swansont

You need to clarify what constitutes an explosion. Is one fission inducing another enough? How many steps of a chain reaction are enough? Part of the limit on size would have to be from ensuring the reactions take place, rather than the neutrons just leaking out and rapidly going subcritical. You could make it smaller than was demonstrated, but it might not actually explode reliably.

There is no change in P, V or T ? This was never part of what I had been discussing. I wasn’t aware you were waiting for me to address it. With one ball it’s not a problem, though. So the number of particles is equal in each octant? What if there are an odd number of particles? You said 42 before I brought this argument up. I hope causality isn’t under attack here, too. 42 isn’t divisible by 8. Let’s make it 48 - 6 particles per octant. Why can’t that number change? Why can’t there be 7 in one octant, and 5 in another? What prevents that? It’s not momentum. They travel at different speeds, and there’s a finite transit time.

Yes. I didn’t introduce “single observer bias” “agenda” is offensive? You’re the one who stated a plan, not included in the OP. But there is no compression, and no heat flow. The entropy hasn’t fallen. AFAIK they’re wrong about that. Will you now, finally, address the outstanding questions: What is the mechanism that prevents more balls being on one side of the box*? At what value of N does the mechanism manifest itself? *This is a big issue, because if we have symmetry, I can draw this line along any axis. If it can’t happen, then doesn’t the number in each octant have to be constant? If it’s not, then some half has more than the other

It seems the answer is “no” Apparently it’s a slogan and not an obligation.

These are two separate issues. One does not follow from the other (emphasis added) The courts have ruled that this is not the case in the US https://mises.org/power-market/police-have-no-duty-protect-you-federal-court-affirms-yet-again They can back off and let you be attacked, and they are not being derelict in their duty. According to the law/courts. If someone is predisposed to using violence, giving them more tools to do violence won’t result in more violence? Interesting take.

I don’t have sufficient familiarity with the physics to have an opinion.

You had specifically focused on the CoM of the gas. You went out of your way to point this out. An observer traveling with the ball isn't really a viable approach, knowing full well we are going to move on to multiple balls, because we’ve already done this. Plus the view prior to this was an observer in the lab frame. You seem reticent to answer the question, which is quite obviously “no, the CoM of a single ball is not fixed” Indeed. One wonders what the point of introducing it was. Yes, of course, all if this posturing suggested an agenda. This “next stage” will be in a new topic, right? Can we get back to the discussion at hand? Belief is not a physics argument. It is obviously possible when N is small. What mechanism makes it impossible when N is large?

It’s a proposal, not accepted physics.

Explain the CoM problem for one ball in my example. Is the CoM fixed?

You haven’t provided the source (i.e. document/transcript)/ context of the quote.

When m goes to infinity, the mass of the gas is irrelevant. The CoM will be the same, no matter what happens to the gas. It’s a non-issue for this explanation

The collisions are elastic and the box mass is infinite. Ideal system, remember? If there is no displacement, there is no work. These collisions would increase, not decrease, the volume of the box, so no.

When the ball is traveling, the CoM is moving, so this isn’t necessarily a constraint but it’s an idealized system (we start with an ideal gas) so the container has a mass >> the mass of the gas. Effectively infinite mass. edit: xpost with Ghideon

V doesn’t change. No, that does not follow Start with one ball, with some energy E, under the conditions of an ideal gas, in some box with rigid walls. Obviously, it can be anywhere in the box. Same thing for two. Wile they will occasionally collide and exchange energy and momentum, there is no mechanism that requires one ball be on each side. Two balls being on one side does not require a change in volume. Three balls, four balls - still no mechanism. Any conclusion about their average position is statistical. It’s like a coin toss of multiple coins - it becomes less likely to get all heads, or all tails, but nothing prevents it. Now increase it to an arbitrary number N. At what point does a mechanism manifest that prevents all the balls being on one side? What is that mechanism?

The piston was your introduction - which violates the conditions of the problem - so this clarifies nothing.

You can point to unpredicted benefits from past scientific discovery.

A piston means V isn’t constant. position ≠ momentum Why does it break these laws? It’s not a low entropy condition, as such. Did they say that, or is that your interpretation? Saying that doesn’t make it true. How does this allow a jump to absolute zero?

! Moderator Note Details should be posted here. Posting to advertise a site is against the rules. ! Moderator Note Those are all questions that can be asked without prefacing it with mentioning youtube, or physics-free claims. Try again, if you can comply with the rules

What does equilibrium mean in terms of a gas? So the parameters are not well-defined in that situation - they can show large deviations. Also note I responded to your question about the 2nd law being statistical, not the OP. The “small number” as applied to the OP is fabricated You did, though. Your gas became regularly-spaced, with no relative motion. It’s true there’s no path to get to that state, but AFAIK, nobody is claiming that state exists They are not “representative” if the videos you are decrying do not use them. You are trying to use a response to one very specific question and apply it to a broader question, which does not necessarily share the same assumptions. Do you want to discuss the issue you brought up in the OP, fine - do that. You want to discuss issues arising in stat mech, fine - open a new thread and do that. Don’t mix them.

There is no such thing as touching when you get to the atomic level. Electrons repel each other, so at best atoms are close to each other, but quantum mechanics means the boundary of an atom isn’t well-defined. Surfaces are not infinitely flat, so there will be other atoms/molecules in there.

Who said they were non-equilibrium? You didn’t indicate N=42 before, and regularly-spaced is a new addition, as well as zero relative motion. Where did these come from? You can’t go changing the parameters like that. Wikipedia articles like this are more like a textbook, but there’s more in the link. Not sure why you are thinking the system is low entropy.

There’s no physics here. This doesn’t meet the expectations we have of speculations. We need a model, evidence. I don’t see any of that.

My own field is like that. Bill Phillips, who shared the 1997 Nobel for laser cooling trapping, loves to point out how that techniques is used in atomic clocks, and his funding from the Office of Naval Research has paid great dividends (in both technology, and training of scientists to engage in further innovation) A lot of relatively inexpensive table-top physics is out there.

You haven’t clarified anything. Does anything leave the device, in this water analogy? Usually water is thought of as being outside of the craft

It comes from statistical mechanics “Statistical mechanics postulates that, in equilibrium, each microstate that the system might be in is equally likely to occur, and when this assumption is made, it leads directly to the conclusion that the second law must hold in a statistical sense. That is, the second law will hold on average, with a statistical variation on the order of 1/√N where N is the number of particles in the system. For everyday (macroscopic) situations, the probability that the second law will be violated is practically zero. However, for systems with a small number of particles, thermodynamic parameters, including the entropy, may show significant statistical deviations from that predicted by the second law. Classical thermodynamic theory does not deal with these statistical variations.” https://en.wikipedia.org/wiki/Second_law_of_thermodynamics#Statistical_mechanics