Register | Sign In


Understanding through Discussion


EvC Forum active members: 65 (9162 total)
3 online now:
Newest Member: popoi
Post Volume: Total: 915,806 Year: 3,063/9,624 Month: 908/1,588 Week: 91/223 Day: 2/17 Hour: 0/0


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   What's the Fabric of space made out of?
jar
Member (Idle past 393 days)
Posts: 34026
From: Texas!!
Joined: 04-20-2004


Message 166 of 284 (193349)
03-22-2005 11:20 AM
Reply to: Message 165 by sidelined
03-22-2005 11:12 AM


Actually, I found it interesting because it showed both references. Since the ball stayed in line with the vertical post (or line, I can't remember which), it showed the perspective of the rider as well as the perspective of the person standing on the ground.
But are there really two lines, or do we only perceive the line based on our point of reference?

Aslan is not a Tame Lion

This message is a reply to:
 Message 165 by sidelined, posted 03-22-2005 11:12 AM sidelined has replied

Replies to this message:
 Message 167 by sidelined, posted 03-22-2005 11:34 AM jar has replied

  
sidelined
Member (Idle past 5907 days)
Posts: 3435
From: Edmonton Alberta Canada
Joined: 08-30-2003


Message 167 of 284 (193367)
03-22-2005 11:34 AM
Reply to: Message 166 by jar
03-22-2005 11:20 AM


jar
But are there really two lines, or do we only perceive the line based on our point of reference?
Both.Our frame of reference is local to our motion,and thus the paths are valid to the particular frame of reference only.The rider,for the purpose of his frame of reference views the ground as moving past him while he remains stationary.The same is true for the person viewing from the ground.
In common sense though. we cannot concieve of the rider considering himself motionless since that goes against what our senses register.It is one of the ways in which our minds everyday experience prevents us from percieving the underlying actualities.

And since you know you cannot see yourself,
so well as by reflection, I, your glass,
will modestly discover to yourself,
that of yourself which you yet know not of

This message is a reply to:
 Message 166 by jar, posted 03-22-2005 11:20 AM jar has replied

Replies to this message:
 Message 168 by jar, posted 03-22-2005 11:53 AM sidelined has replied

  
jar
Member (Idle past 393 days)
Posts: 34026
From: Texas!!
Joined: 04-20-2004


Message 168 of 284 (193379)
03-22-2005 11:53 AM
Reply to: Message 167 by sidelined
03-22-2005 11:34 AM


we cannot concieve of the rider considering himself motionless since that goes against what our senses register.
I was lucky enough to have been around during the period when there were still steam engines. As a child I would often wander down to Camden Yard. Generally, when they found a child wandering around the switching yard they would run them off, but because I was persistent I eventually was taken underwing by some of the brakemen and engineers.
If you have never visted the Round House at Camden Yards you have missed visting the Cathedral of Our Lady of Industrial America. The Round House, as implied, is a large round building. Inside, completely within the confines, is the turntable. I was fortunate enough to be able to sit in the cab of an Allegany (the heaviest, most powerful steam locomotives ever built) as it was run into the Round House. Once we were fully on the turntable the machinery went to work and revolved the world outside until we were aimed 180o from our original direction.
I know for a fact that it was the world outside that moved since I remained stationary in the cab.

Aslan is not a Tame Lion

This message is a reply to:
 Message 167 by sidelined, posted 03-22-2005 11:34 AM sidelined has replied

Replies to this message:
 Message 169 by sidelined, posted 03-22-2005 3:51 PM jar has replied

  
sidelined
Member (Idle past 5907 days)
Posts: 3435
From: Edmonton Alberta Canada
Joined: 08-30-2003


Message 169 of 284 (193468)
03-22-2005 3:51 PM
Reply to: Message 168 by jar
03-22-2005 11:53 AM


jar
I know for a fact that it was the world outside that moved since I remained stationary in the cab.
And what do you observation do you base this on? If you were to view it as the cab being still and the world moving instead would you not remain stationary in this scenario as well? Is there anything that would appear different between either set of conditions?

This message is a reply to:
 Message 168 by jar, posted 03-22-2005 11:53 AM jar has replied

Replies to this message:
 Message 170 by jar, posted 03-22-2005 4:16 PM sidelined has replied

  
jar
Member (Idle past 393 days)
Posts: 34026
From: Texas!!
Joined: 04-20-2004


Message 170 of 284 (193475)
03-22-2005 4:16 PM
Reply to: Message 169 by sidelined
03-22-2005 3:51 PM


If you were to view it as the cab being still and the world moving instead would you not remain stationary in this scenario as well?
But that's exactly what did happen?

Aslan is not a Tame Lion

This message is a reply to:
 Message 169 by sidelined, posted 03-22-2005 3:51 PM sidelined has replied

Replies to this message:
 Message 171 by sidelined, posted 03-22-2005 6:01 PM jar has replied

  
sidelined
Member (Idle past 5907 days)
Posts: 3435
From: Edmonton Alberta Canada
Joined: 08-30-2003


Message 171 of 284 (193501)
03-22-2005 6:01 PM
Reply to: Message 170 by jar
03-22-2005 4:16 PM


jar
Sorry jar that was my error in reading your post.

This message is a reply to:
 Message 170 by jar, posted 03-22-2005 4:16 PM jar has replied

Replies to this message:
 Message 172 by jar, posted 03-22-2005 6:07 PM sidelined has not replied

  
jar
Member (Idle past 393 days)
Posts: 34026
From: Texas!!
Joined: 04-20-2004


Message 172 of 284 (193503)
03-22-2005 6:07 PM
Reply to: Message 171 by sidelined
03-22-2005 6:01 PM


OT but we have time still
If you ever do get a chance to visit Camden Yards and the B&O Museum, it is well worthwhile and a great lesson in relativity. And when you're done, walk a ways down to Pier One Pratt Street and visit the Aquarium.

Aslan is not a Tame Lion

This message is a reply to:
 Message 171 by sidelined, posted 03-22-2005 6:01 PM sidelined has not replied

  
Buzsaw
Inactive Member


Message 173 of 284 (193526)
03-22-2005 8:03 PM
Reply to: Message 155 by Asgara
03-17-2005 7:18 PM


Maybe you and Sylas could work with this analogy. A loaf of raisin or nut bread. When you set this dough to rise it is much smaller than it will become...the dough rises(expands) yet the nuts/raisins do not get bigger.
As a matter of fact, it takes energy for anything to expand. Both analogys make that point. This's my greatest problem with expansion of space. I don't see that anyone has cited any energetic properties of space which would effect expansion of anything. As I've long contended, space must contain things which have energy to expand in any observations or explanations of what is percieved to be expanding space. Space itself, imo, is a vaccum in which things and forces like galaxies, electromagnatism and gravity can be introduced into. What alleged properties of an absolute vacuum have the capability of expansion? This's the logic I use and no amount of mathmatics is going to change that until these questions are logically and sensibly answered.

The immeasurable present is forever consuming the eternal future and extending the infinite past. buzsaw

This message is a reply to:
 Message 155 by Asgara, posted 03-17-2005 7:18 PM Asgara has not replied

Replies to this message:
 Message 174 by Sylas, posted 03-22-2005 10:25 PM Buzsaw has replied
 Message 212 by Trae, posted 03-26-2005 3:05 AM Buzsaw has replied

  
Sylas
Member (Idle past 5259 days)
Posts: 766
From: Newcastle, Australia
Joined: 11-17-2002


Message 174 of 284 (193546)
03-22-2005 10:25 PM
Reply to: Message 173 by Buzsaw
03-22-2005 8:03 PM


What alleged properties of an absolute vacuum have the capability of expansion?
Its geometry. You've been given this answer many times, and your only response is to shut your mind to it.
This's the logic I use and no amount of mathmatics is going to change that until these questions are logically and sensibly answered.
It is illogical and irrational to refuse to accept the mathematics. The expansion of space is, as a matter of fact, tied to the stress-energy tensor; but that gets into deep waters of tensor calculus again. Your intuitions about energy are not going to be reliable here. You have to learn a lot more physics before you can say anything sensible about energy in relation to expansion. Of course it is now obvious that you will prefer to trust your intutition rather than the collective work of several generations of working physicists. Calling this behaviour logical or sensible is a travesty.
Cheers -- Sylas

This message is a reply to:
 Message 173 by Buzsaw, posted 03-22-2005 8:03 PM Buzsaw has replied

Replies to this message:
 Message 184 by Buzsaw, posted 03-23-2005 11:43 AM Sylas has not replied

  
Phat
Member
Posts: 18262
From: Denver,Colorado USA
Joined: 12-30-2003
Member Rating: 1.1


Message 175 of 284 (193548)
03-22-2005 10:41 PM
Reply to: Message 164 by sidelined
03-22-2005 11:06 AM


As the train is moving, the object drops in a combgination of forward momentum and downward gravity?

This message is a reply to:
 Message 164 by sidelined, posted 03-22-2005 11:06 AM sidelined has replied

Replies to this message:
 Message 176 by sidelined, posted 03-22-2005 11:39 PM Phat has replied

  
sidelined
Member (Idle past 5907 days)
Posts: 3435
From: Edmonton Alberta Canada
Joined: 08-30-2003


Message 176 of 284 (193562)
03-22-2005 11:39 PM
Reply to: Message 175 by Phat
03-22-2005 10:41 PM


Phatboy
Yes it does from the perspective of the person on the ground.The apparent path for them is a parbola while the person on the train witnesses the ball falling straight down.
The point here is that it is not obvious at first glance what is meant by a "real" path in space since both observations are valid but contradictory in terms of standard conceptions of Euclidean space.Common sense tells us that a path cannot be a straight line between 2 points and also be a parabolic arc between those same 2 points since one traverses a greater length than the other.

This message is a reply to:
 Message 175 by Phat, posted 03-22-2005 10:41 PM Phat has replied

Replies to this message:
 Message 177 by Phat, posted 03-23-2005 1:46 AM sidelined has replied

  
Phat
Member
Posts: 18262
From: Denver,Colorado USA
Joined: 12-30-2003
Member Rating: 1.1


Message 177 of 284 (193580)
03-23-2005 1:46 AM
Reply to: Message 176 by sidelined
03-22-2005 11:39 PM


So even using such equipment as the space telescope, how do we effectively chart our position in the vast sceme of things? How do we know how fast objects are travelling? If we are looking back through time as we look out in space, how do we know if it all is still there? After all, what we see is billions of years ago.

This message is a reply to:
 Message 176 by sidelined, posted 03-22-2005 11:39 PM sidelined has replied

Replies to this message:
 Message 178 by Funkaloyd, posted 03-23-2005 5:18 AM Phat has not replied
 Message 179 by sidelined, posted 03-23-2005 8:43 AM Phat has not replied

  
Funkaloyd
Inactive Member


Message 178 of 284 (193619)
03-23-2005 5:18 AM
Reply to: Message 177 by Phat
03-23-2005 1:46 AM


We don't know. Interestingly enough, if the Sun were to explode now, we would have no way of knowing for 8 minutes.
We can measure the speed of objects in space relative to other objects. Figuring out where we are in the Universe is theoretically impossible; we know that we live in the middle of the observable Universe, but that's about it.

Please correct me if I'm wrong, I'm here to learn.

This message is a reply to:
 Message 177 by Phat, posted 03-23-2005 1:46 AM Phat has not replied

Replies to this message:
 Message 180 by sidelined, posted 03-23-2005 8:54 AM Funkaloyd has not replied

  
sidelined
Member (Idle past 5907 days)
Posts: 3435
From: Edmonton Alberta Canada
Joined: 08-30-2003


Message 179 of 284 (193648)
03-23-2005 8:43 AM
Reply to: Message 177 by Phat
03-23-2005 1:46 AM


Pharboy
So even using such equipment as the space telescope, how do we effectively chart our position in the vast sceme of things?
One of the postulates of special relativity was that the speed of light is the fastest that information can travel. We look out at a star and we view that star as it was in its past.When we view it is in our local present time frame.We further postulate that the laws of physics are universal.With these two postulates in hand we find that theory is consistent with observation.
How do we know how fast objects are travelling?
We measure them relative to our local time frame while being aware of the speed limit imposed by light.
If we are looking back through time as we look out in space, how do we know if it all is still there?
It is where it is only in our reference frame.The position in the sky is the location it possesed in spacetime when the light left its surface how ever many light years ago.Since we can make measurements of the speed of light and we know that the laws are universal we can accurately predict the corrections needed if we wish to predict the location of the light image that is presently leaving its surface.
Remember the postulate of universality of the laws of physics? Since the forces and interactions that we deal with here in our local time frame are the same as those "out there" and since this postulate has been found to be consistent with the observations that we make we can actually show the logical process that verifies the object is still around even though it is in motion and has since relocated.

This message is a reply to:
 Message 177 by Phat, posted 03-23-2005 1:46 AM Phat has not replied

Replies to this message:
 Message 181 by jar, posted 03-23-2005 9:44 AM sidelined has replied

  
sidelined
Member (Idle past 5907 days)
Posts: 3435
From: Edmonton Alberta Canada
Joined: 08-30-2003


Message 180 of 284 (193649)
03-23-2005 8:54 AM
Reply to: Message 178 by Funkaloyd
03-23-2005 5:18 AM


Funkaloyd
Please correct me if I'm wrong, I'm here to learn.
You are doing well.Especially this statement.
Figuring out where we are in the Universe is theoretically impossible;
Since every place in the universe must measure every other place in the universe only by local frame of reference and not some motionless position in spacetime to which everything can be referenced it is impossible period.The same is true of every other part of the universe.

This message is a reply to:
 Message 178 by Funkaloyd, posted 03-23-2005 5:18 AM Funkaloyd has not replied

  
Newer Topic | Older Topic
Jump to:


Copyright 2001-2023 by EvC Forum, All Rights Reserved

™ Version 4.2
Innovative software from Qwixotic © 2024