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?

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

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

   Earth 365.2 days; Neptune 59,800 days. Neptune takes about 59,800 days to orbit the Sun (NASA). About how long is one Neptune year, as Jun works it out?

   • Less than an Earth year, since it is farther
   • About 164 Earth years
   • About 16 Earth years
   • About 1 Earth year
5. 4.

   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?

   • Closer planets move faster in their orbits
   • The planets share one speed
   • Farther planets move faster
   • Bigger planets move faster
6. 5.

   “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?

   • The Moon pushes it around
   • Nothing; Earth would orbit anyway
   • The Sun's gravity pulling toward the center
   • Its speed alone makes it curve
7. 6.

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

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

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

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

   • Nothing; stars drift freely
   • The Sun's gravity alone
   • Gravity
   • Light holding them in place
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 230 years
    • About 230 to 250 million years
    • About one year
    • The Sun stays still; it does not orbit
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?

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