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反物质的五大谜团
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1、反物质在哪里？
Standard theory predicts that the big bang should have created as much antimatter as matter – so why does the universe seem to be made entirely of matter?
2、反物质如何制造？
Researchers at CERN are trying to make antimatter in useful quantities. But it's hard to pin down a substance that vanishes as soon as it touches anything.
3、反物质会象“牛顿苹果”一样掉落吗？
Gravity works the same way on all matter – but what about antimatter? If it behaves differently, it could overturn our understanding of physics.
4、我们能否缔造一个反物质世界？
Physicists are finding it difficult to tame antihydrogen, the simplest possible anti-atom. Is there any hope of making more complex anti-atoms?
5、反物质可否用来制造终极炸弹？
The idea that humanity might one day harness antimatter for destructive purposes has a ghastly fascination.
Antimatter: A Briefing
- Every particle has an antiparticle with the same mass but the opposite electric charge. The proton has the negatively charged antiproton; the electron has the positively charged anti-electron, or positron.
- Neutral particles can have antiparticles, too. The neutron might have no charge, but quarks - the smaller particles that make it up - do. Turn these quarks into antiquarks by flipping their charges, and you've made an antineutron.
- The possibility of antimatter first surfaced in equations formulated by British theoretical physicist Paul Dirac in 1928 - four years before American experimenter Carl Anderson found positrons in cosmic rays.
- Notoriously, matter and antimatter destroy each other, or annihilate, whenever they come into contact. An electron and a positron mutually destruct in a puff of light consisting of two photons sent out in precisely opposite directions, each with an energy corresponding exactly to the mass of the electron (and positron).
Bibliography
- Antimatter by Frank Close (Oxford University Press, 2009)
https://blog.sciencenet.cn/blog-52206-294693.html
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