36 replies to this topic

[Dauth]

Huge amounts of water, heated to steam and used to drive a generator (as a guess) 2.2MeV is tiny tbh but enough source atoms will push the power output up.

[Rich19]

Dauth, on 6 Feb 2008, 17:09, said:

Firstly http://forum.cncrene...showtopic=18953

Secondly, Cherenkov postulated particles faster than the speed of light in certain media.

Light travles at c (3*10^8 ms^-1) in free space.

In air it's a bit slower, water slower still. however in water it's possible to give an electron enough energy to move faster than light in water. In this case Cherenkov radiation is emitted.

Another way is the expansion of space in the early universe, while something can't travel faster than light in free space, if the space itself is expanding, nothing in physics can stop it.

Proving the claim would be something to watch, since it would indeed cause a black hole...

Cherenkov radiation is probably quite familiar to forum goers here - if I remember rightly it's the cause of the glow that comes from nuclear reactors. So when Tao talks about "Tha glow! Tha wondafool glooow! Can you no see it general?!", he's referring to faster than light electrons in water.

Edited by rich19, 07 February 2008 - 20:26.

[Dauth]

Its possible in nuclear reactions, and it is a wonderful glow, is a light based sonic boom.

[smooder]

Dunno where the proof is but apparently there is a theory that in something called Metaspace (i think) Energy of life is attracted to it and when it leaves the body it goes there faster than light. Maybe someone can explain this better I diont know...

[Dauth]

Sounds like a K-space or phase space, its where physicists send part of a wave that doen't happen in relaty but makes the maths convenient.

[CodeCat]

Whoa hold on hold on. Your mass does not increase the faster you go. That's a common myth. Because movement is relative, and relative to yourself you're always stationary, you will never feel your mass increase if you go faster because there is no moving reference point with respect to which you're going faster. In fact, all your laws of physics will stay as they are no matter how far you push in the accelerator of your starship.

What happens is that an outside observer who is watching you will see you move past at almost the speed of light. As a result, he will see you blue-shifted as you move towards him, and red-shifted as you move away. In addition, because of your immense speed he will see your length significantly reduced in the direction of motion. The effect of this is that the faster you think you are going, the shorter you become to an outside observer. To think of how this makes sense, consider this:

- First, you are travelling at 100 times the length of your space ship per second (let's assume it's a really really big space ship) as seen from the ship's (i.e. your own) reference frame.
- Then, you accelerate to 200 times the length of your space ship per second as seen from the ship's reference frame.

An outside observer will see the same. Indeed, first you were going at 100 lengths per second and afterwards you will be going at 200 lengths per second. However, because your ship also got shorter to the outside observer, what actually constitutes a length has become smaller itself. So while you are now moving at 200 lengths per second, your ship has gotten shorter and as a result your actual speed as the observer sees it is LESS THAN TWICE it used to be. In fact, as your speed approaches the speed of light, your ship will hardly appear to accelerate at all to an outside observer, but instead it will just get shorter and shorter. So in effect it is still accelerating in that it is covering more and more times its length in one second, but it's not really covering more distance.

[Nakamura]

CodeCat, on 7 Feb 2008, 23:18, said:

Whoa hold on hold on. Your mass does not increase the faster you go. That's a common myth. Because movement is relative, and relative to yourself you're always stationary, you will never feel your mass increase if you go faster because there is no moving reference point with respect to which you're going faster. In fact, all your laws of physics will stay as they are no matter how far you push in the accelerator of your starship.

What happens is that an outside observer who is watching you will see you move past at almost the speed of light. As a result, he will see you blue-shifted as you move towards him, and red-shifted as you move away. In addition, because of your immense speed he will see your length significantly reduced in the direction of motion. The effect of this is that the faster you think you are going, the shorter you become to an outside observer. To think of how this makes sense, consider this:

- First, you are travelling at 100 times the length of your space ship per second (let's assume it's a really really big space ship) as seen from the ship's (i.e. your own) reference frame.
- Then, you accelerate to 200 times the length of your space ship per second as seen from the ship's reference frame.

An outside observer will see the same. Indeed, first you were going at 100 lengths per second and afterwards you will be going at 200 lengths per second. However, because your ship also got shorter to the outside observer, what actually constitutes a length has become smaller itself. So while you are now moving at 200 lengths per second, your ship has gotten shorter and as a result your actual speed as the observer sees it is LESS THAN TWICE it used to be. In fact, as your speed approaches the speed of light, your ship will hardly appear to accelerate at all to an outside observer, but instead it will just get shorter and shorter. So in effect it is still accelerating in that it is covering more and more times its length in one second, but it's not really covering more distance.

I must say that these are very good ideas, but there's a problem at the very beginning.
If you're accelerating than you'll need some energy. And because the energy is equiwalent to mass, your mass will become more and it'll take more energy to accelerate your ship (or whatever you want).

[Medve]

Necro much?

Medve

[CodeCat]

Necro is allowed if it brings in new discussion material that is relevant. That's the case here.

Now to answer Nakamura. Yes, mass is equivalent to energy, but that does not mean it IS energy. The mass your body is made up of isn't exactly very energetic. If you wanted to get the energy out of it, you'd first have to remove the mass. Therefore mass is equivalent to energy, but they never exist as both energy and mass at the same time.

[Nakamura]

CodeCat, on 18 Mar 2008, 1:05, said:

Necro is allowed if it brings in new discussion material that is relevant. That's the case here.

Now to answer Nakamura. Yes, mass is equivalent to energy, but that does not mean it IS energy. The mass your body is made up of isn't exactly very energetic. If you wanted to get the energy out of it, you'd first have to remove the mass. Therefore mass is equivalent to energy, but they never exist as both energy and mass at the same time.

Sorry for the necro again but I forgot to answer.
Isn't it the increasing kinetic energy of the accelarating mass wich increases the m0 mass of the object?

[Dr. Strangelove]

SolidSpartan117, on 6 Feb 2008, 22:28, said:

Ok then, that put me in my place (Bows down to genius), but all I am trying to say is light is light and doesn't slow down ever.

Actually, in certain conditions(a Bose-Einstein condensate), light can stop.

[CodeCat]

Light definitely slows down. In fact, the slowing down of light is what makes lenses work. The refractive index is a measure of how much slower light travels inside the material. Pure vacuum has index 1, and denser materials have indexes higher than 1 (meaning slower).