I already compress my files with gzip and bzip2. My images are PNG and JPEG. What good is this to me? Surely this will just slow me down and make my files larger?
Unfortunately, that's exactly what antialiasing is designed to do, to "smooth out" the sharp changes between light and dark to disguise individual pixels. If you have good eyesight and a high-resultion display, antialiasing makes things look blurred.
There was no physics that allowed > Mach 1 speeds to be achieved
Not true. Newtonian physics allows Mach 1 to be broken. Einsteinian physics does not allow c to be broken (or to be achieved with rest mass).
I see what you mean. However, wouldn't the amount of noise in these bands be much higher than you would expect to occur naturally? If you took a spectrum of radiation coming from the vicinity of earth (assuming it wasn't right in front of the sun) wouldn't they be disproportionately strong?
Unfortunately, it's not likely to be in our lifetime. (Oh, that it were!!)
Oh, that is were, indeed. We can console ourselves somewhat with things like SETI and the fact that with advanced nuclear technology we should be able to explore the Solar System. There must be so much there waiting to be discovered. I only wish those with the money and the brains would get on and do it!
We've already been sending out artificial radio waves from Earth for around 100 years. If there was intelligent life there that had sensitive enough radio detectors they may already have detected us.
I agree with you that we shouldn't be too pessimistic, however the Wright Brothers' flight was more of an engineering challenge than a scientific one. They required no novel physics to accomplish their feat, only the application of known physical laws. It will be possible for us to explore our own solar system using known physics by using nuclear propulsion (fission and some day fusion) and even solar sails. However, travel to other stars in less than a human life-time in our frame of reference will require super-luminal speeds. There is no physics known yet that will allow us to achieve this. So, interstellar travel will be a lot harder for us to achieve than the Wright Brothers' first powered flight.
Stars up to 1.44 times the mass of the sun (calculated first by Chandrasekar, a really nifty guy who wasn't believed at all at the time) are supported by electron pressure.
You're thinking of the electron degeneracy pressure that keeps white dwarf stars up i.e. small stars who've run out of nuclear fuel that can no longer support their own mass by radiation (i.e. photon) pressure. Electron degeneracy pressure results from the Pauli Exclusion principal which prevents two electrons taking up the same quantum states. When matter is in the electron-degenerate state, all of the electrons are packed as closely as they can be in their quantum states. If the mass of the star is greater, electron degeneracy pressure is no longer sufficient. The elctrons are pushed into the atomic nuclei of the star's matter converting all the protons to neutrons. The star has now become a neutron star and is supported by neutron degeneracy pressure. If the mass is greater than a certain amount (can't remember, about 5 solar masses?) the star may become a quark star, but probably becomes a black hole.
Firstly, unused nuclear fuel is not very radioactive relatively speaking and is not very toxic. Secondly, the fuel can (and is) built into very strong and resilliant "cans" and can be further protected to the point that even a fall from a great height such as earth-orbit will not result in any radioactive release. Thirdly, any engineer woth their salt will design the darned thing such that it will not start its nuclear reactor (when the nasty fission products start to be produced) until the craft is either a significant distance away from earth already, or has achieved escape velocity and can not fall back to earth.
I am a qualified nuclear engineer with several years reactor physics experience at a nuclear power station.
No, I am definitely referring to photon pressure. High energy gamma rays are produced by the nuclear reactions in the stellar core. They collide with atoms on their way out, loosing energy (and momentum), exerting a net outwards force on the gas, and becoming longer wavelength (down to visible frequencies). On average, a photon takes a million years to work its way out of the stellar core.
Never mind whether the rocket's moving or not. There is no such thing as a perfect mirror. Some of the photon's energy will be lost when they strike the mirror, so the photons will be red-shifted in that way. They will be re-radiated with less energy (and hence momentum) than they hit the mirror with, hence a net "push" on the mirror.
Whe I was studying Astrophysics many years ago, we learned that photon pressure is what "keeps stars up" i.e. the pressure exerted by the photons produced in the star exerted on the matter comprising the star are what prevents it from collapsing under its own gravity. My mind is rusty, but we derived the equations and solved them for certain masses of stars. We also looked at solar sails using similar maths. I suspect that solar sailing is possible, since the physics is similar to what's going on inside a star...
In that case, the USA's days as the leading nation on earth (financially, technologically etc.) are numbered. As they choose to rest on their laurels, they will stagnate and then wither. It's sad to see the vitality disappear from what was once such a great country. Such short-sightedness will end in tears.
My ZX81 didn't have any colours at all, only black and white. It went black and blue when the TV set broke though. And at my last job, the computer didn't even have a CRT on the console. It had a teletype, and the ink had run out and they stopped making ribbons years ago. We had surgeons gloves and a bottle of Quink.
because 32-bit protected mode hardware wasn't available until the 80386 was released. Which came out in 1985 if I am not mistaken. I remember the first 386 PCs in about 1987? Initially they ran at 14.6MHz (they were intended to run at 16MHz). Like I said though, backwards compatability with old DOS apps (and having to use the BIOS) are what held back proper OSs. Oh well, maybe my memory has rotted away since then.
It depends how big the chunk is. Basically, the impact needs to accelerate the "chunk" form zero to escape velocity. Escape velocity is the same for everything (it only depends on the earth's mass and the distance from the centre of mass) but varies very very very slightly with height. How much of a push your chunk needs depends on its mass.
The PC might not have been technically superior to other machines of the era bot they had the adaptive edge of being an open infrastructure.
The IBM PC was never an open infrastructure. It was closed, however this is a common misconception nowadays. What actually happened is that people reverse-engineered the PC, documented it, and did a "clean-room" reimplementation to avoid litigation ie the implementors were not part of the reverse-engineering teams. This was especially important for the ROM BIOS of the PC which was essential for writing any sort of software in those days since MS-DOS was so limited (ie you gad to speak straigh to the BIOS). So if you didn't have an IBM-compatible BIOS you weren't "PC Compatible". You may have been able to run a port of MS-DOS though. This was also one of the reasons it took so long for "real" operating systems to take of on PCs. The BIOS only worked in Real Mode and hardware was so disparate and open source hadn't been invented, so no one got around to writing a Protected Mode (32-bit) OS for a long time...
Slashdot Mirror
RTFA? This is slashdot young man!
I already compress my files with gzip and bzip2. My images are PNG and JPEG. What good is this to me? Surely this will just slow me down and make my files larger?
Unfortunately, that's exactly what antialiasing is designed to do, to "smooth out" the sharp changes between light and dark to disguise individual pixels. If you have good eyesight and a high-resultion display, antialiasing makes things look blurred.
There was no physics that allowed > Mach 1 speeds to be achieved
Not true. Newtonian physics allows Mach 1 to be broken. Einsteinian physics does not allow c to be broken (or to be achieved with rest mass).
I see what you mean. However, wouldn't the amount of noise in these bands be much higher than you would expect to occur naturally? If you took a spectrum of radiation coming from the vicinity of earth (assuming it wasn't right in front of the sun) wouldn't they be disproportionately strong?
Beavis, come here wile I kick your ass...
There is no such thing as a perfectly rigid body. Everything else follows from this.
Oh, that is were, indeed. We can console ourselves somewhat with things like SETI and the fact that with advanced nuclear technology we should be able to explore the Solar System. There must be so much there waiting to be discovered. I only wish those with the money and the brains would get on and do it!
We've already been sending out artificial radio waves from Earth for around 100 years. If there was intelligent life there that had sensitive enough radio detectors they may already have detected us.
I agree with you that we shouldn't be too pessimistic, however the Wright Brothers' flight was more of an engineering challenge than a scientific one. They required no novel physics to accomplish their feat, only the application of known physical laws. It will be possible for us to explore our own solar system using known physics by using nuclear propulsion (fission and some day fusion) and even solar sails. However, travel to other stars in less than a human life-time in our frame of reference will require super-luminal speeds. There is no physics known yet that will allow us to achieve this. So, interstellar travel will be a lot harder for us to achieve than the Wright Brothers' first powered flight.
Thanks for that.
You're thinking of the electron degeneracy pressure that keeps white dwarf stars up i.e. small stars who've run out of nuclear fuel that can no longer support their own mass by radiation (i.e. photon) pressure. Electron degeneracy pressure results from the Pauli Exclusion principal which prevents two electrons taking up the same quantum states. When matter is in the electron-degenerate state, all of the electrons are packed as closely as they can be in their quantum states. If the mass of the star is greater, electron degeneracy pressure is no longer sufficient. The elctrons are pushed into the atomic nuclei of the star's matter converting all the protons to neutrons. The star has now become a neutron star and is supported by neutron degeneracy pressure. If the mass is greater than a certain amount (can't remember, about 5 solar masses?) the star may become a quark star, but probably becomes a black hole.
Firstly, unused nuclear fuel is not very radioactive relatively speaking and is not very toxic.
Secondly, the fuel can (and is) built into very strong and resilliant "cans" and can be further protected to the point that even a fall from a great height such as earth-orbit will not result in any radioactive release.
Thirdly, any engineer woth their salt will design the darned thing such that it will not start its nuclear reactor (when the nasty fission products start to be produced) until the craft is either a significant distance away from earth already, or has achieved escape velocity and can not fall back to earth.
I am a qualified nuclear engineer with several years reactor physics experience at a nuclear power station.
No, I am definitely referring to photon pressure. High energy gamma rays are produced by the nuclear reactions in the stellar core. They collide with atoms on their way out, loosing energy (and momentum), exerting a net outwards force on the gas, and becoming longer wavelength (down to visible frequencies). On average, a photon takes a million years to work its way out of the stellar core.
Physicists have solved this problem. The idea has been about as long as quantum mechanics and relativity. The articles are wrong.
Ooops, I'm talking rubbish (at least the latter part): forget the "and hence a net push" part.
...and a solar sail is esentially the same thing : a lump of matter being pushed upon by radiation flowing outwards from the star.
Never mind whether the rocket's moving or not. There is no such thing as a perfect mirror. Some of the photon's energy will be lost when they strike the mirror, so the photons will be red-shifted in that way. They will be re-radiated with less energy (and hence momentum) than they hit the mirror with, hence a net "push" on the mirror.
Whe I was studying Astrophysics many years ago, we learned that photon pressure is what "keeps stars up" i.e. the pressure exerted by the photons produced in the star exerted on the matter comprising the star are what prevents it from collapsing under its own gravity. My mind is rusty, but we derived the equations and solved them for certain masses of stars. We also looked at solar sails using similar maths. I suspect that solar sailing is possible, since the physics is similar to what's going on inside a star...
In that case, the USA's days as the leading nation on earth (financially, technologically etc.) are numbered. As they choose to rest on their laurels, they will stagnate and then wither. It's sad to see the vitality disappear from what was once such a great country. Such short-sightedness will end in tears.
My ZX81 didn't have any colours at all, only black and white. It went black and blue when the TV set broke though. And at my last job, the computer didn't even have a CRT on the console. It had a teletype, and the ink had run out and they stopped making ribbons years ago. We had surgeons gloves and a bottle of Quink.
because 32-bit protected mode hardware wasn't available until the 80386 was released.
Which came out in 1985 if I am not mistaken. I remember the first 386 PCs in about 1987? Initially they ran at 14.6MHz (they were intended to run at 16MHz).
Like I said though, backwards compatability with old DOS apps (and having to use the BIOS) are what held back proper OSs. Oh well, maybe my memory has rotted away since then.
It depends how big the chunk is. Basically, the impact needs to accelerate the "chunk" form zero to escape velocity. Escape velocity is the same for everything (it only depends on the earth's mass and the distance from the centre of mass) but varies very very very slightly with height. How much of a push your chunk needs depends on its mass.
The PC might not have been technically superior to other machines of the era bot they had the adaptive edge of being an open infrastructure.
The IBM PC was never an open infrastructure. It was closed, however this is a common misconception nowadays. What actually happened is that people reverse-engineered the PC, documented it, and did a "clean-room" reimplementation to avoid litigation ie the implementors were not part of the reverse-engineering teams. This was especially important for the ROM BIOS of the PC which was essential for writing any sort of software in those days since MS-DOS was so limited (ie you gad to speak straigh to the BIOS). So if you didn't have an IBM-compatible BIOS you weren't "PC Compatible". You may have been able to run a port of MS-DOS though.
This was also one of the reasons it took so long for "real" operating systems to take of on PCs. The BIOS only worked in Real Mode and hardware was so disparate and open source hadn't been invented, so no one got around to writing a Protected Mode (32-bit) OS for a long time...
Why would it be inspirational? What would it inspire people to do?