The Sun's life from start to finish

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   Timeline ruler of the Sun's life with a dot at now. The Sun is now fusing hydrogen into helium in its core. Which stage of life is it in, by Ari's reading?

   • Protostar
   • White dwarf
   • Main sequence
   • Red giant
2. 2.

   Drawing of the Sun swelling into a large red star. Late in its life, the Sun will swell to hundreds of times its size and glow red. What is this stage called, by Bo's reading?

   • Red giant
   • Main sequence
   • White dwarf
   • Supernova
3. 3.

   The Sun's last stage is a hot core about the size of Earth that slowly cools. What is it called, by Kira's reading?

   • White dwarf
   • A neutron star left by a supernova
   • A black hole
   • A small star still fusing hydrogen
4. 4.

   Which order matches the Sun's life from start to finish, by Jun's reading?

   • Nebula → protostar → main sequence → red giant → white dwarf
   • Protostar → red giant → main sequence → white dwarf
   • Nebula → main sequence → white dwarf → red giant
   • Nebula → protostar → main sequence → supernova
5. 5.

   What comes right after the main sequence for the Sun, by Luz's reading?

   • It explodes as a supernova
   • It goes dark at once
   • It shrinks straight to a white dwarf
   • It swells into a red giant
6. 6.

   What happens right before the Sun becomes a white dwarf, by Milo's reading?

   • Its outer layers drift away as a planetary nebula
   • A supernova blast
   • The main sequence begins
   • A protostar forms
7. 7.

   On the timeline, about how long ago did the Sun form, by Noah's reading (NASA)?

   • About 4.6 million years ago
   • About 4.6 billion years ago
   • About 10 billion years ago
   • About 4,600 years ago
8. 8.

   About how long is the Sun's main-sequence stage, by Pia's reading (NASA)?

   • About 10,000 years
   • About 10 billion years
   • About 100 years
   • About 4.6 billion years, ending now
9. 9.

   Star card cutaway of a red giant with its core marked. What does the core of a red giant like the future Sun fuse, by Tala's reading (NASA)?

   • Iron into gold
   • Nothing; fusion has stopped for good
   • Hydrogen into helium, just as now
   • Helium into carbon
10. 10.

    Why does a white dwarf glow, by Zee's reading (NASA)?

    • It reflects light from other stars
    • It is still hot and slowly cools; no fusion happens
    • It fuses hydrogen like the Sun today
    • It fuses helium in its core