K^2

Yup, lets ask a bunch of armchair scientists on a game forum. Forget reading serious papers, that's for losers. Stop being ridiculous, it's not even funny anymore.

Erm... What do you mean? If you look at it from the other side, it's moving clockwise. And it has to spin one way or another, or it will collapse.

The video of droplets orbiting a needle requires a clarification. The droplets are neutral, so the attractive force is due to polarization, which is 1/R3 force. When orbiting a long cylinder, however, the net force in the transverse plane integrates to 1/R2, which allows droplets to orbit as if around a gravitational attractor in the transverse plane, while moving freely in the longitudinal direction. Picture changes near the ends of the cylinder, of course, but that's a more complicated discussion.

Hm. Has anybody built a proper sim with true physics and flight computer simulation?

There is no need to discuss stability. Each of these contains a quark and an anti-quark, because that's the only way for 4/5 quarks to have color-neutrality. This guarantees decay in far less than 10^(-10) of a second. The only impact these particles have on anything is small corrections on intranuclear forces, as do pretty much all quark bound states.

One of our sats was riding that rocket. Glad to see it making waves.

Still want it shiny. Mate surface is a bad sign on solder no matter the material. It's another matter if it doesn't happen as frequently with some solder types, and that shiny surface alone might not guarantee a good joint.

Is it ok that particle physicists have been talking about pentaquarks and tetraquarks for decades now? I mean, it's nice to have some experimental data, but they are making it sound like a revolutionary discovery.

Sure, but it's a useful one for understanding the topic. If you understand all interpretations, you shouldn't have any trouble sorting through entanglement and the non-communication. Non-locality is trickier, but this is still the correct route to understanding more about it. Even for a single sentence, this is a bad explanation for many-worlds. Suppose, I have a pair of spin-1/2 particles. First one has spin along z, second along x. I can interpret this state as many-worlds. For example, I can interpret it as worlds where measurement is taken along the z axis. In which case I have two worlds. First has states +1, +1, and second has states +1, -1. But I can also interpret this as worlds where measurement is taken along the x-axis. Now the two worlds are +1, +1 and -1, +1. And I haven't even taken any measurements yet. This is just an interpretation of superposition. Purely mathematical, mind. The correct one sentence description is, "MWI - superposition sets of wavefunction can be interpreted as worlds." Which isn't even a hypothesis, because it's a purely mathematical interpretation. The actual hypothetical part of MWI comes where it states that the square of the weights of the worlds containing observer is proportional to the probabilities of the observation made by observer. And this mirrors perfectly the CI's square norm probability on measurement. Again, they are mathematically identical, so not a single experiment could possibly distinguish between the two. I won't to be perfectly clear about this. Worlds in MWI are not the hypothetical part. Delayed choice quantum eraser proves beyond shadow of the doubt that this information is preserved, and interpretation of the superposition as worlds is purely for convenience. It's only the measurement part that is part of the hypothesis of the theory, and that part is shared with CI. And yes, I'm well aware that there are a whole bunch of really bad explanations/definitions out there. Especially if you open up Wikipedia. Take it from somebody who actually studied quantum physics for a decade. This is where you are making the critical mistake. You are confusing measurement and interpretation of a measurement. There are absolutely, one hundred percent deterministic definitions of the dynamics during measurement. One can write out an exact Hamiltonian for a double-slit experiment, for example. Although, it's an ugly monstrocity. And while I'm well aware that you don't know how it works, there are exact formulae that tell you what happens to the system during that measurement. There is no collapse. There is no collapse that happens as direct result of a measurement. The system simply goes from one precisely defined state to another precisely defined state. Collapse is interpretation of what happens when an observer gets involved. And the fact that you have to invent loss of information to explain it is very, very bad from perspective of every single law of physics. For example, given a collection of states with density matrix ρ, the rate of change of entropy under any conservative Hamiltonian is d<S>/dt = Tr[ρ,ln(ρ)] = 0. In other words, entropy of a quantum system cannot change under any interaction. Except, it somehow magically increases during measurements. CI throws in an arbitrary collapse. Information is literally erased according to theory, introducing absolutely irreversible processes. Except, they are irreversible under magical and unexplained conditions, precisely because CI never bothers to explain what actually happens to that information. Delayed choice quantum eraser demonstrates this arbitrary quality in when information is lost in CI. In contrast, MWI tells you exactly where that information is going, which allows it to preserve reversible time, among other advantages. The only further thing I can recommend you is stop reading Wikipedia and popular science literature. You are not going to learn anything about QM that way. Not without learning the basics. Open up any half-decent text-book on QM and learn how the measurements are actually performed. Look up EPR experiment, for example, and learn enough QM to be able to write out the Hamiltonian for it. It clearly demonstrates how the measurements actually transforms the system, and how collapse plays absolutely no part in it until you throw in an attempt to interpret the observations. CI and MWI are not features of the theory. They are tools for understanding how quantum systems correlate with observations we are making. When it comes to quantum teleportation, quantum encryption, and just about anything that has to do with entanglement, CI is not intuitive. MWI is. When you learn to start making correct predictions on quantum systems based on your favorite interpretation, you can start arguing about it. So far, you've demonstrated inability to understand something as simple as no-communication theorem. Which is like the entry level understanding of entanglement. Why do you keep arguing and insisting that your way is better when you have absolutely no results to back this up with?

There are no universes created in MWI. There is just one universe. Even "worlds" aren't really being created. They are simply orthogonal projections of the global wave function onto observer states. Again, you are not just drawing, but fervently arguing for conclusions on subjects you haven't bothered to even learn basics about. So what we really have is MWI, which gives a simple, fully deterministic explanation, or Copenhagen, which has a full paragraphs of, "we don't knows" just in the explanation. You are holding that razor by the wrong end, I'm afraid.

None of us mean any offense to you either. Just pointing out that this kind of reasoning is poisonous to society. If you want to check that experts are really experts and aren't just making stuff up, you need to spend a lot of time learning the theory and understanding what they are actually doing. If you aren't going to do that, any statement to the effect, "What do they know?" is bad for absolutely everyone. It's bad for scientific community, because we get less funding. And it's bad for the rest of society because they don't get the benefits of research that funding was going to get.

Occam's Razor is a guessing tool. I thought you didn't like guessing. Not to mention that there is only one universe in MWI and statement that collapse is easier is silly when you can't even explain at what time during measurement the collapse happens. Don't forget delayed choice quantum eraser. When we know in advance that all interpretations are equivalent, the easier interpretation isn't the one that is easier to explain to someone who's new to the theory. It's the one that helps you make better predictions with less work. This is why we teach variables and vectors in math when simple algebra is simpler. Complex tools lead to simple solutions, and MWI is one such tool. Once you understand it, you can make easy work of quantum encryption, quantum teleportation, quantum eraser, and a bunch of other experiments and practical systems which bewilder a lot of experts. Now that's a razor I can get behind.

Neither is there empirical data that supports collapse, because there isn't even empirical support for wave function, so as there to be something to collapse. Learn what an interpretation of a theory means. Also learn the difference between scientific theory, which requires support, and a theorem that applies to said theory. Later tells you that if you trust the theory, you trust results. If you don't trust MWI, you don't trust Quantum Mechanics at all. Every single confirmation of QM in general is the confirmation for MWI. Or Copenhagen. Or any other interpretation you want to dress the theory in. None of them are any more valid than any other. None of them can have more or less support than another. They are either all valid or all invalid. That's how interpretations work.

It's not a guess. It's mathematically equivalent. Do you understand a difference between a guess and a theorem? Or is mathematical theorem also a guess to you?

We have a single datum, Earth, which we can and are wildly extrapolating on. I agree that it shouldn't be used in the first place, and we should be extrapolating information from data gathered from everywhere else. But we don't have any, so a non-committal shrug is about as good as anyone should be able to give. That's not to say it's not useful to ask what would apparent silence of the stars mean if we find out one way or another. Because that's what tells us that knowing whether we really are rare in the universe is important. If it's easy for sentient life to evolve in a star system, then we are likely facing extinction from a not-yet realized threat. But if sentience just happens to be a rare gem, we can relax a little and work on building a grand civilization.

And that has absolutely nothing to do with MWI. There is nothing in MWI about parallel universes. MWI is mathematically solid and is equivalent to Copenhagen. Any complaints you have towards MWI go for Copenhagen as well. That's why they are called interpretations. They aren't separate theories. They are just different ways to assign intuition to the same physics. When you understand why collapse is equivalent to world-splitting mathematically, you'll have a much better understanding of QM. A propagating signal is basically anything that can carry information that's moving with respect to some point of reference. If it's moving FTL, then it's an FTL signal. Matter moving away at FTL speeds certainly counts. It's a separate issue that it took Big Bang to generate. Like I said, there might very well not be a practical way. But it is part of underlying physics.

Oh, yes, that's the educated thinking that will bring us forward to the stars! News for you, which you might have been unaware of. While Einstein's guess on applying principles of differential geometry to principles of general relativity where just that, a guess, albeit a very well educated one, since he proposed the theory, we've not only been able to verify it with precision of better than 11 decimal places, but we've been able to independently derive it from principles of gauge invariance. Same principles that yielded quantum field theory. The only other theory that has been tested with that sort of precision. It is, further, derived from the most fundamental symmetries we are aware of, making it both by far the best tested theory and the one with most concrete theoretical foundation. All other modern physics is derivative works. Modern CPUs are based on same "guess" being right. So is the laser in the mouse you are using. Most of the components of your cell phone. MRI at your local clinic. Should I continue, or are you getting the picture? Or are you still under the impression that this is just dogma being spread by some corrupt government-hired scientists? This is the kind of idiotic, ignorant, destructive talk that gets funding pulled from real research which gets us real results and gives us the technology we are using. I'm very happy with this sort of technology, and I want to see more of it. I don't want to see a bunch of Luddites who learned about science from a TV show they've watched once to keep throwing wrenches into that system. If you don't understand first thing about science, please, go p**s in somebody else's pool.

@PB666 It's not a paradox. It's disagreement of extrapolation from a single data point onto a full set and then finding a contradiction. When you extrapolate like that, not finding a contradiction would have been more amazing. All that the Fermi "Paradox" really says is, "We know bugger all about what's out there, other than nobody informed us of their presence in a way we understood." And that can be pretty much just shortened to "We know bugger all." So what I've said up there aligns with Fermi Paradox pretty well.

And some people like dub-step. I won't understand either, but taste is one of these things that defies explanation. Practical side of the matter, however, is that you are making a lot of rookie mistakes on QM and entanglement because you refuse to run the thought experiment through MWI.

Error most people make is assuming that Quantum means non-deterministic. It's the most determined theory we have, because QFT tells us that all of our past future and present simply exists in its constant state in the extend of the space-time, which covers the full set of points that constitute our existence. Even classical mechanics can't give you that, because there are always stupid questions like, "How do we know, something won't disturb it from 'outside'?" Or, "What was before the Big Bang?" These simply aren't issues in QFT. Most of the problems people who just read about QM have are with Copenhagen Interpretation. Frankly, so do most physicists who study quantum mechanics. It's an antiquated and mostly useless interpretation. It's still strictly deterministic in the big picture, but looks like hidden parameters and/or voodoo locally, which is bad. This is why I've recommended looking at QM from perspective of Many Worlds Interpretation in this thread already. There is no such bs in MWI. It is clear why it's 100% deterministic and most of the intuition you get about QM in MWI is correct. These are two huge wins right off the bat. Not that it doesn't cause some misunderstandings occasionally, but give it a break, it's still QM. As for time travel, it's allowed by gauge freedoms. You're free to believe that no practical way to time-travel exists, and I wouldn't be able to argue with it, but Universe is expanding faster than speed of light. So signals can clearly propagate over great distance FTL, and that already means that there are frames of reference in which parts of universe are traveling backwards in time. Yes, not anything you could use practically due to distances involved, but unless you want to join the likes of Flat-Earthers, you'll need to find a way to incorporate these facts into your understanding of reality. Local causality is a different matter, though. As far as we know, it cannot be violated. Which is good to know. Local causality violations would be rather bad for determinism.

When your statistics sample has a grand total of one datum, it's just stupid to argue about. We have one planet in this solar system that fully supports life we know, and it happens to be the one we live on. Given that probability of planet you're from being habitable is unity, this is useless information. Plus we have a few planets and moons that could have been habitable or might be partially habitable for life we know, plus another couple that might be habitable to life we hypothesize as potentially plausible. None of them have we confirmed or excluded possibility of life on. Even that would be a start. Knowing if Mars does or ever has harbored life would be something. But we don't know even that. So again, we're back to having a single data point, which is useless for drawing even the loosest of conclusions on based on Anthropic Principle. Regardless of how likely or unlikely complex life is, here we are. Whether universe is filled with civilizations, or there is just one, we're guaranteed to be on such a planet, which means we can't use Earth's history or our particular evolution or environment as any sort of affirmation or rebuttal. Which brings me back to my original thesis. What's the point of even arguing? If you're right, it's purely by chance. Might as well just pick a religion and stick to it at that point. What we do know is what we should be doing to rectify this situation. We need to comb what little of space we have access to and either find other life or confirm its sterile. That means more sophisticated missions to Mars, and a fleet of probes to Europe and Titan as the first order of business. If we find life on other rocks, it's data. If we know whether it shares origin with terrestrial life or evolved independently, it's data. If we find bugger all, it's data. With this knowledge, we can start making some loose guesses as to what's happening in the rest of the universe, which might tell us a lot about dangers facing our civilization, be they from within or without. Either way, we'll be far better off than anything we could achieve with these, frankly, theological discussions.

Actually, what stress-energy does is stretch space. The "bending" effect is just a consequence, and honestly, is just an interpretation. Take a clay disk, and stretch it locally in one area, then observe how it bends to accommodate the change. Fundamental math of space-time talks precisely about stretching and shearing of space-time around each point. The oddity of dark energy is not in what it does to space-time. That part we understand perfectly. The oddity is in the fact that this kind of deformation of space-time corresponds to pressure in stress-energy without corresponding amount of matter, including dark matter, to correspond to it.

So, let me see if I'm getting this right. Gravity is the strongest force. Which is why everything is flying apart at an accelerated rate? You'll have to break this down for these of us with just one Ph.D.

Which are several orders of magnitude lower for reactions we are considering. Organic chemistry on Titan would be completely different. You keep using examples of molecules we see in living things here, but that's just stupid. Yes, these will all be frozen solid. But there are plenty of compounds that are a gas at Earth temperatures, which will allow for interesting complexes that can perform all the same functions, because their bonds, and consequently energy barriers, are so much lower. Essentially, everywhere you see hydrogen bonds in Earth chemistry, you want to use van der Waals interactions in Titan chemistry. If you do the math on typical reaction rates with that taken into consideration, you'll see that you can have things happening at merely 100th or so of Earth rates. Also, as a general rule of thumb, if you are trying to make a thermodynamics argument when debating with a physicists, double-check your figures. This is the first thing we consider when we talk about viability of absolutely anything. If I was going to take your argument at face value and expand on it, I would be saying something along the lines of, "There can be no rivers on Titan. That would require precipitation, and we know that rate of evaporation drops exponentially with temperature, so you couldn't get enough moisture in the atmosphere for sufficient precipitation to occur." Except, methane evaporates just fine under these conditions, because methane has much weaker bonds holding molecules together. Enough so to mostly offset the temperature difference. Which is why landscape of Titan looks almost terrestrial. Same exact thing applies to chemistry, because it's about the same thermodynamics in the end. Temperatures are lower, but so is absolutely every barrier that needs to be broken.

Polar connections between molecules are only necessary because they have to stand up to the 300K environment. You simply don't need bonds that strong at 90K. What you need is a range of bonds that are very weak to very strong at a given temperature, and at 90K you have that range. Metabolic rates do, in fact, change exponentially with temperature. But our rates are limited by energy flow primarily. A human body has full capacity to self-combust, purely in terms of how fast it can consume hydrocarbons if it throws all its enzymes at it. That's several orders of magnitude on normal rates. We have regulatory mechanisms to slow it down, because waste heat is a problem. So we have that overhead unused here on Earth. I would still expect fastest metabolism on Titan to be no faster than hundredth or even thousandth of that on Earth, but who cares? Life there has nothing to compete with, all geological changes are equally glacial, and energy flow allows for just these sort of rates anyhow. There is no question that life that can exist on Titan can be engineered in principle. Environment is compatible with a form of life. What it comes down to, can life evolve over a few billion years on a moon where all processes are going to be a thousand times slower, and variety in available organic compounds is dramatically less.