Understanding the Inner Planets — Passage and Quiz
Understanding the Inner Planets
The inner planets of our solar system are Mercury, Venus, Earth, and Mars. These planets are closest to the Sun and are known as terrestrial planets because they have solid, rocky surfaces.
Mercury is the smallest inner planet and is covered with craters. It has extreme temperatures, being very hot during the day and freezing at night due to its thin atmosphere. Venus, the hottest planet, has thick clouds that trap heat. It has mountains and volcanoes on its surface. Earth is unique because it supports life. It has water, air, land, and a variety of climates and ecosystems. Mars, known as the Red Planet, has a reddish appearance due to iron oxide on its surface. It features the tallest volcano and a vast canyon.
These planets are made mostly of rock and metal, unlike the outer planets, which are composed of gasses and ice. The inner planets help scientists learn more about planetary formation and the conditions necessary for life.
Quiz
1. Which planet is the smallest inner planet?
2. What makes Earth unique among the inner planets?
3. Why is Mars known as the Red Planet?
4. What are the inner planets mostly made of?
Common core standards covered
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