Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Eagleon]

Wait a minute. Let me get this straight.

You guys are discussing the effects artificial gravity would have on the field of hydroelectric power generation?

It's no weirder than nuclear, which is just basically very advanced steam power.

No, more the effect it would have on conservation of mass/energy, if it is possible to make a generator that generates more power then is put into the system (obviously modern hydroelectric doesn't count because its powered by the sun essentially), then the law of conservation of mass/energy would be fundamentally untrue (as well as the second law of thermodynamics).

There's nothing in conservation of mass/energy that says there can't be some source we haven't discovered somewhere that could give us basically "free" energy. In this case, the system is merely larger than we previously knew, and we're not violating any conservation principles. The theory can always adjust - the one thing it's being battered by a little is quantum physics, and overall it's still held up pretty well even if only statistically

[thobal]

Well there's your problem right there! You're not discussing anything at all!

I remember someone else mentioning about how it would be a reaction-less drive. That might be interesting. But it begs the question, where does the energy come from? Worse, where does it go?

The thing about the second law of entropy that no one seems to appreciate is that it keeps everything from exploding.

So no, if you made a gravity generator it would use more energy(ie some would be lost as waste heat) than it would be able to impart on objects. If not, the universe would explode. (Or the machine would melt if you left it on for too long).

So remember, always give your perpetual motion machine time to cool off between uses.

Also, perpetual motion machines cause global warming.

Basically, you have to cool the machine because it's adding heat to whatever system you're in. So you need to expend energy trying to get rid of this heat. I would submit that the cooling needs of perpetual motion machines will require energy greater than the net energy gained via perpetual motion.

But seriously, a perpetual motion machine would eventually overheat the universe.

[Sean Mirrsen]

I'm thinking by the time we get to artificial gravity, we'll already be knee-deep in mass-energy conversion devices, so hydroelectric power won't be much more than a fun science fair project.

Also, perpetual energy machines can thus be used to prevent heat death of the universe.

And in regards to artificial gravity on a spaceship, specifically, I think the best way would be to just use a constant 1g acceleration, with the ship itself structured like a typical building, and the pilot lying on his back, in his chair, on the roof. With proper route planning, there would only be a brief period of low gravity as the ship turns around halfway to begin deceleration, and of course when coming into/leaving dock.

[thobal]

Also, perpetual energy machines can thus be used to prevent heat death of the universe.

Or it may accelerate heat death, because you'd have waste heat stretching space.

[Singularity-SRX]

I thought gravity was a force like magnetism? As in it just is.

[Durin Stronginthearm]

Basically, artificial gravity is one of those technologies that's probably not even as practical as, say, dyson spheres or the like... Actually we'll probably end up changing ourselves and what we need (food, etc.) to not need gravity before we even know what it is.

This. It's easier to completely overhaul human biology through genetic engineering than it is to manipulate gravity.

[GlyphGryph]

And in regards to artificial gravity on a spaceship, specifically, I think the best way would be to just use a constant 1g acceleration, with the ship itself structured like a typical building, and the pilot lying on his back, in his chair, on the roof. With proper route planning, there would only be a brief period of low gravity as the ship turns around halfway to begin deceleration, and of course when coming into/leaving dock.

Was this would Rama did? I forgot...

But I know I've seen it done in a couple places!

[DrPoo]

Generate a tiny, tiny PRETTY FREAKING tiny black hole, something of such a little volume its attraction would only make up the gravity of earth, i guess.. but we will never have such technology.

[Lagslayer]

An explosion would only occur if the energy was moving more or less randomly. If we can get all the energy moving in the proper direction and at the same time, things like artificial gravity and light speed (and by extension, greater than light speed) travel should be possible. Both of these, light speed in particular, would take massive amounts of energy, but If we have a way of storing it afterwords, we would only lose a bit and only have to generate the bulk of it once (a little bit would still be lost to heat or something because the system would not be 100% efficient). Also, the energy would have to be distributed properly so the object isn't torn apart from parts of it moving faster than the rest.

[Durin Stronginthearm]

An explosion would only occur if the energy was moving more or less randomly. If we can get all the energy moving in the proper direction and at the same time, things like artificial gravity and light speed (and by extension, greater than light speed) travel should be possible.

No. You can't get background heat moving any way but randomly, that's essentially what entropy is - energy that cannot be used and carries no meaningful information.

Both of these, light speed in particular, would take massive amounts of energy, but If we have a way of storing it afterwords, we would only lose a bit and only have to generate the bulk of it once (a little bit would still be lost to heat or something because the system would not be 100% efficient). Also, the energy would have to be distributed properly so the object isn't torn apart from parts of it moving faster than the rest.

No, anything moving at lightspeed has infinite mass, so to accelerate anything with mass to c requires infinite energy. It doesn't matter how you play with the concepts, that's how it is.

[Lagslayer]

Saying something, anything, moving at light speed has infinite mass assumes light moves infinitely fast and/or light has no mass, neither of which is true. We know the speed of light in a vacuum is approximately 299,792,458 meters/second, debunking that light is infinitely fast. Energy is the motion of matter, and light is no exception. Even light is affected by gravity because the movement is connected to a particle. Normally you wouldn't notice this, but something with exceptional gravitational pull, like a black hole, makes it obvious. Also, the fact that light travels slower when other matter gets in the way adds to this.

If you are on a plane going 400 mph, you can stand up and throw a ball in the air. Neither you nor the ball is going to slam into the back of the plane because the plane and everything inside of it is moving together. Light travel would be basically the same as this, just moving faster. The only difference is that a light speed craft would likely not be using a propulsion system like we have today.

Also, assuming heat cannot be made orderly raises a new problem. If existence has existed forever, then all energy would be heat by now. Unless you are saying that one day everything sprang into existence from nothing, which also makes no sense. Everything comes from something. We just don't know how to make heat become orderly again without losing even more energy to heat. By extension, I propose that before the "big bang" was another big bang. A huge mass explodes, releasing all the matter and energy. this matter and energy combines into stars, planets, whatever. Slowly, gravity starts pulling everything back together. When the mass gets too dense, it can no longer contain the energy within and explodes. Then it starts all over again, and who is to say that there weren't other big bangs in the universe. Everything goes in cycles when you get down to it.

[SniHjen]

the above post is bollocks.

Light does NOT have mass.

in fact: light NOT having mass is the reason it moves at lightspeed, if it somehow could be slowed down, it would cease to exits.

[alway]

Yep, light not having mass is also the reason why gravitation affects photons differently than other particles. Normally, a particle slows down. Light, however, can not slow down. It has a constant speed, no matter from what perspective or velocity you see it. This is THE fundamental principle of relativity. Einstein explains it much better than I could hope to: http://www.gutenberg.org/cache/epub/5001/pg5001.html
Light in a gravitational field merely has a shift in the energy of the photon as its wavelength changes.
You can't travel at the speed of light any more than you can tell me what tangent of 90 degrees is: it's an asymptote.

[GlyphGryph]

If light doesn't have mass, how is it that it's effect by gravity?

Here's the thing, if your assuming things moving at lightspeed have infinite mass, you are using the principles of relativistic mass. If you're using those principles, light has mass.

If you're not, and using the more mundane definition of mass, of course it doesn't. But then something moving at light speed DOESN'T increase in mass at all, so the whole argument is pointless.

[Il Palazzo]

Lagslayer and GlyphGryph - and it's not meant to offend you, if you can believe that - not understanding something doesn't mean it's stupid.
If any of you is thinking that they're smarter - because you must be if you've noticed a problem that they must've missed - than Einstein, Planck, Feynman, and the rest of professional physicists responsible for our current understanding of nature, then go ahead and say so out loud.