How gravity holds the solar system together

Grade 6 Science Worksheet

Circle the best answer.

1. Read this first

   Use this

   Table (NASA Planetary Fact Sheet), with columns Planet, Distance (millions of km) and Orbit time (days), distance from the Sun and orbit time: Mercury 57.9 million km, 88.0 days; Earth 149.6 million km, 365.2 days; Mars 228.0 million km, 687.0 days; Jupiter 778.5 million km, 4,331 days.

2. 1.

   Bo reads the NASA table of orbit times. What pattern does it show?

   • Each planet takes one Earth year
   • Planets farther from the Sun take longer to orbit
   • Farther planets orbit faster
   • Bigger planets orbit faster
3. 2.

   Earth 365.2 days; Mars 687.0 days. Mars takes 687.0 days to orbit the Sun. About how many Earth years is that, by Esme's math?

   • About half a year, since it is farther
   • About 1.9 years
   • About 6.9 years
   • Exactly one year
4. 3.

   Mercury 47.4 km/s; Earth 29.8 km/s; Jupiter 13.1 km/s; Neptune 5.4 km/s. Kira reads the NASA table of orbit speeds. What does the table show?

   • Farther planets move faster
   • Bigger planets move faster
   • The planets share one speed
   • Closer planets move faster in their orbits
5. 4.

   “Orbit diagram from above, not to scale:” Earth moves about 29.8 km every second around the Sun. What keeps that fast motion bent into an orbit, says Milo?

   • Nothing; Earth would orbit anyway
   • The Moon pushes it around
   • The Sun's gravity pulling toward the center
   • Its speed alone makes it curve
6. 5.

   Which two things together make an orbit, according to Noah's notes?

   • A pull toward the center and fast sideways motion
   • A push from behind and solar wind
   • Fast sideways motion by itself
   • A pull toward the center by itself
7. 6.

   “Orbit diagram from above, not to scale:” Imagine Earth suddenly stopped moving sideways along its orbit. What would the Sun's gravity do, as Pia predicts?

   • Pull Earth straight toward the Sun
   • Nothing; Earth would stay put
   • Keep Earth orbiting just as before
   • Push Earth away from the Sun
8. 7.

   A small science payload is launched straight up a few hundred kilometers with no sideways speed. What happens next, by Ren's reasoning?

   • It floats in place, since gravity stops
   • It falls back to Earth
   • The air pushes it away into space
   • It settles into orbit
9. 8.

   What holds the billions of stars of the Milky Way together, as Tala reads?

   • Gravity
   • The Sun's gravity alone
   • Light holding them in place
   • Nothing; stars drift freely
10. 9.

    Drawing of a spiral galaxy seen from above, with the Sun's position marked and an orbit arrow around the center. The Sun orbits the center of the Milky Way. About how long does one trip take, according to NASA and Zee's notes?

    • About one year
    • About 230 to 250 million years
    • The Sun stays still; it does not orbit
    • About 230 years
11. 10.

    Drawing of a spiral galaxy seen from above, with a bar labeled about 100,000 light-years. The Milky Way is about 100,000 light-years across. What does gravity do at that huge size, by Ari's reading?

    • Gravity stops at the edge of the solar system
    • The galaxy is held together by wind
    • Gravity works just near planets
    • It still holds the whole galaxy together