Objects - The Moon

Obects & Observing Tips:

The Moon

[photo by Neal Olson, through Haggart's 24" reflector]

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Moon Facts
Distance from Earth	Mean: 384,400 km Range: 363,300 - 405,500 km
Temperature	-233° C - 123° C
Mass	7.3x10^{22 kg}	^{1.2% that of Earth}
Diameter	3,476 km	27% that of Earth
Gravity	1/6th that of Earth
Volume	21 million km³	2% that of Earth
Density	3.3 g/cm³	60% that of Earth
Magnitude	-12.7 at full moon
Apparent diameter	31 arcminutes
Rotation period	27.3 Earth days
Age	4.5 billion years
Orbit	inclined 5° to the ecliptic
Composition	Much like the outer layers of the Earth. The Moon lacks a heavy metal core. Basalt and breccia rocks have been found on the surface.
Data sources: NASA factsheet and Solar System Exploration site (see below) Robert Burnham et al., Advanced Skywatching, 1997

Other Facts

Origin: the most widely-accepted current theory is that an asteroid smashed into the Earth splashing huge amounts of Earth and asteroid into space where they came together to form the Moon. Other hypotheses are (1) that the Moon was formed in same nursery nebula at same time as Earth, and would have been a planet were it not captured by Earth's gravity, or (2) that the Moon was a wanderer meandering through the Solar System only to be captured by Earth's gravitational pull.
Geography: Interesting mountains, valleys, "seas" and impact craters. Mountains and valleys and craters formed by asteroid impact. "Seas"are not actual oceans but low portions of the Moon inundated in lava from ancient volcanos. They appear as smooth,dark areas. In the year 1178, British monks reported what appeared to be a great impact by asteroid. The moon is still quivering to this day as a result of this holocaust. Scientists believe they can identify the enormous rays radiating forth from this crater.
Travel time: Apollo missions took 3 days. (Would be quicker today with modern technology.)
Solar Eclipse: Sun is blocked by the moon.
Tides: High tides are created by the gravitational pull of the Moon every 12 hours and 25 minutes.

Observing Notes

Use a Moon filter! The Moon has such a reflective surface that looking at it in a telescope without a filter will knock your night vision out for a while. Moon filters cut out about 87% of the light so that you can view it comfortably for an extended period.
Different features are best observed during different phases of the moon.
It's particularly interesting to watch features along the "terminator" - the line of light and shadow.

Exploratory Missions

Men on the Moon: the first humans arrived on the Moon July 20, 1969 by Apollo 11 spacecraft.
Today there are scientists arguing for the establishment of a scientific base on the moon. This would be a valuable scientific asset. Also, there are those who argue strongly in behalf of a scientific base in order to spot asteroids sooner in hopes to identify and possibly deflect potentially hazardous asteroids on their way to Earthly collision.

Mythology

Name: Luna, from Latin means "to shine." Associated with Diana, Roman goddess of the hunt.

Websites for Information on the Moon:

Bibliography:

Mackenzie, Dana. The Big Splat, or, How Our Moon Came To Be. Wiley, 2003, 240p.