1) Hurrah! I have his paper on the economics of interstellar trade...

2) the first link should presumably go to http://nobelprize.org/nobel_prizes/economics/laureates/2008/ - at present it just points to ML.

Something isn't right with the first link, but huzzah nonetheless!

I expect the right-wing blogosphere to break out in a fit of gnashing of teeth.

First link fixed--I had left out the equal sign after "a href". That's what I get for posting before my first cup of tea.

and yet he's shrill. What are the odds.

Buckets of win.

Alex Ross gets a MacArthur "Genius" grant (his book The Rest is Noise is terrific) a few weeks ago, and now this. My favorite columnist/bloggers are finally getting their due.

Fragano @ 3 -- I consider that a bonus feature.

He's going to be insufferable for months. Oh, wait...

Congratulations to Prof. Krugman!

The Nobel committee's own page on Krugman. Their technical overview of the work (PDF). Their more-accessible summary (PDF).

Worldcon GOH next?

*is gleeful* Very cool.

From Crooked Timber:

We at CT have a more parochial reason for cheering this outcome. Paul has generously agreed to take a part in a CT seminar on the work of Charles Stross, which should be published in the next month or so. Without giving too much away, there are some Nobel-related insights in his contribution.

All Hail the Shrill One.

Wall Street must love this news. Dow up 400 ...

Very cool, although I certainly don't understand the work that was done. Economics is usually over my head.

And, while it is cool, I always get annoyed that The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel is described as the Nobel Prize in Economics, not so much at the people describing it thusly, but at the people who named their own prize so it was certain to be interpreted as one of Nobel's prizes. Making your own prize for achievements in economics is great, but don't try to ride on the coattails of Nobel.

I'm very happy for him, but I'm even happier that during an economic crisis Paul Krugman just got handed a enormous soapbox to talk from.

Micah @ 15:

As someone pointed out on one of the Crooked Timber threads related to this award, the Nobel Foundation sees no problem in listing the Economics award as one of "the" Prizes, even while they point out that it was not one of Alfred Nobel's original designations. (And the Economics Prize is selected by the same entity -- the Royal Swedish Academy of Sciences -- that selects the Physics and Chemistry winners.)

I enjoyed Daniel Davies' footnote to his own Crooked Timber post on the Krugman news:

[1] blah blah blah Sveriges Riksbank. Nobody cares, you know.

Besides the honor, there's the little matter that the Prize also includes a cool $1.4 million.

So it's sort of ironic that Krugman has won at a time when there's scarcely a bank left standing where he can open a safe account.

I hope he's got a really big mattress.

Krugman as a Worldcon GoH or Special Guest? Oh, I would love to be working on programming for that one. Bet you we could get Brad DeLong to show up...

The question I have is, does this mean Krugman has achieved his life's ambition, and he *is* Hari Selden?

How cool is that? I've had the RSS feed to his blog on the same iGoogle tab as Making Light for a while now; that's about as economically prescient as I'm ever likely to be. heh.

I saw him on a roundtable TV discussion recently, and he was as sharp in person as he is in print.

This is certainly interesting:
http://www.princeton.edu/~pkrugman/interstellar.pdf

Woot! Krugman's one of my go-to web sources on what's going on with US (and to an extent, world) economy currently. Now I can quote an economy Nobelist in arguments!

I started dancing when I heard, which was not a good idea, as I was in the shower at the time.

Congratulations to Professor Krugman!

The prize was for his work back in the 1980s, to be sure, but the timing of it was clearly political. The right wingers will be grumbling about "damn furriners interfering in American politics blah blah grumble whine," to which I will say "IN YOUR FACE!"

I think he's the most fannish Nobel Laureate yet (Ben Yalow's mom never seemed all that fannish to me).

You can watch heads exploding (although not the site owners, who each give props to Dr K) in real time at http://www.marginalrevolution.com/marginalrevolution/2008/10/paul-krugman-wi.html#comments

Teresa @ 20... We could then have Krugman emcee the masquerade. I wonder if he'd begin with an impossible wish like Wil Maccarthy did at Denvention's.

In #12, Kip Manley quotes Crooked Timber:

We at CT have a more parochial reason for cheering this outcome. Paul has generously agreed to take a part in a CT seminar on the work of Charles Stross, which should be published in the next month or so. Without giving too much away, there are some Nobel-related insights in his contribution.

Given my recent activities, I initially parsed CT as "contraterrene," which would not be out of place in a discussion of Charles Stross.

Wow, I didn't know that term was used outside of science fiction! You know, Seetee Shock and its kindred. Do you who work with antimatter on a regular basis actually use that term when doing, you know, real science?

This news made me very happy.

Thanks for the links to his SF comments. I consider the SF-reader category a false karass, but it is always a pleasure to find someone who can talk intelligently about SF. That's a much smaller group.

This is what he really got the prize for.

Teh kittehs no leik Sarah.

Krugman showed us this. He brought Lolcats to the Grey Lady.

Love, C.

I generally roll out of bed (literally, using my hand and hip as a pivot . . . chiropractor advice) at 6:31 am, after listening to the "funny news" item on NPR.

I stayed a few extra seconds and heard the Nobel news.

That was a very nice way to start the day.

It strikes me that President Obama's cabinet could feature several Nobel prize winners.

Yeah, can't say we've seen many Nobel laureates within a mile of Bush (except, of course, for the required invite to the White House). He's probably still not over Al Gore's Nobel win!

#33: I won't do the guy of favor of even looking up his name, but there's an editorial cartoonist who seems to be in charge of crass partisanship and ugly caricatures of the left.

When Gore got his Nobel, this guy drew an oval office meeting scene. Gore, with a medal hung around his neck, was overweight, hook-nosed, and oafish looking; a spritish-looking Bush was posed next to a big award trophy labeled "Leader of the Free World."

It struck me as the most clueless, ungracious way possible of marking the occasion.

Micah, #15: There's an an intelligent layman's summary (PDF) of the work and its background over at the Nobel site, also a short audio interview (WMP or Real) with Krugman. There are two bodies of work mentioned: the first is a highly successful model of international trade which takes into account a human desire for a diversity of goods. The second extends this work into analysis of the geographic distribution of wealth. He is also, as his columns show, one of the great teachers of the field. I recommend the interview to everyone--it's short & worth the trouble.

His work's well worth reading (what of it I understand, which is basically the public stuff on the web). Congratulations to Professor Krugman!

At least six writers of science fiction have won the Nobel Prize in Literature: George Bernard Shaw (Back to Methuselah), Bertrand Russell (Nightmares of Eminent Persons), Harry Martinson (Aniara), Sinclair Lewis (It Can't Happen Here), William Golding (The Brass Butterfly), and Doris Lessing (the Canopus in Argos pentalogy).

Rudyard Kipling, "With the Night Mail."

Mind you, a lot of better writers of science fiction have been passed over, including Stanislaw Lem, Italo Calvino, Jorge Luis Borges, Aldous Huxley, and Philip K. Dick...

Wow, I didn't know that term was used outside of science fiction! You know, Seetee Shock and its kindred. Do you who work with antimatter on a regular basis actually use that term when doing, you know, real science?

Heck, no. But evidently you haven't seen this and this yet.

I learned how antimatter entered the realm of science fiction, who coined "contraterrene," and what Jack Williamson's carbon copies looked like.

Timeline here, which led to my article. Further notes here and here.

No, I hadn't seen any of that. I've read it all now. Very cool stuff!

This is probably a dumb question: I assume that protons and antiprotons are charge-attracted to each other, but if you had a substance made of antimatter iron, and another made of regular iron, both electrically neutral, would there be a force of attraction between them (other than gravity)?

And if so, would the force of attraction be enough to hold them together long enough to allow for total conversion, or would they fly apart after only a small amount was converted? I don't know either, Xopher.

#41: No, the chunks of iron and anti-iron would only be attracted by gravity. (Or, possibly, ferromagnetism, if either or both happened to have aligned magnetic domains.) In fact, anti-iron should have exactly the same material properties as iron.

In any case, there is no special force whose only operation is to attract particles to anti-particles and vice-versa.

Let me rephrase slightly--because the weak force very slightly distinguishes between matter and anti-matter, at very short ranges and very high energies, and because anything that makes a distinction can be expressed as a force in the quantum mechanical math, it is legitimate to say that there is a sort of force between matter and anti-matter.

However, if you're talking about chunks of matter and anti-matter, you're on a distance scale that's far larger than the range of this kind of weak force side effect. Like ten orders of magnitude larger.

Meanwhile, the IgNobel Prizes have also been announced. Surely this response to them deserves a Fluorospheric link?

Xopher writes in #41:

This is probably a dumb question: I assume that protons and antiprotons are charge-attracted to each other, but if you had a substance made of antimatter iron, and another made of regular iron, both electrically neutral, would there be a force of attraction between them (other than gravity)?

No, assuming (since you ask about iron in particular) they aren't magnetized.

In Jack Williamson's Seetee stories, the asteroid miners manipulate meteor-type antimatter iron with magnetic fields, and eventually develop a set of remote-control anti-iron machine tools with which to work raw anti-metal.

E.E.Smith's Negasphere, another early example of antimatter, uses created antimatter, which involves the Galactic Patrol cleaning out an Asteroid Belt. It also has a few odd properties, and the energy levels the Patrol use to create the thing are mind-boggling.

Chapter 10 of Gray Lensman

Smith's negaspheres seemed to be an odd combination of antimatter and black holes. He also got their responses to force wrong, if they're meant to be antimatter -- antimatter does not respond oppositely to, frex, magnetism. (Smith had negaspheres attracted by pressor beams, and repelled by tractor beams and gravity.)

Doc Smith's negaspheres appeared in Gray Lensman, which began serialization in October 1939.

The earliest example I know of antimatter in SF is John D. Clark's "Minus Planet," in Astounding for April 1937. Astronomers discover an antimatter planet that threatens to collide with the Earth. Using beer-and-slide-rules superscience, they maneuver the Moon into its path to annihilate it.

Asimov called his robotic brains "positronic" in "Reason," April 1941, but antimatter physics doesn't figure in his stories and he later admitted that he used the word because it sounded cool.

So Jack Williamson didn't write the very first story about antimatter. There wasn't room to cover this in my article. I claim nevertheless that, along with three sequels, "Colllision Orbit" planted antimatter firmly in the landscape of science fiction. His comic strip with Lee Elias, "Beyond Mars," also brought seetee to the attention of funnies-reading New Yorkers in the 1950s.

Bill Higgins @ 49... beer-and-slide-rules superscience

This reminds me that I haven't watched Val Kilmer's Real Genius in quite some time.

that energy equivalent to the annihilation of at least six hundred thousand tons per hour of material was being hurled into the center

That's how the Galatic Patrol makes a negasphere.

That's around 15 zettawatts.

For the prototype rig.

Makes FermiLab and CERN look a little puny.

On Newshour with Jim Lehrer last night, Krugman said that he was inspired to become an economist by reading The Foundation Trilogy.

So, we put him on the Asimov panel ...

#52: For their next trick, the Galactic Patrol directed the total output of the sun into a laser beam.

Think big.

(Smith had negaspheres attracted by pressor beams, and repelled by tractor beams and gravity.)

In Smith's defence, when someone invents a tractor or pressor beam, only then will we have definitive proof of how it effects antimatter.

Nevertheless Smith's handling of antimatter is masterful compared to the film The Giant Claw in which an antimatter bird the size of a battleship attacks the earth. Since the film is 18 years later than Gray Lensman they have less excuse.

#55: antimatter bird the size of a battleship

Reminds me of an old 1960s Justice League of America:

"TO TOUCH ANTI-MATTER MAN IS TO RISK INSTANT DESTRUCTION!"

with a cover of Batman slugging said contraterrene entity.

Well, he's Batman ...

Jon Meltzer @ 53... Think big.

At some point, didn't the Galactic Patrol carry a whole solar system from our galaxy to another?

Serge @56: I think they just moved planets. IIRC, it was a planet of good guys in the evil Boskone galaxy that got moved to our galaxy first, which gave the Patrol the idea to use dirigible planets as weapons.

NelC @ 57... gave the Patrol the idea to use dirigible planets as weapons

And some Led Zeppelin?

#55: Maybe it was ANTI Batman. I guess the bizarros are also made of antimatter?

PNH @ 18:
I enjoyed Daniel Davies' footnote to his own Crooked Timber post on the Krugman news:

[1] blah blah blah Sveriges Riksbank. Nobody cares, you know.

I, for one, do, because I think calling that price a Nobel Price is a way of making the whole field of economics look more respectable than I think it is. Nothing against Prof. Krugman, though, who seems to be one of the saner people there (if you overlook his apparent support of the IMF/World Bank model of development). And, well, if literary fiction can have a Nobel price, then I guess economics can have one, too.

Laurie Mann @ 33:
Yeah, can't say we've seen many Nobel laureates within a mile of Bush

As far as I know, some of the previous winners of the economics price preached the same kind of economic policies as any Republican hack.

#41: No, the chunks of iron and anti-iron would only be attracted by gravity. (Or, possibly, ferromagnetism, if either or both happened to have aligned magnetic domains.) In fact, anti-iron should have exactly the same material properties as iron.

Might you not get some very short-range "electrostatic" attraction, due to the fact that the electron clouds that make up the "surface" of the iron would be attracted to the positron clouds making up the surface of the anti-iron?

I'd imagine this effect wouldn't really matter unless you brought the iron and anti-iron to within a few (tens of?) times the typical size of an iron atom, but it would probably be stronger than any weak-nuclear-force effects.

ObPoetry:

Perils of Modern Living
Harold P. Furth

Well up above the tropostrata
There is a region stark and stellar
Where, on a streak of anti-matter
Lived Dr. Edward Anti-Teller.

Remote from Fusion's origin,
He lived unguessed and unawares
With all his antikith and kin,
And kept macassars on his chairs.

One morning, idling by the sea,
He spied a tin of monstrous girth
That bore three letters: A. E. C.
Out stepped a visitor from Earth.

Then, shouting gladly o'er the sands,
Met two who in their alien ways
Were like as lentils. Their right hands
Clasped, and the rest was gamma rays.

Serge, in post #56: At some point, didn't the Galactic Patrol carry a whole solar system from our galaxy to another?

You may be thinking of Project Rho, from Skylark DuQuesne, which involved teleporting planets from Galaxy A to Galaxy B (and stars from Galaxy C to Galaxy A for a campaign of massive genocide).

OK, here's a non-stupid question: Suppose you have two 1 kg spheres, one of iron, one of anti-iron, not magnetized, at 2.7° Kelvin (i.e. same as space) and they are moving directly toward each other (center to center) in zero gravity, inertial at 1 meter/second relative speed, what happens when they collide?

Specifically, are they both entirely annihilated, releasing 2kg * c² of energy? Or is some part of them annihilated, and some or all of the energy becomes acceleration, pushing them back apart? In the second case, is there any way to calculate how much mass would be annihilated, how much energy would be released or transformed as kinetic, and how much as heat, gamma rays, etc? And do the properties of the particular materials (in this case iron and anti-iron) matter?

Tom asked this question at 42, but I decided to give precise details in case calculation really is possible.

And something else I've never understood: in the term c², I understand what sec² are, it makes it an acceleration, which makes sense if you're talking about energy. But if you square meters/second, don't you get an area for the meters term? Gram-distance per second per second makes sense to me; it's an energy equivalence for a force of acceleration. Gram-area per second per second doesn't.

Could you explain either how that makes sense, or what my mistake is in squaring the meters, or whatever is going on there?

I expect that the result would be different than that of two sheets one atom thick, perfectly aligned, approaching each other. I also expect that the two spheres would accelerate toward each other, so that the collision would occur sooner than the initial projection based on their starting speed. That's just intuition, though, not number crunching, on my part.

OK, here's a non-stupid question: Suppose you have two 1 kg spheres, one of iron, one of anti-iron, not magnetized, at 2.7° Kelvin (i.e. same as space) and they are moving directly toward each other (center to center) in zero gravity, inertial at 1 meter/second relative speed, what happens when they collide?

This is actually a really difficult question. You'd get annihilation at the point of contact and a blast of radiation, which would heat up and vaporise the iron and anti-iron immediately around the point of contact - then you'd get more annihilation as the clouds of vaporised material collided with each other. And, thanks to Newton, the two spheres would be propelled apart again by the blast. As for how much energy would be released - no idea.

And something else I've never understood: in the term c², I understand what sec² are, it makes it an acceleration, which makes sense if you're talking about energy. But if you square meters/second, don't you get an area for the meters term? Gram-distance per second per second makes sense to me; it's an energy equivalence for a force of acceleration. Gram-area per second per second doesn't.
Could you explain either how that makes sense, or what my mistake is in squaring the meters, or whatever is going on there?

E = mc² means, as you realised, that you end up with a value for energy expressed in kilogram metres squared per second squared. Why is energy measured in this weird collection of units?

Think of energy in terms of gravitational potential energy: the amount of energy it takes to lift an object up onto a shelf is equal to the height of the shelf (metres) times the weight of the object, OK?

And the weight of the object is equal to its mass (in kilograms) times the strength of gravity (expressed as an acceleration, so in metres per second squared).

So energy equals height (metres) times mass (kilos) times gravity (metres per second squared) = kilogram metres squared per second squared.

Why would they accelerate toward each other? At 1 kg their gravity wouldn't be significant, and we've established that no other force of any significance would act to draw them together.

At any rate, I meant that the distance between their centers was decreasing by 1 meter/second at the moment of impact. And I did specify that they were inertial, not accelerating or decelerating.

I read that as contraterrine, and wondered what the antithesis of an earthenware cooking dish would be...

Xopher @ 64:
And something else I've never understood: in the term c², I understand what sec² are, it makes it an acceleration, which makes sense if you're talking about energy. But if you square meters/second, don't you get an area for the meters term? Gram-distance per second per second makes sense to me; it's an energy equivalence for a force of acceleration. Gram-area per second per second doesn't.

It might be better to think of it as force (gram-distance per second per second), multiplied by how much distance you apply the force over. That is, in fact, the definition of work, which is a form of energy: force multiplied by distance. Think about applying a force to an object (say, pushing something by hand, or : if you maintain the same amount of force, the larger the distance over which you apply the force, the faster whatever it is will end up going = more kinetic energy.

(This is another way of expressing what ajay just said.)

#66
Or Newton-meters: kg*(m/sec**2)*m
(mass times acceleration times distance over which the mass is being accelerated)
which is Joules: energy

It's not the antithesis of the dish per se. It's an attitude of political opposition to such cooking dishes.

For example, the Nicaraguan Contraterrines committed many terrorist acts, destroying earthenware dishes in homes and shops. They were called "the bulls" for this reason. The covert support they got from the US mainly came ultimately from Dow Chemical, who supplied them not only with money and weapons but with free Corningware™.

AH! I was trying to keep the meters together, and getting an area, and that made no sense, but kilogram-meters per second per second per meter makes lots more sense.

Thanks for explaining so clearly. I've never understood that before. Wow, new knowledge sure feels good going into my brain. Yum.

For example, the Nicaraguan Contraterrines committed many terrorist acts, destroying earthenware dishes in homes and shops. They were called "the bulls" for this reason. The covert support they got from the US mainly came ultimately from Dow Chemical, who supplied them not only with money and weapons but with free Corningware™.

Unfortunately, given the poor utensil-rights record of the Nicaraguan government at the time, its attempts to publicise the wrongdoing of the Contraterrines was dismissed as simply a case of the pot calling the ket

*THUMP*

(ajay's unconscious body is dragged off stage left by the stealthy figures of the Society for the Promotion of Humour and the Suppression of Puns)

ROFLMAO, ajay! You are precious beyond rubies!

I have read that, although there is no compelling theoretical reason why it shouldn't, it is an open question whether antimatter responds to gravity the same way that terrene matter does.

Xopher @ 71... ajay @ 73...

"Cardinal! Bring out... the seetee settee!"

cd @ 63... teleporting planets from Galaxy A to Galaxy B (and stars from Galaxy C to Galaxy A for a campaign of massive genocide)

This makes Greg Bear's Moving Mars seem lame.

#71: The covert support they got from the US mainly came ultimately from Dow Chemical, who supplied them not only with money and weapons but with free Corningware™.

At the time it was claimed that support did not come from covert sources, but through proceeds from public social events called "Contra Dances".

Those dirigible planets from the Lensman series get even more impressive when the Patrol starts bringing planets over from a dimension where the planets have intrinsic (inertial, rather than inertialess) velocities of greater than light velocity. Imagine two of those ramming into your planet from opposite sides....

The discussion of how two relative anti-spheres of iron would react to each other leads me to think about how one would design shaped-charge explosives based on a matter-antimatter interaction. Someone with more experience than I could have a great deal of fun with this....

Matter-antimatter reactions result in gamma rays. These pass through many materials without much interaction. A shaped charge might be something like

-----------------
A "explosive" B
-----------------

The case (---) would be some kind of very sturdy material transparent to gamma rays. It wouldn't have to last long.

"A" would be something opaque to gamma rays and easily vaporized. Essentially, propellant.

"B" would be a plug, curved on the left side, that is very, very sturdy. "A" vaporizing would drive it into the target, which hopefully is to the right.

Zack @75: Small amounts of antimatter have been created and collected. I would think they'd have had the opportunity to observe the effect of gravity on their samples.

A few hundred atoms of antihydrogen have been produced at a time; a few atoms of antihelium have been produced, ever. Atomic motions in gases are pretty random, so it's hard to judge the effects of gravity, especially given the minuscule amounts. The particles can be contained by electric/magnetic systems if the atoms are charged, and by resonant laser systems if they're neutral, but either way, when they're contained they're suspended and so not free to move much in response to gravity... and they still can't be contained for very long for purposes of study.

I don't think we'd be able to determine the effects of gravity on such tiny quantities of normal-matter hydrogen and helium.

Xopher, #64: provided the spheres could be contained, yes, there would be total annihilation. I believe the radiation emitted would be photons with a black-body spectrum, probably heavily weighted towards gamma rays, though the energies involved are so high that I suppose other sorts of particles might be emitted. But containment is the problem; in a fission bomb, IIRC, a great deal of design effort is spent to ensure that the critical mass stays together long enough to actually create a substantial explosion. The problem would be similar in your proposed anti-matter "bomb"--the plane of contact between the spheres would be an explosion, so the spheres would be trying very hard to blow apart. I'm not sure if any calculation could predict the result.

Rob Rusick writes in #81:

Zack @75: Small amounts of antimatter have been created and collected. I would think they'd have had the opportunity to observe the effect of gravity on their samples.

You'd think so, wouldn't you? But in fact such a measurement is very hard.

We produce and capture antimatter (positrons, antiprotons, or more recently neutral antihydrogen atoms) in equipment that uses electric and magnetic fields.

Gravity is about forty orders of magnitude weaker than electromagnetism.

So the forces we're using to produce or confine antiparticles are immensely stronger than the force of gravity acting upon them. Gravity may be utterly overwhelmed by minuscule variations in the forces exerted by electrodes, magnets, laser beams or whatever. You can see why making an accurate measurement might be very difficult. I believe there are efforts at the CERN antiproton facility to do so.

The Particle Data Book, on page 2 of the chapter on protons and antiprotons, suggests that the inferred upper limit on the difference between proton mass and antiproton mass-- as far as gravity is concerned-- is about one part in a million or one part in ten million. (Their inertial mass is identical to one part in ten billion.)

So Zack is correct in thinking that the experimental evidence is somewhat fuzzy. We're reasonably sure antiparticles don't fall up, but it's not something we know with great precision.

Yet.

Gravity is about forty orders of magnitude weaker than electromagnetism.

Xopher, I'm going to inflict the 'other' metric system on you here.
You get the dyne-cm
g*(cm/sec**2)*cm
which is also called
erg.

(Cue the bad jokes! I'd do the one my physics teacher used, but it's visual and the bandwidth of this keyboard isn't nearly good enough.)

"Erg," said the centimeter. "I'm dyne!"

Randolph, you misunderstand my question. I forgot to say in vacuum, though the presence of a 1 kg mass of antimatter in AIR is unlikely. But my question excluded any kind of containment; I was asking whether two such spheres would annihilate each other instantly, or be pushed apart by the annihilation of a relatively small amount of mass.

NelC @57:
That would be the planet Medon. Not moved by the Galactic Patrol; discovered by the GP just before the Medonians fired up their super-Bergenholms and headed out of the Second Galaxy.

(I can't remember where I encountered "stellation", but I recognize and remember this immediately. Anyone got brain bleach?)

P J Evans @ 86... erg

You rang?

My intuition is that the two spheres would be repelled pretty quickly, with relatively small amounts of their mass annihilated. But intuition is all it is.

Hmm. A fission or fusion reaction produces lots of atomic and subatomic fragments which interact strongly with surrounding matter, producing heat and direct-impact force. A matter/antimatter reaction generates only extremely-high-energy photons, at least directly. I don't know how strongly those interact with the nearby matter to generate heat or transfer momentum, or to create more particles.

91: this paper on How To Build An Antimatter Rocket Ship might help. It's from Nasa.
Interestingly, a lot of the energy from annihilation would be given off as gamma rays and exotic particles, as you suspected. But most of the Antimatter Rocket Ship designs seem to assume that you could convert a lot of the energy by catching that in a tungsten block - and the iron and anti-iron spheres would presumably work just as well. So a chunk of each sphere would soak up the radiation and vaporise.
The blast of that happening might, of course, fragment the spheres completely - in which case you'd have two clouds of fragments and vapour occupying the same space, and a blaze of secondary annihilation explosions.
Don't try it at home.

ObThis is Just to Say

I have annihilated
the mesons
that were in
the accelerator

and which
you were probably
planning to use
in experiments

Forgive me
they were delicious
so charming
and so strange

[cute kitten]

I MADE YOU A HIGGS BOSON
BUT I EATED IT

Why is it that I understand the economics in this post better than I understand the physics?

[Cat in improbable pose]

INVISABUL QUARK

Since you mention it, the old TV series Quark has just been released on DVD, and my copy is probably waiting in my mailbox at this moment.

As it happens, matter-antimatter reactions do not necessarily result in pure annihilation into gamma rays. It depends on the particles involved.

Leptons (electrons and their cousins, the mu & tau particles, and the various flavors of neutrinos) do annihilate to gammas with their antis. Baryons like protons and neutrons, which are made up of three quarks, can't do that. A proton and an antiproton react to form 3 pi-mesons: a pi-minus, a pi-plus, and a pi-zero, which fly off with the energy left over because the total rest mass of the mesons is less than that of the proton + antiproton. Annihilation doesn't occur because there are 6 quarks taking part in the reaction, and they're not in quark-antiquark pairs.

That's why a Forward antimatter rocket could be so efficient: the pi-minus and the pi-plus, being charged, can push against by a magnetic field which acts as the rocket's thrust venturi. You lose the pi-zeros, but it's still a lot easier to use pi-mesons as reaction mass than it is to use very hard gamma rays. Also, the pi's decay after a few hundred meters into other things (I can't recall what, offhand), whereas gamma rays, especially in a collimated beam, can do damage to matter for thousands or millions of kilometers.

What quarks make up the proton and antiproton? I'm not clear on whether their charge is a quark or not (I'm an igneous runt* when it comes to this stuff).

Is there an antiquark for every quark? If so, what WOULD be the baryon made up of the antiquarks of the quarks that compose a proton? Or is that a nonsensical question?

Feeling stupid again. Somebody smarten me up with some new knowledge. (Or as The Wire said, "Hungry! Hungry!")

*"What else floats?" "Very small rocks!"

#99

The proton consists of two up quarks and a down quark, for a net charge of +1. (The charge of an up quark is +2/3; that of a down quark is -1/3). An antiproton, unsurprisingly, consists of two anti-ups and an anti-down.

The neutron consists of two down quarks and an up quark. Anything made of three quarks is a baryon; weirder[1] baryons consisting of quarks other than up and down are not stable, and most permutations have not been observed.

[1] Word chosen to avoid confusion because "strange" is a technical term in discussions of quarks.

Then what did Bruce mean by saying the quarks in a proton/antiproton collision aren't in quark/antiquark pairs? Sounds like they are.

#101
Two triplets, not three pairs.

But can't each of the particles in one triplet do a mutual annihilation with its corresponding antiparticle in the other triplet? Or is it that after that happens with one particle from each triplet, the remaining two particles in each triplet do something weird instead of continuing the annihilations?

Joel, the quarks in each are bound together by Magical Forces, so they have to interact as a group. At least that's my understanding.
Well, not the magical part. It just looks like magic.

(Partcle physics isn't my field, but I read Science News, and I used to read Scientific American, before it got all flashy.)

Joel, The "magical forces" PJ mentions get into the deep voodoo of quantum chromodynamics (in addition to flavors -- up, down, etc. -- quarks come in "colors", and each baryon needs one each of red, blue, and green (or anti-red, anti-blue, and anti-green). Basically the strong force is really, really strong, and once bound up into baryons those quarks aren't going anywhere. QCD is way over my head, though.

Re proton-antiproton annihilation:
In my limited understanding, the main thing which makes proton-antiproton (or neutron-antineutron) collisions complicated is the fact that quarks (and antiquarks) are quite massive, and thus quark-antiquark annihilation produces a lot of energy, and that energy can result in a lot of different particles being produced as a result; some of these particles are unstable, and then decay (quickly) into still other particles. If there's a lot of kinetic energy involved as well -- e.g., the proton and antiproton collide at very high speeds -- then that extra energy is also available, possibly allowing the creation of even more particles.

There's a nice example here of what can happen when a quark and its antiquark annihilate (in a proton-antiproton collision) at high speed. So, yes, you do get quark-antiquark annihilation when protons and antiprotons collide -- but that means a lot of energy, which can be traded for a lot of different possible particles.

The usual scenario for electron-positron annihilation is a pair of gamma rays, simply because the energy involved isn't enough to allow creation of other "matter" particles. Crudely speaking, you'd have E_total = m_e c^2 + m_e c^2 + E_kinetic_initial = Sum(m_? c^2) + E_kinetic_final, where m_e is the rest mass of an electron or positron and m_? is the rest mass of some particle that might be created. Unless E_kinetic_initial is very large, you're stuck with creating particles which have m_? less than m_e -- of which there aren't any except neutrinos. But if you run electrons and positrons together with enough extra energy (E_kinetic_initial), then you can get other things, such as D+/D- mesons.

Peter Erwin @ 106... the main thing which makes proton-antiproton (or neutron-antineutron) collisions complicated

What about collisions between money and antimony?

107: or, indeed, pasta and antipasto?

Then there was the situation when Natal & Antenatal met; it was particularly … which? Pardon? Oh, right …

Serge @ 107:
Well, meet me where the antechamber joins the chamber, and I'll show you...

(The funny thing was that I was thinking of throwing in a monetary metaphor in my post, but decided it was getting a bit long...)

This is all just amazingly cool. I don't have any more questions for now, but I want to thank everyone for feeding my brain hunger and making me smarter.

When I conquer the galaxy, count on palaces.

Meanwhile, at the university's lab, students turn the accelerator to full power and hurl their thesis at an antithesis.

Serge #112: Thus annihilating the professor? (I've felt, on occasion, that I've had the responsibility for running the senior antithesis course for my department. This included reading a document in which a student insisted, despite repeated correction, that Usama bin Ladin was 'an Arabic'. Suicide has been contemplated.)

111: when you conquer the galaxy? You, a puny human, who only learned how a simple antimatter annihilation bomb worked just a couple of days ago?

Ha! I think not!

Bruce Cohen, #98: duh. Yes, that makes sense.

ajay 114: Play right into my hands, o Overconfident One. You see me as a weak and feeble human, but I have the heart and stomach of a galactic monarch, and a monarch of the Milky Way too.

Scorn upon the Kzinti, or any race of aliens, who dare invade my realm!

When I conquer the galaxy, count on palaces.

Dibs on the Lagoon Nebula.

(Waterfront property, as it were.)

It will be fascinating to see if he goes back towards objectively applying economics or sticks to the "if the Republicans do it it must be wrong so I'll find a new rationale to be shrill about."

After all, he's highly unlikely to get a second one, so he doesn't have to play to the Swedish.