Science String Theory

[old.Tohtori]

Toht - have you ever read any Charles Stross? His blog and his books that deal with post-Singularity humanity seem to me that they'd strike a chord with you. Incidentally he's the guy that convinced me that it's not only possible, but incredibly likely that we all exist in a computer simulation! Think Tamagotchi or The Sims instead of The Matrix.

HAven't read any, but sounds similar to mindset. I sometime ago thought up of an idea that we are all lhigh power superbeings, but earth is a simulation that serves as a prison. You're wiped of your memories as superbeing, then server your time and are left with the memory of the horrible life as a meatsack. Sentence ofcourse being the lifespan you have, giving a lovely link to "children are innocent"

 

[opticle]

Just because we can only perceive 3 dimensions (4...sort of...anyway) doesn't mean that there aren't others. Since we can perceive them, it makes sense that their "interface" with bog-standard 4-dimensional space-time would be small (or even non-existent).

Isn't "small" still defined by the other 3 dimensions?

I don't want to be a pedant and I don't dispute the likelihood of all these other dimensions (I'm sure there are), I genuinely want to understand what the hell people mean when they say these extra dimensions exist and could be curled up very small. Most books fail to really explain that and simply refer to a diagram of a teeny sphere, the concept of which I'm pretty sure I understood already. Then they go on about ants walking around toruses (?tori) for a while and the chapter ends.

My impression of dimensions (at least the 3/4 I know) is that I thought they permeate everything, everywhere - or rather, they define the nature of reality around us.

Surely like the other dimensions, these extra ones must be everywhere in reality ? How can they be curled up small ?

What do you mean by interface ? Why can't they be interfacing with everything, everywhere - only we can't detect it ?

Obviously, trying to explain things like this is bloody difficult, because human brains can only perceive and therefore imagine in 3(4) dimensions

 

[Zarjazz]

The reason the theoreticians add all these extra dimensions is because they make the maths work. That's often a strong case that a theory has some kind of basis upon reality.

Then they have to explain why we have never actually observed them, hence the topological arguments about "curled up dimensions".

Think of it this way. A cube with a rolled up dimension would look just like a square. Expand that to higher dimensions and more curled up dimensions and all we observe is the 3D space around us.

 

[opticle]

A cube with a rolled up dimension would look just like a square.

I like that.

But why does the dimension have to be rolled up ? rolled up where ? Why can't it just be "not visible and possible to interact with" ?

Or is this what you mean in your second point, that it's all just semantics and these dimensions are everywhere ?

Which I would like, but sometimes books and magazines go and give actual sizes, which just baffles the hell out of me:
"He supposed that the fifth dimension is not like the others, but instead is curled up into a circle that is too small to see...This is how Klein envisaged Kaluza's five dimensional universe and his calculations even showed how small the extra dimensions should be curled up. At 10 to the -35 metres across, the fifth dimension would be too small to probe even with the most powerful particle accelerators...hence we have the impression that we live in a four dimensional world."

This tiny circle.. is there only one, or lots, or wtf ?

They were using that to explain "Why can't we see extra dimensions?"

Can you please tell me that I can be content in thinking all that is bull**** unnecessary over-complication ?

Extra dimensions for gravity, etc. seem like pretty straightforward ideas without all that odd circles and size stuff..

 

[Roo Stercogburn]

Dr. Sheldon Cooper works on String Theory. Therefore it must be awesome.



In other news, rather impressed with how easy it is to embed compared to previous FH forums

 

[Zarjazz]

But why does the dimension have to be rolled up ? rolled up where ? Why can't it just be "not visible and possible to interact with" ?

The logic goes something like this: "Our new theories only work if there are more than 4 dimensions. Great. So why the f*** can't we see them?"

Or is this what you mean in your second point, that it's all just semantics and these dimensions are everywhere ?

Not really but yes. A dimension has to exist everywhere. That's kind of a definition of it

Which I would like, but sometimes books and magazines go and give actual sizes, which just baffles the hell out of me:
"He supposed that the fifth dimension is not like the others, but instead is curled up into a circle that is too small to see...This is how Klein envisaged Kaluza's five dimensional universe and his calculations even showed how small the extra dimensions should be curled up. At 10 to the -35 metres across, the fifth dimension would be too small to probe even with the most powerful particle accelerators...hence we have the impression that we live in a four dimensional world."

This tiny circle.. is there only one, or lots, or wtf ?

They were using that to explain "Why can't we see extra dimensions?"

Okay, now it does get complicated!

A dimension does not have to be "flat" and stretch out to infinity (like the good old X,Y,Z axis you know and love) Simplest example I can think of is a sphere, such as Earth. You can travel in X or Y and eventually return to the same point. Now instead of a sphere instead think of an infinitely long tube (or those torus pictures you've seen that only have 1 surface). Now shrink it until it's really really really tiny.Then imagine that as one of the axis of a hypercube ...

The 10^-35 figure you've seen comes from the fact that if the dimension was larger than that we should have observed it in experiments by now.

Can you please tell me that I can be content in thinking all that is bull**** unnecessary over-complication ?

Extra dimensions for gravity, etc. seem like pretty straightforward ideas without all that odd circles and size stuff..

Yes it's complicated and most of the theories will turn out to be bullsh*t. While extra dimensions sound cool we still have zero evidence to show they exist.

 

[opticle]

A dimension has to exist everywhere. That's kind of a definition of it

The 10^-35 figure you've seen comes from the fact that if the dimension was larger than that we should have observed it in experiments by now.

But if it's everywhere, how can it be so small ? And how can a dimension have dimensions in other dimensions ?

Also, ty for continuing to try to explain to my teeny brain

edit: I am going to read this: http://www.sjbaker.org/wiki/index.php?title=Extra_Dimensions_in_String_Theory_explained

 

[opticle]

Cursed edit time limit.

I think I get it

So.. We're assuming dimensions don't necessarily have to be infinitely large ?

And that business to do with dimensions having dimensions in other dimensions that was upsetting me so much is actually because I was misunderstanding articles when they gave a size, and what they're actually doing is using a measurement of distance (metres, i.e. size, doh) to describe the non-infinite nature of these dimensions.. which is perfectly ok because we use metres to measure x, y and z, so why can't z+1 have a look in ?

Braingasm. I think I need a lie down.

 

[Raven]

Just because we can only perceive 3 dimensions (4...sort of...anyway) doesn't mean that there aren't others. Since we can perceive them, it makes sense that their "interface" with bog-standard 4-dimensional space-time would be small (or even non-existent). Science has precisely one thing in common with religion; it involves telling stories. The difference is that science is constantly writing new stories and updating or throwing away old ones that proved flawed. Religion wrote one load of stories thousands of years ago and these are "interpreted" to fit in with whatever scientific or moral ideas are currently accepted in a given society.

Another way to look at it is model-making. In Science we make a model universe, basing it on what we observe. As we can observe more and as our tools improve, we can make a better model. Look at the movement of celestial bodies from geocentric to Newtonian Heliocentric via nested spheres, weird geometric shapes and epicycles. At each stage we have a model that better describes the observable universe and allows us to make better predictions.

Someone previously said that without religion we wouldn't be here and I'm not sure if this was meant to be a joke or not. I expect that without religion, we might not have certain taboos such as polygamy and homosexuality, which would probably not even be remarked upon. I'd like to think that we could have come to the conclusion that things like murder and rape are bad without needing divine inspiration. I'd argue that without science, we definitely wouldn't be here...more importantly without the desire to write and improve stories, explore the world around us and work out how things work we wouldn't be here.

String Theory (or any controversial or currently unfalsifiable premise) encourages thinking, the asking of questions, the development of testable hypotheses and, ultimately, the writing of new stories or the throwing away of old ones. Religion denies progress; if we assume "God did it" then why look deeper?

I can highly recommend Marcus Chown's book The Never-Ending Days of Being Dead which discusses some of the more "out there" concepts of maths and cosmology in an engaging and accessible way. Want to know more about Omega? Wolfram's theories on computational complexity? Just a really good explanation of the Halting Problem and it's effects on current scientific thinking? It's a really, really excellent read.

My first neo-FH "like"

Congratulations!

 

[Shagrat]

I post a thread and go to LegoLand for 2 days and come back to find the thread back on track

Fascinated by the whole "arena" of theoretical science, and how someone can have such a grasp as to theorise something that is only proved as being correct many years later (like in the case of neutrino's). As we peer further and further into the universe around us (both on a micro and macro scale) we discover more and more.

At the moment, we're down to the theoretical particle level, and of the 16 particles to make that work, we're still missing concrete evidence of one (if im right) but who's to say that when we've cracked that its not the last level to pass through.

Sat here at my pc ive got neutrino's zipping around and through me, an amazing (and also slightly scary) feeling