Curved Space

Einstein theoretically explained gravity by mass curving space, he used geometry in his explanation.

As there is no direct method of testing whether space is curved by mass or not then indirect infers have propogated the belief that curved space is fact when it is not.

Assume space is curved around the mass of the Earth, this is difficult as the nearer the Earth the more space should be curved. Why would curved space make objects fall straight down? It would be logical for objects to follow the path of the curved space.

If we simply curve space at the limit of the Earth`s gravitaional field and allow objects to fall towards the planet there is a problem with any space inside that curvature. take the apple...it has no idea that space is curved miles up so when it is free it has no idea which way is up or down.

Space is space whether it is curved or not and has no properties to affect anything really, no one has ever produced any curved space in a lab experiment.

The fabric of curved space is imortalised in that illustration of a latex sheet...the Earth is suspended in an indent with no visible means of support...there is space below the planet but no space above it. If that illustration is completely wrong then why not produce an illustration that is right? It cannot be done that is why.

If we draw a circle around the Earth to represent curved space and then draw a smaller circle around the Moon to represent the curved space around that then we get the anomaly that the curved space around the Moon cannot reach anywhere near the Earth to affect tides at all.

Time and again no attempt is made to actually grasp how theory works in practice as if it does not matter that it is not even possible in reality, as long as it fits the theory and some scribbled maths can support it then it is in.

john

It apears that your asumption is that a curve has a beginning but NO ending. Yrt if it is an uniform curve it will terminate where it began.

Interesting question and I'm no physics professor but wouldn't particles coming from different directions each have their own perception (if thats the right word) of the latex sheet and travel along their own version of it. And therefore as there is an infinate amount of directions a particle could come from theres an infinate number of latex sheets?

Edited to make more sense (I think)

It's unclear whether you support this theory or not.

The problem is that people with elementary physics education are trying to understand theories that require doctorate level education or more. This is cutting edge stuff, not F=mA, or even E=mc^2.

Any theory that requires measurements within 4 or more dimensions is impossible to accurately illustrate because we can only perceive 3 spatial dimensions. We can only infer existence of a fourth spatial dimension by the existence of anomalies that cannot be explained in conventional three dimensional geometry.

Think of a creature that lives entirely within 2 spatial dimensions, and can perceive only those 2 dimensions. Their sensory apparatus is for whatever reason unable to measure the third spatial dimension. Within this world, there is only side to side and back and forth movement, and it only occurs upon the application of force.

Now imagine that their 2 dimensional universe exists within our three dimensional universe. Take particular objects within this 2 dimensional universe and pull that item up or down in the third dimension. Although the denizens of that 2 dimensional universe will not be able to perceive that movement (since they can't understand the third dimension), they will experience the results - the two dimensions they can perceive will become warped by the movement into the third dimension. They may experience unexplained acceleration of objects towards the point you are moving.

From this they may infer the existence of our third spatial dimension, although they will never directly perceive it.

Now scale this up. We live in a three dimensional world. There are certain phenomena that cannot be explained within three dimensional geometry. Gravity being one of them. Massive objects cause deviation in the course of objects passing by them. Light even changes course around massive objects. This is consistent with the warping of three dimensional space within a fourth dimension.

Much like a heavy weight warps a two dimensional rubber sheet into the third dimension, so a very massive object warps three dimensional space into the fourth dimension.

Clear?

ministumblin that's kinda what I was trying to explain, obviously yours is much easier to comprehend.

Actually, there have been a few experiments that demonstrated this clearly.

You have to understand that the "curvature" is not really a physical curvature of 3-D space in the way you think. It's a curvature of spacetime, the 4-dimensional quantity.




This is incorrect. We've moved past the point where space is inherently propertyless. There's no possible theory that accepts that space has properties that can explain the things we observe.

General Relativity represents space as a set of tensor fields. This is a very advanced branch of mathematics and it's very hard to get a grasp on how this stuff works without a sufficient grounding in mathematics, particularly advanced calculus.




Again, the problem here is a lack of understanding of the examples. The latex sheet is a 2-dimensional sheet "bent" in a 3-dimensional environment. It's an analog. A visual aid. Nothing more. In reality, 3-dimensional space is "bent" in a 4-dimensional spacetime. Space itself is locally warped by the presence of mass.

Surely you don't think Einstein was so dumb that he didn't recognize that the rubber sheet analogy wasn't a true representation of spacetime?

My problem with this post is that you clearly lack the necessary education to fully comprehend the current state of astrophysics and particle physics, but you're not letting that stop you from making declarative statements about what the current scientific theories lack or don't explain. But you don't understand them well enough to make those statements.

You're obviously a smart guy, you just lack the education necessary to understand this stuff. If you go back to the beginning of understanding modern relativity, and do it this time with an open mind looking for understanding instead of being critical, there is truly a lot you can learn.

Gee thanks to everyone who replied it is much appreciated.

I like to respond to everyone so will do so in this one posting.

WASH: I am asking the question what exactly does curved space mean in reality, your reply simply infers a bubble which around the Earth creates the problems I outlined.

FUZZY: I liked your reply by virtue of the fact it represented original thinking rather than quoting standard theory. From what I gather a number of latex sheets would only work in one direction and not if you tried to establish a network around the planet as each latex sheet interferes with the others creating distortion.

MINI: I do not see this as a matter of supporting anything, if we simply support something then when do we ever question it? I am asking the question of reality as we know it which does not include imaginations of any kind such as other dimensions or concepts such as mathematics for they are dealt with fully in the theory. Theory as it stands supports itself so there is no point in trying to prove the theory wrong what is needed is an unbiased seperate view and for that I use logic. It is the imaginary use of dimensions we do not know exist and examples where one is asked to imagine the dimensions do exist that I wish to defer from in order to grasp the reality of whether in fact curved space is viable. I could of course jump on the theory bandwagon and not attempt to question it at all.

JONNYTHAN: Spacetime is a concept, you can take time out of the universe and nothing at all changes because it is not reality...for something to mean something it has to have substance and time has no substance to enable it to do anything at all. This is also true of mathematics, take maths out of the universe and nothing at all changes showing maths to have no real substance in the universe. While theory is included in timespace and mathematics I seek a logic solution based on what is real in the universe that we can all agree on. As you walk down the street are we to imagine some invisble curved space wrapped around you keeping you on the planet? it is the theory and the mathematics that lack a proper understanding of any real explantion of exactly how and where space curves in reality. The theoretical and mathematical explantions depend on faith and it is a free choice for the individual to choose to have faith that space is indeed curved without any real illustration of exactly how that works in the real world. I choose to question that space even if curved can have any affect different from empty straight space if you like. I am asked to believe in a god and I am asked to believe in curved space but no one wants to answer the questions directly so I remain unconvinced that is all.

john

The problem is that the existence of a fourth spatial dimension is a pre-requisite for curved space-time. But we cannot perceive said dimension. Ergo if you take it out of the equation on account of it being non-observable, of course the theory will fall apart.

Logic is in fact exactly what leads us to the theory of curved space time, as I feel I illustrated well using the two dimensional universe model. They could not directly perceive the third spatial dimension, but the existence of warping in the two dimensions logically leads them to assume there is something happening that they can not perceive. That further leads to them inferring the existence of a third dimension, through which their two dimensions have curved.

This is exactly what has happened in our three dimensional universe. The bending of light around massive objects cannot be explained within the constrains of a three dimensional universe. Introducing another dimension through which the other three are curved explains things quite nicely. Will this always be the prevalent view? Maybe not. But as long as that theory most closely describes what we actually see in the physical universe, it will remain.

Mini, the theory as it stands is not in question...it is fine.

What I am asking is for you to explain this theoretical curved space for the apple that is free to fall in any direction. Are you saying the apple is individually wrapped in this extra dimension forcing it to fall in one direction only? It is the application of the theory of curved space in reality that is the crux of the matter.

Can you explain how the Moon with the capability of only curving space of any dimension 1/6th that of the curved space the Earth can affect tides? See the gravitational affect using curved space for the Moon and Earth does not add up to the Moon having any affect on Earth at all based on the much smaller curvature of space it commands compared to the Earth. The theory might appeal for light bending around mass but it has to work for every other body affected by gravity and this does not appear to be the case with local objects like an apple or the designated role of the Moon with regard to tides.

john

I'm more than happy to answer any questions directly.

However, you lack the education and knowledge necessary to ask any meaningful questions about astrophysics, topology, and general relativity. I suggest you start with more basic questions.

I cannot stress strongly enough that you simply have no idea what you're talking about. Furthermore, you are apparently unwilling to learn - only baselessly attack.

We are trying to educate you, and you are unfortunately having none of it. Close your mouth and open your eyes - this way you may learn something.

jonnythan,

I am asking questions and I am not getting any answers apart from theory, this is an opportunity for anyone who understands the theory to apply it to the apple and the Moon scenarios using as many dimensions as they like and as many latex sheets as they like to explain exactly how curved space works on local objects.

Are your extra dimensions wrapped around the apple, are your latex sheets wrapped around the apple? If you do not know that is fine because I am pretty certain no scientist has actually taken any time to look at the problem in reality because science should be based on reality at some level.

Look theory has imagined singularities, imagined dark matter, imagined dark energy, imagined other dimensions and imagined curved space none of which can be shown to be fact in reality...with so much imagination don`t you think someone should look at stuff that is not imagined but actually factually what everyone knows is factual?

A singularity is a simple concept which needs hardly any thought to understand, curved space is not difficult when used to explain light bending around mass so the theory is simple enough. If everyone else wants to accept the theory without looking at any implications then this is the wrong thread to be on, I do not swallow anything unless it adds up and curved space does not add up so I am asking questions.

john

You are asking questions based on fundamental misunderstandings.

If you want to come here and state flat-out that Einstein - and essentially every physicist to have worked in the last 60 years - completely wrong, stupid, and blind, so be it.

But if you're going to say that, you better back it up. And so far, the only thing you've done is prove, with every single post, that you completely lack even the most basic physics education.

You have zero knowledge of the physics or mathematics involved. And, apparently, zero knowledge of formal logic.

jonnythan,

I hardly think asking how exactly curved space affects an apple directly can be based on any misunderstanding do you?

See it is easy to theorise about light bending around a large mass and come up with curved space but it is not so easy to explain directly curved space around the apple which is free to fall in any direction.

If you understand curved space you will tell me exactly how space is curved around the apple locally that forces it to fall in one direction only.

The theory explains curved space on a large scale but I am asking you to explain it on a small scale and you have no answer because it is not in the theory because no one has even bothered to look at the problem.

Curved space cannot even work on the local Moon/tides problem yet no one has illustrated curved space to show it can affect tides...someone is slacking don`t you think?

As far as my apple example is concerned no one has a clue how curved space is supposed to be illustrated for that..another singular latex sheet perhaps?

If you do understand curved space theory answer my questions.

I am saying my questions cannot be answered by you or anyone else for that matter.

john

How am I supposed to explain it to you?

You're asking me to explain calculus to a person who is struggling to understand arithmetic.

You're saying that General relativity - Albert Einstein's baby, his most precious theory, his most masterful work, which has been confirmed by experiment after experiment - can't even explain how the Moon exerts a gravitational influence on the Earth.

What you need is a basic physics education. I cannot explain general relativity to you because you lack the necessary background to understand it.

jonnythan,

As you do not understand the question perhaps another poster can because it does not involve calculus, it simply requires anyone with curved space theory behind them to demonstrate exactly how this curved space acts upon the apple.

As far as the Moon question is concerned I say using the curved space example that the Moon would need to curve space as much as the Earth to affect tides...it is not difficult in simple terms to show me how the Moon can curve space as much as the Earth to affect tides if there were an answer but as you confirm there is no answer. Now if you want to sweep this under the carpet with no explantion then you are correct you cannot answer me.

john