The Moon
Our nearest neighbour
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The origin of the Moon, sometimes referred to as the "Big Splash", is based on the similarity between it's composition and the Earth's mantle or outer layers, as determined from retrieved lunar soil samples. A (proto)planet is believed to have collided with the cooling Earth and merged with it, but some of the scattered Earth's mantle material subsequently agglomerated to form the Moon.
Crater Copernicus with it's smaller neighbour Eratosethenes. A Schmidt-Newtonian image on 28 Nov. 1998 using LPR filter and 6 mm orthoscopic eyepiece projection. Exposure time of 1.6 sec.
Montage of 6 Moon images at prime focus with 200mm f/4 Schmidt-Newtonian on 28 Dec. 1998. Exposure time of 0.01 - 0.02 sec.
Click on image for full size.
The Moon rotates on it's axis in a mean 27 days, which is the same time it takes to make one orbit around the Earth. This is the consequence of synchronous rotation produced through tidal forces between the bodies. As a result, the Moon presents the same face to the Earth, with a few irregularities known as libration. It's orbit gives rise to various phases of illumination from New (minimal) to Full (maximum) Moon dependent upon the Earth and Moon relative positions to the Sun. In detail, the orbit is very complex, due to Earth and Sun interactions. Once solved, however, it was a useful tool to determine longitude at sea, and an earlier solution in 1757 than Harrison's chronometer.
Crater Bianchini in Northern Uplands at edge of Sinus Iridum in Jura mountains. Laplace Prom vista is at end of the prominence. A Schmidt-Newtonian image on 29 Nov. 1998 using LPR filter and 6 mm orthoscopic eyepiece projection. Exposure time of 1.6 sec.
Crater Capuanus (upper left ) with it's neighbours Ramsden, Campanus and Vitello. A Schmidt-Newtonian image on 29 Nov. 1998 using LPR filter and 6 mm orthoscopic eyepiece projection. Exposure time of 1.6 sec.
The darker and smoother areas are called Maria (Latin for "seas"). They are lava filled basins of which Mare Imbrium is one of the largest and most apparent. Numerous craters exist as a record, it is believed, of past meteoroid bombardment, though some craters indicate a volcanic origin. The craters often have central peaks. Mountain ranges are evident between the craters and at the edges of of the maria basins. Rays or bright streaks emanate from some craters such as Tycho and Copernicus, and are probably splash zones of debris thrown up from the impact craters. The Moon is lifeless, it is thought, with no atmosphere.
Crater J Herschel (right) in Northern Uplands with Fontenelle (top left) and Philolaus (lower left). A Schmidt-Newtonian image on 29 Nov. 1998 using LPR filter and 6 mm orthoscopic eyepiece projection. Exposure time of 1.6 sec.
Crater Gassendi. A Schmidt-Newtonian image on 29 Nov. 1998 using LPR filter and 6 mm orthoscopic eyepiece projection. Exposure time of 1.6 sec.
There is a strong interaction between the Moon and the Earth as particularly evidenced in tidal behaviour. In earlier times, the Moon was even closer with the tidal changes more extreme, and probably very influential on life originating and developing on Earth.
More of my Moon images can be viewed by clicking here.
Other information and images of the Moon can be found at the JPL / NASA site.
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