Originally posted by AThousandYoungThe VCR example gives me a little insight into how you are viewing it; however, I
Kelly - listen to me - nothing "pops out" of a timeline!
Here, envision it like this.
You have two VCRs playing two movies. You can put one VCR on fast forward and then press play later and the "story will have aged" - that is, been playing on the screen for more of the movie in the same amount of time.
That's what moving fast does, but in r ...[text shortened]... nt, but the tape will take longer to finish than in the case of a VCR tape on fast forward.
don't see it as much different than what you were saying before.
Kelly
Originally posted by KellyJayWell, does a VCR movie in slow motion ever jump out of this timeline? If not, how can fewer images and dialogue take place in the same amount of time as a movie at regular speed?
The VCR example gives me a little insight into how you are viewing it; however, I
don't see it as much different than what you were saying before.
Kelly
What physicists call "changing time" through relativistically fast motion is equivalent to "changing how fast the movie plays".
Originally posted by AThousandYoungYes, the VCR movie does or can go in slow motion, or faster for that matter, what
Well, does a VCR movie in slow motion ever jump out of this timeline? If not, how can fewer images and dialogue take place in the same amount of time as a movie at regular speed?
What physicists call "changing time" through relativistically fast motion is equivalent to "changing how fast the movie plays".
does not happen is only one person in the VCR movie go faster or slower in the
movie while the rest of the movie remain moving at the same speed.
It all moves together or it rips apart.
Kelly
Originally posted by KazetNagorraAbout .86c, or 258,000 Km/sec or about 162,000 miles per second.
To get a time dilation of 2:1 you need a gamma factor of 2, which means you need a velocity of sqrt(3)/2 times the speed of light.
At that velocity, if you have that velocity all the way, you go to Alpha Centauri, your clocks tell you it took 2 years, Earth clocks still say it took you more than 4 years to get there, so you stay for a year, go back at the same velocity, you age 5 years but 9 years or so goes by on Earth.
Originally posted by KellyJayI suspect you are still not getting it. There is no ripping, only distortion. We can communicate with GPS satellites at all times. Lets suppose Person A is communicating with Person B who was experiencing a time dilation with a factor of 2. We are both counting off seconds, this is what they would experience.
Yes, the VCR movie does or can go in slow motion, or faster for that matter, what
does not happen is only one person in the VCR movie go faster or slower in the
movie while the rest of the movie remain moving at the same speed.
It all moves together or it rips apart.
Kelly
Person A Person B
1 1
2
3 2
4
5 3
6
7 4
8
9 5
10
(not sure how to do the layout etc in these forum posts)
Person A would think person B is in slow motion. Person B would think person A was super fast.
However, even if they communicated using light signals and nanosecond computer counters, there would never be a disconnect in which one pops out of time and back.
You would instead see:
Person A Person B
1.000000000 1.000000000
1.000000001
1.000000002 1.000000001
etc
Originally posted by sonhouseThere is a subtlety here though in that you have to correct for the fact that you have to very rapidly accelerate while stopping at and leaving Alpha Centauri, and this influences time dilation significantly.
About .86c, or 258,000 Km/sec or about 162,000 miles per second.
At that velocity, if you have that velocity all the way, you go to Alpha Centauri, your clocks tell you it took 2 years, Earth clocks still say it took you more than 4 years to get there, so you stay for a year, go back at the same velocity, you age 5 years but 9 years or so goes by on Earth.
Originally posted by twhiteheadI again acknowledge what you’re saying; I'm still asking the same thing why do you
I suspect you are still not getting it. There is no ripping, only distortion. We can communicate with GPS satellites at all times. Lets suppose Person A is communicating with Person B who was experiencing a time dilation with a factor of 2. We are both counting off seconds, this is what they would experience.
Person A Person B
1 1
2
3 ...[text shortened]...
1.000000000 1.000000000
1.000000001
1.000000002 1.000000001
etc
think it time and not some physical dilation with the same factors? The moments
remain the same for both, yet one is under going dilation? If time does not at
all change then those things going through a dilation are apart from time, yet
the results of those changes distort our abilities to stay in sync.
If you are not in sync with me in time in my house, say you were here in my living
room two years ago I'd not be able to see you while I'm in the house now. If you
were in my house yesterday while I was not, I'd not be able to see you now, if
you were in my house an hour before I got here and left, I'd not be able to see you
now, if you were here... Get my point? If we are not sharing now together you
are either in my past or future, neither of which I can interact with, I cannot see
you even if you were seconds out of sync with me.
Kelly
Originally posted by KellyJaywhy do you think it time and not some physical dilation with the same factors?
I again acknowledge what you’re saying; I'm still asking the same thing why do you
think it time and not some physical dilation with the same factors? The moments
remain the same for both, yet one is under going dilation? If time does not at
all change then those things going through a dilation are apart from time, yet
the results of those changes disto I can interact with, I cannot see
you even if you were seconds out of sync with me.
Kelly
Does it matter? It's simply about definitions. You don't like physicists calling their variable "time"...ok. Well, that's what they call it in physics. You don't have to like it but that's the convention.
Imagine trying to force the electrical engineering community to switch to metric and to refer to current as the movement of electrons instead of positive charge. It might be a good idea to make those changes but it's just not going to happen, and it doesn't ned to happen. The engineering works either way.
Originally posted by KazetNagorraA lot of subtilities here for sure! For instance, if you go 0.866 c, you are in fact doing 158,000 miles per second so is the time which is supposed to be viewed onboard as twice as fast as Earth clock exactly that? If you are going 158,000 MPS, then to go 4.3Ly, (the distance to Alpha Centauri), about 2.5E13 miles would take about 157 million seconds non-relativistically speaking or almost exactly 5 years, Earth time.
There is a subtlety here though in that you have to correct for the fact that you have to very rapidly accelerate while stopping at and leaving Alpha Centauri, and this influences time dilation significantly.
So does that mean now if time is stretched times 2 here, it takes exactly 2.5 years to get there?
Of course you are right about the average velocity, I think you need to average 0.866c to get 2 times time dilation. That would include the accel and decel phase. At one G, that would take just about 300 days to accomplish and decel the same so the average there would be .433c during the accel and decel phase. There would not be much time dialation total for that period of travel, some but nowhere near 2 times as in the coasting velocity of 0.866c. The total of 600 days of 0.433 average would cover about 3/4 of a light year or 3/8 light year on each leg would add enough time so the 2.5 year voyage would now stretch to 3 and a third years, so total trip time looks like it would be 6 2/3 years, still a savings of nearly 2 years of ship time V Earth time.
Originally posted by sonhouseWell, when you accelerate or decelerate with respect to some observer, you jump on another frame, so you cannot apply the time dilation formula anymore.
A lot of subtilities here for sure! For instance, if you go 0.866 c, you are in fact doing 158,000 miles per second so is the time which is supposed to be viewed onboard as twice as fast as Earth clock exactly that? If you are going 158,000 MPS, then to go 4.3Ly, (the distance to Alpha Centauri), about 2.5E13 miles would take about 157 million seconds non-r ...[text shortened]... looks like it would be 6 2/3 years, still a savings of nearly 2 years of ship time V Earth time.
KellyJay, I think you are merely quibbling about mathematics and definitions here. Even if we were to change the mathematics to reflect your perspective (assuming it can be done -- which I think it probably can), it would not change the physics one bit.
It would seem to me that a mathematical framework to reflect what you are saying would be far more algebraically involved than the current model. Secondly, the current definition of time, which includes time dilation at relativistic velocities, makes the physics conceptually a lot simpler (i.e. we can use the principle of relativity in inertial reference frames). The way things have been defined (the concept of time) is for convenience.
This does not, of course, imply that this is all fine and dandy in mathematics, but inconsequential to the real world. On the contrary, these concepts describe the real world quite accurately. This implies that by our definition of time, its passage really is dependent on relative motion.
Again, this is a purely mathematical and semantic argument. The physics remains the same. Your incredulity to relativity seems misplaced, because your framework does not change the physics, albeit the mathematics would be more involved. Your protests should be directed at the definitions, not really the physics.
Originally posted by KellyJayNo, I am not entirely sure what you point is.
Get my point?
In my scenario, we do stay in contact with GPS satellites more or less at all times.
As for your question:
I again acknowledge what you’re saying; I'm still asking the same thing why do you think it time and not some physical dilation with the same factors?
Its the most simple explanation. It works. If we use the equations of relativity (in which time is relative) we not only find that it matches reality to an extraordinary degree, but has been able to correctly predict phenomena long before they were actually observed.
I fully realize that there may be some other explanation that relies on a universal time concept, but so far I don't have one. I also don't have any reason to think that such an explanation exists - so it is merely an interesting possibility that seems elegant because we find it more intuitive.
However, considering the experimental evidence so far, I am fairly sure that even if time is not relative and the effects are due to something else, we would still, to all intents and purposes, experience time dilation should we be put in the appropriate situation. ie if we were on a space ship going at near light speed, we would experience time dilation whether or not it was due to actual time slowing down or some other unknown effect.
In the same way GPS satellites must have their clocks adjusted in order to take into account these effects regardless of the actual cause.
Let's say that we redefine 'twin' for a while. The ordinary one is that two persons are born at the same time of the same mother. But let's, as an experiment, define your twin to be a person that is equally old as you are. just for fun, not seriously, but for fun.
Let's say that KellyJay and I are twins. We have the exact same age. Okay? Simple enough.
We live in the same time frame and we share the same age, as we did from our birth and will have to the time when one of us dies. We are twins.
But let's say that I, KellyJay's twin, am going for a space ride in relativistic velocity. What will happen? Say I'm from earth out in the black two years his earth time, and one year my ship time. So before the space ride we were both, say 25 years of age. But when I return I am 26 year and KellyJay is 27 years.
Does he have a twin? No he hasn't. Neither do I. Why? Because we are not the same age anymore. Where did his twin go? Where is he?
He enters a room. I enter the same room. But we are one year apart. Even if I am in the same room, I am not his twin, because I have not the same age as he has. Right? To see his twin he has to wait one year until I enter the room with his age. And then he has aged another year. He sees me, bu it's not his twin anymore.
Were is his twin? Answer: According to KellyJay, in another timeframe. I, his twin has vanished from his universe, and another person has entered in my place, a non-twin which has an age one year less than his. I see a future KellyJay, he sees an ancient me.
I think this is what KellyJay means when he talking about people and things popping out of his timeframe and another thin or person poppin in, not the same, but with another age.
This is just an experiment. We all know that we only have one timefrme, and the time moves with different speeds because of different spacial velocities, different accellerations, or different gravitational fields.
I stick with the common definition of twins, times, timeframes, time dilation, relativity theory, and all. To change these definitions, we have to rethink everything from its base and up. Why do that, when our current definitions worls so well?
Originally posted by AThousandYoungVery lame reason to keep saying something that may not be true.
[b]why do you think it time and not some physical dilation with the same factors?
Does it matter? It's simply about definitions. You don't like physicists calling their variable "time"...ok. Well, that's what they call it in physics. You don't have to like it but that's the convention.
Imagine trying to force the electrical engineering co ...[text shortened]... t not going to happen, and it doesn't ned to happen. The engineering works either way.[/b]
Kelly