J.C.MacSwell

Maybe Spaghetti Theory will take over String Theory (Macaroni metrics, Lasagna branes etc. etc.)

the next generation of peltier effect materials sounds promising, (unlikely to rival compression pumps on efficiency though)

if you really wanted to save money on air cond, route the radiator of your fridge outside.

 

with maxwells demon, he can probably work on a scale big enough to avoid the uncertaincy principal, the radium(?) atoms had to be cooled extremely close to 0 K for the effect to become apparant. im sure he could take an approximate enough estimate of speed to open a hole in the right spot, hell, give him a fudge factor, a band of momentum where nothing gets through either way.

I'm pretty sure if you include the uncertainty of the demon himself he cannot get an edge over random statistical variances. (someone summed up the laws of thermodynamics as "You can't win, you can't break even, but you must play the game")

antimatter is chemically indistinguishable from normal matter if you ignore the nasty effects of matter and antimatter colliding so yes the universe would be the same.

Other than the CP conservation violation Swanton mentioned.

Forgot where I ready this but if you are off galavanting around the universe and meet your "twin", and he offers to shake your hand, if he offers the left hand don't shake it!

Actually, I meant why do we conclude the 1:1 ratio of particle / antiparticle since there is very little antimatter. I wondered if perhaps the math suggested this.

 

From what I understand, we can generate antimatter in small quantities - for quite the price I hear.

I think we conclude otherwise, but wonder how it came about. AFAIK "every particle has an anti-particle" refers to the type of particle not the quantities, although any new production of one must be balanced by the other.

Isn't there also a small "flaw" in the conservation law that in theory biases matter over anti-matter?

I know generally physics prevents the demon existing, or says that when you analyse the whole system the entropy does increase, but what specifically does QM have against it? Sure it would make the demon's job harder, what with quantum tunneling, but why does QM actually forbid it?

IIRC it is based on the uncertainty principle. On the scale the demon needs to operate he can't have the information he requires.

On a more pedantic level, would it not also reuslt in an imbalance of pressure? At some point, won't the demon be having to hold back a whole pile of molecules all trying to push in one direction?

At the size of the Demon it's not pressure, just momentary impacts. Also will not work according to Quantum physics.

The thought experiment demonstrates the statistical nature of the second law.

Basically because you are using the reservoir for free, and only paying to run the pump.

Yes, and entropy increases but not by as much as if you had used a conventional electric heater at "100%" efficiency.

Not only would running an AC backwards use more energy than a plain heater, but it would barely work. The heat energy has to be pumped from outside, which means the AC has to be colder than the outside, which means it wouldn't work when it was needed most!

 

Now, what you really want is Maxwell's Demon.

Even if plain heaters are 100% efficient, which they basically are, heat pumps can deliver many times more energy than they use (pay for). Entropy increases as the high grade electrical energy is used to concentrate the much lower grade heat energy outdoors to not much higher grade room temperature. It is much more efficient (and less heating required anyway) the warmer the outside (or geothermal, lake water etc.) temperature.

Note that heat pumps can claim to be 300% and greater efficient, which is true, but that is not thermodynamic efficciency, just that it delivers more heat than the energy that it uses directly.

How can you have a sphere if the black hole is rotating? The planets orbit in a plane because stars spin. Black holes come from stars, so they rotate.

It should still collapse to a point.

the wing in the lower layer serves the same anti-slippage function as the keel of a sailboat or the wheels of a landyacht, or the skates of an Iceyacht.

 

I'm an ex senior National champion in landyacht design and racing (20 years ago age 16) so I'm pretty experienced in the mechanics of sailing at 5 times windspeed with a crude cloth sail. Iceyachts achieve better.

If the upper foil is in a 200kph+ jetstream and the lower in the troposphere then I wouldn't want to postulate that supersonic sailing is impossible.

I'm a dinghy and iceboat racer. My first thought was that you had no energy potential to harness unless you were somehow in contact with the ground or another fluid, air or wind, at a different velocity. I just didn't realize this is what you were suggesting. You could actually go "upwind" of both "winds" using this metod, at least in theory. Interesting idea. It would be an awkward contraption though.

I spoke briefly with Lee Smolin yesterday. .

I hope he appreciates your efforts!

You do have a net momentum, though, if you look at it this way: you are using a buildup cavity. If you keep adding photons from one direction, you will have E/c more momentum in that direction for each photon you add. At any given time, then you will have something like E/c * Q (Q is going to be related to how many photons you can get onto the cavity) If you can use all of those photons for propulsion, you will get an instantaneous force like the guy has claimed, but only over a very short distance, because you'll drain the cavity in doing so. (and in a time of 2L/c, so a 15 cm cavity will drain in a nanosecond) The analogue would be (similar to what YT suggested) a pressurized container, like a bucket or hose, that is suddenly uncapped.

 

As I said before, it will not be any more of an impulse than ejecting the photons directly, since you will have losses over time in any cavity. There may be some practical reason to do it in one shot; all you are doing is storing up the energy.

Understood, except I don't think that is what he is claiming. Also 99.99% of the energy leaves with the photons, not going into propulsion. Extremely inefficient.

I think he is claiming that the shape of the chamber influences the net rebound/impulse of the continuously resonating photons. An analogy would be putting a boat in the water and it moves forward because of it's shape.

bit of an interesting and probably feasible idea.

Done a fair bit of design feasibility analysis on this over the last decade.

Not much chance I could commercialise the technology in the forseeable future so happy to discuss in the public view and interest.

 

IMO these could be safer, more reliable and possibly as fast as jet Airliners.

Any attempt by the plane to harness the energy of the wind will cause more drag than thrust unless it is a tailwind (in which case lift will be somewhat problematic)

;304196']

 

Here's a question though: I am learning relativity in university right now' date=' and that it agrees with conservation of momentum. This drive seems to violate conservation of momentum. Does it really? Or is there a way around it using relativistic principals?[/quote']

 

Yes it violates conservation of momentum. No way around it using relativistic principals.

 

 

It won't work. If it did he would be smart enough to realize this. He would be saying he has a new drive that violates relativity instead of claiming he is using relativistic principals.

That's good news!

I have that one but haven't read it. Are any of the roads extra dimensional or is that too stringy?

I Wonder if TWP is actually helping Elegant sales?

No, you're all wrong, but I'm too busy to explain. But take it from me, you're all wrong. (even the original poster who was just asking, he's wrong also in a different way but I doubt you'd understand if I told you why)

Glad I could help.

Yes. Anything noticable would take a billion years, and if the moon slows down, it moves farther away, not closer.

Correct, but drag on the moon speeds it up not down, though I have heard the moon should eventually escape (on a thread here, can't remember which one or why it escapes)

Oh good, more greenhouse gas. Gotta love carbon...cough...cough.

I love it. And somewhat appropriate' date=' given the chaos of taxonomy and eventual downfall of Pluto that it in large part caused.

 

As for the moon, well, "nomon" can mean law, name, custom, or conventional wisdom. This moon, then, is symbolically without and against those things, appropriate for one so utterly remote from light and the ways of man.[/quote']

 

Naw, it's just that he had a falling out with Lucy Lawless. So he took away the name Xena for the planet and named the moon Lawlessness.

Yes, that's more or less how I understand it. I could be wrong, but I don't think so.

Good, I think that was Spyman's point also. More on this later (anyone know definitively what GR would say on this?) but I like your view of the expansion or contraction as nothing actually moving (local movement aside) which is also how I picture it from an "outside" POV.

This brings us back toward my original question about the momentum of the expansion.

Since "nothing is actually moving" what keeps the expansion going? What tells space to keep expanding at the same rate?

Assuming gravity can only change the rate incrementally over time from the present rate the main factor that determines tomorrows rate is today's rate, the present "momentum" of the expansion.

Because the collapse is not all stuff moving together. Technically, nothing is actually "moving" at all. It's just getting closer,[/i'] since space itself is shrinking.

It's getting closer because it is yielding to gravity.

I think I see what you are getting at with regards to direction though by your "nothing is moving at all" comment. You are only considering the effects of nondirectional yielding to gravity to affect (or coincide with) a shrinking of space. (Am I reading you correctly?)

It should hold for general relativity, too, unless I'm being stupid. Moving stuff [/b']around xyz-coordinates shouldn't change the metric.

Then why would space collapse when all the stuff gets moved together?

I think GR predicts this whereas Newtonian physics does not. It is like the potential energy of mass displacements supports what space "is".

So the one small ball drop (and Earth "dropping" immeasurably toward the ball) is one small "tuck" (much much smaller than the immeasurable Earth displacement) in the fabric of space.

I think this is the source of the confusion. The answer is no' date=' since the Earth-ball system has not become any closer to everything else[/b']. There is still the same overall density, despite this gravitational collapse, since there is just more empty space around it.

 

Analogously, if I move all the furniture in this room into one corner in a big pile, I've greatly increased the furniture density in that corner. However, I haven't made the room any smaller, and I haven't affected the overall furniture density, since its the same amount of stuff in the same space.

Newtonian/Euclidean this is obviously right.

From my understanding a Big Crunch would be like the Big Bang but in reverse' date=' any locally movement would not make any difference.

 

There is no known escape path for a powerfull spaceship, it could take off in any 3D direction but still be caught in the crunch.

 

If it would be similar to your local ball drop then the beings on the little blue ball should be able to measure in which [b']direction[/b] they are moving and the speed caused by the expansion/collapse.

If the sum of all masses collapsing gravitationally add up to a collapse of space, would not a small insignificant gravitational "collapse" coincide with an immeasurable reduction in space. (relative to if the event had not happened and all other things being equal)

Edit: and if this is correct, what does it say about space?

Gravity seems to balance out in the 3 apparent space dimensions and all mass seems to "escape" the insignificant dropping of a ball so I'm sorry but I am still missing your point.

Don't give up on me though!