# Speed of light?

• September 2nd, 2007, 09:15 AM
alexp241180
Speed of light?
Hello,

Basic question. If the lights on a spacecraft were turned on and the light from them travelled in the same direction as the ship, the light would travel with the speed of light (c) plus the speed of the ship with regards to an onlooker.

How can that be if the speed of light is finite to c?

Regards

Alex
• September 2nd, 2007, 09:19 AM
GhostofMaxwell
Re: Speed of light?
Quote:

Originally Posted by alexp241180
Hello,

Basic question. If the lights on a spacecraft were turned on and the light from them travelled in the same direction as the ship, the light would travel with the speed of light (c) plus the speed of the ship with regards to an onlooker.

How can that be if the speed of light is finite to c?

Regards

Alex

It will still travel at c to an onlooker, only its wavelength will be shifted.
• September 2nd, 2007, 09:21 AM
alexp241180
But physically in space will it travel at a greater speed
• September 2nd, 2007, 09:32 AM
GhostofMaxwell
Quote:

Originally Posted by alexp241180
But physically in space will it travel at a greater speed

No, It will always travel at c, in regards to the distance of space it traverses in a given time.
• September 2nd, 2007, 10:11 AM
looking4recruits
Use a force.........anything.........

something that can think better than those who don't want to understand you.

No.

I think you are drifting to something else.............good for you./////////

Nevertheless..........

Try identifying why something like me, and screw knowing that, right, would engage in one of your "science parties"........

Me?

You?

I look at you and hope I need to say "less than zero".......based on what you ask not just onself but others to consider...........

It doesn't though "turn back time"...........and you obviously "have no vision for the future".............

Jesus.............
• September 2nd, 2007, 11:26 AM
Harold14370
Quote:

Originally Posted by alexp241180
But physically in space will it travel at a greater speed

You have fallen down the rabbit hole of relativity, where there is no preferred frame of reference. The reference frame you are thinking about where the speed of light is additive is the "lumeniferous aether" which the Michelson-Morley experiment was looking for. It does not seem to exist.
• September 2nd, 2007, 04:50 PM
kojax
Light speed travel limitation is only from a linear perspective. You're only going at C in a straight line because you're bouncing around in a sine wave.

Someone correct me if I'm wrong about this, but it's how I've been given to understand things. At light speed, everything has a wavelength.

So: here's what I'm trying to say.

You're going /\/\/\/\/\/\/\/\/\/\/\/ through space, but the light on your ship is going /\/\/\/\/\/\/\/\/\/\ faster than you are, just in a tighter sinewave pattern. So, you perceive it as going from the front to the back (etc) as it ought to.
• September 2nd, 2007, 05:14 PM
GhostofMaxwell
Yes the wave-length is either expanded or compressed, depending on the radial velocity. Its speed is never increased or decreased though.
• September 13th, 2007, 07:23 PM
SolomonGrundy
Quote:

Originally Posted by GhostofMaxwell
Yes the wave-length is either expanded or compressed, depending on the radial velocity. Its speed is never increased or decreased though.

no realy and what you have to back that up?
kids things are not as you learn they are and i'll say it once agian
Speed of light as you copnsider it to be constant is not because of the mechanism in with the light travels and I say TRAVELS as a joke not as a statement.
Do not eat up all the shit !!! do some experiments and see what realy happens.
Yes there are tools available and there will be more , all you need clear facts examples and then talk .
• September 14th, 2007, 12:15 AM
GhostofMaxwell
Quote:

Originally Posted by SolomonGrundy
Quote:

Originally Posted by GhostofMaxwell
Yes the wave-length is either expanded or compressed, depending on the radial velocity. Its speed is never increased or decreased though.

no realy and what you have to back that up?
kids things are not as you learn they are and i'll say it once agian
Speed of light as you copnsider it to be constant is not because of the mechanism in with the light travels and I say TRAVELS as a joke not as a statement.
Do not eat up all the shit !!! do some experiments and see what realy happens.
Yes there are tools available and there will be more , all you need clear facts examples and then talk .

This is from "doing experiments". Just about Every experiment and measurement I've ever done backs this up.
• September 14th, 2007, 04:21 AM
John Galt
Quote:

Originally Posted by SolomonGrundy
no realy and what you have to back that up?
kids things are not as you learn they are and i'll say it once agian
Speed of light as you consider it to be constant is not because of the mechanism in with the light travels and I say TRAVELS as a joke not as a statement.

So, do share with us Solomon, your remarkable insights into the true nature of light. Stop spouting your adolescent diatribes (with crappy spelling and incoherent grammar) and give us something of substance instead. Or is that too much of a challenge for you?
Alternatively you might want to consider having the strength of your medication increased.
• September 15th, 2007, 07:50 AM
kojax
Quote:

Originally Posted by GhostofMaxwell
Yes the wave-length is either expanded or compressed, depending on the radial velocity. Its speed is never increased or decreased though.

It doesn't increase in a linear direction, no. It's sort of like the difference between how far something is on a map if you have to drive your car there, or how far away it is as the crow flies.

If you changed your perspective and looked at the sine wave path of the photon as though it were a straight line, you'd find that the photon is actually going faster than C.

If you were on the ship, that curvy path would seem like a straight line to you, and you'd see the light that was emitted moving away from you at a speed that seems like C.

(I know this is going to need a lot of clarification. It's hard for me to exactly explain it)
• September 15th, 2007, 08:14 AM
GhostofMaxwell
What are you talking about? What part of radial velocity do you not understand?

Doppler shift is entirely about linear velocity towards and away from the observer - The observer is situated at one point in space, therefore no progression along co-ordinates in other planes effects wavelength.
• September 15th, 2007, 10:37 PM
kojax
I imagine the radial velocity comes into play if the observer is moving in a sine wave pattern as well.

The observer (on a space ship traveling at C) is seeing a straight line where we see a squiggly line. They would perceive the radial velocity as though it were straight line velocity.

Mind you, I mean they'd see a certain portion of it as straight line velocity. The light emitted from the back of the ship toward the front has a shorter wavelength than the ship itself has, so its movement pattern only partly matches their own.

You cannot observe another object's velocity/direction independent of your own velocity/direction. So, if you're moving in a sine wave pattern, and the object you look at is moving in a somewhat similar sine wave pattern, well...... every change in location it makes, you, the observer, make a corresponding change.
• September 15th, 2007, 11:57 PM
Janus
Quote:

Originally Posted by kojax
Light speed travel limitation is only from a linear perspective. You're only going at C in a straight line because you're bouncing around in a sine wave.

Someone correct me if I'm wrong about this, but it's how I've been given to understand things. At light speed, everything has a wavelength.

So: here's what I'm trying to say.

You're going /\/\/\/\/\/\/\/\/\/\/\/ through space, but the light on your ship is going /\/\/\/\/\/\/\/\/\/\ faster than you are, just in a tighter sinewave pattern. So, you perceive it as going from the front to the back (etc) as it ought to.

It seems that you are suffering from a misconception that I've run across before; That the wavelength of light is due to photons traveling in a sinewave pattern. This is not the case. Photons travel in a straight line and a photon's wave length has nothing to do with the path the photon travels.
• September 17th, 2007, 12:07 AM
kojax
So how does light bend around corners? Well, obstructions, not corners exactly.

I'll admit I'm foggy on the specifics of this concept though. If you could clarify it for me I'd be very interested. Is the wavelength physical motion in space, or just the oscillation between electrical and magnetic field, or both?