2. THE EARTH, SUN AND MOON

How do the Sun, Earth, and Moon move?

We’re always on the move! Even when you’re standing still, you’re moving! You are moving because the Earth and everything in our solar system is constantly moving.

Our solar system includes the Sun, nine planets and their Moons, comets and asteroids. These objects are sometimes called celestial bodies, and they are constantly moving, too.

At the center of it all is the Sun. It takes the Sun 25 days to spin, or rotate, completely around.

The Earth, which is the third planet from the Sun, takes 24 hours to rotate. This is what causes day and night. As the Earth rotates, it also moves, or revolves, around the Sun.

The Earth’s path around the Sun is called its orbit. It takes the Earth one year, or 365 1/4 days, to completely orbit the Sun.

As the Earth orbits the Sun, the Moon orbits the Earth. The Moon’s orbit lasts 27 1/2 days, but because the Earth keeps moving, it takes the Moon two extra days, 29 1/2, to come back to the same place in our sky.

The greatest picture ever taken of the Moon and the Earth: Apollo 8, the first manned mission to the moon, entered lunar orbit on Christmas Eve, Dec. 24, 1968.

1) Earth is the third planet from the sun in our solar system. Its name comes from the the old English and Germanic words meaning ‘the ground’.

2) Our amazing planet has been around for quite some time. By researching our planet’s rocks, scientists have calculated the Earth to be around 4.5 billion years old!

3) Like all the planets, Earth orbits (travels around) around the sun. And it does so at some serious speed –– around 30 kilometres per second, in fact! It takes 365 days (one year) for the Earth to complete one full orbit.

4) Have you ever wondered why we have different seasons? We’ll tell you –– it’s because the Earth is tilted 23.4 degrees on its ‘axis’, an imaginary line straight through the middle of the planet form the North Pole to the South Pole. This means that different parts of the globe are tilted towards the sun at different times of the year (or at different times during its orbit).

5) Not only does Earth zoom through space, it also spins on its axis. The result? We have daytime and nighttime! As the planet rotates, the side facing the sun receives daylight and the the other is in darkness.

6) People often think of Earth as a gigantic sphere. But, in fact, its shape is more like a squished ball that bulges out at the equator –– an imaginary line around the middle of the planet, exactly between the North Pole and the South Pole.

7) This ‘bulge’ is caused by the Earth’s spin and the effect of ‘gravity‘. Gravity is an invisible force that attracts objects towards each other. It’s this force that pulls things towards the Earth and stops us floating off into space!

8) The Earth’s diameter (distance straight through the middle) measures a huge 12,800 kilometres, making it the fifth largest planet in the solar system. Jupiter, Saturn, Uranus and Neptune are even bigger!

9) Earth is the only planet in our solar system known to support life. This is because it has two very important things that living creatures need to survive –– lots of oxygen and lots of water! Its distance from the sun means it’s not too hot and not too cold for creatures to live on, too.

10) Earth’s ‘atmosphere’ is also hugely important for sustaining life. The atmosphere is a huge blanket of gases – mostly oxygen and nitrogen – wrapped around Earth, protecting our planet from the sun’s strong rays. At the same time, the atmosphere helps keep the Earth’s temperature comfortable for living beings – and it protects us from meteors, too!