Follow your curiosity

What discovery has been shared with you?

FACTREE gives you something interesting to discover every day — and something worth talking about together.

Start with one fact. Explore it, go deeper, then follow whichever branch catches your imagination.

Choose subjects for a surprise

Exploring any topic

Begin your discovery

Your next discovery is one click away.

Choose one or more subjects above, or leave Any Topic selected and let curiosity decide.

Physics

Spontaneous Emission of Radiation

Quick fact

An atom in an excited state typically stays there for only about 10⁻⁸ seconds before spontaneously emitting a photon—a blink nearly 100 million times faster than a camera flash.

Why this is interesting

You flip a switch and light floods the room—but how does an atom decide to 'glow' on its own, without any push? That mysterious, automatic release of light is called spontaneous emission.