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Relativity and the speed of light: What the hell? 
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Post Relativity and the speed of light: What the hell?
What does it mean that the speed of light is constant?

Here’s the idea. If you are sitting in a chair and somebody shines a flashlight by you, the light passes at 186,000 miles per second. This speed is referred to as “C”. The same C as in E=m(C*C), Einstein’s equation. This speed never changes.

Fine. But, why would it ever change?

Well, if you were driving in an imaginary car that could go 1000 miles per second and turned on your headlights, you might expect the light to travel 187,000 miles per second. C plus 1000 miles per second. But it doesn’t work that way.

If you are driving in a car and throw a baseball, it works that way. The speed of the car plus the speed of your throw add together. But that doesn’t work for light.

In the imaginary car, when you turn on the headlights the light will travel away from you at 186,000 miles per second. That sounds like it’s behaving the way you would expect. But somebody sitting in a chair outside the car would see the light pass at C, not C plus 1,000 miles per second. The speed doesn’t change.

How can that be?

First a couple examples, then the explanation that rights everything.

Lets say you are in the chair again, sitting on the surface of the earth. I am in that crazy car again, but I’ve managed to travel 185,999 miles per second. Just a mile per second slower than light. I’m approaching earth and I turn on my headlights and you will see both the beam of light passing by, and then my car, and you will see the difference in speed.

From my perspective in the car I’m approaching earth, I hit the lights and the beam flies away at 186,000 miles per second. That doesn’t seem to jive with what I’ve been saying. That sounds like light is traveling basically twice as fast as it should.

Well you, sitting on a chair on the planet, watch everything go down. You see my car appear, you see the headlights turn on and the beam accelerate ahead of the car. To you, it looks like the beam is just barely outpacing the car. It IS only going 1 mile per second faster than the car. The beam is going 186,000 miles per second, and the car is going 185,999 miles per second. The whole time my car and the beam are in sight my car is hot on the tail of the light beam.

It sounds like you and I are looking at different beams of light. It sounds like the two speeds cannot possibly be the same. Here’s the part that makes it all come together. The speed of light, C, is not just the speed of light. It’s the speed of information. Anything that interacts with anything else is transmitting some kind of information. A magnet’s pull on a piece of metal is information to the atoms of the metal. They “feel” the pull, which is information, and respond. That information can ONLY travel between objects at the speed C or less.

That means everything everywhere is depending on the speed C to interact. That means the tug of the earth’s gravity on your body travels to you at the speed C, the light from the sun, obviously, travels at the speed C, but it also means the chemical interactions of molecules travels at C. And so do the strong and weak nuclear forces. In the case of the nucleus, the force doesn’t have to travel far, but it does have to travel, and it goes at C. No information is transmitted instantaneously.

Keep this in mind.

Now, lets think of one more set of people. One sitting in the chair again, another in a car, both have clocks. The clocks are hollow tubes with mirrors on either end that reflect a beam of light, or a single photon back and forth between them. We keep track of every time the light bounces off a mirror and travels the distance. Lets say the tube is a foot long, so the mirrors are a foot apart. We count the times the light travels between mirrors, and after it has traveled between them and counted up 186,000 miles, then one second has passed.

Both clocks are confirmed to agree with eachother when the guy sitting in the chair has them. He gives one to the guy in the car and they start the experiment. Each guy looks carefully at their clock as they go. One sitting on the chair, the other whizzing by at very close to the speed of light in his car. Both guys report that the light in their clocks is traveling strait up and back down again in the tube. But when the guy in the chair looks up and sees the clock in the car, the light doesn’t look like it’s going strait up and down. It’s traveling in a zig zag.

As the car moves by the light continues going up and down in the clock, but also “horizontal” compared to the man in the chair. The path looks like the series of triangles below, rather than a strait up and down line.

-->

/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\

If you imagine a triangle next to a strait line, and compare the lengths of the strait line to the diagonal of the triangle, this is the difference I’m talking about.

It’s the difference in distance the light has to travel from going to one mirror to the other in the clock by the chair vs the clock in the car.

Light has to travel further to do the same thing in the car than it does by the chair. But not just the light in the clock. All the interactions of everything in the car also has to travel further, and as a result it takes longer to do so. That includes the chemical interactions of your cells, and the neurons in your brain. Every thought in your head takes longer. The consumption of oxygen in your cells takes longer. The combustion of the fuel in the engine takes longer. TIME takes longer. Everything is tied to the speed C. So when it takes longer for the information from one atom to reach another, then the interactions are slowed.

That’s how it looks like the light wizzes past me in my special car at 186,000 miles per second while I’m traveling at 185,999 miles per second. Because time has slowed down. The chemical, nuclear, electromagnetic, and gravitational interactions are all relying on the speed C in my car. The signals spend so long getting from place to place that my time frame slows to a crawl, almost a stop, in fact, until signals appear to travel at the speed C in comparison to my surroundings.

You, sitting on your chair see me whizz by at just a shade under the speed C. I’m traveling nearly as fast and the beam an my car are “neck and neck” so to speak. But that time you are observing me and the beam traveling together, which may seem like “a couple seconds” to you will not even register in the car. Each of my seconds take 2.152778 days for you.

If you could watch me and the beam travel side by side for 2 years only 5.651613 minutes will have passed for me in the car.

That’s how traveling at close to the speed of light alters time. Not just the perception of time, but TIME. If you travel to another galaxy at close to the speed C, the earth will experience ages passing by, while you might only grow 25 years older.

Clear as mud?


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Wed Jul 18, 2012 12:03 pm
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Post Re: Relativity and the speed of light: What the hell?
http://www.wimp.com/trillionframes/

a camera that records the travel of light.

interesting.


_________________
In the absence of God, I found Man.
-Guillermo Del Torro

Have you tried that? Looking for answers?
Or have you been content to be terrified of a thing you know nothing about?

Are you pushing your own short comings on us and safely hating them from a distance?

Is this the virtue of faith? To never change your mind: especially when you should?

Young Earth Creationists take offense at the idea that we have a common heritage with other animals. Why is being the descendant of a mud golem any better?

Confidence being an expectation built on past experience, evidence and extrapolation to the future. Faith being an expectation held in defiance of past experience and evidence.


Tue Jul 31, 2012 2:33 pm
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Post Re: Relativity and the speed of light: What the hell?
johnson1010 wrote:
http://www.wimp.com/trillionframes/

a camera that records the travel of light.

interesting.


I saw that, that's pretty awesome. I didn't even understand what was going on with the time distortion effect.



Tue Jul 31, 2012 5:09 pm
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Post Re: Relativity and the speed of light: What the hell?
I think that was an artifact of the way they were taking the pictures.

If i understood this correctly, and let me know what you got out of it, Dexter, was that the movie was not made of a single burst of photons absorbed as they come back over time, but instead a burst per frame, each frame recorded slightly later in the process to produce a movie.

So, if there were 30 frames, then there were 30 laser emissions and recordings done ever so slightly later per event to accumulate a movie.


_________________
In the absence of God, I found Man.
-Guillermo Del Torro

Have you tried that? Looking for answers?
Or have you been content to be terrified of a thing you know nothing about?

Are you pushing your own short comings on us and safely hating them from a distance?

Is this the virtue of faith? To never change your mind: especially when you should?

Young Earth Creationists take offense at the idea that we have a common heritage with other animals. Why is being the descendant of a mud golem any better?

Confidence being an expectation built on past experience, evidence and extrapolation to the future. Faith being an expectation held in defiance of past experience and evidence.


Thu Aug 02, 2012 11:14 am
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Post Re: Relativity and the speed of light: What the hell?
johnson1010 wrote:
I think that was an artifact of the way they were taking the pictures.

If i understood this correctly, and let me know what you got out of it, Dexter, was that the movie was not made of a single burst of photons absorbed as they come back over time, but instead a burst per frame, each frame recorded slightly later in the process to produce a movie.

So, if there were 30 frames, then there were 30 laser emissions and recordings done ever so slightly later per event to accumulate a movie.


Is that right? That seems less impressive. I thought that because the camera was fast enough, it was in fact tracking a single burst.



Thu Aug 02, 2012 11:29 am
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Post Re: Relativity and the speed of light: What the hell?
That's what i got out of it, Dexter.

But i'm not completely confident about my take on it.

Watch it again sometime and let me know how it tracks with you.


_________________
In the absence of God, I found Man.
-Guillermo Del Torro

Have you tried that? Looking for answers?
Or have you been content to be terrified of a thing you know nothing about?

Are you pushing your own short comings on us and safely hating them from a distance?

Is this the virtue of faith? To never change your mind: especially when you should?

Young Earth Creationists take offense at the idea that we have a common heritage with other animals. Why is being the descendant of a mud golem any better?

Confidence being an expectation built on past experience, evidence and extrapolation to the future. Faith being an expectation held in defiance of past experience and evidence.


Thu Aug 02, 2012 1:15 pm
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Post Re: Relativity and the speed of light: What the hell?
That's what i got from what he says at 5:22.


_________________
In the absence of God, I found Man.
-Guillermo Del Torro

Have you tried that? Looking for answers?
Or have you been content to be terrified of a thing you know nothing about?

Are you pushing your own short comings on us and safely hating them from a distance?

Is this the virtue of faith? To never change your mind: especially when you should?

Young Earth Creationists take offense at the idea that we have a common heritage with other animals. Why is being the descendant of a mud golem any better?

Confidence being an expectation built on past experience, evidence and extrapolation to the future. Faith being an expectation held in defiance of past experience and evidence.


Thu Aug 02, 2012 1:25 pm
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Post Re: Relativity and the speed of light: What the hell?
Here’s a great video from Sixty Symbols which explains what I was talking about in the first post.
http://www.dump.com/timerockets/

Great stuff.

He says something in this video which I’ve heard before but which I think confuses the issue.

Essentially that all the clocks in the traveling ship have to agree (clocks referring to radioactive decay, aging, and actual clocks) so that you can’t tell that you are moving, otherwise it violates relativity.

But this makes it seem as though the law is inflicting itself on reality and changing the way things would otherwise go, like a cosmic cop. But really, relativity is a description of what we observe happening, and what is happening is a property of the way things are already behaving. And that behavior is easy to grasp.

The clocks don’t all agree SO THAT you can’t tell you are moving. You can’t tell you are moving BECAUSE the clocks all agree! And that’s to do with the fact that the light has to travel in that zig-zag in all interactions in the ship. Not only how long it takes a clock to tick, but also how long it takes for you to breathe, and how long it takes for your cells to utilize the oxygen you breathe! Everything goes slower, including you perception of the sequence of events because of that zig-zag.

This zig-zag pattern is the underlying mechanics of relativity! It seems like an easy explanation with a real physical phenomena that can explain a lot of weirdness, but it is not often emphasized the way i think it should be.

Instead of saying relativity means all the clock have to agree, they should explain this zig-zag and say, that's why the clocks agree, and that is the source of relativity!


_________________
In the absence of God, I found Man.
-Guillermo Del Torro

Have you tried that? Looking for answers?
Or have you been content to be terrified of a thing you know nothing about?

Are you pushing your own short comings on us and safely hating them from a distance?

Is this the virtue of faith? To never change your mind: especially when you should?

Young Earth Creationists take offense at the idea that we have a common heritage with other animals. Why is being the descendant of a mud golem any better?

Confidence being an expectation built on past experience, evidence and extrapolation to the future. Faith being an expectation held in defiance of past experience and evidence.


Thu Jan 16, 2014 10:11 am
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