Picometre

The picometre (or picometer in American spelling) is a very small unit of length. It equals 10^-12 metres, which is one trillionth of a metre. Imagine a metre — about the length of a guitar — and splitting it into one trillion equal parts. Each tiny part is one picometre.

Picometres help us measure extremely small things, like the distances between atoms in molecules. They are part of the International System of Units, the same system that gives us metres, grams, and litres. This unit helps scientists study the tiniest parts of matter.

The picometre is related to other small units of length. It is one thousand femtometres, one thousandth of a nanometre, and one millionth of a micrometre. These tiny measurements help us understand the world at its smallest levels.

Use

The picometre is a very small unit of length. We use it in particle physics, quantum physics, chemistry, and acoustics. Atoms, the tiny building blocks of matter, are about 62 to 520 picometres wide. For example, the distance between two carbon atoms in a single bond is 154 picometres. Even smaller units can describe the tiniest particles.

The planned Laser Interferometer Space Antenna (LISA) probe will launch in 2034 to detect gravitational waves. It will measure changes in distance with a precision of 20 picometres over a distance of 2.5 gigametres.