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Astronomy: Earth Moon System

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The Earth

How the Earth Works

Even though it's tiny compared to the rest of the universe, the Earth is enormous, and it's extremely complex. Systems powered by the sun are able to sustain the various life forms living on Earth.

Earth Explained

Earth is the third planet from the sun, and the fifth largest. Learn more about our home planet.

How much does planet Earth weigh?

The weight of planet Earth can be figured out by measuring the gravitational attraction the planet has for surrounding objects. So what, exactly, is the weight of the Earth if you were to put it on a scale. Find out in this article.

What if there was no gravity on Earth?

Have you ever wondered what would happen if we were able to flip a switch and turn the Earth's gravity off for a day? The end result of what would happen may surprise you.

What is the Chandler wobble?

The Chandler wobble is the change in the spin of the earth on its axis. Think of the wobble you see in a toy top when it first starts spinning or slows down. Its "poles" do not spin in a perfectly straight line.

Earth's Perfect Orbit (Video)

Watch this animated video from NASA explaining why the Earth's orbit is perfectly situated around the sun so that the Earth is not too hot or too cold. This video teaches kids what could happen if the Earth got too close or too far away from the sun.

How big is the Earth? (Video)

How big is the Earth? Find out in this HowStuffWorks video!...

The Earth: Crash Course Astronomy #11

The Moon: Crash Course Astronomy #12

Moon Phases: Crash Course Astronomy #4