Physicists: My theory of obtaining lightspeed!

Lagz · 26 Oct 2006 at 01:10

eXSBass said:
Introduction
During the explaination, please relate to the diagrams!
Now if the space ship can emit enough light from the (coincidently, I call them) sublight engines, then using conservation of energy, the ship should move really fast

No, all the energy is in light form, and it bounces off the wall and into space.

eXSBass said:
This occurs because the photons collide into the solid mass, but the solid mass doesn't move, so the ship does, as said in the conservation of momentum

Momentum requires mass, so firing photons (which have extremely low mass) isn't going to do anything. You would be better off sat in your rocket kicking footballs at the wall.

eXSBass said:
, by Newton!

Newtonian physics don't apply at high speeds.

locutus12 · 26 Oct 2006 at 01:12

i thought of an idea that would work to get to mars and back in less than a day(at a guess), the problem is it would cost trillions and take a centuary or more to build

its nothing special and uses technology at our disposal right now.

Raymond Lin · 26 Oct 2006 at 01:15

What about the constant acceleration, it must take decades or centuries to accelerate to light speed (lets pretend you can actually reach there). If you can actually accelerate to light speed in a short time, imagine the G force, anything that isn't nailed down would be crushed by its own weight in an instant won't it?

MasterMike · 26 Oct 2006 at 01:16

locutus12 said:
i thought of an idea that would work to get to mars and back in less than a day(at a guess), the problem is it would cost trillions and take a centuary or more to build its nothing special and uses technology at our disposal right now.

Been watching Contact?

Raymond Lin said:
What about the constant acceleration, it must take decades or centuries to accelerate to light speed (lets pretend you can actually reach there). If you can actually accelerate to light speed in a short time, imagine the G force, anything that isn't nailed down would be crushed by its own weight in an instant won't it?

According to the superbly scientifically accurate movie Event Horizon, anyone can survive such massive g-forces by floating in a tank of goo. I think this is correct.

Raikiri · 26 Oct 2006 at 01:18

Raymond Lin said:
What about the constant acceleration, it must take decades or centuries to accelerate to light speed (lets pretend you can actually reach there). If you can actually accelerate to light speed in a short time, imagine the G force, anything that isn't nailed down would be crushed by its own weight in an instant won't it?

He must have forgot the inertial dampers :rolleyes:

Minto · 26 Oct 2006 at 01:19

Lagz said:
Momentum requires mass, so firing photons (which have extremely low mass) isn't going to do anything. You would be better off sat in your rocket kicking footballs at the wall.

wrong. when m=0 E=cp (p=momentum c=speed of light e=photon energy)

also by radiation pressure the photons would give a change in momentum
moementum=energy of light pulse/speed of light

locutus12 · 26 Oct 2006 at 01:19

MasterMike said:
Been watching Contact?

According to the superbly scientifically accurate movie Event Horizon, anyone can survive such massive g-forces by floating in a tank of goo. I think this is correct.

no, its nothing like that... but it seriously would cost trillions of pounds and take decades to build it. its huge.

lay-z-boy · 26 Oct 2006 at 01:24

Fear not NASA, exs is here!

Moving spaceships at lightspeed = impossible.

Would be cool though, time stops at lightspeed (according to my physX teacher anyway)

locutus12 · 26 Oct 2006 at 01:28

the theory of relativity hinges on the fact that all light, everywhere, is at the same constant speed... one problem... its not.

http://www.newscientist.com/article.ns?id=dn2796

http://www.newscientist.com/article/dn6092.html

they also recently found that light slows down as it approaches the center of a black whole. the theory of relativity has been under increasing pressure for the last 5 years now and may have to be reworked in the long run.

Raymond Lin · 26 Oct 2006 at 01:32

Raikiri said:
He must have forgot the inertial dampers

So until someone invents that out of science fiction, going to light speed would be suicidle :eek:

daz · 26 Oct 2006 at 01:34

locutus12 said:
the theory of relativity hinges on the fact that all light, everywhere, is at the same constant speed... one problem... its not.

http://www.newscientist.com/article.ns?id=dn2796

http://www.newscientist.com/article/dn6092.html

they also recently found that light slows down as it approaches the center of a black whole. the theory of relativity has been under increasing pressure for the last 5 years now and may have to be reworked in the long run.

While the peak moves faster than light speed, the total energy of the pulse does not. This means Einstein's relativity is preserved, so do not expect super-fast starships or time machines anytime soon.

Also, the other article doesn't seem to suggest that relativity is broken either.
Remember, special relativity deals with observers in inertial frames of reference.

lay-z-boy · 26 Oct 2006 at 01:37

locutus12 said:
*snip*

in that case all we have to do is speed up light so we can travel faster without requiring more energy/gaining mass.

yer_averagejoe · 26 Oct 2006 at 01:38

MasterMike said:
No relativity involved - as your ship gets quicker, it will require more and more light to be emitted from it as its mass increases as it approaches lightspeed. If it were ever to attain lightspeed, it would have an infinite mass, which would require infinite energy to move it, and is therefore impossible.

Not to mention that this is the biggest of many reasons why this is an extremely flawed concept, but I'm sure someone who didn't drop out in their second year of astrophysics at uni will explain it better than I can now.

what....?

simply put, to reach the speed of liht, an infinite amount energy will be required.

I don't know if this is a joke thread as i can't be botthered rwading the rest and I am, at the moment uite drunk.

Minto · 26 Oct 2006 at 01:40

locutus12 said:
the theory of relativity hinges on the fact that all light, everywhere, is at the same constant speed... one problem... its not.

http://www.newscientist.com/article.ns?id=dn2796

http://www.newscientist.com/article/dn6092.html

they also recently found that light slows down as it approaches the center of a black whole. the theory of relativity has been under increasing pressure for the last 5 years now and may have to be reworked in the long run.

the first of those articles is talking about the group velocity of the wave, not the phase velocity. Reletivity only limits the phase velocity and hence it in no way vialoates it.

The second article is based partially on astronomical data, which is renown for its innacuracy, and in part on re-interpretation of old results. In addition a change in the fine structure constant does not mean a change in the speed of light. Planks constant and the electron charge also determine the fine structure and could equally have changed (though the electron charge changing does seem unlikely)

locutus12 · 26 Oct 2006 at 01:42

lay-z-boy said:
in that case all we have to do is speed up light so we can travel faster without requiring more energy/gaining mass.

vibrating photons at a certain pitch might do that

how youd do it is another matter...

daz said:
Also, the other article doesn't seem to suggest that relativity is broken either.
Remember, special relativity deals with observers in inertial frames of reference.

i didnt say it was broken

its just been taking a bit of a beating of late.

lay-z-boy · 26 Oct 2006 at 01:46

locutus12 said:
vibrating photons at a certain pitch might do that how youd do it is another matter...

Leave that to exs and his uber torches

Minto · 26 Oct 2006 at 01:48

locutus12 said:
i didnt say it was broken its just been taking a bit of a beating of late.

its really not. The first of those articles is virtually nonsense. They just found a way to speed up the group velocity so fast it can't carry information. The second is a vague dig at relativity at best.

MasterMike · 26 Oct 2006 at 01:48

yer_averagejoe said:
simply put, to reach the speed of liht, an infinite amount energy will be required.
.

Yes, you are drunk.

Yes, that is a good contraction of what I was trying to explain.

yer_averagejoe · 26 Oct 2006 at 01:50

MasterMike said:
Yes, you are drunk.

Yes, that is a good contraction of what I was trying to explain.

ahh rubbishness,i wish i wa sss sober enough to take an active part int this conversaton. i really do have a good amount of input. be back tomorrow if this thread is still alive

MasterMike · 26 Oct 2006 at 01:51

yer_averagejoe said:
ahh rubbishness,i wish i wa sss sober enough to take an active part int this conversaton. i really do have a good amount of input. be back tomorrow if this thread is still alive

Drink a pint of water, then go to bed