Family of Planets

there is the picture of Earth

Have you ever wanted to travel in space? In a way you already do, because you live on Earth, and Earth is a planet floating in space. There are other planets, too, a whole family of planets that scientists call our solar system.

there is the picture of the Sun
The Sun

The word “solar” means “having to do with the Sun.” The planets in our solar system all circle the Sun in paths called orbits. Planets that are closer to the Sun have shorter orbits. It doesn't take them as long to travel around the Sun. Planets farther from the Sun have longer orbits. It takes Earth about 365 days—one year—to travel around the Sun.

there is the picture of Jupiter

The planets are alike in another important way. They all spin, or rotate. It takes Earth 24 hours, or one day, to spin around one time. As Earth spins, the parts that face the Sun are lit up—it is daytime there. The parts that face away from the Sun are dark—it is nighttime.

there is the picture of Neptune

If you could visit the other planets, you would find some strange and surprising worlds. Some are dry and rocky, while others are balls of swirling gases with solid centers. Some planets are much hotter than Earth—so hot that nothing can live there. That's because they are so close to the Sun. Other planets are far away from the Sun. They are very, very cold—colder than any place on Earth.

there is the picture of Venus

Earth is just the right distance from the Sun—it is not too hot and not too cold. Earth has water to drink and air to breathe. Earth is the only planet in our solar system where plants and animals and people can live.

The Solar System

there is a picture of the solor system, with the planets ordered from the outside to the inside.
  1. Mercury
    Mercury is the closest planet to the Sun. It has the shortest orbit of all—it goes around the Sun in only 88 days.
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  2. Venus
    Venus is a scorching, fiery planet with thousands of volcanoes. Venus's air is poisonous to humans. Its sky is orange and gloomy and pierced with flashes of lightning.
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  3. Earth
    From space, Earth looks blue and white and green—full of life and a wonderful planet to call home.
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  4. Mars
    Mars is a desert planet covered with rocks and a fine, red dust. There are no oceans or signs of life, but there is ice, and scientists believe there may be water under the ground. Sometimes violent winds blow huge dust storms across the whole planet, giving the sky a pinkish glow.
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  5. Jupiter
    Jupiter is the largest planet, much larger than Earth. But it is mainly a big ball of gas. Jupiter spins faster than any other planet. This swift spinning whips up huge, swirling windstorms. There is a giant red spot on Jupiter that scientists think may be a hurricane that has been blowing for hundreds of years.
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  6. Saturn
    Saturn's colorful rings may look solid, but they are really just floating pieces of ice and rock and space dust. Astronauts can't land on Saturn because it doesn't have a solid surface. It is made up mostly of thick clouds of gas.
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  7. Uranus
    Some planets spin faster than Earth, some slower. Uranus is the only planet that seems to spin on its side! Scientists think that Uranus may have been hit by a large object that tilted it millions of years ago.
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  8. Neptune
    Neptune is a cold blue planet far from the Sun. It's so cold that icy crystals, not hot lava, spew out of the volcanoes on one of its moons.
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  9. Pluto
    Pluto is the smallest planet—a ball of ice and rock that is smaller even than our Moon. It takes faraway Pluto 248 years to go around the Sun!
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  10. And far beyond the planets are the stars!
Mercury Mercury Venus Venus Earth Earth mars mars jupiter jupiter saturn saturn uranus uranus neptune neptune pluto pluto



To send or force out.

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  1. How long does it take the Earth to orbit the Sun?
    [anno: It takes the Earth 365 days to orbit the Sun.]
  2. If it took the Earth 730 days to orbit the Sun, how would this change the seasons? How would life be different than it is now? Write a few sentences describing how life would be different if it took the Earth 730 days to orbit the Sun.
    [anno: Answers will vary but could include that the seasons would all be twice as long. People would have to grow and store more food in the summer to make it through the winter.]