Galaxies, the Milky Way and our place in it

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   “Sketch of a” A galaxy has a bright center and a flat disk with arms winding out. Which type is it, by Ari's reading (NASA)?

   • Elliptical
   • Spiral
   • Irregular
   • A solar system
2. 2.

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

   • Irregular
   • A nebula inside a star
   • Elliptical
   • Spiral
3. 3.

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

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

4. 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

5. 4.

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

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

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

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

   Ruler labeled 1 light-year. What is a light-year, by Noah's reading?

   • The brightness of a star
   • The distance light travels in one year
   • One year on a planet near a star
   • The time light takes to cross the galaxy
8. 7.

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

   • Solar system, universe, galaxy
   • Universe, galaxy, solar system
   • Galaxy, solar system, universe
   • Solar system, galaxy, universe
9. 8.

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

   • About 9.46 trillion km
   • Light arrives at once, so there is no distance
   • About 150 million km
   • About 300,000 km
10. 9.

    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 stars in Orion
    • The planets near the Sun
    • Over 50 galaxies, including the Milky Way and Andromeda
    • A cloud of dark matter alone
11. 10.

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

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