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Bikerdude
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This is how I learned it (a while ago, I might get some details wrong.)

The static electric charge generated by the cloud water particles builds up, (just like rubbing a rug with a balloon) the rubbing is pulling off electrons to pool up and creating a negative charged soup, and the ground under it has their electrons streaming away from the repulsion so you get a patch of net positive charge (also pulling the electron soup in the cloud towards the bottom surface and wanting to go to the ground)... Then there's a conducting constant for air (like all materials), and when the static charge gets high enough it goes over that constant the electrons will start streaming through channels of air. That raises the air molecule's temperature so high and the electrons are peeled off them that it heats into into plasma and glows, which is what the actual "lightening" is.

 

Then when one path hits the ground, which is net positive in a patch but globally neutral, all the built up negative charge floods down that path to restore neutrality to the clouds and ground region. I mean it's the path of least resistance to neutrality, so the preferred path. But then the flood ends up carrying more electrons down and now the ground will be negatively over-charged, so the electrons flood back *up* to the clouds, which does the same thing, so that "flashing" that you see is actually the electrons flooding up and down the path very quickly back and forth many times, IIRC it can be a few hundred times very quickly before it gets balanced back out to neutrality. It's the same thing that happens with a capacitor (two conducting plates facing each other), you add a little charge to one side and you'll see the sparks chattering back and forth for a long time.

What do you see when you turn out the light? I can't tell you but I know that it's mine.

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This is how I learned it (a while ago, I might get some details wrong.)

The static electric charge generated by the cloud water particles builds up, (just like rubbing a rug with a balloon) the rubbing is pulling off electrons to pool up and creating a negative charged soup, and the ground under it has their electrons streaming away from the repulsion so you get a patch of net positive charge (also pulling the electron soup in the cloud towards the bottom surface and wanting to go to the ground)... Then there's a conducting constant for air (like all materials), and when the static charge gets high enough it goes over that constant the electrons will start streaming through channels of air. That raises the air molecule's temperature so high and the electrons are peeled off them that it heats into into plasma and glows, which is what the actual "lightening" is.

 

Then when one path hits the ground, which is net positive in a patch but globally neutral, all the built up negative charge floods down that path to restore neutrality to the clouds and ground region. I mean it's the path of least resistance to neutrality, so the preferred path. But then the flood ends up carrying more electrons down and now the ground will be negatively over-charged, so the electrons flood back *up* to the clouds, which does the same thing, so that "flashing" that you see is actually the electrons flooding up and down the path very quickly back and forth many times, IIRC it can be a few hundred times very quickly before it gets balanced back out to neutrality. It's the same thing that happens with a capacitor (two conducting plates facing each other), you add a little charge to one side and you'll see the sparks chattering back and forth for a long time.

 

In other words: *BzzzzzzzztrcrackleddrrBOOMfizzlesmoke*

"The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." -- George Bernard Shaw (1856 - 1950)

 

"Remember: If the game lets you do it, it's not cheating." -- Xarax

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I got a Logitech wireless mouse. Its a damn fine piece of engineering really. The receiver is tiny, the battery lasts REALLY long. The only way to improve it would be to use the monitor to charge it like this when in close range.

 

http://www.youtube.com/watch?v=r1UT4NuygmQ

Edited by lost_soul

--- War does not decide who is right, war decides who is left.

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I think if I had taken a different path I might have gone into theoretical physics. I'm a junkie for textbooks & video courses on it. One thing I like about math & physics, you can prove things... Even if you wonder whether it's saying something about the world, you at least know when you got the math right. You can't say that much about law and politics, what I normally do.

 

I just watched Susskind's course on

, geared for undergrads. I liked it a lot, but I had some questions. Do you know about the topic? Would you mind if I ask you some basic questions, would you be up to answering them to help me understand it?

What do you see when you turn out the light? I can't tell you but I know that it's mine.

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I think if I had taken a different path I might have gone into theoretical physics. I'm a junkie for textbooks & video courses on it. One thing I like about math & physics, you can prove things... Even if you wonder whether it's saying something about the world, you at least know when you got the math right. You can't say that much about law and politics, what I normally do.

 

I just watched Susskind's course on

, geared for undergrads. I liked it a lot, but I had some questions. Do you know about the topic? Would you mind if I ask you some basic questions, would you be up to answering them to help me understand it?

 

I never studied string theory so I probably couldn't answer any of your questions. It's one of the subjects I'm interested for the doctoral though.

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I think if I had taken a different path I might have gone into theoretical physics. I'm a junkie for textbooks & video courses on it. One thing I like about math & physics, you can prove things... Even if you wonder whether it's saying something about the world, you at least know when you got the math right. You can't say that much about law and politics, what I normally do.

 

I just watched Susskind's course on

, geared for undergrads. I liked it a lot, but I had some questions. Do you know about the topic? Would you mind if I ask you some basic questions, would you be up to answering them to help me understand it?

 

Are these your christmas wishes? :D I only have a rough understanding of the topic, but I'm at least interrested in your questions. So if you still like to, ask. ^_^

FM's: Builder Roads, Old Habits, Old Habits Rebuild

Mapping and Scripting: Apples and Peaches

Sculptris Models and Tutorials: Obsttortes Models

My wiki articles: Obstipedia

Texture Blending in DR: DR ASE Blend Exporter

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Oops I forgot about this thread & a lot of my string theory questions. Well even if no one can answer them, it might still be interesting to post the questions for their own sake. It's a fun subject to read about, even aside from how relatively undeveloped it is as a consistent theory (there are like a dozen different ways to make an electron apparently, but they can't all be right at the same time), you get a natural tour through all the other established theories along the ride. But also it's hard not to see the elegance in solutions naturally coming out of basic features, like the boundary conditions of the string, or its tension. When it comes to the right answer, there's just something satisfying about it, especially when it comes to the right answer surprisingly; like you can really see it coming from the features of the theory and not handwaving & a theorist putting it there by fiat (which is how I felt Loop Quantum Gravity was handling some things, even though I initially liked it more.).

 

Here are the questions I had written down from the closed string lecture.

 

(1) One question was about the concept of spin. So closed strings in their lowest energy state have waves of 1-quantized energy, but wobbling in opposite directions, which makes them "spin 2", the basic feature of a graviton. But I'd thought about spin in terms of (among other things) angular momentum, so e.g. if the particle interacted with another one, it could transfer units of angular momentum and up its spin state in quantized units.* It just seems like if you had the same energy going in opposite directions, the two would cancel each other & you'd have an overall momentum of zero -- if it interacted with another object, it'd contribute zero angular momentum to it. Anyway, I felt like I was missing something with the idea of spin, how even waves in opposite directions with each other still counts as spin-2. (Susskind warned against considering them "real world directions" though; it was a more abstract directedness on a string, like drawing little arrows on its pieces; I don't know if that's part of what's confusing me though.)

 

*Footnote, As I understand it, the larger & more complex an object is, the more spin states it has at closer energies, so if you were spinning up like a basketball, it's angular momentum would still be going up in quantized units, but they're so close together it's almost indistinguishable. Whereas for a fundamental particle, one feature of being more "fundamental" is that the next state is a very significant leap.

 

(2) I had a question about what job the Level Constraint was doing, or a way to visualize or conceptualize it.

So the Level Constraint says there must be rotation symmetry for strings, which means waves on a string must be matched by equal energy waves in the opposite direction. I wanted to get an image of what this means.

(i) First I was wondering what the analog might be for a classical string (which is how some other concepts were introduced). I can imagine a classical string with a wave wobbling in only 1 direction, and there isn't any contradiction. So I wondered what about the quantized string in a lightcone frame (so still classical in the 2D perpendicular frame according to Susskind) changed that. And then I thought the issue might have something to do with the fact quantized strings don't have any "preferred point", you have to take them as a holistic whole in energy states, but you can't pick out any individual point or wobble & name it. This was how Ziebach introduced strings in his textbook, saying we can't literally measure points on the string wobbling up and down, only an overall action or pattern on the whole string. I'm thinking the Level Constraint is in that neighborhood, but I'm still at a loss about why, if you have a wobble in one direction, something in the math is forcing a rotationally symmetrical wave in the opposite. It can still be quantized with just the one wave, can't it?

 

(3) A third issue I had wasn't so much a question as an observation about the fluidity string theory has between reductionism and constructivism. I've seen Susskind make a point in three different lectures how fundamental physics has, for quite a while now, softened up on what's "fundamental", and he loves these examples where "simple" objects morph into "complex" objects, and "complex" objects morph into "simple" objects, to the point where you lose any foundation for saying what's really at the base... From some viewpoints X's are made up of Y's, tweak things around and you'll find Y's made out of X's... (His typical example was a electron & magnetic monopole. In one context the electron is fundamental & the MM is massive & acts like a complex object. In another context, the MM is small & fundamental-like and the electron acts like a massive & complex object in a flurry of virtual particles.) Are strings made up of wound-up branes, or are branes made up of strings stuck together? It's consistent both ways, it seems. Another thing was the symmetries Witten found with M-Theory -- when you curl up space small enough, from the string's pov it "looks like" it's expanding as a different kind of string, so there's not any fact of the matter what shape the "real" space is since all the interactions are agnostic on it. There were a few other examples.

 

What's cool to think about is this idea that the most basic elements of reality aren't "things" that "act" on each other, where things are made out of smaller things until you get to the smallest ones carrying all the load (reductionism), like we used to think, or even the "turtles all the way down" claim which some thought, but it seems even more radical than that... that down there aren't things but processes, and the processes can shift depending on the context, so it doesn't make sense anymore to talk about what's more fundamental, or what to reduce things to. We may have hit an area where it doesn't make sense to reduce because there's nothing left to reduce to. There's just processes that morph into other kinds of processes and vice versa. Anyway there are indications in the structure of the theory coming out in that direction. It's interesting to think about for me anyway.

 

I'm also very curious about the Holographic Principle and the shift in emphasis from particles interacting in space to transactions of information communicated, and was interested after reading a couple of books that talked about it (Susskind's book on the Black Hole War between him with Hawkings being one), but that's another thing.

What do you see when you turn out the light? I can't tell you but I know that it's mine.

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(there are like a dozen different ways to make an electron apparently, but they can't all be right at the same time)

Nature chooses one description when observing her by throwing two dices. If she roll doubles she kills a kitten.

 

(1) A spin is not exactly the same as a spin of "big" objects. Whilst in the latter case it has something to do with mass or is an effect caused by mass and therefore giving the object kinetic energy, the spin you mean here is a bit more generally I think. It's also fixed IMHO.

What's cool to think about is this idea that the most basic elements of reality aren't "things" that "act" on each other, where things are made out of smaller things until you get to the smallest ones carrying all the load (reductionism), like we used to think, or even the "turtles all the way down" claim which some thought, but it seems even more radical than that... that down there aren't things but processes, and the processes can shift depending on the context, so it doesn't make sense anymore to talk about what's more fundamental, or what to reduce things to. We may have hit an area where it doesn't make sense to reduce because there's nothing left to reduce to. There's just processes that morph into other kinds of processes and vice versa. Anyway there are indications in the structure of the theory coming out in that direction. It's interesting to think about for me anyway.

Maybe an overall statement to the string theory: I'm not very deep into physics but I'm not sure how useful a theory is, that builds the world out of little strings (which we cannot measure IIRC, at least not very exactly due to Heisenberg, but I may be wrong) and requires the use of additional dimensions (which cannot be measured, too).

 

I'm not sure what to think about a science that goes more and more into the sci-fi direction but didn't even solve its fundamental problems. You may ask a physician what time is for example. It is like the quantum theory and Schrödinger's cat. Maybe it's just an effect of the easened articles I've read in science magazines, but what has a model describing reality to do with reality, except that it is describing it.

 

It is like you're rolling a dice and think the side showing upwards is not decided yet until you actualy look at it.

 

What I'm trying to say is: the string theory is a model, like quantum mechanics or the classical continuum mechanics. They do not necessary have anything to do with reality, except the fact that they may be quite useful for describing it approximately. So any interesting or unusual effects deriving from them can also be a product of the unusual preliminaries you put inside them.

 

... I may be wrong, anyways

FM's: Builder Roads, Old Habits, Old Habits Rebuild

Mapping and Scripting: Apples and Peaches

Sculptris Models and Tutorials: Obsttortes Models

My wiki articles: Obstipedia

Texture Blending in DR: DR ASE Blend Exporter

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Re: spin, by "fixed" I think you mean quantized, yes. It spins with a set, discrete quantized energy, and spinning it up would be like blinking it from one state to the next without going through the intermediate steps (quantum leap) in the weird way most QM works ... although it really does transfer angular momentum that gets other things rotating about a center, so there's still a spinning-ness to it. And, yes, it's definitely not like the way we think of a big object classically spinning in space (actually he went on to explain it is like big objects too, but not in the way you were talking about, not classically, because even big objects spin in discrete quanta, it's just so slight we don't notice it).

 

String Theory is different from QM & classic mechanics in the big way that there's currently no independent experimental evidence (AFAIK) that uniquely verifies the theory. All experiments are still consistent with the Standard Model, which is the state of art of QM. The one discovery that would weigh in its favor though still not uniquely prove it, super symmetry, hasn't been discovered (and some experiments are cutting down its options to exist). The lectures did give some sense that we're talking about processes that are acting string-like rather than talking about literal strings. He said (IIRC) you could also describe it as flux-lines of chained particles and the math is the same. So that's a sense that, yeah, we're not talking about a thing that's really down there that we can identify, but how to model the processes that have to be going on to get the world we observe.

 

The beauty of it from what I've gotten from the lectures and books wasn't it being proven or talking about real things, but that it explains everything so naturally from such simple elements in such a surprising but satisfying way. People had a problem working gravity into QM, and string theory requires it (it's the first state of a closed string, which must always exist. You couldn't get rid of it if you wanted to), and the other particles fall out in that kind of natural way: a photon is a the first state of an open string. Fermions like quarks are trickier; you have to put little widgets on them so they can't be in the same place at the same time, but then they fall out naturally from there. Tie an open string's ends to a brane and you have an electron (IIRC). String vibration is it's energy/mass, spin is spin, momentum (in a particular dimension) is charge (also how it winds around space, but don't worry about that), particle interactions are strings combining & parting into new strings when they touch (so you see how mass, spin, and charge are naturally conserved). People stumble into insights into all sorts of fields they didn't know they were looking for because they just spill right out of the theory, which is a sign it's definitely on to something going on in the real world. Also because it can explain things the Standard Model can't, like tiny black holes & dark matter.

 

If you're at all interested, watch those lectures I posted. Susskind is such a good teacher. He knows how to explain even the most complex stuff in a simple way that makes sense.

What do you see when you turn out the light? I can't tell you but I know that it's mine.

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  • 2 weeks later...
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LOL Classic :D

"The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." -- George Bernard Shaw (1856 - 1950)

 

"Remember: If the game lets you do it, it's not cheating." -- Xarax

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"The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." -- George Bernard Shaw (1856 - 1950)

 

"Remember: If the game lets you do it, it's not cheating." -- Xarax

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  • 2 weeks later...

Funny I was just watching C64 demos coincidentally. Somebody posted a video on reverse engineering the 6502 chip (used in the C64 among others) on the TTLG FB group, and it got me on a whole romp through videos on the homebrew scene.

 

What you can appreciate these days is how much they can do with so little.

What do you see when you turn out the light? I can't tell you but I know that it's mine.

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The abundance of this type of videos is startling. Is there an 'entertainment' business based on filming staged office rages? How is it fun to see a fit of violence against a poor computer, office machine or colleagues?

 

Or there is alarmingly large amount of surveillance cameras in people's work places, monitoring people to see if they work at full performance at all times? Or there are scarily unstable people working in such offices? Or ordinary people are pushed to the brink of insanity in horrible working conditions?

 

Or an arbitrary mixture of all the elements?

Clipper

-The mapper's best friend.

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