K^2

Big bang is a special case, and we don't know anything about it. All we know is that it produced the initial matter fields and began the inflation. Physics as we know it can only take over from there. Energy in vacuum does not produce particles. You need particle interaction for that. To put it simply, you need matter (and energy) to make more matter. Now you can ask, what happens if a particle does strike a warp bubble? And it will likely turn into a shower of particles which will make your radiation that much worse, But the energy holding the bubble is still just energy. You wouldn't enter a ship with a running bubble. You'd enter the ship, then the bubble forms and you travel. Then the bubble dissolves, and you are at the destination. The ship itself undergoes no motion. Space containing the ship moves, for the lack of better term. And like I said, there is no kinetic energy involved. (Other than kinetic energy of the bubble, which you do have to invest in.) You've missed the point. Read up on MWI and see if you can follow this experiment. Or, maybe, you can find a more detailed treatment of entanglement in MWI somewhere. I just can't type pages and pages of text on it. The short version is that the state of particles p1 and p2 does not change. So you know the state of the other particle, because it is in same superposition it started out with. What you can know in advance are measurement results made by O2, and that's only because O1 and O2 become ultimately entangled. We can discard it. Then QM is exactly the same as it is now. It only makes a difference on the level of matter fields. I don't ask you to take any of my words for granted. What you just said makes no sense. I suspect that you are mis-using a few terms. I recommend that you at least familiarize yourself with the basics of topology and get the feeling for what local properties and global properties of a topology might be. You understand basic Newtonian Gravity, right? Ok, I have a bouncy ball in my hand, and I'm going to drop it. How fast does it strike the floor? And I'm not giving you any more information about it. You know the theory, you should be able to tell me exact number without any other inputs. Ok, ok. I'll give you one. The bouncy ball is red. Now you have plenty of data to give me exact number. As for parameters of the theory we do know, I've already stated them in this thread. Four spacial degrees of freedom associated with pseudo-Riemannian manifold, additional degrees of freedom that transform according to QCD symmetries for some of the fields, and the most general Lagrangian that satisfies these constraints. For the rest of it, I'd have to ask you what you mean by time, because people use the word to describe several different things. Oh, and you are very confused on what holographic interpretation is all about. You might want to look up AdS QCD correspondence. AdS is about as simple as holographic interpretation get. Warp drive is a prediction. It's a prediction of General Relativity. And there is no theory with better support. Quantum Gravity is a direct consequence of Quantum Field Theory and General Relativity. Both verified to more than 12 orders of magnitude. It's an absolute certainty compared to a host of things you take as truths. Don't hold your breath. We might never have universal QCs that are anything more than toys. Specialized QCs already exist, but they are designed for very specific tasks. Feel free to point to peer-reviewed publications confirming your theory. Oh, wait. But I guess, you just have no idea what theory means. Or holographic interpretation, again. You really ought to stop using words you don't understand. It makes it very difficult to understand your questions. Information and knowledge are two completely different things. As much information as you've tried to absorb, you don't know anything about these subjects. And you won't know anything until you try to actually understand the underlying principles. And for that you need to start with a good course in classical physics, actually learn some quantum mechanics, get a mathematical background to keep going, and start actually learning what's going on with the science that's been established for a better part of a century. Then you can start to actually understand something. Nonsense. Details of their experiments are matter of public knowledge. It does not. You are arguing from ignorance again. There are no laws of physics requiring global causality to hold. Again, you are just making stuff up. All causality requirements are local and they are valid for any prediction of GR. Of course. Because that's when the first mathematically precise formulation, the Alcubierre Drive, was presented. But that changes my point how? You're still basing half of your assumptions on things that were mis-information already then. And lets get something completely straight. Warp Drive as a principle is absolutely solid. Alcubierre Drive is mathematically precise and physical. In that exact formulation, it is not feasible to construct, but it violates no principles. All of your arguments on that are complete and total ignorance from lack of understanding of GR or any physics beyond the very basics. Then we go into other Warp Drive models that try to make them more feasible. The best result to date is by Dr White. That involves approximations and might not work as predicted. It is, in any case, the best idea we have so far and certainly a step in the right direction. Again, the questions aren't about whether or not such geometry works, but whether or not it is stable. A distinction which, again, would be lost on someone who has no concept of how GR works. His experiments might or might not confirm the effect. None of that matters. If Dr. White's drive proves to be unstable, it simply means we have to look for other configurations to reduce energy requirements. There are no physical reasons for them to be that high, and there are no physical reasons for the device not to work at all. We might never find a configuration which we can build with resources we can reasonably get. That's always a possibility. But you seem to be under the impression that the underlying principles are less than solid, and that's just completely false. This has nothing to do with work by Dr. White or any one other physicist who worked on warp drives. We have the basic model. We know it is solid. We know it works. Feasibility of construction is the only unknown.

Not exactly. It's very hard to say what's actually bad. Some genetic conditions are obviously disabling, and there is no reason to take on people with these when you can take on healthier individuals. But it gets very shaky very fast as you go down to less obvious things. Maybe a particular genetic variation makes you more likely to get Alzheimer's, but it gives you a higher IQ. Do you want to just discard that? There are also plenty of things which you just don't know that they are a problem, until you end up with a small population and you get just the right set of genes present in one individual. So you have to take a look at why genetic diversity is important. And it's important for the same exact reason that inbreeding is bad. Every single person is going to have some genes "broken". Some of these might be responsible for producing melanin in your hair. Others could be producing some enzyme you need to survive. Fortunately, you have two sets of genes. Parental and maternal. And so even if you picked up a vital broken gene, the working gene in the other chromosome still produces what you need. In other words, you are a carrier for a genetic condition that's recessive on this particular allele. But you don't have a condition, because the working gene is dominant, and you're fine. However, you do have 50% chance of passing on that broken gene down to your child. If your partner happens to have the same recessive gene, and also passes it on, child will have two copies of the broken gene, and will therefore have the condition which could be disabling or fatal. Or it could be just blond hair. Fortunately, deadly or disabling conditions are rare, so the odds of two people who are carriers for the same condition are absolutely minimal. This isn't a case for siblings. Siblings share 50% of genome on average. Meaning that if one of them is a carrier for something, the other one has a 50% to be a carrier too. And like I said, everyone's a carrier for something. That results in very high chance of offsprings with various genetic problems. If it's something benign, it can stick in the population. If not, it's probably going to get filtered out fast. But you can also have something that's harmful, but not outright deadly or disabling, and that can lead to entire populations with serious health problems. With small populations, you end up with the same problem. That small population is going to bring with them their own sample of recessive genes. And after just a few generations, it's going to be almost impossible for two individuals to not have some sort of a shared ancestor. And that significantly increases odds of two individuals being carriers for the same condition. The rest is just statistics. Some recessive gene, just by chance, becomes extremely common in population. If it's something harmless, like blue eyes or red hair, it can stick with the ancestors of that small population. But if it's something disabling, it can result in all sorts of problems leading to a degradation and demise of the group. So what sort of a genetic diversity would you look for on a generation ship or an evacuation ship? You'd start by screening for known genetic diseases that are disabling or deadly. These people simply don't make it on the ship. I'm sure we can lose some very important people this way, but short term benefits shouldn't outweigh long term survival. Then you start looking at any conditions that are known to be, lets say, slightly detrimental. There would have to be a quota on these, and you should try avoiding getting multiple people with the same conditions. The last stage is going through recessive genes in general, and trying to make sure that the population of the ship is going to be as diverse in these, recessive, genes. If the gene is dominant, it's expressed, and you can check the health and abilities of the individual in other tests. Critical dominant genes will not be diverse, but they don't need to be. The rest will end up having sufficient diversity simply by random draw. Recessive genes are the ones that have to be checked out. Naturally, all of this is a bit oversimplified, but the method can be made rigorous with a goal of maximizing long term viability of the group.

It sucks that people don't have a clear distinction between heat and temperature, or how the two are connected, but I don't think we should be fixing it from weather reporting side. The purpose of a weather report is to let people adequately prepare for the elements. If a wind-chill of -40°C means that you'll be loosing heat as if it's -40°C in still air, well, you better dress yourself as if it's -40°C out there. So that really is the simplest way to report these numbers. I don't see any problem with it. They do report true ambient temperature as well, and in fact, that's usually the first number listed, so it's not like people aren't given a clue that there is a difference.

We do. It's a gauge field of Poincare symmetry, whose conserved charge is the stress energy. That doesn't mean we don't have any questions about it. It's just what a lay person, or even just a scientist from an unrelated field, thinks are the things we don't know is very far from the things we actually don't know. So your point stands, sal. But our current knowledge is far, far more detailed than you'd get the impression from popular media and most textbooks. P.S. ZetaX has demonstrated both a good general understanding of core physics and an ability to deal with advanced topics in a responsible manner. If anything ZetaX is more skeptical than I am. So it would be in poor taste to accuse him of doing anything but contributing to discussion.

That's completely false. Two principles are not even related. Ship doesn't move. It never moves. There is no "stopping", or "braking", or "changing" of any kind. You have zero understanding of the way warp drive works, and you continue being upset that I'm trying to explain it to you. That won't work. And the fact that quantum physics is actually my job doesn't give you a pause even for a moment? There isn't really anything to explain. It only looks like "spooky action at a distance" because you keep trying to interpret it as some sort of communication. It works the same way across the interpretations, but the most clear way is to look at it from perspective of Many-Worlds Interpretation. Observer 1 looks at particle 1 and becomes entangled with it. In other words, O1 goes into superposition of having measured + and -, with particle remaining in superposition of + and -, but O1+ state corresponds with p1+ state, and vice versa. Observer 2 measures particle 2, and likewise, becomes entangled. Now you have an overall superposition state |O1+, O2+, p1+, p2+> + |O1-, O2-, p1-, p2->. Observer 1+ and Observer 1- might as well live in different worlds. Hence the name of the interpretation. But if O1 and O2 meet and compare notes, O1+ will be talking to O2+, while O1- is talking to O2-. So no matter what each of them measured, at what time, and how, they will have agreed that states of particle 1 and particle 2 were measured to be identical. You can entangle non-identical particles. Right. Internet "scientists". Do you understand what topology actually means? If local properties are the same everywhere, that's all we need to know. We've known it since the 60s. We're just only now learning to make it useful. String theory makes no predictions that have been verified. Gravity is a consequence of a local Poincare symmetry. We understand it completely. Quantum Gravity is understood as a fundamental field theory, but can only be made practical use of as an effective field theory. I've pointed that out before. That's non-perturbative QFT, and it's what I'm actually working with. The problems are purely computational. These systems get infinitely complex, and have to be analyzed with non-perturbative methods. Both Lattice and various Feynman techniques are being used to make huge amount of progress. Structures of simple nuclei have been resolved in both of these ways, and the only reason we can't touch heavy nuclei yet is because of limited computer power. That's not a theory. That's you making stuff up. <More nonsense of the sort.> And the fact that you don't know any of the physics behind it doesn't bother you at all? He's making use of popularity of the subject. Nothing unusual about that. And he has not refused to give out information. His models are available. He is being a bit quiet about the experiment, but given information that has been released, that's also understandable. They are having serious problems with precision, and are worried about funding. What you are seeing is just media circus around the thing. From actual scientific perspective things are pretty clean. No claims have been made that aren't supported by models. And why should it? When a supersonic jet flies by you, at first, you hear absolutely nothing. Then suddenly sound appears, and you can hear it ahead and behind of you, and then the sound fades out in both directions. I don't know if universe would be ok with that. Except I do. I've heard this exact thing at numerous air shows. Universe doesn't care in what order the waves carrying information hit you. In fact, it doesn't care about anything that has to do with your perception of the universe, or what you think is or is not possible. If you want to understand something about the universe, you first need to get over the idea that your impression of it is somehow important or relevant to how it actually woks. You seem to be stuck in 90's media representation of what science is. That had nothing to do with state of science even in the 90's, and it has even less to do with it today.

Use of kg is just a simple way to put it into perspective. What you need is 700kg * c2 of energy. The exact form of that energy... Well, I can sit down and compute the relevant tensor for an Alcubierre Drive. I think, what you end up with is energy in a form of a field strength. Like energy of electric field. Except, it's negative. That's exactly the sort of thing you should be getting with Casimir Effect. Know what, I'll make a check when I get home. I'm on a laptop right now, and I don't have Mathematica installed here, and I'm not doing 4x4 tensor calculus by hand. When I'm back at the computer with Mathematica, I'll check what stress energy tnesor for Alcubierre Metric looks like, and compare it to the CE stress energy. I can also show you what typical tensors for a beam of light and stream particles look like for comparison.

Most likely. Though, I don't know where the humidity came from. Air from that polar mass was very dry.

Most of Norther U.S. is under dense cloud cover tonight, unfortunately, and I doubt it will be much better tomorrow night.

For docking, sure, but when you're buzzing by something at something on the order of 1km/s, and so you need to measure velocities from hundreds of km away, this gets really complicated really fast. So if you are hoping to do rendezvous or venturing beyond LEO, you are going to do something way more complicated. You're looking at multiple ways of gauging position, velocity, and acceleration, as well as some smart filters to combine this information to make the best possible guess on the running values. The coding for this wouldn't be terribly complicated, but it's actually more computationally expensive than you might think. On the other hand, if all you want is to be able to enter LEO, maintain roughly the correct orbit, and then re-enter somewhere over the ocean, you can do all of that with a GPS chip and an equivalent of the $1 micro controller.

Yeah, hard vacuum and 2.7K again. I hope that improves soon. Edit: Ah, a flare. Yeah, that's a legitimate concern.

Hyperbolic functions turns out to be a more common name. You start with definition of proper acceleration du/dt = a, where u = dx/dÄ is proper velocity. Because dÄ = dt/γ, we can write a = d(γdx/dt)/dt = γ³(d²x/dt²) when v is co-linear with a. (You have to take dγ/dt into account.) So the differential equation describing motion of a sub-light ship traveling under constant proper acceleration is x'' = a/γ³ for some constant a. For x'(0)=x(0)=0, x(t) = (c sqrt(c²+a²t²) - c²)/a. But x(t) is boring. We are more interested in x(Ä), and that's where things get complicated. Yeah, if you just want delta-V, and not how far you get in specific time with given fuel usage, it's much easier. That's a more elegant derivation than what I worked with, though. So thanks for that link. No. Matter, by definition, is stuff with rest mass. In order to have matter, you must have some sort of wave packets that propagate as massive particles. This is a far more complicated topic. I'm a particle physicist, and I still don't like to think about it if I don't have to. Fortunately, your opinion is not decisive in the matter. QFT says that region of space between two plates has a lower energy than vacuum. Now, you can say that it's vacuum that has a non-zero energy, and CE energy is still positive, just lower than that of vacuum, but from perspective of GR, the distinction is moot. For an Alcubierre Drive, all you need is region of space with energy lower than that of vacuum. That will provide you with negative curvature in the bubble, and that's the only thing you really need. So for the purposes of warping space-time, CE does give you negative energy. Like I said, there are still some questions there, but as far as Standard Model is concerned, it's all cut and dry. Can you practically create sufficient amount of negative energy this way? That's a different question. But not a problem of theory. It does. That's why it's called a strong condition. Standard terminology in math. And maybe the entire world is just your hallucination, and none of the equations work. That's still not a problem of theory. Again, from perspective of SM, we know how this works. If SM is wrong, that's a different matter. Keep in mind that Energy Conditions aren't fundamental principles. They would be nice to have, but we have not found any reason why they should be true. That's just because you don't understand something about the way warp drive works. It is not a PM by any measure. It does not produce energy and it cannot do work. It can move the ship from one location to another without using up any energy, other than what you waste in conversion, but that assumes that potential energy of the ship at origin and destination is the same. If it's not the case, you will have to expend energy to move "up hill". And like I said, there are fundamental theorems that say that energy is conserved here, so if you feel that it is not the case, you're missing something. If the above doesn't clarify it, and you still have questions about it, feel free to ask. Nope. Only local causality matters. There are laws to prevent anything from going faster than light locally. Quantum Mechanics is entirely ok with global causality violations. Yes. That's why I had to correct myself in an earlier post. I've said that global causality is only violated if there is suitable curvature, which isn't the case. Global causality is always violated by an FTL ship. You are absolutely correct about that. It's just not a problem. Not from universe. That's topologically impossible. Maybe from observable universe. And yeah, if you have a really large black hole, so that you aren't ripped to shreds by tidal forces, a warp ship would be able to dip a bit bellow the event horizon. Not very far, but that's still a very exciting possibility. Interesting thing to note, though, is that like for any object that would fall in, from perspective of observer on the ship, you'll never pass the event horizon. At some point, a Schwarzshild Bubble will form around the ship, somewhere outside of the warp bubble. This might prevent Cosmic Censor violations, but I'm not sure about it. No, not really. We know the underlying unified theory. It's a Yang-Mills theory on a U(1)xSU(2)xSU(3)xPoincare group. Unfortunately, it's non-renormalizable. But a renormalizable effective theory exists, which accounts for all quantum effects in curved space-time. It only breaks down near the plank scale. So long as the warp bubble walls are significantly thicker thank plank scale, we can model the whole thing. Bubble "dissolves" when you reach the destination. Detailed Study of Null and Time-like Geodesics in the Alcubierre Warp Spacetime. Light and radio waves propagate along null geodesics. Matter propagates along time-like geodesics. Complete understanding of warp drive mechanics is right around the corner. It's the work that we can finish within decades. What the engineering task of actually building something like this would be will only be clear then. If we don't find any unexpected loopholes, it's going to be an extremely difficult task. But it already seems comparable to any other way of achieving interstellar travel. There are no easy ways there. Unless we find a very serious and currently non-obvious loophole, we are not going to have an easy way to traverse interstellar space. And while there might be things marginally easier than warp drive, warp drive is the only one that's going to be worth it at that sort of expense. If a ship you send to another star is going to take hundreds of years to do a round trip, there is very little point. And building something like a generation ship is not a task that any one planet can undertake. We'll have to have the entire system working on this. All just to send a bunch of people on a one-way trip. How much more practical would be the ship that can make a round trip in just a few years? Even if it's just as hard to build, it's going to be worth it. Pretty much same exact things. We've just had people talk about sub-light interstellar travel for a few decades longer. Warp drive has to play catch-up here. But we're making solid progress. Keep asking questions.

Sorry, I got a couple of things backwards there on causality. I was thinking about time-travel. Alcubierre Drive certainly can violate global causality. Anything FTL automatically does. But it doesn't result in time-travel by itself. You need something else going on. I'm trying to figure out if there is anything to prevent you from using two Alcubierre Drive ships for time travel, but you certainly can't time travel with one such ship in asymptotically flat space-time. Local causality is never violated in GR, so I'm having hard time coming up with an example there. The main idea is that two "neighboring" events either have an objective order, or they are not casually related. That means you can construct history locally, and if you follow a particular worldline, there are no ambiguities or paradoxes. Two different worldlines, however, can have contradicting histories, in principle. Then you can get things like grandfather paradox, and so on. But these things can still be resolved through QM, because only local causality matters there.

The differential equations involved are quite nasty, as they have hyper-trigonometric solutions. If you want, I can pull up the relevant solutions. It requires negative energy density. It does not have to come in form of matter of any kind. Standard model predicts that Casimir Effect involves region of negative energy density. So we have a good lead on this. There are questions there, but it's very far from, "We have no idea." Violation of strong condition imply the rest. Strong condition is already violated in Casimir Effect. Warp drive cannot violate energy conservation laws. It's kosher under General Relativity, and GR has Stress Energy Tensor as a conserved charge under Noether's Theorem. Causality is not violated by a warp drive in asymptotically flat space-time. Causality may be violated in certain types of curved space-time by allowing a ship under warp to traverse an otherwise non-traversable space-time loop, effectively violating causality. But General Relativity already allows for that, and modern particle field theory does not require global causality to hold. Only local causality must hold, and local causality always holds in GR, with or without a warp drive. I suspect other "violations" you are alluding to also overlook the big picture in similar ways. Wall thickness is not reduced to Plank Length in this warp drive. That's kind of the whole point. By reducing the wall thickness, you can create a warp bubble with arbitrarily small amount of energy. So all of the energy requirements quoted above assume a "macroscopic" bubble. Id est, large enough so that conventional QFT can be applied. Quantum Field Theory in relevant space-time is well understood. It might require study to know what it will do to the incoming radiation, but there are no inherent problems with QM here. From Alcubierre's original proposal to Harrold White's version of the drive, the trajectory of the ship is pre-determined when the warp bubble is generated. In other words, if you are planning to traverse 1AU, you will exit the warp after traveling 1AU and no sooner. There is no emergency brake. That's unfortunate, but hardly deal-breaking in space travel. It is also entirely possible to communicate with the ship under warp. There is a blind spot ahead of the ship to which it cannot send signal, and behind the ship, from which signal cannot be received. But it can communicate with other ships and planets in transit as it passes by. There are even directions in which red/blue shifts are minimal, making radio communications completely trivial. I've actually read the article on null-geodesics of the Alcubierre Drive just recently. If you'd like, I can pull up some details. Harrold White's drive would have slightly different geodesics, but same general principles apply. And now we've gotten to engineering issues. I'm not denying that they are severe. But that's going to be the case with any method of interstellar travel. There are no easy ways. It's entirely possible that we'll never resolve these issues. It's possible that we'll never cross the interstellar void. But by this point, we aren't talking about something that's physically impossible. Just something we haven't figured out how to build. If you have more questions regarding particular theoretical issues, I can probably answer most of them, or at least point you in the right direction. Theory itself is very solid. Nuclear Physics was on shakier ground when they built the nuke.

That's two separate questions. First, Special Relativity makes travel to long distances easier. This has nothing to do with warp drive. Just simple physics. If there was no speed of light limit, or if it was really, really high, then it'd take you about 6.4 thousand years to make a round trip to Andromeda Galaxy at acceleration of 1G. You just can't accelerate to a speed at which this trip would be short without accelerating at a rate that human bodies cannot tolerate. With the speed of light limit what it is, the round trip is less than 60 years at the same 1G acceleration. This has to do with the way proper velocity relates to proper acceleration. The closer you are to speed of light, the faster you can increase proper velocity while maintaining the same 1G acceleration. So your crew will feel comfortable while the ship cuts through the space exponentially faster from perspective of the same crew. The drawback is that without speed of light limit, the round trip is the same 6.4 thousand years from Earth's perspective. With speed of light being what it is, the round trip will actually be over 5 million years from Earth's perspective. Now onto the warp drive. We are missing a few crucial pieces of the puzzle, and technology is very, very far away. But the theory is absolutely solid. Warp drive just works. I can get into some details about why it works, what the problems are, and what is still remains to be seen. But it all gets very technical very fast. I'm not going to insist that Human kind will ever build a warp drive, but everything we know says that it's at least theoretically possible. It'd be a shame not to try. As for the paper, keep in mind that this was meant to be a popularization. He does have more technical papers on the subject, as well as a series of experiments conducted at NASA to prove the concept. Reduction to mass of Jupiter was done before Harold White's work. He claims a mass of just 700kg is enough. Of course, that has to be 700kg of negative energy density, which is, well, problematic. But at least the energy scale is now achievable, and we have some good leads on how to come up with negative energy densities. Like I said earlier, actual functional technology is a long way off, but we are getting close to the point where it stops becoming a theoretical problem and becomes a purely engineering one. P.S. At a current rate, world-wide, we consume 700kg worth of energy in a little over a month. Just to put things into perspective.

You've never had one! The discussion is about Lagrange points, and all you've been contributing are some fantasies based on code that you don't understand anything about. The topic of n-body simulation in KSP has been discussed before, and a number of well-qualified people have weighted on why it would be very challenging to add it in a way that preserves quality of the gameplay. If you wish to derail a topic, at least do so on a subject in which you actually understand something, or take it to a place other than the Science Labs sub-forum. People have standards here.

Next thing you'd be telling me that you are surprised that some electrical engineers act elitist, because none of the electricians you're friends with are. You might not like to hear it, but you just keep exposing your ignorance of the subject. A coder is a mechanic. There is nothing wrong with being a mechanic, of course, but if that's all you are, there is nothing to be elitist about. These are dime a dozen. We are talking here about integrating equations of motion with a non-conservative potential, doing that about million times faster than real time, and with sufficient precision to extract meaningful orbital elements from it. This is not something you can ask a typical coder to do and expect anything but total garbage out. Granted, almost any person who knows how to solve such a problem is going to be able to put it into code, and so can technically be called a coder, but comparing these people with general population of coders is just laughable.

It's going to lens differently. There could be some asymmetry to lensing, and there can be blue/red shifts depending on direction of travel. I don't think it will look much different otherwise. General Relativity is still relative. You can look at it from perspective that black hole is static and the rest of the universe is flying by. So an object orbiting a black hole will orbit it exactly the same way regardless of whether it's moving or not. Of course, from perspective of an outside observer, orbital motion around a body traveling at .99c is going to look weird due to time dilation and length contraction. This is so regardless of the source. But with black hole, orbiting object itself can be traveling at high fraction of c, making it more pronounced. Actual collision is above my pay grade. GR is non-linear, so things will get crazy before the two event horizons overlap. Before that, a ton of energy would be released as the two accelerate towards each other. Once they merge, however, no energy can escape, so all that kinetic energy would end up contributing to new black hole's mass.

Station keeping in GEO requires very little thrust or total impulse, though. Orbital decay, on the other hand, is only significant at much lower altitudes, in hundreds of km above surface. There, it makes more sense to use conventional engines for occasional burns. This is quickly changing though, and might already be out of date. I was trying to find some info on Iridium NEXT, but I haven't found info one way or another on which propulsion they are going to use to maintain orbit. Current Iridium constellation uses occasional burns which you can actually see in the sky if you know when and where to look.

It's not. Which is why how you feel about these concepts is pretty irrelevant. The physics are exactly the same. The labels simply mean different directions. The fact that you, as a human, are stuck on this ball of rock, and have never experienced time as anything other than this rock's proper time is your own personal problem, and has nothing to do with the physics of it. I wonder what people were saying back when the Wright Brothers managed to get off the ground. "Didn't you guys ever hear of some American bicyclists who made a theory of using dead dinosaurs to get themselves not into the skies, but close to it?" The theory you are thinking of is called the Alcubierre Drive. Also known as the warp drive. It was actually developed by a Mexican physicist Miguel Alcubierre. The theory does involve negative energy densities, which can be interpreted as negative mass, but probably not the way you are thinking of it. And the NASA scientist you are thinking of is Harold White, who developed an improved version of the warp drive, significantly reducing amount of energy required, and further developed a proof of concept experiment that has been conducted at NASA. Warp drive does allow exceeding speed of light, but it also makes sub-light travel significantly easier. Stop, just stop. Please. This is total nonsense. Not only is the "theory" portion of this a total fantasy, but even the facts are completely wrong. Black holes do not reflect light. Gravity always affects light. And light only has an inertial mass, while lacking invariant mass, which is what people usually mean by the word "mass". It's good that you are interested in this, but you really need to do a lot more reading, and probably learn a lot of math, before trying to get into a discussion on the topic.

There have actually been satellites that do just that. GOCE is an excellent example. It's just that modern ion propulsion systems tend to be either big and heavy, or have very little thrust, as well as being rather pricey. Thus, limiting selection of missions where they can be used. But we'll probably see more and more of this as technology improves.

If it's a small centrifuge for testing things on rats, yeah, that could work. And that would be useful to try. I think, what they had in mind with CAM would have been quite a bit bigger, and there wouldn't be a good way to assemble it inside an existing module.

They actually are the same thing. Distinction is about the same as that between direction "North" and direction "Up". Yes, given a location on the planet, I can say that one is strictly vertical and the other is strictly horizontal, because we have a direction of gravity. But at another place on the planet, these directions are going to be different. We live in a four-dimensional manifold. Because the metric happens to be non-positive definite, making it a pseudo-Reimannian manifold, once you chose a coordinate system, you can separate directions into strictly time and strictly spacial directions. But in a different coordinate system, the direction of time will be different. So it will naturally pick up a spacial component from your original coordinate system.

I don't think that's ready yet.

I've written in Assembly and machine code across a range of platforms. I also know how to write code for integrating trajectories. I have written code that's perfectly capable of computing an Earth-Moon transfer. And yeah, I can do that in Assembly. Oh, and just so that you know, it's not 128 commands, because immediate operands are written into the code space, so you actually get considerably fewer than 128. This is a completely different class of problem. And like I said, if you have no experience with this sort of thing, don't pretend like you know what you are talking about.

What's the difference?