K^2

Interaction via Higgs is just as likely as it being a weak force. There are far more plausible explanations. But either one of these would go against predictions of SM, which would go into that very bad pile. Same as any other gauge field? There is really nothing special about Higgs. It's just yet another gauge field for yet another gauge symmetry corresponding to yet another charge. As soon as we've confirmed that yes, that's a thing that happens, Higgs became as well understood as electroweak bosons. It's not really so much another issue, as part of one big issue. You cannot break conservation of momentum without breaking conservation of energy, because they are consequences of the same symmetry. Another way to view it is through prism of relativity. Momentum conservation violation in one frame of reference is necessarily an energy conservation violation in another. So like you said, once the thing starts moving, it's extra energy it's producing, not just momentum. And that's a big part of why it shatters things like thermodynamics and electrodynamics, where you might not have thought it matters as much. But as soon as momentum conservation is out, everything else falls to pieces.

There are two different "if it works" scenarios here. If it provides thrust using some previously unseen interaction to transfer momentum, that'd merely be very bad. It'd mean we've missed something very big with the standard model. If it actually violates conservation laws? It invalidates over 200 years of progress in physics. Needless to say SM could be just thrown into the garbage in its entirety. We'd be able to salvage Newton's laws as an approximation of typical behavior. That's about it. All of the physics following it, Lagrangian Mechanics, Classical Field Theory, Classical Electrodynamics, Thermodynamics, Relativity, Quantum Mechanics, Quantum Field Theory, Statistical Mechanics, and basically every branch of science they have spawned, rely either directly on conservation laws being true, or on symmetries that are fundamental to these conservation laws. These are fundamental assumptions in absolutely every branch of physics. Violating them breaks everything beyond salvage.

That's true if your fuel is hydrogen. But with random atmospheric gas, you are likely to be producing secondary radiation. Think radioactive dust after a nuclear explosion. That dust didn't come from the bomb, but from irradiated environment. Many perfectly stable and safe isotopes have capability of capturing neutrons from a radioactive source and becoming radioactive themselves. So if you just scoop up atmo and run it through an NTR engine, you are going to be leaving a radioactive plume. Hard to tell if it would be significant, but the risk is definitely there. Now, Russians are currently working on a variation of NTR which does not use direct heating. They have a reactor that generates power, and an electric heater in the heat exchanger. So the propellant never gets close to the radiation source. That engine only exists on paper at the moment, but this is the sort of setup you can safely use in an atmosphere. You might have a bypass section in your turbine, similar to a typical turbofan, which would supplement TWR. You'd want to be able to disable bypass and go to a ramjet mode at some point, though. In fact, a thermal version of SR-71 Blackbird jets is probably your best bet.

Hyperbolic trig functions have the same period as regular ones. So it doesn't matter. True anomaly θ can have a domain of the form a < θ < a + 2À for any a. But some choices might be more convenient than others. I'd probably go with ±Ã€ for hyperbolic orbits just because it makes book-keeping easier.

Which is heavier, and the whole point here is to get a better TWR. If for some insane reason, you could not implement staging and had to use NTR for everything, increasing flow really works. Trouble is, you still won't have good TWR by the time you've plunged way bellow ISP of conventional rockets. So at that point, you're way better off to simply use a conventional stage to get the NTR to orbit. Once you're in orbit, TWR of an NTR is quite sufficient.

You absolutely would, because energy is quadratic on exhaust velocity, while thrust and ISP are merely linear. If I quadrupple the flow rate, with the same heat transfer, I expect halved exhaust velocity, meaning halved ISP, but double the thrust. (Half velocity * Quadrupple rate = Double thrust.)

Our Sun is 1.5M km across. Visible light is about 500nm. That means, with a 1m telescope mirror, Sun would resolve to a single point at a distance of just 0.3 light years. From 4 light years, a telescope with a 12m mirror would still see our Sun as just a single point. This basically means that even with largest conventional telescopes, best we can do are super-giants, and even then, all we get are a few pixels like that image above. There is one more options. Interferometer telescope arrays can, in theory, image nearby stars. Quality of images such systems produce is pretty bad, but you can get some useful information out of it. I believe, prior to New Horizons, best images of Pluto were due to interferometer array. In theory, one of these arrays should be able to image Alpha Centauri stars, but there migth be some limitations I'm not taking into account, such as glare or atmosphere. Even then, you'd get something even uglier than that Betelgeuse image.

Hcube, yes, parenthesis are missing. It should be -mu/(2a) Arkalius, still inversely proportional. Inverse proportion only talks about relationships between magnitudes. Double the one, and it halves the other. Fact that signs are opposite doesn't play into that part of it at all. As you've pointed out, it just means that proportionality constant is negative. Nothing wrong with inverse proportion being a negative one.

Not only do they exist, they are the principal way of generating electricity in RTGs. Unfortunately, they are very inefficient. So while they might be preferable in applications where weight and reliability are biggest concerns, if you are actually interested in generating a lot of power efficiently, you want to go with conventional heat engines.

Russian tech. It works, but sometimes needs a good kick. It's only when you don't have anyone on board to give it a kick when it's a problem.

That's the same thing. For simplicity, lets leave just two coordinates and talk about flat space-time only. Consider a space-time that's infinite in spacial dimension, but does not extend back past t = 0. In that case, universe is a sub-set of R², such that t > 0. This universe is infinite in x, and has a finite age at any point in this set. Only a finite sub-set of points is visible from any one point due to light cone. Consider a new coordinate system boosted at a Lorentz factor γ with respect to the original. Now the boundary is ct + βx > 0. Suddenly, universe has a wall. One that's moving at a speed c/β through space. If you have a definition of homogeneous or static to which this applies, please, let me know. Sure. But if I can pick an arbitrarily large subset, it guarantees that set itself is infinite. You cannot pick an arbitrarily large subset from a finite set. I don't see how you can talk about a finite time when I can chose a coordinate system with an arbitrary time span. On the contrary. I'm considering a more general case. I'm prepared to re-state all of the above with an arbitrary metric in arbitrary dimensions if you want. You cannot have a boundary one one coordinate (time) in one frame of reference, and not have boundaries on all other coordinates (spacial) in some other choices of frame of reference. A space without bounds requires time without bounds. Whether it's infinite or cyclical is dealer's choice.

Which is totally irrelevant. We don't care if there is a point out there from which light emitted now will not reach us. We care about light we're seeing now. And we can see all the way back to Big Bang. In other words, every single point in known space is visible with some sort of a time delay ranging between 0 and age of the universe. There are points whose CURRENT state we'll never see. But there is no point which we cannot see at all. And "our" sky somehow defines a coordinate system? You should look up definition of infinite. That still lets me place a boundary on the universe. A solid wall in space which you cannot cross. Infinite space in context implies infinite in any direction. If you have a starting point to time, then a trivial Lorentz boost makes that also be a starting point of space. That places a definitive age. If you're going to be picky about "infinite is infinite," then I'll just point out that having a boundary would break the homogeneity restriction. In either case, we're back to infinite, static, homogeneous being sufficient, because they imply everything else, including infinite or cyclic time.

I don't know why we bothered with relativity in the first place. We should have just used "ours" coordinate system and be done with that whole nonsense. Sorry. I'm being a bit rude, but the lack of preferred coordinate system is kind of the whole point. And any fixed duration will be different in a different coordinate system. And if you happen to have an infinite amount of space in any one coordinate system, I can give you a coordinate system in which duration of time is arbitrarily long. Moreover, if you have a coordinate system in which time is finite but space is not, any coordinate system moving with respect to it at any velocity will have finite space. Once you throw in field theory and uncertainty, the idea that you can have infinite space without infinite or cyclic time becomes silly.

In which coordinate system?

An infinite static universe cannot be young. It can either be eternal or have closed time. (Via relativity - no preferred frame.) Either case prevents light cone limits. All other considerations, including black holes, are trumped by thermodynamics. Infinite, static, homogeneous is sufficient condition for bright sky. Or uniformly lit, I should say. After all, you can have a universe with no stars at all.

Homogeneity is sufficient, actually.

And if you're not happy with this one, there are bits of the other one at the Smithsonian.

You are using anecdotal evidence to make general claim. I'm giving you numbers. I don't know what special conditions you were trying to do this in. I'm telling you conditions under which it should work, and under which I've seen water flash-boil in candles. One of the things which could make a difference between drops and splashing water in is the vapor shield. Your experiments would allow for minimal heat transfer from wax to water. Splashing water in would disturb surfaces of both water and wax ensuring maximum heat transfer.

That's a silly statement. Candle can, in theory, get up to the temperature of the flame, which is more than hot enough. Paraffin is actually a very good insulator. (k = 0.25 W/(m K) !!!) The convection in the molten pool is going to be almost zero, since it's heated from above. Really, the only limiting factor is the size of the candle. An experiment you might have done with 1/2" - 1" candle would be completely different from something in 3" -4" diameter. Add a glass or worse, ceramic container around it, and that thing will heat up even more. So, say you have 0.5cm deep pool of wax. Lets say, surface is at 100° and point of contact is at 50°C, which is somewhere in the range of melting points for a typical candle. That's just 2.5kW/m². Even looking at a pool 10cm in diameter, that's just 20W. For comparison, output of a tiny tea candle is closer to 30-40W. Larger candle will pump 50W into wax alone, quite easily, which should allow wax to heat up to 150°C or more.

You really shouldn't. That video is full of errors. First of all, there is no point in space from which light has not reached us, because while it's true that some parts of the universe are more than 14bly away from us, it's only due to expansion of the universe being faster than light. Light from eeach point still reaches us eventually, and since all known universe started in the same point, there isn't a part of it which we cannot see. Second, it is absolutely not true that infinite, unchanging universe would result in bright sky. In fact, if this was true, our local group alone would have been sufficiently large. We should se stars in all directions. We do not, because distribution of stars is not uniform. Stars are bound in galaxies, galaxies in groups, groups in clusters, clusters in filaments. It's this fractal structure that guarantees that number of stars a given distance away from us does not rise as rapidly as brightness of stars drops due to the same distance. Red shift is a factor. But if the stars were uniformly distributed at the same density they are found in Milky Way galaxy, it wouldn't have made a difference. There would be enough stars in our immediate neighborhood, to close to us for red shift to make an impact, to make the entire sky glow as a star's surface. I'm glad the video did not bring up another common misconception that interstellar dust is the cause of it. While it's true that we'd see a lot more light if there was no dust, if universe was, indeed, filled with stars uniformly, the interstelar dust would heat up due to starlight to the point where it itself glows same as the stars around it. So while interstelar dust makes the sky even darker, it's not the cause of it being dark to begin with.

And both of these are answered. No and no. There is no ambiguity here. And what do black holes have to do with anti-gravity? What the hell is "anti-gravity" is even supposed to mean? Outside of science fiction techno-babble it is a meaningless term.

Not really. You don't need all of the water to boil. A tiny amount is enough. Paraffin has pretty high heat capacity. It still needs to be well above 100°C, but for a larger candle, that's pretty typical. Besides, it's a trivial experiment. Just make sure you are in flame-safe area, have eye protection, and a wet towel handy. Basically, your typical working with flammables setup. If I can find a suitable candle, I can make a video.

Paraffin wax. While some candles are made from real bees wax, and there are variety of sealing wax candles, you pretty much have to be looking for these in specialty stores. Almost all modern candles, scented or otherwise, are paraffin. And yes, paraffin is most definitely the fuel for the candle. Wick just helps turn liquid paraffin into flammable vapor. What Psycix described is precisely what you've seen happen. Flash boiling, droplets of paraffin in the air, big fireball.

Standard model does not support tachyons that can be used for communication, either. Not quite as solid of a statement that you can't use entanglement, but it's still extremely unlikely. Seeing how black holes are, by definition, just various classes of vacuum solutions, a whole lot, actually.

There is a no-communication theorem on entanglement that basically says you can't do that. In fact, entanglement cannot be used for communication, period. It can only be used to augment an existing communication channel. (See: Quantum Teleportation.) Also, there is absolutely no reason that a black hole should lead anywhere. You can have an object that has all the external characteristics of a black hole, but is actually a wormhole. But you aren't going to accidentally make one of these by just making a black hole.