I am at the limit of my comprehension, and am frusterated

I have finally reached the point where my attempts to know and understand are thwarted by my lack of education and possibly raw intelligence. I never took a physics class. Or a real chemistry class. Neither were required of my in high school so I took biology related classes. And in college, neither are they required for my major (psychology). The closest I got here was the many courses on psychopharmacology, all of which that I can take at a pre-graduate level, I have.

Consequently I find myself stymied at eveyr turn in my independent quest to understand the universe.

Most people I know are unaware that a Bose Einstein Condensate is a thing. I am, but I cannot comprehend what thing it is. A blob of very very dense matter colder than most anything else in the universe. But what ARE THEY? I cannot find pictures (only density graphics) so they are either too small for microscopes or the method for containing them eliminates such observation. Furthermore they seem to no longer be separate atoms, which confounds me. Exactly how dense are they, and why haven’t they turned into neutrons if they are so dense they cease to be individual particles?

I run into similar problems with light. In astronomy class it was a wave, a wave that carried its properties with it in the form of its wavelength. This could be observed clearly in red-shifting and in the very very long wavelengths of the cosmic background radiation, which has been mapped into digital images that make sense when I look at them.

But then I look up quantum mechanics and light isn’t a wave anymore, it’s a particle. Of course, you cant observe any of these subatomic particles in quantum mechanics, because hitting them with electrons would change them. So no pictures here. And if it is matter, does a single photon still have a wavelength? If so then how? And I hear they have no mass, so why are people trying to build solar sails? If something has no mass how does it impart kinetic energy? If it has no mass how does is have a distinct bounded form, without which it wouldn’t be a particle, it would be a ray (a zero-space line through reality) or a wave.

Or entropy. If energy can be derived from a vacuum, how is it that the usable energy of the universe if finite? Couldn’t we just pull more from the false vacuum of space-time? And since all matter in the universe pulls all other matter (and time, which is another thing I cant comprehend. How is time a physical thing, affected by gravity?) why cant we, in the many billions of years left before the universe dies, just clump lots and lots of galaxies together, distorting space-time until we can collect all reachable energy and, ideally, store it in higher physical dimensions?

And, also, if neutrinos are particles with mass (a very very small amount) why don’t they just clump together via the aforementioned attraction of all matter to all other matter, until they become macroscopic? And how come light doesn’t spontaneously form laser-like beams, since light can be affected by gravity?

If I ask these questions online, I am ignored, or given answers in the form of mathematical equations, as opposed to English. If I am given English, it contradicts what else I have heard, like someone telling my photons DON’T have a size, despite being particles, and focused beams of light having a size.

Worse yet, becoming initiated would require great wealth. College courses, or private tutors. Even then, I seem to be asking questions at a level that requires true wealth. The one book I located on the Casimir Effect (spontaneous force between two plates in a vacuum) costs hundreds of dollars.

Are their any cheap alternatives, or some way of training myself so I can answer these questions? Do mentors exist that can tach me the fundamentals needed to grasp these concepts?

And, perhaps most importantly, is anyone else out there having issues like me? Stymied after decades of knowing or easily learning all I want, and, unlike many people I know, unwilling to accept "you cant learn this" as an answer?

While the breath's in his mouth, he must bear without fail, / In the Name of the Empress, the Overland Mail.

Uh... maybe I got lucky with an initially crappy Primary education, or something. I learned long ago that some holes can't get filled, so fill what you can and don't worry. You'd be amazed what you can trick people you know.

Works for me.

• Light is particles. But particles are waves. From what I remember, particles are not round spheres like in the classical sense, but wave packets formed by superposition of waves.

• Because of the mass-energy equivalence, a massless particle still can have kinetic energy and momentum. See p = h/λ.

• I'm pretty sure entropy is not energy. And I don't think, according to current first law of thermodynamics, that you can just draw energy without limit.

• Neutrinos and other particles have such little mass that gravitational attraction is vastly overshadowed by other interactions caused by their high energy. That's why quantum physicists in the 20th century largely ignored relativity, after making such a big deal about it. It's pretty ironic.

I tend to look up the surface information on sites and books, and if I'm really interested, I might delve in deeper and try out the equations (well, I should , but that's what I would do if I really wanted to get to it). So I guess you should see if you're really interested in this, do some recreational research and try to understand it.

"And, perhaps most importantly, is anyone else out there having issues like me? Stymied after decades of knowing or easily learning all I want, and, unlike many people I know, unwilling to accept "you cant learn this" as an answer? "

Of course. I have physical/metaphysical questions and curiosities too. For instance: is wave really a physical entity, much like matter, or is it merely a description of a phenomenon where energy is propagated?

And when I find that I find nearly 0 answers to these curiosities, I get surprised. I try to find a place where I can properly ask questions and learn some answers.

Now using Trivialis handle.

There's like a bunch of different topics there. I'll try to take them as you've mentioned them.

• Bose Einstein Condensate: I'm completely clueless on this one.
• Light waves/particles: This is actually a thing called wave/particle duality, which refers to the fact that light can be described both as a wave and as a particle. It's completely counterintuitive, but light is simultaneously both. A light particle is called a photon; it has no mass, but it does have energy. Essentially, you treat light as whichever is more useful for whatever you're talking about; in astrophysics, light gets treated as a wave, but in quantum physics, it's treated as a particle.
• Entropy: entropy is simply the name for the law of thermodynamics saying that energy in a system always decreases. You can't get more energy out of a system than you put in. In fact, you can't even get the same amount out that you put in — you always lose some. That's entropy.
• Vacuum energy: I'm fairly clueless on this one too.
• Neutrinos: Neutrinos, like all subatomic particles, have basically no mass. As such, gravity has essentially no effect on them compared to the other three fundamental forces (electromagnetic force, strong nuclear force, and weak nuclear force). The fact that they don't bind together due to gravity isn't unique to them; basically all matter first binds together due to the other three forces, so that gravity only comes into play on the macro-scale. Neutrinos, though, pretty much don't interact with other matter (like, "flying through a light year's thickness of lead without interacting with any lead particles" sort of non-interaction), so they never get to macro-scale in the first place.

edited 16th May '12 2:34:21 PM by NativeJovian

Really from Jupiter, but not an alien.

Do the math. Er...

Apparently, you want to understand the universe; this is an awesome goal, and you should not let the complexity, or your own skill compared to others, discourage you. However, there are two things you should know:

1. The language of the universe is, almost literally, mathematics. (To the point where we "discovered" antimatter in the maths before we found evidence of it in reality.) At the most fundamental level, the properties of objects are tied directly to the mathematical properties of the equations and structures which describe them. (However, before anyone navel-gazes about this, it's a chicken-and-egg situation.) Any English description will lose detail, and will almost certainly involve comparing the math objects with more familiar, but not quite identical experience. A major example of this is the wave-particle duality; it appears because there is no familiar example of an object that has both wavelength and the atomic behaviour of quantum particles. A more correct, but far less intuitive idea is that subatomic... things are neither waves or particles; they're approximately similar to a wave at low energies, and approximately similar to particles at high energies. "High," "low," and how "approximately" this is is very context-dependent, which is why you need the maths to give you precise answers.

2. However, math need not be hard*
   at least, if you have access to Wikipedia
   , nor scary. Winston's line "2+2=4. All else follows," is a very apt description%
   So what if he's talking about something completely different?
   - everything is built out of smaller and simpler things, until you eventually get down to the integers. Learning it is a bit like the later stages of learning how to read - once you've got up to a certain level, you can understand when people describe new structures and concepts. However, it's very likely that you're already there.

Almost certainly, but they will be expensive. However, this forum is quite knowledgeable, and our knowledge is free, albeit scatter-gun, less reliable and less timely than someone who's formally trained. (If you want more coherent, but more limited answers, feel free to drop me a PM)

However, as mentioned, a lot of this depends on how comfortable you are with maths, so it'd be very useful if you told us what you're math education's been like.

edited 16th May '12 4:22:50 PM by Yej

Da Rules excuse all the inaccuracy in the world. Listen to them, not me.

A Bose-Einstein condensate is a state of matter in which all the particles are in the same quantum state. This is generally only possible at very low temperatures, where almost all the particles are in their ground-energy state, thus the same state. The particles also have to be bosons, since fermions cannot be in the same quantum-state by the Pauli exclusion-principle. This is due to the wave-function being asymmetrical for fermions, symmetrical for bosons. Bosons are particles with integer spin, fermions are particles with half-integer spins. Since all the particles are in the same quantum-state it enables quantum-mechanical effects on a macroscopic scale.

I am mostly familiar with the physics surrounding Bose-Einstein condensates in dilute gasses and by that extension the Gross-Pitaevskii equation, which describes the ground-energy wave-function. My bachelor project involved making a two-channel modification to the standard Gross-Pitaevskii equation, thus avoiding the non-physical implications that comes when you control a bose-einstein condensate with a Feshbach resonance (near the resonant magnetic field the scattering length diverges towaards ±∞). It's however been almost a year, so it's not that fresh in my mind.

Well, frustration should be avoided. You're asking questions that people spend years of their lives learning.

So I'll touch on a few things for you...

Whether something is a particle or a wave is defined by how it interacts with objects, because photons interact with objects differently depending on the circumstances it is defined as being both a wave and a particle. Whether it behaves like a wave or a particle depends on the situation.

It's not a "false" vacuum unless it has not reached it's low-energy point. Vacuum energy is the minimum amount of energy that an area of space can be at, but it does not mean you can actually get any energy from this vacuum. To explain it in a sort of layman's analogy, picture a marble in a bowl. The higher the marble is in the bowl, the more energy. The "low-energy" point is when the marble is resting at the lowest point in the bowl. The shape of the bowl determines what the low-energy point is, but basically "energy" is defined as the difference between the position of the marble and the bottom of the bowl.

That's the extent of the information I'm comfortable handing out.

First paragraph there is more or less what I was going to say. Plus the following.

Part of the problem you might be having is because Bose-Einstein Condensates aren't a single class, it contains multiple different substances which all fit the 'single quantum state' that defines them, but with their own properties that distinguish them from other forms of Bose-Einstein Condensates.

The one I am most familiar with (though that's not saying much) are superfluids that exhibit properties like zero co-efficient of friction and infinite thermal conductivity.

Well, another part of the problem is that quantum mechanics really doesn't have a good explanation of gravity, or at least one fully compatible with general relativity. The concept of gravitons (subatomic particles that "transmit" gravity) is nice and all, but it just doesn't hold up with interactions between matter and spacetime.

A lot of quantum physicists write this off as "we'll never have a complete understanding", which kind of defies the point. They really are ignoring general relativity, as Abstractematics said. Of course, this is the kind of thing you won't find in most science books, so it's easy to get confused.

edited 16th May '12 9:27:53 PM by TotemicHero

Expergiscēre cras, medior quam hodie. (Awaken tomorrow, better than today.)

Let me introduce you to Godel's incompleteness theorems.

Kurt Gödel proved that there are some things in mathematics that are unknowable. Forever. There are some things about mathematics that are true, but unknowable using mathematics. Also, mathematics cannot prove its own consistency. This is true for any axiomatic system complex enough to use number theory.

Anime geemu wo shinasai!

True, and I do think gravity is mathematically more complex than physics realizes. However, the main problem is not mathematical as much as it is a lack of compatibility between the basic structure of the theories.

Basically, in a "transmission" case, like with gravitons, there has to be an emitter that produces them and a receiver that, well, receives them. The emitter in this case would be any particle or substance with mass. However, general relativity states that gravity is not a direct matter to matter effect. Instead, it's matter curving the spacetime continuum, which affects the motion of matter within said continuum.

So, in order for gravitons to work, the receiver has to be some kind of particle bound to spacetime itself. Since quantumm mechanics doesn't identify such a particle...it's clearly incomplete. And then when you get into the properties of such a particle (which would mimic the old and disproven concept of the "light ether", only with gravity) the whole thing breaks down, so...

Expergiscēre cras, medior quam hodie. (Awaken tomorrow, better than today.)

That's not the issue with gravitons as such. AFAIK, the problem is that, due to Relativity's corrections, gravity is not only self-interacting (a pain to calculate) but also warps what every other particle is doing.

edited 17th May '12 6:48:16 AM by Yej

Da Rules excuse all the inaccuracy in the world. Listen to them, not me.

Happens to the best of us.

Richard Feynman once told of how his father had trained him in pattern recognitions from when he was very young as the earliest form of mathematical thinking he could be taught. Then he worked up to mathematics and of course science. He was more or less reared completely as a scientific thinker. Perhaps inevitably Feynman became a scientist.

When he became a scientist, his father asked him about a question he had never been able to understand (I think it was something like "Where do extra photons come from in certain circumstances?"). Perhaps this was the very reason he had wanted Feynman to pursue science in the first place! So how did Feynman answer? Well he didn't see the problem. He tried to explain it to his father but he wasn't able to get his father to understand.

And if Feynman isn't able to absolutely put everything in layman's terms, even for a very educated layman, I don't know that we will be able to do that either. Certainly we have to accept the limits of what we can know.

Personally I'm holding out for TOE

Is he asking about the spontaneous creation/destruction of matter?

@Yej: There are actually a number of weaknesses with the quantum gravity theory and gravitons, although what you're describing is less a weakness of quantum gravity and more a weakness of the math used to map out gravity in general. But yeah, gravity is constantly in flux, warping everything from second to second.

In fact, it would not surprise me if it turned out that shifting gravity fields are the root cause for Heisenberg's uncertainty principle. Basically, you can't know a particle's momentum and position because local gravity fields distort them oh so slightly, and these gravity fields cannot be precisely measured without knowing the origin particles' momentum and position, and so on.

Either way, physics can be very complicated, so the fact that the OP is not understanding these concepts is a fair thing. If I recall, there was one mathematician who once said that it was too complicated to be left to the physicists.

Expergiscēre cras, medior quam hodie. (Awaken tomorrow, better than today.)

"but wave packets formed by superposition of waves."

The explanation of particles, combined with the also above concept that particles are best thought of as very high energy waveforms makes sense.

An roiling "ball" of high energy waveforms bounded by their own fundamental forces is hard to picture, but something i can indeed understand.

Perhaps part of my trouble understanding the matter form of Bose-Einstien Condensates is that know one has explained to me simply what it can do. I know, in general, how solids, fluids, gasses, and plasmas behave, but the Condensate appears to be a sort of super-stable fluid whose individual particles are more or less "fused" and i havnt seen anyone say "Yeah we made some and it behaved like lH" or perhaps "It was found to be a superconductor" or even "this substance would make a poor epoxy."

edited 17th May '12 5:58:52 PM by Stormthorn

While the breath's in his mouth, he must bear without fail, / In the Name of the Empress, the Overland Mail.

Part of the problem is that while the other four phases all describe sort of a scale of particle movement ranging from rigidity to free ions, the defining characteristic of a Bose-Einstein condensate is defined by quantum characteristics that don't cleanly reduce to a layman's version of "this is how well bits of it stick together". It's more like now the bits all have the same "settings" and this makes quantum stuff happen macro-scale because they don't cancel each other out anymore. Sort of. It doesn't help that you typically get one by messing with a gas, which is on the opposite end of what "cold" makes you think of.

And it's far from stable. Even a tiny amount of stray heat leaking into it can break that threshold and it just reverts to a normal gas.

edited 17th May '12 6:33:51 PM by Pykrete

Apparently there are many more "states" than the three or four states of matter commonly known.

So are quantum effects prevalent at low temperatures/energies?

Now using Trivialis handle.

The way oversimplified version is that most quantum effects cancel on the macro scale because they're constantly changing state, interfering with each other, what-have-you. Really low nigh-zero temperatures drop all the particles into the lowest quantum state because they don't have the energy to hit anything higher. So in those circumstances they're all uniform, and then properties that would normally be bouncing all over the place and cancelling out suddenly don't, and you get cool things manifesting on the macro scale.

edited 17th May '12 10:29:58 PM by Pykrete

here and here describes some of the properties of superfluid Helium and how its behavior differs from a normal fluid.

I find that people generally tend to underestimate, and by far, the importance and the complexity of classical mechanics, electromagnetism and statistical thermodynamics. I am far from an expert myself; but what little I get of them is enough to make me understand that they are subjects of great elegance and sophistication, and that a very solid understanding of them is pretty much vital if you want to be able to truly understand modern physics.

OP: Are you familiar with the Lagrangian and Hamiltonian formulations of classical mechanics? How is your understanding of Maxwell's Equations — and I don't mean just knowing of them or knowing what they roughly say, but are you able to use them in practice? What about fluid dynamics and the Navier-Stokes Equations? Do you grok Boltzmann Distributions?

I'm not saying this to discourage you — Heaven knows that I don't know many of these topics well myself — but if any of your answer to these questions is "no" and you have a genuine desire to really understand modern physics, you have to brush up on the basics. If you don't get statistical mechanics, for example, the Bose-Einstein Condensate will be entirely incomprehensible to you.

Gerard T'Hooft, a Nobel Prize winner in Physics, wrote a very nice page with suggestions for somebody who wants to learn something more about modern physics, with some nice links to online textbooks and so on; I hope that it can help.

edited 18th May '12 5:58:51 AM by Carciofus

But they seem to know where they are going, the ones who walk away from Omelas.