control Posted January 12, 2006 Share Posted January 12, 2006 in the 2D model of space/time, a key feature to explain gravity is that mass "warps" the fabric by existing. The fabric is thought of as a rubber sheet, and mass makes the sheet become concave, letting other masses roll down towards the larger mass. However, everyone seems to not notice that for this effect to happen there would have to be GRAVITY for the actual masses to move down and distort the sheet. This model does not explain gravity at all, and should not be used. If this model is a literal explanation of how gravity works, then relativity has it all wrong about gravity. Link to comment Share on other sites More sharing options...
insane_alien Posted January 12, 2006 Share Posted January 12, 2006 The fabric is thought of as a rubber sheet, and mass makes the sheet become concave, letting other masses roll down towards the larger mass. This is merely an analogy to what it is like. The "fabric" can be thought of a being a representation of the gravitational potential energy throughout the "space". since most systems prefer to have as little potential energy as possible they move "down" the gravitational well and gain velocity. It is wise to not take analogies as a literal representation of a theory. It is merely describing something in laymans terms. Link to comment Share on other sites More sharing options...
control Posted January 12, 2006 Author Share Posted January 12, 2006 I did know about not taking models literally, it's just that it shouldn't be explained with the other gravity being there. But I suppose you need the model as a stage towards understanding the real thing. Can gravity not be the attraction between everything that has a difference in charge? (if neutron stars are thought of as being like a single large particle formed by lots of mass crushing together and neutralising itself and then not being able to repel or attract further). Link to comment Share on other sites More sharing options...
□h=-16πT Posted January 12, 2006 Share Posted January 12, 2006 in the 2D model of space/time, a key feature to explain gravity is that mass "warps" the fabric by existing. The fabric is thought of as a rubber sheet, and mass makes the sheet become concave, letting other masses roll down towards the larger mass. However, everyone seems to not notice that for this effect to happen there would have to be GRAVITY for the actual masses to move down and distort the sheet. This model does not explain gravity at all, and should not be used. If this model is a literal explanation of how gravity works, then relativity has it all wrong about gravity. That's an analogy. It's easier than writing [math]G^{\alpha \beta}=8\pi T^{\alpha \beta}[/math] on the board and confusing everyone. Link to comment Share on other sites More sharing options...
patcalhoun Posted January 12, 2006 Share Posted January 12, 2006 in the 2D model of space/time, a key feature to explain gravity is that mass "warps" the fabric by existing. Whenever you place a key term of an analogy in quotes, you're off to a bad start. The fabric is thought of as a rubber sheet, and mass makes the sheet become concave, letting other masses roll down towards the larger mass. However, everyone seems to not notice that for this effect to happen there would have to be GRAVITY for the actual masses to move down and distort the sheet. This model does not explain gravity at all, and should not be used. If this model is a literal explanation of how gravity works, then relativity has it all wrong about gravity. This has more to do with taking an analogy too far rather than the underlying point. Einstein's equations simply state the curvature of the space-time is the direct consequence of some configuration of matter which it contains; this curvature is what we call gravity. Link to comment Share on other sites More sharing options...
amrit Posted February 7, 2006 Share Posted February 7, 2006 Control: in the 2D model of space/time, a key feature to explain gravity is that mass "warps" the fabric by existing. The fabric is thought of as a rubber sheet, and mass makes the sheet become concave, letting other masses roll down towards the larger mass. However, everyone seems to not notice that for this effect to happen there would have to be GRAVITY for the actual masses to move down and distort the sheet. This model does not explain gravity at all, and should not be used. If this model is a literal explanation of how gravity works, then relativity has it all wrong about gravity. Amrit: According to my research cosmic space is curve because of the round distibution of quanta of space. The idea that space could have a granular structure has about 15 years. Space should be build up out of quanta of space (QS) of the size of Planck. When I came across this idea, it came to my mind that granular structure of space is deeply related with its geometry, lets The idea that space could have a granular structure has about 15 years. Space should be build up out of quanta of space (QS) of the size of Planck. When I came across this idea, it came to my mind that granular structure of space is deeply related with its geometry, lets say with the curvedness of space. More space is curved, more space is dense. Round distribution of QS around the mass is making space round. I was thinking for a long time how to put this idea in math form and one beautiful day it came into my mind: density of space D is in relation with mass m according to the formula: D = m x G D is density of the object its centre M is a mass of the object G here is gravitational constant. In every formula of physics m can be changed with D/G. Formula for gravitational force Fg between two objects, r is the distance between the centre of the objects Fg = (D1 x D2) (r square x G) Formula for gravitational acceleration g, where r is the radius of the planet (star) g = D/ r on square ……all other formula can be develop in this way They show clearly that Fg, a, time dilatation, kinetic energy, light bending ……..depends on the density of space D it seems that gravitational waves (GW) are a pure math speculation. This is the statement of Prof. Loinger from Milan. See more: http://forum.physorg.com/index.php?showtopic=4321 Link to comment Share on other sites More sharing options...
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