The problem of incorporating gravity with QM is not a shortcoming of special relativity but of general relativity. (QM doesn't have a problem with the macroscopic world, it just isn't necessary because quantum effects in this realm are very very small).
QM has no problem with special relativistic effects. This is the subject of Quantum Field Theory. Quantum Theory though does in fact have some fundamental problems with gravity in particular and general relativity in general.
As far as gravity goes the problem is in the inability to find the virtual particle that mediates the force. In E&M the photon mediates the force. The strong nuclear force is mediated by mesons. The graviton has been postulated to be the mediating virtual particle but one has never been detected. This is actually an indication of a deeper problem - that of quantizing the field.
All of the the other fields can be quantized because the source of the field occurs in discrete amounts. For example the charge of an electron is the smallest charge anything can have, any charged object has a charge that is an integer multiple of the charge of an electron. If General Relativity is correct then we cannot quantize the gravitational field because it does not actually "emanate" from an object but is in fact the topology of spacetime due to the prescence of energy/mass. In order to quantize the gravitational field then me must quantize space and time itself. This would put a lower limit on length and time scales. Which is actually correct I am not going to hazard a guess, however this problem makes quantum theory and GR contradictory.
Personally I expect Quantum Theory isn't quite right, although it works quite well. I base this on the fact that Quantum Theory is based on a linear differential equation. I expect this is actually just the linear term of a nonlinear differential equation, but the non linear terms in all cases we have ever witnessed are incredibly small compared to the linear term. I have absolutely no evidence for this it is just a hunch.
Special Relativity unlike General Relativity is not fundamentally contradictory with any other theory I know of (unless you count newtonian mechanics which we know to be wrong). I already mentioned Quantum field theory as a combination of Quantum theory and SR. In addition SR is inherently compatible with E&M. E&M is goverend by Maxwells equations which are extremely acurate and have never (to my knowledge) failed. Maxwells equations are invariant under the lorenz transformations of special relativity, but are not invariant under the galilean transformations of newtonian mechanics. Let me explain this another way - When you change reference frames we must transform the equations that describe the dynamics of the system. Special relativity uses a lorenz transformation, whereas newtonian mechanics uses a galilean transformation. Maxwells equations have the same form when a lorenz transformation is performed but are different when we do a galilean transformation (which would imply the laws of physics are different depending on your reference frame). This is a relatively unknown, but very significant triumph of Special Relativity (theoretically and historically - Einstein noticed the lorenz invariance in Maxwells equations which led him to believe that is how transformations from reference frame to reference frame should be made).
As far as the experiment mentioned in the article there are going to be both SR and GR effects since the ISS is a non inertial reference frame. IMO and descrepancy in the result compared to theory could be in a problem with either theory, it IMO cannot show there is a problem with SR, it can only conclude there is a problem with one or the other. My guess is that the researchers will get the predicted result within experimental error.
In most sucessful OSS projects they are attempting to solve a computer science project. Most of the developers on these projects are computer scientists (either professionally or as a hobby) so they are definitely qualified for this.
For air traffic control however we are not talking about a computer science project. Computer science is just a means to an end in this case. Computer scientists are not qualified to solve this problem since they are not trained in the science envolved in tracking and managing air traffic. They are valuable only for one aspect of solving the problem.
For a problem like this you need a mixture of "pure" scientists, computer scientists, and some people in between. A proprietary model will work better here because there is a strict management structure that (in theory) can assemble the appropriate people from the variety of fields needed to solve the problem.
I see OSS as the best way to solve basic computer science problems (Operating Systems, networking, user interfaces, etc.). With open tools that solve these computer science problems that leaves people free to use these tools to attack "real world" problems with the assistance of computers.
The fact that the gravitational force the sun exhibits on the moon is greater than the gravitational force the earth exhibits on the moon is irrelevant. The sun exerts a force on both the earth and moon and causes a (rougly) equal acceleration on the two bodies.
Tidal forces are a result of differences in gravitational forces from one side of a body to another. Since the sun is so far away these differences are much smaller than those the earth experiences from the moon, and those that the moon experiences from the earth. It isn't the strength of the gravitational field that matters, but rather the field gradient that is important. Because of the proximity of the earth to the moon, this gradient is much greater so the tidal forces of the earth on the moon and vice versa are much more pronounced.
Check out the following links.
From the astronomy department at the university of Arizona Check the bottom of the page.
From the physics and astronomy department at the University of Tenessee
From the physics department at UNLV. There is a good discussion here about why the tidal bulge leads the moon. It also touches on the effect of the solar tidal forces. It isn't to pull the moon away though, but instead to tidal lock to the sun.
You are correct about the length of the day during the dinosaurs, I don't know where I got that number, but loosing 10 hours in a few hundred million years does seem too rapid in hind site.
Gravitational friction isn't the correct term. The Moon is moving away from earth because of tidal forces. You are correct though that it is because of the interaction with the oceans.
What is happening is the tidal bulge that is created by the moons gravity leads the moon slightly. This inhomogeneity gives a slight non-radial component to the gravitational force the earth exerts on the moon. Since the force is leading the moon, it pulls it along in its orbit just a bit, this speeds up the moon which in turn causes the orbit to move outward.
The moon however will not escape the gravitational pull of earth. The lunar orbit will eventually become stable. When it does the orbital period of the moon will be exactly equal to the rotational period of the earth (the same forces that are speeding up the moons orbit are slowing down the earths rotation - in fact a day on earth used to be much shorter - I think I remember reading that it was about 14 hours during the period of the dinosaurs). This matching of orbital period to rotational period is common, it is called a spin orbit coupling. The moon is already coupled to the earth - thus the orbital period of the moon is almost exactly equal to its rotational period, that is why one side of the moon always faces the earth. Mercurys orbital period is also coupled to it's own rotational period, in this case it isn't 1:1 but 2:3 (2 rotations every 3 orbits about the sun). Plutos orbit is also coupled to Neptunes, this is why despite the fact Plutos orbit crosses Neptunes, they will never collide, because there orbits are coupled in just the right way.
By the way when the earth moon system becomes stable a month will take exactly 1 day. However by then a day will be approximately 1000 hours. Just like one side of the moon always faces the earth, one side of the earth will always face the moon, and anything on the other side of the earth will never see the moon, and the moon will always be in exactly the same part of the sky for those that can see it.
Thought I would mention a couple of things related to this subject.
1) Our sun is not big enough to go Super Nova, so don't worry about that. A Nova is a different thing that occurs in binary star systems so we don't have to worry about that either. What we do have to worry about is when the sun enters the Red Giant phase and begins to expand. That is what these scientists are pondering.
2) Any 3 body gravitational system is chaotic. A chaotic system does not mean that is is wild and out of control. It means that it is very difficult to predict because the system is very sensitive to initial conditions. However, this is often a benefit because a chaotic system can exhibit a large range of behavior, whereas a non chaotic system is stuck in it's stable behavior. Also because of the chaotic nature of a 3 body system very small perturbations can eventually greatly effect the system. This means that we would not need a very large asteroid to move the earth, a small one that approaches just right would do the trick, and it would happen over a very large time period (millions of years). However because of the chaotic nature of the system we cannot exactly predict exactly where the earth would end up (we could eliminate the possiblity of it plunging into the sun, or being ejected from the solar system). To pull this off we would probably need a series of asteroids to occasionally redirect the earth slightly (perhaps every few thousand years). Since the forces involved would be small the effects of tidal forces and effects on the environment would be small and gradual.
3) The earth already is moving away from the sun, because the sun is losing mass to the solar wind. My guess would be getting the mass loss of the sun correct would be the most difficult thing to work into the calculations since it isn't totally constant, and probably will become much more erratic as the sun begins to approach the red giant phase.
4) My guess is the thing people of the future would have to worry about isn't the sun expanding and heating the earth too much, but the sun will probably become much less stable as far as radiation output causing rapid heating (several degrees over a few hundred years) followed by rapid cooling. This kind of variability will probably wreck havoc on the environment. (This is all assuming we haven't already screwed things up ourselves).
5) This study is more relavent than you might think. While it will probably never be used to actually move the earth, the same techniques could be used to move things (spacecraft, asteroids for raw materials, etc..) without vast expendature of fuel as is currently done, where much of what we do is the brute force method. I read a paper that described how to get a spacecraft to the moon using less energy than a homan transfer (the most efficient way we currently change orbits). The method used the fact the earth, sun, moon system is a chaotic 3 body system. The drawback was that it took years to get the spacecraft to the moon.
Slashdot Mirror
The problem of incorporating gravity with QM is not a shortcoming of special relativity but of general relativity. (QM doesn't have a problem with the macroscopic world, it just isn't necessary because quantum effects in this realm are very very small).
QM has no problem with special relativistic effects. This is the subject of Quantum Field Theory. Quantum Theory though does in fact have some fundamental problems with gravity in particular and general relativity in general.
As far as gravity goes the problem is in the inability to find the virtual particle that mediates the force. In E&M the photon mediates the force. The strong nuclear force is mediated by mesons. The graviton has been postulated to be the mediating virtual particle but one has never been detected. This is actually an indication of a deeper problem - that of quantizing the field.
All of the the other fields can be quantized because the source of the field occurs in discrete amounts. For example the charge of an electron is the smallest charge anything can have, any charged object has a charge that is an integer multiple of the charge of an electron. If General Relativity is correct then we cannot quantize the gravitational field because it does not actually "emanate" from an object but is in fact the topology of spacetime due to the prescence of energy/mass. In order to quantize the gravitational field then me must quantize space and time itself. This would put a lower limit on length and time scales. Which is actually correct I am not going to hazard a guess, however this problem makes quantum theory and GR contradictory.
Personally I expect Quantum Theory isn't quite right, although it works quite well. I base this on the fact that Quantum Theory is based on a linear differential equation. I expect this is actually just the linear term of a nonlinear differential equation, but the non linear terms in all cases we have ever witnessed are incredibly small compared to the linear term. I have absolutely no evidence for this it is just a hunch.
Special Relativity unlike General Relativity is not fundamentally contradictory with any other theory I know of (unless you count newtonian mechanics which we know to be wrong). I already mentioned Quantum field theory as a combination of Quantum theory and SR. In addition SR is inherently compatible with E&M. E&M is goverend by Maxwells equations which are extremely acurate and have never (to my knowledge) failed. Maxwells equations are invariant under the lorenz transformations of special relativity, but are not invariant under the galilean transformations of newtonian mechanics. Let me explain this another way - When you change reference frames we must transform the equations that describe the dynamics of the system. Special relativity uses a lorenz transformation, whereas newtonian mechanics uses a galilean transformation. Maxwells equations have the same form when a lorenz transformation is performed but are different when we do a galilean transformation (which would imply the laws of physics are different depending on your reference frame). This is a relatively unknown, but very significant triumph of Special Relativity (theoretically and historically - Einstein noticed the lorenz invariance in Maxwells equations which led him to believe that is how transformations from reference frame to reference frame should be made).
As far as the experiment mentioned in the article there are going to be both SR and GR effects since the ISS is a non inertial reference frame. IMO and descrepancy in the result compared to theory could be in a problem with either theory, it IMO cannot show there is a problem with SR, it can only conclude there is a problem with one or the other. My guess is that the researchers will get the predicted result within experimental error.
In most sucessful OSS projects they are attempting to solve a computer science project. Most of the developers on these projects are computer scientists (either professionally or as a hobby) so they are definitely qualified for this.
For air traffic control however we are not talking about a computer science project. Computer science is just a means to an end in this case. Computer scientists are not qualified to solve this problem since they are not trained in the science envolved in tracking and managing air traffic. They are valuable only for one aspect of solving the problem.
For a problem like this you need a mixture of "pure" scientists, computer scientists, and some people in between. A proprietary model will work better here because there is a strict management structure that (in theory) can assemble the appropriate people from the variety of fields needed to solve the problem.
I see OSS as the best way to solve basic computer science problems (Operating Systems, networking, user interfaces, etc.). With open tools that solve these computer science problems that leaves people free to use these tools to attack "real world" problems with the assistance of computers.
The fact that the gravitational force the sun exhibits on the moon is greater than the gravitational force the earth exhibits on the moon is irrelevant. The sun exerts a force on both the earth and moon and causes a (rougly) equal acceleration on the two bodies.
Tidal forces are a result of differences in gravitational forces from one side of a body to another. Since the sun is so far away these differences are much smaller than those the earth experiences from the moon, and those that the moon experiences from the earth. It isn't the strength of the gravitational field that matters, but rather the field gradient that is important. Because of the proximity of the earth to the moon, this gradient is much greater so the tidal forces of the earth on the moon and vice versa are much more pronounced.
Check out the following links.
From the astronomy department at the university of Arizona Check the bottom of the page.
From the physics and astronomy department at the University of Tenessee
From the physics department at UNLV. There is a good discussion here about why the tidal bulge leads the moon. It also touches on the effect of the solar tidal forces. It isn't to pull the moon away though, but instead to tidal lock to the sun.
You are correct about the length of the day during the dinosaurs, I don't know where I got that number, but loosing 10 hours in a few hundred million years does seem too rapid in hind site.
Gravitational friction isn't the correct term. The Moon is moving away from earth because of tidal forces. You are correct though that it is because of the interaction with the oceans.
What is happening is the tidal bulge that is created by the moons gravity leads the moon slightly. This inhomogeneity gives a slight non-radial component to the gravitational force the earth exerts on the moon. Since the force is leading the moon, it pulls it along in its orbit just a bit, this speeds up the moon which in turn causes the orbit to move outward.
The moon however will not escape the gravitational pull of earth. The lunar orbit will eventually become stable. When it does the orbital period of the moon will be exactly equal to the rotational period of the earth (the same forces that are speeding up the moons orbit are slowing down the earths rotation - in fact a day on earth used to be much shorter - I think I remember reading that it was about 14 hours during the period of the dinosaurs). This matching of orbital period to rotational period is common, it is called a spin orbit coupling. The moon is already coupled to the earth - thus the orbital period of the moon is almost exactly equal to its rotational period, that is why one side of the moon always faces the earth. Mercurys orbital period is also coupled to it's own rotational period, in this case it isn't 1:1 but 2:3 (2 rotations every 3 orbits about the sun). Plutos orbit is also coupled to Neptunes, this is why despite the fact Plutos orbit crosses Neptunes, they will never collide, because there orbits are coupled in just the right way.
By the way when the earth moon system becomes stable a month will take exactly 1 day. However by then a day will be approximately 1000 hours. Just like one side of the moon always faces the earth, one side of the earth will always face the moon, and anything on the other side of the earth will never see the moon, and the moon will always be in exactly the same part of the sky for those that can see it.
Thought I would mention a couple of things related to this subject.
1) Our sun is not big enough to go Super Nova, so don't worry about that. A Nova is a different thing that occurs in binary star systems so we don't have to worry about that either. What we do have to worry about is when the sun enters the Red Giant phase and begins to expand. That is what these scientists are pondering.
2) Any 3 body gravitational system is chaotic. A chaotic system does not mean that is is wild and out of control. It means that it is very difficult to predict because the system is very sensitive to initial conditions. However, this is often a benefit because a chaotic system can exhibit a large range of behavior, whereas a non chaotic system is stuck in it's stable behavior. Also because of the chaotic nature of a 3 body system very small perturbations can eventually greatly effect the system. This means that we would not need a very large asteroid to move the earth, a small one that approaches just right would do the trick, and it would happen over a very large time period (millions of years). However because of the chaotic nature of the system we cannot exactly predict exactly where the earth would end up (we could eliminate the possiblity of it plunging into the sun, or being ejected from the solar system). To pull this off we would probably need a series of asteroids to occasionally redirect the earth slightly (perhaps every few thousand years). Since the forces involved would be small the effects of tidal forces and effects on the environment would be small and gradual.
3) The earth already is moving away from the sun, because the sun is losing mass to the solar wind. My guess would be getting the mass loss of the sun correct would be the most difficult thing to work into the calculations since it isn't totally constant, and probably will become much more erratic as the sun begins to approach the red giant phase.
4) My guess is the thing people of the future would have to worry about isn't the sun expanding and heating the earth too much, but the sun will probably become much less stable as far as radiation output causing rapid heating (several degrees over a few hundred years) followed by rapid cooling. This kind of variability will probably wreck havoc on the environment. (This is all assuming we haven't already screwed things up ourselves).
5) This study is more relavent than you might think. While it will probably never be used to actually move the earth, the same techniques could be used to move things (spacecraft, asteroids for raw materials, etc..) without vast expendature of fuel as is currently done, where much of what we do is the brute force method. I read a paper that described how to get a spacecraft to the moon using less energy than a homan transfer (the most efficient way we currently change orbits). The method used the fact the earth, sun, moon system is a chaotic 3 body system. The drawback was that it took years to get the spacecraft to the moon.
Sorry that was so long winded.