swansont

I don’t follow this. There is contraction for any observer (or frame) moving relative to it. But it’s not true, so any conclusion drawn from it is invalid. Further, the thread is about superposition in relativity; relativity is taken as being true. If you have some alternative to SR, like a concept of intrinsic length, it needs to go in a thread in speculations

You’re taking “observe” literally. It’s a frame dependent quantity. KE is a relative property, just as length is. Why do you accept one but not the other? It was incorrect.

You would be wrong. How did you get this far in discussions of relativity without knowing this? Also, I will mention again that you continue to avoid answering my question about kinetic energy Your OP said nothing about this. No, the length depends on who observes it, as it always is with relativity. There is no intrinsic length.

If they aren't strong enough to challenge us and we are prone to be belligerent, how is it in their best interest to reveal themselves?

Did you mean 12 weeks? Weren't there tourists in space (briefly) back in October? I know Shatner played Captain Kirk, but he still counts as a tourist.

And how do you know "something stealthy" hasn't? Because you saw something that isn't (and has never been claimed to be) stealthy? To rebut the existence of stealth spacecraft, you have to be seeing the stealth craft. The ISS isn't one. It's like claiming that seeing a white horse proves that brown horses don't exist. I don't. That misses the point, which is it might end badly, and some people/beings might want to minimize risk. I also wear my seatbelt when I drive my car, even though I don't know that I will get into an automobile accident.

! Moderator Note Discussion on emergent phenomena has been split https://www.scienceforums.net/topic/126248-what-does-emergent-mean-in-a-physics-context-split-from-information-paradox/

Does it? Can you know ahead of time how somebody else will react? Are you willing to ignore the mountain of evidence of such scenarios ending badly? IOW, does your self-confidence that you will be welcomed as a liberator play much of a role? That didn't work out the last time I heard that phrase.

Sometimes is the key. If half the time you get a nice reception and the other half you get punched in the face, it's not very long before you have a bloody nose. Discretion is the better part of valor, as they say.

Humans sometimes respond to new things with violent opposition. It's not a unique behavior.

Where is "better" claimed? All I see is "more advanced" "The Day The Earth Stood Still" comes to mind.

How would we know? Anyway, https://en.wikipedia.org/wiki/Misty_(satellite) That doesn't actually support the argument.

Superposition refers to quantum states, or the addition of certain quantities. Length is neither of those. To any observer, a length has a single value. A quantum superposition is a quality of the particle or system in question and choice of basis states, and does not depend on the observer. The followup to this is: Is location an eigenstate? No. So there is no quantum superposition. As I believe you've been told before, length is not an intrinsic/inherent property; you keep treating this as some length having multiple values, and I think I've pointed out to you that we can look at the kinetic energy of a particle, which is another relative value. If you're at rest with respect to the particle, it has no KE. If there is relative motion, the KE is nonzero, and that value will depend on the relative speed, so it can have any positive value. But this doesn't seem to cause any conceptual issues (or maybe it does?), while length does.

The total output is 40 MW, but only about ~27 MW could be used; ~13 MW is carries away by neutrons And using any of that 27 MW would likely be counterproductive, since it would tend to cool the plasma down, requiring more input.

The US used to mandate draft registration (still does) and military service if your number came up. Seems to me putting yourself in harm’s way in service of your country would get more pushback than efforts to protect you, but this is where we are, I guess.

That would be dissipated from the system, yes. It’s the energy generated from fusion. From the link I found, you’d retain about 20% of that 16 MW. The neutron losses are presumably because tritium is used

I'm not following the math here How does 16 MW output produce 50 MW of waste heat? I don't think you are doing a proper accounting of the energy here. https://www.euro-fusion.org/faq/top-twenty-faq/how-much-power-is-needed-to-start-the-reactor-and-to-keep-it-working/ The power required to keep a reactor working is an interesting question. Energy input is required to keep the plasma hot, because most of the energy produced by fusion is carried away by the neutrons. However 20% is carried by the helium nuclei, which remain within the plasma, so it is possible to reach a point called ignition, at which the production of hot helium is enough to sustain the plasma and the external energy sources can be turned off. It is not clear yet however whether that will be the optimum operating regime in a power plant – being slightly below ignition may give better control of the reactor (while still producing plenty of hot neutrons). So the 16 MW output is mostly radiated away as neutrons - largely unrecoverable, and also a problem* There's no electricity produced anywhere in this process. They haven't gotten to the point of a self-sustaining reaction, where you can turn off the input thermal energy, because (from the numbers above) you'd need to generate ~120 MW for that to happen. And you need to generate more if you want to start siphoning some off to generate electricity. *fusion is sometimes touted as being clean, radiation-wise. The fuel itself will not be more radioactive, which is a leg up on fission, but these neutrons will activate the containment vessel. Yes. This is another issue not accounted for in the math. Q=1 would be a PR milestone, but not an indication that fusion power is around the corner.

I don't think this a matter of "forgetting" human rights. Governments have to be empowered to enforce isolation or even just mask mandates, and then have the fortitude to carry out the required actions, childish public reactions be damned. edit: this requires that they listen to the scientists, even when this means updating the response in light of new information.

That's why I specified sustained. But similarly, scientists have successfully done steps that would be involved in creating life. It's just a matter of time.

Same is true of sustained nuclear fusion, but that's happening all over the place The feasibility is debatable and that just kicks the can down the road about life starting.

How hard is it? We have one data point for life getting started on a planet with liquid water, and there is life. How does one extrapolate that to get a level of difficulty?

Not enough info. Does “Atoms from a person’s body” include air atoms that one has inhaled/exhaled? What counts as an atom being “in your body”? Does frequent contact include swapping bodily fluids (i.e. sex)?

! Moderator Note It's preferred that you have one topic per thread, so that followup discussion can be kept straight. (it would also avoid the jumbling of the links that has occurred, and which I have been unable to fix)

Photons weren't a part of physics back then anyway; Einstein had only submitted the photoelectric effect paper a few months prior to his SR paper, and the quantum nature of light didn't become mainstream physics until a bit later. Nothing in SR is dependent on light having a quantum nature.

This is a more succinct way of presenting it. You can argue whether it's the same photon but ultimately it becomes this set of questions, which are more philosophy (or zen koan) than physics. The physics part is that photons are bosons, so you can create as many as you want, and destroy them all, as long as you follow the other rules (i.e. conservation laws)