Galaxies, the Milky Way and our place in it

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   A galaxy is a smooth, round-to-oval glow with no arms. Which type is it, by Bo's reading (NASA)?

   • A nebula inside a star
   • Irregular
   • Elliptical
   • Spiral
2. 2.

   A galaxy is a patchy cloud of stars with no regular shape. Which type is it, by Kira's reading (NASA)?

   • A planet's ring
   • Irregular
   • Elliptical
   • Spiral

3. Read this first

   The Milky Way (NASA)

   Fact	Value
   disk width	more than 100,000 light-years
   Sun's distance from center	about 26,000 light-years (sources give 25,000 to 28,000)
   one orbit of the Sun	about 230 to 250 million years (sources differ)
   Andromeda	2.5 million light-years away

4. 3.

   Where is the Sun in the Milky Way, by Jun's reading (NASA)?

   • At the very center
   • Outside the galaxy
   • At the outer edge of the disk
   • About halfway out from the center, on a spiral arm
5. 4.

   About how wide is the Milky Way's disk of stars, by Luz's reading (NASA)?

   • About 8 light-minutes
   • About 100,000 km
   • About 100,000 years of travel by car
   • More than 100,000 light-years
6. 5.

   About how long does the solar system take to orbit the Milky Way's center once, by Milo's reading (NASA)?

   • About 230 to 250 million years
   • About 240 years
   • It does not orbit; the Sun is at the center
   • About one year
7. 6.

   Four nested-box cards, labeled A to D. Which list goes from smallest to largest, by Pia's reading?

   • Universe, galaxy, solar system
   • Solar system, galaxy, universe
   • Solar system, universe, galaxy
   • Galaxy, solar system, universe
8. 7.

   Ruler labeled 1 light-year. About how far does light travel in one year, by Ren's reading?

   • About 150 million km
   • Light arrives at once, so there is no distance
   • About 300,000 km
   • About 9.46 trillion km
9. 8.

   Map of the Local Group with the Milky Way, Andromeda and many small galaxies. What is the Local Group, by Tala's reading (NASA)?

   • The planets near the Sun
   • Over 50 galaxies, including the Milky Way and Andromeda
   • A cloud of dark matter alone
   • The stars in Orion

10. The Milky Way (NASA)

    Fact	Value
    disk width	more than 100,000 light-years
    Sun's distance from center	about 26,000 light-years (sources give 25,000 to 28,000)
    one orbit of the Sun	about 230 to 250 million years (sources differ)
    Andromeda	2.5 million light-years away

11. 9.

    Andromeda is 2.5 million light-years away. When did the light Zee sees from it tonight leave it?

    • About 8 minutes ago
    • Tonight, at the moment it is seen
    • About 2.5 million years ago
    • About 2.5 years ago
12. 10.

    Why do astronomers think galaxies hold unseen dark matter, by Esme's reading (NASA)?

    • Galaxies look dark between the stars
    • Dust blocks some starlight
    • Black holes fill each galaxy
    • Outer stars orbit too fast for the visible matter alone