Wednesday, January 07, 2009

Man In The Moon

Molly teaches astronomy classes as part of her job, but she doesn't teach many astronomy classes during the winter. She decided to drag us out into the cold tonight to see what was happening in the universe. Unfortunately, there was just enough cloud cover to make seeing the stars a little difficult. We were however able to take a nice look at the moon and its craters.

The telescope we are using is an Orion SkyQuest XT4.5 Dobsonian Reflector Telescope. The XT4.5 is the smallest in the Orion Dobsonian line of telescopes. The telescope has surprisingly good optics for a telescope of this size. It comes with a good-quality 4.5" f/8 primary mirror, two eyepieces, a finder. The best thing about this telescope is the fact that it can be moved outside easily and set up quickly.

A few facts about the moon.

• How did the moon form? According to the "giant impact" theory, the young Earth had no moon. At some point in Earth's early history, a rogue planet, larger than Mars, struck the Earth in a great, glancing blow. Instantly, most of the rogue body and a sizable chunk of Earth were vaporized. The cloud rose to above 13,700 miles (22,000 kilometers) altitude, where it condensed into innumerable solid particles that orbited the Earth as they aggregated into ever larger moonlets, which eventually combined to form the moon.

• The moon is about 4.6 billion years old, or about the same age as Earth.

• The diameter of the moon is 2,160 miles (3,476 kilometers). The moon's mass—the amount of material that makes up the moon—is about one-eightieth of the Earth's mass.

The gravity of the moon is only one-sixth that of the Earth. That means that on the moon, Jake would only weigh about 31 lbs.

• The moon's rotation is synchronized in a way that causes the moon to show the same face to the Earth at all times.

• The moon's gravitational pull on the Earth is the main cause of the rise and fall of ocean tides.

• The airless lunar surface bakes in the sun at up to 243 degrees Fahrenheit (117 degrees Celsius) for two weeks at a time (the lunar day lasts about a month). Then, for an equal period, the same spot is in the dark. The dark side cools to about -272 degrees Fahrenheit (-169 degrees Celsius).

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