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The Moon
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| [Note Guidelines] Photographer's Note |
The Moon (Latin: Luna) is Earth's only natural satellite, and the fifth largest moon in the Solar System. The average centre-to-centre distance from the Earth to the Moon is 384,403 km, which is about thirty times the diameter of the Earth. The Moon has a diameter of 3,474 km slightly more than a quarter that of the Earth and slightly smaller than the east-west distance across the United States. This means that the volume of the Moon is about 2 percent that of Earth. The gravitational pull at its surface is about 17 percent of the Earth's. The Moon makes a complete orbit around the Earth every 27.3 days, and the periodic variations in the geometry of the Earth–Moon–Sun system are responsible for the lunar phases that repeat every 29.5 days.
The Moon is the only celestial body to which humans have travelled and upon which humans have landed. The first artificial object to escape Earth's gravity and pass near the Moon was the Soviet Union's Luna 1, the first artificial object to impact the lunar surface was Luna 2, and the first photographs of the normally occluded far side of the Moon were made by Luna 3, all in 1959. The first spacecraft to perform a successful lunar soft landing was Luna 9, and the first unmanned vehicle to orbit the Moon was Luna 10, both in 1966. The United States (U.S.) Apollo program achieved the only manned missions to date, resulting in six landings between 1969 and 1972. Human exploration of the Moon ceased with the conclusion of the Apollo program, although several countries have announced plans to send people or robotic spacecraft to the Moon.
Two sides of the Moon
The Moon is in synchronous rotation, meaning that it keeps nearly the same face turned towards the Earth at all times. Early in the Moon's history, its rotation slowed and became locked in this configuration as a result of frictional effects associated with tidal deformations caused by the Earth.Long ago when the Moon spun much faster, the Moon's tidal bulge preceded the Earth-Moon line because the Moon couldn't "snap back" its bulges quickly enough to keep its bulges in line with Earth. The rotation swept the bulge beyond the Earth-Moon line. This out-of-line bulge caused a torque, slowing the Moon spin, like a wrench tightening a nut. When the Moon's spin slowed enough to match its orbital rate, then the bulge always faced Earth, the bulge was in line with Earth, and the torque disappeared. That's why the Moon rotates at the same rate as it orbits and we always see the same side of the Moon. Small variations (libration) in the angle from which the Moon is seen allow about 59% of its surface to be seen from the earth (but only half at any instant)
From Wikipedia, the free encyclopedia |
eqshannon, bobair has marked this note useful
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- demeve
![Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 603 W: 11 N: 1627]](http://i1.treknature.com/misc/g-s-g.gif)
(5989) - [2008-09-12 21:45]
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Hello Tom,
We're neighbors today, this is a fantastic picture, just
earlier today I was looking at the moon in this mini observatory in park not far from home.. Fantastic..
Everton
Nice shot..I saw it last night and was telling Jane...it is getting very close to full..I had some super images of it..I'll find one and put it in workshop because it was not good enough to post on TN, but intriguing how the moon attracts us so much yes? Yours is fine..mine was taken from my electric Scooter 2 nights ago...I have a small grip holder that clamps the camera to the steering mechanism..:-)
Bob
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- bobair
![Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 397 W: 118 N: 1419]](http://i1.treknature.com/misc/g-g-g.gif)
(5126) - [2008-09-13 9:30]
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Hi Tom,
this is an exceptional looking capture of our nearest neighbor in space.The details and and sharpness are first rate, given the gear that you use and for the rest of us as well.To get even better shots we all need to have telescopes and that is an expensive proposition.Everything about this capture is spot on and I see no way of improving it as the contrast and sharpness are beyond reproach.Thanks Tom for giving us a chance to see your wonderful capture of the moon. Bob
What a cool shot of the moon, I've always wanted to make a capture like this one but just haven't gotten around to it yet, great job.
TFS
TK
