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PHVSICS OF THE IMPOSSIBLE
in-time solutions: they represented the motion of antimatter. If he had
been an older physicist, Feynman might have thrown this solution out
the window. But being a lowly graduate student, he decided to pursue
his curiosity further.
As he continued to delve into this conundrum the young Feynman
noticed something even stranger. Normally if an electron and an antielectron collide, they annihilate one another and create a gamma ray.
He drew this on a sheet of paper: two objects bumping into each other,
turning into a burst of energy.
But then if you reversed the charge of the antielectron, it became
an ordinary electron going backward in time. You could then rewrite
the same diagram with the arrow of time reversed. It now appeared as
if the electron went forward in time, then suddenly decided to reverse
direction. The electron did a U-turn in time and was now going backward in time, releasing a burst of energy in the process. In other
words, it's the same electron. The electron-antielectron annihilation
process was just the same electron deciding to go backward in time!
So Feynman revealed the true secret of antimatter: it's just ordinary
matter going backward in time. This simple observation immediately
explained the puzzle that all particles have antiparticle partners: it's
because all particles can travel backward in time, and hence masquerade as antimatter. (This interpretation is equivalent to the "Dirac sea,"
mentioned earlier, but it is simpler, and it is the explanation currently
accepted today.)
Now let's say we have a lump of antimatter and it collides with ordinary matter, creating a huge explosion. There are now trillions of
electrons and trillions of antielectrons being annihilated. But if we reversed the direction of the arrow for the antielectron, turning it into an
electron going backward in time, this would mean that the same electron went zigzagging backward and forward trillions of times.
There was a further curious result: there must be just one electron
in the lump of matter. The same electron went whizzing back and
forth, zigzagging in time. Each time it did a U-turn in time it became
antimatter. But if it did another U-turn in time then it turned into another electron.
PHVSICS OF THE IMPOSSIBLE
in-time solutions: they represented the motion of antimatter. If he had
been an older physicist, Feynman might have thrown this solution out
the window. But being a lowly graduate student, he decided to pursue
his curiosity further.
As he continued to delve into this conundrum the young Feynman
noticed something even stranger. Normally if an electron and an antielectron collide, they annihilate one another and create a gamma ray.
He drew this on a sheet of paper: two objects bumping into each other,
turning into a burst of energy.
But then if you reversed the charge of the antielectron, it became
an ordinary electron going backward in time. You could then rewrite
the same diagram with the arrow of time reversed. It now appeared as
if the electron went forward in time, then suddenly decided to reverse
direction. The electron did a U-turn in time and was now going backward in time, releasing a burst of energy in the process. In other
words, it's the same electron. The electron-antielectron annihilation
process was just the same electron deciding to go backward in time!
So Feynman revealed the true secret of antimatter: it's just ordinary
matter going backward in time. This simple observation immediately
explained the puzzle that all particles have antiparticle partners: it's
because all particles can travel backward in time, and hence masquerade as antimatter. (This interpretation is equivalent to the "Dirac sea,"
mentioned earlier, but it is simpler, and it is the explanation currently
accepted today.)
Now let's say we have a lump of antimatter and it collides with ordinary matter, creating a huge explosion. There are now trillions of
electrons and trillions of antielectrons being annihilated. But if we reversed the direction of the arrow for the antielectron, turning it into an
electron going backward in time, this would mean that the same electron went zigzagging backward and forward trillions of times.
There was a further curious result: there must be just one electron
in the lump of matter. The same electron went whizzing back and
forth, zigzagging in time. Each time it did a U-turn in time it became
antimatter. But if it did another U-turn in time then it turned into another electron.