lemur

What's with the categorical appellations in this thread, mammals?

The Hohmann transfer was most helpful (I don't get the vis viva equation). It seems that acceleration within an orbit initially causes the orbit's shape to change from circular to elliptic, so for example if you would accelerate from the top of the mounting at geostationary altitude, you would eventually gain altitude as a result of your own inertia, because your orbital shape became more elliptical. Then, just by your own inertia, you would later descend to the altitude of the mountain again. I assume you would experience this as the mountain receding downward from you, since you wouldn't feel yourself shift into assent if you were moving only on your own inertia. I suppose the only way you could remain at the level of the mountain top would be to thrust toward the mountain in some way. I wonder if your sense of vertical/horizontal orientation relative to the ground would become confounded. The zero-weight (i.e. "weightlessness") is how I think of weight. I don't understand exactly what the 90% weight refers to. The problem I have is distinguishing between the force of gravity and the rate of acceleration toward the floor (when the floor isn't on the ground). Things get very strange when I think about being in an elliptical orbit where "falling" is increasing your altitude part of the time. Likewise, if you think about a very fast sustainable-altitude orbit that could occur if air-friction wasn't an issue (e.g. 10m above the surface of the moon). In such an orbit, gravity gets expressed completely as speed parallel to the ground. Yet, as you slow down below that orbital speed, gravity gets increasingly expressed as weight (i.e. rate of falling toward the ground). So depending on the speed of the ground, you could fall faster or slower and weigh more or less. I guess I have this figured out, but it still confuses me to think about gravity as a separate concept from rate of falling toward the ground. e.g. would you say we are actually as heavy as we would be if the Earth wasn't rotating, and that Earth's rotation lightens us a certain percentage - or would you say that our weight is accurate in the frame of the planet as it rotates and that it would change if the rotation-speed changed? I guess it's just a question of choosing a frame, isn't it?

I think you could wait until they start to become friends with someone they like and then bribe that person to avoid them. You wouldn't have to bribe EVERYONE, just people they got close to. Hired torture goes against the legality/ethical rule.

Imagine you are a planner for a government agency with the mission of torturing someone but you are not allowed to arrest them or use illegal means to do so, but you have a practically unlimited budget. Could you pay people to avoid contact with them thus isolating them as much as possible from social contact? Would this be legal and/or ethical?

So the iron cylinder was not a permanent magnet? Then the coil around did what exactly to magnetize it (e.g. was it just a conductor with a current going through it?)? Then as the current went through it, the iron cylinder rotated because the magnetic field generated by the coil was rotating? So I still don't get what shows that there was something else spinning counterdirectionally within the iron cylinder? What do you mean? I thought Einstein flew around in spaceships looking at clocks through telescopes and built nuclear power plants? I thought Einstein was to physics what Indiana Jones was to archaeology.

I heard recently that cows can develop digestive flora that can allow them to live on a mixture of low-nutrient grass and urine because the urine can somehow be broken down into forms of nitrogen that are available to the cow for protein-synthesis. I don't know how true this is or if humans could develop similar flora. Imagine being able to live by drinking ammonia and eating only carbs!

So there's some speed/route to travel between Hong Kong and London where you don't have to reset your watch? How long would that route take for the traveller and how long would their friends in London have to wait for them to arrive? That's sounds like a good question for an exam (which I would fail). Maybe you could make it harder by making them actually plan the route through spacetime and calculate the energy needed for a vehicle of a given mass. Good thing for me it's easier to come up with math problems than to solve them:)

Maybe, but it is the frame in which I experience gravity as weight and acceleration of falling objects. From this thread, it seems that I should have used "geostationary" instead of "geosynchronous" (not sure what "geosynchronous means now though); but my point was that if the ground continued up to that altitude (e.g. if a mountain went that high), you would become completely weightless at that point. Yet that doesn't mean that you have left Earth's gravity well. Likewise, if you were some distance from the top of the mountain, you could presumably take of with a hang-glider (assuming sufficient air density, which must by physically impossible with such low gravity) and accelerate to an non-decaying orbital speed. So the issue that really puzzles me is the relationship between gravity and falling/weight, because it doesn't seem to be a direct one. I.e. if you jumped off the mountain without the hang-glider you would fall, but if you use the hang-glider to accelerate, you would orbit weightlessly. If you would ascend to an altitude above the top of the mountain (above geostationary altitude), you would still orbit and not escape gravity, but you would have to fly away from the mountain in the opposite direction as Earth's rotation. But if you would fly the same speed away from the same mountain in the same direction as Earth's rotation, you would be leaving the gravity well. Granted this is frame-confounding in a sense, but in the context of standing on a mountain with atmosphere rotating at the same rate as the planet and therefore stationary relative to the mountain (i.e. no wind), it seems like your weight would change depending on your direction and speed. Then the bigger issue is what causes weight if not gravity only? Is it gravity combined with relative motion in some way that causes objects to fall? I.e. How does the ground and atmosphere slow down below orbital speed in the first place enough to cause things to fall downward into the gravity well?

So dilation only refers to the differential between two observers with regards to how each appears to the other. So once two clocks diverge, relative to one another they never become synchronized again naturally unless they reverse the differential that caused them to diverge in the first place?

First, imagine you have a perfectly rigid tower that extends from Earth to an altitude beyond geosynchronous orbital altitude. An elevator shaft in the center of the tower allows an elevator to travel up through the tower. As the elevator ascends, the force required to maintain constant speed decreases until it reaches geosynchronous altitude, where it remains stationary provided it is stopped and no further vertical force is added to it in either direction, right? Then, if it is moved to a higher altitude and stopped again, the force of the tower itself should work to push it upward (a sort of catapult effect), and this upward motion will be acceleration, right, since the angular speed of the tower is increasing as a function of its radius? Now, imagine you are observing from a satellite in geosynchronous orbit near the tower but not connected to it. Above you and below you are two other satellites that are orbiting at speeds appropriate to maintain constant altitude. The one below you would appear to be moving faster than you relative to the ground/tower, but the one above you would appear to not be moving slower but rather backwards relative to the ground/tower, right? Does this mean that altitude-maintenance is question of acceleration with descent below geosynchronous altitude but a question of deceleration with ascent above it? I'm not sure what is confusing me about this, except maybe I can't figure out at what point you would shift from using the ground as a reference frame to using yourself or some other point as a reference frame with the Earth simply rotating below. It seems like a point in geosynchronous orbit is a natural altitude above the ground, e.g. if a tall mountain or tower would extend that high, you would be able to go up it without "detaching" from the reference frame of Earth's rotation. But then by remaining in the same reference frame and ascending even higher, work would actually have to be done to prevent objects from ascending higher. I guess what this all boils down to is differentiating between net-force of ascent descent and the force of gravity itself, since any satellite experiences "weightlessness" but the phenomenon of weight itself appears to be relative to something else besides gravity directly. E.g. the elevator in the tower loses weight as it ascends toward geosynchronous orbit and gains "negative weight" as it ascends above that. So is weight a phenomenon dependent on both gravity AND speed, and if so speed relative to what?

The frequency of what? Electron oscillations in the atoms composing the objects? If so, wouldn't this change the relationship between the frequency of the particles and their motion relative to each other? I.e. the particles themselves would be "existing faster" but their faster existence would be relative to the same relations between energy and momentum that characterized them when their existence/frequency was slower, right? Or am I still misunderstanding something fundamental about this concept?

You're assuming that one would behave that aggressively toward the other if they recognized their spouse as an unknown stranger. Picture this: you find a note to yourself one day in bed while waking up as a single person and in the note, in your own handwriting, it says that you have a blind date with a person who is actually your spouse but that you've taken a drug that blocks your memories and familiarity with that person. So you show up at the prescribed meeting place and experience a strange sense of familiarity (deja vu) yet you don't feel like you know this person. Then you spend the rest of the evening getting to know each other with the comfort of test-driving a car that you don't have to worry about deciding whether to buy or not because it already belongs to you. (Sorry if the "car test-drive" analogy sounds like a cheap reference to sex - I'm not actually even alluding that sex has to happen or not; just that the people have a comfortable blind-date without pressure of acceptance/rejection - I think this would be good for a relationship). Interesting. I wonder if you would still experience symptoms of emotional/sexual withdrawal without consciously remembering what your forgotten life was like to cause you to feel something missing. I think relationship-withdrawal is a gradual process of becoming emotionally self-contained. If you couldn't remember your ex, you might not have anyone to blame the withdrawal symptoms on, but you'd probably still feel the pain of loneliness and rejection/failure. Without the negative feelings toward the ex, you might end up putting all that energy into seeking a new partner right away to end your discomfort and that could make you that much more vulnerable to a subsequent break-up, no?

I see your point about DNA showing that genetic/biological difference is negligible, but the problem is that people aren't generating these classifications for comparison out of thin air. They are the latest iteration of raciological classification, which tends to work because it has been a influencing factor in reproductive partner choice for some time. When the "2% genetic divergence" between humans and chimps is being discussed, do you notice that there is little attention paid to the fact that this difference must have been 1% at some point and 0% at some point before that when the two had a common ancestor? Then the question becomes what led primordial chimp-humans to begin selective breeding in a way that caused them to differentiate as breeding populations? Obviously, all species differentiation is evidence of what could be called "racism" in nature, but the question is whether this validates racism as a basis for mate-selection. I don't think it does any more than I think pure-breeding dogs is somehow contributing to the lives of individual dogs and the richness of their gene pool. So the question is what is the purpose of analyzing human genetic code for evidence of prior segregation would be except to re-institute such segregation in the form of supposedly "natural" population pluralism? Still, in a cynical way I guess I would be interested to know how rigorously partner-selection would have to be constrained and for what period of time to generate the amounts of genetic differentiation present in contemporary humans. Is this really a question of genetic differentiation, though, or are genetic archaeologists just finding specific "index" genes that can be used to statistically correlate among people who live in geographical proximity? In that case, the point would be so much to identify significant genetic differences as it would be to seek genetic evidence of relative regional reproductive autonomy and trace this to identify individuals globally in terms of relatedness to regional populations, right? So, if you wanted to, you could also perform statistical correlations by identifying global categories such as "people who can sing in key" or "people who like to dance" and identity genetic markers that correlate with the identified trait and then invite people to test themselves for genetic "linkages" to such categories? In that case, isn't it the a priori categories choses by the researcher rather than the genes themselves that decide which genes are compared statistically?

What is it about homosexuality that prevents people from making sperm-donations, adopting or otherwise contributing to child-rearing, etc.? You could just as easily theorize that homosexuality is nature's way of supercharging reproduction by encouraging more intensive divisions of sexual labor. I believe, for example, that many animals sex-segregate upon reaching puberty. I don't know when and why sexual activity occurs among the gender-segregated individuals, but it could have the function of stimulating them sexually so that they will go in search of heterosexual contact. In fact, homoeroticism could serve as simultaneous sexual play/practice AND repression of heterosexual desire, which could heighten the excitement experienced during eventual heterosexual pairing. You can't be too quick to make simplistic assumptions about sexual and other social behavior, because different behaviors can interweave in complex ways.

From reading that article, I can't see how anything about the physicality of the spin is proven as claimed. But maybe I'm misunderstanding the experiment. The magnet is suspended inside the coil and when electric current is used to create a rotating magnetic field in the coil, the magnet spins along with it? Then somehow another magnetic field is detected within the spinning ferromagnet that spins in the opposite direction as the magnet itself? And that shows that angular momentum is conserved? I think I'm understanding it wrong because I would just think the electric current generates a magnetic field and that pulls the ferromagnet along with it, the way compasses turn if you turn a magnet near them. But this experiment seems to be reporting some magnetic field other than an alignment between the electric-current and the suspended magnet?

So what does the spin do, then, besides create a "magnetic moment?" Does it change directions due to interaction with other particles? If so, does the direction-change involve inertial resistance?

Ironically, I don't think there's much forgiveness of "white men" in the culture that scapegoats them for the sake of relieving self-hatred and inferiority complexes among the post-oppressed. The guiding logic seems to be more, "whenever you feel angry, give your white-man punching bag a punch and you'll feel a little better." You must admit that this culture was developed historically by white men though, right?

Maybe sometimes sensory input signals get routed through memory lobes or something like that. It would be interesting to find out what brain process is responsible for creating a sense of recognition. If you could control that, it would really streamline arranged marriages, I think. Or maybe you could use it as a marital aid, i.e. if you could temporarily suspend familiarity with your partner for the sake of having an exciting 'first-date' experience.

I've seen that one before, but thanks. I think that was the reason I first wondered about combining sails with solar.

Isn't any form of momentum an expression of the energy put into accelerating the moving object to its given speed? Does that not apply to angular momentum of atomic electrons? So it either spins or it doesn't; and when it goes from spinning to not, does it lose energy and if so, how much? Where does/can the energy go? Likewise, when a magnet heats up enough for its spins to go out of alignment, does that involve a release of energy that was stored in the spin-alignment as frozen by the lattice?

Thanks for these terms. They make sense to me and they seem like they could refer to non-ions that still have net-charge. I am slowly learning this stuff, so I was thinking that "ion" referred to any sub-molecular particle with net-charge. So combustion is actually initiated by the heating of the oxygen to the point of becoming reactive? Also, what exactly is meant by "triplet" or "singlet?" Are you talking about the bond-strength? Also, by "abstracted," do you mean that somehow a H atom is liberated from the fuel molecule without being completely separated from it? Also, could you possibly directly confirm or deny my assumption that the amount of energy released in a reaction is due to the amount of momentum the particles gain in the process of re-arranging and accelerating due to electrostatic attraction? That's what is meant by valence/co-valence? Could that also be described as electrostatic-driven reconfiguration in that I'm guessing the electrons seek to pair up to somehow balance charge within the orbitals (this may be grasping at straws though - maybe it has to do with mass-oscillation harmonics? Is it known, actually?) Either way, it sounds like the atoms shift around in their configurations within the molecule rather than actually separating and rejoining in new patterns. This almost seems analogous to phase-stability vs. phase-change; or does this confound things even more to start looking at it in this way? No, I meant the molecule itself. I have always assumed that heat is always the result of linear motion of molecules colliding in a gas, flowing within a liquid, or vibrating in a solid. I never thought about energy being expressed as angular momentum of the molecules and now I'm wondering if that is the case. And, if so, would this mean that spin-energy would result in less volumetric expansion than linear motion of the molecules with the same amount of energy?

If your interest is transit, why not post/discuss some of the technical aspects you are interested in the engineering or other forums? Then, when your restriction period is finished, you can move on to discussing the politics of it too.

Was I not specific enough about the kind of energy I was referring to? I was referring to energy that would transfer from being angular momentum of the electron in question to being some other form of energy/work. There would be conservation of energy in that the spin would be reduced as an equal amount of energy transferred to another medium. Another way to put it might be to ask whether spin reflects an increase in the energy of the electrons' motion or just a change in the pattern of that motion?

We often feel either arrogant/egoistic/narcissistic or vulnerable by using the singular "I." Ironically maybe, I think it helps to overcome egoism/narcissism to practice making "I" statements simply as a factual description. E.g. "I used 'we' at the beginning of this post to refer to people who do what I was describing." Personally, I don't see what's wrong with using direct descriptive statements, though. Why not just refer directly to what you're talking about instead of preluding it with a reference to yourself and/or your co-authors?

It's been a while since I've (attempted to) read Einstein on relativity, but I distinctly recall an easy-to-read section near the beginning explaining time very carefully in terms of simultaneous reading of different clocks. I agree that if you describe time as "dilating," it implies a thingness to it but this may be more metaphorical than concrete. Describing space/time as a "fabric" also objectifies it, but in a way I wonder if Einstein wasn't onto some kind of deconstruction by using objectifying language for these phenomena while at the same time relativizing them in a way that cause you to question their absoluteness. It's interesting to think about the ontology of time and space, but I don't think you can get many physicists too interested in worrying about it as a serious issue. Most people seem more concerned with the instrumental application of the concepts to accurately model observable phenomena.