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
   • Nothing; disks do not form planets
   • Planets may form: rocky ones close in, giants farther out
2. 2.

   A planetary system has a Jupiter-sized giant very close to its star. Why is this a puzzle for the simple model, by Kira's reading?

   • It must be a rocky planet
   • It shows the star formed after the planet
   • Giants are expected close in, so there is no puzzle
   • Giants should form far out, so it may have moved inward
3. 3.

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

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

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

   • Agree: a planet broke apart there
   • Disagree: it is material that never formed a planet
   • Disagree: it is gas, not rock
   • Agree: Jupiter's gravity smashed a planet that once orbited 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
   • Disagree: it formed far out, where ices and gases could gather
   • Agree: heat makes gas planets
   • Disagree: Jupiter is a rocky planet
6. 6.

   4.6 billion years = 24 hours. If the solar system's 4.6 billion years were one 24-hour day, about how long would 1 million years last, by Pia's math?

   • About 19 seconds
   • About 19 hours
   • About 0.19 seconds
   • About 1 minute
7. 7.

   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 72 hours ago
   • About 13.8 hours ago
   • About 8 hours ago
8. 8.

   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?

   • The dates mean the solar system is young and still forming
   • Earth's surface keeps changing, but leftovers have not
   • Earth formed long after the asteroids
   • Asteroids are pieces of an older planet
9. 9.

   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
   • To show each system matches ours exactly
   • Because they formed in the Big Bang
   • To find planets that broke apart into asteroid belts like ours
10. 10.

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

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