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Terrestrial planets

Encyclopedia entries

True-color image of Mars Entry

Mars: The Red Planet Explained

Mars is the Red Planet: thin CO2 air, giant volcanoes, deep canyons, polar ice, two moons, and strong evidence of ancient water.

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The Blue Marble photograph of Earth from Apollo 17 Entry

Earth: Our Living Home Planet

Earth is the third planet and only known living world: oceans, oxygen-rich air, magnetic field, plate tectonics, and one large Moon.

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Real-color image of Venus cloud cover Entry

Venus: Earth’s Hot Twin Planet

Venus is Earth’s size twin and the hottest planet: thick CO2 air, acid clouds, crushing pressure, and a slow backward spin.

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True-color view of planet Mercury showing a gray cratered globe Entry

Mercury: The Closest Planet to the Sun

Mercury is the closest planet to the Sun: extreme heat and cold, a huge iron core, polar ice, and a day longer…

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