I've heard and seen many different theories on perpetual motion. All of the devices I've seen do not work (obviously). In any event, I'd like to know if any one here thinks that perpetual motion is possible (or not) and they think so. Is it a matter of time before someone creates a device and proves everything wrong? Does such a device exist but scientists and government officials refuse to acknoledge it? What would happen if the world was introduced to a perpetual motion device?
If by perpetual you mean "as perpetual as the universe is" then I would say yes. It is possible. For example, tidal generators using the moons orbit are already in service. Not to mention solar power and wind generators. The perpetual motion devices you talk of need greater definition by you for any one to answer you question more thoroughly.
"There's no such thing as a free lunch." This is basically what the second law of thermodynamics says. One consequence is that it is impossible to build a machine which produces more energy than is needed to run it. This does not rule out all perpetual motion - only perpetual motion which claims to produce excess energy. For example, you might think of the motion of an electron around a hydrogen nucleus as perpetual motion. However, the energy of the electron is constant. You can't extract energy from this system without altering the electron's motion and reducing the overall energy.
@James R Hum, Would that be a perpetual flow of `energy` from high to low entropy? (and bearing in mind the Heidelberg uncertainty principle, er, or not, in a heat death ending)
If this perpetual motion were to create energy in the process then, by our physics today, it is impossible. This is so because it would mean we would have to rewrite thermodynamics theory which has worked exceptionally well so far!
First law of thermodynamics: conservation of energy. You can't get out of a process more energy than is put in. That's why such things as tidal generators, wind, and solar power generators work- you are accessing energy already in those. Although, I disagree with Quantum Quack's "as perpetual as the universe is". The earth itself isn't going to last that long! Second law of thermodynamics: there's always friction. In any real machine you aren't going to get as much energy out as you put in. Any machine will eventually wear out. (One of my favorites: a wheel with "weights" on the circumference. On one side the weights were marked "9" (pounds) but when they got around to the other side they were turned over and so read "6". Of course, the wheel always turned toward the side with the heavier weights!"
The electron isn't really in motion around the hydrogen nucleus, except in some kind of planetary, pre-quantum model. There is simply a wave of probability in the area around the nucleus. It is impossible to build a machine that continues to display motion, unless an external source of energy powers it. No self-contained unit can function forever, since it would eventually use up all of the energy that is powering it. This isn't a government conspiracy, but a basic rule of physics.
I would extend this a little by adding that according to our current understanding of physics. I would be very surprised to see us using the same laws 100 years from now.
Conservation laws correspond to symmetries in the universe, from Noether's theorem. Conservation of energy implies and is implied by the laws of physics not changing over time. Current measurements show the fine structure constant changing by less than about a part in 10^15 per year.
based on measurements taken over a 200 odd year span of time most of which are considerably more recent. Is this time span of measurements sufficient to inspire confidence in the interpretation of those measurements. Given the age of the universe? For example the universe may appear to be stable at present thus giving us these laws. But was it or will it remain this stable so as to allow us to write these laws?
An electric perpetume mobile? Put an anode and a cathode parallel in a vacuum tube, only microns apart. The anode is made of material that emits electrons very easily. The cathode is made of material that resists to emitting electrons. So the escaping electrons of the anode are caught by the cathode and not the other way around. When you short circuit it with a resistor, an electrical current should flow, producing electrical power. But where did the energy come from?
actually I argued this point a while back dealing with curved space ......if you fired a laser towards the front of you and it avoided hitting anything it would eventually hit you on the back of the head. Sounds absurd doesn't it
Brandon9000: Well, the electron has non-zero momentum and kinetic energy, so I'd say that means it is in motion. I agree with you that it doesn't orbit like a planet.
Two points: 1 - Most people misapply the term "Perpetual Motion". Perpetual Motion by definition is not possible. Perpetual Motion has nothing to do with extraction of power. It is a machine set in motion that remains in motion without external energy applied. In theory a perfect machine with no losses of any kind could meet that definition but would never be able to generate external energy without rapidly running down. 2 - Machines that do not need to be set in motion or that produce energy output, even perpetually are not perpetual motion. They would by necessity have to have a source of external energy, even an atypical or unknown one, i.e. - Should a gravity device actually operate and produce power it would not be perpetual even though it might run for as long as the universe continues to operate. It would have an unknown external energy input and hence would not be "By Definition" perpetual motion.
so by definition perpetual motion is impossible simply by definition. In other words if yo have a device in mind then what ever you do don't call it a perpetual motion device becasue what you are calling it is impossible. Why do we use this word perpetual in the first place I wonder?
Actually I have to back pedal just a bit. The following are two typical definitions. ***************************************************** 1 - Noun 1. perpetual motion - motion that continues indefinitely without any external source of energy; impossible in practice because of friction motion - a state of change; "they were in a state of steady motion" 2 - Definition: [n] a machine that can continue to do work indefinitely without drawing energy from some external source; impossible under the law of conservation of energy ***************************************************** It seems when you say simply "Perpetual Motion" The definition is as #1 above but if you say "Perpetual Motion Machine" they use the #2 definition.
so even if you constructed a machine entirely made of fixed magnets it would fail in that it could be argued that the magnetic field is generated by external sources ( at quantumm levels etc ) of even the creation of a machine theat depends on the ambience by default would fail as well energy vs no energy......
