indeed, but note that c^2 is just a factor to convert between units here and is completely arbitrary (or rather, c is so high because our units are human scale)
indeed, in the most natural systems of units in this area, we set c = 1 as to simplify the equations
I'm not sure! One is just barely within human scale and one isn't. I think I could feel the impact of a mosquito on a sufficiently sensitive patch of skin. I'm not sure I could do the same with one sixth of a mosquito. Its like the difference between something I can lift (100 lb) and something I definitely cannot lift (600lb)
It's also the difference between 1lb and 6lbs also, so the analogy isn't perfect. The problem is that once you approach the limits of the average human ability, multipliers can transform something possible into something impossible.
I'm pretty sure I could feel one sixth of a mosquito hit me, because I've been pelted by much smaller gnats before!
It was on the radio here (I live on its route)- the ‚receiving’ physicist said it would be way less than what we catch anyway from daily cosmic radiation.
“Antimatter in a truck” is great headline material, but the actual advance is portable precision instrumentation.
CERN can make/store the antiprotons, but not measure them as cleanly as they want because the facility itself introduces tiny magnetic fluctuations. So this is really a story about moving the sample to a quieter lab, not moving toward sci-fi antimatter batteries... for now
It almost could be a Hollywood movie in the vein of Sorceror. Couple of grizzled CERN vets transporting a volatile load of antimatter across a post-apocalyptic wasteland while being chased by energy terrorists.
I just read Angels and Demons. My take is that it is quite gripping and entertaining, and has no other virtues. The prose is just ok, and everything built above that is increasingly nonsensical. However, I'll endorse burkaman's reply as an equally accurate and more charitable review. :)
They are very entertaining stories, that's why they're so popular. If that's what you're looking for then you'll probably like them. If you're easily annoyed by plot holes or historical/scientific inaccuracies then you might not, and if you're looking for sophisticated or artistic prose then he isn't the right author. Obviously "good writing" is subjective, but I think most people would agree that Dan Brown's writing is relatively simplistic, but that often isn't a problem when the story is good.
His books are perhaps in the same category as Nickelback albums: people love to rag on them, but if you look at the sheer number of units shifted, clearly lots of folks enjoy them.
From a layman's point of view antimatter seems like an ideal spacecraft fuel. It's as energy dense as E = mc^2 allows, and if you have infrastructure to make it, the only input you need to produce it is electricity.
Being able to transport it seems like an important piece of that puzzle.
Production and storage would need to be scaled by many orders of magnitude, but that's merely an engineering problem...right?
The confinement scheme used here is likely a Penning Trap. Such devices are limited in the amount of antimatter they can store by the Brillouin limit. The energy stored will be no more than the magnetic energy of the field of the trap, and so much less than the explosive yield of a mass of TNT (say) equal to the mass of the trap.
When I visited CERN, they mentioned that there were some large number of protons in the ring at a time, and the runs would last a significant amount of wall clock time. (Don’t remember the exact numbers, but I think it was like 10^19 atoms of H, and days of wall clock)
The upshot was, it was likely that less than a mol of hydrogen had been run through the ring.
If humanity doesn't perish in the next hundred year and masters interplanetary spaceflight, antimatter drive is the logical next step in propulsion after fusion.
Interstellar spaceflight will become (barely) feasible once spaceships can reach velocity between 0.02 to 0.1c are possible. Even assuming non-100% conversion efficiency, antimatter has enough energy density to provide this capability.
My memory is that 1g of constant acceleration grants sufficient relativity to make it to the edge of the known universe in a current human lifespan.
Now, it's true, there's some slight issues such as radiation, food storage/production, psychological effects, and any random space rocks obliterating your craft, all of which could reasonably turn out to be enough to make it not work. We also don't have a fuel source that can provide 1g of constant acceleration for 80 years for a reasonably sized space ship, though again my memory is that nothing prohibits it from a physics perspective (this is where my knowledge/understanding get prohibitively poor. I'm not sure how the math works if you stick a thousand ion drives to a spaceship that's already in space or if you just need a huge snifter of compressed hydrogen or if you can just use nuclear propulsion but I'm pretty sure that antimatter would do it, if you could bring yourself to waste the money. But maybe we don't have a plausible way to contain it so what do I know).
Maybe I'm remembering wrong, or maybe I glossed over what's currently considered a physics, rather than engineering/economic/materials science problem, but that's what it looked like last I checked.
You don't need new physics for interstellar spaceflight - 16 km/s of dV is enough. you don't even need to go that much faster to slowly spread among the stars. There are a lot of smaller bodies all the way from Sun to Alpha Centauri. As long as you hop between them within reasonable time in a few thousand years you can become a true interstellar civilization, while going at much-slower-than-light velocity (similar to Polynesian colonization of Pacific).
From a layman's point of view, I'm more interested in antimatter's potential as a weapon.
Not necessarily because I want to use it, but because I have a vague idea of what it's capable of, and what that would mean in the hands of certain groups capable of producing it.
> According to, Michael Doser, a prominent particle physicist at CERN, "one 100th of a nanogram [of antimatter] costs as much as one kilogram of gold."
Those aren't comparable costs. The cost given for antimatter is the cost of producing it from nothing. The cost given for gold is the market price of buying gold that already exists.
Consider the cost of producing one kilogram of gold from nothing.
(Consider also the cost of ownership. Gold has a higher-than-average cost of ownership; you have to provide security or it will be stolen. Antimatter's cost of ownership is far, far beyond that.)
Not to be dramatic, but wouldn't that level of destruction threaten all life on Earth? After the immediate destruction of the first county, extreme climate change would cause the same kind of problems as nuclear winter would, no?
Antimatter bombs are not a realistic technology. Aside from the unsolved technical issues - many, and fatal - no country has the GDP needed to make 1g of antimatter, which would make an explosion around 40kT.
We can't afford to blow up ourselves that way.
There are plenty of other ways we can afford, so antimatter isn't top of anyone's worries.
> If you're ok with the looming threat of total annihilation.
Don't you have that problem with any energy-dense fuel? It's just that it doesn get more dense than that, so you can be very space and weight efficient.
It's like everybody saying that a hydrogen car is a rolling bomb because of the energy stored in the hydrogen. Well, sure, but gasonline has just as much energy stored. Which is the whole point of fuel. To store energy. It's not like you are bringing 100x as much energy with you just because it's hydrogen. So that doesn't make an ICE car any less of a bomb...
The difference is that antimatter annihilates with any normal matter that it comes into contact with. This means you can't just put it in a tank, the way you can with hydrogen. You can't e.g. combine it with some metal to make a metal hydride to make it safer to store, the way you can with hydrogen.
At an absolute minimum, you need extremely strong magnetic confinement and an extremely hard vacuum. And even then, you're going to get collisions with stray atoms and annihilation events which release gamma rays and other radiation products - although shielding is probably the least of your worries in this scenario.
A typical research lab at a university or large corporation can't make a vacuum strong enough to store even tiny quantities of antimatter for more than a few minutes, and they can't produce the magnetic confinement strength required to store macro quantities of it, either.
So the question with an antimatter-powered car is not if it's going to destroy the surrounding region and bathe it in hard radiation, but how many milliseconds (or less) it will take before that inevitably happens.
But probably luckily for us, this is all moot, because we have no way of producing enough antimatter for this to be an issue. If all the antimatter that's ever been created by humans annihilated simultaneously, only scientists monitoring their instruments closely enough would notice, because it's such a microscopic amount.
Edit: for perspective, you'd need about 7 billion times the 92 antiprotons transported in the truck in the story to produce the energy produced by a single grain of gunpowder.
Liquid gasoline does not spontaneously explode like an action movie. You can put a match in the fuel tank and (presuming infinite oxygen availability) it'd just start a small fire. Heck, may even just give a little puff and then put out the match.
Antimatter in any sufficient fuel quantity, the moment it breaks confinement, will completely annihilate and release ALL it's energy in a single moment, setting off a chain reaction to the remaining antimatter. It's like sitting on an armed nuclear bomb, where you rely on electrified, highly sophisticated containment equipment never failing a single time for months to years... In a radiation-heavy environment known for causing sophisticated electronics to have errors.
And, yes, hydrogen cars were looked at critically because of the perception they can Hindenburg (I'm unsure if it's true or not). Which is a good example because you don't particularly see any hydrogen blimps anymore - we made them illegal because they're dangerous.
Any compressed gas fuel is inherently dangerous. There's a video of a CNG-fueled bus falling off a lift and sending a fireball through the maintenance facility.
Batteries have some of these same risks: they store a lot of energy and it can be released very quickly under the wrong circumstances.
Average human threat perceptions simply aren't useful here. People will also make wild assumptions about what kind of catastrophic thing could happen in aviation and then happily enter their car to drive somewhere without a thought in the world. In fact noone thought about designing gasoline fuel tanks in a safe way before we had cars. Not even really until people started burning. If we're already thinking about transporting antimatter safely today, this kind of technology will probably have an even better track record than planes.
Antimatter reactions are about a million times more powerful than conventional combustion. They surpass even nuclear explosions in energy release. That means even a small mishap becomes a large mishap.
Nuclear energy is limited to a little less than 1% of the energy release possible with antimatter, per mass.
The practical limit for nuclear energy is about 5 to 10 times less than that, because the theoretical limit corresponds to the transmutation of hydrogen into iron, coupled with the capture of the entire energy, which will not be achievable any time soon.
But there is an essential difference between nuclear energy and antimatter energy. Nuclear energy is stored in our environment and you just have to exploit it. Antimatter energy is a form of energy storage, so you need some other form of energy to make antimatter. The energy efficiency of making antimatter is many orders of magnitude worse than the factor of less than 100 that exists between nuclear energy and antimatter energy and the mass of the confinement device needed for storing antimatter is also orders of magnitude greater than the mass of the stored antimatter.
For now, there is absolutely no hope of ever using antimatter in practice for storing energy. Such a thing could be enabled only if some technologies that we cannot imagine would be invented.
Despite the great technological progress of the last couple of centuries, it is hard to say that there have been many inventions that have never been imagined before. After all, already 3 millennia ago the god Hephaestus did his metal smith work with the help of intelligent artificial robots.
Not familiar with the subject so genuine question. HOW would antimatter be used as fuel? There is energy released in matter antimatter annihilation, but where would the force to move a spacecraft come from?
> Various antiproton-powered rocket systems have been proposed. All of which rely on the particles released to supply direct thrust or to heat a working fluid by interparticle collisions or by heating a solid core first [14]. There is also the possibility to use the heated working fluid to generate electricity for electric propulsion systems [14].
> Following Fig. 9, beam core and plasma core configurations can produce direct thrust by directing the charged particles produced into an exhaust beam using a magnetic nozzle. Gas core systems use the energy released from the reaction to heat a gas that is exhausted for thrust. Finally, solid core configuration heats a metal core like Tungsten that acts as a heat exchanger to a propellant that is then exhausted from a regular nozzle.
my absolutely-non-expert guess is that it would work much like any other fuel? Combine with matter, get a lot of head out of it and use that in the best way we know.
I am curious about how much energy needs to be expanded to contain the anti-matter. Say it the matter/anti-matter is to be used for propulsion/energy generation can we reach a threshold were we are actually energy positive
How could we make enough antimatter to do something useful? Would we need to go hang out near the sun or deorbit Jupiter's moons with superconducting coils to get enough energy?
It would develop into "regions" of space that are entirely matter and others that are entirely antimatter. The boundaries between them would glow as stray particles drift between the regions and are annihilated by contact with the opposing particles.
The fact that we don't see these glowing boundaries in space is evidence that there are not antimatter regions and that the visible universe is almost entirely composed of matter.
It would depend on how it's distributed. If it's very homogeneous, totally anihilated. If there are galaxies of matter and galaxies of antimatter, more or less like us with a bit more background radiation.
Mass in the universe appears to be (very) roughly uniformly distributed, so even if there are large bodies of antimatter far away in the universe there would have to be a transition boundary somewhere between here and there where the universe goes from being mostly matter to being mostly antimatter. The universe is big and stuff would sometimes cross this boundary and get annihilated, and if this happened it would be the brightest thing in the sky, briefly outshining entire galaxies. We’ve been watching the sky for a while now and have never observed a bright visual event with the spectral signature of a matter/antimatter annihilation, so we assume there is not such a transition boundary, and by extension that the universe is made up of mostly matter out to the edge of the observable universe.
Great explanation. One thing to add: annihilation happens with a very specific energy. Even if it was very far away and redshifted and dim, a "bubble" with a very uniform color (photon energy) would be plainly visible.
It talks about symmetries, but has a nice story about this exact hypothetical scenario. (Someone else already replied why this probably isn't possible in our observable universe, but the episode is cool so I thought I'd share)
Unless we'd be fighting literal alines in space, and need a weapon for them, I think this would be many many many orders of magnitude too expensive / tricky for earth use. We have plenty of non sci-fi big boom sticks already as it is...
You (briefly) have an antiproton in your possession around once a day, assuming you get an average amount of sunlight. Some days, you might even have two!
well either way they're in opposite helicity states...
but yes, Majorana neutrinos nothwithanding, there are plenty of transported positrons detected by e.g. PAMELA and plenty of antimuons that go long distances.
Every time I read one of these, I am amazed by how much stuff superconductivity allows, and how limited we are because it needs ultra low temperatures.
Imagine the poor post-doc in the back of the truck, no seatbelt, watching and noting anything going on, while the driver is doing donuts in a parking lot to really stress-test the magnetic containment.
Yes, only anti-truckers can haul anti-matter since normal CDLs only let you transport ordinary matter. You have to be very careful not to let the anti-trucker go to a ordinary truck stop because things really go down if they run into a ordinary trucker.
Imagine your own, household matter/antimatter reaction chamber. I can hardly wait for antimatter to be transported through pipes underground along side water mains, natural gas pipes, and sewer connections.