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)?

   • 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
   • A cloud of gas and dust collapsed under its own gravity
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 4,600 years ago
   • About 4.6 billion years ago
   • About 4.6 million years ago
3. 3.

   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
4. 4.

   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
   • They do not orbit; the Sun circles them
   • Each in a random direction
   • All the same way, the way the disk spun
5. 5.

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

   • Earth and Jupiter
   • Mercury, Venus, Earth and Mars
   • Jupiter, Saturn, Uranus and Neptune
   • Saturn and Uranus
6. 6.

   Disk with a hot inner zone and a cold outer zone. Why did rocky planets form near the Sun, by Pia's reading (NASA)?

   • Gas was heavier and sank to the middle
   • Ice was most common near the Sun
   • The Sun threw rocks out to them
   • Only rock could withstand the heat near the young Sun
7. 7.

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

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

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

   • Rocks thrown out by Earth's volcanoes
   • Pieces formed in just the last few thousand years or so
   • Pieces of a planet that blew apart
   • 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)?

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

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