Isn’t the point just that with a uniform gravitational field, there’s no observable reference to tell your position? Just put the room inside a finite volume of uniform gravitational field, generated by a finite amount of mass.
Yeah, I’m still thinking about that case. I’m not certain whether the change in potential energy can be measured from within the room in that case, but I suspect that it can.
Although I had to look up the meaning of the word boulder, I may be able to help you (and a number of those out there somewhere) to get a more practical understanding of potential energy.
As a first approach, I would suggest the example of the ancient wall clock with its weight (basically a mass generating its respective share of force at the earth’s surface, called weight) resting at almost still-stand after having been pulled up to its highest level.
This ‘almost’ situation is interesting from a didactic point of view because it visualizes simultaneously the apparent dual state of immobility along with an energy producing movement.
Although the weight is practically standing still optically, you can hear the tick-tack of the clockwork induced by the weight’s unnoticed downward movement witness a constant supply of energy, i.e. the potential energy decreasing only at a very slow pace and therefore practically equal to the “working” energy on a short time observation basis.
In our case, it is acoustic energy materialized as a regular succession of spherical wave fronts expanding into the surrounding airspace, caused by the periodical increases of air pressure/density/temperature as a result of the transmission to the surrounding air molecules of the mechanical vibrations caused in turn by the impact of the anchor’s pallets on the anchor wheel’s teeth.
Replace the clock’s weight with a boulder, and you can reiterate your thought experiment on the basis of an easily understandable causality chain.
That’s all for the time being – an understandable explanation of what happens at molecular and particular level would fill ten times more screen surface.
There is no such thing as a gravitational bond between two masses – this is, alas, wishful thinking on which modern physics is based.
Attraction force is religious belief, and it remains indeed admittedly a complete mystery for the scientific community.
You know that a vacuum cleaner – wrongly called ‘Staubsauger’ (dust sucker) in German, and ‘aspirateur’ (aspirator) in French – does not attract air molecules into its nozzle, but only expel air molecules from the inside of the device through its impeller, leading to a decrease of air pressure on one side of the impeller, which causes air molecules to be “inrushed” from outside by the push of atmospheric pressure as long as any inside depression remains to be compensated.
There are only impact forces at work in a vacuum cleaner, and much the like in a gravity field.
We are not attracted by the Earth, but pushed onto its surface by a constant cosmic particle shower hitting the atomic skeleton of our bodies from the above space hemisphere, whereas the cosmic particle shower from the cosmic hemisphere below us is partially slowed down or diverted by impacting the atomic skeleton of 12,000 km of rock and iron. Hence the statistical difference of the total impact forces from above and below resulting in an excess push toward the antipodes.
How can anyone imagine attracting forces? Nano-spaghettis or what?
When you “suck” up a spaghetti, you know that it is pushed into your mouth by atmospheric pressure. But what you have to learn is that the cohesion of the spaghetti itself is resulting exclusively from cosmic particles impacting its atomic structure from all directions.
For a new start into an era of new physics, the most rewarding thinking that might be applied on this basis, may be trying to explain the Bielefeld-Brown electro-gravitational levitation effect…
:dubious:
Say, you wouldn’t happen to have the last name of Bogdanov would you? Otherwise I have absolutely no clue why every other word in that post is jargon that barely makes sense when stringed together.
Interesting theory. Can we have any evidence in support? Or did you just make it up? Because it is ingenious. Si non e vero e ben trovato.
It is an interesting hypothesis, in part because it’s testable. When I use a vacuum to suck something, there’s a limit on how much force I can put on it, since I can’t take the pressure inside the vacuum any lower than 0, and the atmosphere has a finite pressure. Similarly, here, there should be some maximum gravitational force possible, since eventually, if I have a large enough planet, it’s going to be blocking 100% of the gravity-pressure radiation coming from the opposite direction, and I can’t block more than 100%. So, what is this maximum gravitational force?
It seems all one would need to do to demonstrate your hypothesis and negate the force of this “pushing gravity” is to suspend a lead slab a few decimeters thick (sufficient to attenuate all but the most energetic cosmic radiation) or climb into a deep cave, leaving you with measurably reduced weight. Since this doesn’t happen, we can dismiss this ‘theory’ out of hand.
Stranger
BTW, Feynman’s Lecture’s on Physics has a good explanation of energy as nothing more than a bookkeeping trick. Unfortunately, I don’t have access to a copy right now, so I can’t tell you which book that part is in. But it might give some perspective on how energy really is a “fiction” in many ways, just a useful one.
I’m curious to hear more about your thought process here. What makes you think that the potential should be locally measurable? (Or am I misunderstanding what you’re thinking about?)
This seems to be just like the falling-elevator experiment. Just as there’s no local experiment (tidal-force measurements don’t count) to tell whether you’re in a freely-falling elevator at Earth-sea-level potential or in one floating in deep space (or in one 50 meters above Earth-sea-level potential), there shouldn’t be an experiment to tell whether you’re in an elevator resting at sea level or accelerating at 1g in deep space (or accelerating upward very slowly, at 50m MSL).
It seems to me that the place that the potential energy naturally should be is distributed in the gravitational field produced by the system. This is the way it works in electromagnetism (and Newtonian gravitation), and at least in some sense this seems to hold in GR (for example, with gravitational radiation, there is energy “in the waves”).
Whether or not the actual universe has fundamental attracting forces, I can’t see why there would be any difficulty imagining a system which does. It’s the easiest thing in the world to do; there’s nothing mathematically incoherent about it. It’s as easy as imagining a universe which follows the rules of Mario physics, or one where objects slow down of their own accord instead of maintaining inertia, or any such thing.
The only potential stopper is conflict with one’s preconceptions; to which, if the goal is to think about the actual universe and all the evidence indicates that the actual universe’s behavior really is a certain way, the proper rejoinder is “Stop having so many preconceptions.” It’s not for us to ask the universe to fit our preconceptions; it’s for us to make sure our conceptions match the way the universe is.
Energy (or rather, any measure of energy) is all bookkeeping, but it’s not a trick; it is a fundamental measure of the state of a system.
Stranger
Well, technically, if you suspend a sufficiently large mass above you, or go deep enough into a cave, you will weigh less. 
But I don’t know that there is some sort of universal ban on attractive forces.
What if the maximum gravitational force is many times larger than at the surface of the Sun (or many times larger than whatever the largest gravitational force we have knowledge of is). Further, what if the entire Earth only barely attenuates these gravipushers, similar to neutrinos in your [del]Standard Model[/del] Repressive Authoritarian Physics. Now Earth’s gravity is just a small effect, due to a small imbalance of gravipushers.
If the entire Earth only barely attenuates the gravipushers, but the residual difference in gravipush is enough to give me my weight, then there must be a heck of a lot of of them, because the gravipushers that hit me are going to have a far lower probability of interaction than the ones that hit the Earth. For that matter, they would also have to not be very attenuated by a neutron star, or neutron star gravity would be maxed out.
Begging the question.
The boulders are just a medium that must be harnessed to use the potential energy they have. Now lets just simplify this model you created. Let us turn those boulders into a mass that is easier to harness. In this case let us call the mass fluid instead of a solid. the water is stored in your room that is waterproof. on the hill it is a water tower. its easy to see the potential in this model because to harness this potential energy is as easy as hooking a pipe to it and run the fluid through a rotory actuator.
Just because your potential is crude and difficult to harness as a rock could be, dose not make for stored energy that could be applied to something advantageous or disastrous (like an avalanche).
Just my $0.02
Lets restate this more simply:
In the OP’s thought experiment, the two rooms are completely closed, and there’s no way to see out of them, ever. In that case, you simply have two closed systems, and the only way that potential energy makes sense is in reference to what’s in those closed systems. So the boulders do in fact have the same potential energy, relative to everything else that can be measured in the room with them.
The term ‘potential energy’ is always considered in relationship to other things.
This is no different than kinetic energy. Lets take those two rooms again, and state that they are both closed and no one can see outside. But one is going 1000 mph, and the other isn’t. Now fire an identical gun in each. Which bullet has more kinetic energy? The answer is that the amount is the same in each, if all we can ever measure against is other things in the room. For that matter, it’s kind of nonsensical to say “One is going 1000 mph”, without sayign what it’s going 1000 mph in reference to. Kinetic energy, like potential energy, is not an absolute. It’s measured in reference to other things that you can measure.
Here’s another interesting thought experiment. Lets put a boulder at a point in space where it’s exactly balanced between the gravities of the Earth and the Moon. It’s just sitting there. I can give it a nudge with my little pinky and send it ever-so-slightly towards the earth, and that little tiny shove will result in devastation as it accerates through the gravity well and impacts the earth. Or, I can give it a tiny shove and send it towards the moon, with the same effect.
So what is this boulder’s total potential energy? Is it the potential energy it has relative to the earth, plus the potential energy it has relative to the moon? The answer is that you can’t look at it that way. You can only measure its potential energy relative to the Earth or Moon. Potential energy is only a meaningful concept when relating objects to each other, and not an intrinsic property of the thing itself.
Thanks for the compliment! Would you ask evidence from Mr. Higgs in support of his bosom? As to the meaning of ‘ingeniuos’, I looked up my French dictionary under ‘ingenieur’ (engineer): it stems from ‘engin’ (war machine). I suppose this refers to the genius of Leonardo Da Vinci, who’s bread-winner was indeed the design of war machines – mine was translations and now I’m retired (which doesn’t mean I’m ‘tired again’, i.e. re-tired, after getting tired from doing translations… ).
No, I didn’t make it up – I’m just playing Mr. Higgs…
Back to serious: I guess that “Si non e vero e ben trovato” means approx. 'if it’s not true, it’s still a good find". Again: is Higg’s bosom a good find? If it’s true, yes. Anyway it is considered a good enough find to justify the 10 billion dollar LHC, isn’t it? So my theory of us being pushed instead of attracted towards the Earth’s center might well deserve a 10 billion dollar website for being discussed in detail by non-conformist scientists…
Thanks again for the compliment (it’s so rare on this kind of forums)! However, I’m not so sure my gravitational hypothesis is testable: the effects to be expected from the experiments I have imagined so far would all be equally found with a hypothetical attractive force as far as could be measurably assessed. For the time being, I stick to the axiom that any kind of bond between two distinct masses, or causing the coherence of mass itself, could only be magic.
About fifteen years ago, I already explained this to friends and predicted that soon some scientist would come up with a sort of spaghetti theory to explain how particles are attached to each other… (nanotechnology was not yet in the media, but now I call it the nano-spaghetti theory).
And there we are: I had predicted the string theory brought up recently by the Argentine physicist Juan Maldacenare of the CERN (and probably involved with the LHC) – and you may as well guess what I think of it…
How should you know, with the whole scientific community believing in these forces? I guess that this is so because scientists are afraid the simple explanation of gravity by impact forces would sooner or later get them out of work.
Repressive Authoritarian Physics Enforcement = RAPE (of the gravipushers by the gravipullers… it’s mathematical!)
Seriously: the total force of the gravitational push is only extremely slightly attenuated by the Earth’s mass knowingly constituted by an extremely filigree array of atoms – only a black hole would make up a 100% barrier.
Time to try an explanation of the intrinsic nature of the gravipushers.
Back to topic first: nobody ever mentioned the total potential energy contained in the boulder as could be liberated by nuclear fission.
Now, this amounts to explaining how the gravipushers are keeping together the atoms, i.e. how they keep the electrons on their orbits around the atom’s nuclei.
Imagine the nucleus of an atom acting as a shield against the gravitational push exerted on any one electron.
At any given infinitely short moment the imbalance between the gravitational push on the electron coming from the outside of the plane tangent to its orbit, and the gravitational push coming from the inside (nucleus side) of this tangent plane – due to the partial shielding of the push coming from the nucleus direction, by the nucleus itself – corresponds exactly to the centripetal force acting on the electron by virtue of 1) its mass and 2) its speed relative to the nucleus.
And here is a practical example based on a specific kind of particles, i.e. photons: imagine two bodies orbiting around the sun on two orbits of slightly different diameter, but on the same radius, i.e. constantly aligned with the sun. One of the bodies will thus constantly hide the sunlight from the other. The inner body casting shadow over the outer will then be pushed towards the latter by the outward flux of photons (i.e. the so-called solar wind some space scientists already envisage to use for interstellar travel by means of huge ‘sun-sails’.)
The preceding basics of gravity might also serve as an explanation of how matter might be created:
When two bodies of different masses encounter each other in directions corresponding exactly to the virtual tangent of a virtual orbit of the smaller body’s center of gravity around the bigger body’s center of gravity – so that at the infinitely short moment when the bodies simultaneously cross the line running through the centers of gravity of the bodies and perpendicular to the parallel planes respectively containing the two trajectories, the resulting virtual centripetal force acting on the smaller body (by virtue of its relative speed versus the bigger body and by its radial distance from it) corresponds exactly to the excess gravitational push on the smaller body as resulting from the difference between the push coming from the space side and the push coming from the bigger body’s direction as attenuated by this body’s shielding effect – the smaller body will be confined for ever within the circular “gravitational shadow” field virtually existing around the bigger body. This is of course also applicable by inverse analogy to the bigger body as orbiting around the smaller, yet on an orbit contained within the orbit of the smaller around the bigger.
This is a first attempt to show that no magic bond is needed to keep an electron on it’s orbit around the nucleus.
But now it’s time to go into finer details about the gravipushers:
First I have to explain my theory of the fractal hierarchy of the cosmos, with an infinite succession of ever smaller dimensional orders, according to a dimensional reduction ratio corresponding to the size of the sun system compared to that of the atom, where the atomic scale is the next lower fractal level in the hierarchy, and again the subatomic scale the next to this, and so on… infinitely (notice that nature doesn’t care for the infinite bewilderment and frustration this vision causes to your fragile psyche).
There is even more to come: Imagine that exactly the same infinite succession of fractal levels is extending outwards into the cosmos, which gives us a first sense of the double nature of infinity. Eternity is indeed made up of two eternities, one into the past and the other into the future… and so is infinite length: extend your left arm and imagine an infinitely long line in its direction, then extend your right arm in line with the left and imagine an infinitely long line extending to the right. There you are: infinite length is actually twice infinite length – infinitely troubling, and don’t you think you are in the middle!… where should there be anything like a center point on an infinitely long line? We’re just getting caught by Peters law of everybody striving to reach his or her own level of incompetence…
But we can infer a few interesting points from the vision of a fractal structure of the cosmos, e.g. why should there not be countless civilizations on countless electrons, with every civilization getting born, evolving and dying out in a matter of a few seconds, minutes or hours? With maybe even English being spoken in some of them? But that’s just the next inferior, i.e. the subatomic level. Imagine the number of such electrons within the infinite succession of ever lower-level scales in the fractal cosmos…
The ultimate conclusion would be that down there we have a situation where an infinity of particles are contained in an infinitely small space, causing an infinitely great number of collisions within an infinitely short laps of time after an infinitely short average distance of free travel, and that therefore an infinite number of events are happening all around us within an infinitely short lapse of time.
There you can see that at an infinitely small scale there is no more such thing as the particle shower I referred to in my initial explanation, but only infinitely small vibrations at infinitely high frequency. As to whether speed and/or the energy are also infinite, I tend to believe that there might be a limit to one or both.
To relax from these infinite mental constraints, let’s come back to the example of our air molecules: they travel at the average speed of sound over a measurable or calculable average distance before collision with other air molecules, and the pressure generated on any containment wall is made up by the number of air molecule impacts within a given time and by their individual mass and average impact speed and angle values.
In fact the air pressure on a body is not generated by an air molecule shower or rain falling onto the body, but from vibrations of air molecules impacting the body at an extremely high frequency, depending on temperature and density.
There may be a possibility to simulate an analogy with gravitation by opposing, in perfectly still air, two bodies of filigree structure analog to the atomic structure of solids (at the scale of air molecules versus cosmic particles), to maybe confirm the existence of a force pushing the two bodies towards each other (all electrostatic forces excluded – a rather difficult experiment, but wouldn’t it be worth 10 billion dollars, Mr. Higgs?).
As a conclusion, let’s look outwards into space, into the infinite succession of higher dimensional orders of the fractal cosmos, where the next higher order, i.e. the billions of known galaxies expanding (and according to more recent findings, also contracting in some galactic regions), might represent the movements of a gas, e.g. a fart expanding within a bowel (of which the wall would be outside of the reach of our telescopes) pertaining to an organism of unimaginable dimensions…
Well, and this is only the next higher dimensional level of the cosmos… yet there ought to be an infinite succession of them out there…
At an infinitely high dimensional level of the fractal cosmic hierarchy, all that ought to be left would be an infinitely small number of events happening within an infinitely long lapse of time… (remember that nature doesn’t care for your infinite bewilderment and frustration this vision causes to your fragile psyche).
And I can very well imagine the reaction of the average scientist to this mind-blowing illustration of infinity: “We know infinity is huge, but come on, buddy: not as huge as this, please…”
You’d rather trust Woody Allen’s definition then – remember?.. “Eternity is very long, especially towards the end.”
edivincison, please start a separate thread for your theories. Call it “Please criticize my theories”. What you’re proposing goes way beyond the subject of this thread.