swansont

IOW, you are in a steady-state condition. The gradient causes flow, it is not preserved by it. I seriously doubt that. Which is what I expect will happen if you tried this. So the pressure will equilibrate much faster than any flow you are expecting.

And why won’t the pressure just equalize? Once it has propagated, the whole tube is at pressure. You’re all done. How big of a gradient are you expecting? How fast does the pressure differential propagate?

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Quite often the decays will strip electrons (shake-off electrons) as the charged particle is emitted/ejected. In alpha and beta decays. “The charge distributions of several alpha emitters were studied29-33 and they varied from -1 to +10 in the absence of internal conversion. Approximately 90% of the recoiling atoms carried zero or +1 charge and the mean charge was less than 1” https://www.osti.gov/servlets/purl/4262551 So at least 1 shake-off electron, and often 2 or 3. Sometimes more.

No, this does not follow. Why wouldn’t the pressure just go up? (also you seen to assume instantaneous freezing and melting, and that it would happen along the direction of the pipe, and not in the radial direction, from outside in. The thing is, some distance away, you are melting ice and having a corresponding collapse of 240 m of ice into 222 m of liquid water, which means there could just be a certain pressure increase, which remains static, and the system is in steady-state. No motion relative to the ground. I’m not seeing a net impulse exerted to the water.

Thanks Why do you think the water will flow, when it’s in a closed loop blocked at both ends?

How do you calculate this result?

! Moderator Note Staff gets to decide what is speculation, and one should pay attention to the explanations as to why that decision was made, and why threads are closed. Ignoring modnotes telling to not open a new thread on a topic, or to stop posting on that topic, is a poor tactic to implement One thing we’re not going to do is litigate these decisions in a science thread. Rule 2.5 says stay on-topic, and this is decidedly off topic.

! Moderator Note You need to establish that this premise is correct

Then space is being added between you and it. Independent of any motion of the object. Here’s a better explanation https://www.scienceforums.net/topic/123997-expansioninflation-and-the-separation-velocity/?tab=comments#comment-1164053

Are you used to following rules? I linked to them already

Its local speed is less than c

How much cycles will you get per night? Now, imagine running a heat engine at a higher temperature (i.e. at 373K instead of 273), and using the same heat sink. What happens to the efficiency?

Right. Which means the energy would be better put to use on a more efficient device.

Nothing has a speed that exceeds c. Expansion is not a speed as we normally discuss speed.

Until that becomes "all" then you can't really disagree. Some people will inevitably want more, and that's why the system fails.

Put a few kg of mass on top and see if that's still true. Well, it's a heat engine, so yeah. You convert some small fraction of the heat into work. In this case probably a very small fraction, since efficiency depends on the temperatures involved.

Hawking radiation won't leave at lightspeed, unless it's a photon. JC didn't say anything about a fusion reactor, he just said that you'd need to get the gas bery hot to get to that speed. No, it doesn't result in that.

They're part of human nature, so they are inevitable, and why nobody has gotten communism to work. It's never true communism. You end up at Orwell's "All animals are equal but some are more equal than others"

Then you can make inquiries and learn the technical limitations. Radioactive decay does not get you the power for this to be a viable energy source. It's got to be an actual perspective and not a fanciful illusion.

Yep. Higher income means different expectations and different worries, which are largely self-generated. You have the money and now you want a bigger house, a swimming pool, nicer (and possibly more) cars, kids in private schools. None of which is driven by need, but by expectations of self and society. Keeping up with the Joneses. And you can also end up with nothing saved up for retirement, because you spent so much on transient goods.

If you, and everyone else, are provided with your needs, then no actual money is required. The issue I think you are describing is driven by wealth inequality, which is (in principle) eliminated.

The mean free path is still the same, at the point you pop the container. Anyway, the relevant question is whether the thermal energy is comparable to the mass energy of one of the molecules, under the assumption that all of the thermal energy goes into one particle. If that's not the case, then there's not enough energy to get close to c. k is 8.6 x 10^-5 eV/K if T is 300K, then kT is ~ 0.026 eV You need ~ 1 GeV for each nucleon, to give you a KE equal to the mass energy (which would imply a gamma of a tad more than 2, which is v = 0.866c) So there will be a certain number of atoms where this will hold (around 10^11, so much, much less than a mole). You just then need the improbable circumstance where one particle has all the KE, and doesn't collide before escaping. But that's not really what the question was - it wasn't one particle going near lightspeed. John Cuthber's treatment is the way to go. And I'm still trying to figure out why escape velocity matters (or dark matter, for that matter. Space expansion doesn't give you a local velocity)

You're missing the point. If you have a containment vessel, the air pressure is irrelevant. It's how you can have vacuum chambers. The outside pressure, on the exterior walls is atmosphere, but the interior pressure is very small (essentially zero) because your chamber (steel, aluminum, titanium, whatever, but not probably paper) is rigid, and can withstand a pressure differential. So water in a tube can be exposed to the actual atmosphere on only one side. There will be pressure exerted by the vessel, and the value may be 1 atm of pressure, but it will not be the atmosphere that exerts it. No, the containment vessel will exert 1 atm on the water before you add the weight. In the water, everything is at 1 atm. (ignoring height effects for the moment). If the water exerts 1 atm, the containment vessel had better be exerting 1 atm back at it, if you are in steady state. If you take a vessel not designed to withstand the pressure, then sure, it is likely to fail. Way to cherry pick an example. It's like trying to demonstrate that flight is impossible by throwing a rock. OTOH, I have used vacuum systems, and they don't crumple. Been on a submarine, too, and survived being under several atmospheres of pressure differential. The notable part being these are devices designed specifically for the task, which a barrel (designed to hold liquid in) is not. Yes, we call it ice.

The best things in life are free But you can give them to the birds and bees Just give me money. That's what I want. Seriously, though, what's the alternative? Barter? Actual communism?