Black Holes, Singularities, Confusion

Yes, you could say space-time is a fabric. Black-holes ARE space-time, curved in a particular way. Think of a knot tied into the fabric. In fact, if you think of all particles as different kinds of little knots in the fabric, you are not too far from how we view things. This concept gets you away from the eroneous idea of space-time being an arena for "things" to live in. No, "energy" is a derived concept. You cannot describe space-time in physical terms. Only mathematics suffices at this level.

Heheheh... I tend to just read your posts and never reply because I know how ignorant I am going to look, namely because I am. Although I have an interest in pursuing physics (which we discussed before and thanks for the advice) I am still rather ignorant of it. I'm a guy used to studying the universe in much more collected forms. Okay, I am already clued into the idea of particles being "knots" of some sort, though it always seems intuitive to me to see them as involving space or energy and not time. I think its that time element which really throws me off and I start wondering if we are confusing mathematical models (a way we can describe/understand processes in an organized way) with underlying reality. Isn't time related to energy? Boy am I gonna look stupid but here it goes...We have e=mc^2 and tend to use c as a "limit". Isn't it possible that e is actually the limit, and so regulates what we can see as maximum v, which would be c? Instead of a space-time fabric, more of a space-energy fabric with perhaps a maximum level of energy allowed within a portion of space?Thus any area consists of a space-energy "density", and sufficient density creating what we consider particles or mass? That (to my mind) would result in "time" because really what we use to measure time could be thought of as limited by energy.Now here's a lame example. Say we use a quartz crystal for keeping time, current convention (as I understand it) is that as it approaches c it begins to slow down to an outside observer (and indeed does so in a measurable way).But wouldn't that make sense by assuming that it is the result of energy limits within the system? The quartz crystal marks time by oscillations which is itself movement, and so involves energy. Moving in a direction also involves energy (or at least an input of such). If there is only so much energy that can be part of a system then as it nears c, less energy can be devoted to movement in other directions (oscillations). The same would seem to be true for radioactive materials which would have energy devoted to movement rather than emitting particles. With a slow down in oscillation and particle emission the practical effect is a slow down in time, it would "age" less as energy is commited elsewhere.Now there could be a zillion things wrong with that crackpot theory, but the only one I am seeing is that energy is needed for acceleration and not necessarily to continue movement. But I'm not sure if that's true for particles near the speed of light, and I am not sure if that is true in a space-energy field where energy initially put into the system might count as stored energy and count toward the maximum.Anything you can do to return me to sanity, or at least disabuse me of my incredible ignorance, would be appreciated.

---

holmes {in temp decloak from lurker mode}
"What a fool believes he sees, no wise man has the power to reason away." (D.Bros)

No, that does not work at all.Let's leave the quartz crystal alone, sitting in some suitable protective module. But you get on a space ship, and speed up to near c. Relative to you, the quartz is seen as moving at near c. You still observe the same slowdown. But we have left the quartz crystal alone. Nothing has changed in that system which could account for the change.

Not surprised, but I'm uncertain about the example you gave.Isn't the observational difference from the vantage point of the person in the ship because of the speed of the "information" from the quartz crystal? That is it will take longer to reach and so appear to slow down?From what I understood most time dilation experiments focused on moving the object itself and seeing that time rate is changing there.In fact if time dilation happens in both directions why must it be accounted for in GPS measurements, wouldn't their mismatch sync?Obviously I'm not suggesting I have the facts here. I am only stating what misunderstanding I have.

---

holmes {in temp decloak from lurker mode}
"What a fool believes he sees, no wise man has the power to reason away." (D.Bros)

That would be the doppler effect time dilation.When you correct for the doppler effect, the relativistic time dilation remains. It is far easier to move the clock, than it is to move the observer. There isn't much doppler effect with GPS, because you are remaining at about the same distance from the GPS satellites. The time dilation is relativistic. There is an additional complication here. The GPS satellites are in a gravitational field, so one has to use GR, not just SR, to fully account for the effect. (Note, I'm far from an expert in GR).

Ahhhhh... you are now filling a rather large hole in my knowledge. I was merging them into one phenomena. I understood that. But if what you said was true, that for a spaceman moving to c the clock he observes outside his ship slows down, why wouldn't scientists just accelerate something and see if our clocks slow down? Would there be no way to measure that?

---

holmes {in temp decloak from lurker mode}
"What a fool believes he sees, no wise man has the power to reason away." (D.Bros)

As far as I know, most of the experimental data is with orbiting satelites. The situation is not symmetric, due to the different involvement of gravitation for the satellite and the ground based point. For a pure SR test, where there is symmetry, the two bodies rapidly move so far apart that measurement becomes difficult. The exception is in particle accelerators, where one can observe relativistic effects on the rapidly moving particles. But that's only possible for objects light enough to be accelerated to near c.I expect that cavediver knows more about what has actually been measured, and maybe it it will turn out that the kind of test you would like to see has been done.

It has been done several times, in a hundred different ways.
(In fact it has now been done so many ways experimental departments would find it difficult to secure funding to repeat it another way.)Just name whatever particular varient you'd like and I'll give you a link.

Ironically I lived next to Fermilab (walking distance) for a long time, and apparently my visits still didn't rub off on me. Then again I guess I was more interested in the subatomic particle research and conclusions than anything in theoretical (GR and SR) physics.I see what you mean though regarding a difference between satellites and particles in accelerators. I am hoping cavediver will have some info, and maybe some theoretical issues regarding energy v time.

---

holmes {in temp decloak from lurker mode}
"What a fool believes he sees, no wise man has the power to reason away." (D.Bros)

I'm not sure if this was regarding what nwr discussed or not. I am (as a spinoff of earlier discussion) interested in understanding how we measure time dilation, and in particularly the concept that one's own moving faster (close to c) results in a real dilation for the other.I was under the mistaken idea that only the "moving" subject experienced a real slow down, and any appearance of the "stationary" subject slowing down was just that, appearance.To make clear to anyone reading this thread, I am not at all trying to set out some new theory of physics or something. I understand that there is a concensus and evidence regarding GR and SR, as well as Space-Time models, I am only stating that I don't understand them and what seems more intuitive to me from my lack of knowledge.

---

holmes {in temp decloak from lurker mode}
"What a fool believes he sees, no wise man has the power to reason away." (D.Bros)

Your own motion has no "real" effect on anyone or anything in other reference frames. Let's say that you and a friend are in space far from any significant gravitational field (eliminating general relativity effects due to gravity). You are both wearing watches with second hands. Your watches are set to the exact same time, and they tick off the seconds synchronously. They completely agree about the length of a second. Each time one ticks off a second, the other ticks off a second at the exact same time.Now you leave your friend and accelerate up to near c, in fact to .866c. You make a flyby over your friend (so that you are neither approaching him nor receding from him, eliminating any doppler effects) and observe that his watch is ticking off the seconds half as fast as your watch.But your friend looks at your watch and observes that it is ticking off the seconds half as fast as his own.How can this be? You see your friends watch ticking at half speed, while he sees your watch ticking at half speed. Who is right?You both are. That's why it's called relativity. Observations you make relative to your own reference frame will not match those of observers in other reference frames that are moving relative to you. Your observations are correct for your reference frame, while the observations made by your friend are correct for his reference frame.The reason you each observe a different pace of elapsed time in the other's reference frame, the reason you each see the other's watch moving at half speed, is because there is no such thing as absolute motion. From your friend's point of view, from his reference frame, it is you who is traveling at .866c. From your point of view, from your reference frame, it is your friend who is traveling at .866c.Einstein developed special relativity (special relativity is the theory of relativity ignoring effects due to acceleration and gravity) by starting with the assumption that all physical laws everywhere throughout the universe would always operate unchangingly no matter the speed of the reference frame you were traveling in.This has some unusual implications, and one of them is the speed of light. A stationary observer measures the speed of light as c, which is actually 299,792,458 m/s. If the observer accelerates to .866c relative to his original position, he will still measure the speed of light as c, as 299,792,458 m/s. No matter how fast he goes, he will always measure c as 299,792,458 m/s.The rest of special relativity follows from this simple assumption.General relativity takes into account the effects of acceleration and gravity. There's a common question asked about the above example where you both observed time slowing down in the other's reference frame: when you return and are again stationary with respect to your friend, will your watches still read the same time, and or will they read different times? And if they are different, which one will be ahead of the other and why?The answer is that your watch will be behind, and that is because it was you who did all the accelerating and decelerating. Constant velocities are the realm of special relativity, while accelerating and decelerating and gravity are the realm of general relativity. For a more detailed explanation of what your friend observes your watch doing while you're accelerating and decelerating we'll have to wait for Cavediver or a suitable equivalent.--Percy

Hi Holmes, glad you're still with us despite your rather disturbing news. All the best to you and your partner in resolving the situation.First off, subatomic particle physics research and SR are utterly intertwined. SR is not theoretcial in the sense that every moment of every day a particle lab somewhere in the world will be confirming SR to the nth degree via its particle experiments. Ensuring that two particles circling a cyclotron in opposite directons at essentially c have a chance of colliding, requires making extremely accurate corrections to the guiding magnets based on relativistic calculations. Were SR not correct to our limits of detectability, these experiements just would not work. Furthermore, our entire study of particle physics is actually based upon the combination of quantum maechanics and SR - the study of quantum field theory (qft).Ok, back to some of your earlier points. What is hard to convey (even to other professional physicists outside the arena of fundemental phsyics) is how we have no underlying reality anymore other than mathematics. The only way of understanding the concepts is through mathematics - there has been a total disconnect with principles that we would call "physical". We don't model the physical systems with mathematics, because there are no physical systems to model. We look for consistent mathematical constructs that give rise to emergent physical properties. GR was the first full-scale example of this, although Maxwell's equations can be viewed this way in hindsight. This is not well portrayed by popular science, for the simple reason that popular science actively translates this work into physical, tangible analogies that are digestible by the layman. But there are no "particles", "things", "objects" anymore. The Universe, it appears, is a far better pure mathematician than any of us!Energy is very much related to time. "Energy" is a consequence of the time-translation-symmetry of the undelying space-time "fabric". "Momentum" is the same concept but related to the space-translation-symmetry. Given time is 1d and space is 3d, you can see how energy is a scaler and momentum is a 3-vector. Actually, there is a unified 4d quantity known as 4-momentum that combines the two. Oh, we have angular momentum becasue of the rotational symmetry of the 3d space. Thus energy is no more and no less fundemental than momentum and angular momentum.The wonder of SR is its simplicity. Everything within it can be broken down to considering rotations and translations in four dimensions, where instead of the 4d space being Euclidean, it has a twist that distinguishes one of the dimensions from the other three. For example, Pythagoras on this space is h^2 = x^2 + y^2 + z^2 - t^2 instead of h^2 = x^2 + y^2 + z^2 + t^2. That is all there is to it. In 3d, we have rotations and translations. In this twisted 4d, we have (x, y, and z) rotations and translation as normal, but we also have rotations between (x, y, or z) and t. We call these rotations velocity.If you have a competing theory, first off measure the complexity of your ideas aganist this. Oh, and make sure you can beat the record that SR holds for being the most successfully (accurately) tested physical thoery in history This is has been the wonder of 20th C funde physics - its unbelievable simplicty (once you've managed to shrug off the manacles of "common-sense" and "everyday-experience")

Nice explanation - just one caveat: SR deals with acceleration and deceleration without any problems. The Twin's Paradox can be a purely SR subject.

So in some very wierd way, Pytahgoras was right--the universe is made of numbersall joking aside, and I know holmes's questions are interesting, but could we perhaps steer this back to the blackholes? just a thought.

---

Want to help give back to the world community? Did you know that your computer can help? Join the newest TeamEvC Climate Modelling to help improve climate predictions for a better tomorrow.

Thanks to both Percy and Cavediver on the latest installments. The posts were helpful and hopefully further steps on a path to recovery. Intriguingly I never picked this up at the Fermi tours. I suppose if they mentioned it I just sort of yada yada'd it in my mind, simply to hear about the particles. Is it wrong for me to admit this is somewhat troubling on a gut level? It reflects something I mentioned earlier where I worry that we may be mistaking working equations with underlying reality?In any case, I will digest what you guys have given me and not continue diverting this thread away from black holes. I will likely create a new thread with more specific questions along these lines in a few weeks. In specific I am interested in energy as an emergent property (I guess that's how I'd read "consequence"?) of time-translation-symmetry. Is that (yet another dumb question) what is being captured in the schrodinger equation? Heheheh... I wouldn't call it a competing theory, just a theory competing for space in my head with a better one I don't have enough experience with. Unfortunately the better one does have its work cut out given the strength of my attachment to "common sense" and "everyday experience". Though I guess I managed to break them enough to handle QM in chem courses, this seems yet further counterintuitive.

---

holmes {in temp decloak from lurker mode}
"What a fool believes he sees, no wise man has the power to reason away." (D.Bros)