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Old 04-04-2012, 08:33 PM   #87
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Lightbulb Bruce (crater)

Bruce is a small lunar impact crater located in the Sinus Medii. It lies to the west-northwest of the irregular crater Rhaeticus, and just to the west of the even smaller Blagg...The northern edge of the Sinus Medii is formed by a highland region, with the impact craters Murchison and Pallas along the border...At the far eastern end is the 220-km long Rima Ariadaeus rille which continues eastward to the edge of the Mare Tranquillitatis...

Mare Tranquillitatis (Latin for Sea of Tranquility) is a lunar mare that sits within the Tranquillitatis basin on the Moon...three small steps for man ...The three degrees of Craft or Blue Lodge giant leap for mankind.

The lunar maria are large, dark, basaltic plains on Earth's Moon, formed by ancient volcanic eruptions. They were dubbed maria, Latin for "seas", by early astronomers who mistook them for actual seas...In 1965, the Ranger 8 spacecraft crashed in Mare Tranquillitatis, after successfully transmitting 7,137 photographs of the Moon in the final 23 minutes of its mission...This mare was also the landing site for first manned landing on the Moon. After making a smooth touchdown in the Apollo 11 Lunar Module named Eagle, astronaut Neil Armstrong told flight controllers on Earth, "Houston, Tranquility Base here. The Eagle has landed." The landing area at 0.8° N, 23.5° E has been designated Statio Tranquillitatis after Armstrong's name for it, and three small craters to the north of the base have been named Aldrin, Collins, and Armstrong in honor of the Apollo 11 crew.

Bruce (crater)

Sinus Medii (latin for "Bay of the Center") is a small lunar mare that is located at the intersection of the Moon's equator and prime meridian. As seen from the Earth, this feature is located in the central part of the Moon's near side, and it is the point closest to the Earth. From this spot the Earth would always appear directly overhead, although the planet's position would vary slightly due to libration....In astronomy, libration is an oscillating motion of orbiting bodies relative to each other, notably including the motion of the Moon relative to Earth, or of Trojan asteroids relative to planets...The Moon generally has one hemisphere facing the Earth, due to tidal locking...Tidal locking (or captured rotation) occurs when the gravitational gradient makes one side of an astronomical body always face another; for example, the same side of the Earth's Moon always faces the Earth...

This feature is circular and cup-shaped, with no notable impacts overlaying the rim or interior. The interior has a generally higher albedo than the surrounding terrain, but there is a band of darker material cross the mid-point of the crater from west to east. It is surrounded by lunar mare, with a few tiny craterlets in the surface to the east...Colongitude 0° at sunrise

Sinus Medii...

In geography, the antipodes ( from Greek: ἀντίποδες, from anti- "opposed" and pous "foot") of any place on Earth is the point on the Earth's surface which is diametrically opposite to it. Two points that are antipodal (/ænˈtɪpədəl/) to one another are connected by a straight line running through the centre of the Earth...The Greek word is attested in Plato's dialogue Timaeus, already referring to a spherical Earth, explaining the relativity of the terms "above" and "below":

For if there were any solid body in equipoise at the centre of the universe, there would be nothing to draw it to this extreme rather than to that, for they are all perfectly similar; and if a person were to go round the world in a circle, he would often, when standing at the antipodes of his former position, speak of the same point as above and below; for, as I was saying just now, to speak of the whole which is in the form of a globe as having one part above and another below is not like a sensible man.

— Plato
The Prime Meridian of the Moon lies directly in the middle of the face of the moon visible from Earth and passes near the crater Bruce...A prime meridian is a meridian, i.e. a line of longitude, at which longitude is defined to be 0°...Note that the Moon is nearly invisible from the Earth at New Moon phase except during a solar eclipse...The Earth tides do act to deform the shape of the Moon, but this shape is one of an elongated ellipsoid (An ellipsoid is a closed quadric surface that is a three dimensional analogue of an ellipse...The rings of Saturn are circular, but when seen partially edge on they appear to be ellipses). with high points at both the sub- and anti-Earth points (The sub-Earth point is the location on the surface of the Moon where a particularly point on the Earth is directly overhead)... As an analogy, one should remember that there are two high tides per day on Earth, and not one...

Less than forty kilometres to the south-southeast is the original point of the selenographic coordinate system. From the floor of this crater the Earth always appears at the zenith...

Last edited by lightgiver; 04-04-2012 at 08:59 PM.
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