Compare the planets, and where liquid water could exist

Grade 9 Science Worksheet

Circle the best answer.

1. Read this first

   Planets (NASA Planetary Fact Sheet)

   Planet	Distance (million km)	Mean temperature (°C)	Density (kg/m³)
   Mercury	57.9	167	5,429
   Venus	108.2	464	5,243
   Earth	149.6	15	5,514
   Mars	228.0	−65	3,934
   Jupiter	778.5	−110	1,326
   Saturn	1,432.0	−140	687

2. 1.

   How far is Mars from the Sun compared with Earth, by Bo's math?

   • About 1.5 times as far
   • The same distance
   • About 78 million km closer
   • About 0.66 times as far
3. 2.

   Earth (15 °C) and Mars (−65 °C) differ in average temperature by how much, by Esme's math?

   • 50 °C
   • 65 °C
   • 80 °C
   • −80 °C
4. 3.

   Water has a density of 1,000 kg/m³. Which planet in the table is less dense than water, by Jun's reading?

   • Saturn
   • Jupiter, at 1,326 kg/m³
   • Mars, the reddest planet
   • Each giant planet
5. 4.

   Habitable-zone distance grows as the square root of brightness; star 4 times the Sun's brightness. A star is 4 times as bright as the Sun. Since sunlight falls off with distance squared, how far out is its habitable zone compared with the Sun's, by Kira's math?

   • Half as far
   • The same distance
   • About twice as far
   • About 4 times as far
6. 5.

   Habitable-zone distance grows as the square root of brightness; star 1/100 of the Sun's brightness. A red dwarf gives off 1/100 of the Sun's light. Where is its habitable zone compared with the Sun's, by Luz's math?

   • About one-tenth as far
   • About 10 times as far away
   • About 1/100 as far
   • At the same distance

7. Diameters (NASA)

   Body	Diameter (km)
   Sun	1,391,400
   Jupiter	142,984
   Earth	12,756

8. 6.

   Using the same rule and table, about how big is the dip for an Earth-sized planet crossing the Sun, by Pia's math?

   • About 0.008%
   • About 9%
   • About 1%, like Jupiter
   • About 0.9%
9. 7.

   Why are Earth-sized planets easier to find around small red dwarfs than around Sun-like stars, by Ren's reading (NASA)?

   • Red dwarfs are brighter than the Sun
   • The dip is the same for any star
   • A small star loses a bigger share of its light
   • Planets glow more near red dwarfs

10. Planets (NASA Planetary Fact Sheet)

    Planet	Distance (million km)	Mean temperature (°C)	Density (kg/m³)
    Mercury	57.9	167	5,429
    Venus	108.2	464	5,243
    Earth	149.6	15	5,514
    Mars	228.0	−65	3,934
    Jupiter	778.5	−110	1,326
    Saturn	1,432.0	−140	687

11. 8.

    Mercury is closer to the Sun, yet Venus is hotter. What does this show about judging a planet's temperature, by Tala's reading?

    • The atmosphere matters, not just the distance
    • Venus must be closer than Mercury
    • The table must be wrong
    • Distance decides it alone
12. 9.

    Earth (5,514) and Mercury (5,429 kg/m³) are dense, while Saturn is 687. What does this fit, by Zee's reading?

    • Rocky planets are dense; gas giants are not
    • Gas giants are made of heavy rock
    • Dense planets are the biggest
    • The planets share one density
13. 10.

    Earth sits in the Sun's habitable zone, and Venus lies inside its inner edge. Which statement fits, by Ari's reading?

    • The zone is the same for any star
    • Venus is the cooler of the two
    • Both have oceans, since both are near the zone
    • Earth's surface can hold liquid water; Venus is too hot