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Aug 07 2011

Anti-matter! In space!

Science fiction dreams may come true: a small, thin band of stable anti-matter has been discovered near Earth. It was predicted theoretically, but now emissions from the annihilation of these particles has been observed.

The existence of a significant flux of antiprotons confined to Earth’s magnetosphere has been considered in several theoretical works. These antiparticles are produced in nuclear interactions of energetic cosmic rays with the terrestrial atmosphere and accumulate in the geomagnetic field at altitudes of several hundred kilometers. A contribution from the decay of albedo antineutrons has been hypothesized in analogy to proton production by neutron decay, which constitutes the main source of trapped protons at energies above some tens of MeV. This Letter reports the discovery of an antiproton radiation belt around the Earth. The trapped antiproton energy spectrum in the South Atlantic Anomaly (SAA) region has been measured by the PAMELA experiment for the kinetic energy range 60-750 MeV. A measurement of the atmospheric sub-cutoff antiproton spectrum outside the radiation belts is also reported. PAMELA data show that the magnetospheric antiproton flux in the SAA exceeds the cosmic-ray antiproton flux by three orders of magnitude at the present solar minimum, and exceeds the sub-cutoff antiproton flux outside radiation belts by four orders of magnitude, constituting the most abundant source of antiprotons near the Earth.

I had to laugh my cynical, evil laugh at the BBC report on this discovery, though.

The team says a small number of antiprotons lie between the Van Allen belts of trapped “normal” matter.

The researchers say there may be enough to implement a scheme using antimatter to fuel future spacecraft.

Bwahahahahaha! Space travel? Foolish, optimistic journalists. You know the first use of these things, once the means to harvest and maintain them is found, will be anti-matter bombs.

(Also on Sb)

41 comments

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  1. 1
    Dhorvath, OM

    Well, that is pretty nifty. It’s always nice to see science predicting something and then finding it. It’s the ultimate compliment as I see it.

  2. 2
    The Very Reverend Battleaxe of Knowledge

    You know the first use of these things, once the means to harvest and maintain them is found, will be anti-matter bombs.

    The two go together. It would take forever to collect enough to use directly, but only about a microgram apiece to catalyze pure-fusion (i.e. no fallout) bombs to build an Orion.

  3. 3
    Timinane

    I know we’ll blow ourselves up before we make a ship (Damn dirty apes) though I assume the fights over the name of the ship will be the final efforts of humanity as the remaining nerds try and decide from the following options.

    a) Enterprise
    b) Deathstar
    c) Macross
    d) Discovery – 1
    e) Vatican (Missionary to the stars, operated by HAL9000)

  4. 4
    Glen Davidson

    Bomb-wise, about all that would be gained with antimatter would be miniaturization. Good for terrorists, mainly, but they probably wouldn’t be able to handle or harvest it.

    For spaceships, well, handling would still be an issue–and dilithium crystals have a tendency to overheat and to otherwise fail. More seriously, you’d probably need a near-perfect mirror for a really good antimatter drive, and they seem doubtful. I can’t really see why anyone would use antimatter bombs to power project Orion–explosions aren’t a good way to drive a spaceship.

    Glen Davidson

  5. 5
    MadScientist

    I was laughing at the claim of having enough to fuel spacecraft. Having 4 magnitudes more than produced by cosmic rays isn’t going to help with powering anything because although it’s an awful lot in bulk, it’s spread way too damn thin to be put to use. On top of that – how *do* we use antiprotons to create energy? It’s not as if we can collect them somehow and release them in a controlled fashion while magically creating more energy than we spend, otherwise we’d have Antimatter Reactor Power Plants ™ running.

  6. 6
    The Very Reverend Battleaxe of Knowledge

    I can’t really see why anyone would use antimatter bombs to power project Orion–explosions aren’t a good way to drive a spaceship.

    It may be the only way to drive a spaceship with the kind of specific impulse needed. Imagine a pure matter/antimatter drive. To produce even the (vacuum) thrust of one Space Shuttle Main Engine would take over 600 Terawatts of power. Even if the engine was 99% efficient (which of course it wouldn’t be), that’s 6 Terawatts of waste heat to get rid of.

    So very low-thrust applications for use in space may be possible, but to get into orbit in the first place, you’re going to have to use that energy to heat up some reaction mass and shoot it out the exhaust. If you’re going to be building an engine with much higher specific impulse than chemical rockets (and what’s the point otherwise?) You’re going to have that much more waste heat, and that much less intermediate fluid to carry it away.

    The only solution may be to have all the energy expended externally. Cooling the pusher plate of an Orion would be a tough enough task—trying to get rid of all that waste heat if it were produced internally may be impossible.

  7. 7
    Franzl Lang

    Completely off-topic: I notice that each time I open Pharyngula’s site on Freethoughtblogs in my browser, I have to press the refresh button to get the new articles that were published since the last time I visited the site. This didn’t happen at Scienceblogs.

    Did anyone understand my problem at all? Does anyone have the same issue?

  8. 8
    The Very Reverend Battleaxe of Knowledge

    I should point out that the United States uses an average 24/7/365 of about 2.5 Terawatts of power—and that’s all forms of energy consumption put together.

  9. 9
    The Very Reverend Battleaxe of Knowledge

    @ Franzl Lang:

    It’s taking the last page you viewed out of your browser cache. My observation was the opposite—SciBlogs was one of the few sites I visited that forced a complete refresh every time I went there. So—yeah, I’m worthless to you. Anybody know how to prevent your browser from cache-refreshing without disabling it?

  10. 10
    The Very Reverend Battleaxe of Knowledge

    Unless the old trick of holding down the “shift” key when you hit the bookmark would work—or is that OS X-only?

  11. 11
    joed

    Glen Davidson @9:52
    Actually Glen, the terrorists handle nuclear bombs very well, just ask Nagasaki/Hiroshima. The terrorists you speak of are probably the freedom fighters from Afghanistan etc.
    The real terrorists are U S and Euro murderers and hate-filled thugs.
    No offence meant Glen. It is important to keep our terrorists clear.

  12. 12
    frankensteinmonster

    explosions aren’t a good way to drive a spaceship.

    [citation needed]

  13. 13
    frankensteinmonster

    Bwahahahahaha! Space travel? Foolish, optimistic journalists. You know the first use of these things, once the means to harvest and maintain them is found, will be anti-matter bombs.

    so what. antimatter bombs would be not more dangerous than nukes are, because that antimatter is far more expensive and difficult to get, than the equivalent amount of plutonium is.

  14. 14
    Glen Davidson

    So very low-thrust applications for use in space may be possible, but to get into orbit in the first place, you’re going to have to use that energy to heat up some reaction mass and shoot it out the exhaust. If you’re going to be building an engine with much higher specific impulse than chemical rockets (and what’s the point otherwise?) You’re going to have that much more waste heat, and that much less intermediate fluid to carry it away.

    You can’t explode antimatter bombs to get into space. They may be low-fallout, but what they’d be putting out is hard gamma rays and neutrinos. Neutrinos aren’t a problem, or any use, while gamma rays, well, they’re extremely deadly. And since a major problem with Orion in space was always radiation, I can’t see what shifting to even more gamma rays would accomplish in the first place.

    Orion probably has one use worth considering–as a means of diverting an earth-threatening asteroid or comet. Conventional nukes would likely do well enough.

    Glen Davidson

  15. 15
    Phillip IV

    Spaceships? Bombs? Laughable! That would be a total waste of the vast potential of his discovery. No, what we should do is a remake of the 1957 movie “The Giant Claw” – but this time with a real ANTI-MATTER SPACE BUZZARD!

  16. 16
    The Very Reverend Battleaxe of Knowledge

    You can’t explode antimatter bombs to get into space. They may be low-fallout, but what they’d be putting out is hard gamma rays and neutrinos.

    Did you read the article? You’re not “exploding antimatter bombs”—you’re using a very small amount of antimatter to ignite a pure-fusion bomb with no fission primary (and needless to say, no depleted-uranium pusher). They only talk about lithium deuteride, but maybe you could use boron-11/hydrogen for no radiation at all.

  17. 17
    Glen Davidson

    small amount of antimatter to ignite a pure-fusion bomb with no fission primary (and needless to say, no depleted-uranium pusher). They only talk about lithium deuteride, but maybe you could use boron-11/hydrogen for no radiation at all.

    No radioactive waste, that is. You can’t have either fission or fusion without producing at least x-rays, usually gamma rays. There might be ways of shielding and expelling some sort of fluid, but that always involves using more matter, and lofting more weight.

    Lithium deuteride explosions would expel considerable tritium, which is quite a radio-toxic substance. As far as I know, deuterium-tritium (and variants) is all that has given us good explosions, and even the secondary of most fusion devices includes highly enriched uranium to make it more compact and efficient.

    The one good thing about antimatter triggering is that fusion bombs might be made much smaller than they can now be made. If these were then exploded in a kind of huge chamber in space, it might make a useful rocket–although obviously a very expensive one.

    Glen Davidson

  18. 18
    Bill Dauphin, avec fromage

    So very low-thrust applications for use in space may be possible, but to get into orbit in the first place,…

    …you use chemical rockets, which are perfectly adequate to the task. Earth-to-orbit transportation will eventually get cheaper and easier due to the development of better mission architectures and clever combined-cycle propulsion systems, but it will always, I suspect, be based on burning fuel and oxidizer. Maybe we’ll see other sorts of kinetic launch (railguns, lasers, etc.) for some applications, but I cannot envision any reasonable scenario in which antimatter or nuclear propulsion is used to take off from the surface.

    Which, quite obviously, is no reason not to study those systems for in-space propulsion.

  19. 19
    andyo

    Anybody know how to prevent your browser from cache-refreshing without disabling it?

    Usually CTRL+F5 is a brand new refresh (as opposed to a regular F5 refresh) on browsers. I know Firefox does it, and I think IE too. But what I do to avoid this is set Firefox to only delete cache every time it closes.

  20. 20
    Marcus Ranum

    I wonder if somehow naturally-occurring antimatter could be harvested and used to bootstrap self-sustaining fusion reactors? Hey! Free energy!

  21. 21
    Brett

    How would you go about harvesting the band of anti-protons?

    Storing them would be a beast, too, even with the ability to use magnetism to confine them.

  22. 22
    Santiago

    I think people seriously underestimate the difficulties inherent in safely containing anti-matter for long periods of time. It is actually *extremely* difficult to bottle anti-matter in useful quantities for any length of time. All currently proposed systems also suffer from extreme instability: if the containment starts to fail the energy released as the first few particles annihilate will cause the containment failure to worsen allowing more particles to annihilate which emits more energy and soon enough you have a chain reaction and a very big BOOM.

    Not saying that it won’t be useful for use in space (since things in space can generally go BOOM without much fear of collateral damage) but whoever wants to use anti-matter for bombs is absolutely bonkers. As someone said above the only advantage would be further miniaturisation of nukes but they’re already pretty small and delivery methods are pretty efficient nowadays, there’s really no big advantage for a major military power to further shrink their warheads.

    On the other hand anti-matter warheads pose *tremendous* safety risks. Modern nukes are inherently safe in that they could literally be exploded but if the safeties have not been removed they will NOT, themselves, explode. This is important because the sheer number of nukes lying around makes it inevitable that one will eventually get knocked around hard, maybe a plane will crash while armed with one, and you want to make sure your nuke doesn’t accidentally go off. Such safeties are almost impossible to implement with anti-matter bombs. And it is likely that the safer you made the anti-matter bombs the bulkier they’d have to be, thus negating their vaunted advantage. All in all, a terrible idea. You can rest assured PZ that anti-matter applications will remain an essentially civilian affair.

  23. 23
    The Very Reverend Battleaxe of Knowledge

    …you use chemical rockets, which are perfectly adequate to the task. Earth-to-orbit transportation will eventually get cheaper and easier due to the development of better mission architectures and clever combined-cycle propulsion systems, but it will always, I suspect, be based on burning fuel and oxidizer.

    It would be possible to reduce the cost substantially if we’d go back and build something like the Chrysler SERV, like we should have done in the first place. Reinventing the wheel, like SpaceX is doing, won’t cut the program.

  24. 24
    Equilibrium

    They say the expected kinetic energy range is somewhere between 60-750 MeV. But according to Wikipedia 1 TeV (1000 MeV) is about the kinetic energy of a flying mosquito. I guess I am missing something here. Can someone please enlighten me :D

  25. 25
    Glen Davidson

    Maybe we’ll see other sorts of kinetic launch (railguns, lasers, etc.) for some applications, but I cannot envision any reasonable scenario in which antimatter or nuclear propulsion is used to take off from the surface.

    Or hypersonic air-burning. It’s no magic bullet, but under certain assumptions it could roughly double payload weight per total weight.

    Fortunately for the perpetually-underfunded space program, the military will likely develop hypersonics for making missiles, so we’ll get to find out if hypersonics will work for launching into space.

    If it’s just for the benefit of science, of course, there’s little chance of decent funding. Otherwise we’d have decent nuclear thermal rockets by now (for pure space, of course).

    Glen Davidson

  26. 26
    The Very Reverend Battleaxe of Knowledge

    This is important because the sheer number of nukes lying around makes it inevitable that one will eventually get knocked around hard, maybe a plane will crash while armed with one, and you want to make sure your nuke doesn’t accidentally go off.

    It’s happened more than once. A B-47 lost a bomb over South Carolina in 1958, and some of the high explosive went off. And of course, there’s the Titan II that exploded in its silo, throwing its warhead some distance away—again, at least one facet of the high explosive went off.

    The real concern is that after the transition to the air lens-type primary, with only two detonators, what if one of them accidentally went off? The computers at the time weren’t up to modeling the explosion well enough to give assurance that one out of two detonators going off wouldn’t compress the pit enough to produce a nuclear explosion of sorts.

    That was the reason for that frenzy of testing just before the test-ban treaty went into effect. You see all these tests with very small yields, and wonder: “How are they managing to design so many duds in 1963?” Actually, any measurable yield at all represented a failure—they wanted a safe primary that wouldn’t produce a nuclear explosion accidentally.

    It’s pretty clear that before that, planes were flying around carrying bombs that would have exploded at reduced yield in the event of an accident.

  27. 27
    Bill Dauphin, avec fromage

    Rev. Battleaxe:

    It would be possible to reduce the cost substantially if we’d go back and build something like the Chrysler SERV, like we should have done in the first place.

    That approach falls under my comment about better mission architectures and(/or) clever combined-cycle approaches. So does the hypersonic airbreathers Glen Davidson mentioned, and even farther-out ideas like the http://en.wikipedia.org/wiki/Orbital_airship>airship-to-orbit system proposed by John Powell and JP Aerospace. The point is, they’re all based on in-hand technologies that, at their base, involve chemical combustion.

    BTW, the history of space travel is littered with great ideas like SERV, Gary Hudson’s Phoenix (not to mention Roton!), etc., that never got built, and while that’s in part because of the exigencies of markets and politics, it’s also true that many (most? all?) of these concepts failed to “close” once the engineering got past the back-of-the-envelope stage. SSTO isn’t as easy as it looks (and NASA, et al. aren’t really as stupid as they look).

    Reinventing the wheel, like SpaceX is doing, won’t cut the program.

    IMHO, SpaceX isn’t so much reinventing the wheel as refining it, and they absolutely are part of the solution/future. Between SpaceX and Bigelow Aerospace, there’s a real potential to create an ongoing private market for human spaceflight (which is to say, not merely “space tourism” for rich playboys, but also access to orbital spaceflight for private companies, scientific and educational institutions, and non-spacefaring governments). This market may, in turn, drive the development of systems that can truly provide airline-like access to Earth orbit.

    In any case, though, nothing more than what SpaceX has on the drawing board (if not already flown) is required to support the on-orbit construction, provisioning, and launch of a crewed deep-space mission.

  28. 28
    outaworkee, back at work for now.

    What about the ship name of St. Michael. Niven and Pournelle would be proud.

  29. 29
    amphiox

    Reinventing the wheel, like SpaceX is doing, won’t cut the program.

    That really is not a fair description of what SpaceX is doing at all.

    What they’re doing is improving that wheel, taking the already established engineering and modernizing it in every conceivable aspect of materials, construction, control, and design.

    You have the consider the very real possibility that it looks superficially like retreading what NASA did in the 50′s and 60′s because that is in fact the best way into orbit with current technical capability and that the entire shuttle program, from conception onwards, was a massive mistake, a wrong turn into a fruitless engineering cul-de-sac.

  30. 30
    Skepgineer

    Most generous possible back of the envelope calculation for how much of these get produced in/near earth in a year:

    minimum cosmic ray energy necessary to spawn an antiproton: 1 GeV
    Average number of antiprotons from such an event: let’s say 1
    flux of cosmic rays that energy or greater: ~2000 per m^2 per steradian per second from guesstimate integral of that graph.

    (mol/6.022*10^23)(31*10^6 s/year)*(4*pi*radius of earth^2)*(12*pi*sr)*2000/(s*sr*m^2)

    2023mol/yr of antiprotons

    Now suppose we capture ALL the antiprotons and use them in a weapon.

    A megaton is 4.184*10^15 joules.
    2023mol*2*(1.01g/mol)*c^2 = 3.67*10^17 joules
    Ignoring the portion of that that gets wasted on neutrinos, we’ve got about 87 megatons.

    Now adjust the fraction we actually capture down to a realistic number and you end up with jack shit.

  31. 31
    Brian H

    They say the expected kinetic energy range is somewhere between 60-750 MeV. But according to Wikipedia 1 TeV (1000 MeV) is about the kinetic energy of a flying mosquito. I guess I am missing something here. Can someone please enlighten me :D

    Kinetic energy scales linearly with mass at fixed velocity. Your average mosquito is 21 orders of magnitude more massive (O(1mg)) than a proton (10^-27 kg).

    A proton at 100 MeV is moving at ~.4c, whereas a mosquito at 1 TeV is moving at (10^-9)c

  32. 32
    frankensteinmonster

    that is in fact the best way into orbit with current technical capability

    yeah right. because our decadent civilization has forgotten how to build both nukes, nuclear reactors, and big steel structures, decades ago ;)

    So both this one, this one, and this one are far beyond our current tech level… ;)

  33. 33
    Bill Dauphin, avec fromage

    frankensteinmonster:

    Unless I miss my guess, nobody is saying we don’t know how to do nuclear bombs, or nuclear reactors, or big steel structures; we are (or at least, I am) saying that nuclear explosions, or nuclear spew, is a terrible way to lift off from the surface of our one-and-(so far)only planet, compared to the perfectly well understood technology of rockets. We really need those exotic, high-energy solutions to do interplanetary (never mind interstellar) travel; to get to orbit, not so much.

    In point of fact, though, Orion, NTR, etc., really are pretty far beyond our current level of well understood, operations-ready technology. It’s one thing to know how to blow up bombs; turning them into a usable, manageable, affordable rocket hasn’t even come close to being demonstrated. And, IMHO, never will be for Earth-to-orbit applications: The political, social, and environmental risks are too high, and the payoffs relative to chemical-based orbital propulsion are too miniscule.

  34. 34
    frankensteinmonster

    The political, social, and environmental risks are too high, and the payoffs relative to chemical-based orbital propulsion are too miniscule.

    You have to be kidding me. Orders of magnitude more payload at the same cost is ‘miniscule’ ? If our species just could escape the self-imposed straitjacket of radiation phobia…

  35. 35
    Bill Dauphin, avec fromage

    frankensteinmonster:

    The political, social, and environmental risks are too high, and the payoffs relative to chemical-based orbital propulsion are too miniscule.

    You have to be kidding me. Orders of magnitude more payload at the same cost is ‘miniscule’ ?

    Where are these orders of magnitude of which you speak? Have they been given any real-world engineering demonstration, or do the exist only on a damp cocktail napkin in your jacket pocket?

    But let’s stipulate them, shall we? My point is that we don’t need orders of magnitude better performance in the Earth-to-orbit arena: What we need, instead, is straightforward, operationally simple, sustainable transportation. The trip to orbit is analogous to the drive to the airport: You don’t need a 220+ mph supercar; you just need a nice, reliable Hyundai. We should focus the high-risk/high-reward technologies — especially when the “high risk” involves poisoning the fucking planet — where the high rewards are actually needed.

  36. 36
    Nerd of Redhead, Dances OM Trolls

    If our species just could escape the self-imposed straitjacket of radiation phobia…

    We’ll just have to make sure you are only a few hundred feet from the launch site. Put up, or shut the fuck up.

  37. 37
    frankensteinmonster

    My point is that we don’t need orders of magnitude better performance in the Earth-to-orbit arena: What we need, instead, is straightforward, operationally simple, sustainable transportation.

    yeah, right. the cost of several thousand dollars per kilogram is completely acceptable, sustainable. No need of something that gives you a few orders of magnitude more performance for the same money because we are all so super-duper rich here, that even such high cost simply does not matter :)

    Have they been given any real-world engineering demonstration, or do the exist only on a damp cocktail napkin in your jacket pocket?

    Yeah right. And because we are so content with what we have, we have no need to attempt to try something we haven’t used yet. We all know that the progress of the mankind comes through never using anything that has not already been used before.

    poisoning the fucking planet

    A planet is usually quite big. One launch every few years ( we are talking about tens of thousands tons of stuff, so we won’t need to launch very often ), could not possibly poison an entire planet. Unless the radiation phobia strikes again, and, like a friend of mine, you are willing to believe that every single radionuclide atom is a human killer.

  38. 38
    Bill Dauphin, avec fromage

    An interesting story for those who think SpaceX is just about “reinventing the wheel.” I’m the first one to say I’ll believe it when I see it, but I think it’s clear that SpaceX at least intends to be more than just another ELV satellite launch provider.

  39. 39
    Bill Dauphin, avec fromage

    frankensteinmonster:

    My point is that we don’t need orders of magnitude better performance in the Earth-to-orbit arena: What we need, instead, is straightforward, operationally simple, sustainable transportation.

    yeah, right. the cost of several thousand dollars per kilogram is completely acceptable, sustainable.

    And you assert that the shortest path to Earth-to-orbit cost reduction is to develop something like antimatter-pumped fusion, nuclear thermal rockets, or Orion-style nuclear explosive propulsion… for liftoff from the Earth’s surface? SRSLY? In what universe would the cost reduction (if any) from exotic nukes come sooner than cost reductions from improved chemical-based propulsion, improved mission architectures (e.g., airbreathing flyback first stages), and operational efficiencies?

    Have they been given any real-world engineering demonstration, or do the exist only on a damp cocktail napkin in your jacket pocket?

    Yeah right. And because we are so content with what we have, we have no need to attempt to try something we haven’t used yet.

    Where did I say we didn’t need anything new? Instead, what I said was the right “new things” to pursue for this application are nearer-term, evolutionary technologies rather than whizz-bang exotics. Mind you, I think the whizz-bang exotics are super fucking cool, but cool isn’t a good enough reason to commit staggering levels of development effort and funding. If we’re ever to travel routinely between the planets, or to even attempt interstellar flight (even robotic interstellar probes), we’ll really need those exotics… but we don’t need them, and should wait around for them, to make Earth-to-orbit transportation routine and affordable.

    poisoning the fucking planet

    A planet is usually quite big. One launch every few years … could not possibly poison an entire planet.

    So? What do you imagine the impact of a Challenger-like event (i.e.,. explosion of a launch vehicle high in the atmosphere) if the vehicle in question were powered by a fission-based nuclear thermal rocket?

    But it’s a moot point, anyway: Regardless of your disdain for people’s allegedly irrational fear of radiation, we do live in a democracy, and in a world increasingly made up of more-or-less democratic states, and I predict that convincing the public that firing nuclear rockets on the ground is a good idea (especially since the whole point would be to make it a routine event) will be an even longer-term project than developing the nuclear rockets in the first place.

    In short, I’d bet we’ll see private rocket-powered space yachts zipping around before we have nuclear launch technologies and a public willing to use them.

  40. 40
    Bill Dauphin, avec fromage

    Argh! @ImStillNotSeeingCommentNumbersandNoIDontWannaScrewWithMyCSS:

    …but we don’t need them, and shouldn’t wait around for them…

    FTFMe! <sigh>

  41. 41
    NJOsprey

    The researchers say there may be enough to implement a scheme using antimatter to fuel future spacecraft.

    So that’s where Zefram Cochrane got the anti-matter to power the warp drive on the Phoenix

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