Question about gravity and the 'rubber sheet' demonstration

[Master_Ghost_Knight]

I went to the local library to ask about that....
the 'librarian' seemed very confused :roll:

It is just natural; librarians usually are people with an education in literature and not science and mathematics.

Well, that sucks. If it's as important as you say, though, i don't have much choice if I want to understand any of this stuff. Noq, what level of math *(calc, trig, etc) do i need to make sure to master before delving into this?

You are not seriously considering self tutoring this stuff are you? This is college level stuff; most people rather get electrocuted then to go through all this.
It is better that you really get some professional education.

Anyways the books when addressed in order are good to build up from the bottom of a college level math, basic mathematical skills are important (including but not limited to calculus and trigonometry). However if my memory doesn't trick me the book introducing to Real Analysis is going to build you up from 1+1 to what you need on any subject, and it includes smacking down the wrong notion that general students come out of high school whit. Basically your real contact with what really is math starts there. That book it will then take you to a trip to recursive additions on to series and special results (basically teach you how to use those weird E look alike operators that are really neat to simplify allot of stuff, oh and the popular proof of 0.99999999999"¦=1 is there to I believe), then it will start to get into differential/integration analysis and how to use those tools (perhaps the most important) and finally I believe there is some topology as well (fields, divergence, rotational, flux).
The Linear Algebra is also an accessible content to some one that is just starting, if you take that conjointly with introduction to analysis won't hurt you. It will teach you allot of valuable tool s that will appear several times, such as matrix operations, linear transformations, notions like dimension, nullity and so on.
The complex analysis is the next logically step after the previous 2, it requires several notions found in the previous, it will teach you how to move around with complex numbers, it will have some more topology and it will dive back into some results for differential/integration analysis and some special results like the theorem of residues (useful to solve some forms of singularities).
Finally there is the differential equations (which relates functions with their derivatives like an equation), going to trivial solution to particular solution and several methods of solving particular problems.

I don't remember very well the total extent of the content of each book but I guess that was it. And I guess it is more the enough to build you from the ground up if you don't get lost in the middle of the ocean.

Good Luck!

 

[Zylstra]

I still don't see why matter should move into such 'gravity wells' :?: :facepalm:

Do you wonder why a rock rolls downhill? If you don't? It is time for you to STFU.[/quote]

Yours is perhaps the most retarded response anyone has ever given to any post on LoR. Your ad hom and implied circular 'reasoning' is befitting Geerup

 

[ImprobableJoe]

Yours is perhaps the most retarded response anyone has ever given to any post on LoR. Your ad hom and implied circular 'reasoning' is befitting Geerup

You've been wrong before and I pointed it out. Now you are throwing a temper tantrum and calling names. Try again, and try using your brain for a change... although I would be shocked beyond belief if you even bothered...

The Earth forms a gravity well. Rocks roll downhill because of this fact. If you don't understand gravity, stop attacking people who do.

 

[scikidus]

WTF just happened to this thread? It started with someone asking about a model for space-time and now people are yellign at each other? What?

Can we take the arguments somewhere else please?

 

[Zylstra]

You are not seriously considering self tutoring this stuff are you? This is college level stuff; most people rather get electrocuted then to go through all this.
It is better that you really get some professional education.

That would require money :|

Most of the science and political theory I know is self-taaught. In my personal experience,the hardest part about self-tutoring is figuring out a 'plan' and knowing where to turn when you run into a subject, equation, symbol, or concept that I'm not familiar with. I tracked down something over at MIT's OpenCourseWare that I'm hoping will provide a good 'guideline'.

Anyways the books when addressed in order are good to build up from the bottom of a college level math,

\

Can tyou define 'college level math'? I've seen colleges and college students who barely grasp algebra and geometry and high school students who can do the stuff y'all are talkin' about. Right now, I grasp basic euclidean geometry and and what one might call 'elementary 'to 'intermediate' algebra. Unfortunately, I've always had trouble with math, which gets really frustrating given my interest in the physical sciences.

\\basic mathematical skills are important (including but not limited to calculus and trigonometry).

:shock:

Did you just call trig basic mathematics'? Something tells me it's going to be a long time before I I can begin to understand any of this...

However if my memory doesn't trick me the book introducing to Real Analysis is going to build you up from 1+1 to what you need on any subject, and it includes smacking down the wrong notion that general students come out of high school whit. Basically your real contact with what really is math starts there. That book it will then take you to a trip to recursive additions on to series and special results (basically teach you how to use those weird E look alike operators that are really neat to simplify allot of stuff,

Sounds good. I really do need something that will start with the most remedial and fundamental aspects and build from there. When you guys start jumping into the 'higher' maths you're so comfortable with, I feel like barbarian worshiping an airplane and praying for the cargo to come back.. If you've never experienced such feelings of your own ignorance and stupidity, i can assure that they are most unpleasant. I wonder whether this is why so many people develop a hatred for science and turn to religion for mindless reassurance that they need not think at all....

oh and the popular proof of 0.99999999999"¦=1 is there to I believe),

I remember that thread....if I recall, it had something to do with the limitations of our base-10 mathematical representations and why fractions rule infinitely over decimals (1/3 versus .333....). Yeah... I felt stupid in that thread, too (why did it take so long for such a simple explanation to be presented). The concept is pretty simple, as it turns out.

That's the thing about LoR: I love it because i'ts the only board I've really been to where one can get intelligent responses and discuss things reasonably. On the other hand, though, things tend to go over my head quite a bit around here, which dpesn't happen much in daily life and which I still can't get used to...

then it will start to get into differential/integration analysis and how to use those tools (perhaps the most important) and finally I believe there is some topology as well (fields, divergence, rotational, flux).
The Linear Algebra is also an accessible content to some one that is just starting, if you take that conjointly with introduction to analysis won't hurt you. It will teach you allot of valuable tool s that will appear several times, such as matrix operations, linear transformations, notions like dimension, nullity and so on.

If you were here, I would give you my last Guinness :lol:

And I guess it is more the enough to build you from the ground up if you don't get lost in the middle of the ocean.

If i do, you can expect more threads

 

[Zylstra]

You've been wrong before and I pointed it out. Now you are throwing a temper tantrum and calling names. Try again, and try using your brain for a change... although I would be shocked beyond belief if you even bothered...

The Earth forms a gravity well. Rocks roll downhill because of this fact. If you don't understand gravity, stop attacking people who do.

That's circular reasoning. You've said that earth creates a gravity well, so rocks 'fall' towards it. I asked why anything should 'fall into' a gravity well in the first place- that is, I asked why a bend in spacetime should not only effect the path of a passing object but how the bend in spacetime results in the acceleration of matter towards to center of the gravity well. You didn't address my question at all. Rather you restated my initial observation and then attempted to launch a personal attack against me wile making yourself look like an idiot and a jackass.

Meanwhile, Pulsar tried to answer the question and Ghost has taken the time to actually provide resources so that I might learn.

 

[Zylstra]

Why? Why does a bend in gravity result in the acceleration of matter? I already stated that the 'ruber sheet' model is flawed, as the objects on the sheet are drawn by Earth's gravity and merely roll down the sheet because it's in the way- a condition not present IRL, as spacetime does not sit above a large mass of matter (if it did, it would merely push the question back one step while not answering anything) and we do not sit atop of and roll around on spacetime, but travel through it.

If you don't understand gravity, stop attacking people who do.

Says the guy who started attacking someone for asking questions so that he might be come more educated and less ignorant in a most difficult subject of interest :lol:

I was under the impression that LoR believed that people who want to learn should be guided along, not attacked for admitting their own limited knowledge and asking for assistance

 

[e2iPi]

The Earth forms a gravity well. Rocks roll downhill because of this fact. If you don't understand gravity, stop attacking people who do.

So you fully understand gravity?
We have been waiting for you for a very long time, you may even be the Messiah!

Could you help us out with some n-body problems, we have some problems that pop up when we get over 3?

Also, recent observations of an apparent dark flow in galaxy clusters seem to indicate that gravitational force may decrease slower than the inverse square model indicates at certain distances. However observations of the CMBR energy levels have suggested that it decreases faster than the inverse square model. Which one is correct? Do we need to revamp our entire theory of gravity?

What is the reason for the unexplained slowing of the Pioneer spacecraft? Is this also linked to the inverse square issues noted above?

Is dark mater the real reason for the accelerating expansion of the universe or is it due to our incomplete understanding of gravity? Please enlighten us.

Planetary orbits are expanding faster than expected based solely on the sun's loss of mass.

Why have some spacecraft gained more energy than expected from gravity assist maneuvers?

Hell, while you're at it, could you help us out on an issue we've been working on by telling us exactly how gravity fits into quantum mechanics? Do we really need those messy extra dimensions?

The entire scientific community thanks you for your help.

-1

 

[ImprobableJoe]

So you fully understand gravity?
We have been waiting for you for a very long time, you may even be the Messiah!

Everyone understands gravity 99.999% of the time :lol:

Could you help us out with some n-body problems, we have some problems that pop up when we get over 3?

Also, recent observations of an apparent dark flow in galaxy clusters seem to indicate that gravitational force may decrease slower than the inverse square model indicates at certain distances. However observations of the CMBR energy levels have suggested that it decreases faster than the inverse square model. Which one is correct? Do we need to revamp our entire theory of gravity?

What is the reason for the unexplained slowing of the Pioneer spacecraft? Is this also linked to the inverse square issues noted above?

Is dark mater the real reason for the accelerating expansion of the universe or is it due to our incomplete understanding of gravity? Please enlighten us.

Planetary orbits are expanding faster than expected based solely on the sun's loss of mass.

Why have some spacecraft gained more energy than expected from gravity assist maneuvers?

Hell, while you're at it, could you help us out on an issue we've been working on by telling us exactly how gravity fits into quantum mechanics? Do we really need those messy extra dimensions?

The entire scientific community thanks you for your help.

-1

Give me a few years... in the meanwhile, I'm correct on the scale I'm talking about, in the same way that the physics teachers still bother to teach Newtonian physics. It isn't perfect, but it is a useful model!

 

[e2iPi]

Says the guy who started attacking someone for asking questions so that he might be come more educated and less ignorant in a most difficult subject of interest :lol:

I apologize for Joe's deplorable behavior. It's embarrassing, at least to me, that a supposed rational person would behave in such a manner.

I was under the impression that LoR believed that people who want to learn should be guided along, not attacked for admitting their own limited knowledge and asking for assistance

By and large we do. Just ignore Joe.

-1

 

[ImprobableJoe]

Why? Why does a bend in gravity result in the acceleration of matter? I already stated that the 'ruber sheet' model is flawed, as the objects on the sheet are drawn by Earth's gravity and merely roll down the sheet because it's in the way- a condition not present IRL, as spacetime does not sit above a large mass of matter (if it did, it would merely push the question back one step while not answering anything) and we do not sit atop of and roll around on spacetime, but travel through it.

"Why"? Really? The point is that it DOES. The problem is solved. The equations work out. That's IT.

Maybe we are talking across one another, and if that is true you have a vague sort of excuse, and I forgive you for your earlier rudeness. If you would like us to talk you through math and representative models, you're simply barking up the wrong tree, the same as if you were to question the existence of subatomic particles. You're arguing against a strawman.... a hugely common strawman that you bear no blame in supporting.

 

[ImprobableJoe]

I apologize for Joe's deplorable behavior. It's embarrassing, at least to me, that a supposed rational person would behave in such a manner.

Reported to the Moderators for violation of forum rules.

 

[Zylstra]

"Why"? Really? The point is that it DOES. The problem is solved. The equations work out. That's IT.

Wow, thanks! So, we clearly didn't need Newton or Einstein! It just does! No need to inquire, no point to science, no reason to look for what actually causes things to act as they do! How do birds fly? They just do! How do the planets stay in orbit? They just do! Why do clock slow at great speeds? They just do! Why do the seasons change? They just do! Now all you need to do is add 'because God made it that way' to the end of your argument and you'll have all the answers to everything! :roll:

*turns u[p volume on computer as a Bad Religon comes on*

I forgive you for your earlier rudeness.

:lol:

as if you were to question the existence of subatomic particles

You mean those models we only know about because someone asked a question that led people to question the old models? :roll: Asking questions and never being satisfied with simple, circular, meaningless responses is what fuels scientific progress as well as personal growth and the fight against ignorance. That you hold your ignorance so dear (they just do!) makes you no different than a YEC at the most basic level.

You're arguing against a strawman....

You don't even know what a strawman is! I distorted noone's arguments and never even attempted to challenge anyone's hypothesis, theory, assertion, or position. What I did and continue to do is ask for clarification as to how the current model explains how the distortion of spacetime around matter results in the acceleration of bodies so that they approach one another'* . 'It just does'
is not an answer, it's giving up.

So, if you're going to interject in my thread, either contribute to the discussion at hand pr at least try to make yourself look less like an uneducated and ignorant anal-retentive jerm Otherwise, i thank you in advance for excusing yuourself from the discussion.

* the mathematical description of the event aside, are there any theories regarding how this actually brings about the acceleration of the bodies in the first place?

 

[Master_Ghost_Knight]

* the mathematical description of the event aside, are there any theories regarding how this actually brings about the acceleration of the bodies in the first place?

Well generally using math is the only way we have to quantify the event and tell the limits of how it happens in order to say what really happens.

But in a generic description earlier hypotesis sugested that gravity has an associated particle (graviton) that travels the distance to meet a body in space and transfer a momentum (pulling it) if one assumes that they radiated uniformely that would explain the inverse squared to the distance relation (and must be about the inverse square relation with some local fluctuation and not anything else), this has particularly interesting results (that requiers the notion of mathematics such as fields and fluxes, so I will leave it there). Other models sugest that it is actually the configuration of space that it is changed by the presence of mass/energy, and in that case the decay of gravity depends on how mass/energy distorts space, it may also be that they do in a inverse square to the distance but it may also have other configurations more or less further away from the inverse square relation (there you go math again).
There may be other models but this ones are the most popular (can you guess who they are?).

 

[SchrodingersFinch]

Everyone stay on topic!

 

[aeroeng314]

You don't even know what a strawman is! I distorted noone's arguments and never even attempted to challenge anyone's hypothesis, theory, assertion, or position. What I did and continue to do is ask for clarification as to how the current model explains how the distortion of spacetime around matter results in the acceleration of bodies so that they approach one another'*

To give another example to help clarify this even more (in addition to those explanations you've already received), consider the following example.

Imagine that you and a friend are standing on a sphere and decide to walk off in two different directions. In fact, you head off perpendicular to one another. You both agree to walk in a perfectly straight line (and we'll assume that you're capable of doing that). After walking for some time, you both meet up again in a different spot, even though you started walking in different directions and never change direction. This is how curvature of a space (in this case the 2D space that's the surface of the sphere) can affect the path of a particle. As mentioned earlier, particles move along geodesics. On a sphere (which has a positive Gaussian curvature), the geodesics will be "attracted" to one another.

This is a very simple example, but it's only meant to illustrate how the curvature of space affects paths.

 

[Zylstra]

Well generally using math is the only way we have to quantify the event and tell the limits of how it happens in order to say what really happens.

But in a generic description earlier hypotesis sugested that gravity has an associated particle (graviton) that travels the distance to meet a body in space and transfer a momentum (pulling it) if one assumes that they radiated uniformely that would explain the inverse squared to the distance relation (and must be about the inverse square relation with some local fluctuation and not anything else), this has particularly interesting results (that requiers the notion of mathematics such as fields and fluxes, so I will leave it there)

An apparent problem I see with the theory of the graviton is that , if we have three objects



A................ ................ B ................................ C


My understanding is that A's gravitational 'pull' on C is not diminished by B being in the way, as we would expect if gravitons were passing between them (with some being stopped as each interacts with B). Rather, the effects of A and C seem to remain the same,with B's interactions with both added to them. This seems to support the warping spacetime, rather than the passing of force carrying particles between the objects. If I am wrong on this, do correct me.


Edited in red

 

[Master_Ghost_Knight]

An apparent problem I see with the theory of the graviton is that , if we have three objects



A................ ................ B ................................ C


My understanding is that A's gravitational 'pull' on C is not diminished by B being in the way, as we would expect if gravitons were passing between them (with some being stopped as each interacts with B). Rather, the effects of A and C seem to remain the same,with B's interactions with both added to them. This seems to support the warping spacetime, rather than the passing of energy carrying particles between the objects. If I am wrong on this, do correct me.

Yes and No. Gravity apears to respect the additive rule (the effect of A and B on C is the effect of A on C plus the effect of B on C), same does happen whit electromagnetic force, but electromagnetic force we do know that the information is carried by photons. It is true that dielectric matterials does change the configuration of the electromagnetic field and tha gravity doesn't really have a cunter part to that, but none of the less the result is the same. But yet again Gravity isn't really currenty better described by the relativistic means while electromagnetics (even tough it could fall on something similar) is explained in a diffrent light.
The subject is more complicated then it appears on the surface, the problem isn't really intuitive, and trying to use what we intuitively would think about it we would inevitably findout that we are mistaken.

Baby steps, there are other things first.

 

[Zylstra]

Thanks for the info, Ghost. I'll ask the local library whether they can get the books you mentioned on loan