How a pinhole-like eye can see shapes without a lens

A simple eye can form an image without a lens

In a simple cup-shaped eye, making the opening narrower improves the image more than making the cup deeper. If the opening becomes small enough, the eye can form a real image and recognize basic shapes even without a lens.

Ancient gears tracked the planets

Built around 80 BC, the Antikythera mechanism used a complex system of gears to calculate the movements of the planets. Its design challenged the old belief that such advanced gearing appeared only in the 16th century.

Air conditioning can add to warming

People use air conditioning to adapt to warmer conditions, but it uses energy and releases heat outdoors. Both can contribute to the warming it helps people cope with.

How a pinhole-like eye can see shapes without a lens

A simple eye can form an image without a lens

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