How dragonfish hunt with red light

Dragonfish hunt with red light most deep-sea animals cannot see

Some deep-sea dragonfish make red light and can see it. Most other animals in the deep ocean cannot because natural red light disappears near the surface. The fish can therefore light up red prey without making the scene visible to many nearby animals.

Ancient Egyptians used iron from meteorites thousands of years before the Iron Age

≈3200 BC

Nine iron-and-nickel beads found in Egyptian graves date to about 3200 BC, thousands of years before the Iron Age. The metal probably came from meteorites and was shaped by repeated heating and hammering. People could work iron long before they learned to make it from ore on a large scale.

Averaging many opinions does not remove a shared bias

Combining many people's estimates can cancel random mistakes. But if most people make the same kind of mistake in the same direction, averaging their answers keeps that shared bias.

Like this? There’s a whole feed of it. Replace empty scrolling with things worth knowing.

Download Hence for free

How dragonfish hunt with red light

Dragonfish hunt with red light most deep-sea animals cannot see

Keep exploring