Spinning Cloud to Sun and Planets

In the picture

1. 1Bright central sphere: the young Sun gathering most of the cloud’s mass.
2. 2Swirling disk of gas and dust: the flattened cloud spinning around the center.
3. 3Small clumped sphere: dust and gas sticking together into a growing planet.
4. 4Curved arrows: material flowing around the center in the same direction.

Examples

• A whirlpool in a sink pulls floating bits toward the center while the water spins.
• A snowball rolling downhill gathers more snow and grows larger.

Quiz: Spinning Cloud to Sun and Planets (Age 12)

1. 1

   What caused the huge spinning cloud of gas and dust to collapse inward?

   • The cloud cooling down and shrinking
   • Gravity pulling the material inward
   • A giant explosion outside the cloud
2. 2

   Why did the center of the collapsing cloud become the young Sun?

   • It was the part that spun fastest
   • It stayed cooler than the rest of the cloud
   • It gathered most of the cloud’s mass
3. 3

   In the swirling disk around the young Sun, what happened to the gas and dust?

   • The disk stayed as a thin ring of ice and never changed
   • Small clumps stuck together and grew into planets
   • All the material was pushed away by the young Sun

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.