Moons and Planets in Orbit

In the picture

1. 1The star at the centre: the body that holds the planet on its path
2. 2The blue planet: a body circling the star
3. 3The small grey moon: a natural satellite circling the planet
4. 4The dotted loop around the planet: the moon’s repeating path
5. 5The dotted loop around the star: the planet’s repeating path

Examples

• The Moon circling Earth about once every 27 days
• Earth circling the Sun once every 365 days

Quiz: Moons and Planets in Orbit (Age 14)

1. 1

   Why does a moon stay in orbit instead of falling into its planet?

   • It is held in place by a solid ring around the planet.
   • It moves sideways fast enough to keep missing the planet.
   • It has no gravity pulling it toward the planet.
2. 2

   What does every orbit balance?

   • The star’s brightness and the planet’s heat.
   • The moon’s size and the planet’s distance.
   • Gravity pulling inward and sideways motion carrying the body forward.
3. 3

   According to the card, what is the star’s role?

   • It is the body that holds the planet on its path.
   • It is the repeating path that the moon follows.
   • It is a natural satellite that circles the planet.

The answers, each with its explanation, are in the app. This lesson has left the free week, so its quiz is part of the subscription.