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Drakes

relative motion (split from Switching frames Lorentz transform.)

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21 minutes ago, swansont said:

Bob is stationary in his frame. You always need to realize what frame you are in when analyzing.

Isn't everything in motion?  The Earth spins on it's axis, the Earth spins round the sun, the Sun spins round the galactic core and the galaxy itself is in motion set by the big bang, it is not known if the universe itself may be moving or vibrating as well.  So to be stationary one would need to understand all frames of motion exactly and counteract each one exactly and since galactic motion can only be estimated stationary from a human perspective is just not possible

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46 minutes ago, Drakes said:

Isn't everything in motion?  The Earth spins on it's axis, the Earth spins round the sun, the Sun spins round the galactic core and the galaxy itself is in motion set by the big bang, it is not known if the universe itself may be moving or vibrating as well.  So to be stationary one would need to understand all frames of motion exactly and counteract each one exactly and since galactic motion can only be estimated stationary from a human perspective is just not possible

Not a very useful line of thinking for homework help.

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1 hour ago, Drakes said:

Isn't everything in motion?  The Earth spins on it's axis, the Earth spins round the sun, the Sun spins round the galactic core and the galaxy itself is in motion set by the big bang, it is not known if the universe itself may be moving or vibrating as well.  So to be stationary one would need to understand all frames of motion exactly and counteract each one exactly and since galactic motion can only be estimated stationary from a human perspective is just not possible

All inertial frames are equivalent. Anyone in an inertial frame can assume they are at rest.

Non-inertial motion is not relative, but can be ignored if the effects are small.

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20 minutes ago, swansont said:

All inertial frames are equivalent. Anyone in an inertial frame can assume they are at rest.

Non-inertial motion is not relative, but can be ignored if the effects are small.

Define small effects as determined by a galactic or universal scale and why would something small be irrelevant.

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8 minutes ago, Drakes said:

Define small effects as determined by a galactic or universal scale and why would something small be irrelevant.

In experiments we get quantified results, with a limit on the precision. If the effect is smaller than that limit, it will not affect the answer.

IOW, if your result is e.g. 114 +/- 1, an effect that would change this by 0.001 can be ignored.

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4 minutes ago, swansont said:

In experiments we get quantified results, with a limit on the precision. If the effect is smaller than that limit, it will not affect the answer.

IOW, if your result is e.g. 114 +/- 1, an effect that would change this by 0.001 can be ignored.

And what is the speed and direction of this galaxy and how is this measured with precision from a humans frame on Earth so that you can pop that speed into an equation and be certain that the speed is correct because without a correct speed the equation is meaningless.  Would an error of 1 mile per hour effect the distance traveled over say a billion years?

Yes it would.

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10 minutes ago, Drakes said:

And what is the speed and direction of this galaxy and how is this measured with precision from a humans frame on Earth so that you can pop that speed into an equation and be certain that the speed is correct because without a correct speed the equation is meaningless.  Would an error of 1 mile per hour effect the distance traveled over say a billion years?

Yes it would.

But the question is, is this difference significant compared to what you are measuring.  If the difference is between traveling at 600,000,000 miles per hr and 600,000,001 mph, the the difference in distance traveled in a billion years is insignificant compared to the total distance traveled (a difference of ~ 1.5 ly over 900,000,000 ly)

But more importantly it's insignificant if you are trying to test between two models that give answers that differ by over 100,000 ly, for example.

 

But the main point that swansont was making is that there is no object in the universe has an "absolute" velocity, All velocities are relative.  There would be no difference in the answers you get by assuming the galaxy has zero velocity and the galaxy having a velocity of 180,000 miles per sec.   The effects Swansont refer to are the non-inertial ones due to things like Earth's gravity, etc. And those can be directly measured and accounted for.  With the experiments he is talking about, these things have very small influence compared to the size of the effect we are measuring.  It's like gravity accounting for the 1.5 ly difference above, when you are looking for the 100,000 ly difference.

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Just now, Janus said:

But the question is, is this difference significant compared to what you are measuring.  If the difference is between traveling at 600,000,000 miles per hr and 600,000,001 mph, the the difference in distance traveled in a billion years is insignificant compared to the total distance traveled (a difference of ~ 1.5 ly over 900,000,000 ly)

But more importantly it's insignificant if you are trying to test between two models that give answers that differ by over 100,000 ly, for example.

 

But the main point that swansont was making is that there is no object in the universe has an "absolute" velocity, All velocities are relative.  There would be no difference in the answers you get by assuming the galaxy has zero velocity and the galaxy having a velocity of 180,000 miles per sec.   The effects Swansont refer to are the non-inertial ones due to things like Earth's gravity, etc. And those can be directly measured and accounted for.  With the experiments he is talking about, these things have very small influence compared to the size of the effect we are measuring.  It's like gravity accounting for the 1.5 ly difference above, when you are looking for the 100,000 ly difference.

The orbital speed of the Milky way is estimated at one orbit in every 225 to 250 million years. We are in this orbit and the speed can not be guessed any better than that.  Then there is the linear speed of the Milky way which can only be guessed with even less precision, however the actual speed is so out of frame to a human observer that any supposedly accurate speed can be popped in and called a scientific theory, it's not a theory it's a guess though I suppose the terms can be interchanged.  Then there is the stability of the Universe itself which might be stable or it might be orbiting, moving linear or vibrating.  My point is that from our frame and solo point of view there is no way to be still or know what speeds that would all need to be counteracted to achieve motionless.  Claiming that errors do not matter, is completely silly, but is easy on the internet when your O2 supply is not limited I suppose.

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21 minutes ago, Drakes said:

The orbital speed of the Milky way is estimated at one orbit in every 225 to 250 million years. We are in this orbit and the speed can not be guessed any better than that.  Then there is the linear speed of the Milky way which can only be guessed with even less precision, however the actual speed is so out of frame to a human observer that any supposedly accurate speed can be popped in and called a scientific theory, it's not a theory it's a guess though I suppose the terms can be interchanged.  Then there is the stability of the Universe itself which might be stable or it might be orbiting, moving linear or vibrating.  My point is that from our frame and solo point of view there is no way to be still or know what speeds that would all need to be counteracted to achieve motionless.  Claiming that errors do not matter, is completely silly, but is easy on the internet when your O2 supply is not limited I suppose.

There is no such thing as absolute "motionlessness" to achieve.   The Solar system orbits relative to the center of galaxy.  we can give its speed relative to this center.  The Earth orbits relative to the Sun.   Our galaxy has a velocity relative to the center of gravity of the local group.  The local group has a relative velocity larger galactic cluster it is a part of...

But none of these motions are with respect to some absolute state of "rest", as no such state exists, and it is meaningless to talk about one.  You can only consider velocities as being measured relative to some reference. And any reference you chose is just as valid as any other.  Thus you are free to choose whichever one is the most convenient to work from.  If the one where you consider yourself or anything else as being at rest is best for your purposes, you are free to use it.

If you have a velocity of 100 mph relative to me, it is the same as I having a 100 mph velocity relative to you, and that is as far as it can go. There is no absolute rest frame that either or both of us are "really" moving with respect to.

 

 

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9 hours ago, Drakes said:

And what is the speed and direction of this galaxy and how is this measured with precision from a humans frame on Earth so that you can pop that speed into an equation and be certain that the speed is correct because without a correct speed the equation is meaningless.  Would an error of 1 mile per hour effect the distance traveled over say a billion years?

Yes it would.

The linear speed is irrelevant since inertial frames are equivalent.

Distance isn’t the variable in the relativity effects. Speed is. The only error term here is the deviation from a linear velocity, which is very small. Feel free to calculate the Sagnac effect results and see for yourself.

And if it’s small, the exact value doesn’t matter, since it can be ignored.

8 hours ago, Drakes said:

Claiming that errors do not matter, is completely silly

On the contrary, claiming that errors that are demonstrably smaller than your precision matter is what’s silly.

As with the numbers Janus used - if you are looking for a 100k LY effect, not accounting for 1.5 LY isn’t going to matter.

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Posted (edited)
10 hours ago, Janus said:

There is no such thing as absolute "motionlessness" to achieve.   The Solar system orbits relative to the center of galaxy.  we can give its speed relative to this center.  The Earth orbits relative to the Sun.   Our galaxy has a velocity relative to the center of gravity of the local group.  The local group has a relative velocity larger galactic cluster it is a part of...

But none of these motions are with respect to some absolute state of "rest", as no such state exists, and it is meaningless to talk about one.  You can only consider velocities as being measured relative to some reference. And any reference you chose is just as valid as any other.  Thus you are free to choose whichever one is the most convenient to work from.  If the one where you consider yourself or anything else as being at rest is best for your purposes, you are free to use it.

If you have a velocity of 100 mph relative to me, it is the same as I having a 100 mph velocity relative to you, and that is as far as it can go. There is no absolute rest frame that either or both of us are "really" moving with respect to.

 

 

Einsteins so called thought experiment is called a thought experiment because it can not be conducted as a real experiment.  Now if you are in the ocean and the current is exerting a 10 knot force on the vessel and enough power is applied to match the 10 knot current and facing into the current then the force is balanced and the vessel remains motionless, or so it seems until you factor in the Earths spin, the Suns galactic rotation and  then galactic linear travel.  The error magnifies with each growing step. knowing the Earths spin, and rotation around the sun can be calculated because error checking to the previous time frame can be compared and errors worked out.  When considering the Suns orbit around the galactic core the projected error is plus or minus 25 million years in a 225 to 250 million year rotation that can not be error checked to the previous orbit because humanity has never seen an entire orbit and may never and there is still at least one more movement thru spacetime not accounted for.  Those who tried to work out the math have all concluded that the universe as observed is wrong as 85 percent is missing.  Dark matter is at current not real, it is a variable that makes an equation correct, so without the right data to apply no calculations to remain still for Einsteins thought experiment are viable as there are just too many unknowns and as such we are actually lost on island Earth.  However this will not stop the geniuses at the page with three entire users from controlling the flow of spacetime with their own distorted reality.

Edited by Drakes

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Posted (edited)
1 hour ago, swansont said:

The linear speed is irrelevant since inertial frames are equivalent.

Distance isn’t the variable in the relativity effects. Speed is. The only error term here is the deviation from a linear velocity, which is very small. Feel free to calculate the Sagnac effect results and see for yourself.

And if it’s small, the exact value doesn’t matter, since it can be ignored.

On the contrary, claiming that errors that are demonstrably smaller than your precision matter is what’s silly.

As with the numbers Janus used - if you are looking for a 100k LY effect, not accounting for 1.5 LY isn’t going to matter.

Again Einsteins observer can not remain motionless unless all motion to the observer is eliminated.  I wonder if Einstein based this experiment in the period of time before Hubble demonstrated that the Universe was not static as Einstein once believed?   

And as Drake predicted there are 3............................... the other 2 out of 7.4 billion on cue as predicted.

 

Another will soon be rustled out of bed

 

As in politics the effort to cover up the truth creates more noise than the truth itself

Edited by Drakes

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1 hour ago, Drakes said:

Again Einsteins observer can not remain motionless unless all motion to the observer is eliminated. 

Motion is relative. How do you determine who is moving?

2 hours ago, Drakes said:

When considering the Suns orbit around the galactic core the projected error is plus or minus 25 million years in a 225 to 250 million year rotation that can not be error checked to the previous orbit because humanity has never seen an entire orbit and may never and there is still at least one more movement thru spacetime not accounted for. 

What effect does this motion have? Pick a some terrestrial experiment and calculate the effect. Then explain why knowing this to better than 10% is necessary 

Are you able to do this?

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3 hours ago, Drakes said:

Again Einsteins observer can not remain motionless unless all motion to the observer is eliminated. 

Since you seem to argue against relative motion, are you confused regarding acceleration?

Acceleration can be measured and sometimes you need to account for it and sometimes not. Experiments performed in for instance an accelerating rocket can of course have a different outcome that the same experiment performed in zero g. But I can't think of an experiment where the solar system's centripetal acceleration relative to the milky way's centre would have impact.

 

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Posted (edited)

 

4 hours ago, Drakes said:

Again Einsteins observer can not remain motionless unless all motion to the observer is eliminated. 

 

True since Earnshaw's theorem also applies to gravitational fields.

So no observer can be motionless.

So once again there is no absolute rest

Quote

 

Edited by studiot

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Posted (edited)

Drakes, can you please tell us what you think an 'inertial frame' is ?
And a non-inertial frame ?

You seem slightly confused.
 

Edited by MigL

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5 hours ago, Drakes said:

Einsteins so called thought experiment is called a thought experiment because it can not be conducted as a real experiment.  Now if you are in the ocean and the current is exerting a 10 knot force on the vessel and enough power is applied to match the 10 knot current and facing into the current then the force is balanced and the vessel remains motionless, or so it seems until you factor in the Earths spin, the Suns galactic rotation and  then galactic linear travel.  The error magnifies with each growing step. knowing the Earths spin, and rotation around the sun can be calculated because error checking to the previous time frame can be compared and errors worked out.  When considering the Suns orbit around the galactic core the projected error is plus or minus 25 million years in a 225 to 250 million year rotation that can not be error checked to the previous orbit because humanity has never seen an entire orbit and may never and there is still at least one more movement thru spacetime not accounted for.  Those who tried to work out the math have all concluded that the universe as observed is wrong as 85 percent is missing.  Dark matter is at current not real, it is a variable that makes an equation correct, so without the right data to apply no calculations to remain still for Einsteins thought experiment are viable as there are just too many unknowns and as such we are actually lost on island Earth.  However this will not stop the geniuses at the page with three entire users from controlling the flow of spacetime with their own distorted reality.

Which thought experiment are you referring to, as there is more than one. 

You keep harping on about "motionlessness" as if it is an absolute, and keep ignoring the fact that everyone is telling you that it isn't.  When any of Einstein's Thought experiments, if the term "at rest" is used, it just means "at rest" with respect to the reference frame from which the experiment is being considered, not "at rest" in any absolute sense.

Put another way.  If you were in a spacecraft off in space far away from any source of gravity and perform one of Einstein's experiments*, You will get a certain result. If you then fire the rocket engine, change your velocity by however much you want, cut off the engines, and repeat the experiment, You will get exactly the same results.  The fact that you have changed velocities between the two experiments will have no effect.  And for the same reason, you don't have to know the Earth's exact motion around the galaxy's center, or the motion of our galaxy with respect to other galaxies, as it will have no effect on the results.

As far as Dark matter goes. The observations that led to its hypothesized existence were made on other galaxies, and had nothing to do with knowing how fast our solar system traveled around our own galaxy.  You can measure how fast an object like a star is moving relative to us by looking at the Doppler shift of its light.  If we look at a distant rotating spiral galaxy nearly edge on,  stars on one side will be coming towards us relative to that galaxy's center, and the one on the other side will be moving away. 

Now the galaxy as a whole my be moving towards or away from us, and some of that may be due to out own solar system's orbit in our galaxy, but that doesn't matter.  Because that factor is going to added or subtracted equally from all the star velocities we are measuring.  Thus all we need to note in the difference we measure in the velocities to work out how fast they are orbiting their galaxy.  And by looking at stars at varying distances from the galaxy's center we can plot a rotation curve. And when we look at these plotted curves, we find they don't look like they should for the amount and distribution of matter we see for the galaxy in question.  Something else is supplying a gravitational effect besides what we can see.  Not only that, but there has to be a lot more of that something than what we see, and it can't be distributed the same way as what we see.   If it were made of normal matter, even if it were cold gas or dust, it still would give us some visual clue. That part of it located between us and the galaxy would absorb some of the light of the galaxy,( and not evenly for all frequencies of light), and no matter how cold it was, it would radiate, even if only at radio frequencies. 

The conclusion is, that whatever is is, it doesn't react with light or any electromagnetic frequency at all,  but still interacts via gravity, thus Dark matter.

Another observation involve how gravity bends light.  By looking at light from further objects as it passes near to the galaxy we can see how the gravity of the galaxy acts like a lens, bending the light around it.  And like we can determine the curve of a glass lens from the way it bends light, we can determine how the mass of the galaxy is distributed by looking at how light passing near it bend.   This gravitational lensing gives the same result for mass distribution as the rotation curves give.  So two independent observations confirm the same thing.

It is clear that you have not done any real study of of these subjects, and are basing your conclusions on a number of misconceptions.

 

*And despite you claim, we can do versions of these experiments.  While this wasn't possible at the time Einstein formed them to do many of them, since then we have gained the ability to measure time much more accurately, and accelerate at least subatomic particles up to near light speed. There was one experiment/observation that was within the capabilities of the time, and that was measuring the bending of light by gravity.  Though this did have to wait for a solar eclipse for the right conditions.  It was the verification of this observation during an eclipse that was the first step towards the acceptance of Relativity.

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19 hours ago, Drakes said:

Isn't everything in motion?  The Earth spins on it's axis, the Earth spins round the sun, the Sun spins round the galactic core and the galaxy itself is in motion set by the big bang, it is not known if the universe itself may be moving or vibrating as well.  So to be stationary one would need to understand all frames of motion exactly and counteract each one exactly and since galactic motion can only be estimated stationary from a human perspective is just not possible

Picture yourself on a rock in empty space - you can see nothing until you see me sitting on a rock coming towards you. In my frame you are moving and I'm motionless. Who is correct?

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Posted (edited)
1 hour ago, StringJunky said:

Picture yourself on a rock in empty space - you can see nothing until you see me sitting on a rock coming towards you. In my frame you are moving and I'm motionless. Who is correct?

In one plane alone we are currently moving 1.3 million miles per hour that is the linear galactic movement plane, the Milky Way is headed toward LEO, so if an Apollo type spacecraft is launched toward Leo it's true speed is 1,325,000 miles per hour if launched directly away from LEO it's true speed drops to 1,275,000 miles per hour but the distance traveled is in the opposite direction of the observed movement since the entire galaxy is moving in the opposite direction at 1,300,000 miles per hour at launch. So what is observed is just not what it seems to be, if the spacecraft were to attain a speed of 1,300,000 miles per hour away from LEO it would become still in one plane and the galaxy would appear to move around the spacecraft. So still in any way is just not possible.   The above also ignores the 490,000 miles per hour orbital speed that we are simultaneously spinning around the galactic core.

I also know that in the early 1900's that a train was a lot more amazing than it is today, but someone imagining train tracks into space might actually have been exhibiting a grandiose lack of imagination.

Edited by Drakes

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37 minutes ago, Drakes said:

In one plane alone we are currently moving 1.3 million miles per hour that is the linear galactic movement plane, the Milky Way is headed toward LEO, so if an Apollo type spacecraft is launched toward Leo it's true speed is 1,325,000 miles per hour if launched directly away from LEO it's true speed drops to 1,275,000 miles per hour but the distance traveled is in the opposite direction of the observed movement since the entire galaxy is moving in the opposite direction at 1,300,000 miles per hour at launch. So what is observed is just not what it seems to be, if the spacecraft were to attain a speed of 1,300,000 miles per hour away from LEO it would become still in one plane and the galaxy would appear to move around the spacecraft. So still in any way is just not possible.   The above also ignores the 490,000 miles per hour orbital speed that we are simultaneously spinning around the galactic core.

I also know that in the early 1900's that a train was a lot more amazing than it is today, but someone imagining train tracks into space might actually have been exhibiting a grandiose lack of imagination.

What is it going to take to get this into your head? There is no such thing as "true" speed. That term has no meaning in our universe.

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Just now, Janus said:

What is it going to take to get this into your head? There is no such thing as "true" speed. That term has no meaning in our universe.

There is also no way to be still which is what I said originally. 

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Expanding on String Junky's example...

Picture yourself alone ( in a spacesuit ) in empty space with no other features.
ccan you tell if you are linearly moving at 10 km/hr ?
Can you tell if you are moving at 1000 km/hr ?
How about at 100 000 km/hr ?
NO !  You would have no 'feeling' of speed, no sensation that there was any difference from you being at rest.
And there is no experiment you can do to determine your speed.
That is an inertial frame; and they have been known about at least since Galileo ( never mind Einstein )

Now picture yourself sgain in the same situation but you accelerate from one seed to another.
Even though you have nothing as a reference to measure your speed against, you immediately know that it is changing because you are pushed back into your spacesuit.
And the simplest experiment, like dropping an object, will see it left behind.
You know that you are moving in many ways.
That is a non-inertial frame.

To re-cap, in a non-inertial frame you can always tell if you are moving.
In an inertial frame you cannot; in an empty space, you might as well be at rest no matter what your speed, and the only way to tell if you are moving is 'relative' to another object, which is probably itself moving. That means all our experiments and derived laws of Physics apply to these inertial frames where we actually have no idea what the 'true' speed is, as there is NO 'true' speed.

This is what Swansont told you at the beginning of this thread; you would have been further ahead asking questions about what you don't understand, instead of blindly insisting 'everything is in motion'  ( irrelevant dead-end argument ).

Any questions ???

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1 hour ago, Drakes said:

In one plane alone we are currently moving 1.3 million miles per hour that is the linear galactic movement plane, the Milky Way is headed toward LEO

So that’s our speed relative to Leo. But one can just as validly say Leo is moving toward us. There is no difference in the physics 

 

11 minutes ago, Drakes said:

There is also no way to be still which is what I said originally. 

Which has no practical effect on the topic.

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13 minutes ago, Drakes said:

There is also no way to be still which is what I said originally. 

Which has already been agreed.

but consider this question from another more mundane point of view.

The pistons in my car are moving up and down, the cams are going round and round and the followers are oscillating etc etc.

So, rather like your universe, everything is moving round and about everything else.

The motion of the pistons, compared to that of the cam followers is different from the motion of the pistons compared to the prop shaft etc etc.

They are all in relative motion vis a vis each other and each comparison is different.

But there is a further situation overlaid on this.

These relationships depend upon the throttle setting, not the motion of the vehicle.
They will be the same whether my car is standing 'still' on my driveway or moving down the motorway at 60 mph.

All of these motions are compared (ie relative) to the chassis of the car.

And even if that chassis is still on the driveway the driveway itself is moving round with the rotation of  the surface of the Earth at around 650 mph.
But we don't normally consider that.

Underlying this build up is the fact that there is no absolute rest frame in the universe.

We just pick one and in Relativity it is normally called The Laboratory Frame.

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4 minutes ago, MigL said:

Expanding on String Junky's example...

Picture yourself alone ( in a spacesuit ) in empty space with no other features.
ccan you tell if you are linearly moving at 10 km/hr ?
Can you tell if you are moving at 1000 km/hr ?
How about at 100 000 km/hr ?
NO !  You would have no 'feeling' of speed, no sensation that there was any difference from you being at rest.
And there is no experiment you can do to determine your speed.
That is an inertial frame; and they have been known about at least since Galileo ( never mind Einstein )

Now picture yourself sgain in the same situation but you accelerate from one seed to another.
Even though you have nothing as a reference to measure your speed against, you immediately know that it is changing because you are pushed back into your spacesuit.
And the simplest experiment, like dropping an object, will see it left behind.
You know that you are moving in many ways.
That is a non-inertial frame.

To re-cap, in a non-inertial frame you can always tell if you are moving.
In an inertial frame you cannot; in an empty space, you might as well be at rest no matter what your speed, and the only way to tell if you are moving is 'relative' to another object, which is probably itself moving. That means all our experiments and derived laws of Physics apply to these inertial frames where we actually have no idea what the 'true' speed is, as there is NO 'true' speed.

This is what Swansont told you at the beginning of this thread; you would have been further ahead asking questions about what you don't understand, instead of blindly insisting 'everything is in motion'  ( irrelevant dead-end argument ).

Any questions ???

You can live your entire life imagining and never get anywhere, in fact lots of people do this quite well.  Imagine what Einstein could really have achieved if he ever put his pencil down got out of his chair and did a real experiment like Von Braun instead of just imagining.  At one time the Earth was flat because one could clearly see the edge where the ocean fell off, it took men with logs and sails to eventually never reach the edge and the spherical Earth was discovered.  You can only go so far with a pencil then you have get up and test ones findings.  Einstein is not and never was a God, his math told him that the Universe was not expanding, perhaps that math was right and Hubble's is wrong.

 

We all want to know, however none of us does, in fact we know exactly the same as to what we are as the first Neanderthal did.  Sad but true.  The speeds I mentioned were not imagined they were calculated.

 

What is the imaginary power source for your imaginary space suit to keep you from freezing solid?  

3 minutes ago, studiot said:

Which has already been agreed.

but consider this question from another more mundane point of view.

The pistons in my car are moving up and down, the cams are going round and round and the followers are oscillating etc etc.

So, rather like your universe, everything is moving round and about everything else.

The motion of the pistons, compared to that of the cam followers is different from the motion of the pistons compared to the prop shaft etc etc.

They are all in relative motion vis a vis each other and each comparison is different.

But there is a further situation overlaid on this.

These relationships depend upon the throttle setting, not the motion of the vehicle.
They will be the same whether my car is standing 'still' on my driveway or moving down the motorway at 60 mph.

All of these motions are compared (ie relative) to the chassis of the car.

And even if that chassis is still on the driveway the driveway itself is moving round with the rotation of  the surface of the Earth at around 650 mph.
But we don't normally consider that.

Underlying this build up is the fact that there is no absolute rest frame in the universe.

We just pick one and in Relativity it is normally called The Laboratory Frame.

WE also do not typically when thinking logically of piston movement lay train tracks into space.  Screw the fucking thought experiment unless the thought is how to actually get there.  If you wanna keep rehashing cats in a box go ahead, my thoughts go in one direction forward

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