How the solar system formed

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   a cloud, a spinning disk, young planets, today's solar system. How did the solar system begin, by Ari's reading (NASA)?

   • A cloud of gas and dust collapsed under its own gravity
   • The Sun spun off the planets later
   • A planet broke apart into pieces
   • It formed during the first few minutes after the Big Bang began
2. 2.

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

   • About 13.8 billion years ago, with the universe
   • About 4.6 billion years ago
   • About 4.6 million years ago
   • About 4,600 years ago
3. 3.

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

   • Jupiter, the biggest planet
   • The Sun, from most of the material
   • The asteroid belt
   • Earth, the first planet
4. 4.

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

   • It spun faster as it shrank and flattened
   • It stopped spinning and spread out
   • Wind from Earth pushed it flat
   • It cooled into a flat sheet of rock
5. 5.

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

   • The cloud did not spin
   • They formed from one flat, spinning disk
   • They broke off a larger planet
   • They were captured one at a time from space
6. 6.

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

   • Inner one way, outer the other
   • All the same way, the way the disk spun
   • They do not orbit; the Sun circles them
   • Each in a random direction
7. 7.

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

   • Saturn and Uranus
   • Earth and Jupiter
   • Mercury, Venus, Earth and Mars
   • Jupiter, Saturn, Uranus and Neptune
8. 8.

   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
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
   • Between Mars and Jupiter
   • Inside Mercury's orbit
   • 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?

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