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MARTIAN (AND OTHER EXTRATERRESTRIAL) MATH

Long division is boring, once you know how to do it, so use a calculator if you can. You can round off all the answers to the first two places. {If you want to use the metric system, multiply miles by 1.6 to convert them to kilometers, multiply feet by 0.305 to convert to meters, and multiply pounds by 0.45 to convert to weight in kilograms.}

1. The globe of the Earth is nearly 8000 miles in diameter. How far are you from the center? This distance is called the radius.
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2a. The orbit of the Moon is 480,000 miles in diameter. What is the radius of the Moon's orbit?
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2b. How many Earths would fit end to end across the orbit of the Moon?
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3. The Earth is 93,000,000 miles from the Sun. That's the radius of the Earth's orbit. How many times bigger is that than the radius of the Moon's orbit?
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4. Astronomers use the radius of the Earth's orbit (93 million miles) as a handy "yardstick" to measure other distances in the solar system. They call it 1 Astronomical Unit (abbreviated 1 AU). On the average, Mars is about 140,000,000 miles from the Sun. How many Astronomical Units is that?
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5. Pluto is the farthest known planet. Its average distance from the Sun is about 3,700,000,000 miles. How many Astronomical Units is that?
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ANSWER 5. The answer is 39 AU. So Pluto's orbit is 39 times bigger than the Earth's.

6a. If you plan to travel 150 miles at an average speed of 50 miles per hour, how long will your trip last? Use the fact that the time anything travels is the distance it travels divided by the speed.
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6b. On Mars, the Sojourner rover only goes about 80 feet per hour. (Why so slow? To keep out of trouble, but also because Sojourner only has about 16 watts of solar power). How long would it take the rover to move 160 feet?
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7. Now let's go a little faster! Pathfinder must travel about 312,000,000 miles along its curved orbit to get to Mars. How long would it take to fly that far at the average speed of a passenger jet, about 600 miles per hour?
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8. Now let's try the fastest speed in the universe! When Pathfinder lands on Mars, it will be 120,000,000 miles from Earth. The spacecraft communicates using radio waves, which travel at the speed of light -- 186,000 miles per second. How long will it take Pathfinder's first message from Mars to reach the Earth?
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9a. Gravity on Mars is only 38% as much as on Earth. Sojourner the rover weighs 25 pounds on Earth. How much does it weigh on Mars?
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9b. How much would you weigh on Mars?

9c. The Moon's gravity is about 6 times less than the Earth's. How much would you weigh on the Moon?

9d. The gravity of the tiny Martian moon Phobos is about 1000 times less than the Earth's. Horton the elephant weighs 10,000 pounds (about 5 tons) on the Earth. How much would Horton weigh on Phobos?
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10a. It takes 687 Earth days for Mars to orbit the Sun. That's one Mars year. How many Earth years is it?
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10b. How old are you in Mars years?

10c. Jupiter takes about 12 Earth years to orbit the Sun. How old are you in Jupiter years?

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MARTIAN (AND OTHER EXTRATERRESTRIAL) MATH

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