What shape are subatomic particles?

Asked by: Mark Buckmaster, Leicester

We usually think of electrons, protons and the like as being perfectly spherical, like tiny marbles. Yet while this seems to be pretty accurate in the case of electrons, studies of protons have revealed that they are constantly changing shape. By firing particles at them and analysing the resulting trajectories, physicists have found that the shape of protons is affected by the speed of even smaller particles within them called quarks, three of which are jostling around inside each one.

Here are four shapes of proton:

• Peanut: produced by the fastest quarks, spinning in the same direction as the proton
• Rugby ball: produced by quarks that are moving slower than in the peanut and bagel shapes
• Bagel: produced by the fastest quarks, spinning in the opposite direction from the proton
• Sphere: produced by the slowest quarks

Read more:

• Are atoms expanding as the Universe expands?
• If atoms are mostly empty space, why is matter not transparent?

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