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Comment by RK | Hacker News Reader

I call bullshit. The cost is not "very high", it's astronomically high.

My advisor also worked on creating antimatter traps at government labs, but none of the projects had any kind of defense related purposes.

There are only a handful of interesting research questions about antimatter that exist at reasonable scales. Most of those are either fundamental physics or medical in nature.

EDIT: Looks like there has been some Air Force funding for positron traps for defense purposes. Never underestimate the insanity of some generals. I think my physics comments still stand, though.

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I call bullshit. The cost is not "very high", it's astronomically high.

(Comments like this make me want to stop reading Hacker News.) Just because the "gunpowder" is expensive doesn't stop the production of containment vessels or delivery mechanisms:

http://articles.sfgate.com/2004-10-04/news/17447495_1_antima...

http://en.wikipedia.org/wiki/Antimatter_weapon

Additionally, "antimatter" can include positrons, which are much cheaper to produce than antiprotons.

My advisor also worked on creating antimatter traps at government labs, but none of the projects had any kind of defense related purposes.

Your advisor may not have been involved in all imaginable projects related to antimatter.

There are only a handful of interesting research questions about antimatter that exist at reasonable scales. Most of those are either fundamental physics or medical in nature.

Along with research into directly producing weapons, antimatter can also be used to initiate (micro)fusion, and has been researched for space travel: http://en.wikipedia.org/wiki/Antimatter_catalyzed_nuclear_pu...

While I kinda agree with the spirit of your comment (we'll get there someday), there's a few problems with the specifics.

A pure (or high percentage) positron weapon would be very hard to handle. The repulsive forces would be enormous. As in we have a hard time containing the equivalent mass of electrons. And that's without worrying about annihilation.

And really, I think RK's response was spurred on more by rubypay's tone/phrasing. The original phrasing easily sounds like we're on the verge of practical anti-matter weapons. Which we're not.

(Comments like this make me want to stop reading Hacker News.)

If that's not trolling, I don't know what is. I will remind the gentle readers that I even edited my post (with a tag) for correctness almost immediately.

Just because the "gunpowder" is expensive doesn't stop the production of containment vessels or delivery mechanisms:

Actually that's exactly why such a project doesn't make sense. Kind of like building a fancy castle to put your Holy Grail in before you've found it. Read any of the articles or commentaries based on actual science, they say that such a weapon is so far fetched from an engineering stand point, that it's not worth pursuing.

Ref.: http://public.web.cern.ch/public/en/Spotlight/SpotlightAandD...

Or the same wikipedia article you linked:

http://en.wikipedia.org/wiki/Antimatter_weapon

Your advisor may not have been involved in all imaginable projects related to antimatter.

Thank you for ignoring my edit.

I'm not saying that any of this is impossible, just that it's horribly impractical, needing probably an order(s?) of magnitude more than Manhattan Project level of effort.

No knock on you and your research which seems pretty cool, but it really saddens me that motivation for government spending into this research is to build a bigger, better, more lethal weapon.

I wish the energy supply rationale were the real motivating factor for funding here.

Antimatter munitions scare me personally because they're a fail-deadly weapon. If the positron trap fails it goes kaboom. If a thermonuclear bomb fails in any way except a precisely calculated implosion you at worst you get a fissle, at best a guy in Whateveristan in the year 2040 gets his roof collapsed by a slightly radioactive dud.

I hope, the only thing these are being designed for is some gamma-ray laser for a new ground based Star Wars system and not as an actual munition of any sort. The complications are astronomical, especially given that gamma-rays are the EMP-producing portion of a nuclear reaction. An positron trap light enough to be contained in a weapon going off without a tamper to produce an explosion from the gamma-ray heating could be devastating for a modern society.

I'd never call playing god with this shit, I call playing stupid.

I'm pretty sure I've read somewhere that if you did just dump a quantity of antimatter (e.g. by turning off the containment device) you wouldn't get a nice explosion - more a long drawn out messy fizzle.

I would guess that a antimatter bomb would have to a similar design to fission or multi-stage devices where things are held together long enough by implosion for a significant proportion of the fuel to react.

I've done the math, you get an explosion quite rapidly. In a matter of nanoseconds the reaction of air in contact with the surface of the anti-matter chunk will release enough energy to vaporize the anti-matter and transform it into a growing ball of hot gas/plasma thoroughly mixed with matter, annihilation of the anti-matter completes in a matter of micro-seconds after that. This is if the anti-matter is just sitting in the open air, if it comes into direct contact with solid matter the process would probably proceed faster.

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