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Gravity Creation Idea (don't assume troll)
There's an idea that's been going through my head dealing with creating
artificial gravity, before you think troll just stay with me here. It deals with two of Einstein's papers; the first stating as an object speed accelerates closer towards the speed of light, it's mass increases, the second states mass is directly related to gravity. So Take an object like a large super-conductive disk, inside a vacuum to reduce friction, and spin it. If you can make it spin fast enough (up towards the speed of light) you should be able to create gravity with out having the real mass required. Creating a sort of virtual mass so to speak. I realize there must be something wrong with my logic because this seems like such a simple solution, so I invite some criticism here. -- Matthew Hagston Hungates Creative Toys and Hobbies ........ http://www.hungates.com |
#2
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Matthew Hagston wrote:
If you can make it spin fast enough (up towards the speed of light) you should be able to create gravity with out having the real mass required. Creating a sort of virtual mass so to speak. I realize there must be something wrong with my logic because this seemslike such a simple solution, so I invite some criticism here. It would work, but there are certain engineering difficulties associated with spinning a material disk fast enough that the apparent mass per unit area would be large enough. Also, there would be a gravity gradient from middle to rim that might be troublesome. Also also, you really wouldn't want to have an accident with the thing. Maybe what you need is a *very* high-current, high-energy cyclotron. You wouldn't want to have an accident with that either. |
#3
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Matthew Hagston wrote:
There's an idea that's been going through my head dealing with creating artificial gravity, before you think troll just stay with me here. It deals with two of Einstein's papers; the first stating as an object speed accelerates closer towards the speed of light, it's mass increases, the second states mass is directly related to gravity. So Take an object like a large super-conductive disk, inside a vacuum to reduce friction, and spin it. If you can make it spin fast enough (up towards the speed of light) you should be able to create gravity with out having the real mass required. Creating a sort of virtual mass so to speak. I realize there must be something wrong with my logic because this seems like such a simple solution, so I invite some criticism here. It would work, to a degree depending on the strength of the disk, but you gain nothing. Remember E=mc^2, mass and energy are two sides of the same coin. When you create a "mass-energy" in a rapidly spinning disk that mass is no different than any other mass. Moreover, the energy you use to spin up the disk is no different than any other mass. In order to spin up a disk fast enough to increase it's mass by, say, 1kg, you need to input 1kg of mass/energy, period. Using your method that would require harnessing 1kg of energy, 90 petajoules!, transporting it to the vicinity of the disk, and then applying the energy to spin up the disk. It would be quite a lot more direct to simply transport a 1kg mass, as the result is exactly the same without the inefficiencies and incredible difficulties. Additionally, to generate 1 gee of gravity through this method would require a mass/energy on the order of that of the Earth. |
#4
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Matthew Hagston ) wrote:
: There's an idea that's been going through my head dealing with creating : artificial gravity, before you think troll just stay with me here. It deals : with two of Einstein's papers; the first stating as an object speed : accelerates closer towards the speed of light, it's mass increases, the : second states mass is directly related to gravity. So Take an object like a : large super-conductive disk, inside a vacuum to reduce friction, and spin : it. If you can make it spin fast enough (up towards the speed of light) you : should be able to create gravity with out having the real mass required. : Creating a sort of virtual mass so to speak. : I realize there must be something wrong with my logic because this seems : like such a simple solution, so I invite some criticism here. I'm no physicist, but don't molecules have trouble staying together in cyclotron-like environments? IOW, everything to date that we can manage accelerate is of a sub-molecular level. What good is creating gravity for elements with no way of retaining any molecular form? And your object, the super-conductive disk; where can I buy one? Eric : -- : Matthew Hagston : Hungates Creative Toys and Hobbies : ........ http://www.hungates.com |
#5
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In article ,
Christopher M. Jones wrote: ...Additionally, to generate 1 gee of gravity through this method would require a mass/energy on the order of that of the Earth. No, only if you insist on having 1G at a distance of some 6400km. At one-millionth the distance, you need one-trillionth (10^-12) the mass. Still kind of a lot, mind you... -- "Think outside the box -- the box isn't our friend." | Henry Spencer -- George Herbert | |
#6
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"Matthew Hagston" wrote in
nk.net: There's an idea that's been going through my head dealing with creating artificial gravity, before you think troll just stay with me here. It deals with two of Einstein's papers; the first stating as an object speed accelerates closer towards the speed of light, it's mass increases, the second states mass is directly related to gravity. So Take an object like a large super-conductive disk, inside a vacuum to reduce friction, and spin it. If you can make it spin fast enough (up towards the speed of light) you should be able to create gravity with out having the real mass required. Creating a sort of virtual mass so to speak. I realize there must be something wrong with my logic because this seems like such a simple solution, so I invite some criticism here. I'm afriad the disk would fly apart due to overwhelming centripital forces far before anything relavistic was achieved. There just aren't materials with that kind of tensile strength :-( Tom |
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Henry Spencer wrote:
In article , Christopher M. Jones wrote: ...Additionally, to generate 1 gee of gravity through this method would require a mass/energy on the order of that of the Earth. No, only if you insist on having 1G at a distance of some 6400km. At one-millionth the distance, you need one-trillionth (10^-12) the mass. Still kind of a lot, mind you... I already thought of that. The problem is one of density. Realistically, you can't get convenient chunks of matter that are denser than about 18 g/cm^3 (e.g. Uranium). This is not all that much more than the average density of Earth (about 5 g/cm^3). Disregarding compression, to achieve 9.8 m/s^2 of gravity on the surface you would need a spherical mass approximately 1,948 km in radius, weighing about half a billion trillion tonnes (5.6e23 kg). Certainly that's a factor of ten off the mass of the Earth, but it's still a tad much. You could get away with a lot less mass if you had extremely dense materials (neutronium, strange matter), but being able to build structures using such materials is speculative at this point. |
#8
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"Christopher M. Jones" wrote in message ... Henry Spencer wrote: In article , Christopher M. Jones wrote: ...Additionally, to generate 1 gee of gravity through this method would require a mass/energy on the order of that of the Earth. No, only if you insist on having 1G at a distance of some 6400km. At one-millionth the distance, you need one-trillionth (10^-12) the mass. Still kind of a lot, mind you... I already thought of that. The problem is one of density. Realistically, you can't get convenient chunks of matter that are denser than about 18 g/cm^3 (e.g. Uranium). This is not all that much more than the average density of Earth (about 5 g/cm^3). Disregarding compression, to achieve 9.8 m/s^2 of gravity on the surface you would need a spherical mass approximately 1,948 km in radius, weighing about half a billion trillion tonnes (5.6e23 kg). Certainly that's a factor of ten off the mass of the Earth, but it's still a tad much. You could get away with a lot less mass if you had extremely dense materials (neutronium, strange matter), but being able to build structures using such materials is speculative at this point. The faster you could 'spin' it (get it closer to the speed of light). The less mass you would need to start with though right? -- Matthew Hagston |
#9
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Matthew Hagston wrote:
The faster you could 'spin' it (get it closer to the speed of light). The less mass you would need to start with though right? The only advantage this gives you is in density. In all other aspects this scheme is dramatically more difficult than just using a pile of matter. And it is insanely more difficult and cumbersome than just using acceleration (e.g. rotation). Unfortunately, even that benefit is very tiny and almost inconsequential. The problem is that ordinary matter, even diamond or buckytubes, is just not strong enough to store enough rotational energy to significantly affect its mass. Consider that the maximum amount of energy storable via this method is similar to the energy stored in the chemical bonds of the material, and that energy is similar in degree to the energy released by chemical explosives. Now compare that to the energy density of matter and the amount of energy released by just a tiny amount of matter (e.g. much less than 1% of the mass in the case of fission or fusion explosions, 100% in the case of anti-matter, matter annihilations). Even given all that (namely, the ability to store on the order of 20 *megatons* (TNT equiv.) of energy per kg) you would have improved the mass/energy density by a mere factor of 2, if that. Most likely though, since you would be forced to use materials with strong covalent bonds (e.g. carbon compounds) you would start out at a relative disadvantage in terms of density compared to using the densest matterials avaible (e.g. Lead, Uranium). So you would gain no advantage at all. |
#10
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In article ,
Christopher M. Jones wrote: No, only if you insist on having 1G at a distance of some 6400km. At one-millionth the distance, you need one-trillionth (10^-12) the mass. Still kind of a lot, mind you... I already thought of that. The problem is one of density. Realistically, you can't get convenient chunks of matter that are denser than about 18 g/cm^3 (e.g. Uranium). Remember, the whole point of the question that started this particular thread is (essentially) that "mass" and "matter" are not the same thing. Energy too has mass, and the mass of the hypothetical disk with the relativistic spin is dominated by its energy content, not its matter content. That is, its density at rest is basically irrelevant. What *is* relevant, alas, is the impossibly high structural strength it requires. With the strongest materials we've got, flywheel energy storage struggles to be competitive with batteries. This falls many orders of magnitude short of what's needed to store significant *masses* of energy. There is room for improvement in the materials, notably with the nanotube composites that many people are trying to make, but that's about one order of magnitude, which is nowhere near enough. Plus, as others have pointed out, transporting such vast amounts of energy is much harder than transporting equivalent amounts of matter. The entire energy output of the Sun is only about four million tons per second. -- "Think outside the box -- the box isn't our friend." | Henry Spencer -- George Herbert | |
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