J Thomas wrote:Max™ wrote:On the subject of relativity precision, GPS affects us every day and ONLY exists because of relativity, and the accuracy of GPS is directly related to the level of precision in our understanding of relativity.
I'm sorry. This is utter and complete nonsense. I can't blame you for not thinking it through since so many other people repeat it uncritically. With so much repetition it must seem like it doesn't need any thought, it must be true or they wouldn't say it so much.
Our engineers don't need a complete theory to explain in detail how everything works before they can use it. If they built a GPS system without knowing about relativity, they could and would measure the systematic errors and adjust for them. They have to do that *anyway*, because they get lots of small errors from unknown sources, that add up. The systematic ones are the easiest to deal with. The idea that it's so very important that there is a theory which sort of predicts one of the systematic errors is ludicrous.
No, this is not nonsense, see, I understand relativity pretty well after the last twenty some years of study.
The effects gravity and velocity would have on GPS systems would lead to a discovery of relativity if it was not already known. It isn't "just an error" as you imply.
The fact that you think it "sort of predicts a systematic error" is ludicrous.
Current theories about what happens inside an iron nucleus tend to suppose that maybe something the size of an alpha particle tends to have some stability in there, and there's some sort of binding energy mediated by some sort of particle.... Some theories suppose an almost crystalline structure of smaller pieces. Others emphasize quarks. It might turn out that individual protons and neutrons maintain their identity inside a nucleus, or maybe they have no more existence than individual H2O molecules in liquid water. You can look at the electromagnetic radiation that comes out of nuclei to get some idea how they're organized, but when you induce them to radiate that stuff they are not in the same states they're in when they aren't radiating it.... It was only natural to assume that they have a structure analogous to electron shells, and interpret everything in those terms, and it's possible to get reasonable results that way.
There's only one sound theoretical model which explains particle physics, there are lots of theoretical structures and far more hypothetical explanations, but at least when I discuss a theory, I mean an experimentally tested and sound explanation for a certain set of phenomena.
So OK, I ask you again, when a nucleus emits a beta particle, did it create an electron from scratch just at that moment, or was the electron already there? Perhaps inside a neutron? And when a nucleus emits a positron, did it create that positron from scratch just at that moment, or was the positron already there? Perhaps inside a proton? Do you understand experiments which confirm one of those interpretations over the other?
The nucleus underwent a transition which released enough energy for spontaneous production of another particle.
I don't say the iron atom in the new state would have the same energy it had when it contained one more neutrino. How could it? That would violate various physical laws.
Iron atoms don't "contain" neutrinos, they are released in certain particle interactions, but stating they are contained within a particular atom is extremely inaccurate.
I probably don't understand all the subtleties of the conservation laws. I notice that when talented amateurs discuss this sort of thing typically some of them are confused. Maybe I could learn something here. If it's possible to set up special conditions that result in atoms preferentially emitting neutrinos (of a type which is currently unknown) in a single direction, how does that violate symmetry? It's an unknown type of neutrino, imagine that something as simple as an electric or magnetic field affected the direction that atoms emit these neutrinos. How does that violate symmetry?
A symmetry is best explained as the ability to rotate or reverse the orientation of an experiment without detecting a variation.
Sometimes a particle doesn't care if you point it up, left, rotate it 180 or 360 degrees, or move it two feet to the left or right.
Sometimes a particle doesn't care if it is yesterday or today.
Sometimes a particle doesn't care if it has right handed spin or left handed spin. If you look at an interaction in a mirror, you shouldn't be able to distinguish it from a non-reflected experiment.
When those symmetries are violated, that relates to a conservation law, as Emmy Noether noted.
But no matter, even if the neutrinos were emitted in all directions equally, all we need is a neutrino mirror and we can get well over half of them going in roughly the right direction. Currently I have no idea how to make a neutrino mirror, of course. And if it's possible I don't know how heavy it would be or how much energy would be required to maintain it. But hey, tell somebody in 1812 that you have a magnet you can turn on and off instantly, and they probably wouldn't believe it until they saw it. There were people making guesses that electricity was somehow connected to magnetism, but nobody had found a connection. Do you know that neutrino mirrors violate physical law?
I know that turning a neutrino mirror on right here would induce thrust uh... well, not sure which part of the planet you're on, or where the sun is relative to you, but right now where I am, the thrust would be almost straight up.
Sure, and if sugar wasn't stable against numerous effects and last a certain length of time you couldn't have a candy cane. But you can still suck on it, when it isn't being quite so stable.
Yeah, except sugar doesn't comprise most of the visible matter in the universe, and isn't an elementary particle, so this analogy is rather useless.
I don't propose endless free energy. If it turns out that we can convert an iron nucleus entirely into neutrinos, then after it is converted entirely into neutrinos it will be gone. That would be the end. Since neutrinos aren't observed to have charge, after emitting neutrinos an atom should still have all its charges. But it might not continue to be stable that way, and might eventually eject some charges. That could give radioactivity etc. Hoping that the whole thing could become neutrinos is pretty much a best-case wish.
Charge is a property of a particle, not something which would be emitted. Releasing neutrinos will have to reduce the mass of the constituent particles, and that will definitely change it from being iron.
Turning it entirely into neutrinos doesn't sound like an experiment I want to be around, go do that on a moon, one of the ones around Jupiter.
You aren't qualified to decide that. If the future path of physics runs qualitatively like its past and present, we will find that our current understanding of physics is fundamentally incomplete ad maybe flawed, but it still works adequately in a limited range of circumstances. What will be possible with the new physics, in circumstances we currently don't know how to set up? You don't know. If you did know, you would understand the new physics, and you do not.
You're proposing that while there are no wizards today, potentially there could be wizards later, and since I can't say what wizards can do, I can't reasonably say that it is unlikely there will be wizards in the future?
You don't know what is possible outside the circumstances you understand. You don't know what it takes to get outside the circumstances you understand.
Now, you're not qualified to say whether I know what the boundaries of my own understanding are.
I must have been unclear. Look, do you use electricity o make liquid hydrogen? Yes. Where does the electricity come from? A little bit is hydroelectric, and some is nuclear, and a whole lot comes from burning fossil fuels. Yes, you use fossil fuels to make liquid hydrogen. Similarly with hydrazine. To make the precursors you do various endothermic reactions, and the energy comes mostly from fossil fuels.
You need energy, not fossil fuels, that fossil fuels are cheap doesn't mean we can't make rocket fuel without them. There is nothing about fossil fuels which is required for production of energy, so your argument is broken.
You ever play one of those games where you drop coins into water and try to land them in the right spot? Crowbars are fine if you don't care what you hit. Just keep dropping them until you're sure you hit what you want. You can probably get a lot better precision with masers or maybe with particle beams. But that aside, it's in general easy to attack earth from space, particularly if you have spare mass to drop. And it's hard to attack space from earth. If you live on earth, you are better off not to create a culture in space that considers itself separate from your culture.
I'm pretty good at the coin drop games actually, but you can make a guided crowbar just as easily, though that isn't your point.
Well see, ecologists have harvested their low hanging fruit, and to make their next breakthroughs they need to build artificial sealed ecosystems and study them. We need about 100 glassed structures about one square kilometer each, a cost of perhaps $1 billion apiece. If all the money isn't available right away we could start out building a few of them and build the rest over time. We have to get this to test our ecological theories. It will be worth the money, I promise.
You disagree? You think the money should be spent on physics experiments instead? OK, is there a way we can resolve this scientifically to decide which experiments are worth more -- before we actually get the experimental results and find out what we win?
Why is there an either/or?
All science is a worthwhile expenditure compared to blowing shit up or bailing out bankers when they fuck up the economy.
You're making a very disingenuous argument here.