h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

If a train is travelling at 50 mph and I run down the train at 10 mph, my ground speed will be 60 mph.
Therefore, if I'm in a rocket travelling at the speed of light and I turn on a light in the rocket, although the speed of light is just that inside the rocket surely, outside and relative to say a fixed point light is now travelling at twice the speed??? or have I got this wrong.

Well, it does sound logic, but im no expert. Ask Einstein

If the light is contained within the ship it will bounce
around inside at its usual speed.

But if you had headlights on your spaceship the light would
just bunch up on the front and create drag.



~jwf~

Ok, maybe you should send this to the NASA and see what they think about it ?

Hi soulman, nice to have such an interesting question. Your logic is sound but light cares not for logic. Light farts in the general direction of logic, light makes jokes about logic in a language logic cant understand and makes rude hand gestures when loic isnt looking.

If you are on the ship you would see light travelling from its ource at the spped of light, not because logic says it will but because that's the pysical construction of the universe. Physics has shown us how light changes if the object emiiting the light is travelling towards the observer or away from the observer, but that it still travels at the same speed relative to the observer.

Its all very complicated to explain (well too complicated for me to explain) but does fit with the laws of physics very neatly. Someone whose more comfortable with this subject will be along soon to make it all crystal clear.

Here you go this should explain some of what you want to know.

http://www.youtube.com/watch?v=V7vpw4AH8QQ

A very good video and does go someway to explain things. I know about red & blue shifts in light, if it's moving away or towards you, but in my question, i'm assuming that it is moving in parallel to the obsever and I'm picking a point just as it passes. The laws of physics are sound and the light (I'm only looking at the photons going forward) are going at light speed as everything is relative within the ship. So assuming the ship is at light speed, the light (going forward) within the ship must then be in the future (according the the video) or are they?

I don't think any laws of physics are being broken in this example but I am interested in, that one light photon, within the ship, that's going at light speed within a ship going at light speed. The headlights outside the ship do not apply here as that assumes light being emitted externally and the ship catching up to it's own beams.

Any rocket scientists on here?

Einstein he say....

"Thou shalt not add thy speed to that of light...."



QED!



GT