joigus

+1. This is a very interesting re-focusing of the question. Maybe the OP is interested in it? I don't think it can be done with our solar system because AFAIK remains of supernova explosions are seen as halos of dust (e.g., Crab Nebula). I surmise that our Solar System is much older than the Crab Nebula...

I had a teacher of classical field theory many years ago who, answering to a student who complained for his constant use of tensor analysis, replied: "If you want to understand Chinese poetry, it's a good idea to learn some Chinese." I'm sorry for the use of overly technical gobbledygook as AxB = C. You want to understand cosmology, the nature of time and what not, that's fair enough. Why don't you meet me halfway (or a tenth of the way), and remind yourself of what multiplication and division of simple numbers is? You do need some mathematics if you want to understand anything at all about time and the big bang. You can't just declare simple maths as off-limits. Ordinary guy is OK with me. An "ordinary conversation about the origin of time" is a different matter. There is no such a thing. Let me give you an example: Would you ask an economist to explain to you about the economy, without using concepts as interest rate, inflation, GDP or the like?

I think it's surface chemistry we're talking about here, rather than wax changing phase. Otherwise it would be incompatible with the principles of thermodynamics, I think. Waxes and rubbers have some surprising properties. Rubbers, e.g., cool down when stretched. When long molecules cool down under situations that would normally induce a temperature increase, that's because the very long molecules get more ordered when stretched, instead of disordered. Not same case as OP but, as I said, "surprising" properties. I share the puzzlement. +1 It can't be just the temperature that does it. It must be a combination of temperature, moisture, and most importantly, polar bonding with molecules in the skin cells. Otherwise, I'm clueless about what goes on here. +1. I agree. Again, it must be polar bondings and their effect, having to do with introducing molecular ordering in the very long wax chains.

Interesting topic. Yes, please, provide more info.

Is there a positive invisibility?

Totally concur with @Janus & @Endy0816. I'd like to know who said that too, @Strange. (+1)3 Let me offer you a complementary picture of why everything running away from one point doesn't work. If everything in the universe were running away from one point, we would look at the night sky and see something very special at that point. That would be the point we're running away from. Instead, what we see is a series of spherical layers older and older in every direction the farther away from us we look. Until we hit the very feeble, very dilute image of a primeval plasma state of the universe (this is called the surface of last scattering). A picture of the universe when it was opaque to radiation, because all the particles were ionized (plasma) so it didn't let radiation through. That's a picture of a pretty early universe. And it appears more or less the same in every direction. So, where is the original point? I hope that helps.

Very good question IMO. +1. Not really. The key to this is what @Mordred suggested when he mentioned the key words "FLRW": Then he went into a very interesting argument that really this co-moving time extracted from FRWL model (exact solution of GR) is actually an average and it would be affected by corrections due to fluctuations in density (+1). That's my understanding of what he said, at least. So there would be local underestimations or overestimations of the Hubble parameter (see below.) <question for @Mordred> Would an underdensity lead to an overestimation of H (and thus an underestimation of the age of the universe), or the other way around? I'm feeling a little confused right now (I think it depends on the global balance of omegas for DE, DM,...). </question for @Mordred> If the cosmological principle were exact, the FRWL solution would be exactly how the universe evolves, and the age of the universe would be (proportional to) the inverse Hubble expansion parameter. \[\frac{a}{\dot{a}}=H^{-1}\] Where \[\dot{a}\] represents the time change rate of the expansion parameter a, which in turn represents "how far away from each other typical galaxies are", and is dimensionless. The Hubble parameter is the proportionality factor that tells us how fast a galaxy is moving away from us as a linear (directly proportional) function of its separation from us: \[\dot{a}=Ha\] Now, don't ask me why (ask @Mordred perhaps), but Einstein's GR allows you to re-scale time and expansion parameter at the same time for the whole timeline of cosmic events, if you want, but it doesn't allow you to mix both in this re-scaling. So all you would be allowed to do is a re-scaling of both for the universe as a whole. Something like this: \[dt'=\tau\left(t\right)dt\] \[da'=\alpha\left(a\right)da\] Where the primes indicate new variables and the d's indicate small increments. So all observers would agree on a universal time that would be possible to re-define by re-scalings. Mind you, this is not your familiar wristwatch time. It's to do with the expansion rate of the universe. As others have pointed out, there are many kinds of time you can define, depending on what standard or physical process you use to provide you with the clock, so to speak. When defining such standard clocks, you generally find observer-dependence. But as long as the FRWL metric is valid, it allows you to define a standard clock for all observers in the universe that are co-moving with the galaxies in the common expansion. You may re-scale such clocks, but all these galactic observers would essentially agree on it, because it's just the ratio of a and its time rate of change. And t=0 goes to t=0 under any re-scaling. The origin of time, within the model, is absolute. The timeline scale is not. The deep underlying reason is that there is a singularity at the origin. I hope that helps and I haven't made any gross mistakes.

I was about to talk about operationalism and how important it is and how many speculators forget that. Connection with what you would do in a laboratory is essential. You saved me some work. +1.

Brilliant explanation IMO. +1

Talk about Brexit.

I think "informed decision" are the key words for tackling this problem. The boxer should be able to decide given as much of the objective information as it's technologically possible. Also, we tend to think in terms of banning or just plain allowing; yes or no solutions for problems that admit graded solutions. If you think about it long enough, it's not difficult to see that there are ways to tackle this that take care of the risks without just banning the activity. Banning was good enough for pre-industrial societies. We can, and should, I think, do better than that. "Case studies" is another bundle of key words. The case of Anthony Joshua that @mistermack proposes, strongly suggests that not everybody would suffer the same effects, so proper monitoring of every sportsperson would be in order.

Gamma can never be zero.

Ok. Everybody gave such good and precise answers (+1,+1,+1) that I didn't know of anything else to say. Except give the complementary mathematical focus, which is my favourite. Mathematically, a reading scale normally involves something like (at least for most measures within a certain range for both T and X: T=T0+kX Your apparatus is sensitive to X, while your theory connects it to the readings T. One example could be temperature as a function of the position of the mercury column. The zero error would be the error in T0, whether T0 be actually zero or not.

I think something that may help most people reading this post is to provide simple examples of what you mean just after you've introduced some of your definitions. Great philosophers (especially philosophers of science, like, e.g., Bertrand Russell) always set up explanatory examples after an abstract notion was introduced. Examples are like the "laboratory" of philosophy. Help your potential readers know that you mean business. On the whole, I don't think for a second that getting an idea of what a TOE will look like will be helped along by philosophical thinking alone. I'm pessimistic if you want.

👍 I have no doubt you're getting better.

I'd choose good (and generalised) education above a good leader any time. Leaders I see as a necessary evil. Religion is never a good bedfellow of anybody. 😆 It's always worked for itself pretty well, though. Just one more thing. When you say "understandable message", do you mean politics or religion?

Maybe. But I don't think he would be interested in saving the world from a devastating destruction. He seems to be quite happy with us having a fair amount of devastating destructions every now and then. So the thing you suggest sounds to me something like: God: Let's send another devastating destruction and see if this person who doesn't believe in me can thwart me (God whispers the solution to the scientist's ear). Scientist: I don't know who's talking to me, but OK. It's possible. It's certainly compatible with the schizophrenic type that I can see depicted on the Bible. What terrifies me is the kind of psychotic God that our culture seems to have devised. What does it say about us as a species?

Yes, it helps. Thank you. Every bit of information that all of you are giving me helps. People on the spectrum, as well as people who've had experience with it. It's helped me anticipate many things and assess the emotional breakdowns when they've come. In the case of A, only once we've had an emotional breakdown. It was due to an obsessive series of thoughts in relation to something a classmate told him. Today we've had a similar episode, but it's been so much easier to control. Tomorrow he's doing his maths and physics exam. Everything seems to be going very satisfactorily. His family are doing a great work, I must say. I'm amazed that you discovered it so late... I'm sure there are many people out there in their 40's + that weren't properly diagnosed.

So right. So central. +1

I know what you mean. I think that's probably because today, rather than facing a problem of unavailability of information, we're lacking an efficient method to get to the relevant information we need. Our brains evolve far slower than the world of technology. And, as a consequence, connecting the dots is harder than it has ever been. I've learnt that Darwin had had Mendel's paper on his "to do" list, maybe for years. He never got round to it. Imagine how much worse it can be now. Maybe as we speak two people in opposite parts of the world have had ideas that are complementary and would result in a tremendous advance, and they'll never find out for decades just because they don't know how to sort out the information overflow. We may need a new age of search engines based on semantics, rather than the grammatical-lexical search engines we've got today. But that's easier said than done.

Intuition is very dangerous when dealing with QM. How can the Pauli exclusion principle be partially violated? It's a discrete symmetry. As Mordred referred to (+1), particle pairs in QM must be either symmetric or anti-symmetric by exchange of their identity. There's no way to be "a little anti-symmetric." STATE(1,2) = - STATE(2,1) (fermions) If, on the other hand, your assumption is that some particles become symmetric, while others don't, that's not consistent with the principle that particles are indistinguishable from any identical other. We can partially violate C (charge conjugation), P (parity or "inversion of space"), and T (time inversion), but not spin-statistic character. Unless you come up with pretty strong experimental evidence, and then; and that would be most interesting; with a serious alternative to relativistic quantum field theory, because spin-statistics connection is too deeply ingrained in it. The whole machine would go down.

Thanks for sharing. +1. I don't have time now, but I'll get back to you tomorrow, probably.

Suppose you produce yoyos. You make perfect yoyos, but the world no longer is interested, no matter what your passion and ability at making yoyos may be. Who's going to subsidize your yoyo-making? And what for?

The problem with this well-meaning idea is the law of supply and demand.

I also believe in a concept of money that is cyclic. But it's not just spend it; money must be extinguished. It must disappear at a rate that's equated with the rate at which it's issued. The first historical kind of money as unit of exchange is a very clear example of this. If you pump money indefinitely into an economic system, you've got a recipe for inflationary disaster. The modern concept of money is also cyclic. The problem with the present monetary system is not lack of re-cycling; it's that it's the banks who decide who's going to get it and who's not; as well as how much of it is put into circulation. An economic system that's workable, IMO, must define, so to speak, a socialist ground (minimum wealth guaranteed as long as you're healthy and not just a leech) plus a capitalist ceiling (maximum wealth allowed). 1) Everybody must be able to have their basic needs guaranteed 2) Nobody should be able to buy, e.g., all the islands in the Indian Ocean The reason for the first, in my view, is basic human dignity; the reason for the second, if nothing else, is the simple fact that there is a finite number of islands in the Indian Ocean. I know how unpopular this is in some quarters, but any other possibility is simply not sustainable, or ethically acceptable.