Those darn little corruptors.
The stackexchange link should be http://physics.stackexchange.com/questions/143576/is-it-a-postulate-or-a-well-proven-fact-that-speed-of-light-remains-constant
I speak not of the true speed of light as you say, but clearly stated the “Relative” speed, relative to the tube. The introduction of “Relative” instantly excludes any discussion or claim of “absolute” or “real”.
That stackexchange post answer being noted, by the way, is of my own doing.
Doesn’t really matter. No matter who observes it, the speed of light is constant in all inertial frames of reference. As people have noted above, the experiments confirm this fact.
This is a very common misconception for people who are studying relativity. Things break down by adding velocities in a Galilean fashion (as you are doing here) instead of using the Lorentz transformation. Our intuition breaks down hard in light of this.
As it happens, Einstein himself didn’t like the term “relativity” and really thought it should have been called an invariance theory, as the speed of light is invariant, i.e. constant no matter the observer. All your thinking should start with that single fact that no matter how it is measured, the speed of light is constant and is not relative to any inertial frame of reference.
PEOPLE CONSTANTLY GET IT MIXED UP.
But despite the above obvious facts, most people still don’t get what this means.
The whole meaning of these 3 statements combined, is greater than the sum of the parts.
Most folk just don’t have what it takes to see beyond relativity, thus they are confined to having an incomplete understanding of special relativity, and do so since they are incapable of seeing the absolute of which Special Relativity resides within.
They truly think that there is no absolute !
Thus they says that reality absolutely does not exist.
What is this “absolute” that special relativity resides within?
The speed of light relative to the tube is still 3e8 m/s, just like the speed of light relative to anything else.
This.
If you are claiming that the speed of light relative to the tube is not 3e8 m/s, that is at odds with relativity.
What is this “absolute” that special relativity resides within, YOU SAY.
Well, like I have stated before, if you analyze the idea of absolute motion ongoing within an absolute 4 dimensional Space-Time environment, you encounter the bizarre structure that is needed to make motion, as we know of it, possible.
In turn, from this absolute point of view, one knows exactly why clocks slow down, why lengths contract, and visually one can perceive the physical structure that lies behind the Lorentz Transformation equations.
Meaning, by seeing the absolute foundation, ones mind literally wraps completely around Special Relativity, and thus one can see it as a singularity rather than see it as something that is branched together via mere equations.
Treating a reference frame as 4-D spacetime allows you to geometrically arrive at transformations between that frame and other frames. However, that doesn’t mean that there exists some absolute 4-D frame independent of all observers.
NUFOIB, are there any measurements that could be made that would tell you which frame of reference is the absolute one?
If you’re only seeing things in one reference frame, then you’re not seeing all of relativity, just one slice of it. You’re missing out.
Yes, watching the video, that is his flaw. He is projecting an absolute 4-D coordinate system, and then proposing we all shift differently within that system depending upon our velocity.
Relativity says that we can all see an axis system like that, but there is no absolute position from which to define that absolute frame.
NUFOIB, standard coordinate system math talks about defining your arbitrary axis system, beginning using a simple 2-axis X and Y system. Then a second arbitrary axis system can be defined at some other point X’ and Y’. Mathematically, you can relate the two using geometry and trigonometry, just like you do with your space-time system. But the trick to remember is that both the X-Y and X’-Y’ systems are arbitrary. You decide where you want them and how to align them to make the math easy or to aid visualization. But they are abstract mental constructs projected onto the situation. Neither has an absolute, preferred “real” status.
Sure, you align one with the horizon, and one with the slope of the floor, for example, so you can talk about the normal force and the friction force along the slope and then relate that to gravity. But those are still fictions created to make the math easier to see. There’s nothing real to them, and you can choose the X’-Y’ system as your preferential system if you choose.
Relativity is the same thing - the 4-D axis system is a projection from a particular reference frame, and a different reference frame will have a different projection.
There’s no “time” axis. There is spacetime, and any axis can be time compared to the other three space axes for that reference frame.
Here is where you are getting tripped up, though: clocks do not slow down, lengths do not contract, mass does not increase, these effects are observations across reference frames.
If you, for example, got a seat on Voyager 1, the onboard clock would tick at a constant rate, but if you were to report the time back to CapCom (right now, today), it would not match up with the clock in Houston, which has also been ticking at the same constant rate. If you measured the RTG boom and compared that to an impossibly precise measurement made from Earth, your local observation would not match the observation made from the other reference frame. The differences would be pretty small, but they would be there. Your local objects are all the same as they were, but they look different to observers in other reference frames.
You see, “relative” is actually the exact opposite of “absolute”, that is why it is named that.
From the perspective of someone outside the tube, where the tube is moving at 260,000 km/s relative to them, would they not observe the light to be traveling 40,000 km/s faster than the tube? I believe this is what he is trying to say.