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Mars is a cold desert world. It is half the size of Earth. 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 of carbon dioxide, nitrogen, and argon.

There are signs of ancient floods on Mars, but now water mostly exists in icy dirt and thin clouds. On some Martian hillsides, there is evidence of liquid salty water in the ground.

Scientists want to know if Mars may have had living things in the past. They also want to know if Mars could support life now or in the future.

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Mars is a terrestrial planet. It is small and rocky.

Mars has a thin atmosphere.

Mars has an active atmosphere, but the surface of the planet is not active. Its volcanoes are dead.

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There are four rovers.

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The Mars Rovers: Sojourner :: NASA Space Place

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Learn more about the first rover to land on Mars!

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Draw one of the Mars Rovers down below.

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Read the information on Mercury and tell me 3 facts you learned.

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Mercury is the smallest planet in our solar system. It's just a little bigger than Earth's moon. It is the closest planet to the sun, but it's actually not the hottest. Venus is hotter.

Along with Venus, Earth, and Mars, Mercury is one of the rocky planets. It has a solid surface that is covered with craters. It has no atmosphere, and it doesn't have any moons. Mercury likes to keep things simple.

This small planet spins around slowly compared to Earth, so one day lasts a long time. Mercury takes 59 Earth days to make one full rotation. A year on Mercury goes by fast. Because it's the closest planet to the sun, it doesn't take very long to go all the way around. It completes one revolution around the sun in just 88 Earth days. If you lived on Mercury, you'd have a birthday every three months!

A day on Mercury is not like a day here on Earth. For us, the sun rises and sets each and every day. Because Mercury has a slow spin and short year, it takes a long time for the sun to rise and set there. Mercury only has one sunrise every 180 Earth days! Isn't that weird?

Structure and Surface

Mercury is the smallest planet in our solar system.

Mercury is a terrestrial planet. It is small and rocky.

Mercury doesn't really have an atmosphere.

Time on Mercury

A day on Mercury lasts 59 Earth days.

A year on Mercury lasts 88 Earth days.

Mercury's Neighbors

Mercury does not have any moons.

Mercury is the closest planet to the sun.

Venus is Mercury's neighboring planet.

Quick History

Mercury has been known since ancient times because it can be seen without advanced telescopes.

Mercury has been visited by two spacecraft: Mariner 10 and MESSENGER.

What does Mercury look like?

For more information visit:
NASA Solar System Exploration