Venus is often called Earth’s “sister planet” because it’s similar in size, mass, and composition. But despite these similarities, Venus is a world of extreme and hostile conditions. It is the second planet from the Sun and the hottest planet in our solar system—even hotter than Mercury, which is closer to the Sun. This intense heat, reaching up to 475°C (900°F), is caused by Venus's thick atmosphere, made mostly of carbon dioxide, which traps heat in a runaway greenhouse effect. The surface is hot enough to melt lead, and the sky is filled with thick yellow clouds of toxic sulfuric acid.

Venus also has a very slow and strange rotation. A single day on Venus (one full rotation) is longer than its year—it takes about 243 Earth days to rotate once, but only 225 days to orbit the Sun. Even more bizarre, Venus rotates in the opposite direction of most other planets, so if you could stand on its surface, the Sun would appear to rise in the west and set in the east. Because of its dense atmosphere and high pressure—over 90 times that of Earth—landing a spacecraft on Venus is incredibly difficult, and only a few missions have survived for a short time on its surface.

Despite its harsh conditions, Venus is a key focus for scientists because studying its climate helps us understand climate change and atmospheric evolution on Earth. It also raises fascinating questions about whether Venus might have once had oceans or even life long ago. Covered in volcanoes, mountains, and vast plains, Venus remains one of the most mysterious and captivating planets in the solar system.