Astronomy 2e

# Figuring for Yourself

Astronomy 2eFiguring for Yourself

### Figuring for Yourself

28.

Estimate the amount of water there could be in a global (planet-wide) region of subsurface permafrost on Mars (do the calculations for two permafrost thicknesses, 1 and 10 km, and a concentration of ice in the permafrost of 10% by volume). Compare the two results you get with the amount of water in Earth’s oceans calculated in Example 10.1.

29.

At its nearest, Venus comes within about 41 million km of Earth. How distant is it at its farthest?

30.

If you weigh 150 lbs. on the surface of Earth, how much would you weigh on Venus? On Mars?

31.

Calculate the relative land area—that is, the amount of the surface not covered by liquids—of Earth, the Moon, Venus, and Mars. (Assume that 70% of Earth is covered with water.)

32.

The closest approach distance between Mars and Earth is about 56 million km. Assume you can travel in a spaceship at 58,000 km/h, which is the speed achieved by the New Horizons space probe that went to Pluto and is the fastest speed so far of any space vehicle launched from Earth. How long would it take to get to Mars at the time of closest approach?

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