What's the Fabric of space made out of?

buzsawDo you have Real Player installed on your computer? If so, how about checking out this site to get a taste of the problem facing common sense when dealing with world we live in? Page RedirectionEnjoy!

NosyNed I have pretty much devoured anything written by him{or about him} and I am sending away for the lectures on physics and gravitation to see if I cannot really kick up my understanding of things by ,say, a factor of a thousand.It is a damn shame that we lost a mind of such clarity and insight{not to mention wit}and I think the best lesson of his life was the curiousity that he always kept about the world. What an incredible feeling it must have been to have had such a grasp of so much of the actual workings of the world.

Sylas I am not sure this is the case at all Sylas. It is likely that the life he has lived has not exposed him to a great deal of the necessary tools for delineating facts from fancy.It is also quite possible that the understandings he does have are not correct to begin with.If we were to start with simple concepts such as laws of motion and the consequence of those laws before taking it up a notch and gradually fill in the misconceptions that I am sure are there we would at the least be able to have some good debates that we could possibly use simple experiments to demonstrate with.This I believe is easier than trying to convince Buz of the veracity of quantum mechanics or general relativity.Since we do not have access to gravity probes or particle accelerators it cannot begin to be possible to show how the model bears out in tests of these theories.Anyway it is just a thought to consider eh?

buzsawI know this is not in the complete context of the present direction in this thread but concerning space I was wondering if you might apply some reasoning to the following thought experiment.A train is travelling down the tracks beside a railway crossing moving at a constant speed.A man aboard the train drops a steel ball from the window of this passing train and from his vantage point on the train the ball{ignoring air resistence to understand the forces involved} appears to fall in a straight line through space to the ground moving past his train.
At the same moment a man on the side of the tracks looks up to see the misdeed.He watches the ball fall arcing to the ground as a result of the combination of the forward movement of the train and the pull of gravity set it in a parabloic curve.Which is the correct path in space,the straight line or the parabola?

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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

buzsawBump to check up on buzsaw's progress on post# 158.

PhatboyEach path is valid in relativity.Einstein used this thought experiment to show that the proper way to judge events was not through the use of vague terms such as space but through the use of a defined coordinate system for describing an events location relative to a given fixed local reference frame.The person on board the train can consider himself and his train {moving at a constant speed} as motionless and the surrounding countryside as being in motion as far as his local reference frame is concerned.The same holds true for a man at the side of the tracks and is,of course,in common sense the "real" way the world acts.It is unfortunately not correct as far as special relativity is concerned.We could reverse the direction of the balls' origin of flight to the man on the ground and we would find that the man on the train still would observe a parabolic path while the man on the ground sees a straight line.The consequence of this thought experiment is that there is no absolute frame of reference valid for all localities in the universe.So we delve a little deeper into this and we find things we did not see before.In the first case{the man on the train}observes the ball to move in a straight line while the man on the ground sees it arc,and the same occurs when we reverse the origin of flight to the man on the ground so something is common to both situations.Let us compare the paths.One is a straight line and one is curved. Since both parties witness the same origin and destination for the ball but the path of one {the arc} traverses a greater distance than the other{straight line} by definition what does your common sense tell you is happening?What must be altered between the two reference frames?

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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

PhatboyExactly! Now how must the time change for the two paths to be able to occur simultaneously?This message has been edited by sidelined, Tue, 2005-03-22 09:07 AM

jarYes that would be the view to a person who's reference frame is the ground. To the rider the object appears to fall in a srtaight line.
So we have two paths of unequal length occuring for the same event.As Phatboy surmised time is altered,but how?

jar 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.

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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

jar 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?

jarSorry jar that was my error in reading your post.

PhatboyYes 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.

Pharboy 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. We measure them relative to our local time frame while being aware of the speed limit imposed by light. 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.

Funkaloyd You are doing well.Especially this statement. 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.

jar Here is where things get tricky.Since we cannot judge the location of an event in spacetime except by our local frame of reference,we can only speak of the temporal quality we define as now in our frame of reference.The object we view has a different frame of reference locally and a different now which is defined by that local frame of reference.There is no absolute frame of reference to which we can attach a meaningful now that is coincidental with both locations.
Since the postulate that the laws of physics are universal is consistent with observation and the predictions of theory we are able to express the confidence that the object is located at a given area of the sky based on the distance in light years and the proper motion of the bodies through space.

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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