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NASA to Research Antimatter Rocket
Fraser Cain writes "One of the dozen technologies selected by NASA's Institute for Advanced Concepts (NIAC) this year is Positronics Research's ideas for an antimatter rocket engine. Instead of 3100 kg of propellant on board Cassini, the spacecraft could get by with just 310 micrograms of electrons and positrons. Of course, making the antimatter can be expensive."
310 micrograms of antimatter may not sound like much, but the laboratories that produce the largest amounts of antimatter (CERN, Fermilab, KEK, SLAC, ...) only make about 10 nanograms per year!
According to the Wikipedia producing antimatter is quite expensive. They mention something of $25 billion per gram.
That's around $7'750'000 for these 310 micrograms...
In terms of destructive power, it's actually a lot less dangerous than you'd think: http://en.wikipedia.org/wiki/Antimatter_weapon
Speaking as someone who uses antimatter every day, I have to point out that at least now, antimatter is very difficult to make. We expend 100,000 protons (ones that have been accelerated to very high speeds) to make one anti-proton. They get "stored" in a large accelrator complex underground (much bigger and bulkier than a spacecraft). After about half a day of this, we produce about a hundred thousandth of a microgram of antiprotons (which we then smash the hell out of).
Hold your horses...
You dont seem to know your physics THAT well..
First: 5g antimatter wont destroy the earth. In fact, it would be more like a medium sized hydrogen bomb-> it doesnt even make dent in any bigger mountain.
Second: Antimatter is a storage only device. Every bit of energy created by a detonation has to be produced by other means, first (in fact, 1000 times or more, because of abysmal efficiencies). So to even have the _possibility_ of creating planet_buster or armageddon-device amount of antimatter, you need energy sources that could do it anyway...
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
Here
Whenever I need to know something, I just check Wikipedia.
Well, captain obvious...
Without electromagnetism is would be impossible, but even with it its really damn hard...
Dont forget: if you wanna store large amounts of anitmatter, you can forget positon only storage simply because of colomb forces... 300ug positrons or antiprotons would ruin any attempts to trap them...
So you need anti-hydrogen atoms. Doable, but still tricky. Because now, you have to use higher order fields to trap. Something like a penning-trap. Of course now, you can get spin-flips that will result in the flipping atom to be accelerated to the walls... causing gamma photons... now those can travel through the contained material and wreck all kinds of havoc, ect...
Its not as easy as its sounds, ESPECIALLY if its should be small enough to be packed on a rocket... (storing antimatter in a large storage ring is a whole lot easier)
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
The posters here missed the mark.
Making positrons is actually much easier than making antiprotons. Pair production on photons produced in accelerators should give efficiencies of 5 to 10% -- and the positrons are much easier to cool.
The big problem with positrons is storing them. Unless these people have a major new idea to get around the Brillouin limit on Penning Traps, the energy stored per mass of equipment will be too small to be interesting (even worse than the energy/mass of chemical propellants.)
Very true. Nuclei contain far greater amounts of energy than any exothermic chemical reaction. But if you ask me, all large-scale power generation has crawled forward because it all still depends on massive reheat cycles and steam turbines. The only way to make a better power conversion system is through massive amounts of research into materials capable of more efficient energy transfer such as those found in the newer generations of RTG's and solar panels as a quick example (obviously not large scale generation but big projects stem from small projects in engineering). Much of this research couldn't be done 30-40 years ago since it takes massive amounts of computing power to design and model the systems under all sorts of conditions. Also the leaps and bounds in terms of MEMS technology, miniaturization of transistors, plastics and fiber, etc has led to greater knowledge of nuclear processes that will start to lead towards better power generation. So I don't think it's a lack of research into nuclear power generation at all, but rather a lack of prerequisite knowledge to advance such a dependent technology such as this.
In 1939, the US department of the interior predicted that oil would last only 13 more years. In 1951, it made the same projection: oil had only 13 more years. As Professor Frank Notestein of Princeton said in his later years: "We've been running out of oil ever since I was a boy." Regular gasoline costs the same in real terms as it did in 1950. In the 1960s overpopulation was going to cause massive worldwide famine around 1980. A decade later we were being told the world would be out of oil by the 1990s.
I have this sinking feeling that in 20 years, someone will post on /. that "the crude oil reserves will be exhausted in about 20-30 years."
You can't add pianos and telephones.
what are the odds of that?
I wouldn't worry too much, because it seems such a bomb would cost around a quadrillion dollars. (I'm assuming Moore's Law doesn't apply here.)
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Terrorists can't threaten a country's freedom and democracy. Only lawmakers and voters can do that.
The reactors used on submarines are a very special case though. Firstly, they use highly enriched which isn't good for public consumption because runaway reactors with HEU would be very, very bad. Second, since a submarine has the requirement that is has to go from no power to full power in seconds, it has a very, very, very large, active neutron source (on the order of a few curies if memory serves correctly, but it's been quite a while since I worked on anything nuclear that ran on earth ;-) ). The k-effective of a nuclear sub that isn't "on" is usually at about .90~.95. Which means that all it needs is to remove the control rods ever so slightly to start producing power. Also the cooling mechanism of nuclear subs uses seawater as a secondary coolant since it's so abundant. The primary coolant doesn't leave the core obvious, but it's the secondary which directs where that heat will go. So for a small scale reactor, this isn't the way to go, but more towards an RTG, which is what's used in satellites. They aren't exactly small, but they run on the Seebeck effect (reverse of the peltier effect for you computer people). The fuel in an RTG doesn't create the heat/energy by fissioning, but rather by natural alpha decay (heavy,unstable isotope releasing ionized helium atom). The helium atom has a certain amount of energy, usually in the 5+MeV range since the fuel is usually a plutonium isotope. So with that amount of energy being released at a near-constant amount for 25+ years, the benefit would be great; however, shielding and non-proliferation issues persist and render using this as a mainstream, use-at-home reactor as impossible. But one of the things beind worked on by the IAEA along with a few of the US nat'l labs and other is a large RTG that can be safely deployed to areas to use as a portable power plant. It'd be cool, but huge, and expensive until better materials are worked out for shielding.
nope - you're using grams, not kg, making you 1000x out. its 5*c^2, not 5000*c^2
As someone else on this thread has pointed out, you actually have do double that, because 5kg of normal matter is destroyed as well.
But from the link that someone else provided (http://en.wikipedia.org/wiki/Antimatter_weapon) 60% of the yeild of an antimatter explosion escapes as neutrinos, and most of the rest as gamma rays so its not nearly as dangerous (or practical, if desctruction is your goal...) as a regular H-Bomb.
Nope, the gram isn't correct unit in this case; the kilogram is. grams*(m/s)^2 equals millijoules.
& q=5000+g+*+c%5E2
If you don't believe, ask google: http://www.google.com/search?client=safari&rls=en
[ Antti Rasinen ]
There are a couple of ways it could be useful:
1. Nuclear Steam Ships can have a relatively high Isp (compared to chemical rockets) while using a fuel that's easily obtainable from a nearby body such as the moon.
2. Magnetoplasmadymanic thrusters are based on MHD theory, and have some of the HIGHEST Isp of any rocket engine. In addition, they have a relatively high thrust to weight ratio as well. (Very rare in engines with such a high Isp.)
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I could be wrong about this, but I heard there was talk of Sun power actually existing in space, outside of Earth!
You have the solar power, but you're lacking the Earth sized solar collector. Obtaining 1.3kw/m^2 (the amount that hits the Earth) isn't very much energy when your panels are only a few meters square and have an efficiency rating of <20%.
Using the sun for direct propulsion (solar sails) is a viable concept, but the materials tech is still trying to produce high quality sails.
Javascript + Nintendo DSi = DSiCade
Look, physicists have this notion of a vacuum state. It's the lowest energy state a system can occupy. You can't extract energy from a vacuum state because then it would be left in a lower state contradicting the fact that it's a vacuum state. So it doesn't matter if a vacuum state has cocktail sipping blue-tongued skinks materializing out of nothing. You can't extract energy from it.
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
An antimatter rocket has to lift the weight of the unit built to contain the anti-matter. Since at present that unit would weigh far more than the weight of the fuel saved the anti-matter unit would have to be more powerful than a chemical rocket.
Assuming antiatoms exhibit the same properties at normal atoms (ie carbon is diamagnetic, therefore anticarbon is diamagnetic), you could in principle form an antimatter solid or liquid made of antiatoms that are diamagnetic and suspend it in a magnetic field (Lithium and Beryllium have susceptibilities of ~6 X 10^-5).
On the other hand, you'll never get much acceleration this way: Each tesla of magnetic field will generate about 3-5 M/S^2 of repulsion in those materials, which is how much acceleration you get before they bottom out. That and it compounds the massive energy inefficency of synthesizing antimatter with that of fusion of the resulting antihydrogen...
I am working a 12-hour owl shift overseeing the antiproton source at Fermilab. And reading Slashdot.
At this very moment, our pbar production efficiency is roughly 16E-6pbars/p, about average these days. That means that for every million protons we slam into the target, we capture and store 16 whole antiprotons. We're stacking at a rate of 14E10pbars per hour, again about average for us.
Having had almost five years of experience running particle accelerators and creating antimatter, I find the ideas in TFA to be kind of ridiculous. We are very far from being able to create antimatter efficiently enough to do anything other than collider physics, and even that is old hat. No one cares about the pbars anymore; neutrinos are where it's at these days.
Having worked rotating shifts for almost five years, I am tempted to apply for a job with the outfit in TFA, get out of shiftwork, and get my hands on some of NASA's grant money.
Cheers!
Ow, ow, the pain. The grandparent, and the parent, and you, everone in this thread is butchering the science.
the way I got it is that in our universe there is a center (with galaxies and stuff) that is not completely vacuum and outside of that there is (still, perhaps) vacuum, and just like air is sucked into a room with a vacuum in it our universe is sucked apart
No, our universe has no center and no outside. It's a very common misconception, but the big bang was *not* an explosion like a handgrenade.
The universe is more like the skin of a ballon, and galaxies are dots on the skin of that balloon. The big bang and the expansion of the universe is more like that balloon being inflated. Except there is no "inside" or "outside" of the ballooon. The universe is *just* the skin, and that skin stretching. It's not stretching into anything or into anywhere, just stretching into the future.
The closest thing you can say to being the "center" of the universe is the point in the past, the big bang. Every point in the universe right now is equally close... and equally far... from the center.
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You made a minor mistake in your E=mc^2 math. The mass you use should take both the antimatter and the matter into account because any given matter-antimatter reaction involves the conversion of matter and antimatter into pure energy. This results in 10 kg being converted into energy, or about 10^18 Joules or 125 megatons.
And in case you were wondering if the other poster that claimed bad math was right or not, he's wrong. The correct units are J=kg*(m/s)^2 like parent used.
ZPE is what they think is forcing the galaxies apart.
No, it isn't. Zero point energy is inherently useless as a power source. It is an equal and isotropic pressure across all space. It would be just the same as trying to use ambient temperature as an energy source. Just can't happen by thermodynamics.
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