Originally posted by quango
Doesn't that mean we could theoretically launch a ship, and then launch a ship from that ship, and launch a ship from that ship, etc, to attain incredible speeds?

Incredible speeds? Yes. But it'd just be faster to have one ship have a larger fuel source. This is the whole concept behind the xenon engines. Whilst they don't have much push, the acceleration IS constant, and will last for a long time - which makes it in the end go faster.

The only problem with most ships is that they don't have the fuel capacity - and even if they did, stocking them with enough fuel would be pointless.

That, and you could achieve incredible speeds, but you still wouldn't hit light (even though every time you got closer to it, you wouldn't slow down, it's that your acceleration would be less from an outside observer).

And Viendin, your very right. I don't normally go into how you would percieve time to change and all that. Though there's a fun example for that as well.

I'd like to see the way in which you answer this. Imagine that the speed of light is 2m/s. You can walk at 1m/s, and there is a conveyor belt that moves at 1m/s. Whilst we both know that you can't travel at or past the speed of light (2m/s), what would be percieved by the travellar, and what would be percieved by outside observers, when the travellar walks on the conveyor belt in the same direction it is moving?

Exactly the same thing would happen as if there were a conveyer belt that moved .5*299,792,458m/s and I could walk that speed.

I would observe the conveyor belt to not be moving in my frame. I would then move at 1m/s forward, perfectly within physical limits of space and time. I would not notice anything out of the ordinary, unless I was simultaneously measuring the world around me, because it could appear that the whole world would slide together along the vector of the direction of my travel. It wouldn't slide right together, just become more .. erm, "densely packed".

Someone from off at the side would undoubtably observe you moving very fast, by their terms. They would see you, albeit, a more 'densely packed' you, moving along the conveyor belt at .. this is where it gets hazy for me, if you were actually moving at 2m/s then they would just 'see' a beam of light, in all likeliness, but, if you were moving 1.9999999m/s, then they would likely see you moving very, very fast.

The problem is, I'm no expert on this. I've just got a slightly above-average understanding of it from .. well, the masses. I can't really give definitive answers to anyone but them.

I don't really know anything about General Relativity, and that covers acceleration. I feel that I'd need to know it to properly answer this.

Sorry!

Well you may not, by your own standards (though I doubt by other's), get General Relativity - but you got your Special Relativity down pat!

Yeah, people would see you going almost, but not quite, 2m/s - and in fact would see you as if time had slightly slowed down for you. Alternatively, you would see yourself going at 1m/s, but (assuming you can see around you), you would see everyone else moving at a bit faster pace than they should.

The real deal is that you would also see them slowing down (if we count that you're travelling at almost, but not quite, the speed of light, and so can't really see well around you) - but that once you get off the conveyor belt, they would very quickly "snap" back to where they actually are (as the light catches up to you), whilst people ahead of you suddenly go from seemingly moving very fast (since the light from them reached you sooner), to slowing down (since light is now once again coming at you at a normal pace).

Ah, physics.

Originally posted by quango
Doesn't that mean we could theoretically launch a ship, and then launch a ship from that ship, and launch a ship from that ship, etc, to attain incredible speeds?

That sounds like a multistage rocket. It has been done before, but not to reach incredible speeds, just to maintain a near constant speed for a certain a certain amount of time.

Originally posted by sardion2000
It may be. When Solar Flares happen why do Neutrons arrive at the detectors before the photons?

You have any source for this? This would highly surprise me. What I have heard of are neutrinos expected to arrive before photons in the event of a supernova, because neutrinos have almost no interaction with matter and hence leave the core of the collapsing star immediately, while electromagnetic waves are absorbed and reemitted meaning that the speed in the star itself is lower than the speed in vacuum. This hasn't been measured yet though. Another possibility is that neutrons are formed before noticable (visible or otherwise) radiation is emitted, not that neutrons are actually faster than light.

[edit on 4-2-2006 by Simon666]

If you were in a spaceship travelling at near lightspeed and shone a light beam in your direction of travel, you would notice nothing at all different about the light.
If a stationary observer (not on the ship) saw this, he too would measure the speed of your beam at lightspeed.
The speed of light is always the same, independant of the reference frame of the observer.

Harte

The problem isn't seeing whats in front of you, the light we see on earth has been traveling for a long time to reach us too, the objects ahead of you have been reflecting light a long time before you happen upon them too, so there will be "old" light coming from them.

The problem is knowing exactly where you are and being able to callculate your relative position to whats ahead taking all things into account.

The real question about lightspeed travel that remains imho, is that, when you travel at the speed of light (which would require infinite energy and give you infinite mass), and you impact photons coming at you at the speed of light, won't the energy with which they impact your ship be infinite too?

Lightspeed travel is something we should waste time on, there are to many infinites wreaking havoc on us when we do.

Warp, hyperspace, subspace and wormhole travel are the only things we should look at, actual light speed travel is a waste of time.

Btw, did you know that theoretically, with warp travel, your actually standing still?

Originally posted by thematrix
Btw, did you know that theoretically, with warp travel, your actually standing still?

Fascinating, i must admit subluminal theory has always went over my head, i do not think i have the mind for it, could you explain the standing still warp theory, if you don't mind.

With warp travel you create a space/time bubble around your vessel and motion is obtained by manipulating its shape and density. Inside the bubble things don't move, its the space/time bubble you created, in which you are contained, that moves trough space.

You obtain motion by making space time more dense on one end and less dense on the other, warping the fabric of space/time (hence the name warp travel)

The inside of the bubble stands still because you could consider it a separate pocket of space/time, decoupled from the universal space/time.

Have you ever seen a bubble of water float on a pool of water? This usually happens in the bathtub when there is soap to create a film around the bubble which keeps it afloat for a while. Thats kinda how you separate yourself from the universal space/time when creating a warp bubble.

Hope that explains it, else I'll try to have another go trying to put the science behind this in non scientific words. (something I suck at :p)

No it's all good i got the general just of it, it all sounds horribly complicated mind you

You would see stars but arrive very quickly.

Say you were going to the nearest star system, wait the
astro nuts saw no stars on the Moon.
Only the Earth.
OK, then you would see the Earth and Sun get small very quickly.

Sideways the scene might be the same, that is if the astro nuts are liars.

Originally posted by Frosty
Yes, and that is how Einstein came to the conclusion that a person cannot travel at the speed of light.

Well if this is how were going to play the game it is also the way he proved that we are already travelling at the speed of light

You guys are talking about travelling through space at the speed of light - of course. But light does also travel through time does it not?? And so we are right now travelling at the same rate as light.... the speed of light (just through time and not space)