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Antimatter Propulsion
er333 writes "A group at Penn State is building prototypes of antimatter storage for space applications, and makes a good case that with the amount of antimatter that will be produced in a few years, "omniplanetary" missions will become practical, including manned missions to Jupiter.
They have some images describing possible missions and a concept craft design called the ICAN II."
It's fairly clear why the second bomb was dropped, although these reasons don't stand up brilliantly in hindsight.
The Japanese civilian leadership wanted to surrender after the first bomb was dropped, but the more powerful military leadership refused. One of the reasons for this was that news didn't get from Hiroshima to Tokyo for at least a day after the first bomb was dropped, something that the american leadership failed to predict. The americans were therefore surprised that the Japanese didn't sue for peace immediately.
Another reason for dropping the second bomb was that Stalin declared war on Japan just after the Hiroshima bombing, and immediately attacked Japanese positions on mainland Asia. The Americans didn't want Stalin to win too much against Japan (the mindset of the cold war had already started at this point), so it was deemed necessary to get the Japanese to surrender immediately.
Throughout this you have to remember that six months earlier, the allies had won a war against Germany, with German divisions generally surrendering or retreating after 30% casualties. When the Americans invaded Guam and Saipan, the Japanese troops didn't surrender at all, and after ~90% losses, forced Japanese civilians on the islands to commit suicide rather than be captured, before committing suicide themselves. This event appeared in the American press, and the feeling was that if the Japanese defended a captured territory that strongly, then there was no chance of invading Japan.
A blockade on Japan would have hurt even more civilians, as food and fuel would have been cut off. Japan gets very cold in winter, and civilian deaths from a blockade would have been much higher than from the two atom bombs.
Most of this view is explained in "The Making of the Atom Bomb" by Richard Rhodes, which I admit takes an American viewpoint for most of the book, but I would say is fair at explaining the reasons the Americans had for dropping the two bombs.
Penning trap + diagram
Nope. I think you may have misunderstood what your professor was saying. Total annihilation of 1 kilogram of matter will produce about 8.9E16 Joules of energy (E=mc^2). There are about 4.2E12 Joules in a kiloton of TNT equivalent, so this is roughly equivalent to a 21000 kiloton, or 21 megaton nuclear bomb. A big bang, certainly, but not anywhere near enough to destroy a whole continent. Many nukes of that size (and larger.... 50 MT and up) have been detonated, and as far as I know all the major continents are still here. :-)
Of course, the kilo of antimatter will also wipe out a kilo of normal matter, doubling the yield, but that's still not enough to vaporize a continent.
... that currently, it's really hard to produce - as the article says there are less than 10 nanograms currently produced each year, and the projected yield from Fermilab's new equipment would be no more than 140ng or so. And this requires huge particle accelerators costing billions of dollars.
And even when you've got these going, the cost to run them is prohibitive. And then there's the problem of keeping them stored for long periods at a time and transporting them. Despite a 100% matter to energy conversion rate antimatter has got to be one of the most inefficient fuel sources out there when you look at the entire picture! We'd be conserving resources by making coal-powered spaceships...
So Bush is probably going to love this :)
And an increased capacity to produce antimatter, while way out of our reach at the moment, brings new problems with it. After all, matter-antimatter reactions are far more efficient than even fusion reactions at converting matter to energy, and the military uses for this are obvious, especially to anyone who has read the Night's Dawn trilogy. It wouldn't suprise me if this sort of thing is being investigated somewhere as a speculative new military tool.
Hopefully, I'm just being paranoid. But given the military's obsession with technological superiority, I doubt it...
It blows my mind that we're actually discussing putting a man (or woman) on Mars using an anti-matter propelled craft that will be assembled and launched from an orbiting space station. The fact that we're capable of such a thing absolutely amazes me. It's even more amazing when you realize that space exploration is less than fifty years old.
To put things in perspective, my father remembers Sputnik. My grandfather got around town in a horse and buggy. I wonder what my kids will get to see...
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