Venus: Why Earth's Similar-Sized Neighbor Became So Extreme

Why Venus is similar to Earth in size yet has crushing pressure, intense heat, and a very different climate history.

Earth's near twin in size

Venus is close to Earth in diameter and mass, which is why it is sometimes called Earth's sister planet. But the surface conditions are dramatically different.

A thick atmosphere

Venus has a dense atmosphere dominated by carbon dioxide. Thick clouds hide the surface from ordinary visible-light observations and contribute to powerful greenhouse warming.

The runaway greenhouse effect

Solar energy reaches the surface and atmosphere, but heat is trapped very efficiently. This has made Venus the hottest planet in our Solar System at the surface.

What Venus can teach us

Studying Venus helps scientists explore how planetary climates change. Comparing Earth and Venus gives researchers two very different outcomes for rocky planets of similar size.

Renewed interest

New mission concepts and observations aim to study Venusian geology, atmosphere and climate history. These studies may clarify whether ancient Venus was once more temperate.