Relativity Experiment - how fast are we really moving?

[HIENVN]

A satellite is sent into deep space, away from meddling influence of gravity. From that satellite are launched 6 rockets at 90 degree angles to one another. North, south, east, west, up and down. The rockets race away from the satellite into space. The satellite sends a radio pulse out at a regular interval to all of the rockets. Each rocket has a reflector that bounces the signal back the satellite. Each rocket also has a transmitter that sends a radio reply back to the satellite exactly one second after receiving each pulse. The satellite should see that the time between the reflected signal and the replies begin to take longer than a second as the time of the rockets slows.

 

BUT, that effect would only be true if the satellite were nearly at rest when the rockets were fired. All things in motion, at any speed, have some very small time dilation. I understand the the earth is moving at very great speed, but we don't feel it because we are along for the ride. The rockets launched from the satellite would be going in all directions. So at lease one of the would be decelerating as it moved against its absolute direction of travel in the universe. That rocket would actually be slowing down as it appeared to accelerate away from the satellite. The reply to the satellite would come in less than a second as time on that rocket actually speeds up as the rocket moves back toward a resting state.

 

If that is true, then the satellite could use triangulation and its knowledge of the time dilation of each rocket to find its absolute velocity and direction of travel in space. We could then determine earths absolute velocity and direction of travel by comparing our position to the satellite.

 

Is this a valid experiment? If not, why not?

 

Bill

 

You have mistake from a condition of "Far away from meddling influence of gravity." The universe is covered by gravitational waves, which are the cause of gravitational waves; therefore, your experiment can not happen.

[Qfwfq]

An important thing to understand Bill is that, if B is moving away from A, 1 second of B will be more than 1 second of A but not just "more than 1 second" period. In fact, the same will be true the other way around: 1 second of A is more than 1 second of B, which is the twin paradox.

 

The subtlety is therefore in the step where you say that, because the satellite is moving, the rocket launched in the forward direction is different from the others. There's really no difference between them and, as Boerseun said, it boils down to the same thing as Michelson-Morely.

 

You have mistake from a condition of "Far away from meddling influence of gravity." The universe is covered by gravitational waves, which are the cause of gravitational waves; therefore, your experiment can not happen.

Wha? :)

[Shekhar]

There is no time dilation as all speeds or velocities are relative ........if a rocket is moving with some speed then earth is also speeding back for rocket.

 

Time dilation has some other cause in my views........I will soon try to present it to all

[Tormod]

There is no time dilation as all speeds or velocities are relative ........if a rocket is moving with some speed then earth is also speeding back for rocket.

 

Time dilation has some other cause in my views........I will soon try to present it to all

 

Time dilation is *caused* by relative speeds so I am looking forward to your presentation.

[Shekhar]

Time dilation is *caused* by relative speeds

 

I think time dilation is psychological experience taking relative speed in concern.

 

Because speed gets different value if we keep changing reference frames........is time dilation relative ?

[Tormod]

Time dilation is very real. GPS systems need to calculate for the dilation caused by the speed they have in space. It is very small but still large enough to cause errors if the signal is not corrected for time dilation.

 

How does this translate to your claim that time dilation is a "psychological experience"?

[Shekhar]

GPS systems need to calculate for the dilation caused by the speed they have in space.

 

Sir,

There can be a frame of ref. where the speed of GPS system is 0 relative to it.

 

Now, does dilation has any link with speed ?

[InfiniteNow]

Perception of time in the temporal and parietal regions of the brain, and observing a device which measures time as dilated are two very distinct phenomena. We sense our own passage through time, and this sense can be impacted and altered (chemically for example). However, the impact of velociy on the passage of time has also been measured using incredibly accurate sensors and clocks, which indicates to me that it is more than *just* psychological. :eek2:

 

 

Cheers. :lightning

[TheBigDog]

WOW! A thread from the past. I have been waiting to open this discussion up again. Maybe now is a good time. The basic premise I am getting at is this...

 

In the twin paradox the twins eventually get back together. And when they do so it become apparent that one of them has traveled further than the other, thus different experience of time passage. I am extending this to saying that we already have a speed and direction in the universe that we are perceptually unaware of. With the correct experiment we could determine what that speed and direction is. But it requires a broad experiment with geometrically opposed targets traveling at relativistic speeds. Some of those will be moving in our direction of travel, and as a result they will be moving faster and dilating time more. The opposite one would be decelerating and moving slower than us, and thus dilating time less.

 

If those object accellerated forever, they would all approach light speed. But the ones aimed bakcward would first decelerate to universal rest speed, before accelerating toward light speed. Finding that would allow us to measure the universes absolute time. It is a geometric absolute, as far as I understand the process of time dilation.

 

Bill

[Janus]

WOW! A thread from the past. I have been waiting to open this discussion up again. Maybe now is a good time. The basic premise I am getting at is this...

 

In the twin paradox the twins eventually get back together. And when they do so it become apparent that one of them has traveled further than the other, thus different experience of time passage. I am extending this to saying that we already have a speed and direction in the universe that we are perceptually unaware of. With the correct experiment we could determine what that speed and direction is. But it requires a broad experiment with geometrically opposed targets traveling at relativistic speeds. Some of those will be moving in our direction of travel, and as a result they will be moving faster and dilating time more. The opposite one would be decelerating and moving slower than us, and thus dilating time less.

 

If those object accellerated forever, they would all approach light speed. But the ones aimed bakcward would first decelerate to universal rest speed, before accelerating toward light speed. Finding that would allow us to measure the universes absolute time. It is a geometric absolute, as far as I understand the process of time dilation.

 

Bill

The thing is, your experiment is already being done, every day, and in labs all around the world. Particle colliders accelerate particles up to near light speed all the time. They point in different directions form each other and even change the direction they point as the Earth rotates.

 

If your test actually were capable of finding an absolute universal rest, and the Earth's motion with respect to it, we'd know it by now. For example, in a typical collider experiment, a particle is smashed into target and lot's of secondary particles are created and scatter from the target. Many of these particles are very short lived, and are only detectable because, at their relativistic speeds, they are time dilated. Since soem these particles would be traveling in the same direction as the Earth's motion, and some in other directions, we would see these particles lasting for different times depending on which direction they travel. With the vast number of these experiments performed over time, a pattern would arise, indicating the Earth's motion through absolute space.

 

The truth of the matter is that these experiments do not show any pattern of this type. No matter which direction the collider is pointed, the secondary particles lifetimes only depend on their relative velocity to the lab. There is no difference that indicates any absolute motion of the Earth.

 

 

In SR there is no absolute rest, and time dilation does not rely on it.

 

Go back and check out the post I made in the other thread on Relativity. (The one with the animations) . Note that in the animations it does not matter who is considered at rest, the results come out the same. If there were an absolute rest, the the end results would depend on which object or frame is at rest.

[TheBigDog]

Thanks for the reply Janus. I have read your excellent posts on relativity. Maybe I am just hitting a rational wall of sorts. I need to chew on this for a while and will come back to this later.

 

Bill

[Qfwfq]

Janus' point is qualitatively correct... there would be a 24h variation in the masses of collider data, compared with the expectations of phenomenologists work, but alas! I must play the devil's advocate, the amplitude would probably be unnoticeably small... unless you imagine Earth's absolute velocity to be a significant fraction of c.

 

My argument is simply that, if you do the homework properly, the well-verified Lorentz-covariant dynamics don't afford a way of detecting such a thing. Craig has much more patience than I do, for posting the necessary algebra, but I'll try to get round to it.

[TheBigDog]

Once more I dip my ladle into into the well of knowledge known as Hypography...

 

I have three clocks that run at the same speed. I take them to a train station. I leave one in the station and board the train with two others. As the train leaves the station as relativistic speed the clock in the station is now recording time faster than the two clocks I have with me on the train. For the sake of simplicity time on the train is half the speed of time at the station. After two hours of station time, the train has experienced one hour of time, where it reaches the next station. I drop one of the remaining clocks out the window and it lands gently in the station that we pass. Now it is traveling at the same speed as the clock in the first station, but is one hour behind. Meanwhile the clock on the train with me continues to run at half the speed of the other two clocks.

 

Each clock saw the others as accelerating. When the train left the first station, the clock on the station saw two clocks accelerate away. The two clocks on the train saw the clock in the station accelerate away. When I got to the second station the clock on the train saw the clock I threw accelerate away, while the clock I threw saw the clock on the train accelerate away. All objects see themselves as being at rest compared to the rest of the universe, and this is observation is proven by SR. But then according to that premise, the two clocks in the stations should not be running at the same rate at the end of the experiment. If they are in fact running at the same rate then we should be able to use experimentation to find our absolute velocity.

 

Here are he clocks in a crude diagram...

 

Three clocks together

:lol: 1:00

:) 1:00

:) 1:00

 

Two clocks leave on a train and travel for two hours as measured by the first clock

:clock: 3:00

------------------->:clock: 2:00

------------------->:clock: 2:00

 

After the above measurement one of the clocks is tossed into a station. We take another measurement 2 hours later as measured by the first clock.

:clock: 5:00

_________________ :clock: 4:00

--------------------------------------->:clock: 3:00

 

Am I good so far?

 

Bill

[TheFaithfulStone]

But then according to that premise, the two clocks in the stations should not be running at the same rate at the end of the experiment. If they are in fact running at the same rate then we should be able to use experimentation to find our absolute velocity.

 

If clocks 1 & 2 are stationary relative to each other (as they appear to be here) then they share a reference frame, and would run at the same speed.

 

TFS

[CraigD]

… We take another measurement 2 hours later as measured by the first clock. …

An important question is “who/what are we” – or rather “where are we?” Is it possible that we are at all 3 clocks simultaneously? (I don’t want to say very much, as it appears you’re close to one of the more enjoyable “ah ha” moments of SR)

[Janus]

Here are he clocks in a crude diagram...

 

Three clocks together

:) 1:00

:circle: 1:00

:circle: 1:00

 

Two clocks leave on a train and travel for two hours as measured by the first clock

:xparty: 3:00

------------------->:friday: 2:00

------------------->:hihi: 2:00

 

After the above measurement one of the clocks is tossed into a station. We take another measurement 2 hours later as measured by the first clock.

:lol: 5:00

_________________ :clock: 4:00

--------------------------------------->:clock: 3:00

 

Am I good so far?

 

Bill

 

As CraigD has already pointed out, this really depends upon who's doing the measurement.

 

An additional hint: You are assuming that the events "clock 1 reads 3:00" and "clocks 2&3 reach the station", happen simultaneously according to all three clocks. This is not an assumption supported by SR.

[Boerseun]

You don't even have to get trains running at relativistic speeds.

Atomic clocks have been flown in commercial airliners around the world, and upon getting back to the lab where the control clock is hanging, quite clearly shows the effect of time dilation on the clock that went up in the airplane.

But all it says is that the clock that went on the plane trip was moving in relation to the one that stayed in the lab. You can't infer any static reference frame out of it - only that the two clocks used to share a reference frame, then didn't for a while, and then upon reuniting, showed a difference.