Mordred Posted December 30, 2017 Share Posted December 30, 2017 No worries, the added details on intrinsic to what I have will help Link to comment Share on other sites More sharing options...
Unified Field Posted December 30, 2017 Author Share Posted December 30, 2017 (edited) Quote Unified Field: how much of standard physics do you accept? Do you accept Newton's laws? Newtonian gravity (as a nonrelativistic approximation)? Yes, except the part, which tells, that gravity is oriented towards the center of mass - it won't work, if you're inside a hollow sphere... In an object, which is made of an uniform material, mass is distributed equally, if there's no influence of an external g. field (at least in a sphere)... If there would be a planetary body, made of liquid water and nothing else, there shouldn't be no pressure towards the center... Edited December 30, 2017 by Unified Field Link to comment Share on other sites More sharing options...
Mordred Posted December 30, 2017 Share Posted December 30, 2017 (edited) 14 minutes ago, Unified Field said: Ok, but it is also a source of force directed towards it. Outside the g. field of Earth this force can be measured. If every particle of matter is a source of this force, then it's obvious, that the larger is the number of particles in a specified area, the stronger is the force... Not exactly, its the distribution of those particles that matter. This is part of the Shell theorem which is going to be tricky to explain at the moment till we get you straightened on basic kinematics. Lets put it this way if I have a uniform distribution of particles then there is no net sum of force in any direction. So if I have a space time field of uniform distribution there is no inherent motion in any direction. We can arbitrarily choose any COM in this type of field. Same would apply to an electromagnetic field. It is the potential difference (voltage) that leads to current flow. In you OP you have a fixed number of particles that comprise the Sun for example. Simply changing the density via volume change does not change the number of particles which relate to G (in the electromagnetic field Coulombs law). However you can change the particle number density in a finite volume to increase density but this is equivalent to increasing the mass term. two different scenarios of altering density. the first does not increase particle number while the latter does. We can alter density one other way and that is via temperature change. Now if you apply the ideal gas laws you can see that density isn't nearly as appropriate as mass via resistance to inertia change, which is the physics definition. https://www.britannica.com/science/Coulombs-law Edited December 30, 2017 by Mordred Link to comment Share on other sites More sharing options...
uncool Posted December 30, 2017 Share Posted December 30, 2017 (edited) 11 minutes ago, Unified Field said: Yes, except the part, which tells, that gravity is oriented towards the center of mass - it won't work, if you're inside a hollow sphere... In an object, which is made of an uniform material, mass is distributed equally (at least in a sphere)... Two things. 1) There is no part that says that; it isn't even true in general. More specifically: there are systems of objects where one object is not attracted towards the center of mass, but instead towards a nearby mass. This is clearest, for example, in the Sun-Earth-Moon system; the moon is attracted to the Earth, not to the center of mass of the Earth and Sun. 2) In the case of an object being attracted to a massive (that is, having mass) sphere, that in't separate from Newtonian gravity. It's a direct consequence (via the shell theorem, as Mordred says). As such, do you reject Newtonian gravity? Edited December 30, 2017 by uncool Link to comment Share on other sites More sharing options...
Unified Field Posted December 30, 2017 Author Share Posted December 30, 2017 (edited) 13 minutes ago, Mordred said: Not exactly, its the distribution of those particles that matter. This is part of the Shell theorem which is going to be tricky to explain at the moment till we get you straightened on basic kinematics. Lets put it this way if I have a uniform distribution of particles then there is no net sum of force in any direction. So if I have a space time field of uniform distribution there is no inherent motion in any direction. We can arbitrarily choose any COM in this type of field. Same would apply to an electromagnetic field. It is the potential difference (voltage) that leads to current flow. In you OP you have a fixed number of particles that comprise the Sun for example. Simply changing the density via volume change does not change the number of particles which relate to G (in the electromagnetic field Coulombs law).. However you can change the particle number density in a finite volume to increase density but this is equivalent to increasing the mass term two different scenarios of altering density. the first does not increase particle number while the latter does. We can alter desnity one other way and that is via temperature change. https://www.britannica.com/science/Coulombs-law Yes, its the distribution of those particles that matter. But also their atomic mass - atom of lead has much more mass and is much densier, than hydrogen. Quote Lets put it this way if I have a uniform distribution of particles then there is no net sum of force in any direction. Exactly! And this is why I said this: "If there would be a planetary body, made of liquid water and nothing else, there shouldn't be no pressure towards the center...". Motion and force appear, when there's a differential of any kind - as in nature every difference wants to be nullified. Quote However you can change the particle number density in a finite volume to increase density but this is equivalent to increasing the mass term You can as well change the volume and for example compress the particles over smaller space - but it will work only in the case of gases (possibly plasma?). It would be rather hard, if not impossible to compress a rocky planet. You can as well change the energy level of particles, what affects the state of matter and it's distribution, without affecting the mass. Edited December 30, 2017 by Unified Field Link to comment Share on other sites More sharing options...
uncool Posted December 30, 2017 Share Posted December 30, 2017 3 hours ago, Unified Field said: I think, that density of an object has significant importance for the properties of g. field, which it produces. What makes me thinks this way? Well, I've noticed, that celestial objects, which have low density, like a nebula, don't attract other objects with the same force, as planets or stars. What, precisely, do you mean by this? I think this is central to your claims. Link to comment Share on other sites More sharing options...
Mordred Posted December 30, 2017 Share Posted December 30, 2017 (edited) No your missing the point. Your equating this to density but its the distribution itself that is important. You can have an incredibly dense field that is uniform that has no inherent direction of force. Take a plasma gas and just increase the temperature. You decrease the density. Now cool it down the density increases Doesn't mean you develop a greater attraction to a COM. Edited December 30, 2017 by Mordred Link to comment Share on other sites More sharing options...
Unified Field Posted December 30, 2017 Author Share Posted December 30, 2017 Simply changing the density via volume change does not change the number of particles which relate to G (in the electromagnetic field Coulombs law).. If electrostatic charge depends on the concentration of charged particles, then why gravity shouldn't? If I would want to reach Earth's core with a projectile, I would concentrate as much mass, as I can, in the smallest possible space. If I would get 10000 tonnes concentrated in a small marble and dropped it on Earth's surface, it could possibly reach the center of planet - but the bigger would be the size, the more force I would need to get through the crust... 9 minutes ago, uncool said: What, precisely, do you mean by this? I think this is central to your claims. Did you ever heard about stars or planets, which are orbiting around clouds of interstellar gas? In which direction the attraction is stronger - of a planet towards the cloud, or cloud towards the planet? I would choose the secon option, even if the cloud would have bigger mass, than planet... Link to comment Share on other sites More sharing options...
Mordred Posted December 30, 2017 Share Posted December 30, 2017 (edited) No your still missing the point its a matter of using the proper terminology. Density isn't appropriate because you can change density without changing the force of attraction. Mass as resistance to inertia change is the appropriate term via f-ma ( you cannot ignore this by finding appropriate situation. A definition must follow all potential situations). Simply ignoring the fact that temperature can increase and decrease the density of a field of plasma without causing a stronger force of attraction isn't appropriate. Newtons basic laws of inertia. this is why both uncool and I mentioned the Shell theorem as its directly applicable. Edited December 30, 2017 by Mordred Link to comment Share on other sites More sharing options...
Unified Field Posted December 30, 2017 Author Share Posted December 30, 2017 12 minutes ago, Mordred said: No your missing the point. Your equating this to density but its the distribution itself that is important. You can have an incredibly dense field that is uniform that has no inherent direction of force. Take a plasma gas and just increase the temperature. You decrease the density. Now cool it down the density increases Doesn't mean you develop a greater attraction to a COM. Not in it's inside - particles inside an uniform object (or a medium) don't experience any attraction, no matter, what is their state. But their concentration (or state) will affect the force, with which other bodies will be attracted. If we turn the Sun into a nebula (keeping it's mass), particles within the cloud won't experience any gravity, but it will affect the attraction of all the planets in Solar System... Link to comment Share on other sites More sharing options...
Mordred Posted December 30, 2017 Share Posted December 30, 2017 Ignoring what I stated isn't going to change anything. You can change density without changing the force of attraction. Its as simple as that... Link to comment Share on other sites More sharing options...
Unified Field Posted December 30, 2017 Author Share Posted December 30, 2017 Quote Your equating this to density but its the distribution itself that is important But distribution of mass in space IS the density. Link to comment Share on other sites More sharing options...
uncool Posted December 30, 2017 Share Posted December 30, 2017 8 minutes ago, Unified Field said: Did you ever heard about stars or planets, which are orbiting around clouds of interstellar gas? In which direction the attraction is stronger - of a planet towards the cloud, or cloud towards the planet? I would choose the secon option, even if the cloud would have bigger mass, than planet... The forces are, by Newton's third law, equal (and opposite). The accelerations are inversely proportional to the mass, by Newton's second law - so, as an interstellar cloud will generally be more massive than a planet, the planet's movement will be more affected. If you believe otherwise, then you are rejecting Newton's laws. Let's take interstellar gas out of the picture for a moment (as that runs into definition issues - interstellar literally means "between stars"). Instead, let' focus on galaxies. Yes, I have heard of stars orbiting galaxies (or, more precisely, orbiting as part of a galaxy). The closest thing to your statement is that, say, the acceleration of the Earth is more affected by the Sun than by the galaxy. Is that what you are trying to talk about? Link to comment Share on other sites More sharing options...
Unified Field Posted December 30, 2017 Author Share Posted December 30, 2017 Quote You can change density without changing the force of attraction. Its as simple as that... It depends on the medium. Turning ice into water vapor won't change the attraction on the moon (possibly?), but it will have significant meaning within an atmosphere. Link to comment Share on other sites More sharing options...
Mordred Posted December 30, 2017 Share Posted December 30, 2017 (edited) You need to look at the sum of forces. If your at the precise center of the Earth the force of attraction is zero as your surrounded by equal matter on all facings. Its the blooming distribution. Edited December 30, 2017 by Mordred Link to comment Share on other sites More sharing options...
Strange Posted December 30, 2017 Share Posted December 30, 2017 3 hours ago, Unified Field said: First I need to figure out something to measure the inward force - I don't own a laboratory. Then I can calculate, how this force differs, depending on the size of central object... A spring balance. But you will need to be careful about friction. (Taking care of confounding factors like that is an important part of experimental design.) 3 hours ago, Unified Field said: But still the same equations are being used in both cases... Nope. 3 hours ago, Unified Field said: Yes. But it doesn't mean, that 4D won't behave in similar way... If that were true, you could use a 4D sheet ... 2 hours ago, Unified Field said: And this is, what makes me wonder - how it's possible, that no one didn't think about it. I mean, it's something rather obvious, that a force behaves differently, when it's concentrated in a single point and when it's distributed over some area. They did think about it. Newton has a very famous proof that you are wrong. https://en.wikipedia.org/wiki/Shell_theorem Basically, it makes no difference if the mass is spread out every throughout a sphere, forms a then shell at the surface or is concentrated at the centre. 3 hours ago, Unified Field said: I don't need the exact values, only the ratio, how much stronger should be the force, when mass of central body is 2 times so high. You know this from Newton's law of gravitation, right? 3 hours ago, Unified Field said: I think, that the best would be to measure all 4 scenarios twice - for close and distant locations of attracted body. And this, of course. No? 2 hours ago, Unified Field said: Inside the object, there's no attraction towards the center and matter is "floating" freely. You have never seen people in coal mines? There seems to be gravity there, just like on the surface. Link to comment Share on other sites More sharing options...
studiot Posted December 30, 2017 Share Posted December 30, 2017 2 hours ago, Mordred said: This includes tensors which is a functional of a vector. I'm sorry? Link to comment Share on other sites More sharing options...
Unified Field Posted December 30, 2017 Author Share Posted December 30, 2017 (edited) 14 minutes ago, uncool said: The forces are, by Newton's third law, equal (and opposite). The accelerations are inversely proportional to the mass, by Newton's second law - so, as an interstellar cloud will generally be more massive than a planet, the planet's movement will be more affected. If you believe otherwise, then you are rejecting Newton's laws. Newton laws work with solid bodies. In the case of liquids and gases, we use different rules... Cloud of gas is a body, but can you push it as a single object with your hand? Quote Let's take interstellar gas out of the picture for a moment (as that runs into definition issues - interstellar literally means "between stars"). Instead, let' focus on galaxies. Yes, I have heard of stars orbiting galaxies (or, more precisely, orbiting as part of a galaxy). The closest thing to your statement is that, say, the acceleration of the Earth is more affected by the Sun than by the galaxy. Is that what you are trying to talk about? Yes - if entire Solar System is attracted towards the galaxy center, then why planets are attracted towards the Sun and not towards the galaxy? Or how galaxies interact with eachother as single objects and not as separate star systems? It's the SIZE of a field, which matters... Edited December 30, 2017 by Unified Field Link to comment Share on other sites More sharing options...
Strange Posted December 30, 2017 Share Posted December 30, 2017 4 hours ago, Unified Field said: I think, that density of an object has significant importance for the properties of g. field, which it produces. If you were correct, then Newton's equation for gravity, which doesn't include density, would give wrong (or consistent) results. As it works for the moons of all the different planets (with their varying densities) this implies that the density factor is not needed. Can you explain why that is? You seem to be substituting "common sense" for scientific rigour. The scientific method is designed to stop thinks like intuition and common sense getting in the way of results. You are also confusing things by introducing things like stopping a bullet/beachball or firing a projectile into the Earth, where shape, surface area, friction, rigidity, air resistance and all sorts of other factors come into play. Most of these have nothing to do with your central hypothesis. Link to comment Share on other sites More sharing options...
Mordred Posted December 30, 2017 Share Posted December 30, 2017 (edited) 30 minutes ago, studiot said: I'm sorry? see here for example "A tensor is a particular type of function." http://www.physics.miami.edu/~nearing/mathmethods/tensors.pdf second example Roughly speaking, the metric tensor is a function http://mathworld.wolfram.com/MetricTensor.html every tensor will have associated functions A mixed can have several "In mathematics, the modern component-free approach to the theory of a tensor views a tensor as an abstract object, expressing some definite type of multi-linear concept " any multilinear concept has a function. https://en.wikipedia.org/wiki/Tensor_(intrinsic_definition) Though I should be more specific a rank 1 tensor is a set of vector functionals Edited December 30, 2017 by Mordred Link to comment Share on other sites More sharing options...
uncool Posted December 30, 2017 Share Posted December 30, 2017 1 minute ago, Unified Field said: Newton laws work with solid bodies. In the case of liquids and gases, we use different rules... No. Newton's laws are still accurate for liquids and gases; the only difference is that they have to be analyzed through densities (note: not necessarily mass densities). The laws are still accurate. 3 minutes ago, Unified Field said: Yes - if entire Solar System is attracted towards the galaxy center, then why planets are attracted towards the Sun and not towards the galaxy? Or how galaxies interact with eachother as single object and as separate star systems? Because the sun is much, much, much, much closer than anything else in the galaxy. It's not because the Sun is more dense. It's that everything else is really, really, stupendously far away - so Newton's law of gravitation says that the corresponding force is tiny compared to that of the Sun. Link to comment Share on other sites More sharing options...
Unified Field Posted December 30, 2017 Author Share Posted December 30, 2017 (edited) Quote A spring balance. But you will need to be careful about friction. (Taking care of confounding factors like that is an important part of experimental design.) That's what I was thinking about - it just has to be rather precise... Quote Nope. Poisson's equations are being used in both cases... Quote If that were true, you could use a 4D sheet ... If you have one, I will buy it... "Similar" doesn't mean "exactly the same" - it means, that they just have some things in common... Quote You know this from Newton's law of gravitation, right? Newton's law of gravitation works nicely on Earth - but how it works beyond the g. field of Earth? Quote You have never seen people in coal mines? There seems to be gravity there, just like on the surface. Because there's a lot of concentrated mass below them....? Edited December 30, 2017 by Unified Field Link to comment Share on other sites More sharing options...
Mordred Posted December 30, 2017 Share Posted December 30, 2017 (edited) mass below and mass above. Is the force of G less or greater than at sea level ? I will leave you with that thought experiment (google shell theorem to answer correctly) https://en.m.wikipedia.org/wiki/Shell_theorem Has the important equations Edited December 30, 2017 by Mordred Link to comment Share on other sites More sharing options...
Unified Field Posted December 30, 2017 Author Share Posted December 30, 2017 They did think about it. Newton has a very famous proof that you are wrong. https://en.wikipedia.org/wiki/Shell_theorem Basically, it makes no difference if the mass is spread out every throughout a sphere, forms a then shell at the surface or is concentrated at the centre. It doesn't matter for the bodies attracted from the outside If the body is a spherically symmetric shell (i.e., a hollow ball), no net gravitational force is exerted by the shell on any object inside, regardless of the object's location within the shell. Inside, there's no attraction towards the center. Actually this confirms, what I said... Thanks I would only add one thing - there will be attraction towards the center inside a hollow sphere, if we put there an object with bigger mass, than the entire sphere and with bigger density - only then, the hollow sphere will be attracted stronger towards this object, than the other way... 14 minutes ago, Mordred said: mass below and mass above. Is the force of G less or greater than at sea level ? I will leave you with that thought experiment (google shell theorem to answer correctly) https://en.m.wikipedia.org/wiki/Shell_theorem Has the important equations That's a nice question I think, that in both directions it will start to weaken and finally disappear completely. I was thinking about it yesterday - what would happen, if we would make a tunnel through the core of Earth? I guess, that at some distance from the center, we would enter a 0-g area. But maybe I'm wrong? Maybe we would start getting heavier, the closer to the center we would move? Link to comment Share on other sites More sharing options...
studiot Posted December 30, 2017 Share Posted December 30, 2017 (edited) 1 hour ago, Mordred said: see here for example "A tensor is a particular type of function." http://www.physics.miami.edu/~nearing/mathmethods/tensors.pdf second example Roughly speaking, the metric tensor is a function http://mathworld.wolfram.com/MetricTensor.html every tensor will have associated functions A mixed can have several "In mathematics, the modern component-free approach to the theory of a tensor views a tensor as an abstract object, expressing some definite type of multi-linear concept " any multilinear concept has a function. https://en.wikipedia.org/wiki/Tensor_(intrinsic_definition) Though I should be more specific a rank 1 tensor is a set of vector functionals Thank you for rewording/expanding that part of your previous post. I read it to mean something quite different, to whit a 'definition' of a functional. A functional is a map from a vector space to the underlying field of that vector space. The space of all functionals of a given vector space is the dual space of the tangent space of that vector space. In the case you are exhibiting the underlying field is R, the real numbers. I don't think you can define or explain what a tensor is in under 10 words. Edited December 30, 2017 by studiot Link to comment Share on other sites More sharing options...
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