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Author | Topic: What's the Fabric of space made out of? | |||||||||||||||||||||||
jar Member (Idle past 421 days) Posts: 34026 From: Texas!! Joined: |
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
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sidelined Member (Idle past 5935 days) Posts: 3435 From: Edmonton Alberta Canada Joined: |
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
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jar Member (Idle past 421 days) Posts: 34026 From: Texas!! Joined: |
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
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sidelined Member (Idle past 5935 days) Posts: 3435 From: Edmonton Alberta Canada Joined: |
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?
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jar Member (Idle past 421 days) Posts: 34026 From: Texas!! Joined: |
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
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sidelined Member (Idle past 5935 days) Posts: 3435 From: Edmonton Alberta Canada Joined: |
jar
Sorry jar that was my error in reading your post.
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jar Member (Idle past 421 days) Posts: 34026 From: Texas!! Joined: |
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
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Buzsaw Inactive Member |
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
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Sylas Member (Idle past 5287 days) Posts: 766 From: Newcastle, Australia Joined: |
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
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Phat Member Posts: 18343 From: Denver,Colorado USA Joined: Member Rating: 1.0 |
As the train is moving, the object drops in a combgination of forward momentum and downward gravity?
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sidelined Member (Idle past 5935 days) Posts: 3435 From: Edmonton Alberta Canada Joined: |
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.
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Phat Member Posts: 18343 From: Denver,Colorado USA Joined: Member Rating: 1.0 |
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.
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Funkaloyd Inactive Member |
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.
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sidelined Member (Idle past 5935 days) Posts: 3435 From: Edmonton Alberta Canada Joined: |
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.
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sidelined Member (Idle past 5935 days) Posts: 3435 From: Edmonton Alberta Canada Joined: |
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.
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