In this blog post we will use Glowscript to create a 3D animation representing the revolution of the Earth around the Sun, and of the Moon around the Earth.

#### Earth Revolution

First, let’s calculate the angle of rotation needed to rotate the Earth around the Sun between two frames:

Here is our 3D animation: (Use Google Chrome to preview this animation)

*Right Click on the animation to change the view point (rotate camera angle).*

#### Find out more…

To learn more about all the instructions you can use in GlowScript/VPython, use this on-line documentation.

#### Task 1:

Complete this model further to add some of the other planets from he solar system. Below you will find the orbiting period for each planet. (The orbiting period of a planet corresponds to the number of days it takes for a planet to complete its revolution around the sun)

- Mercury: 88 days
- Venus : 225 days
- Earth: 365 days
- Mars: 687 days
- Jupiter: 4,333 days
- Saturn: 10,756 days
- Uranus: 30,687 days
- Neptune: 60,190 days

#### Task 2:

Though your model will not be up to scale you can improve it further to try to keep some of the proportions (e.g. size of planets, average distance of planets from the sun). For instance the diameter of planet Earth is twice the radius of planet Mars and four times the radius of the Moon.

Do some research to find more data about the planets online and resize and reposition your planets accordingly.

#### Task 3: Expert Level!

Not all planets orbit on the same 2D plan. Do some reading about the concept of orbital inclination. Can you update your model to take into consideration the orbital inclination of each planet?

#### Task 4: Expert Level!

The revolution of a planet around the sun does not follow a circular orbit but an elliptic orbit. Do some research about the elliptic orbit of planet Earth. Investigate how you could update your model to implement an elliptic orbit for your planets.

#### Solution...

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