« on: 27/02/2024 13:31:16 »
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You take a mathematical (not physical) model of a hydrogen atomWhat is a physical model of a Hydrogen atom? Is it an actual Hydrogen atom? I'll admit an actual Hydrogen atom would show the behaviour of a Hydrogen atom better than a mathematical model of a Hydrogen atom.
In full pedant mode, I now wonder if the question is correct?What you mean is - since the final prediction seems to agree with the observations, that's all we're interested in. That's the engineer approach.
Once you have delocalised the electron into a real material, its behavior is going to be modified by the bulk properties of that material, so εvacuum must be replaced by εmaterial - electrostatics again.That's pretty much the argument that some existing texts would use. It's hand wavy as discussed in an earlier post.
but a mathematician or theoretical physicist might argue that whilst ε0 is a legitimate scaling factor, εr is always an experimental fudge factorNow you're getting somewhere and have elevated yourself up from the level of an engineer. Less empasis on fudge factors that just make things work and more emphasis on an underlying understanding.
Suddenly we have to introduce another concept me* (effective mass)I've already said something about this in the previous post replying to @paul cotter . There's more but this post is already long.
the permittivity of a material is a bulk property that is due to polarisation of charges within that material--does this have a real meaning at the atomic scale?I've already started to incorporate a discussion of using bulk permittivity into the (two) replies so far. It's a huge issue and one I would leave for another post. The main thing is, I have some ideas already. I just don't know if they're right and there's limited point in leading the discussion in some way as if I know.
Another conundrum for me is why electron and hole mobility varies when a hole is effectively an electron moving in the opposite direction, step by step.There's two ways sensible ways to go about answering that.
Take Alice and Bob passing each other in space, in inertial relative movement.
Alice can consider herself at rest, and Bob is passing at 100 kph.
Bob can consider himself at rest, and Alice is passing at 100 kph.
Alice has a clock that ticks at 1 second per second, but for her, Bob's clock is slow.
Bob has a clock that ticks at 1 second per second, but for him, Alice's clock is slow.
Thus, their clocks cannot be synchronised. This is basic relativity.
Well, yes, you can insert Carol who remains between Alice and Bob, for whom they are both doing 50 kph. For Carol, Alice and Bob's clocks tick at the same rate.
Your scenario seems to have the clocks meet at a common event, ...
... but to generalize a bit, and to remove all unnecessary observers, consider flat spacetime containing two inertial clocks at arbitrary locations, moving at arbitrary velocities, and set to arbitrary times.
In exactly one frame C will those clocks be moving in equal and opposite velocities. ...
Looks like the @OP has deserted the Thread.I'm alive. However, you are welcome to take over.
Why is it so Hard to formulate an Understanding of Quantum Gravity?The short answer is that I don't really know. It's easy to find articles written about how a theory has been (sucessfully) quantised BUT the attempts to do something that fail don't tend to make the journals or become good material for any magazine: "In this article we are going to spend hours going through an attempt to quantise a theory. It doesn't end up making sense or working at all.... but we're going to run a 6 hour session on it anyway."
If a basket full of apples can be weighed n mass found out.This is often half the problem. "Mass" isn't what we have come to think it is. In classical physics, things have a mass and it's a property that just should exist for any particle. Gravity is especially concerned with this mass because mass is the most important source of gravitation. Newton's laws of gravity have F = GMm/r2 and the mass is the ONLY source of gravity. General Relativity broadens the sources of gravity slightly, anything that is a source of what is called "stress-energy" and appears in the stress-energy tensor is a source of gravity. Mass is still the most important thing, this is the major source of gravity but other things like a flow of momentum through space can also be a source of gravity.
You don't need a wind.But where do they go? They are still subject to gravitation and no other force.
The sublimed water molecules are travelling at roughly the local speed of sound.
. I suppose the real question is why do comets and other icy bodies not undergo sublimation?They do, but it's slow.
There being no wind to disperse it, I guess it just sublimes a bit when the sun shines and recondenses in situ (in craters at the south pole) at night.Gases:
Let's see if anyone has objection to the explanation given in this video,Comment #1: It's about half an hour, few people will watch it.
Some life forms don't inhale CO2 to produce CH4. This alone is enough to reject your proposition.The proposition wasn't mine, it was credited to M. Russell at NASA.
a brief reading leads to a misplaced confidence that I have it "cracked".According to the news reports, a question very much like this was put out to school students in America for their SAT exam. You're in very good company if you mis-read or misunderstood it. Apparently almost everyone did exactly the same, including the people who set the exam because the mutiple choice answers didn't include "the right answer". Actually, it's still debated if "the right answer" is something you could really give without having a more detailed description of the situation so that you would know precisely where the observer is staying and if they had been allowed to rotate.