Stars, galaxies and the universe

Grade 6 Science Worksheet

Circle the best answer.

1. Read this first

   Galaxy seen from above, not to scale

   a flat disk with a central bulge and spiral arms, more than 100,000 light-years across. Dot S sits on one spiral arm, about halfway from the center to the edge.

2. 1.

   In the galaxy drawing, dot S marks the Sun. Where in the Milky Way is the Sun, Ari?

   • On a spiral arm, about halfway out
   • At the outer edge, past the arms
   • Outside the galaxy, looking in
   • At the very center of the galaxy
3. 2.

   Bo reads that, from a dark place, the Milky Way looks like a faint milky band across the sky. Why a band?

   • It is the light of one huge star
   • It is the light of the solar system's planets
   • We see the galaxy's flat disk edge-on from inside
   • It is a thin cloud in Earth's air
4. 3.

   Esme lists four things from smallest to largest for a poster. Which order is right?

   • Earth, solar system, Milky Way, Local Group
   • Earth, solar system, Local Group, Milky Way
   • Solar system, Earth, Milky Way, Local Group
   • Earth, Milky Way, solar system, Local Group
5. 4.

   Proxima Centauri is 4.24 light-years away. What does a light-year measure, Jun?

   • A time: how long a spaceship takes to get there
   • A time: the length of a year on Proxima
   • A distance: how far light goes in a year
   • A brightness: how much light a star gives off
6. 5.

   The Andromeda Galaxy is about 2.5 million light-years away (NASA). When did the light that reaches Luz tonight leave it?

   • About 2.5 million years ago
   • Just last night
   • About 2.5 billion years ago
   • About 2.5 million seconds ago

7. Use this

   Star color card (NASA), columns Surface temperature, Color and Example. About 3,000 °C: reddish, like Betelgeuse. About 5,500 °C: yellow, like the Sun. About 12,000 °C: blue, like Rigel.

8. 6.

   Star K looks blue, and star M looks reddish. Using the color card, which statement is true, Milo?

   • Star M has the hotter surface
   • Star K has the hotter surface
   • Color says nothing about temperature
   • Both have the same temperature
9. 7.

   Proxima Centauri is a red dwarf, the smallest kind of main sequence star (NASA). What else is true of red dwarfs, Noah?

   • They are hotter than blue stars
   • They are the hottest main sequence stars
   • They are planets, not stars
   • They are the coolest main sequence stars
10. 8.

    About 90% of stars, the Sun included, are main sequence stars (NASA). What is happening in their cores, Pia?

    • Helium is splitting into hydrogen
    • Hydrogen is fusing into helium
    • Nothing, as their cores are cold
    • Coal is burning
11. 9.

    Ren makes a time line, oldest first. Which order matches NASA's history of the universe?

    • The Sun forms, universe begins, first stars, today
    • Together in one moment, as the universe stays the same
    • Universe begins, first stars, the Sun forms, today
    • First stars, the Sun forms, universe begins, today
12. 10.

    In 1929, astronomers found that the universe is expanding. What does that tell Tala about the far past?

    • Galaxies are shrinking
    • It began expanding in 1929
    • It was once smaller and much hotter
    • It has stayed the same size