Brian Clegg

Here traditional numbers become clumsy; a typical adult is made up of around 7,000,000,000,000,000,000,000,000,000 atoms. It’s much easier to say 7 × 1027, simply meaning 7 with 27 zeroes after it. That’s more than a billion atoms for every second the universe is thought to have existed

Why does the mirror switch around left and right, but leave top and bottom the same? Why does it treat the two directions differently

There are various possibilities as to why it made evolutionary sense to lose the majority of our hair. It might have been due to the need to sweat more as our ancestors moved from the forest to the savannah

The most likely pre-humans to survive were those with a natural tendency to cooperate. Our ancestors began to live in larger groups, giving them the ability to take on a predator and win, where a small band would be torn to pieces

If you think about an electron whizzing around in an atom like a miniature planet, it would always be changing direction, always accelerating. And that means it would lose energy as a burst of light and would plunge into the nucleus in a tiny fraction of a second. Every atom in the universe would instantly self-destruct

Physicists have produced something called the ‘standard model’, which describes everything we know in existence being based on around nineteen different fundamental particles. Twelve of these are matter particles, like quarks and electrons, plus some more obscure variants found in nuclear reactions and collider experiments. Another five are special particles that carry forces. So, for instance, there’s the photon which is both a particle of light and carries electromagnetic force from place to place.

A kilogram of antimatter, annihilating with an equivalent amount of matter, generates the equivalent of a typical power station running for around twelve years

That temperature, unreachable in practice because quantum particles can never entirely stop, is absolute zero

A condensate is a state of matter where the particles that make it up lose their individuality. This results in strange behaviours like superfluidity, where the substance has absolutely no resistance to movement

There are so many atoms in a person (7 × 1027) that after a while, many of them will be recycled in other human beings. Your body contains atoms from kings and queens, noble warriors and court jesters