How the solar system formed

Grade 9 Science Worksheet - Challenge Me

Circle the best answer.

1. 1.

   Drawing of a young star with a flat dusty disk around it. A young star is seen with a flat, spinning disk of gas and dust around it. What does the formation model predict, by Esme's reading?

   • The disk will turn into a second star
   • Giants close in, rocky planets farther out
   • Planets may form: rocky ones close in, giants farther out
   • Nothing; disks do not form planets
2. 2.

   If a cloud collapsed without spinning, what would the model predict, by Jun's reading?

   • No flat disk, so no neat set of orbiting planets
   • The same flat, spinning disk as before, with the same planets
   • Planets older than the star
   • Giants close to the star
3. 3.

   Luz's friend says the solar system formed in the Big Bang. Which response is best?

   • Agree: everything formed at once
   • Disagree: it formed about 9 billion years after the universe began
   • Agree: the Sun and planets are 13.8 billion years old, the universe's age
   • Disagree: it formed a few thousand years ago
4. 4.

   Milo's cousin says the asteroid belt is a planet that exploded. Which response is best (NASA)?

   • Disagree: it is gas, not rock
   • Agree: Jupiter's gravity smashed a planet that once orbited there
   • Disagree: it is material that never formed a planet
   • Agree: a planet broke apart there
5. 5.

   Disk with a hot inner zone and a cold outer zone. Noah's friend says Jupiter is a gas giant because it formed closest to the Sun's heat. Which response is best?

   • Agree: the Sun puffed it up with gas
   • Agree: heat makes gas planets
   • Disagree: Jupiter is a rocky planet
   • Disagree: it formed far out, where ices and gases could gather
6. 6.

   4.6 billion years = 24 hours; universe about 13.8 billion years. On that same 24-hour day, how many hours ago did the universe begin, about 13.8 billion years before today, by Ren's math?

   • About 24 hours ago, at the same moment
   • About 13.8 hours ago
   • About 8 hours ago
   • About 72 hours ago
7. 7.

   Meteorite samples and asteroids are dated to about 4.6 billion years. Earth's surface rocks are mostly much younger. Why, by Tala's reading?

   • Earth's surface keeps changing, but leftovers have not
   • Asteroids are pieces of an older planet
   • Earth formed long after the asteroids
   • The dates mean the solar system is young and still forming
8. 8.

   Thousands of planetary systems are now known (NASA). Why do astronomers compare them with our solar system, by Zee's reading?

   • To test whether the formation model works for other stars
   • Because they formed in the Big Bang
   • To find planets that broke apart into asteroid belts like ours
   • To show each system matches ours exactly
9. 9.

   Comets from the far outer solar system are rich in ice. Why does that fit the model, by Ari's reading?

   • Ice formed near the hot Sun
   • Comets broke off Earth's oceans
   • Comets formed recently from Earth's water
   • Ice survived in the cold outer disk, where they formed
10. 10.

    Four evidence cards, labeled A to D. Which evidence best supports a spinning disk origin, by Bo's reading?

    • The asteroid belt is a broken planet
    • The planets have different colors
    • Rocky planets are found farthest from the Sun, and giants closest
    • Planets orbit in nearly one plane, in one direction