Absolute stationary

[Spyman]

The rest points of the CMB frame arguably represent a prefferred "volume" but how can you claim they are at absolute rest?

 

The rest points of the CMB frame are only at rest wrt each other locally.

 

They represent an inertial frame locally but are moving with respect to each other at greater velocity with distance apart.

First: I did not mean separete points of the CMB, didn't You realize that ?

 

What happens when You take the sum of all points, the total of CMB ?

 

 

Secondly: I don't claim anything here, I gave Scribble my interpretation of the Big Bang theory and the CMB.

(Which swansont immediately claimed wrong, without a good explanation.)

 

I thought words like "(The predicted, (by me), results of Your experiments.)" represents more a personal conclusion than a proved science fact.

 

 

Edit: And why are You quoting my post to swansont instead of the post You argue against ?

[Guest spiralx]

Isn't the total gravitational field at the center of the universe necessarily zero? Maybe he could distinguish it that way.

There isn't a centre of the universe though.

[J.C.MacSwell]

First: I did not mean separete points of the CMB' date=' didn't You realize that ?

[b']

What happens when You take the sum of all points, the total of CMB ?[/b]

Secondly: I don't claim anything here, I gave Scribble my interpretation of the Big Bang theory and the CMB.

(Which swansont immediately claimed wrong, without a good explanation.)

 

I thought words like "(The predicted, (by me), results of Your experiments.)" represents more a personal conclusion than a proved science fact.

 

Does such a point exist? I'm questioning your perspective, not your ideas which I think are interesting.

[swansont]

swansont' date=' You know what I mean, "pecking" on my English is not helping...

[/quote']

 

I wasn't. (and unless there's a really funny aspect to it, I don't draw attention to such things)

 

I honestly don't know what you meant by that phrase. My comment was meant to mean that I needed clarification.

 

If you mean that the rest frame of the CMB means you are at rest with respect to the expansion, OK. But what physics measurements are preferred in that frame as opposed to another inertial frame?

[Zeth]

What you are describing seems to be the aether. By the early 20th century attempts to detect the aether (or, more specifically, attempts to detect the planet's movement through the aether) had called the concept into doubt. It was formally dispensed of by the work of Albert Einstein of general relativity which held that there was no one stationary point in the universe from which everything was moving away.

[Spyman]

I wasn't. (and unless there's a really funny aspect to it' date=' I don't draw attention to such things)

 

I honestly don't know what you meant by that phrase. My comment was meant to mean that I needed clarification.[/quote']OK, communication is difficult between different languages but can be harder between different levels of knowledge. I cant reach up to Your level so You will need to try to reach down to mine and others.

 

If you mean that the rest frame of the CMB means you are at rest with respect to the expansion, OK. But what physics measurements are preferred in that frame as opposed to another inertial frame?

I thought I agreed with You that there are no differences between that frame an others, in my post #17.

 

To clearify: "There's no preferred result you get in that coordinate system". With Your own words.

[Spyman]

Does such a point exist? I'm questioning your perspective, not your ideas which I think are interesting.

Again, I am not discussing points here.

 

If BB and CMB is uniform on a large scale, how will an alien civilization 10 billions lightyears away see CMB ?

 

If we and they both launch a spacemission where the spaceships will accelerate to a standstill relative their local CMB, will they be at rest relative each other ? I belive that.

 

The universe is expanding so they will disperse from each other several times faster than light, is that what You meant ?

 

But the streaching of space is not a speed through space as I understand it. If it is then is FTL possible ?

 

Where is the difference between our's perspective ?

 

though we would expect a null result due to the second [b']if[/b]

The second if, the "null result", is the part I am interested in. Can You explain why ?

 

If speed is only relative the observer then why a speedlimit relative space, (through space) ?

 

More clearly: Can space itself, the vacuum, be considered as an observer ?

[Johnny5]

The CMB frame may be a rest frame. That doesn't make it the rest frame.

 

You can always see if you are moving or at rest' date=' with respect to something. What abolute rest means is that you can say for sure that you, or the other object, is the one that is at rest.[/quote']

 

Dr. Swanson

 

Just to be clear, if there is such a thing as a frame which is at absolute rest, then motion isn't relative?

 

What could make one rest frame special above another?

[Severian]

By the early 20th century attempts to detect the aether (or, more specifically, attempts to detect the planet's movement through the aether) had called the concept into doubt.

 

I always find that slightly ironic. If their experiments had been better at the time, they could have detected the Earth's movement with respect to the CMBR, which would have confused things horribly. They basically came to the right conclusion by having the wrong experiment.

[J.C.MacSwell]

Again' date=' I am not discussing points here.

 

If BB and CMB is uniform on a large scale, how will an alien civilization 10 billions lightyears away see CMB ?

 

If we and they both launch a spacemission where the spaceships will accelerate to a standstill relative their local CMB, [b']will they be at rest relative each other [/b] ? I belive that.

 

The universe is expanding so they will disperse from each other several times faster than light, is that what You meant ?

 

But the streaching of space is not a speed through space as I understand it. If it is then is FTL possible ?

 

Where is the difference between our's perspective ?

 

The second if, the "null result", is the part I am interested in. Can You explain why ?

 

If speed is only relative the observer then why a speedlimit relative space, (through space) ?

 

More clearly: Can space itself, the vacuum, be considered as an observer ?

 

I think you can claim mathematically that they are (at rest wrt each other), although some laws of physics may require corrections/adjustments to allow for your frame/perspective.(which I think is a very useful frame for cosmology)

 

To claim that they are also "absolutely" at rest is a bit of a "stretch" if you will excuse the pun.

 

I think the experiment, which requires instant transmission of results and therefore is excluded as a possibility in SRT, would be expected to produce a null result in that no rest point on any inertial frame would be expected to have a faster clock than any other.

[Spyman]

I think you can claim mathematically that they are (at rest wrt each other)' date=' although some laws of physics may require corrections/adjustments to allow for your frame/perspective.(which I think is a very useful frame for cosmology)

 

To claim that they are also "absolutely" at rest is a bit of a "stretch" if you will excuse the pun.[/quote']OK, so we view the expansion of the Universe different then.

 

I think the experiment, which requires instant transmission of results and therefore is excluded as a possibility in SRT, would be expected to produce a null result in that no rest point on any inertial frame would be expected to have a faster clock than any other.

I think Severian's explanation in this post is good:

 

A small question http://www.scienceforums.net/forums/showthread.php?p=170813#post170813

 

It's almost the same thing, when the spaceships passes the second time they can do it so close that the transmission time would be very short. The instant transmission due to entanglement will not make any difference.

 

I think the same rules will apply for the spaceprobes, they will all show the same differences in time relative the spaceship sending them out in the spaceships frame. But will have different times relative each other in their own frames.

[Scribble]

It's almost the same thing' date=' when the spaceships passes the second time they can do it so close that the transmission time would be very short. The instant transmission due to entanglement will not make any difference.

 

I think the same rules will apply for the spaceprobes, they will all show the same differences in time relative the spaceship sending them out in the spaceships frame. But will have different times relative each other in their own frames.[/quote']

 

I don't agree. The point of the experiment was to find the 'direction' (relative to the expanding universe) that is stationary.

If you send it in a circle I don't see how you can determine the direction.

Wouldn't it be the same reason that you can't speed up, travel, slow down again and get measurements as they would be distorted due to the acceleration (hence using entanglement).

 

The point of using time dilation was to find a linear variable that could be measured and compaired between frames that was affected by the velocity of the probe. If there is another form of measurement that would work that's fine

 

I'm quite open to been wrong or corrected, but I feel like my idea still has some credit.

[Spyman]

The point of the experiment was to find the 'direction' (relative to the expanding universe) that is stationary.

The 'direction' relative the expanding universe, at absoulute rest relative the center of Universe ?

 

AFAIK The Universe is expanding uniformly in all 3D directions so the probes will yield the same results.

 

If the results would show that the expansion is not uniform it would tell us a lot about the shape of Universe and show the direction towards the center.

 

If you send it in a circle I don't see how you can determine the direction.

If You are able to go around the Universe travelling in a straight line, it would also tell You a lot about the shape of Universe. But that was not the point, more about this below.

 

Wouldn't it be the same reason that you can't speed up, travel, slow down again and get measurements as they would be distorted due to the acceleration (hence using entanglement).

I might be missing something again but wouldn't the entanglement only let You get the information faster ?

 

The clocks measuring time inside the spaceprobes would still show different times due to acceleration, gravity anomalys and speed.

 

If we remove the acceleration by syncronization over the entanglement, which is done without it in "A small question", and for the analogys sake pretend there is no gravity anomaly, then the probes would shove different times if the expansion is different in different directions. If the expansion is uniform then the probes would shove the same time dilation relative the center spaceship.

 

The point of using time dilation was to find a linear variable that could be measured and compaired between frames that was affected by the velocity of the probe.

And if all probes have the same speed relative the center spaceship they will all shove the same time.

 

If there is another form of measurement that would work that's fine

That would depend on the shape of the universe and if the expansion is uniform or not.

 

I was on Your line for a time but that was because I didn't understand this part of relativity well enough but Severians post in that thread somehow enlighted me.

(Not that I understand relativity completely now but I have made some progress.)

 

If I got it right then it's not the speed through the vacuum that cause the time dilation it's the speed relative the observers. Time dilation is not a mechanism caused by space when passing through. When You change between the frames You change in time also.

 

Entanglement, if possible, will not let You be in both frames at the same time, You can't be both young and old, it will only let You communicate faster. The clocks in the probes will still be stuck in their frames.

 

That thread is much about the same thing but uses the concept of a hypersphere instead of entanglement.