How the solar system formed

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   Timeline ruler in billions of years. About when did the solar system form, by Bo's reading (NASA)?

   • About 4.6 billion years ago
   • About 4,600 years ago
   • About 4.6 million years ago
   • About 13.8 billion years ago, with the universe
2. 2.

   What formed first at the center of the collapsing cloud, by Kira's reading (NASA)?

   • The Sun, from most of the material
   • Earth, the first planet
   • Jupiter, the biggest planet
   • The asteroid belt
3. 3.

   “then” Why did the collapsing cloud flatten into a disk, by Jun's reading (NASA)?

   • It spun faster as it shrank and flattened
   • Wind from Earth pushed it flat
   • It stopped spinning and spread out
   • It cooled into a flat sheet of rock
4. 4.

   Why do all eight planets orbit in nearly the same flat plane, by Luz's reading?

   • They were captured one at a time from space
   • They formed from one flat, spinning disk
   • The cloud did not spin
   • They broke off a larger planet
5. 5.

   Orbit diagram with the disk's spin direction marked. In which direction do the planets orbit the Sun, by Milo's reading?

   • Each in a random direction
   • All the same way, the way the disk spun
   • Inner one way, outer the other
   • They do not orbit; the Sun circles them
6. 6.

   Which planets are rocky terrestrial planets, by Noah's reading (NASA)?

   • Mercury, Venus, Earth and Mars
   • Earth and Jupiter
   • Saturn and Uranus
   • Jupiter, Saturn, Uranus and Neptune
7. 7.

   Orbit diagram with Uranus and Neptune marked. What are Uranus and Neptune called, by Ren's reading (NASA)?

   • Terrestrial planets
   • Ice giants
   • Dwarf planets
   • Gas giants, like Jupiter
8. 8.

   What are asteroids, by Tala's reading (NASA)?

   • Rocks thrown out by Earth's volcanoes
   • Pieces of a planet that blew apart
   • Pieces formed in just the last few thousand years or so
   • Rocky leftovers from the solar system's formation
9. 9.

   Sun, inner planets, Jupiter and an asteroid belt. Where are most asteroids found, by Zee's reading (NASA)?

   • Between Earth and the Moon
   • Inside Mercury's orbit
   • Between Mars and Jupiter
   • Where a lost planet broke up
10. 10.

    Orbit diagram with the Kuiper Belt beyond Neptune. What does NASA say the icy worlds of the Kuiper Belt, beyond Neptune, are, by Esme's reading?

    • Icy leftovers from the solar system's formation
    • Pieces broken off Neptune
    • New worlds forming today
    • Rocky planets like Earth