hausdorff dimension is an over-kill.

As far as I know the most general types of topological spaces that appear in sting theory are orbifolds (which are the subject of one of today's Lubos' posts). These are objects that are more general than manifolds (locally they look like quotients of manifolds by actions of finite groups) so they inherit a natural concept of dimension from manifolds.

reader NumCracker said...

Dear Lubos, I was just thinking about how to define ST over a non-differentiable manifold (if it can be done) ... as for instance, a simplicial one ... in such situation the embedding space would be an R^10 space but the "effective" dimension (hausdorff) of the theory would "seem" lower. For instance, it seems me that in IKKT ST-matrix model the concept of space dimension may be faced as an "emerging" one ... but I really don't understand how the critical dimensionality (10d) is uniquely defined in such case =(

reader lucretius said...

Do you mean a PL (piecewise linear) manifold? The concept of "simplicial manifold" is ambiguous - it can mean several different things (most often a simplicial object in the category of smooth manifolds - which does not seem to be suitable here). I have no idea what can be meant by an ST over a PL-manifold - I will leave this to Lubos ;-)

reader Dimension10 (Abhimanyu PS) said...

I think I had seen Marcus criticising string theory baselessly oonce.

Though he othterwiyse seems like a nice person.