I remember vaguely hearing that it is possible to solve the 3 body problem, using elliptic coordinates. But that it's nearly always easier to just throw it at a computer. No references though.
The idea is completely different. T9 and other phone predictive systems work on a large dictionary system, whereas Dasher works on a probabalistic language model (given the last 3 letters, what's the probability for each of the next possible letters) and offers the user the choice of each letter, with the target box sizes dependent on the probabilities. The simplest form of Dasher doesn't know any words at all, just the probability that bac is followed by a k etc.
based on evidence from type Ia supernovae distances and CMB anisotropies (and I'm including unpublished results that I have seen, and that should come out in the next few months), the universe is 30% baryonic (i.e. normal) matter, and 70% dark energy/dark matter.
The errors on these are about 10%
This produces a non-zero cosmological constant, and a flat universe (Omega = 1)
1) No one has a complete formulation of quantum mechanics either (the measurement problem is still completely unsolved, although some progress is being made). But quantum mechanics can produce accurate predictions to 12 significant figures. No theory can be called complete unless it is the theory of everything anyway.
2) is only relevant if the complete structure of m-theory is known, and it is the only theory of everything. work is still ongoing, and for the specific case of the ekopyrotic universe, concrete predicitons from m-theory and the ekopyrotic model are being worked out at the moment.
3) not yet, no, but the other theories are known to be incomplete experimentally or theoretically, m-theory hasn't been shown experimentally to be incomplete yet. Remember, you cannot prove a physical theory, only disprove.
4) the extra dimension proposed by m-theory is the minimum condition needed to make supersymmetry and all 5 string theories consistent with each other. No other known theory exists.
This is physics in action. The theory isn't complete, but it hasn't got anything wrong yet.
I'm not talking about string theories which deal with 10d line objects, of which there are 5, but the parent theory of all 5 string theories and supersymmetry, that deals with membranes in 11-d.
So far no one has produced any strong objections to m-theory, and m-theory has been used to produce a model (the Ekopyrotic model) for the instant of the big bang. The ramifications of this model are currently being worked out, by amoung others, Martin Rees, Steven Hawking and Neil Turok (in Cambridge alone). The current work is to calculate the effect the Ekopyrotic model has on nucleosynthesis, baryon fraction and primordial CMB imprints and structure formation in the early universe. With the advent of CMB anisotropy experiments such as the VSA, CBI, DASI, Planck and MAP, these predictions will be tested in the next decade or so.
M-Theory also has possible implications for results in within the reach of the LHC accelerator at CERN, which should start producing results of searches for supersymmetric particles about a decade from now.
QCD does have problems with renormalisation, and perturbation techniques at low energies, but these vanish as the energy of the particles increases.
I won't comment on you theory above until you have a working mathematical model for the theory.
Yes, which is why General relativity is so hard. Gravitational fields have energy and therefore mass, which produces more gravity. Therefore there must be interactions between gravitons.
I have often wondered (but never had the time, inclination or intelligence to go find out:)) how a quantum view of gravity would affect theories on black holes and the birth of the universe. Basically my question is: If gravitational attraction is carried by a particle (the graviton) as is conjectured by many scientists, then how can one of these escape from a black hole any more than another particle?
The latest theory of quantum gravity under discussion is the 11 dimensional m-theory, which models the universe as a four dimensional spacetime embedded in 10 space and 1 time dimensions. In this theory, gravity, and therefore gravitons, are the interaction between two closely seperated membranes, one of which is our universe. gravitons propagate in all 11 dimensions of the theory, and can therefore propagate out of the 4-d black holes 3-d event horizon by taking a trip through the higher dimensions.
It's not that Einstein was wrong, as his field equations still produce the correct results for large scale gravity in m theory, but just that he didn't go far enough towards a quantum theory of gravity, for which the mathematical tools just weren't available.
Theroetically, lasers produce a Gaussian beam that has a slight curvature, and therefore a divergence. The action of lenses can move the narrowest point of the beam to outside of the lasing cavity, but the amount of divergence is controlled entirely by the minimum width of the beam. It's the lovely relation, angle of divergence = wavelength / diameter of beam waist
(for sufficiently small angles)
This is identical to the diffraction equation as well (see earlier post on the size of a microwave dish).
Re:"only a few square km"
on
Lunar Lasers
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· Score: 1
Diffraction angle is given by the wavelength (about 1cm) divided by the size of the aperture(d), so 1cm/d has to be = 1000m = 1km.
So with a 1km dish (not unfeasible, given the lack of wind on the moon, and 1/6th of the gravity), you can get a beam ~1km^2.
There's probably meant to be some multipliers in the above, but I don't care about them.
Given that the latest physical evidence is that the universe is open, i.e. will keep expanding for ever, then the lifetime of the universe can only be defined as infinity. Given Hilbert's Hotel analogy, infinity minus 1 is infinity, and therefore the lifetime of the universe minus a day is an infinite time.
If the wavelength is 100th of currently used systems, then the area of pits on a cd type system can be 10,000th of the size, so that data densities could be 10,000 tims as great. Near UV light is actually about 1/3rd the wavelength of green light. However, UV photons also have 3 times as much energy, so the disc used would heat up more, and have to be stable against this, which would quite difficult for Write operations (assuming everything keeps the same as CD-RW).
The real power of these lasers for data storage may be in holographic systems, as there may be a way to store phase information at UV frequencies that can't be used for visible lasers. Holographic techniques would also allow data densities to scale as wavelength^-3, so that going from green to UV would give 27 times the data density (which is already estimated at 10Tb for 1 cubic inch in visible light systems)
The paper only reports optically driven lasing, which requires a Nd:YAG laser to drive the UV laser. Without electrically driven lasing at high integration densities, ZnO couldn't be used for optical storage and probably not in an optical computer. This will take some time to develop, if it is at all possible, depending on the ease of making electrical contacts, and the current density required to reach threshold. The use as a coherent imaging system is possible almost immediately though.
You're talking about a vacuum in a cylinder at most 1mm across (internally), with probably 1mm walls, that should take the 10^5 Pa required easily (standing on it would give a pressure of the order of 2x10^5, and you can stand on pipes with no problem whatsoever).
Why should they be grouped with perpertual motion?
Perpertual motion is fundamentally impossible under the laws of thermodynamics.
Cold Fusion on the other hand is not explained under the laws of nuclear physics, but it is not totally ruled out (the key point is that nuclear physics predicts that there should be a vanishingly small probability for the reaction to occur, not that it is impossible).
Likewise, anti-gravity devices cannot proved impossible, and with the current results showing that the expansion of the universe is accelerating, along with the inflationary version of the big bang model, anti-gravity is required to explain the current cosmology of the universe, making the possibility of an anti-gravity device plausible.
...has produced plenty of results, i.e. the Mike test, and almost every other fusion bomb test since then.
Also JET ran at 500MW for 50 seconds at a time, 20 times a day for 3 months during the 1997 D-T campaign, I know because I was working with cameras damaged by the radiation from that last summer. Imperial College, London has sucessfully produced neutron and He yield by passing masssive currents through frozen deuterium wires to produce an implosion and inertial confinement.
These are just the experiments I've been lectured on.
(Super) Kamiokande and the Home Salt mine detectors have been picking up solar and cosmological neutrinos for years now.
But being at the south pole they get a slightly different view, due to the different position in space, as neutrinos pretty much ignore matter, like the Earth.
Hitachi made 100GHz microprocessor elements 5 years ago, using superconducting technology. The first 1GHz procesor was made using this in 1990. Shame that they need liquid helium and that noone could write decent compilers for it
Maybe you are referring to the "hidden variables" interpretation, which is quite controversial and almost debunked.
In fact it's proven entirely incorrect by the avent of Bell's theorem testing experiments. Hidden variables theories obey a particular inequality known as Bell's inequality which is to do with the probability of correlations between two entangled particles. Quantum Mechanics violates this inequality, and, as has been measured in several experiments, so does the real world.
This is the frequency band that mobile phones use (GSM 900) so couldn't there be problems with interference, and public hype along the lines of mobile phone radiation.
Also at these sort of frequencies you have to use microstrip waveguides to carry your signals, as standard wires don't work so good, so would interconnects and the like have to be redesigned?
Anyway, most computers are limited by memory bandwidth nowadays, and 10GHz chips only makes this worse. To get performance up a lot it would probably be better to improve the memory clock by a factor of ten than the raw processor speed.
It is possible that there exists a orbit around the asteroid that eventually closes with out passing through the asteroid, it just won't be circular. It's more likely to be some form of space filling orbit that won't ever close, but won't hit the asteroid or get to far from it though. On the other hand, you couldn't predict the exact orbit it will follow as this is a pretty much classical example of a chaotic system.
Slashdot Mirror
I remember vaguely hearing that it is possible to solve the 3 body problem, using elliptic coordinates. But that it's nearly always easier to just throw it at a computer. No references though.
It doesn't use a dictionary, but a language model that knows the relative probabilities of which letter follows the last few.
The idea is completely different. T9 and other phone predictive systems work on a large dictionary system, whereas Dasher works on a probabalistic language model (given the last 3 letters, what's the probability for each of the next possible letters) and offers the user the choice of each letter, with the target box sizes dependent on the probabilities. The simplest form of Dasher doesn't know any words at all, just the probability that bac is followed by a k etc.
Because it's being worked on by a single researcher, and they know C and tcl. This isn't a big company R&D effort at the moment.
umm, you're wrong.
based on evidence from type Ia supernovae distances and CMB anisotropies (and I'm including unpublished results that I have seen, and that should come out in the next few months), the universe is 30% baryonic (i.e. normal) matter, and 70% dark energy/dark matter.
The errors on these are about 10%
This produces a non-zero cosmological constant, and a flat universe (Omega = 1)
beside's it's Occam's razor.
In response
1) No one has a complete formulation of quantum mechanics either (the measurement problem is still completely unsolved, although some progress is being made). But quantum mechanics can produce accurate predictions to 12 significant figures. No theory can be called complete unless it is the theory of everything anyway.
2) is only relevant if the complete structure of m-theory is known, and it is the only theory of everything. work is still ongoing, and for the specific case of the ekopyrotic universe, concrete predicitons from m-theory and the ekopyrotic model are being worked out at the moment.
3) not yet, no, but the other theories are known to be incomplete experimentally or theoretically, m-theory hasn't been shown experimentally to be incomplete yet. Remember, you cannot prove a physical theory, only disprove.
4) the extra dimension proposed by m-theory is the minimum condition needed to make supersymmetry and all 5 string theories consistent with each other. No other known theory exists.
This is physics in action. The theory isn't complete, but it hasn't got anything wrong yet.
I'm not talking about string theories which deal with 10d line objects, of which there are 5, but the parent theory of all 5 string theories and supersymmetry, that deals with membranes in 11-d.
So far no one has produced any strong objections to m-theory, and m-theory has been used to produce a model (the Ekopyrotic model) for the instant of the big bang. The ramifications of this model are currently being worked out, by amoung others, Martin Rees, Steven Hawking and Neil Turok (in Cambridge alone). The current work is to calculate the effect the Ekopyrotic model has on nucleosynthesis, baryon fraction and primordial CMB imprints and structure formation in the early universe. With the advent of CMB anisotropy experiments such as the VSA, CBI, DASI, Planck and MAP, these predictions will be tested in the next decade or so.
M-Theory also has possible implications for results in within the reach of the LHC accelerator at CERN, which should start producing results of searches for supersymmetric particles about a decade from now.
QCD does have problems with renormalisation, and perturbation techniques at low energies, but these vanish as the energy of the particles increases.
I won't comment on you theory above until you have a working mathematical model for the theory.
Yes, which is why General relativity is so hard. Gravitational fields have energy and therefore mass, which produces more gravity. Therefore there must be interactions between gravitons.
I have often wondered (but never had the time, inclination or intelligence to go find out :)) how a quantum view of gravity would affect theories on black holes and the birth of the universe. Basically my question is: If gravitational attraction is carried by a particle (the graviton) as is conjectured by many scientists, then how can one of these escape from a black hole any more than another particle?
The latest theory of quantum gravity under discussion is the 11 dimensional m-theory, which models the universe as a four dimensional spacetime embedded in 10 space and 1 time dimensions. In this theory, gravity, and therefore gravitons, are the interaction between two closely seperated membranes, one of which is our universe. gravitons propagate in all 11 dimensions of the theory, and can therefore propagate out of the 4-d black holes 3-d event horizon by taking a trip through the higher dimensions.
It's not that Einstein was wrong, as his field equations still produce the correct results for large scale gravity in m theory, but just that he didn't go far enough towards a quantum theory of gravity, for which the mathematical tools just weren't available.
It is an inverse cube law. Differential (tidal) forces go as the differential of the basic force law, which is r^-2 radially.
At one point the Deutsch Mark was worth 1 trillionth of a US dollar.
Theroetically, lasers produce a Gaussian beam that has a slight curvature, and therefore a divergence. The action of lenses can move the narrowest point of the beam to outside of the lasing cavity, but the amount of divergence is controlled entirely by the minimum width of the beam. It's the lovely relation, angle of divergence = wavelength / diameter of beam waist
(for sufficiently small angles)
This is identical to the diffraction equation as well (see earlier post on the size of a microwave dish).
Diffraction angle is given by the wavelength (about 1cm) divided by the size of the aperture(d), so 1cm/d has to be = 1000m = 1km.
So with a 1km dish (not unfeasible, given the lack of wind on the moon, and 1/6th of the gravity), you can get a beam ~1km^2.
There's probably meant to be some multipliers in the above, but I don't care about them.
Given that the latest physical evidence is that the universe is open, i.e. will keep expanding for ever, then the lifetime of the universe can only be defined as infinity. Given Hilbert's Hotel analogy, infinity minus 1 is infinity, and therefore the lifetime of the universe minus a day is an infinite time.
If the wavelength is 100th of currently used systems, then the area of pits on a cd type system can be 10,000th of the size, so that data densities could be 10,000 tims as great. Near UV light is actually about 1/3rd the wavelength of green light. However, UV photons also have 3 times as much energy, so the disc used would heat up more, and have to be stable against this, which would quite difficult for Write operations (assuming everything keeps the same as CD-RW).
The real power of these lasers for data storage may be in holographic systems, as there may be a way to store phase information at UV frequencies that can't be used for visible lasers. Holographic techniques would also allow data densities to scale as wavelength^-3, so that going from green to UV would give 27 times the data density (which is already estimated at 10Tb for 1 cubic inch in visible light systems)
The paper only reports optically driven lasing, which requires a Nd:YAG laser to drive the UV laser. Without electrically driven lasing at high integration densities, ZnO couldn't be used for optical storage and probably not in an optical computer. This will take some time to develop, if it is at all possible, depending on the ease of making electrical contacts, and the current density required to reach threshold. The use as a coherent imaging system is possible almost immediately though.
He wrote one line for them, in collaboration with Graham Chapman.
Oh, and he nearly killed all of them by driving them the wrong way down a foggy motorway in a camper van.
Don't see why it should be that hard.
You're talking about a vacuum in a cylinder at most 1mm across (internally), with probably 1mm walls, that should take the 10^5 Pa required easily (standing on it would give a pressure of the order of 2x10^5, and you can stand on pipes with no problem whatsoever).
Why should they be grouped with perpertual motion?
Perpertual motion is fundamentally impossible under the laws of thermodynamics.
Cold Fusion on the other hand is not explained under the laws of nuclear physics, but it is not totally ruled out (the key point is that nuclear physics predicts that there should be a vanishingly small probability for the reaction to occur, not that it is impossible).
Likewise, anti-gravity devices cannot proved impossible, and with the current results showing that the expansion of the universe is accelerating, along with the inflationary version of the big bang model, anti-gravity is required to explain the current cosmology of the universe, making the possibility of an anti-gravity device plausible.
...has produced plenty of results, i.e. the Mike test, and almost every other fusion bomb test since then.
Also JET ran at 500MW for 50 seconds at a time, 20 times a day for 3 months during the 1997 D-T campaign, I know because I was working with cameras damaged by the radiation from that last summer. Imperial College, London has sucessfully produced neutron and He yield by passing masssive currents through frozen deuterium wires to produce an implosion and inertial confinement.
These are just the experiments I've been lectured on.
See fusion.org
They haven't discovered anything particularly new
(Super) Kamiokande and the Home Salt mine detectors have been picking up solar and cosmological neutrinos for years now.
But being at the south pole they get a slightly different view, due to the different position in space, as neutrinos pretty much ignore matter, like the Earth.
Hitachi made 100GHz microprocessor elements 5 years ago, using superconducting technology. The first 1GHz procesor was made using this in 1990. Shame that they need liquid helium and that noone could write decent compilers for it
Maybe you are referring to the "hidden variables" interpretation, which is quite controversial and almost debunked.
In fact it's proven entirely incorrect by the avent of Bell's theorem testing experiments. Hidden variables theories obey a particular inequality known as Bell's inequality which is to do with the probability of correlations between two entangled particles. Quantum Mechanics violates this inequality, and, as has been measured in several experiments, so does the real world.
This is the frequency band that mobile phones use (GSM 900) so couldn't there be problems with interference, and public hype along the lines of mobile phone radiation.
Also at these sort of frequencies you have to use microstrip waveguides to carry your signals, as standard wires don't work so good, so would interconnects and the like have to be redesigned?
Anyway, most computers are limited by memory bandwidth nowadays, and 10GHz chips only makes this worse. To get performance up a lot it would probably be better to improve the memory clock by a factor of ten than the raw processor speed.
It is possible that there exists a orbit around the asteroid that eventually closes with out passing through the asteroid, it just won't be circular. It's more likely to be some form of space filling orbit that won't ever close, but won't hit the asteroid or get to far from it though. On the other hand, you couldn't predict the exact orbit it will follow as this is a pretty much classical example of a chaotic system.