Just a few minor technical errors here
Posted on 11/18/2010 5:45:05 AM PST by markomalley
So - Dan Brown's turgid blockbuster Angels and Demons, in which a nefarious papal official nicks a vial of antimatter from CERN as part of a complicated scheme to become Pope by menacing the Vatican with explosive destruction. Twaddle? Or actually a perfectly feasible plan ripped from today's headlines, style of thing?
Just a few minor technical errors here
We here on the Reg particle-meddling desk naturally have no interest in the arcane Vatican rules of succession, the putative Illuminati secret society, the likelihood of finding a priest in the Pope's inner circle who would be capable of flying a helicopter etc.
We merely bring the matter up as it turns out that in fact there really is a team of scientists at CERN - the Organisation (formerly Conseil) Européenne pour la Recherche Nucléaire - striving to contain unprecedented amounts of antimatter: and they have just announced a major success in this extremely difficult undertaking. Could it be that Dan Brown has actually got one right? Would a tiny, pocketable amount of antimatter really be sufficient to rip the guts out of Rome in a blast equivalent to that of a small nuke?
On the face of it, yes. Antimatter reacts with normal matter to convert the entire mass of both into energy; it is the most powerful type of explosive possible, easily capable of making a global thermonuclear war look like angry cockroaches lighting their farts at each other.
Just a third of one measly gram of antimatter reacting with matter (for instance with the walls of its containment vessel) would cause a 15-kilotonne blast equivalent to that of the atom bomb which destroyed Hiroshima in 1945 - surely enough to wipe out the Vatican and quite a lot of Rome too.
QED: everything you read in Dan Brown books is true. Better still, the incomparably superior fiction of Star Trek might also be on the verge of becoming reality with antimatter at last available as a power source. As all Trekkies know, the Enterprise's warp drives were powered by a matter/antimatter reaction.
Whoa there! Not so fast.
First off, we're sorry to report that the international boffins of the ALPHA collaboration at CERN have succeeded in trapping only a sub-ultra-minuscule amount of anti-hydrogen, not even close to the milligrams range.
"We've been able to trap about 38 atoms, which is an incredibly small amount, nothing like what we would need to power Star Trek's Starship Enterprise - or even to heat a cup of coffee," says Rob Thompson, Canadian physics prof and member of the ALPHA group.
He's not kidding: each atom of nega-hydrogen masses something like 1.67x10-27 kg. Thirty-eight of them converted to energy according to Einstein's famous and pleasingly simple-enough-for-hacks equation E=mc2tells us [1] that should a rogue Vatican official manage to abscond with Thompson's antimatter stash and annihilate it in the heart of the Catholic Church, he would liberate approximately 11 billionths of a single measly joule. And in fact it's even worse than this: the ALPHA experiment didn't contain its 38 anti-atoms all at once.
Thompson and his fellow boffins don't care, of course - funnily enough they have no interest in blowing up the Vatican and it would seem only a mild one in powering possible future starships. Rather, they hope by examining antimatter carefully to work out answers to such puzzles as where all the antimatter actually is - theory suggests there ought to be as much of it as there is regular matter, but actually it is outrageously rare.
And it certainly wasn't easy to get together even a few atoms of the stuff. Charged antiparticles - for instance an anti-proton or an anti-electron - can be snared relatively easily using electromagnetic fields. The boffinry community managed this ages ago. As the mass of an atom of antihydrogen is almost all in the single anti-proton nucleus anyway, you might say the heck with the positron (anti-electron) and just go with a load of antiprotons.
The downside of that, according to this excellent article [2] by ALPHA scientist Jeffry Hangst - who perhaps worryingly was evaluating the possibility of delivering a functioning antimatter bomb, not to the Vatican, but "to the offices of your national funding agency" - is that containing charged antiparticles requires huge volumes of space.
Far from a handy portable vial, in order to contain a single milligram of antiprotons - good for a reasonably major blast equivalent to 50 tonnes of TNT - you would need a vessel 100 metres across.
Things are a bit better with actual atoms of antihydrogen of the sort just captured for the first time. These can still be contained electromagnetically despite the fact that they are not charged, as they have magnetic poles. Hangst says that one might theoretically get a milligram of the good news in this nega-hydrogen form into a mere 100-litre vessel - roughly the size of a keg of beer.
Unfortunately, as we now know from the ALPHA scientists' just-published paper, it's very difficult to get a magnetic grip on complete, neutrally charged anti-atoms - it can only be done even with the arse-kickingest magnets if they're moving very slowly - ie if they are extremely cold. According to Thompson, the antihydrogen must be chilled down to just a degree above absolute zero. Such temperatures are basically unachievable even for the superchill experts of CERN, well practiced in keeping the magnets of the Large Hadron Collider frozen down to single-figures Kelvin. Ultrahypercold containable antimatter atoms can only be obtained by evaporation, ie by throwing away most of the antimatter to cool the remainder.
As Hengst points out, if one were dealing with Dan Brown quantities of the stuff this would involve destroying one's lab many times over during production. Even if this snag could be somehow dealt with, the beerkeg antimatter bomb would still have to be wrapped in superconducting magnets and frozen down within a few degrees of absolute zero using liquid helium: in other words the associated apparatus would be the size of a large building. It would be more convenient to simply lug 50 tonnes of TNT along with you to the Vatican - or in the CERN physicists' case to their various national-government funding offices. (One notes the recent UK government decision not to cut science funding as part of the economic austerity package with interest in this context.)
Just to really give Dan Brown a good kicking, Hengst goes on to point out that even if the human race's top particle-furtling labs set themselves to producing antimatter as their main priority, making a single 50-tonnes-TNT-equivalent milligram of the stuff would be a time-consuming business: in fact it would take 300 billion years by his estimates. He concludes:
Back down to the sober reality here at CERN, we would be happy just to demonstrate trapping of antihydrogen in principle. This means initially trapping just a few anti-atoms ...
That at any rate has now been achieved: a great day for science, if not for Dan Brown (who cares) or the Starship Enterprise (more regrettable, but never mind).
Those with a subscription to hefty boffinry mag Nature can read the scientists' blockbusting paper Trapped antihydrogen here [3]. ®
*Headline to which the answer is no
Best line I've read this year!
It like trying to create man in a lab. Sooner or later.....
Create man in a lab? Never happen. Woman, however....it’s all about motivation, you see.
Ping
thx
Note: this topic is from 11/18/2010. Thanks markomalley.
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