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Author Topic:   General Relativity.
crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 91 of 129 (252343)
10-17-2005 7:58 AM
Reply to: Message 90 by simple
10-16-2005 11:57 PM


Re: Light and Energy
Those with imperfect knowledge should stick to what they know, and not get to preaching alternate creation.
"Alternate creation"? As far as I'm concerned, pal, you're the one with the alternate creation fable.

This message is a reply to:
 Message 90 by simple, posted 10-16-2005 11:57 PM simple has replied

Replies to this message:
 Message 93 by simple, posted 10-17-2005 10:47 PM crashfrog has not replied

  
sidelined
Member (Idle past 5908 days)
Posts: 3435
From: Edmonton Alberta Canada
Joined: 08-30-2003


Message 92 of 129 (252361)
10-17-2005 9:29 AM
Reply to: Message 88 by simple
10-16-2005 10:32 PM


Re: Light and Energy
14gipper
If there was a whole lot more than the physical universe, and we hardly have a grip on what's going on here, that would be comparitively clueless.
Why do you always reference to something other than the physical universe as though that had any meaning? What does you mean by not physical my friend?
If not, and the unknowns that abound are really just around the corner, if we follow the carrot on the stick, then, it is true, we have some good clues now, after all. But which of these best applies, we really don't know, and indeed, in that respect are clueless indeed.
Science operates in the region between known and unknown and has found physical explanations for all the questions of how the world operates when we can properly use experiments to test the models from which we learn. That we have different possible scenarios for further study of leading edge physics is not as result of being clueless but because of the difficulty of producing the conditions necessary to test the modles we do have. However, without the different models we cannot have any idea about which direction to put effort to best secure further study.

But I realize now that these people were not in science; they didn’t understand it. They didn’t understand technology; they didn’t understand their time.

This message is a reply to:
 Message 88 by simple, posted 10-16-2005 10:32 PM simple has replied

Replies to this message:
 Message 94 by simple, posted 10-17-2005 10:57 PM sidelined has replied

  
simple 
Inactive Member


Message 93 of 129 (252548)
10-17-2005 10:47 PM
Reply to: Message 91 by crashfrog
10-17-2005 7:58 AM


tale of two tales
Alternate to something appearing for no apparent reason, or creator involved, yes.(though some might suppose God meant eden as a fable and the singularity magic act was really where it's at).

This message is a reply to:
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simple 
Inactive Member


Message 94 of 129 (252551)
10-17-2005 10:57 PM
Reply to: Message 92 by sidelined
10-17-2005 9:29 AM


limiting claims
quote:
Why do you always reference to something other than the physical universe as though that had any meaning? What does you mean by not physical my friend?
.... Science operates in the region between known and unknown and has found physical explanations for all the questions
Not all. Not what was before the big bang, or what caused the somethin from nothin. Not where life from nonlife appeared. Not for sure whether this physical universe is infinite or finite. Not whether there are ghosts or not. I would expect there would be 'physical explanations' for things in a physical universe, but not beyond. Beyond doesn't just mean far away, but long ago, or in the future.
quote:
That we have different possible scenarios for further study of leading edge physics is not as result of being clueless but because of the difficulty of producing the conditions necessary to test the modles we do have.
This is important, in other words we have definite limits.
quote:
However, without the different models we cannot have any idea about which direction to put effort to best secure further study.
I understand, make the best with what you do have, and the limits under which you must do this.

This message is a reply to:
 Message 92 by sidelined, posted 10-17-2005 9:29 AM sidelined has replied

Replies to this message:
 Message 98 by sidelined, posted 10-18-2005 12:39 PM simple has replied

  
madeofstarstuff
Member (Idle past 5929 days)
Posts: 47
Joined: 08-12-2005


Message 95 of 129 (252562)
10-18-2005 12:55 AM
Reply to: Message 85 by cavediver
10-12-2005 1:03 PM


Re: Relative lengths
Cavediver:
Thus you can still have A and B appearing at 90 degrees and at the declared distances, but the line AB will certainly not be the pythagorean distance, nor the angles OAB and OBA the expected trignometric values.
So how do you distinguish between the pythagorean and the nonpythagorean distance? If you look out and are justified in seeing the pythagorean distance and have no reason to believe otherwise, with respect to what is there more than the pythagorean distance? It seems as though there is some standard of distance in a certain inertial frame of reference as long as you have no knowledge of the increased density of space. This "extra" space is seemingly packed into an apparent pythagorean amount of space, so why would you need to know the curvature was there to accurately render your environment? Why should it not be apparent?

This message is a reply to:
 Message 85 by cavediver, posted 10-12-2005 1:03 PM cavediver has replied

Replies to this message:
 Message 96 by cavediver, posted 10-18-2005 5:08 AM madeofstarstuff has replied

  
cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 96 of 129 (252613)
10-18-2005 5:08 AM
Reply to: Message 95 by madeofstarstuff
10-18-2005 12:55 AM


Re: Relative lengths
You will measure the real distance. You can measue the distance to A from O and B from O. But travel to A and measure AB, you will find it not equal to sqrt(OA^2 + OB^2). By taking enough measurements like this, you can build up a picture of the local curvature.

This message is a reply to:
 Message 95 by madeofstarstuff, posted 10-18-2005 12:55 AM madeofstarstuff has replied

Replies to this message:
 Message 97 by madeofstarstuff, posted 10-18-2005 10:19 AM cavediver has replied

  
madeofstarstuff
Member (Idle past 5929 days)
Posts: 47
Joined: 08-12-2005


Message 97 of 129 (252700)
10-18-2005 10:19 AM
Reply to: Message 96 by cavediver
10-18-2005 5:08 AM


Re: Relative lengths
OK, thats what I thought, that is strange. So if I were standing at O and saw something traveling at constant v toward AB, what would their motion look like from O as they progressed (continually from their perspective at v) from A to B?

This message is a reply to:
 Message 96 by cavediver, posted 10-18-2005 5:08 AM cavediver has replied

Replies to this message:
 Message 99 by cavediver, posted 10-18-2005 1:41 PM madeofstarstuff has replied

  
sidelined
Member (Idle past 5908 days)
Posts: 3435
From: Edmonton Alberta Canada
Joined: 08-30-2003


Message 98 of 129 (252738)
10-18-2005 12:39 PM
Reply to: Message 94 by simple
10-17-2005 10:57 PM


Re: limiting claims
simple
Not all. Not what was before the big bang, or what caused the somethin from nothin. Not where life from nonlife appeared. Not for sure whether this physical universe is infinite or finite. Not whether there are ghosts or not. I would expect there would be 'physical explanations' for things in a physical universe, but not beyond. Beyond doesn't just mean far away, but long ago, or in the future.
First off before the big bang is a wrong question since "before" is a temporal term and has no meaning when there is no spacetime in which a before can have logical placement.That something came from nothing is not the likely case either.The universe most likely has existence at a level that is not consistent with the universe we experience since we are constituents of the universe as it is in spacetime.
The background vacuum energy which is a consequence of the principle of uncertainty allows for the "existence" of particles that constantly fluctuate with energy as long as they vanish within a brief enough time period that they do not violate conservation of energy in the universe.
Infinite or finite is far more difficult because a vast enough finite universe is,for all practical purposes, indistinguishable from a truly infinite one.
As for ghosts we can say with pretty good confidence that they are not at all likely.
This is important, in other words we have definite limits.
These are limits imposed by nature as to what is possible given what we already know about the universe
I understand, make the best with what you do have, and the limits under which you must do this
I am not sure you do. The limits are a consequence of the structure that we study not a limit on what we can discover. It is true that there are things we can also never know about the universe since properties such as the speed of light limit prevent any information from reaching us from certain places in the universe.
That does not mean that we fill the gap with anything that takes our fancy since if we do not know about those regions we cannot say anything at all about them for any idea is just as valid as another.

But I realize now that these people were not in science; they didn’t understand it. They didn’t understand technology; they didn’t understand their time.

This message is a reply to:
 Message 94 by simple, posted 10-17-2005 10:57 PM simple has replied

Replies to this message:
 Message 102 by simple, posted 10-20-2005 2:11 AM sidelined has replied

  
cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 99 of 129 (252765)
10-18-2005 1:41 PM
Reply to: Message 97 by madeofstarstuff
10-18-2005 10:19 AM


Re: Relative lengths
You would just see them accelerate (in direction as well as speed), then decelerate but would not discern any force exerted.

This message is a reply to:
 Message 97 by madeofstarstuff, posted 10-18-2005 10:19 AM madeofstarstuff has replied

Replies to this message:
 Message 100 by madeofstarstuff, posted 10-18-2005 2:54 PM cavediver has not replied

  
madeofstarstuff
Member (Idle past 5929 days)
Posts: 47
Joined: 08-12-2005


Message 100 of 129 (252794)
10-18-2005 2:54 PM
Reply to: Message 99 by cavediver
10-18-2005 1:41 PM


Re: Relative lengths
Is that because the time dilation is more prominent than the spatial "contraction"?

This message is a reply to:
 Message 99 by cavediver, posted 10-18-2005 1:41 PM cavediver has not replied

  
madeofstarstuff
Member (Idle past 5929 days)
Posts: 47
Joined: 08-12-2005


Message 101 of 129 (253087)
10-19-2005 2:10 PM


Progression of Events
I tried to get a new thread on this but it was denied, but I'm also not sure whether its relevant to a GR thread, so I will ask anyway because I am curious. When something, anything, changes from one instant to the next (strictly QED), is this due solely to the exchange of a photon from one electron to the other? I assume that these events, photon exchanges, occur instantaneously. If a body of mass (which is mostly affected by EM radiation) changes in some way (be it momentum or velocity), is this due to an exchange of a photon? Can anything noticeable happen without this exchange? Is absorbing a photon the only way to "realize" anything happened? Lastly, does this indicate that time is discrete in its progression from one "instant" to the next, or has it been shown to be analogous?

Replies to this message:
 Message 104 by cavediver, posted 10-20-2005 9:18 AM madeofstarstuff has replied

  
simple 
Inactive Member


Message 102 of 129 (253254)
10-20-2005 2:11 AM
Reply to: Message 98 by sidelined
10-18-2005 12:39 PM


Re: limiting claims
quote:
First off before the big bang is a wrong question since "before" is a temporal term and has no meaning when there is no spacetime in which a before can have logical placement.
Same can be said of the merge idea, and who knows what else. Space time as we know it only applies to this universe after it came into being, whether created, of from the tiny universe you suggest.
quote:
That something came from nothing is not the likely case either.
Well, since you really don't know, we could say that, or something else for that matter!
quote:
The universe most likely has existence at a level that is not consistent with the universe we experience since we are constituents of the universe as it is in spacetime.
This is what people who propose another non physical dimension would say also, but there, you would likely sceam for evidence?
quote:
The background vacuum energy which is a consequence of the principle of uncertainty allows for the "existence" of particles that constantly fluctuate with energy as long as they vanish within a brief enough time period that they do not violate conservation of energy in the universe.
So there may be a part of the universe we don't really see, or are uncertain about, but when it comes to vanishing and appearing things, like ghosts, your theorries as to the real explanation are only as good as your imagination.
quote:
I am not sure you do. The limits are a consequence of the structure that we study not a limit on what we can discover.
Speculation. You don't know the limits we can discover.
quote:
It is true that there are things we can also never know about the universe ..
These unknowns also may affect the knowns, and there is no way we can say, then, that there may this other dimension beyond these admitted limits.
quote:
That does not mean that we fill the gap with anything that takes our fancy since if we do not know about those regions we cannot say anything at all about them for any idea is just as valid as another.
This is a good description of what is being attempted with having things like a microscopic universe just appear on the scene, or life from non life.

This message is a reply to:
 Message 98 by sidelined, posted 10-18-2005 12:39 PM sidelined has replied

Replies to this message:
 Message 103 by crashfrog, posted 10-20-2005 8:06 AM simple has not replied
 Message 106 by sidelined, posted 10-24-2005 1:00 AM simple has not replied

  
crashfrog
Member (Idle past 1467 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 103 of 129 (253282)
10-20-2005 8:06 AM
Reply to: Message 102 by simple
10-20-2005 2:11 AM


Re: limiting claims
This is a good description of what is being attempted with having things like a microscopic universe just appear on the scene, or life from non life.
No, those are conclusions based on observation. The difference should be apparent.

This message is a reply to:
 Message 102 by simple, posted 10-20-2005 2:11 AM simple has not replied

  
cavediver
Member (Idle past 3643 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 104 of 129 (253291)
10-20-2005 9:18 AM
Reply to: Message 101 by madeofstarstuff
10-19-2005 2:10 PM


Re: Progression of Events
A bit too busy at the moment to address this, but I will come back to it. Good "question" though, and it does have an important connection to GR so it is not too out of place here. A quick point though... it's not just photon exchange but also graviton exchange. The others we can effectively ignore for your discussion.

This message is a reply to:
 Message 101 by madeofstarstuff, posted 10-19-2005 2:10 PM madeofstarstuff has replied

Replies to this message:
 Message 105 by madeofstarstuff, posted 10-20-2005 1:40 PM cavediver has not replied

  
madeofstarstuff
Member (Idle past 5929 days)
Posts: 47
Joined: 08-12-2005


Message 105 of 129 (253403)
10-20-2005 1:40 PM
Reply to: Message 104 by cavediver
10-20-2005 9:18 AM


Re: Progression of Events
quote:
A bit too busy at the moment
I understand. I appreciate the time you have given me so far. I had also replied to your revealing to me the motion of a thing through a curved space being perceived as acceleration without force. I had wondered if this was due to the time dilation being more prominent than the spatial contraction.
Take your time, I don't plan on having my death event anytime soon, and once again thanks for your time and patience.

This message is a reply to:
 Message 104 by cavediver, posted 10-20-2005 9:18 AM cavediver has not replied

  
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