The Theory of RELATIVITY

[arian]

[JohnPaul]

.

This is getting tedious. Again, I ask if you are joking? I completely agree with everything you wrote in your description of your experiment, EXCEPT you completely ignored any mention of the whole point of this discussion, the measurement of the speed of the water as it moves between the hose nozzle and the target. Its back-and-forth motion is irrelevant. To measure this speed, we must know the distance between the nozzle and the target, and also a way of comparing the exact times at which the water leaves the nozzle and the time at which it strikes the target. That was the whole point of Roemer's observation. How did you miss it?

I think that you missed it too.

The experiment has nothing to do with the speed, time or distance it left the hose (Jupiter) till it got to the garage door (Earth).
The experiment is better described as a constant pulsating beam of water shot at a moving car (Earth).
When the car is going toward the hose it will hit rapidly ta-ta-ta, but when the car is going away it will hit slower pahdah-pahdah-pahdah. Then if you know the distance the car traveled during the pulse of water, then the difference in time of the two pulses hitting the car and the distance the car traveled will allow you to calculate the speed of the water.

You are right olavisjo, and I believe JohnPaul is right too, in my case anyways. I did not consider what would happen if my gun was either moving closer or farther AS it was shooting out water, and your pulsating water gun clearly shows what would happen. From space, as the source (which is my water gun) moved away as it was shooting, the intervals of each pulse would be farther apart, but what about light which is claimed is constant no matter how its being emitted, coming or going away from the target?

I do understand that light has to be a constant which I thought as INSTANT, but if the Jupiter's moon Io experiment was honest, then light does have a speed, and for this to work, it HAS to be constant.

But then I have to put it in such a perspective where I could visualize this. I understand what JohnPaul is saying, and according to that observation of Io, light would seem to have speed, actually in that sense it must have speed and a constant one at that. But I still have to figure it out in my own simple way to be able to see it in my own mind.

OK, if the speed limit of light in this universe is 186,282 m/p/s MAX

My biggest problem now is to understand this speed limit of light. OK, so I visualize a ship with headlights traveling let's say 170,000 m/p/s, and then turns on his headlights, so with a speed limit on light, that light coming out of the headlight, within this universe can only be 186,282-170,000=16,282 m/p/s, which keeps the light within the universal speed limit of 186,282 m/p/s.

But from my ships perspective, my frame of reference I have a light front of me and originating from me, .. a beam of light that is only traveling at a speed of 16,282 m/p/s

what is wrong with this picture?

I thought that from any source, from any perspective LIGHT is a CONSTANT?

Another word, when I asked about a sun on the outer skirts of the fabric of our universe traveling near or faster than the speed of light, what speed did the light emanating from the front of that sun travel?
I was told that 'light travels at 186,282 m/p/s no matter which direction the source (in this case the sun) was traveling'. And since the source is a sun, it is emanating light in every direction at a constant C.
How is this explained?

Thanks for anyones input.

I will try a couple of answers. "Why" is a very deep question. Science tries to explain "how" things work, but often cannot explain the deeper question of "why." The speed of light at 186,282 mps is one of the many constants of nature which we find in the universe around us. Call it a whim of God if you like. Some people talk about the "permeability of space" limiting the speed of light, but that only pushes the question back a step. What and why is permeability?

The question about the relativistic effect of the earth's speed in its orbit on observations of light from Jupiter's moon is that the speed of the earth in its orbit at only 19 mps is so very small compared to the speed of light that no relativistic effects are noticeable.

As for your question about the spaceship moving at 170,000 mps and emitting a beam of light ahead of it, the answer would be different depending on whether you are observing it from earth or from the moving ship. Remember that the speed of light is ALWAYS measured as 186,282 mps for ALL observers, no matter what the speed of the observer may be. By ordinary everyday experience on earth, the speed of the beam of light limited to 186,282 mps should seem to the ship's crew to be travelling at only 16,282 mps relative to the ship, but you are forgetting about the relativistic time dilation for the ship at that speed, which means that a second to them is longer (as measured from earth), so the beam of light seems to them to travel farther in their longer version of a second. So, as measured by the ship's crew using ship's time, the beam of light is travelling away from them at 186,282 mps while they seem to be standing still. I know this is confusing at first exposure to it, and is difficult to keep straight in your mind while trying to visualize it. Incidentally, both Relativity and Quantum physics contain ideas which are actually impossible for the human mind to visualize and can only be expressed mathematically.

Welcome to the deep end of the pool. I welcome corrections to what I have written above.

[A Troubled Man]

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P.S. Perhaps I should apologize for berating you too harshly for your misunderstanding of Roemer's method of measuring the speed of light from observations of Jupiter's moon Io. It seems that a French reporter in 1676 also misunderstood it and totally garbled his report of it in Paris. So you are not the first to misunderstand it, and I apologize.

But, the point is that water does not behave the same way as light. For example, with light, the car will be hit exactly the same (ta-ta-ta) whether it is at rest or moving fast, the light will not hit it slower (pahdah-pahdah-pahdah) as would the water. Huge difference.

A French reporter, JohnPaul and now A Troubled Man all misunderstood it.

Read it again, it is not rocket science (or is it?)...

http://en.wikipedia.org/wiki/Ole_R%C3%B ... d_of_light

Sorry, what is it exactly we are misunderstanding?

[JohnPaul]

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P.S. Perhaps I should apologize for berating you too harshly for your misunderstanding of Roemer's method of measuring the speed of light from observations of Jupiter's moon Io. It seems that a French reporter in 1676 also misunderstood it and totally garbled his report of it in Paris. So you are not the first to misunderstand it, and I apologize.

But, the point is that water does not behave the same way as light. For example, with light, the car will be hit exactly the same (ta-ta-ta) whether it is at rest or moving fast, the light will not hit it slower (pahdah-pahdah-pahdah) as would the water. Huge difference.

A French reporter, JohnPaul and now A Troubled Man all misunderstood it.

Read it again, it is not rocket science (or is it?)...

http://en.wikipedia.org/wiki/Ole_R%C3%B ... d_of_light

Sorry, what is it exactly we are misunderstanding?

I think it had something to do with washing cars on Jupiter.

[arian]

I will try a couple of answers. "Why" is a very deep question. Science tries to explain "how" things work, but often cannot explain the deeper question of "why." The speed of light at 186,282 mps is one of the many constants of nature which we find in the universe around us. Call it a whim of God if you like. Some people talk about the "permeability of space" limiting the speed of light, but that only pushes the question back a step. What and why is permeability?

Hey thanks again JohnPaul.

Yes, I can see that permeability would seem to explain a speed limit on light, I kind of visualize this as friction on a book sliding on a desk, or actually water seeping through a vey fine strainer. I imagine pouring a gallon of water in a big bowl fine gradient strainer where the water would permeate through the strainer (matter) at a constant. But it's not a strainer, because they say that the slowing process of light in matter is thought to result not from actual slowing of particles of light, but rather from their absorption and re-emission from charged particles in matter.

But what is the substance that light permeate through absorption and re-emission in space to keep it at this speed limit? If it's not some substance in space, then what, some magnetic flux?
Or is it gravity of space? Is the entire space in the universe made up of some sort of constant gravity acting like a strainer that limits light to this constant? Actually I could see that, and it would explain a lot of things.

Hey, .. that would also explain why the weight of a spaceship flying through space would increase exponentially at faster and faster speeds, .. because the faster the ship went, the more space/gravity it would accumulate on/in the ship! So the mass of the ship would remain the same, ONLY the weight would increase, with all them quantum gravity that is accumulating in the ship.

By Einstein, I think I'm getting it, .. or am I just creating my own explanations again?

The question about the relativistic effect of the earth's speed in its orbit on observations of light from Jupiter's moon is that the speed of the earth in its orbit at only 19 mps is so very small compared to the speed of light that no relativistic effects are noticeable.

Well yes you are right, that would be very minute.

As for your question about the spaceship moving at 170,000 mps and emitting a beam of light ahead of it, the answer would be different depending on whether you are observing it from earth or from the moving ship. Remember that the speed of light is ALWAYS measured as 186,282 mps for ALL observers, no matter what the speed of the observer may be. By ordinary everyday experience on earth, the speed of the beam of light limited to 186,282 mps should seem to the ship's crew to be travelling at only 16,282 mps relative to the ship, but you are forgetting about the relativistic time dilation for the ship at that speed, which means that a second to them is longer (as measured from earth), so the beam of light seems to them to travel farther in their longer version of a second. So, as measured by the ship's crew using ship's time, the beam of light is travelling away from them at 186,282 mps while they seem to be standing still.

Yes JohnPaul time slowing down would make perfect sense as you explained above. I have no problem in understanding that.
Only for some reason, .. for now, with all the experiments I have done in my head regarding time dilation, I just cannot see TIME slowing down as we travel faster. and here is one example why; (there is more)

Look;

* take two ships facing opposite directions, and make the Space-station as our starting point, as our inertial frame of reference.

* Now let both ships accelerate to 0.4 C in a straight line going the opposite direction, OK?

* After about a light month, they both stop and return to the space station.

Now what is the age, or time difference between each ship? There is none, right? Why? It is because of the symmetry of acceleration, both ships would have aged the same.

OK, now lets do this again and add two more ships, but this time let's add a shuttle facing backwards onto one of the LEFT moving ships traveling right towards the Space Station, and we have another ship coming in from the RIGHT of the space station, ..all traveling at 0.4 C.

Now once they reach the Space Station, the LEFT ship carrying the shuttle looses the shuttle and continues to travel the same direction to the right at 0.4 C past the space station,
and the RIGHT ship continues in the same direction passing the space station to the left. (they pass each other going opposite directions), BUT back at the same inertial frame right at the space station the shuttle launched from the LEFT ship and started heading left at 0.8 C.

See the speed paradox, the time paradox follows:

* So in the same inertial frame we have the RIGHT ship that just passed the space station traveling left at 0.4 C, side by side with the shuttle (that launched off of the LEFT ship) traveling at 0.8 C the same direction side by side for the duration of a light month.

* In the opposite direction we also have two ships traveling at 0.4 C, one of them is the ship the shuttle launched off from, .. and at exactly one light month they all turn around and they all arrive at the space station.

In the two shared inertial frames that arrived at the space station, the shuttle aged less then the other ships.

I know this is confusing at first exposure to it, and is difficult to keep straight in your mind while trying to visualize it. Incidentally, both Relativity and Quantum physics contain ideas which are actually impossible for the human mind to visualize and can only be expressed mathematically.

Thank you again JohnPaul. Please don't take this as arrogance on my part, but I understand all the concepts of quantum physics I have read, heard and seen so far, but the mathematical part I couldn't even start without taking grade school Algebra, Geometry, (I know Trigonometry pretty good) but would definitely need a few years of physics. So far there has been no philosophical, or scientific concept that I could not understand, it is the rules and the laws that I need to brush up on, as evidenced in this OP. This is probably why I sound so 'way out there', or as if I didn't know what I was talking about, because I lack the basics to explain to someone what I already know. But I am working the best I can learning those basics.

Welcome to the deep end of the pool. I welcome corrections to what I have written above.

Yes it is deep, .. but I like deep. Thanks for giving me a chance.

[olavisjo]

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But, the point is that water does not behave the same way as light. For example, with light, the car will be hit exactly the same (ta-ta-ta) whether it is at rest or moving fast, the light will not hit it slower (pahdah-pahdah-pahdah) as would the water. Huge difference.

A French reporter, JohnPaul and now A Troubled Man all misunderstood it.

Read it again, it is not rocket science (or is it?)...

http://en.wikipedia.org/wiki/Ole_R%C3%B ... d_of_light

Sorry, what is it exactly we are misunderstanding?

If you have a constantly pulsating source (be it water, light or sound) that source will be compressed or elongated if the distance to or from that source increases or decreases. Think of a motorcycle approaching you at a constant speed, you will hear the pitch of the engine drop when it passes you even though the speed of the motorcycle did not change. This is called the "Doppler effect". If you can calculate the amount of the drop and you know the speed of sound you would be able to know how fast the motorcycle was going, or vice versa.
This Doppler effect was what Ole Rømer used to calculate the speed of light (it would be over 150 years latter that Doppler named this effect).
Rømer noticed that the period of Jupiter's moon Io should be constant at about 42.5 hours, if light was transmitted instantly. But it was not constant, and he noticed that when the Earth was moving toward Jupiter that the period became about 15 seconds quicker, and when the Earth was moving away from Jupiter the period was 15 seconds longer. (due to the Doppler effect)
The Earth orbits the Sun at a speed of about 107,300 km/hr times 42.5 hrs gives us a distance of 4,560,250 km. Rømer figured that the reason the period of Io was shorter was because the light did not have to travel as far to get to the Earth, it got there sooner because the Earth had moved closer to Jupiter. So the speed of light would then be 4,560,250 km divided by 15 sec or about 300,000 km/sec.

I hope you can understand that, because I just don't know how I can make it any simpler. But there is no "Huge difference" between water, waves, sound or light when we are talking about the Doppler effect.

I think that JohnPaul could have explained this to you if his car had not been dirty at the time.

[A Troubled Man]

This Doppler effect was what Ole Rømer used to calculate the speed of light

"Rømer never did compute the speed of light, maybe because he felt that the distance between the Earth and the Sun was not known too well."

http://www.rundetaarn.dk/engelsk/observ ... /light.htm

[JohnPaul]

This Doppler effect was what Ole Rømer used to calculate the speed of light

"Rømer never did compute the speed of light, maybe because he felt that the distance between the Earth and the Sun was not known too well."

http://www.rundetaarn.dk/engelsk/observ ... /light.htm

OK, but other people did compute it using the data which Roemer had compiled. Roemer was not even trying to measure the speed of light. That was an accidental result of his work. Roemer was onlly looking for something in the sky for ocean navigators to us as a "clock" to give them accurate time which they needed to navigate and compute their position on the open ocean. Only pendulum clocks were accurate at that time, and these could not be used on ships because the motion of the ocean waves disturbed the accurate swings of the pendulums. Roemer failed to find a useful navigation "clock" in the sky, but he did find more than he was looking for.

[JohnPaul]

[Replying to post 174 by arian]
Arian, your sample problem involving multiple spaceships moving at different speeds and in different directions is too complicated for my feeble brain to tackle at the moment. I will leave it to some of the geniuses here in the forum. Besides, it involves acceleration, speeding up and slowing down, turning around, etc. That completely screws up the relatively simple math of motion at constant speeds, and requires more math than I have. It would involve General Relativity math, not just Special Relativity, and even Einstein needed help with that.

Besides the complicated math to calculate the relativistic effects, your example involves some practical engineering problems. Accelerating at a rate tolerable to humans, a spaceship would have to fire its rockets continuously for several months to reach a speed of .8 C, and the same again for slowing down. By that time, the ship would not only be far beyond the space station, it would be completely out of the Solar System and on its way to the stars. Also, chemical rockets can carry enough fuel to fire their rockets for only a few minutes, certainly not for several months. Even if we developed fusion drives, there would still be the problem of carrying reaction mass. I am afraid it will be some time before your hypothetical problem becomes a real problem.

[A Troubled Man]

Yes JohnPaul time slowing down would make perfect sense as you explained above. I have no problem in understanding that.
Only for some reason, .. for now, with all the experiments I have done in my head regarding time dilation, I just cannot see TIME slowing down as we travel faster. and here is one example why; (there is more)

Time does not slow down for us as we travel faster, our clocks tick as normally as if we were at rest. It is the clocks that are at rest or moving at different velocities from us that are observed to tick slower.

Look;

* take two ships facing opposite directions, and make the Space-station as our starting point, as our inertial frame of reference.

* Now let both ships accelerate to 0.4 C in a straight line going the opposite direction, OK?

* After about a light month, they both stop and return to the space station.

Now what is the age, or time difference between each ship? There is none, right? Why? It is because of the symmetry of acceleration, both ships would have aged the same.

That is correct.

OK, now lets do this again and add two more ships, but this time let's add a shuttle facing backwards onto one of the LEFT moving ships traveling right towards the Space Station, and we have another ship coming in from the RIGHT of the space station, ..all traveling at 0.4 C.

Now once they reach the Space Station, the LEFT ship carrying the shuttle looses the shuttle and continues to travel the same direction to the right at 0.4 C past the space station,
and the RIGHT ship continues in the same direction passing the space station to the left. (they pass each other going opposite directions), BUT back at the same inertial frame right at the space station the shuttle launched from the LEFT ship and started heading left at 0.8 C.

See the speed paradox

I see no "speed paradox" at all, what exactly are you referring?

the time paradox follows:

* So in the same inertial frame we have the RIGHT ship that just passed the space station traveling left at 0.4 C, side by side with the shuttle (that launched off of the LEFT ship) traveling at 0.8 C the same direction side by side for the duration of a light month.

* In the opposite direction we also have two ships traveling at 0.4 C, one of them is the ship the shuttle launched off from, .. and at exactly one light month they all turn around and they all arrive at the space station.

In the two shared inertial frames that arrived at the space station, the shuttle aged less then the other ships.

Not necessarily, the shuttle was traveling faster than the other ships, hence the time dilation calculations must be derived separately based on the changes in velocity. Doubling the speed does not mean we double the dilation.

Thank you again JohnPaul. Please don't take this as arrogance on my part, but I understand all the concepts of quantum physics I have read, heard and seen so far, but the mathematical part I couldn't even start without taking grade school Algebra, Geometry, (I know Trigonometry pretty good) but would definitely need a few years of physics. So far there has been no philosophical, or scientific concept that I could not understand

And yet, to actually gain full understanding of those physics concepts, one must indeed understand the math. It simply doesn't work with mere layman's terms.

[JohnPaul]

Yes JohnPaul time slowing down would make perfect sense as you explained above. I have no problem in understanding that.
Only for some reason, .. for now, with all the experiments I have done in my head regarding time dilation, I just cannot see TIME slowing down as we travel faster. and here is one example why; (there is more)

Time does not slow down for us as we travel faster, our clocks tick as normally as if we were at rest. It is the clocks that are at rest or moving at different velocities from us that are observed to tick slower.

Look;

* take two ships facing opposite directions, and make the Space-station as our starting point, as our inertial frame of reference.

* Now let both ships accelerate to 0.4 C in a straight line going the opposite direction, OK?

* After about a light month, they both stop and return to the space station.

Now what is the age, or time difference between each ship? There is none, right? Why? It is because of the symmetry of acceleration, both ships would have aged the same.

That is correct.

OK, now lets do this again and add two more ships, but this time let's add a shuttle facing backwards onto one of the LEFT moving ships traveling right towards the Space Station, and we have another ship coming in from the RIGHT of the space station, ..all traveling at 0.4 C.

Now once they reach the Space Station, the LEFT ship carrying the shuttle looses the shuttle and continues to travel the same direction to the right at 0.4 C past the space station,
and the RIGHT ship continues in the same direction passing the space station to the left. (they pass each other going opposite directions), BUT back at the same inertial frame right at the space station the shuttle launched from the LEFT ship and started heading left at 0.8 C.

See the speed paradox

I see no "speed paradox" at all, what exactly are you referring?

the time paradox follows:

* So in the same inertial frame we have the RIGHT ship that just passed the space station traveling left at 0.4 C, side by side with the shuttle (that launched off of the LEFT ship) traveling at 0.8 C the same direction side by side for the duration of a light month.

* In the opposite direction we also have two ships traveling at 0.4 C, one of them is the ship the shuttle launched off from, .. and at exactly one light month they all turn around and they all arrive at the space station.

In the two shared inertial frames that arrived at the space station, the shuttle aged less then the other ships.

Not necessarily, the shuttle was traveling faster than the other ships, hence the time dilation calculations must be derived separately based on the changes in velocity. Doubling the speed does not mean we double the dilation.

Thank you again JohnPaul. Please don't take this as arrogance on my part, but I understand all the concepts of quantum physics I have read, heard and seen so far, but the mathematical part I couldn't even start without taking grade school Algebra, Geometry, (I know Trigonometry pretty good) but would definitely need a few years of physics. So far there has been no philosophical, or scientific concept that I could not understand

And yet, to actually gain full understanding of those physics concepts, one must indeed understand the math. It simply doesn't work with mere layman's terms.

Hmmm. Problems like these have always confused me, math or no math. For example, the two ships leaving the space station in opposite directions at speed of .4 C and then returning would be symmetrical in relation to the space station, but they have been moving at .8 C in relation to each other, so the time difference between the two ships would be quite different than that between each ship and the space station? Also, most of the time would be spent in accelerating and decellerating, which I understand is quite different than motion at a constant speed.