dietz@SLB-DOLL.CSNET (Paul Dietz) (03/14/86)
Storing frozen antihydrogen: surround the antihydrogen ball with a spherical shell cooled to near 0 K. A gas atom emitted from the wall will travel in a random direction until it strikes another wall or the pellet. The chance it hits the pellet instead of another wall can be reduced arbitrarily far by increasing the radius of the shell. If the mechanism by which gas atoms are liberated is radiation bombardment from the antimatter then for sufficiently large shell radii the chain reaction dies out. By the way, an explosion with the force of "trillions of H bombs" would require the annihillation of tens of millions of tons of antimatter. Might we make it in gram quantities first? Getting antihydrogen: we can currently make antiprotons at miserably low efficiency (~10**-6). Techniques have been developed and tested for cooling the antiprotons (reducing their velocity dispersion) and for decelerating them. Positrons are easy to produce by pair production. Recently techniques have been developed for slowing atoms by interactions with laser light; sodium atoms have been slowed to a few meters/second by this mechanism. The same techniques should work with antihydrogen. The atoms could then be plated out (slowly!) on antihydrogen pellets. Using antimatter: Even at current prices, antimatter might be useful for triggering "clean" fusion weapons. Reduce the cost by two or three orders of magnitude and it could be useful for rocket fuel. It would be used to heat much larger quantities of (say) hydrogen. To guide antihydrogen into a rocket engine would be tricky but not obviously impossible. A small quantity would be vaporized by laser; the resulting gas ionized with ultraviolet light and the resulting plasma guided by magnetic fields. Alternately, charged antihydrogen pellets might be manipulated intact by electrostatic fields. Antimatter and fusion are both terribly speculative. I personally like beam powered spacecraft; they seem much more practical.
KFL@MC.LCS.MIT.EDU ("Keith F. Lynch") (03/16/86)
From: Paul Dietz <dietz%slb-doll.csnet@CSNET-RELAY.ARPA>
By the way, an explosion with
the force of "trillions of H bombs" would require the annihillation
of tens of millions of tons of antimatter. Might we make it in
gram quantities first?
Not if you want to take a reasonable mass (1000 people plus all
resources needed to start a colony) to the stars in a reasonable time
(less than a century).
Even at current prices, antimatter might be useful
for triggering "clean" fusion weapons.
Just what we need. (Talk about hair trigger!)
...KeithST401385@BROWNVM.BITNET (03/24/86)
In an article KFL@MC.LCS.MIT.EDU ("Keith F. Lynch") writes: > > One theory says that antimatter is identical to matter only switched >left to right... No theory I'm familiar with says that. The operation of changing a particle into its antiparticle is known as charge conjugation (ie., reversal), refered to as the operator "C". There is a general theorem that Charge, Parity (left/right reversal), and Time conjugation together (CPT) will return a particle to an indistinguishable state. (indistinguishable to itself: That is, if a system is CPT conjugated, there is no way to discover it within the system.) The tough part is going to be reversing time... > According to relativity, space is curved. The curvature can be >changed by rearranging masses. So, while I see no way to put a half >twist into space, it is by no means theoretically impossible or >unthinkable. Unfortunately, a continuous parity transformation would requite the TOPOLOGY of space to be changed. Just moving masses around may change the curvature, but the topology remains the same. (eg., you can distort a pancake into a bowl, but not into a coffee cup. Or a Moebus strip.) (however, space which includes singularities (eg., black holes) already has a distorted topology). --Geoffrey A. Landis, Brown University Reply to: ST401385%BROWNVM.BITNET@WISCVM.ARPA