✦ Nature & animals · Discovery of the hour

Why does an octopus have three hearts?

Three pumps help an octopus move oxygen around a body built for life underwater.

A new topic is featured each hour. Every article remains available in the archive.

Find your curiosity

Choose a world to explore

Each discovery has its own page, so you can read, revisit and share it whenever you like.

Handpicked reading

Short, original explanations with context, caveats and links to further reading.

The shape begins inside the intestine, not when the droppings land on the ground.

The arrangement of water molecules changes when the liquid becomes an ordinary ice crystal.

The familiar arch is a perspective effect created by sunlight and water droplets.

The discs between your spinal bones slowly change height throughout the day.

Venus spins slowly while completing its orbit around the Sun comparatively quickly.

An illustrated historical book contains writing that scholars cannot confidently read.