Yes, you have guessed it, I am reading the second first book by Mr Boring Author Name Award 2005 - Dan Brown.
"Angels and Demons" is the precursor to "The Da Vinci Code" (See my post).
It is a story that starts where I have just given up a job - CERN (Centre European pour la Recherche Nucleaire), and central to the plot is an understanding of what antimatter is. Everything he says about CERN is correct, but he needs to brush up on his Physics a little!
Of course I know what poetic license is, but all the same, allow me to enlighten you a little as to the difference between Dan Brown and physics.
Anti-Matter? Physics. Recent production? No, CERN have been doing it for 20 years.
LHC? Yes, it exists, I have been there. Diameter 8 km? Yes.
Making a miniature Big Bang in the LHC? No. Making matter from nothing? No. Mr Brown conveniently forgets about all the energy needed to send the particles around the ring.
Matter-antimatter energy conversion 100% efficient? Oh yes!
Here's the rub - Bottles of antimatter? ABSOLUTELY NOT!
Many reasons:
1) Antiprotons need a true vacuum to be stable. Even intergalactic space is not even a true vacuum (see my space Sickness Pills post), and certainly a true vacuum on earth is impossible, and certainly if one is created, minute leaks will soon cause annihilation.
2) Stable magnetic bottle? Well, we are still working on that one, and it is not quite perfected yet.
3) The Bottle in the story has a quarter gram of antiprotons. Antiprotons have a negative charge. All of them. To overcome the negative electrostatic repulsion, one would have to have GI-normous magnetic fields involving magnets the size of rooms.
The REAL stuff that CERN does with antiprotons is exactly as Mr Brown explains - we throw protons round the LHC and using the same magnets, hurl antiprotons the other way. It works because they have the same mass.
At certain points in the ring we collide them, and collect the debris using huge detectors the size of office buildings.
What happens when a proton (travelling at 99% the speed of light) collides with an antiproton (travelling with the same speed in the opposite direction)? Annihilation, of course! But in this case, not only is the energy from the particles' mass available (939 MeV x 2 via e=mc2), but also the relativistic kinetic energy x 2.
Result; Two gamma rays, travelling in opposite directions (2 because both energy AND momentum need to be conserved). These gamma rays have so much energy that the reverse now happens.
Using E=mc2 many other particles are simply created (yes, created out of thin air, one particle, one antiparticle)
Why does this happen? It is exactly like a spark of electricity or lightning. In either, there is so much charge, that despite being an insulator, the air breaks down and carries a current.
Same with these two gamma rays, and they both become two "jets" of particles. These are called two-jet events, and were used to discover the intermediate vector boson, predicted in 1974, the carrier of the weak force, the Z-0. This was detected in the early eighties.
Sometimes, though, but not very often, we see a "3-jet event". That is, the two gamma rays become three jets instead of two. This is a purely gluon event........
For more, just watch this space.....
Wednesday, August 17, 2005
"Angels and Demons" - Reality Check!
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5 comments:
Space is never empty space, simple as that. Average density of space is about a proton per liter.
This proton would only annihilate one antiproton, though.
But that same proton, if you read my "Space sickness" post, would fry passengers abourd any ship that goes fast enough.
Nerd, I do not think empty space can be created. That was the basis for the Steady-State theory put forward by Hoyle et al to explain the expansion of the Universe. Even if you did create nothing, how would you know it was there?
Nerd: All my "interesting ideas" as you call them come from "Physical Laws". When I have my own ideas, or in some cases, easy ways to explain things (such as "electrical resistance" or "time travel"), I say so.
Others, such as "magnetic bottles to contain antimatter are impossible" rely on physical law.
Also, when I put forward an opinion (rarely on this blog), I say so. Many people in the science rooms who think they know science state their opinions of aspects of physics as fact. It takes a true scientist to know the difference.
Nerd: Well, one cannot be master of all subjects, but thanks for the professor compliment, anyway.
Well, I most of all think about nuclear structure. but studying all this physics leads me to all sorts of ruminations, it is just that this is the first time I have even a remote chance of getting these things down, let alone give other people a chance to see them.
As for microgravity, it depends what you mean. You can certainly make a good guess at the mass of a mountain by hanging a bob near it and measuring how far from the vertical it strays.
As fior "creating" gravity. that is an entiely different matter. I suppose you could say that gravity has been created in my Angels and Demons post, as matter has been created when those particles collide, but it such a miniscule amount, it is a far cry even from "micro-gravity". Other than that, there is no other way to create even micro-gravity.
Lawny: "anti-gravity"? Not necessarily.The photon is the carrierof the electromagnetic field. It, too, has an antiparticle, but do we have an antielectromagnetic field? NO!
This is because the photon is its own antiparticle,and it is possible that the gravity carrier has the same property (and I suspect it does, being a boson)
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