Having your thesis/dissertation on file with your University might work. Most of those also get published, depending on your field.
Either way, having the information documented and dated is the thing you need to do. Having your presentation materials from those talks would help out as well.
And if you win, be sure to write a letter to the person trying to patent your idea saying, "SUCK IT, BITCH! SUCK IT HARD!"
Jim Forman cracked me up. I actually miss his stuff since moving to California.
"There's a pile of shit at 4th and Pine!"
"It's brown and about waist high!"
"We'll keep you updated. This is Jim Forman, King 5 News. Back to you Jean."
Ever notice how he always got stuck doing the crappiest stories? LOL.
That same embassy caught fire... as a result of an HPM weapon. This was done by the Russians so the KGB could get into the embassy and plant bugs and look at papers (they were disquised as firemen).
It would not be hard to give them laser-safe glasses. The military always uses maps with no red on them. How hard would it be to pick a color that no warning light in cockpit uses and swap it out on maps?
Pretty darn hard considering the fact that red is one of the colors that designates warning/danger in a cockpit. That comes from a MIL-STD and is enforced by the FAA. If you don't have your warning/danger items marked with red/yellow/orange, then you are not flying. Well, legally anyways.
That's why you'll see ejection seat handles with yellow on them, weapon fire controls as red, warning lights as red/orange/yellow, and altitude or collision warnings as red/orange/yellow.
Not quite. Otherwise, SSO couldn't use that neat trick of feathering its wings to get back down. It's just the type of wing that you use (airfoil shape, span, chord-length, twist, etc.) have to be changed to work at the particular dynamic pressures you are encountering. Basically, the wing should approach what looks like a flat plate as the density of your working fluid goes down (or stated another way, as the mean free path of your working fluids' particles goes UP). The flat plate will also have to increase in wing area to generate similar amounts of lift.
There is no definite boundary where lift is no longer created, or drag stops influencing your vehicle. Those things ALWAYS exist in space. Even farther away from the earth where you have a contant stream of particles moving outwards from the sun... make a large enough flat plate and you can generate some lift off of that "solar wind".
They are. Remember that big tax cut that Bush and the Republican Congress gave you? I guess you don't.
Nope. I don't remember any tax cut. I made 50K at my last job and had to pay 9310 in federal income tax.
I started a new job last March and will make about the same. My taxes are still going to be about 9310. Where was that tax break again?
You know what? I think my dad got a tax break from the previous year. It was $125. And he has made just a little under 50K for a while.
Instead of Bush writing out changes to give tax breaks to small businesses and upper income folks, he should put something down that eliminates taxes for folks that are at or below the poverty line for income. Then again, I suppose if you can tax 40 million people that are making less than 10,000 per year a dollar each, you've just acquired 40 million dollars. *snicker*
You know, before about 1930 the US taxed only the rich. Many people had small businesses, people were generally happy (minus the occasional labor riot), and the government ran itself just fine. I can understand that WWII changed a lot of things, such as changed congress' mind about the middle class, but the system could be better if it were more fair. Taxing only the rich doesn't make sense, because it could drive the rich away. Taxing the poor doesn't make sense for obvious reasons. Taxing the mostly the middle class puts the burden on the majority of the people, but it also creates some unrest.
The best thing to do would be to push for a tax schedule that scales with what you earn, instead of stopping at 35% for people that make more than a couple a hundred thousand a year. Or make everyone pay 25% or 30% in taxes that earn over the poverty line for your area (scaled up as you move away from the poverty level, of course).
Cutting federal taxes, which sucks money promised away from local and state communities or federal programs, hurts the people still. Those people are paying higher property, income, or sales taxes to make up for the shortfall.
You don't really need sophisicated equipment. If you get a separate fiber right next to the one you're sniffing, the electric field can permeate the optical materials and carry over to the second fiber. The problem is knowing what the frequency is of the laser light. Then you have to select the proper dielectric in your second fiber.
And it's not the photons that are leaking, those don't escape the fiber. It's the electric field caused by the photons being transmitted through the fiber that you pick up. This can set up a strong enough electric field in the second fiber to propagate photons.
This is a method for measuring laser intensity through fiber optics without actually intercepting the photons. It's used in the study of light propagation in fiber optics.
Physical possession of a piece of property does not infer possession of any piece of spectrum that is on/through it; the spectrum in its entirety is public property administered by the FCC. "Ownership" of a part of the spectrum is actually a contract with the Federal Government in which the government guarantees prosecution of other entities utilizing that frequency in that geographic area. The FCC is the sole trier when it comes to disputes involving spectrum interference; they have administrative procedures established to deal with this. Surely your university is required to implement CFR and USC, which means that the university must seek remedy within the structure of that framework; eg if you have a complaint about interference, take it to the FCC.
Title 47, Chapter 5, Subchapter I, Section 151 would beg to differ with your statement that FCC regulations are not law.
Title 47 is from the US Code... a composition of the laws that are used to run the country.
In any case, the FCC does have the power to do whatever it wants with the electromagnetic spectrum, within reason (such as not going against the public interest).
In Section 151, it states that: "there is created a commission to be known as the ''Federal Communications Commission'', which shall be constituted as hereinafter provided, and which shall execute and enforce the provisions of this chapter".
Now... Title 47, Chapter 5, Subchapter III, Part 1, Section 302a, paragraph (f) states defines the "State and local enforcement of FCC regulations on use of citizens band radio equipment", that says that the FCC can enforce rules through law enforcement agencies for CB radio.
I am assumming with this specific mention of the FCC being able to enforce its regulations through law enforcement that the commission could enforce its regulations via law enforcement in other cases.
The FCC also has the ability to fine licensed radio operators.
Also, the ability of the FCC to regulate the EM spectrum is governed by the FCC's powers given to it from congress through application of the part of the Constitution concerning commerce between states, indian tribes, and foreign nations.
You are correct in that the students' equipment may not interfere with your school's equipment. That's one of those rules governing the use of home electronics. (FCC 15, part B, I think...). The device shall not cause interference... or something like that. Which limits both antenna length and power levels for the students' radio equipment.
Clauses of a contract don't apply where the law supercedes them.
Fine print can go to hell if say, a local, state, or federal law specifically grants you a right and the contract says you can't use that right.
For example, say a renter gets a note from his land-lord that the land-lord will show his apartment in five minutes. The renter can say hell no, and be perfectly within the law. Even if the rental agreement specifically states that the land-lord can enter the premises with "a warning" or can show the apartment "at reasonable hours".
At least, that's the case in most states. And it makes those parts of the contract null and void.
The same idea applies here; because the equipment uses the electromagnetic spectrum, the FCC and only the FCC has regulatory power in the United States. Even the US military has to obtain permission from the FCC for military bands.
IANAL, but I play one on TV. But I know for a fact that the FCC has won at least one case in the past where a company said that people couldn't use a certain frequency due to a contract, but that company didn't own the license for that frequency.
Now, as owner of the school's network, the school can block access from that room on the school's end. But they can't physically disconnect the WAP. The students have the right to setup whatever they want in their room as long as it's not illegal. A contract saying that they couldn't put daiseys in a vase in their room is void. (Unless those daiseys are flesh-eating plants that walk. Then that's a threat to student safety and school property.)
I might needd to check my math history a bit, but I can't think of any major mathematics which were developed for a specific practical purpose since about Gauss.
Well, the Finite Element Method and the resulting analytical techniques were developed int he 1950's at the University of Washington. That type of analytical math is used for dynamic modeling of structures, fluids, electronics, and a few other things. It's calculus of variations at its core, but a more powerful technique in its field.
A better example would be statistics. Most any cutting edge physics involves statistics in some way. Statistics is also the basis for quantum mechanics.
As for Perelman's results, it can be summarized as follows:
Any 3-dimensional surface is made of a superposition of surfaces with loops, and those without loops. (Looped surfaces means that a coffee cup and a torus are the same.)
Out of all the 3-dimensional surfaces known, only the sphere is the simplest.
All surfaces in 3-dimensions consist of a sphere and any combination of looped surfaces. Open surfaces are not included in this new definition.
That last was Poincare's conjecture. Perelman proved that the simplest object in 3-dimensions is a sphere, and successively more complex surfaces are made of a sphere superposed with looped surfaces (donuts).
What this all means for the rest of us? Not much, other than physics has a more stable foundation in math (for 3-dimensions.)
As we currently understand atomic physics, that would be the case.
The ratio of iron to fissionable elements is pretty big; in other words, there is much more iron than fissionable materials.
Much of the initial heating of the earth was from compression of the stuff that the planet is made of. Most of that heat was trapped inside, and allowed the most common, dense materials to slowly sink to the center. Because of pressure, the core is believed to be a semi-solid oblong sphere of iron and nickel, with a liquid mantle surrounding the core.
There are enough radioactive materials that they do provide some heating. Most of the heat input is caused by friction which arises from the stresses caused by the moon and sun. But the amount of heat input from friction and radioactive decay is extremely tiny compared to the amount of heat stored in the liquified and semi-solid material inside the earth.
OK, if its density is doubled -- i.e., it's all nickel-iron -- then radius is halved, and gravitation squared, you'd get ~9G. There's no way you'd get enough extra compression to bump the gravity to 14G. (Remember the iron in Earth's core is under great pressure already.) You would need to admix uranium or something, as I noted earlier.
Under normal pressures, U is a little more than twice as dense as Fe, and might be a little more compressible; figure 2.5. Then, you get 9 * 2.5 * 2.5 = 56G for a solid uranium planet of 14 Earth masses
Then you came along and pointed out that:
... you can't compress uranium much more than it already is.
Au contraire, compression is one of the ways that very sub-critical masses of fissionables are turned into bombs (neutron reflectors are another). Peak densities are several times the STP solid density. [google.com] Perhaps you never wondered why implosion designs are used for nuclear weapons; that's one reason.
So let's see, we need to pack 56 earth masses into 8 earth volumes. Going from rock to nickel-iron gets you a factor of 2.4 or so, which yields 19.2 masses; if the heat of formation helped to boil off the materials of lower density it wouldn't surprise me. Could compression push the density up by another factor of 3? If conventional explosives can do it in a small package, it seems likely. Are there any high-pressure physicists who can offer a pointer to research here?
My text in bold. You can't compress things denser than iron without running into unstable elements being made. As I noted. You can make a fission bomb out of anything that is more dense than iron, but with most of those elements, it will take a lot more energy to sustain the fission reaction than if you chose one of the more highly radioactive ones. When you get to the other side of iron, the energy yeilded from a fission reaction is never enough to sustain it (fast nuetrons can not be produced fast enough).
That's how my statement was relevant.
As for compressing uranium in the case of a planet having a uranium core, you could do it up to a point. Once you pass a certain mass, the planet is essentially becomes unstable because compression is driving the naturally occuring nuclear reactions to create more than enough fast neutrons that it doesn't matter how much U238 you have in there. The mass will eventually explode from heat if it continues to be compressed, or the mass will radiate energy as it transmutates into elements with different (lower) atomic masses. Eventually the entire planet's mass will reach equilibrium and you'll have a gaussian distribution of elements, with a center probably around lead and its neighbors. You can't compress uranium too much, otherwise it will get too hot. As I said in the great-great-great-grandparent post, "If most of the planet is solid nickel-iron, rather than the percentage earth is, then I could see 14g's at the surface."
As for the planet having 3x the compression with twice the mass, most definitely. The equation that you would use to figure this out is similar the hydrostatic equation. You would integrate that over the volume of a sphere to get the force distribution of the matter in the sphere. IIRC, your pressure (compression) would increase linearly with depth. That compression would also heat up the material and you'd get a Rayleigh-Taylor instability if the material below liquified due to the heat. (More dense material (solid) on top of a less dense material (liquid).) You'd end up with a similar situation as what earth has with its tectonic plates. But that's only if the planet's mass is heated enough during compression. And judging from the distance from its parent star, I'd say that there is a significant heat input, so the planet more than likely has a scenario that is like plate tectonics.
Anything except hydrogen is fissionable. It's just that your energy approaches infinity as you try to do fission on elements on the hydrogen-iron curve. Iron is indeed fissionable, it just takes more energy to split it than you would get out.
Au contraire, compression is one of the ways that very sub-critical masses of fissionables are turned into bombs (neutron reflectors are another). Peak densities are several times the STP solid density. [google.com] Perhaps you never wondered why implosion designs are used for nuclear weapons; that's one reason.
Exactly the reason you'd not see a planet made of the stuff. Your cross-sections are just too high; meaning your chances of a neutron escaping one atom and hitting another that much more likely. Once you get past a certain mass, you've created a bomb.
From your link:
It would seem that the lower density delta phase has offsetting disadvantages in a bomb, where high density translates into improved efficiency and reduced material requirements, but this turns out not to be so. Delta stabilized plutonium undergoes a phase transition to the alpha state at relatively low pressures (tens of kilobars, i.e. tens of thousands of atmospheres).
Meaning that they used a high density version of pure plutonium because they could get away with less than the critical mass. The extra "mass" needed to initiate the reaction came from the high explosives used to implode the spheriod of plutonium and the shock heating such explosive lenses create.
First, you assume that the material is nickel-iron. It could be mostly osmium for all you know.
Second, if you double the density, the radius doesn't necessarily change. Which means that instead of 1 kg/m^3 of material you have 2 kg/m^3 of material. Which in turn means that the gravitational acceleration will double. As in a_gravity/m1 = G * M_planet / radius_planet^2. The radius doesn't change, G is a constant, but M_planet is twice as much. Thus you have twice as much acceleration.
If most of the planet is solid nickel-iron, rather than the percentage earth is, then I could see 14 g's at the surface.
Also, you can't compress uranium much more than it already is. That's how nuclear explosions occur. Plus, there is a limit to how much uranium you can pack into a space before nuclear reactions start to cascade. It's also most likely that the planet is made of mostly iron because that's where nuclear reaction rates are at their lowest; you can fuse stuff from hydrogen to iron, before it takes too much energy to fuse stuff, and you can split things from the high atomic numbers down to iron before it gets too hard. Iron is at the bottom of that curve.
The F16 gear can retract on the ground. The nose gear especially. I've also seen several other plane's gears be retracted on the ground. On pilot retracted his gear because he bumped the lever inside the cockpit... I think he sneezed or something and it knocked the lever. He was flying a cessna, if my memory serves.
And the next guy down is correct, squat switches fail all the time.
The article talks about making bulk quantities of the alumina glass. The researchers aren't given credit for discovering transparent metals, they are given credit for coming up with a means of manufacturing the materials in a more cost-effective manner.
Slashdot Mirror
Having your thesis/dissertation on file with your University might work. Most of those also get published, depending on your field.
Either way, having the information documented and dated is the thing you need to do. Having your presentation materials from those talks would help out as well.
And if you win, be sure to write a letter to the person trying to patent your idea saying, "SUCK IT, BITCH!
SUCK IT HARD!"
Isn't it "Danny Crane"?
Jim Forman cracked me up. I actually miss his stuff since moving to California.
"There's a pile of shit at 4th and Pine!"
"It's brown and about waist high!"
"We'll keep you updated. This is Jim Forman, King 5 News. Back to you Jean."
Ever notice how he always got stuck doing the crappiest stories? LOL.
That same embassy caught fire... as a result of an HPM weapon. This was done by the Russians so the KGB could get into the embassy and plant bugs and look at papers (they were disquised as firemen).
It would not be hard to give them laser-safe glasses. The military always uses maps with no red on them. How hard would it be to pick a color that no warning light in cockpit uses and swap it out on maps?
Pretty darn hard considering the fact that red is one of the colors that designates warning/danger in a cockpit. That comes from a MIL-STD and is enforced by the FAA. If you don't have your warning/danger items marked with red/yellow/orange, then you are not flying. Well, legally anyways.
That's why you'll see ejection seat handles with yellow on them, weapon fire controls as red, warning lights as red/orange/yellow, and altitude or collision warnings as red/orange/yellow.
Not quite. Otherwise, SSO couldn't use that neat trick of feathering its wings to get back down. It's just the type of wing that you use (airfoil shape, span, chord-length, twist, etc.) have to be changed to work at the particular dynamic pressures you are encountering. Basically, the wing should approach what looks like a flat plate as the density of your working fluid goes down (or stated another way, as the mean free path of your working fluids' particles goes UP). The flat plate will also have to increase in wing area to generate similar amounts of lift.
There is no definite boundary where lift is no longer created, or drag stops influencing your vehicle. Those things ALWAYS exist in space. Even farther away from the earth where you have a contant stream of particles moving outwards from the sun... make a large enough flat plate and you can generate some lift off of that "solar wind".
They are. Remember that big tax cut that Bush and the Republican Congress gave you? I guess you don't.
Nope. I don't remember any tax cut. I made 50K at my last job and had to pay 9310 in federal income tax.
I started a new job last March and will make about the same. My taxes are still going to be about 9310. Where was that tax break again?
You know what? I think my dad got a tax break from the previous year. It was $125. And he has made just a little under 50K for a while.
Instead of Bush writing out changes to give tax breaks to small businesses and upper income folks, he should put something down that eliminates taxes for folks that are at or below the poverty line for income. Then again, I suppose if you can tax 40 million people that are making less than 10,000 per year a dollar each, you've just acquired 40 million dollars. *snicker*
You know, before about 1930 the US taxed only the rich. Many people had small businesses, people were generally happy (minus the occasional labor riot), and the government ran itself just fine. I can understand that WWII changed a lot of things, such as changed congress' mind about the middle class, but the system could be better if it were more fair. Taxing only the rich doesn't make sense, because it could drive the rich away. Taxing the poor doesn't make sense for obvious reasons. Taxing the mostly the middle class puts the burden on the majority of the people, but it also creates some unrest.
The best thing to do would be to push for a tax schedule that scales with what you earn, instead of stopping at 35% for people that make more than a couple a hundred thousand a year. Or make everyone pay 25% or 30% in taxes that earn over the poverty line for your area (scaled up as you move away from the poverty level, of course).
Cutting federal taxes, which sucks money promised away from local and state communities or federal programs, hurts the people still. Those people are paying higher property, income, or sales taxes to make up for the shortfall.
Also, to support my other statement, here is an experiment on modelocking:
u lding.pdf
http://www.amath.washington.edu/~kutz/kristin_spa
Note that the ring laser is pumped via another fiber coupled to it with a separate material.
You don't really need sophisicated equipment. If you get a separate fiber right next to the one you're sniffing, the electric field can permeate the optical materials and carry over to the second fiber. The problem is knowing what the frequency is of the laser light. Then you have to select the proper dielectric in your second fiber.
And it's not the photons that are leaking, those don't escape the fiber. It's the electric field caused by the photons being transmitted through the fiber that you pick up. This can set up a strong enough electric field in the second fiber to propagate photons.
This is a method for measuring laser intensity through fiber optics without actually intercepting the photons. It's used in the study of light propagation in fiber optics.
Hey, you sound like you'll be a good parent when the time comes.
Yes. But it would put a lot of resources into ways of breaking it.
Physical possession of a piece of property does not infer possession of any piece of spectrum that is on/through it; the spectrum in its entirety is public property administered by the FCC. "Ownership" of a part of the spectrum is actually a contract with the Federal Government in which the government guarantees prosecution of other entities utilizing that frequency in that geographic area. The FCC is the sole trier when it comes to disputes involving spectrum interference; they have administrative procedures established to deal with this. Surely your university is required to implement CFR and USC, which means that the university must seek remedy within the structure of that framework; eg if you have a complaint about interference, take it to the FCC.
Very well said by the AC.
Title 47, Chapter 5, Subchapter I, Section 151 would beg to differ with your statement that FCC regulations are not law.
Title 47 is from the US Code... a composition of the laws that are used to run the country.
In any case, the FCC does have the power to do whatever it wants with the electromagnetic spectrum, within reason (such as not going against the public interest).
In Section 151, it states that: "there is created a commission to be known as the ''Federal Communications Commission'', which shall be constituted as hereinafter provided, and which shall execute and enforce the provisions of this chapter".
Now... Title 47, Chapter 5, Subchapter III, Part 1, Section 302a, paragraph (f) states defines the "State and local enforcement of FCC regulations on use of citizens band radio equipment", that says that the FCC can enforce rules through law enforcement agencies for CB radio.
I am assumming with this specific mention of the FCC being able to enforce its regulations through law enforcement that the commission could enforce its regulations via law enforcement in other cases.
The FCC also has the ability to fine licensed radio operators.
Also, the ability of the FCC to regulate the EM spectrum is governed by the FCC's powers given to it from congress through application of the part of the Constitution concerning commerce between states, indian tribes, and foreign nations.
You are correct in that the students' equipment may not interfere with your school's equipment. That's one of those rules governing the use of home electronics. (FCC 15, part B, I think...). The device shall not cause interference... or something like that. Which limits both antenna length and power levels for the students' radio equipment.
The US military bands are regulated by the FCC as well.
Clauses of a contract don't apply where the law supercedes them.
Fine print can go to hell if say, a local, state, or federal law specifically grants you a right and the contract says you can't use that right.
For example, say a renter gets a note from his land-lord that the land-lord will show his apartment in five minutes. The renter can say hell no, and be perfectly within the law. Even if the rental agreement specifically states that the land-lord can enter the premises with "a warning" or can show the apartment "at reasonable hours".
At least, that's the case in most states. And it makes those parts of the contract null and void.
The same idea applies here; because the equipment uses the electromagnetic spectrum, the FCC and only the FCC has regulatory power in the United States. Even the US military has to obtain permission from the FCC for military bands.
IANAL, but I play one on TV. But I know for a fact that the FCC has won at least one case in the past where a company said that people couldn't use a certain frequency due to a contract, but that company didn't own the license for that frequency.
Now, as owner of the school's network, the school can block access from that room on the school's end. But they can't physically disconnect the WAP. The students have the right to setup whatever they want in their room as long as it's not illegal. A contract saying that they couldn't put daiseys in a vase in their room is void. (Unless those daiseys are flesh-eating plants that walk. Then that's a threat to student safety and school property.)
Gotta love how the nuclear storage containers at Hanford in Washington State still work today...
hanford leaks
And cleanup of the waste is not cheap...
cleanup
I might needd to check my math history a bit, but I can't think of any major mathematics which were developed for a specific practical purpose since about Gauss.
Well, the Finite Element Method and the resulting analytical techniques were developed int he 1950's at the University of Washington. That type of analytical math is used for dynamic modeling of structures, fluids, electronics, and a few other things. It's calculus of variations at its core, but a more powerful technique in its field.
A better example would be statistics. Most any cutting edge physics involves statistics in some way. Statistics is also the basis for quantum mechanics.
As for Perelman's results, it can be summarized as follows:
Any 3-dimensional surface is made of a superposition of surfaces with loops, and those without loops. (Looped surfaces means that a coffee cup and a torus are the same.)
Out of all the 3-dimensional surfaces known, only the sphere is the simplest.
All surfaces in 3-dimensions consist of a sphere and any combination of looped surfaces. Open surfaces are not included in this new definition.
That last was Poincare's conjecture. Perelman proved that the simplest object in 3-dimensions is a sphere, and successively more complex surfaces are made of a sphere superposed with looped surfaces (donuts).
What this all means for the rest of us? Not much, other than physics has a more stable foundation in math (for 3-dimensions.)
As we currently understand atomic physics, that would be the case.
;)
The ratio of iron to fissionable elements is pretty big; in other words, there is much more iron than fissionable materials.
Much of the initial heating of the earth was from compression of the stuff that the planet is made of. Most of that heat was trapped inside, and allowed the most common, dense materials to slowly sink to the center. Because of pressure, the core is believed to be a semi-solid oblong sphere of iron and nickel, with a liquid mantle surrounding the core.
There are enough radioactive materials that they do provide some heating. Most of the heat input is caused by friction which arises from the stresses caused by the moon and sun. But the amount of heat input from friction and radioactive decay is extremely tiny compared to the amount of heat stored in the liquified and semi-solid material inside the earth.
And uh... no comment on who my employer is.
I was replying to this person..
... you can't compress uranium much more than it already is.
OK, if its density is doubled -- i.e., it's all nickel-iron -- then radius is halved, and gravitation squared, you'd get ~9G. There's no way you'd get enough extra compression to bump the gravity to 14G. (Remember the iron in Earth's core is under great pressure already.) You would need to admix uranium or something, as I noted earlier. Under normal pressures, U is a little more than twice as dense as Fe, and might be a little more compressible; figure 2.5. Then, you get 9 * 2.5 * 2.5 = 56G for a solid uranium planet of 14 Earth masses
Then you came along and pointed out that:
Au contraire, compression is one of the ways that very sub-critical masses of fissionables are turned into bombs (neutron reflectors are another). Peak densities are several times the STP solid density. [google.com] Perhaps you never wondered why implosion designs are used for nuclear weapons; that's one reason. So let's see, we need to pack 56 earth masses into 8 earth volumes. Going from rock to nickel-iron gets you a factor of 2.4 or so, which yields 19.2 masses; if the heat of formation helped to boil off the materials of lower density it wouldn't surprise me. Could compression push the density up by another factor of 3? If conventional explosives can do it in a small package, it seems likely. Are there any high-pressure physicists who can offer a pointer to research here?
My text in bold. You can't compress things denser than iron without running into unstable elements being made. As I noted. You can make a fission bomb out of anything that is more dense than iron, but with most of those elements, it will take a lot more energy to sustain the fission reaction than if you chose one of the more highly radioactive ones. When you get to the other side of iron, the energy yeilded from a fission reaction is never enough to sustain it (fast nuetrons can not be produced fast enough).
That's how my statement was relevant.
As for compressing uranium in the case of a planet having a uranium core, you could do it up to a point. Once you pass a certain mass, the planet is essentially becomes unstable because compression is driving the naturally occuring nuclear reactions to create more than enough fast neutrons that it doesn't matter how much U238 you have in there. The mass will eventually explode from heat if it continues to be compressed, or the mass will radiate energy as it transmutates into elements with different (lower) atomic masses. Eventually the entire planet's mass will reach equilibrium and you'll have a gaussian distribution of elements, with a center probably around lead and its neighbors. You can't compress uranium too much, otherwise it will get too hot. As I said in the great-great-great-grandparent post, "If most of the planet is solid nickel-iron, rather than the percentage earth is, then I could see 14g's at the surface."
As for the planet having 3x the compression with twice the mass, most definitely. The equation that you would use to figure this out is similar the hydrostatic equation. You would integrate that over the volume of a sphere to get the force distribution of the matter in the sphere. IIRC, your pressure (compression) would increase linearly with depth. That compression would also heat up the material and you'd get a Rayleigh-Taylor instability if the material below liquified due to the heat. (More dense material (solid) on top of a less dense material (liquid).) You'd end up with a similar situation as what earth has with its tectonic plates. But that's only if the planet's mass is heated enough during compression. And judging from the distance from its parent star, I'd say that there is a significant heat input, so the planet more than likely has a scenario that is like plate tectonics.
au contrare...
Anything except hydrogen is fissionable. It's just that your energy approaches infinity as you try to do fission on elements on the hydrogen-iron curve. Iron is indeed fissionable, it just takes more energy to split it than you would get out.
Au contraire, compression is one of the ways that very sub-critical masses of fissionables are turned into bombs (neutron reflectors are another). Peak densities are several times the STP solid density. [google.com] Perhaps you never wondered why implosion designs are used for nuclear weapons; that's one reason.
Exactly the reason you'd not see a planet made of the stuff. Your cross-sections are just too high; meaning your chances of a neutron escaping one atom and hitting another that much more likely. Once you get past a certain mass, you've created a bomb.
From your link:
It would seem that the lower density delta phase has offsetting disadvantages in a bomb, where high density translates into improved efficiency and reduced material requirements, but this turns out not to be so. Delta stabilized plutonium undergoes a phase transition to the alpha state at relatively low pressures (tens of kilobars, i.e. tens of thousands of atmospheres).
Meaning that they used a high density version of pure plutonium because they could get away with less than the critical mass. The extra "mass" needed to initiate the reaction came from the high explosives used to implode the spheriod of plutonium and the shock heating such explosive lenses create.
First, you assume that the material is nickel-iron. It could be mostly osmium for all you know.
Second, if you double the density, the radius doesn't necessarily change. Which means that instead of 1 kg/m^3 of material you have 2 kg/m^3 of material. Which in turn means that the gravitational acceleration will double. As in a_gravity/m1 = G * M_planet / radius_planet^2. The radius doesn't change, G is a constant, but M_planet is twice as much. Thus you have twice as much acceleration.
If most of the planet is solid nickel-iron, rather than the percentage earth is, then I could see 14 g's at the surface.
Also, you can't compress uranium much more than it already is. That's how nuclear explosions occur. Plus, there is a limit to how much uranium you can pack into a space before nuclear reactions start to cascade. It's also most likely that the planet is made of mostly iron because that's where nuclear reaction rates are at their lowest; you can fuse stuff from hydrogen to iron, before it takes too much energy to fuse stuff, and you can split things from the high atomic numbers down to iron before it gets too hard. Iron is at the bottom of that curve.
The F16 gear can retract on the ground. The nose gear especially. I've also seen several other plane's gears be retracted on the ground. On pilot retracted his gear because he bumped the lever inside the cockpit... I think he sneezed or something and it knocked the lever. He was flying a cessna, if my memory serves.
And the next guy down is correct, squat switches fail all the time.
I hope they don't wise up and require all passengers to travel naked with no luggage. Hmm, second thought..that could be interesting ;)
Until that fat lady sits down next to you, taking up TWO seats, and part of her fat rolls onto your lap.
I've seen too many fat people flying in one seat, when they obviously need two, to want to see everyone on a flight naked.
The article talks about making bulk quantities of the alumina glass. The researchers aren't given credit for discovering transparent metals, they are given credit for coming up with a means of manufacturing the materials in a more cost-effective manner.