- What positively charged particle did Dirac's equation imply, and how did Carl Anderson confirm it experimentally in 1932?
- Why did Dirac initially try to interpret his equation's extra solution as the proton instead of a new particle?
Antimatter
Particles that are mirror opposites of ordinary matter.
- What surplus solutions in Dirac's 1928 equation led him to predict a mirror-electron with opposite charge?
- How did the curvature of a cloud chamber track reveal that Anderson had found a positively charged, lightweight particle?
- Why did Anderson initially suspect his own instrument was in error before confirming the positron was real?
- Where does the positron show up in medicine today, decades after Dirac's theoretical prediction?
- Why did Dirac's relativistic equation require the existence of a positively charged electron?
- How did Carl Anderson confirm the positron experimentally in 1932?
- Why did aluminium, boron, and magnesium keep emitting positrons even after the polonium source was removed?
- How did Carl Anderson recognize the positron from the way its track curved in a cloud chamber?
- What had Paul Dirac predicted in 1928 that Anderson's photograph confirmed eight years later?
- Why did many physicists hope Dirac's prediction of antimatter was wrong?
- What earlier discovery had the cloud chamber already enabled before Blackett's improvement?
- What feature of Dirac's equation implied the existence of antimatter particles like the antiproton?
- How did Segrè, Chamberlain, Wiegand, and Ypsilantis distinguish rare antiprotons from the far more common pions in the Bevatron's output?
- Why does the near-total absence of antimatter in today's universe remain an unsolved puzzle given that antiprotons can be created on demand?
- What did Dirac's equation for the electron predict about a mirror-image particle, decades before it was found?
- How did Segrè and Chamberlain use the Bevatron to distinguish antiprotons from the flood of ordinary collision debris?
- Why is it considered a needle-in-a-haystack problem to detect an antiproton when the needle annihilates on contact with the haystack?
- Why does the universe appear to be made almost entirely of matter rather than an equal mix of matter and antimatter?
- Why does the small CP violation found in 1964 help explain why matter outnumbers antimatter in the universe?
- Why does CP violation help explain why the universe contains matter at all instead of nothing but photons?
- How does stochastic cooling let physicists corral a chaotic beam of antiprotons without touching any individual particle?
- Why was accumulating antiprotons in useful quantities considered nearly impossible before van der Meer's technique?
- What made Dirac's 1928 relativistic wave equation for the electron more symmetrical than physics seemed to require?
- How did Dirac's equation predict the existence of a particle with the electron's mass but opposite charge?
- How many years passed between Dirac's mathematical prediction and Carl Anderson's experimental discovery of the positron?
- Why would the universe contain nothing but radiation if matter and antimatter had been produced in perfectly equal amounts?