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Author Topic:   What is "the fabric" of space-time?
onifre
Member (Idle past 3037 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 286 of 327 (473584)
06-30-2008 11:32 PM
Reply to: Message 283 by lyx2no
06-30-2008 6:01 PM


Re: Very ?????
I'm uncertain as to what you mean by this, but it seems you may be reading too much into a mechanical analogy. Can you expound upon it?
I may very well be reading too much into it, it just seemed similar in comparison to the rubber band analogy that CS gave me. He pointed to each point of the rubber band expanding equally, I was comparing that to the numbers increasing equally as well.
Did that make sense?

All great truths begin as blasphemies
I smoke pot. If this bothers anyone, I suggest you look around at the world in which we live and shut your mouth.

This message is a reply to:
 Message 283 by lyx2no, posted 06-30-2008 6:01 PM lyx2no has replied

Replies to this message:
 Message 287 by lyx2no, posted 07-01-2008 12:17 AM onifre has replied

  
lyx2no
Member (Idle past 4802 days)
Posts: 1277
From: A vast, undifferentiated plane.
Joined: 02-28-2008


Message 287 of 327 (473586)
07-01-2008 12:17 AM
Reply to: Message 286 by onifre
06-30-2008 11:32 PM


Re: Very ?????
The important points to get from this analogy are, "Why would objects farther away have proportionally greater red shift?" and,"Why do all locations seem locally to be the center?"
I use the same analogy frequently; however, I generally use a spring because springs have a built in unit, the coil. If one doubles the length of the spring, one doubles the length of each individual coil regardless of where in the spring it is located. The more coils two markers were separated by the more millimeters added to their separation after one second. Every coil sees all other coils moving away from themselves, and all see it in the exact same way.
If one starts with a one-thousand coil, one meter long spring and doubles its length in one second, a coil has increased its length by one millimeter in one second, Or, stated in a like form to Hubble's constant, 1 (mm/sec)/coil*.
AbE: *This is tens of quadrillions of times faster than Hubble's constant {71 (km/sec)/Mps}. Note, however, that because the coil changes size whereas the megaparsec is a constant this analogy quickly fails.
Edited by lyx2no, : Got ahead of myself.
Edited by lyx2no, : Add info.
Edited by lyx2no, : No reason given.

Kindly
Everyone deserves a neatly dug grave. It is the timing that's in dispute.

This message is a reply to:
 Message 286 by onifre, posted 06-30-2008 11:32 PM onifre has replied

Replies to this message:
 Message 288 by onifre, posted 07-01-2008 8:24 AM lyx2no has replied

  
onifre
Member (Idle past 3037 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 288 of 327 (473607)
07-01-2008 8:24 AM
Reply to: Message 287 by lyx2no
07-01-2008 12:17 AM


Re: Very ?????
The important points to get from this analogy are, "Why would objects farther away have proportionally greater red shift?" and,"Why do all locations seem locally to be the center?"
Question 1: The greater red-shifts are due to the curvature of spacetime, correct?
Question 2: Thats just the illusion that we are the center, from any other galaxies observational reference it would seem like they are the center, correct?
I use the same analogy frequently; however, I generally use a spring because springs have a built in unit, the coil. If one doubles the length of the spring, one doubles the length of each individual coil regardless of where in the spring it is located. The more coils two markers were separated by the more millimeters added to their separation after one second. Every coil sees all other coils moving away from themselves, and all see it in the exact same way
Yes this analogy, and the rubber band analogy, are both very simple to understand. The numbers analogy was just something that I connected with the rubber band analogy, it isn't actually the same.
It was an infinity question that we were asked, its a simple question but it can throw you off initially. Basically the question was 'whats the greater set of numbers 1,2,3,4,5,6,7 etc... or 2,4,6,8,10,12 etc... Its obviously simple that if both go to infinity then both are equal, neither number is larger.
But when you write them above each other say,
1,2,3,4,5,6,7,8,9....
2,4,6,8,10,12,14,16....
4,8,12,16,20,24,28,32...
Its all still the same however, they seem larger when you first look at it. This, to me, made a connection conceptually with the rubber band analogy, and now to your coil analogy.
Thanks for your analogy too, its been much help as well.

All great truths begin as blasphemies
I smoke pot. If this bothers anyone, I suggest you look around at the world in which we live and shut your mouth.

This message is a reply to:
 Message 287 by lyx2no, posted 07-01-2008 12:17 AM lyx2no has replied

Replies to this message:
 Message 290 by lyx2no, posted 07-01-2008 7:06 PM onifre has replied

  
Son Goku
Inactive Member


Message 289 of 327 (473658)
07-01-2008 4:33 PM
Reply to: Message 274 by cavediver
06-29-2008 1:13 PM


Re: It's a sad day...
Apologies for off-topicness.
What with this reply SG just submitted, and his recent reply to randman, it seems that SG's keen resolve and determined patience are starting to show the very first signs of cracks. Reminds me of someone else, much further along the road to complete dispair
Ah, don't worry. The standard of this forum (in any area of discussion) is far too high for that to happen. Compare with another forum where I was recently accused of being a "dogmatic and textbook thumping member of the orthodoxy" for my "claim" that Neanderthals didn't land on the moon.

This message is a reply to:
 Message 274 by cavediver, posted 06-29-2008 1:13 PM cavediver has not replied

  
lyx2no
Member (Idle past 4802 days)
Posts: 1277
From: A vast, undifferentiated plane.
Joined: 02-28-2008


Message 290 of 327 (473674)
07-01-2008 7:06 PM
Reply to: Message 288 by onifre
07-01-2008 8:24 AM


Re: Very ?????
Question 1: The greater red-shifts are due to the curvature of spacetime, correct?
The cosmological red shift is caused by the expansion of the space between the signals source and the observer.
A photon originating half again as far as Andromeda (1 Mps) takes, in our reference frame, 3.26 million years to get here. In that 3.26 million years the source has moved away at 71 kilometers per second. The initial proper distance is 775 lys less then the final proper distance.
Now, we are measuring this photon at two different times. The first time is measured by inference, where we would expect it to be in the spectra, say the 526.96 nm emission line of neutral Fe, and the second time by measuring its current position in the spectra.
Remember, also, that according to the photon no time or space was crossed. It had a certain energy, and therefore wavelength, upon emission; and hence, bounced up and down only so many times in its frame and in ours.
The photon's departure wavelength was measured as # bounces/3.26”1022 meters, while the photon's arrival wavelength is measured as # bounces/(3.26”1022 + 7.31”1018) meters. The emission wavelength of the photon will appear stretched that extra bit (1 part in 4000), and its spectral position will shift that far to the red.
Question 2: Thats just the illusion that we are the center, from any other galaxies observational reference it would seem like they are the center, correct?
It is more delusion than illusion, caused by conceit.

Kindly
Everyone deserves a neatly dug grave. It is the timing that's in dispute.

This message is a reply to:
 Message 288 by onifre, posted 07-01-2008 8:24 AM onifre has replied

Replies to this message:
 Message 291 by onifre, posted 07-02-2008 12:15 PM lyx2no has replied
 Message 292 by BMG, posted 07-02-2008 12:54 PM lyx2no has replied

  
onifre
Member (Idle past 3037 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 291 of 327 (473724)
07-02-2008 12:15 PM
Reply to: Message 290 by lyx2no
07-01-2008 7:06 PM


Re: Very ?????
Remember, also, that according to the photon no time or space was crossed. It had a certain energy, and therefore wavelength, upon emission; and hence, bounced up and down only so many times in its frame and in ours.
Could you explain a bit more on this?
Not the part about the photons POV, but the bouncing up and down, im just now starting to understand quantum...a tiny bit
Is it the bouncing that creates the energy and therefore the wavelength?
Assuming thats correct, is it then the space thats expanding between the galaxies that stretches the wavelength causing the red-shift?
You wrote...
quote:
The cosmological red shift is caused by the expansion of the space between the signals source and the observer.
...I think this is the answer to what I just asked, but I just want to make sure that i've understood you properly.
It is more delusion than illusion, caused by conceit.
I would say its more a lack of understanding coupled with no desire to understand. The ego-centric human brain takes it from there.

All great truths begin as blasphemies
I smoke pot. If this bothers anyone, I suggest you look around at the world in which we live and shut your mouth.

This message is a reply to:
 Message 290 by lyx2no, posted 07-01-2008 7:06 PM lyx2no has replied

Replies to this message:
 Message 293 by lyx2no, posted 07-02-2008 1:16 PM onifre has replied

  
BMG
Member (Idle past 295 days)
Posts: 357
From: Southwestern U.S.
Joined: 03-16-2006


Message 292 of 327 (473727)
07-02-2008 12:54 PM
Reply to: Message 290 by lyx2no
07-01-2008 7:06 PM


Re: Very ?????
Hi lyx2no.
Remember, also, that according to the photon no time or space was crossed.
Sorry to interrupt but I have a question. And, also, I am far less knowledgable than everyone else on this topic, but I am still interested in the discussion, and will try to limit it to this one question: are you saying that from the photon's frame of reference no time or space was crossed? Does my frame of reference from earth change anything?
I can't wrap my head around this. How can something that travels through space at c not be traveling through space?

This message is a reply to:
 Message 290 by lyx2no, posted 07-01-2008 7:06 PM lyx2no has replied

Replies to this message:
 Message 294 by lyx2no, posted 07-02-2008 3:43 PM BMG has replied
 Message 295 by onifre, posted 07-02-2008 4:05 PM BMG has replied

  
lyx2no
Member (Idle past 4802 days)
Posts: 1277
From: A vast, undifferentiated plane.
Joined: 02-28-2008


Message 293 of 327 (473729)
07-02-2008 1:16 PM
Reply to: Message 291 by onifre
07-02-2008 12:15 PM


Re: Very ?????
Is it the bouncing that creates the energy and therefore the wavelength?
Sorry 'bout that, the bouncing up and down is my glibness shining through. Many folks imagine a light wave being an actual particle (pseudo-photon) moving up and down as if it were on a sinusoidal roller coaster. It has much more to do with cartoon mechanics than QM. The wavelength of the wave form of a particle is dependent upon its energy.
I think this is the answer to what I just asked, but I just want to make sure that i've understood you properly.
You have. Sorry again, got to run.
AbE: It can, in a sense, be viewed as caused by space curvature, but it's a hard row to hoe.
Edited by lyx2no, : Returned.

Kindly
Everyone deserves a neatly dug grave. It is the timing that's in dispute.

This message is a reply to:
 Message 291 by onifre, posted 07-02-2008 12:15 PM onifre has replied

Replies to this message:
 Message 296 by onifre, posted 07-02-2008 4:07 PM lyx2no has not replied

  
lyx2no
Member (Idle past 4802 days)
Posts: 1277
From: A vast, undifferentiated plane.
Joined: 02-28-2008


Message 294 of 327 (473743)
07-02-2008 3:43 PM
Reply to: Message 292 by BMG
07-02-2008 12:54 PM


Re: Very ?????
I can't wrap my head around this. How can something that travels through space at c not be traveling through space?
The lorentz contraction of space is given by, L = Lo (1 - v2/c2). Look what happens when velocity approaches the speed of light, v -” c. (v/c)2 = (c/c)2 = 12 = 1; (1 - 1) = 0; And, 0 ” Lo = 0 = L. Length is reduced to zero. How long would it take to go zero distance?

Kindly
Everyone deserves a neatly dug grave. It is the timing that's in dispute.

This message is a reply to:
 Message 292 by BMG, posted 07-02-2008 12:54 PM BMG has replied

Replies to this message:
 Message 297 by BMG, posted 07-03-2008 5:01 AM lyx2no has replied

  
onifre
Member (Idle past 3037 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 295 of 327 (473746)
07-02-2008 4:05 PM
Reply to: Message 292 by BMG
07-02-2008 12:54 PM


Re: Very ?????
Sorry to interrupt but I have a question.
By all means...
Does my frame of reference from earth change anything?
Yes in the sense that you are the observer of the photons' travel.
How can something that travels through space at c not be traveling through space?
The key word is 'relative'. Relative to the photon we are moving towards it.
Example: You leave Earth traveling at .99% the SoL. Ignoring the acceleration factor which would indicate to YOU that you're the one moving, the Earth in your frame of reference would seem like the one traveling at .99% the SoL away from you.
IOW, To you in the rocket, you are stationary and the Earth is pulling away from you.
An easier example would be you in a car traveling towards a wall. To you the wall is coming at you, to the wall you are coming at it. Again, ignoring accelaration.
Its all in the frame of reference of the observer.
Heres a great beginner lecture from Berkley,
https://www.youtube.com/watch?v=7Kdq_1bcAYs
Hope that helped.

All great truths begin as blasphemies
I smoke pot. If this bothers anyone, I suggest you look around at the world in which we live and shut your mouth.

This message is a reply to:
 Message 292 by BMG, posted 07-02-2008 12:54 PM BMG has replied

Replies to this message:
 Message 298 by BMG, posted 07-03-2008 6:16 AM onifre has replied

  
onifre
Member (Idle past 3037 days)
Posts: 4854
From: Dark Side of the Moon
Joined: 02-20-2008


Message 296 of 327 (473747)
07-02-2008 4:07 PM
Reply to: Message 293 by lyx2no
07-02-2008 1:16 PM


Re: Very ?????
You have. Sorry again, got to run.
Thanks again lyx2no...

All great truths begin as blasphemies
I smoke pot. If this bothers anyone, I suggest you look around at the world in which we live and shut your mouth.

This message is a reply to:
 Message 293 by lyx2no, posted 07-02-2008 1:16 PM lyx2no has not replied

  
BMG
Member (Idle past 295 days)
Posts: 357
From: Southwestern U.S.
Joined: 03-16-2006


Message 297 of 327 (473826)
07-03-2008 5:01 AM
Reply to: Message 294 by lyx2no
07-02-2008 3:43 PM


Re: Very ?????
The lorentz contraction of space is given by, L = Lo (1 - v2/c2). Look what happens when velocity approaches the speed of light, v -” c. (v/c)2 = (c/c)2 = 12 = 1; (1 - 1) = 0; And, 0 ” Lo = 0 = L. Length is reduced to zero. How long would it take to go zero distance?
So, Lorentz Contraction suggests that an object that is moving relative to a stationary observer is actually contracting, but from the frame of reference of the moving object it appears unchanged?
abE: Let me clarify this, if I can, and please correct me if I'm wrong: two objects, one that is moving and one that is stationary, experience time differently. The moving object experiences less time than the stationary object, and the amount is based upon the Lorentz Contraction formula?
Edited by Infixion, : Clarification

This message is a reply to:
 Message 294 by lyx2no, posted 07-02-2008 3:43 PM lyx2no has replied

Replies to this message:
 Message 299 by lyx2no, posted 07-03-2008 8:32 AM BMG has replied

  
BMG
Member (Idle past 295 days)
Posts: 357
From: Southwestern U.S.
Joined: 03-16-2006


Message 298 of 327 (473828)
07-03-2008 6:16 AM
Reply to: Message 295 by onifre
07-02-2008 4:05 PM


Re: Very ?????
Thank you, onifre, for the video.
The key word is 'relative'. Relative to the photon we are moving towards it.
One fact I absorbed from the vid is that, essentially, all motion is relative to the frame of reference of the observer, but the acceleration is constant.
Regarding the twin paradox, the twin that leaves earth at .99% the SOL and travels for six months only to make a return trip of six months will have aged roughly one year, while the twin left on the earth will have aged roughly 7.1 years? And the only evidence that the twin leaving earth was actually moving was the acceleration they experienced? Otherwise, there would have been no way of knowing which one was moving and which wasn't?

This message is a reply to:
 Message 295 by onifre, posted 07-02-2008 4:05 PM onifre has replied

Replies to this message:
 Message 300 by New Cat's Eye, posted 07-03-2008 9:19 AM BMG has replied
 Message 304 by onifre, posted 07-03-2008 8:31 PM BMG has not replied

  
lyx2no
Member (Idle past 4802 days)
Posts: 1277
From: A vast, undifferentiated plane.
Joined: 02-28-2008


Message 299 of 327 (473834)
07-03-2008 8:32 AM
Reply to: Message 297 by BMG
07-03-2008 5:01 AM


Re: Very ?????
. and the amount is based upon the Lorentz Contraction formula?
The amount is based on the behavior of the Universe and we can calculate it with the Lorentz's formula , but yes.
P.S. I'd not generally correct that bit, but I've had to put up with a few folks of late who can't grasp that the math isn't a magic formula used by atheists to change the Universe more to their own liking. And they are reading . seeking the magic symbols that will allow them to change it back.
Edited by lyx2no, : Add P.S.
Edited by lyx2no, : Grammar.

Kindly
Everyone deserves a neatly dug grave. It is the timing that's in dispute.

This message is a reply to:
 Message 297 by BMG, posted 07-03-2008 5:01 AM BMG has replied

Replies to this message:
 Message 301 by BMG, posted 07-03-2008 11:28 AM lyx2no has not replied

  
New Cat's Eye
Inactive Member


Message 300 of 327 (473841)
07-03-2008 9:19 AM
Reply to: Message 298 by BMG
07-03-2008 6:16 AM


Re: Very ?????
And the only evidence that the twin leaving earth was actually moving was the acceleration they experienced? Otherwise, there would have been no way of knowing which one was moving and which wasn't?
Right.
I've seen arguments against the twin paradox that go something like: according to relativity, its all based on your frame of reference. So, to the twin on the spaceship, the earth is moving away at 99% SoL and the twin on earth should be the one that is younger, not the one on the spaceship. But we know that the spaceship is the one moving because it is the one that is experiencing the acceleration.

This message is a reply to:
 Message 298 by BMG, posted 07-03-2008 6:16 AM BMG has replied

Replies to this message:
 Message 302 by BMG, posted 07-03-2008 11:31 AM New Cat's Eye has replied

  
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