Relativity Experiment - how fast are we really moving?

[TheBigDog]

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

[Tormod]

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.

 

I think there is a misunderstanding here. If you fired 6 rockets away from a satellite, in space, far away from gravity sources, they would all fly away from the satellite and *never* stop. There is nothing to stop then.

 

We could then determine earths absolute velocity and direction of travel by comparing our position to the satellite.

 

We know this already. There is no "absolute velocity" in this respect (unless we bring in the speed of light). The speed of the Earth is a simple geometric calculation. We know the average orbit of the Earth, and we know how long the Earth spends per orbit. The calculation is fairly simple: 2xPixr gives us the circumference of a circle (let's assume that the orbit is circular enough for simplicity. The maths work out more correctly if you use formula for elipses).

 

The mean distance from the Earth to the Sun is about 150,000,000 kilometers, so the distance travelled in a year is 942,000,000 km. Divided by 365 days and then by 24 hours gives an estimated speed of 107,000 km/h (or 67,000 miles/h if you prefer).

 

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

 

It might be a valid experiment but it would be a lot of work to achieve something we already know. And it seems to me it is based on false premises (as stated above) so I think it needs some more work.

[TheBigDog]

Yes, we can calculate the speed of the earth as it orbits the sun. But the sun is not stationary. It is orbiting the the center of the galaxy. And the galaxy is not stationary. It is doing whatever galaxies do.

 

I am trying to devise an experiment that would account for all of those factors and more in determining our absolute speed and direction. Once that was known we would be better able to understand what we observe in the heavens.

 

Shouldn't there be a condition of zero speed, and anything in that condition would experience time in its unaltered frame? Time there would pass at its maximum (fastest) relative rate. It would be the opposite of the speed of light. If that condition exists then we can find our absolute speed in the universe. I am proposing that we can find how far we are from that by sending rockets in all directions and observing which rocket(s) approach a speed of zero.

 

Bill

[kamil]

This experiment would prove relativity of simultaenity rather than the existence of an absolute rest.

BTW, if you are talking about time dilation you can't even assume that absolute rest exists, since that is one of the ideas where time dilation comes from.

[TheBigDog]

This experiment would prove relativity of simultaenity rather than the existence of an absolute rest.

BTW, if you are talking about time dilation you can't even assume that absolute rest exists, since that is one of the ideas where time dilation comes from.

Assume for a moment that the sun is still in space. The sun is orbiting the earth, so it has speed and direction prior to the launch of the satellite. For the satellite to have gotten into deep space it had to be sent there. So it was travelling faster than both the Earth and the Sun prior to launching he rockets. The satellite had accelerated from earth, so its time was slower than when it was launched. It launches the rockets. One of the rockets is pointed directly back where the satellite came from. When it shoots from the satellite it is in fact slowing down to the speed of the earth. So while it is accelerating from the satellite, it is slowing in relative space - thus time will be moving faster on the rocket than on the satellite. The rest of the rockets exceed the speed of the satellite by accelerating either along the same path or perpendicular to its path - thus time slows on all of those rockets.

 

If this is not true then the universe only allows for acceleration, not deceleration. Relative speed cannot only add up - it must go down as well.

 

Bill

[kamil]

If this is not true then the universe only allows for acceleration, not deceleration.

 

Bill

 

If you are moving on a really fast train, you do not know it is moving, if the train then suddenly comes to a halt, you think that the train has accelerated, whereas the people on the train station think it has decelerated.

 

U said:'Assume for a moment that the sun is still in space'

 

All inertial observers are still in space according to themselves. Galilean relativity shows that if I said that the somputer screen infront of me is always on co-ordinate x=1, then for somebody standing on the moon it seems as though the co-ordiante at which the screen is located keeps on changing.

So you see space is measured differently to different inertial frames even according to Galilean relativity.

[kamil]

I must say that this experiment will show time dilation and relativity of simultaenity, from the light beams moving infront of the ship and behind the ship you can derive relativity of simultaenity, and by analyzing the other light beams you can derive time dilation.

[Boerseun]

This is a mechanical version of the Michaelson/Morley experiment.

 

As far as the satellite is concerned, it's at absolute rest. It cannot be more at rest than it is. Unless you use some other body as reference. After the rockets have finished firing, and they're coasting, the same applies to them. The satellite is moving 'away' from them, because each and every rocket will also be at 'absolute rest', as far as they're concerned.

 

The rockets will see the satellite contract, and the satellite will see the rockets contract. There is no way here to determine anything regarding 'absolute rest' for anything. Everything is at rest compared to themselves. Yeah - that sounds kinda stupid - but, hey, it's the truth.

[TheBigDog]

This is a mechanical version of the Michaelson/Morley experiment.

 

As far as the satellite is concerned, it's at absolute rest. It cannot be more at rest than it is. Unless you use some other body as reference. After the rockets have finished firing, and they're coasting, the same applies to them. The satellite is moving 'away' from them, because each and every rocket will also be at 'absolute rest', as far as they're concerned.

 

The rockets will see the satellite contract, and the satellite will see the rockets contract. There is no way here to determine anything regarding 'absolute rest' for anything. Everything is at rest compared to themselves. Yeah - that sounds kinda stupid - but, hey, it's the truth.

I appreciate the feedback, but there is a paradox here. Let me see if I can explain it correctly...

 

A space station is out in empty space. It launches a satellite that achieves a speed of .1c as it moves away from the space station. The speed of the satellite is confirmed by radar. The time dilation is measured on the satellite relative to the space station. This is done by sending a radio signal from the station to the satellite. The signal bounces off the satellite and returns to the station. A sensor on the satellite sends out its own signal exactly one second after it detects the signal from the station. Back on the station they detect the two signals. First the return of their own signal, and then the answer from the satellite. If the two bodies were in the same time frame then the signals would be exactly one station second apart. But they are not in the same time frame, the second signal returns after one satellite second plus the amount of time it takes radio waves to travel the distance covered by the satellite during one satellite second. Knowing the speed of the satellite you can determine the difference in time on the satellite versus on the space station. A second is longer on the satellite because its speed is closer to light speed.

 

The satellite is taking the same measurement of the space station. When its signal hits the space station it bounces back toward the satellite. One station second later a signal is sent to the satellite. In the frame of the satellite the station signal would arrive less than a second after the bounced signal. Even thought it would appear that the space station was moving away from the satellite as described by Special Relativity, the information from the space station's clock would allow the satellite to understand that it had been accelerated.

 

Here is the paradox that exists if you cannot find a state of absolute rest...

 

The satellite launches a rocket toward the space station. It accelerates to a speed of .1c. The satellite measures the rocket's speed and time the same way it measures the space station's speed and time. It should measure one rocket second as being longer that one satellite second. But the rocket is now moving at the same speed in the same direction as the station. So rocket time is equal to station time - but the satellite should record the station time as being faster and the rocket time as being slower.

 

My experiment would hope to demonstrate that the satellite would see the time on both the rocket and the space station as being equal, and both faster than on the satellite. By doing this not on a single line as above, but in three dimensions, you could correlate the relative times on the various rockets to determine how they vary from absolute rest. This would let you show your true speed and direction in the universe. All of this is invisible to the Michaelson/Morley experiment because it only samples in one time frame.

 

Bill

[kamil]

 

A space station is out in empty space. It launches a satellite that achieves a speed of .1c as it moves away from the space station. The speed of the satellite is confirmed by radar. The time dilation is measured on the satellite relative to the space station. This is done by sending a radio signal from the station to the satellite. The signal bounces off the satellite and returns to the station. A sensor on the satellite sends out its own signal exactly one second after it detects the signal from the station. Back on the station they detect the two signals. First the return of their own signal, and then the answer from the satellite. If the two bodies were in the same time frame then the signals would be exactly one station second apart. But they are not in the same time frame, the second signal returns after one satellite second plus the amount of time it takes radio waves to travel the distance covered by the satellite during one satellite second. Knowing the speed of the satellite you can determine the difference in time on the satellite versus on the space station. A second is longer on the satellite because its speed is closer to light speed.

 

Bill

 

This is how Einstein pictured relativity of simultaenity, though your version is a bit more complicated because there are three bodies moving at different speeds. But bassically, when the signal hits the satelite, the space station will measure that the light signall hit the station at a certain time co-ordinate, but the sattelite will measure that the signal hit it at a different time co-ordinate. this will happen not only because of time dilation but because of relativity of simultaenity as well:

 

t'=(t-vx/c^2)gamma

 

Is the formula for measuring time co-ordinate for diferent inertial frames. (Where t=0 and t'=0 are simultaenous). This formula comes from a hypothetical experiment similair to yours, where a combination of time dilation and ther two postulae of relativity are used to derive it.

Basically relativity of simultaenity resolves all the confusion that comes form relativity when we are talkign about light beams moving in different directions.

 

but the satellite should record the station time as being faster and the rocket time as being slower.

 

Bill

 

Time will always be measured as moving slower in a different inertial frame, never faster.

[TheBigDog]

Well, with the help of a spreadsheet and some references to formulas, I have made myself a "Relativity Calculator". With that as a tool I began to play out my experiment as best I can. I am going to share what I learned here.

 

Step 1 - the calculator

 

I used a very common spreadsheet. Any will do, the formulas are basic enough.

 

Cell A1 = initial Velocity as fraction of c

Cell A2 = additional Velocity as fraction of c

Cell A3 = relative sum of velocities as fraction of c = (A1+A2)/(1+(A1*A2))

Cell A4 = Gamma formula = 1/sqrt(1-(A3^2))

Cell A5 = Time from echo to response in rest seconds = (1+A3)*A4

 

Cell B1 = A3

Copy Cells A3, A4, A5 to B3, B4, B5

Fill B1 to B5 to the right a few times

 

A1 is the intial velocity

A2 is velocity added to A1

Put additional values to add in B2, C2, etc

 

Step 2 - the experiment

 

The universe is at rest (A1 = 0)

The space station is (relativly) at rest (A2 = 0)

The satellite was launched west from the space station (B2 = .2)

The rocket was launched west from the satellite (C2 = .2)

 

0 0 0.2

0 0.2 0.2

0 0.2 0.38461

1 1.02062 1.08333

1 1.22474 1.5

 

What this shows is that from each point of view, the same accelleration appears to have taken place, even though there is a declining amount of actual speed. This is because of time dilation. On the station, the satellite appears to be moving at .2c and the rocket at .38461c. From the satellite both the station and the rocket appear to be moving at .2c in opposite directions. In the experiment, the station bounces a signal off both the satellite and the rocket. The satellite and rocket each wait one local second before sending a return signal. At the station the echo from the satellite arrives 1.22474 seconds before the response. The echo from the rocket arrives 1.5 seconds before the response. The delay is calculated by length of a local second plus the length of time for the response signal to travel the distance covered by the satellite or rocket during that local second.

 

Note that 1.22474/1 = 1.5/1.22474 indicating that the perspective from station to satellite = perspective of satellite to rocket. Rocket to satellite looks same as satellite to station.

 

Step 3 - Adjust the station speed

 

Now I put in an initial speed for the station (A2 = .5)

 

0 0.5 0.63636

0.5 0.2 0.2

0.5 0.63636 0.74193

1.15470 1.29636 1.49148

1.73205 2.12132 2.59807

 

Now the station is moving at a speed of .5c. The from the station the satellite appears to be travelling at .2c, but has an actual speed of .63636c. From the satellite the rocket appears to be travelling .2c, but has an actual speed of .74193c.

 

Now lets look at the echo/response times. 2.12132/1.73205 = 2.59807/2.1.132 AND = 1.22474/1 = 1.5/1.22474 - so even though the inital speed was changed - from any perspective in the experiment there is no way of measuring that fact! It would seem that there is no way of telling if you are at rest of if you are travelling .99c!

 

If I am on the station, and I measure the speed of the satellite from the station at .2c, I know that the gamma of .2c is 1.02062. So 1 satellite second = 1.02062 station seconds. I can verify this by removing the light speed travel time that happened during 1 satellite second of travel from the echo/response time from the satellite to arrive at exactly 1.02062 seconds or 1.22474 - (.2 * 1.02062) = 1.22474 - .20412 = 1.02062).

 

Then I repeat the same exercise from the point of view of the satellite to the rocket. From the satellite to the rocket I observe that the rocket is travelling at .2c. The gamma of .2c is 1.02062. So 1 rocket second = 1.02062 satellite seconds. Now I repeat the same exercise as above. The measured echo/response is 1.22474 satellite seconds. 1.22474 - (.2 * 1.02062) = 1.22474 - .20412 = 1.02062).

 

Now lets look at the measurement from the station to the rocket. The observed speed is .38461c. The gamma for .38461c is 1.08333 with an echo/response time of 1.5 seconds. Our formula for correcting for the travel time of the rocket is 1.5 - (.38461 * 1.08333) = 1.5 - .41666 = 1.08333.

 

Now lets turn it around and see how the space station looks from the satellite. The station appears to be travelling at .2c with a gamma of 1.02062. So 1 station second = 1.02062 satellite seconds. But the gamma of the space station is 1, as it was "at rest" and the starting point of all these objects. The values are turned on their heads because you cannot tell which of the objects was the one accellerated. So the echo/response from station to satellite is 1.2 station seconds. We convert that to satellite seconds and we get 1.2 * 1.02062 = or 1.22474 seconds. Same as going the other direction. And even though time is moving slower on the satellite than on the station, it appears from both perspectives that the other is where time is moving slower.

 

Well that tool longer than I anticipated, and if anyone has read this far they probabaly need a cup of coffee. But what is shows is that my fellow Hypographers were correct. You just can't tell.

 

But I have not given up.

 

Bill

[lindagarrette]

There is no way here to determine anything regarding 'absolute rest' for anything. Everything is at rest compared to themselves. Yeah - that sounds kinda stupid - but, hey, it's the truth.

I agree. There is no way to determine absolute rest since, quantumly speaking, an object at rest would have no mass, and would not exist. So, nothing is at absolute rest, at least as long as the universe is expanding. In space/time reality, all bodies are travelling away from each other at some speed that can be measured by an observer. Granted, the observer has to consider his position fixed, but it really isn't. I'm sitting at my computer on the surface of a moving object. The planet is rotating, revolving around the sun, and so on. Eventually, all may be at rest -- the Big Rip theory.

[TheBigDog]

I have played with the math, and I understand that through observation everything appears to itself to be at rest. But to say that there can be no state of absolute rest, or of zero speed simply doesn't ring true to me. So I have played with it some more, and I believe that I can show that a state of rest can be found, and in turn our absolute velocity can be seen as well.

 

First, let me modify the experiment. There is a space station in deep space, far from the reaches of major gravitational bodies. It launches two rockets, one east and one west. They each are moving away from the space station at .2c. After ten years the station sends a signal to each of the rockets asking them to tell how long since they launched. Both rockets return an answer that 9.79795 years have passed. This is due to the time dilation that occurs at .2c.

 

Now we repeat the exeriment with the space station traveling west at .2c at the time that the rockets are launched, from the perspective of the rockets and the space station the experiment is unchanged. But when the answers come back from the rockets the answers are different. Rocket west reports a time since launch of 9.79795 years, but rocket east reports a time since launch of 10.61445 years! This is because the rocket is travelling slower than the space station in absolute speed. This is similar to the classic twins experiment where one twin goes into space at near light speed, and returns years later to find the other twin has grown old while he has barely aged. For the twin to come back and experience the company of the aged sibling, he would need to decelerate - thus returning to the original time frame. Otherwise he would continue to age slowly even though he was moving at earth speed again.

 

You can take this one step further. If the space station is travelling at an unknown speed along a line moving east/west, and does the same experiment, you could find the absolute speed of the space station along that line by comparing the elapsed times returned by the two rockets. And finally by launching 6 rockets each at 90 degrees to each other, so a pair it measureing each plane of 3 dimentional space occupied by the station, you can find the absolute speed and direction of the space station in the universe.

 

So, in any plane, an object is travelling as a speed between -c and c. When an object is at a speed of 0 in all three planes it is at rest in the universe, and experiences time at its absolute (fastest) speed.

 

So is this right, or have I made a mistake?

 

Bill

[kamil]

This is similar to the classic twins experiment where one twin goes into space at near light speed, and returns years later to find the other twin has grown old while he has barely aged. For the twin to come back and experience the company of the aged sibling, he would need to decelerate - thus returning to the original time frame.

Bill

 

But this orginal time frame is the not any more significant from any other time frame besides the fact that its the frame in which the twins met before the experiment(and synchronized thier clocks). In order to compare the elapsed time of two clocks moving at different speeds, we first have to have the two clocks at the same frame in the beginig, and synchronize them to t=0 and t'=0. Otherwise the twin paradox would have no meaning. Therefore no inertial frame is more significant than the other.

[TheBigDog]

But this orginal time frame is the not any more significant from any other time frame besides the fact that its the frame in which the twins met before the experiment(and synchronized thier clocks). In order to compare the elapsed time of two clocks moving at different speeds, we first have to have the two clocks at the same frame in the beginig, and synchronize them to t=0 and t'=0. Otherwise the twin paradox would have no meaning. Therefore no inertial frame is more significant than the other.

Thanks for following my thought with me kamil,

 

When I say original time frame, I mean rate of time passage. My meaning is that all objects travelling at the same velocity are in the same time frame. When the twins are reunited, they have resyncronized their speed thus returning to the same time frame. In the interim they had experienced radically different speeds and so the amount of elapsed time was different for each twin.

 

In my experiment all the rockets and the space station have syncronized clocks at the beginning. Using the mathmatics of special relativity I know how they observe each other in their own time frame, regardless of the initial velocity of the space station, is always the same. But by compating the multiple observations of total time passage you find the differing GAMMA values that indicate the different effect that special relativity has on each object.

 

What am I doing wrong?

 

Bill

[arkain101]

I posted about this very similar experiment.

 

 

(this experiment can best be invisioned by picturing a particle accelerator being tested by shooting a rather easily detectable particle in all 3 dimensions [foward back, left right, and up down] to test for velocity constraints from an absolute rest/absolute speed.)

 

<<<Authentic SR experiment in the SR considered Universe.

The object in the middle represents the point of which the test is performed (d). Its velocity is an unknown. But is our rest frame for the experiment. Any object that goes in one of the directions can only go as fast as .9999c with our device, the velocity maximum Vm. So as an object travels down a plane this picture shows we grow a line to its speed and direction on this 2dimensional plane. I cant draw a 3-dimensional graph.

Now on this point ( center - d ) of which the test is performed we send an object (p) in each of the four direction(a, b, c ,d) at our Vm of 0.999999C "for example" (Velocity maximum- Vm -in reference to d).

 

We compare p's velocity constrained, "Vc", with the other directions (we consider that since "d" is at a velocity [earth] but unkown to space (s), that one direction of Vm should verify where a constraint of Vm is detectable in reference to d). After testing a,b,c,d diretions. Vc (constrained velocity total of p in reference to d) should be different on all planes (if d is in motion which it is). Derive the Vc's to consider velocity of d in relation to s (spacetime), and direction of travel in rest frame of s.

 

 

-logically P will go Vc less than C in one direction and Vc greater than C in another direction if d is at a significant velocity in reference to S.-

 

 

 

The experiment intends to show whether Spacetime constrains matter at a limit, or if the limit is due to the Velocity maximum of the device(particle accelerator), and to use this data to represent The velocity and direction of d and from there repeat equations to show d's characterists in refernece of absolute rest of s.

 

If SR is true, results should show Vc's, and if so those Vc's can break down the direction and Velocity path of d (earth where particle acclerator resides), from there showing V of d and its direction of travel in relation to Space.

 

If SR is false, results should show No Vc's. and no absolute rest will be necessesary as it may show that V does not exist in relation to space-time, but only to the relationship between to reference frames.>>>

 

end of exp.

-----------------------------------------------

 

"response to this thread."

 

However, after some later thinking, I started to see a problem.

 

Time dialation is the difference in time between two moving objects. However there is a paradox of which one should have the time dialtion applied to it. They claim to have solved this by simply applying it to the ojbect that experiences a force. Now this creates a paradox, because if you are applying that one object is attaining more velocity than the other, then you are stating that there is an absolute frame of reference, or inertial frame(?). So if one object can attain more speed than another (knowing this by assuming which one is experiences the acceleration force) then we are assuming one object is going faster than the other in reference to something else, that something else must be space.

 

If you have earth and a space ship. The ship and earth expand apart at 20km/s because the ship blasted away. We are watching from a frame = to rest of earth.. so we see earth stay still and the ship blast away.. It would seem the ship is the moving object.

 

Scenario two.

We are moving in the same direction as the ship... we are at rest.. the earth is moving past us at 20km/s. The ship blasts off and stays in rest in our view, the earth leaves the ship and us at 20 km/sec.

 

Which one should experience time dialation? and according to what, is one of the objects attaining MORE velocity.

 

Light in theory is the same speed to your frame at all times. So no matter what you do light will be its speed. So no matter what something does its world around it will make up for that change, and the world around it will see the object make up for that change, with time, and all those other dialations.

BUt unless we assume there is some kind of absolute rest, the application of dialtions from slow time for (a) and fast time for (B) can be applied to either one. (the twin paradox) seems only to be corrected if we beleive mass is moving through space, but if we dont think mass moves through anything, and all you can do is compare objects then the twin paradox remains intact.

[kamil]

Rocket west reports a time since launch of 9.79795 years, but rocket east reports a time since launch of 10.61445 years! This is because the rocket is travelling slower than the space station in absolute speed.

 

Bill

 

I dont see how you concluded that an absolute speed exists. I dont see any pure logic in your thought proccess. I have read over and over and i cant see the logical proof. Maybe I misunderstood something. Add me on msn, [email protected] so that we can hav a quick Q&A discussion.

 

This is similar to the classic twins experiment where one twin goes into space at near light speed, and returns years later to find the other twin has grown old while he has barely aged. For the twin to come back and experience the company of the aged sibling, he would need to decelerate - thus returning to the original time frame.

 

I suggest you read the thread entitled 'Question about light & relativity' there i explain the solution for the twin paraox.:rainbow: