Spacetime Causes Gravity

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xmo1

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<p><font size="2">Gravity is the&nbsp;response&nbsp;by a second&nbsp;mass that&nbsp;comes in contact with a bend in spacetime caused by&nbsp;an initial mass. Any takers?</font></p><p><font size="2">Oh, and time. Does time change it's nature in response to being observed as either an instant, or as a continuum, similar to wave particle duality?</font></p> <div class="Discussion_UserSignature"> <p>DenniSys.com</p> </div>
 
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vastbluesky92

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Gravity is the&nbsp;response&nbsp;by a second&nbsp;mass that&nbsp;engages the bend in spacetime caused by&nbsp;an initial mass. Any takers?Oh, and time. Does time change it's nature in response to being observed as either an instant, or as a continuum, similar to wave particle duality? <br /> Posted by xmo1</DIV></p><p>I'm not sure what you mean by "engages the bend." Spacetime is always warped by a body with mass and all a second body does is follow the path of least resistance. </p><p>How do you expirimentaly (or non-expirimentally for that matter) observe time as a continuum? Actually I don't think we can't expirementally observe time at all apart from the apparent arrow of time. Now that I think about it though, I do think I remember some hypotheses (I try to avoid using the word theories superfluously) about some kind of time particles, maybe someone who knows about that? But I'm pretty sure it's commonly accepted as simply another dimension and not any kind of wave or anything. </p> <div class="Discussion_UserSignature"> <p>--____________________________________________--</p><p><font size="1"> Don't be too hard on me...I'm only in PHY 1010 ;)</font></p><p> </p><p><font color="#339966">         The following goes without saying:</font> </p> </div>
 
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derekmcd

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Gravity is the&nbsp;response&nbsp;by a second&nbsp;mass that&nbsp;engages the bend in spacetime caused by&nbsp;an initial mass. Any takers?Oh, and time. Does time change it's nature in response to being observed as either an instant, or as a continuum, similar to wave particle duality? <br /> Posted by xmo1</DIV></p><p>You're about 100 years late.&nbsp; Einstein beat ya to the punch on gravity.&nbsp; Not clear what you mean about time either.&nbsp; Time is reference frame dependent based on the observer.&nbsp; I suppose you could consider events in spacetime to be specific instants dependedd on your reference frame while spacetime as whole is a continuum.&nbsp; Not quite the same as wave-particle duality. </p> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>
 
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xmo1

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I'm not sure what you mean by "engages the bend." Spacetime is always warped by a body with mass and all a second body does is follow the path of least resistance. How do you expirimentaly (or non-expirimentally for that matter) observe time as a continuum? Actually I don't think we can't expirementally observe time at all apart from the apparent arrow of time. Now that I think about it though, I do think I remember some hypotheses (I try to avoid using the word theories superfluously) about some kind of time particles, maybe someone who knows about that? But I'm pretty sure it's commonly accepted as simply another dimension and not any kind of wave or anything. <br />Posted by vastbluesky92</DIV><br /><br />Engage is changed to contact for clarification.</p><p>
Spacetime is always warped by a body with mass and all a second body does is follow the path of least resistance.
</p><p>Yes. So why the discussion about what is gravity?
That's the million dollar question.
</p><p>How&nbsp;is time observed? I think we need to talk about spacetime, which follows the rules.</p> <div class="Discussion_UserSignature"> <p>DenniSys.com</p> </div>
 
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xmo1

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>You're about 100 years late.&nbsp; Einstein beat ya to the punch on gravity.&nbsp; Not clear what you mean about time either.&nbsp; Time is reference frame dependent based on the observer.&nbsp; I suppose you could consider events in spacetime to be specific instants dependedd on your reference frame while spacetime as whole is a continuum.&nbsp; Not quite the same as wave-particle duality. <br />Posted by derekmcd</DIV></p><p>The graphics I've seen set the mass at the center bottom of the spacetime warp. It seems to me though, that things that radiate from a spherical shape do so spherically (in all directions), rather than being limited by a frame or plane. When the observer appears, a dynamic interaction occurs relative to the properties of the two objects. The radiation&nbsp;(radiant vectors) might then fluctuate (in strength,&nbsp;direction etc.).</p><p>Just thinking here: A particle of spacetime would be viewed as the shell surrounding an object. The path of that particle relative to the observer would define the frame of observation.</p><p>So, am I missing some physics?<br /></p> <div class="Discussion_UserSignature"> <p>DenniSys.com</p> </div>
 
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SpeedFreek

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>The graphics I've seen set the mass at the center bottom of the spacetime warp. It seems to me though, that things that radiate from a spherical shape do so spherically (in all directions), rather than being limited by a frame or plane. When the observer appears, a dynamic interaction occurs relative to the properties of the two objects. The radiation&nbsp;(radiant vectors) might then fluctuate (in strength,&nbsp;direction etc.).Just thinking here: A particle of spacetime would be viewed as the shell surrounding an object. The path of that particle relative to the observer would define the frame of observation.So, am I missing some physics? <br /> Posted by xmo1</DIV></p><p>The graphics you have seen are mere two dimensional images depicing the "rubber sheet" analogy, which is a two dimensional analogy of the warping of spacetime. It is very complicated to depict that information in three dimensions as a diagram, which is why, when explaining how space is warped by gravity, the model is often simplified to two dimensions for ease of visualisation. Really the only way to truly understand General Relativity (which is what you are actually talking about) is to do the maths, or to at least understand what the maths tells us.</p><p>The 2D rubber sheet analogy is useful, in the same way that imagining our universe as dots on the <strong>surface</strong> of an expanding balloon is useful. It helps get the point across by reducing the number of dimensions being discussed.</p><p>I'm afraid I don't understand what you mean when you talk of a "particle" of spacetime. It is more usual to "slice" spacetime into layers, and this might be what you are getting at. The way spacetime is observed is frame dependent.</p><p>Are you missing some physics? I think so... have a look at the link below.</p><p>HOW to BECOME a <span class="title"><em>GOOD</em></span> THEORETICAL PHYSICIST</p> <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>
 
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DrRocket

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>...Are you missing some physics? I think so... have a look at the link below.HOW to BECOME a GOOD THEORETICAL PHYSICIST <br />Posted by SpeedFreek</DIV></p><p>&nbsp;That is a GREAT website.&nbsp; Thanks.&nbsp; Theoretical physicists don"t come any better than Gerard t'Hooft.&nbsp; Thanks<br /></p> <div class="Discussion_UserSignature"> </div>
 
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xmo1

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<p>Thank you for the link.</p><p>
I'm afraid I don't understand what you mean when you talk of a "particle" of spacetime. It is more usual to "slice" spacetime into layers, and this might be what you are getting at.
</p><p>When (in this case, gravity) surrounds an object in all directions, wouldn't the object be considered the particle?</p><p>
The way spacetime is observed is frame dependent.
</p><p>There is something fundamentally wrong with math when&nbsp;an irrational number is needed to find the area of a circle, and&nbsp;the answer is never equal to one. What would the newage people say about circles and spheres?</p><p>Is there anything wrong with saying spacetime(gravity)? Is there still a mystery? If there is no longer a mystery, then I would say that particle accelerators have outlived their usefulness.</p> <div class="Discussion_UserSignature"> <p>DenniSys.com</p> </div>
 
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DrRocket

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Thank you for the link.Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I'm afraid I don't understand what you mean when you talk of a "particle" of spacetime. It is more usual to "slice" spacetime into layers, and this might be what you are getting at.[/quote]When (in this case, gravity) surrounds an object in all directions, wouldn't the object be considered the particle?
The way spacetime is observed is frame dependent.
There is something fundamentally wrong with math when&nbsp;an irrational number is needed to find the area of a circle, and&nbsp;the answer is never equal to one. What would the newage people say about circles and spheres?Is there anything wrong with saying spacetime(gravity)? Is there still a mystery? If there is no longer a mystery, then I would say that particle accelerators have outlived their usefulness. <br />Posted by xmo1</DIV></p><p>There is something fundamentally right with mathematics when it can prove that the ratio of the circumference of a circle to its diameter is constant.&nbsp; Not to disillusion you further, but pi is not only irrational it is in fact transcendental.</p><p>I have not idea what you&nbsp;mean when you say the area of a circle is never equal to one.&nbsp; A circle with radius sqrt(1/pi) has area 1.</p><p>There is essentially no relationship between what happens in particle accelerators and gravity.&nbsp; What are you talking about ?</p><p>Who cares what the new age people are babbling about this week?&nbsp; They never make any sense anyway.<br /></p> <div class="Discussion_UserSignature"> </div>
 
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vastbluesky92

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Hah, I see I'm not on the internet enough to keep up before other people make my points for me. Oh well, they did it better than I would've anyway. <div class="Discussion_UserSignature"> <p>--____________________________________________--</p><p><font size="1"> Don't be too hard on me...I'm only in PHY 1010 ;)</font></p><p> </p><p><font color="#339966">         The following goes without saying:</font> </p> </div>
 
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SpeedFreek

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>There is something fundamentally wrong with math when&nbsp;an irrational number is needed to find the area of a circle, and&nbsp;the answer is never equal to one. What would the newage people say about circles and spheres. <br /> Posted by xmo1</DIV></p><p>Pi is a constant, a ratio and a real number. It is only irrational if you try to quantize it into an integer. It seems the universe doesn't work in discrete increments.&nbsp; </p><p>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Is there anything wrong with saying spacetime(gravity)? Is there still a mystery? If there is no longer a mystery, then I would say that particle accelerators have outlived their usefulness. <br /> Posted by xmo1</DIV></p><p>Spacetime is a mathematical description. By what mechanism does the curving of space-time actually influence mass?&nbsp;</p> <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>
 
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xmo1

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Pi is a constant, a ratio and a real number. It is only irrational if you try to quantize it into an integer. It seems the universe doesn't work in discrete increments.&nbsp;&nbsp;Spacetime is a mathematical description. By what mechanism does the curving of space-time actually influence mass?&nbsp; <br />Posted by SpeedFreek</DIV><br /><br />"By what mechanism does the curving of space-time actually influence mass?"</p><p>That is the topic. Spacetime causes gravity. But I am slightly taken aback by "Spacetime is a mathematical description." The bending of light experiments pretty much made it a phenomena in my eyes. Save the chalk.</p><p>My thought went to particles of the smallest masses, and then to the largest masses,&nbsp;all of which are&nbsp;encapsulated by spacetime, and bound to the (limitations) imposed by it.</p><p>As someone said, I make the observation&nbsp;some years after&nbsp;Einstein (did he?), but I've never heard it expressed in that way. Have you?</p> <div class="Discussion_UserSignature"> <p>DenniSys.com</p> </div>
 
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xmo1

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>There is something fundamentally right with mathematics when it can prove that the ratio of the circumference of a circle to its diameter is constant.&nbsp; Not to disillusion you further, but pi is not only irrational it is in fact transcendental.I have not idea what you&nbsp;mean when you say the area of a circle is never equal to one.&nbsp; A circle with radius sqrt(1/pi) has area 1.There is essentially no relationship between what happens in particle accelerators and gravity.&nbsp; What are you talking about ?Who cares what the new age people are babbling about this week?&nbsp; They never make any sense anyway. <br />Posted by DrRocket</DIV><br /><br />"sqrt(1/pi) has area 1" I might side with new age people by saying that if anything should have&nbsp;the&nbsp;value of&nbsp;integer one, that thing should be a sphere. That's all. No big deal. Om.</p><p>"What are you talking about ?"<br />We used to call them atom smashers. The idea was to find the smallest particle, and maybe a&nbsp;particle responsible for gravity. Neither of those goals were achieved. The first probably because if you hit anything with enough force it will break into pieces. The second probably because there is none.</p><p>Here is a nice little article from Cern on the Higgs boson.<br />http://www.exploratorium.edu/origins/cern/ideas/higgs.html</p><p>They are still looking. I say, give up. It's not there.</p> <div class="Discussion_UserSignature"> <p>DenniSys.com</p> </div>
 
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SpeedFreek

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>"By what mechanism does the curving of space-time actually influence mass?"That is the topic. Spacetime causes gravity. But I am slightly taken aback by "Spacetime is a mathematical description." The bending of light experiments pretty much made it a phenomena in my eyes.posted by xmo1</DIV></p><p>What I mean is, we only have a mathematical description of spacetime. We do not know how spacetime does what it does. We do not know how gravity propagates. Stating that space-time causes gravity doesn't help us get any closer to understand the mechanism through which space-time causes gravity. </p> <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>
 
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DrRocket

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Pi is a constant, a ratio and a real number. It is only irrational if you try to quantize it into an integer. It seems the universe doesn't work in discrete increments.&nbsp; Spacetime is a mathematical description. By what mechanism does the curving of space-time actually influence mass?&nbsp; <br />Posted by SpeedFreek</DIV></p><p>You have me confused wiht this one.&nbsp; Pi is an irrational real number, in fact it is transcendental.&nbsp; This has nothing to do with "quantizing" it.&nbsp; In fact I have no idea what you mean by quantizing pi.&nbsp; <br />&nbsp;</p><p>The basic classification of real numbers is:</p><p>Natural numbers -- 1,2,3,4...</p><p>Natural numbers plus zero -- 0,1,2,3,4...</p><p>Integers -- -3,-2,-1,0,1,2,3...</p><p>Rational numbers --- things of the form p/q where p and q are integers</p><p>Algebraic numbers --- roots of polynomials with integer (or equivalently rational) coefficients</p><p>Real numbers --- numbers that can be represented as a position on the line (there is a rigorous, and incredibly boring, way to construct the real numbers using Dediking cuts)</p><p>Each of the above sets are contained in the following set and each is closed under addition, subtraction, multiplication and division by a non-zero member of the set. </p><p>Transcendental numbers are real numbers that are not algebraic.&nbsp; Pi is one such number.</p><p>You can also extend the real numbers to the complex numbers and talk about complex algebraic numbers as well.</p><p>&nbsp;</p><p>Curvature of space-time is the way in which general relativity describes gravity.&nbsp; So the curvature of space-time influences mass in pretty much the same way that gravity influences it in Newton's theory.&nbsp; Of course the effect is a bit different, since the two theories are not identical.&nbsp; </p> <div class="Discussion_UserSignature"> </div>
 
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derekmcd

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Curvature of space-time is the way in which general relativity describes gravity.&nbsp; So the curvature of space-time influences mass in pretty much the same way that gravity influences it in Newton's theory.&nbsp; Of course the effect is a bit different, since the two theories are not identical.&nbsp; <br /> Posted by DrRocket</DIV></p><p>"Matter tells spacetime how to curve, and spacetime tells matter how to move."&nbsp; -&nbsp; John A. Wheeler&nbsp;</p><p>&nbsp;</p><p>Love that quote. <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-laughing.gif" border="0" alt="Laughing" title="Laughing" /> </p> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>
 
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SpeedFreek

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>You have me confused wiht this one.&nbsp; Pi is an irrational real number, in fact it is transcendental.&nbsp; This has nothing to do with "quantizing" it.&nbsp; In fact I have no idea what you mean by quantizing pi.<br /> Posted by DrRocket</DIV></p><p>Don't take me too seriously, Doc, I was simply trying (and failing) to mimic the word "irrational" in in the same sense as I thought xmo1 was using it - <em>"There is something fundamentally wrong with math when&nbsp;an irrational number is needed to find the area of a circle, and&nbsp;the answer is never equal to one."</em></p><p>I used quantize wrongly, of course. All I was trying to say is that the ratio of the circumference to the diameter of a circle is pi, and we call it an irrational number because it cannot be expressed as a simple fraction. When we try to express it as a decimal the decimal places go on forever.. you can get more and more accuracy but never come to a final, discrete solution.</p><p>Does this mean all our mathematics are mere approximations? No, not when you use the symbol for pi in your equations, the inaccuracy (or lack of a full and final solution) only becomes apparent when you <em>express it as a decimal</em>*.</p><p>I should resist the urge to post when I am not 100% sure of my subject.&nbsp;</p><p>&nbsp;</p><p>*(which is the phrase I should have used instead of quantize)</p> <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>
 
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MeteorWayne

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Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Don't take me too seriously, Doc, I was simply trying (and failing) to mimic the word "irrational" in in the same sense as I thought xmo1 was using it - "There is something fundamentally wrong with math when&nbsp;an irrational number is needed to find the area of a circle, and&nbsp;the answer is never equal to one."I used quantize wrongly, of course. All I was trying to say is that the ratio of the circumference to the diameter of a circle is pi, and we call it an irrational number because it cannot be expressed as a simple fraction. When we try to express it as a decimal the decimal places go on forever.. you can get more and more accuracy but never come to a final, discrete solution.Does this mean all our mathematics are mere approximations? No, not when you use the symbol for pi in your equations, the inaccuracy (or lack of a full and final solution) only becomes apparent when you express it as a decimal*.I should resist the urge to post when I am not 100% sure of my subject.&nbsp;&nbsp;*(which is the phrase I should have used instead of quantize) <br />Posted by SpeedFreek</DIV><br /><br />It's only an issue in a base 10 system (i.e.decimal). If it was a base 3.1415926536..... no one would notice :) <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>
 
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derekmcd

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>It's only an issue in a base 10 system (i.e.decimal). If it was a base 3.1415926536..... no one would notice :) <br /> Posted by MeteorWayne</DIV></p><p>The PI song.&nbsp; Maybe it's just me, but I just crack up everytime I hear it.</p><p>http://www.youtube.com/watch?v=RaSCByd0UtM&feature=related</p> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>
 
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xmo1

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>What I mean is, we only have a mathematical description of spacetime. We do not know how spacetime does what it does. We do not know how gravity propagates. Stating that space-time causes gravity doesn't help us get any closer to understand the mechanism through which space-time causes gravity. <br />Posted by SpeedFreek</DIV><br /><br /><conjecture />Baseball on a blanket - golfball orbits baseball. Why, because of the curve in the blanket, and because the blanket is not a flat piece&nbsp;of steel. Each object has a blanket. The threads in the blankets that come in contact with each other provide a path that alters the direction of each object. That is the mechanism. That is the way I think it happens.</conjecture></p><p>The problem is that space-time is invisible. We can't see the blanket, much less the threads in the blanket. It makes more sense to me to believe in the 'force of gravity,' but I'm no longer sure that gravity even exists in the classical sense. Should the affects that the curvature of space-time&nbsp;have -&nbsp;be&nbsp;called a force? I cannot get my head around it, and it remains a&nbsp;mystery to me in that sense.</p> <div class="Discussion_UserSignature"> <p>DenniSys.com</p> </div>
 
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xmo1

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>I'm no longer sure that gravity even exists in the classical sense. Should the affects that the curvature of space-time&nbsp;have -&nbsp;be&nbsp;called a force? I cannot get my head around it, and it remains a&nbsp;mystery to me in that sense. <br />Posted by xmo1</DIV><br /><br />speedfreak: "when explaining how space is warped by gravity"</p><p>re: speedfreak - derekmcd quotes Wheeler "Matter tells spacetime how to curve, and spacetime tells matter how to move"</p><p>I've seen the quote as both matter and mass. I think mass is accurate and proper. Someone please correct me if I'm wrong.</p><p>speedfreak: "What I mean is, we only have a mathematical description of spacetime. We do not know how spacetime does what it does. We do not know how gravity propagates. Stating that space-time causes gravity doesn't help us get any closer to understand the mechanism through which space-time causes gravity."</p><p>Re: speedfreak - Did I accurately define the mechanism by analogy, or not?</p><p>Maybe it is the nature of space-time to warp in the presense of mass. The heavier (with disregard to density) the mass the more deflection of space-time. In that case, gravity, in the classical sense, is not needed at all, and I think we have sufficient evidence to support this idea. So what would we do with the gravity constant that is useful in math? Change it's name for the sake of a clearer understanding of physical events. If it is mass that is causing the warpage of spacetime, then it should be the space-time constant as derived from mass calculations. Does this interfere with current mathematical thinking?</p><p>Is gravity needed in the presence of&nbsp;space-time warpage caused by mass?</p> <div class="Discussion_UserSignature"> <p>DenniSys.com</p> </div>
 
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SpeedFreek

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<p>In that context, it seems to me that gravity <strong>is</strong> still required to describe the effect that mass has on space-time or vice versa. Ok, so mass tells space-time how to curve and space-time tells mass how to move... how is the information communicated between them? How does mass "tell" space-time how to curve? How does space-time "tell" mass how to move? We call the answer gravity and so far have nothing to replace that word with. </p> <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>
 
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xmo1

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>In that context, it seems to me that gravity is still required to describe the effect that mass has on space-time or vice versa. Ok, so mass tells space-time how to curve and space-time tells mass how to move... how is the information communicated between them? How does mass "tell" space-time how to curve? How does space-time "tell" mass how to move? We call the answer gravity and so far have nothing to replace that word with. <br />Posted by SpeedFreek</DIV><br /><br />Using the blanket or rubber sheet analogy: Drop the ball on the blanket, and it bends. Any other round object dropped on the blanket will&nbsp;use that bend. Nothing has to be told really. The motion follows the path of least resistance, as someone already said in this thread. The mass causes spacetime to bend.</p><p>I don't think the idea of mass talking to spacetime is valid, because I don't think it needs to in this case.</p><p>I'm aware of the 3d nature of the problem, but I'll be honest, I just don't remember the 4d aspects (math). Hope this thread isn't going in the tank. I would really like to get more feedback.</p> <div class="Discussion_UserSignature"> <p>DenniSys.com</p> </div>
 
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derekmcd

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Using the blanket or rubber sheet analogy: Drop the ball on the blanket, and it bends. Any other round object dropped on the blanket will&nbsp;use that bend. Nothing has to be told really. The motion follows the path of least resistance, as someone already said in this thread. The mass causes spacetime to bend.I don't think the idea of mass talking to spacetime is valid, because I don't think it needs to in this case.I'm aware of the 3d nature of the problem, but I'll be honest, I just don't remember the 4d aspects (math). Hope this thread isn't going in the tank. I would really like to get more feedback. <br /> Posted by xmo1</DIV></p><p>You are over emphasizing the analogies and trying to picture gravity in your mind.&nbsp;&nbsp; General Relativity is just a geometric description of gravity.&nbsp; GR considers gravity as a pseudo force.&nbsp; Object within the gravity well of another object follow a geodesic path (not path of least resistance).&nbsp; A geodesic path is a straight line in curved space.</p><p>It seems like you already understand this, but are just trying to overthink it and apply new terms to what is already known.&nbsp;</p> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>
 
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SpeedFreek

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Using the blanket or rubber sheet analogy: Drop the ball on the blanket, and it bends. Any other round object dropped on the blanket will&nbsp;use that bend. Nothing has to be told really. The motion follows the path of least resistance, as someone already said in this thread. The mass causes spacetime to bend.I don't think the idea of mass talking to spacetime is valid, because I don't think it needs to in this case.I'm aware of the 3d nature of the problem, but I'll be honest, I just don't remember the 4d aspects (math). Hope this thread isn't going in the tank. I would really like to get more feedback. <br /> Posted by xmo1</DIV></p><p>When you drop the ball on the blanket, what is it about the ball that bends the blanket? If you were in zero gravity, would the blanket be bent by the ball?<br /> </p> <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>
 
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