Stars, galaxies and the universe

Grade 6 Science Worksheet - Challenge Me

Circle the best answer.

1. Read this first

   Use this

   Nested boxes, not to scale, each box drawn inside the next. Box W: the Sun and its planets. Box X: Box W plus more than 100 billion other stars. Box Y: Box X plus over 50 other galaxies. Box Z: Box Y plus many more groups and clusters of galaxies.

2. 1.

   Box Z, the universe, is about 13.8 billion years old and still expanding (NASA). What is happening to the space between far-apart galaxy clusters, Bo?

   • It shrinks as the universe cools
   • It keeps growing
   • It grows inside our solar system instead
   • It stays the same as long ago
3. 2.

   Esme's classmate draws the Milky Way inside the solar system. Which fix is right?

   • Take out the Sun, since it is not a star
   • Keep it: the solar system is big enough to hold the whole galaxy
   • Swap them: the solar system is a tiny part of the Milky Way
   • Draw the two the same size
4. 3.

   Sirius is the brightest star in the night sky (NASA), yet the Sun outshines it by far. Which explanation fits, Kira?

   • Sirius is a planet
   • The Sun is a planet, so it glows more
   • The Sun is far closer to Earth
   • Sirius gives off no light of its own
5. 4.

   Luz reads about a faint star and a bright star that give off the same amount of light. Which claim, with its reason, fits?

   • The faint one is farther away, so less of its light reaches us
   • The faint one is hotter, since faint stars are red
   • The faint one is closer, since faint means near
   • The faint one is a planet, since stars are bright
6. 5.

   Galaxy card: round, no flat disk, made mostly of older stars. Milo must name the shape and one clue. Which answer fits?

   • Spiral: round, with older stars
   • Elliptical: it has spiral arms
   • Elliptical: round, with older stars
   • Irregular: it has no flat disk and no arms
7. 6.

   The Large and Small Magellanic Clouds are small galaxies about 160,000 light-years away that orbit the Milky Way. What are they, Noah?

   • Two stars in our solar system
   • Parts of the solar system's outer edge
   • Clouds of water in Earth's sky
   • Satellite galaxies of the Milky Way
8. 7.

   When two galaxies collide, the stars inside them do not crash into each other (NASA). Why not, Pia?

   • Galaxies have no stars in them
   • Stars are too small to have gravity
   • The stars bounce off each other like balls
   • The stars are very far apart
9. 8.

   Ren's friend says the universe has always looked the same as it does now. Which response is best?

   • Agree: the universe stays the same size
   • Disagree: it began hot and dense and has been expanding
   • Disagree: it began 4.6 billion years ago
   • Agree: the galaxies have stayed in the same fixed spots since the start
10. 9.

    A video says a light-year is how long a year lasts on a far planet. What should Tala write beside it in a class notebook?

    • Right: it is a time, like a calendar year
    • Not right: it is the speed of a spaceship
    • Right: it is the age of a star
    • Not right: a light-year is a distance, about 9.5 trillion km
11. 10.

    Zee's cousin says red stars are the hottest, since red means hot on a stove. Which response fits?

    • Agree: red is the hottest color for stars
    • Disagree: stars have no temperature
    • Agree: reddish Betelgeuse must be hotter than our yellow Sun
    • Disagree: blue stars are hotter; red stars are cooler