The suits aren't a perfect insulator, and no one has a perfect insulator yet.
Man goes into suit. Suit goes into space.
A pretty total vacuum's in space. Vacuum's a pretty damned good insulator. The only way to cool things off in that environment is radiative cooling, unless you wanna also cart along a lot of some working fluid to boil off. Radiative cooling's damned inefficient. Take a human being, who's going to be generating more than 100 W if he's going any kind of useful work, and put him in a medium which precludes any cooling except radiative, and watch him overheat and die in pretty short order. The parent is right: the spacesuit's a lot more about cooling the astronaut than it is about heating him.
Your blood won't boil? Bullshit
You're a Hollywood-trained idiot. Your blood will not boil. Your body will not explode. There will be outgassing, but not so much as you think, and that's not the same thing as *boiling*, anyway; would you say that a deep-sea diver who ascends too fast ends up with his blood boiling? Of course you wouldn't, because outgassing isn't the same thing as boiling.
The temperature things boil at depends quite a bit on pressure.
Why, yes, yes it does.
How the hell do you think that rubber glove works? It works by *maintaining pressure*.
And how do you think it does that? Why, because it's elastic, right?
Gee, what else is elastic? I know! The human body!
For more information look into the bnetd court case.
For contrary information, look into Softman v. Adobe, in which the court found that what occurred was a sale, and not a license, regardless of the fact that Adobe really really wanted to treat it as a license.
Right now, you don't worry much about crossing the street against the light. The odds that you'll be struck and killed by a car you missed are pretty small, even when you take into account just how many times you jaywalk.
If you live forever, however, eventually you'll be hit and killed.
Assuming immortals still drive cars. I wouldn't; even with a very small chance to be involved in a fatal crash, per mile driven, eventually the Law of Large Numbers will catch up with me and I'll die behind the wheel. No thanks.
Behavior that's an acceptable level of risk over the course of a normal lifespan becomes unacceptable as lifespans increase.
asers usually do NOT divergent (or only a very little), thats exactly what makes a laser different from normal light.
What makes a laser different from normal light is that it is coherent and monochromatic.
Uncollimated laser light obeys the inverse-square law. Even collimated laser light obeys it, it's just that you need to treat the initial range to the source as greater than it actually is - the 'source' of the beam isn't the exit lens, but is represented as a point behind that lens. The more collimated the beam, the further behind. Ferinstance, using numbers pulled right from my butt, if the beam divergence is 1 mrad, and the beam diameter at the exit lens is 1 mm, then the effective source of the light is a point one meter further away than the exit lens. If you then measure the beam intensity at 5 cm and 10 cm from the exit lens, it won't look like it's falling off as the inverse square, because the beam only widened by about 9%. But really, you didn't double the distance, you only increased it from 105 cm to 110 cm.
No, they're not. While insolation at 1AU from the sun is indeed about 1300 watts per square meter, that, or anything approaching it, can't be used as an average insolation value *anywhere* on the earth's surface.
In Albequerque, New Mexico, the yearly average (taking into account both day *and* night, when the sun doesn't shine at all), is actually only about 250 watts per square meter. So you're already off by a factor of 4. Move to a city like Seattle, which is a lot farther north (less sunlight) and where inclement weather is a lot more frequent than in Albequerque (less sunlight), and I wouldn't be surprised to see that you're off by a factor of 10. And if you can't recoup your capital investment before your solar cells and inverters (you completely ignored the cost of the other parts of the system other than the cells, by the way) need replacement, you're talking about a net loss - the system never pays for itself.
But that's *supposed* to happen. A hallmark of truly great art is that the reader can take things away from it that the author never put *into* it, apply it to situations which the author never even considered, and so forth.
Shakespeare almost certainly never put the consideration into almost every one of his lines that modern students study them with, but that's just an indication of the far-reaching and timeless nature of his work. "How should we stretch our eye when capital crimes, chewed swallowed and digested appear before us" was certainly not written with, say, lethal injection in mind, as a discourse of the death penalty as applied in modern societies, but the greatness of that scene in Henry V is that we can *use* it to gain insights into situations unenvisioned by the author.
What an artist intends is pretty much secondary to what audiences perceive. If the artist doesn't like it, he can go screw himself.
They're RLC circuits, tuned to resonate at a specific frequency. When a chunk of metal gets into the loop, it changes the overall inductance of the circuit, and thus the resonant frequency changes. That change is what's picked up by the control box, and it changes the light.
For you folks with bicycles, try laying them down flat inside the loop.
Probably the best is to electrolyze it from water using electricity provided by solar power or another clean means of power.
That's probably the most expensive means possible.
Steven Den Beste provides some good numbers on this use-solar-power-to-crack-water suggestion:
In 1998, the State of California consumed 13.496 billion gallons of gasoline. A gallon of gasoline yields about 130 million joules. So when you do all the math, you end up with about 1.755 * 1018 joules, which is an impressively large number.
One anti-solar-power advocacy site gives the "yearly average" solar power density in Albuquerque as 240 watts per m2. (That appears to be a 24-hour average; another site says that it's 700 watts in daylight.) Then presuming that southern California is similar, each square meter of mirrors would be struck by 7.573 billion joules per year.
So if you assume 100% conversion, you'd need 231.7 million square meters of collection mirrors to make this work. 231 square kilometers.
But it isn't going to be 100% efficient. That's impossible, and it isn't going to be remotely close to that. The mirrors won't reflect perfectly and some of the sunlight will heat the metal instead of reflecting. The conversion process into hydrogen will be extremely inefficient. If you get 10%, you'll be doing really well.
So we're talking about paving 2300 square kilometers of California desert with mirrors. That's a strip 13 kilometers wide stretching from San Diego to Los Angeles. It's an area twice the size of San Francisco.
That's a hell of a lot of metal! It ain't gonna be cheap. The capital expense involved would be mammoth. Just clearing an area that large would cost a fortune; paving it with manufactured goods will cost a fortune. And something that big would take decades to build.
Figure each mirror at 10 square meters, and you're talking about 23 million motor mounts. If you figure an average 5 year lifespan, then you're going to replace more than 4 million of them per year.
Read the rest of it. Nuclear? Sure. But solar's just not feasible for this kind of scale.
If you're for democracy, why would you give a vote to a dictator?
That makes no sense. It seems that if "you're either for democracy or not," and you're for democracy, then you can't support giving the vote to the mullahs who rule Iran, or the despots in control of Sudan, or any of the various other dictatorial, despotic regimes the world over.
And yet that's exactly what the UN does. So if "you're either for democracy or not," then the only available conclusion is that the UN isn't for democracy.
he UN is obsolote because all power rests in the hands of the Security Council, and the power there lies only in the hands of the countries that hold veto power (US, UK, France, China, Russia).
Oh, I see. The problem is that backwards-assed medievalism as embodied in nations like Sudan and Iran isn't given enough power to wield on the world stage.
FSVO 'success.' The peacekeeping mission in Rwanda 'succeeded' by sitting there and let the butchers finish their work, and then claiming credit for halting the butchery. The peacekeeping mission in Somalia, didn't. The peacekeeping mission in Yugoslavia wouldn't have accomplished jack were it not for the US's willingness to spread peace, love, and understanding in 500, 1000, and 2000 lb packages.
Google on 'Srebrinica Massacre' to see what sort of security UN peacekeepers can provide.
The number of genocides that have taken place on the UN's watch is a travesty. The number that have taken place within weapons range of UN peacekeepers is an indictment.
And all those aid programs, haven't they also contributed to not just well-being, but also stability and peace in the world?
Stability and peace are often at cross-purposes with the 'well-being' of the world. UNICEF feeds kids who are starving because of their fucked-up governments, but doesn't do a thing to replace fucked-up governments that starve their own populations. The WHO works to eradicate disease in countries with fucked-up governments, but doesn't do a thing to replace the fucked-up governments that don't give a shit about the poor public health of their populace.
I'd even go as far as to say that what those organizations do every day around the world is the only way to effectively fight terrorism -- remove the causes.
And where, oh where, has the UN managed to accomplish this?
Has it ocurred to anyone that the reason the UN "can't get anything useful done" is that the US owes close to $600 Million in dues?
Yeah. That's it. The UN can't manage to pass a resolution condemning genocide in Darfur 'cause they can't afford the inkjet cartridges to print one up, or the copier toner to run off enough to hand out to the General Assembly.
It was created to do no such thing. It was created in order to prevent a third world war from occurring, with the Western democracies (the '1st world') on one side and the Soviet Union and its client states (the '2nd world') on the other.
This was a laudable goal, and to the extent that this did not happen, the UN achieved its goal. Like any other bureaucratic organization rendered obsolete by the passage of time, the UN has endeavoured to reinvent itself. Unfortunately, as the simple facts of the matter are that there exist more backwards, primitive, kleptocratic, oppressive governments than there exist enlightened democracies, the voice the UN speaks with is chiefly the voice of its basest and more numerous members.
Fer Chrissakes, Sudan, a government currently undergoing an organized campaign of genocide against its own citizenry,sits at the head of the UN Human Rights Commission. And what does the General Assembly do about such a travesty? It steadfastly refuses to pass a resolution condemning antisemitism.
That's pretty much the current UN in a nutshell. When it *does* manage to accomplish something, like imposing sanctions on Saddam Hussein, it ends up looting the Food for Oil program which was intended to spare the Iraqi people the worst impact of those sanctions.
It's a nest of vipers. It's not even that it's anti-American; I'm not arrogant enough to condemn such sentiment a priorily. But it's clearly anti-liberal, and I use that word in its classic Lockeian sense. The ideals that this country was founded on, that individual liberty is the highest goal for which one can struggle, are anathema to the Westphalian notions of national sovereignity that the UN was founded upon. If we do truly hold that governments derive their legitimacy from the consent of the governed, then how can we go about treating illegitimate governments to an equal seat at the table?
Nations like North Korea, Saudi Arabia, China, Singapore, and Iran make up a large part of the UN. There is no way in hell I want those countries having the merest degree of jurisdiction over what I can do, say, or read on the internet. The very suggestion is utter lunacy.
That's a remarkably accurate description of the UN itself. I mean, what can you say about an organization that places Sudan on its Human Rights Committee?
Oh, yeah, that's a really binding treaty, with significant powers of enforcement behind it:
Any State Party to the Treaty may give notice of its withdrawal from the Treaty one year after its entry into force by written notification to the Depositary Governments. Such withdrawal shall take effect one year from the date of receipt of this notification.
This is really nothing new. The USAF had an anti-satellite missile program decades ago, a two-stage rocket launched from an F-15 at high-altitude. There was one successful test, and the program was then shelved. The Soviet Union had an anti-satellite satellite, that if used would match orbits with the target, get close to it, and then detonate.
I like how this stuff only becomes Eeeeevul when the Bush administration looks into it.
Actually hydro power is pretty efecient if you have the resources.
It's also devastating to downstream ecologies. A major hydroelectric project like Three Gorges is an ecological disaster.
Without developing a breeder reactor the uranium will run out as well.
Okay, so develop a breeder reactor. Running in a breeder reactor, uranium would be economical at costs of $1,000 per pound (1983 dollars), and would contribute 0.03 cents per kilowatt-hour to the cost of electricity.
Or, don't develop a breeder reactor. Uranium could be extracted from seawater for far less than that, around $200-400 per pound, and there's enough of it currently in the oceans to supply the planet's current electrical needs for millions of years. Hell, if we extract 16,000 tons of it per year, that's enough to supply twice the world's energy consumption, 25 times its electrical demand.
Oil is expensive and will run out one day, hydrogen won't
Sure it will. It already has. The Earth's gravity isn't strong enough to retain hydrogen in the atmosphere.
Hydrogen simply does not exist in a free state. So to get hydrogen, you need to manufacture it.
This is done commercially via the reformation of hydrocarbons like natural gas. And, like you suggest, they'll run out.
You can also manufacture hydrogen through the electrolysis of water. This takes electricity. You get your electricity from burning fossil fuels, which like you suggest, will run out.
Unless you have a clean source of electricity to begin with, hydrogen-fueled cars aren't going to clean anything up, and they still rely on "a substance that will run out eventually."
Isn't gasoline pretty dangerous stuff? I mean, I know it's quite flammable. Does anyone remember the Happy Land fire?
Which brings my question - how do you stabilize gasoline so it's not so flammable? A car accident could spell disaster if not properly contained.
To be less sarcastic, c'mon. Cars drive around all day long with thin-walled steel 20-gallon tanks of flammable liquid hydrocarbon fuel, and they rarely rupture. Considering that to get useful vehicle ranges with hydrogen fuel, you need to have the fuel tank pressurized to several thousand psi, you're going to be making it out of rather thick steel with a helluva safety margin. Then there's the fact that hydrogen's a lot lighter than air, so if by some horrendous accident (which will involve energies more than sufficient to kill the vehicle occupants anyway) the tank does rupture, the hydrogen's going to head for the stratosphere as fast as bouyancy allows, instead of pooling on the pavement in flaming puddles.
The reactivity of hydrogen is a concern, but it's a small and easily-handled one. Where to get the hydrogen is a far larger issue.
If I remember correctly, the third phase is not enriched U235, but either natural or depleted uranium, the 238 isotope.
I explained that this bomb is not usual, and that the jacket is in fact U-235, as opposed to U-238.
U-238 *is* fissile. But the neutron has to have high energy.
Again, from my post to which you're responding: "U-238 won't sustain a chain reaction, but it'll fission merrily if you bombard it with fast neutrons."
These are produced by the fusion stage. So there is no need to use dangerous and expensive enriched uranium for the bomb casing.
The *point* is that at the time in which this bomb was designed, they did not have the hydrocodes to ensure efficient compression of the fusion stage using only the small primary trigger. So they made the casing from enriched uranium, so that they could be sure of igniting the fusion stage.
While it is currently fashionable to believe that the only terrorists in the world are those of middle-eastern descent or belief,
Name me a major terrorist attack since the OKC bombing that was not carried out by Islamic extremists.
there are enough home grown idiots with grudges against the government to go out there with the bass-boat, a winch and a case or two of beer.
If two good-ol' boys with a bass boat and a winch can manage to excavate a 7,000 bomb buried under decades worth of sediment, the Terrorists Have Already Won(tm).
Yeah, you're right, that was a quick WAG based on the overall weight of the bomb, which is like 7,000 pounds. 400 pounds of high explosive, roughly a critical mass of plutonium, all the support apparatus and structure, and the jacket.
Bad estimate. In Ivy King, 60 kilograms of HEU yielded 500 kilotons, so this one's probably around 150, 200 kilograms. Something like that.
Slashdot Mirror
The suits aren't a perfect insulator, and no one has a perfect insulator yet.
Man goes into suit. Suit goes into space.
A pretty total vacuum's in space. Vacuum's a pretty damned good insulator. The only way to cool things off in that environment is radiative cooling, unless you wanna also cart along a lot of some working fluid to boil off. Radiative cooling's damned inefficient. Take a human being, who's going to be generating more than 100 W if he's going any kind of useful work, and put him in a medium which precludes any cooling except radiative, and watch him overheat and die in pretty short order. The parent is right: the spacesuit's a lot more about cooling the astronaut than it is about heating him.
Your blood won't boil? Bullshit
You're a Hollywood-trained idiot. Your blood will not boil. Your body will not explode. There will be outgassing, but not so much as you think, and that's not the same thing as *boiling*, anyway; would you say that a deep-sea diver who ascends too fast ends up with his blood boiling? Of course you wouldn't, because outgassing isn't the same thing as boiling.
The temperature things boil at depends quite a bit on pressure.
Why, yes, yes it does.
How the hell do you think that rubber glove works? It works by *maintaining pressure*.
And how do you think it does that? Why, because it's elastic, right?
Gee, what else is elastic? I know! The human body!
Moron.
For more information look into the bnetd court case.
For contrary information, look into Softman v. Adobe, in which the court found that what occurred was a sale, and not a license, regardless of the fact that Adobe really really wanted to treat it as a license.
Risk evaluation would have to change.
Right now, you don't worry much about crossing the street against the light. The odds that you'll be struck and killed by a car you missed are pretty small, even when you take into account just how many times you jaywalk.
If you live forever, however, eventually you'll be hit and killed.
Assuming immortals still drive cars. I wouldn't; even with a very small chance to be involved in a fatal crash, per mile driven, eventually the Law of Large Numbers will catch up with me and I'll die behind the wheel. No thanks.
Behavior that's an acceptable level of risk over the course of a normal lifespan becomes unacceptable as lifespans increase.
asers usually do NOT divergent (or only a very little), thats exactly what makes a laser different from normal light.
What makes a laser different from normal light is that it is coherent and monochromatic.
Uncollimated laser light obeys the inverse-square law. Even collimated laser light obeys it, it's just that you need to treat the initial range to the source as greater than it actually is - the 'source' of the beam isn't the exit lens, but is represented as a point behind that lens. The more collimated the beam, the further behind. Ferinstance, using numbers pulled right from my butt, if the beam divergence is 1 mrad, and the beam diameter at the exit lens is 1 mm, then the effective source of the light is a point one meter further away than the exit lens. If you then measure the beam intensity at 5 cm and 10 cm from the exit lens, it won't look like it's falling off as the inverse square, because the beam only widened by about 9%. But really, you didn't double the distance, you only increased it from 105 cm to 110 cm.
No, they're not. While insolation at 1AU from the sun is indeed about 1300 watts per square meter, that, or anything approaching it, can't be used as an average insolation value *anywhere* on the earth's surface.
In Albequerque, New Mexico, the yearly average (taking into account both day *and* night, when the sun doesn't shine at all), is actually only about 250 watts per square meter. So you're already off by a factor of 4. Move to a city like Seattle, which is a lot farther north (less sunlight) and where inclement weather is a lot more frequent than in Albequerque (less sunlight), and I wouldn't be surprised to see that you're off by a factor of 10. And if you can't recoup your capital investment before your solar cells and inverters (you completely ignored the cost of the other parts of the system other than the cells, by the way) need replacement, you're talking about a net loss - the system never pays for itself.
But that's *supposed* to happen. A hallmark of truly great art is that the reader can take things away from it that the author never put *into* it, apply it to situations which the author never even considered, and so forth.
Shakespeare almost certainly never put the consideration into almost every one of his lines that modern students study them with, but that's just an indication of the far-reaching and timeless nature of his work. "How should we stretch our eye when capital crimes, chewed swallowed and digested appear before us" was certainly not written with, say, lethal injection in mind, as a discourse of the death penalty as applied in modern societies, but the greatness of that scene in Henry V is that we can *use* it to gain insights into situations unenvisioned by the author.
What an artist intends is pretty much secondary to what audiences perceive. If the artist doesn't like it, he can go screw himself.
Close.
They're RLC circuits, tuned to resonate at a specific frequency. When a chunk of metal gets into the loop, it changes the overall inductance of the circuit, and thus the resonant frequency changes. That change is what's picked up by the control box, and it changes the light.
For you folks with bicycles, try laying them down flat inside the loop.
That's probably the most expensive means possible.
Steven Den Beste provides some good numbers on this use-solar-power-to-crack-water suggestion:
Read the rest of it. Nuclear? Sure. But solar's just not feasible for this kind of scale.
I'm guessing because yellow is a primary in both additive (transparencies) and subtractive (regular printing) color schemes.
Please explain.
If you achieve the velocity sufficient to achieve orbit, then you've achieved the velocity sufficient to orbit twice. And three times. And 17 times.
I must be missing something.
There are no more CGNs or DLGNs in service.
Compressive strength != tensile strength.
If you're for democracy, why would you give a vote to a dictator?
That makes no sense. It seems that if "you're either for democracy or not," and you're for democracy, then you can't support giving the vote to the mullahs who rule Iran, or the despots in control of Sudan, or any of the various other dictatorial, despotic regimes the world over.
And yet that's exactly what the UN does. So if "you're either for democracy or not," then the only available conclusion is that the UN isn't for democracy.
he UN is obsolote because all power rests in the hands of the Security Council, and the power there lies only in the hands of the countries that hold veto power (US, UK, France, China, Russia).
Oh, I see. The problem is that backwards-assed medievalism as embodied in nations like Sudan and Iran isn't given enough power to wield on the world stage.
That makes such sense.
Most peace-keeping missions have succeeded.
FSVO 'success.' The peacekeeping mission in Rwanda 'succeeded' by sitting there and let the butchers finish their work, and then claiming credit for halting the butchery. The peacekeeping mission in Somalia, didn't. The peacekeeping mission in Yugoslavia wouldn't have accomplished jack were it not for the US's willingness to spread peace, love, and understanding in 500, 1000, and 2000 lb packages.
Google on 'Srebrinica Massacre' to see what sort of security UN peacekeepers can provide.
The number of genocides that have taken place on the UN's watch is a travesty. The number that have taken place within weapons range of UN peacekeepers is an indictment.
And all those aid programs, haven't they also contributed to not just well-being, but also stability and peace in the world?
Stability and peace are often at cross-purposes with the 'well-being' of the world. UNICEF feeds kids who are starving because of their fucked-up governments, but doesn't do a thing to replace fucked-up governments that starve their own populations. The WHO works to eradicate disease in countries with fucked-up governments, but doesn't do a thing to replace the fucked-up governments that don't give a shit about the poor public health of their populace.
I'd even go as far as to say that what those organizations do every day around the world is the only way to effectively fight terrorism -- remove the causes.
And where, oh where, has the UN managed to accomplish this?
of course they'll always be in the minority
Read down a list of the UN general assembly.
They're not in the minority.
Has it ocurred to anyone that the reason the UN "can't get anything useful done" is that the US owes close to $600 Million in dues?
Yeah. That's it. The UN can't manage to pass a resolution condemning genocide in Darfur 'cause they can't afford the inkjet cartridges to print one up, or the copier toner to run off enough to hand out to the General Assembly.
The UN was created to unite countries,
,sits at the head of the UN Human Rights Commission. And what does the General Assembly do about such a travesty? It steadfastly refuses to pass a resolution condemning antisemitism.
It was created to do no such thing. It was created in order to prevent a third world war from occurring, with the Western democracies (the '1st world') on one side and the Soviet Union and its client states (the '2nd world') on the other.
This was a laudable goal, and to the extent that this did not happen, the UN achieved its goal. Like any other bureaucratic organization rendered obsolete by the passage of time, the UN has endeavoured to reinvent itself. Unfortunately, as the simple facts of the matter are that there exist more backwards, primitive, kleptocratic, oppressive governments than there exist enlightened democracies, the voice the UN speaks with is chiefly the voice of its basest and more numerous members.
Fer Chrissakes, Sudan, a government currently undergoing an organized campaign of genocide against its own citizenry
That's pretty much the current UN in a nutshell. When it *does* manage to accomplish something, like imposing sanctions on Saddam Hussein, it ends up looting the Food for Oil program which was intended to spare the Iraqi people the worst impact of those sanctions.
It's a nest of vipers. It's not even that it's anti-American; I'm not arrogant enough to condemn such sentiment a priorily. But it's clearly anti-liberal, and I use that word in its classic Lockeian sense. The ideals that this country was founded on, that individual liberty is the highest goal for which one can struggle, are anathema to the Westphalian notions of national sovereignity that the UN was founded upon. If we do truly hold that governments derive their legitimacy from the consent of the governed, then how can we go about treating illegitimate governments to an equal seat at the table?
Nations like North Korea, Saudi Arabia, China, Singapore, and Iran make up a large part of the UN. There is no way in hell I want those countries having the merest degree of jurisdiction over what I can do, say, or read on the internet. The very suggestion is utter lunacy.
a haven for suspected war criminals.
That's a remarkably accurate description of the UN itself. I mean, what can you say about an organization that places Sudan on its Human Rights Committee?
This is really nothing new. The USAF had an anti-satellite missile program decades ago, a two-stage rocket launched from an F-15 at high-altitude. There was one successful test, and the program was then shelved. The Soviet Union had an anti-satellite satellite, that if used would match orbits with the target, get close to it, and then detonate.
I like how this stuff only becomes Eeeeevul when the Bush administration looks into it.
Actually hydro power is pretty efecient if you have the resources.
It's also devastating to downstream ecologies. A major hydroelectric project like Three Gorges is an ecological disaster.
Without developing a breeder reactor the uranium will run out as well.
Okay, so develop a breeder reactor. Running in a breeder reactor, uranium would be economical at costs of $1,000 per pound (1983 dollars), and would contribute 0.03 cents per kilowatt-hour to the cost of electricity.
Or, don't develop a breeder reactor. Uranium could be extracted from seawater for far less than that, around $200-400 per pound, and there's enough of it currently in the oceans to supply the planet's current electrical needs for millions of years. Hell, if we extract 16,000 tons of it per year, that's enough to supply twice the world's energy consumption, 25 times its electrical demand.
Oil is expensive and will run out one day, hydrogen won't
Sure it will. It already has. The Earth's gravity isn't strong enough to retain hydrogen in the atmosphere.
Hydrogen simply does not exist in a free state. So to get hydrogen, you need to manufacture it.
This is done commercially via the reformation of hydrocarbons like natural gas. And, like you suggest, they'll run out.
You can also manufacture hydrogen through the electrolysis of water. This takes electricity. You get your electricity from burning fossil fuels, which like you suggest, will run out.
Unless you have a clean source of electricity to begin with, hydrogen-fueled cars aren't going to clean anything up, and they still rely on "a substance that will run out eventually."
Isn't gasoline pretty dangerous stuff? I mean, I know it's quite flammable. Does anyone remember the Happy Land fire?
Which brings my question - how do you stabilize gasoline so it's not so flammable? A car accident could spell disaster if not properly contained.
To be less sarcastic, c'mon. Cars drive around all day long with thin-walled steel 20-gallon tanks of flammable liquid hydrocarbon fuel, and they rarely rupture. Considering that to get useful vehicle ranges with hydrogen fuel, you need to have the fuel tank pressurized to several thousand psi, you're going to be making it out of rather thick steel with a helluva safety margin. Then there's the fact that hydrogen's a lot lighter than air, so if by some horrendous accident (which will involve energies more than sufficient to kill the vehicle occupants anyway) the tank does rupture, the hydrogen's going to head for the stratosphere as fast as bouyancy allows, instead of pooling on the pavement in flaming puddles.
The reactivity of hydrogen is a concern, but it's a small and easily-handled one. Where to get the hydrogen is a far larger issue.
If I remember correctly, the third phase is not enriched U235, but either natural or depleted uranium, the 238 isotope.
I explained that this bomb is not usual, and that the jacket is in fact U-235, as opposed to U-238.
U-238 *is* fissile. But the neutron has to have high energy.
Again, from my post to which you're responding: "U-238 won't sustain a chain reaction, but it'll fission merrily if you bombard it with fast neutrons."
These are produced by the fusion stage. So there is no need to use dangerous and expensive enriched uranium for the bomb casing.
The *point* is that at the time in which this bomb was designed, they did not have the hydrocodes to ensure efficient compression of the fusion stage using only the small primary trigger. So they made the casing from enriched uranium, so that they could be sure of igniting the fusion stage.
This is an old bomb, not a modern design.
While it is currently fashionable to believe that the only terrorists in the world are those of middle-eastern descent or belief,
Name me a major terrorist attack since the OKC bombing that was not carried out by Islamic extremists.
there are enough home grown idiots with grudges against the government to go out there with the bass-boat, a winch and a case or two of beer.
If two good-ol' boys with a bass boat and a winch can manage to excavate a 7,000 bomb buried under decades worth of sediment, the Terrorists Have Already Won(tm).
Yeah, you're right, that was a quick WAG based on the overall weight of the bomb, which is like 7,000 pounds. 400 pounds of high explosive, roughly a critical mass of plutonium, all the support apparatus and structure, and the jacket.
Bad estimate. In Ivy King, 60 kilograms of HEU yielded 500 kilotons, so this one's probably around 150, 200 kilograms. Something like that.