A...question.
Aug. 24th, 2012 11:15 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
avevale_intelligencerI'm wondering if it's possible to explain this to me without beginning with "It's not quite as simple as that..." Because I think it kind of is.
As I understand it, it's a basic principle of physics that all motion is relative, that there is nothing in the universe that is at absolute rest. The moon moves relative to the earth, the earth to the sun, the sun to the galaxy, the galaxy relative to the Local Group, and so on outward. I get all that; the first part I understand. It's the second part that gets me.
Because if A is in motion relative to B, then B must in respect of that particular motion be at rest relative to A. For every motion, every expenditure of kinetic energy, there must be a thing which is at rest relative to the moving thing. So surely, eventually, when you get to the end of that long string of movement and sum all the velocities and directions, logically there must be a thing, or a point in space, or a field or something, which is at rest relative to everything. If everything in the universe is moving outwards, there must be an in to be moving outwards from.
There is in the Sagittarian 'verse. Towards the end of the Sagittarian Age, scientists traced back the paths of all known metastellar bodies, based on data collected over the preceding several thousand years, and located a point in space which, according to their findings, approximated to the point of origin of the universe, and a team of specialists used one of the three remaining Gilchrist machines capable of large scale transmissions to travel there. They found, precisely at the indicated point, a roughly spheroidal black rock about eight miles in diameter, and for some years thereafter speculation raged across the nets about whether any of its surface features could be interpreted as deliberate markings, whether its age corresponded to that of the rest of the matter in the universe, and so on; in short, whether it had been put there or just got left behind. No conclusive answers were ever forthcoming; the only solid fact about the rock that could be ascertained was that, as far as could be told, relative to every galaxy, nebula, star, planet and asteroid in the universe, it was at rest. Everything was moving away from it, and had been for billions of years; it wasn't moving at all. And so, as ever, people made up their own minds according to their preferences. But that's fiction, and this is real life, probably.
I realise that this is a variation on the old Unmoved Mover argument which was one of Aquinas's proofs of deity, but that's not where I'm going with this. I would honestly like to know in what way my logic is faulty, if it is. If it can be done in a way that I can see makes sense, that would be good.
And if the Higgs field turns out to be the thing relative to whch everything else is moving, that would be rather neat.
As I understand it, it's a basic principle of physics that all motion is relative, that there is nothing in the universe that is at absolute rest. The moon moves relative to the earth, the earth to the sun, the sun to the galaxy, the galaxy relative to the Local Group, and so on outward. I get all that; the first part I understand. It's the second part that gets me.
Because if A is in motion relative to B, then B must in respect of that particular motion be at rest relative to A. For every motion, every expenditure of kinetic energy, there must be a thing which is at rest relative to the moving thing. So surely, eventually, when you get to the end of that long string of movement and sum all the velocities and directions, logically there must be a thing, or a point in space, or a field or something, which is at rest relative to everything. If everything in the universe is moving outwards, there must be an in to be moving outwards from.
There is in the Sagittarian 'verse. Towards the end of the Sagittarian Age, scientists traced back the paths of all known metastellar bodies, based on data collected over the preceding several thousand years, and located a point in space which, according to their findings, approximated to the point of origin of the universe, and a team of specialists used one of the three remaining Gilchrist machines capable of large scale transmissions to travel there. They found, precisely at the indicated point, a roughly spheroidal black rock about eight miles in diameter, and for some years thereafter speculation raged across the nets about whether any of its surface features could be interpreted as deliberate markings, whether its age corresponded to that of the rest of the matter in the universe, and so on; in short, whether it had been put there or just got left behind. No conclusive answers were ever forthcoming; the only solid fact about the rock that could be ascertained was that, as far as could be told, relative to every galaxy, nebula, star, planet and asteroid in the universe, it was at rest. Everything was moving away from it, and had been for billions of years; it wasn't moving at all. And so, as ever, people made up their own minds according to their preferences. But that's fiction, and this is real life, probably.
I realise that this is a variation on the old Unmoved Mover argument which was one of Aquinas's proofs of deity, but that's not where I'm going with this. I would honestly like to know in what way my logic is faulty, if it is. If it can be done in a way that I can see makes sense, that would be good.
And if the Higgs field turns out to be the thing relative to whch everything else is moving, that would be rather neat.
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no subject
Date: 2012-08-27 01:53 pm (UTC)"
The ignition of hyrdocarbons is only necessary because of the presence of something else: An atmosphere, which moves (on average) at the same speed in the same direction as the planet it sits on. If the M4 existed in a vacuum and the cars had frictionless bearings, then they would continue moving at the same speed in the same direction even with their engines switched off.
Again, it is only *acceleration* that requires expenditure of energy. The cars have to keep burning energy to "re-accelerate" every time a passing air molecule knocks a bit off their speed *relative to the atmosphere*.
Frome the frame of reference of the atmosphere, two cars are impertinently trying to shove bits of it in a direction it wasn't intending to go, and it resists that (inertia). It does change course, but only after it's given the cars a couple of relative energy demerits for bad bahviour.
From the frame of reference of the two cars, bits of atmosphere keeping hitting them in the windscreen at high speed, pushing them backwards... So they have to burn fuel to resist *that*, just to stay in the same place.