Mars – the fourth planet from the Sun – is a dusty, cold, desert world with a very thin atmosphere. This dynamic planet has seasons, polar ice caps, extinct volcanoes, canyons and weather.

It’s dry, rocky, and bitter cold. The fourth planet from the Sun, Mars, is one of Earth's two closest planetary neighbors (Venus is the other). Mars is one of the easiest planets to spot in the night sky — it looks like a bright red point of light.

Mars is the fourth planet from the Sun – a dusty, cold, desert world with a very thin atmosphere. Mars is also a dynamic planet with seasons, polar ice caps, canyons, extinct volcanoes, and evidence that it was even more active in the past.

Mars is sometimes called the Red Planet. It's red because of rusty iron in the ground. Like Earth, Mars has seasons, polar ice caps, volcanoes, canyons, and weather. It has a very thin atmosphere made mostly of carbon dioxide, nitrogen, and argon. People would not be able to breathe the air on Mars.

Mars has a thin, cold, carbon dioxide atmosphere. Its air pressure is less than 1% that of Earth’s. However, Mars has thick ice caps at both poles, similar to Earth. The surface of Mars is a cold, dry desert. But during its early history, it had rivers and lakes—and perhaps even a northern ocean.