Moon

Moon
The Moon one week after full moon
Orbital characteristics
Primary	Earth
Perigee	363,300 km
Apogee	405,500 km
Semi-major axis	384,400 km
Mean orbital radius	378,000 km
Orbital eccentricity	0.0549
Sidereal month	27.3217 da
Synodic month	29.530588 da
Avg. orbital speed	1.023 km/s
Inclination	18.28° to Earth's equator
Rotational characteristics
Sidereal day	27.3217 da
Solar day	29.530588 da
Physical characteristics
Mass	7.35 * 1022 (1.23% earth)
Density	3350 kg/m³
Mean radius	1737.1 km
Equatorial radius	1738.1 km
Polar radius	1736.0 km
Surface gravity	1.62 m/s² (0.165 g)
Escape speed	2.38 km/s
Surface area	37,919,000 km² (7.434% earth)
Minimum temperature	100 K
Mean temperature	250 K
Maximum temperature	400 K
Albedo	0.12
Magnetosphere
Magnetic dipole moment at present	1.3 * 1015 N-m/T
Magnetic dipole moment at creation	1.73 * 1022 N-m/T
Decay time	364 a
Half life	252.3 a

The Moon is a natural satellite orbiting the Earth at an average distance of about 238,000 miles (380,000 km).

Unlike most planets in the solar system, Earth has only one moon. To those on Earth the Moon appears as a pale disc which goes through phases in which greater or lesser amounts of the side lit by the sun are visible from Earth.

The Moon as God's creation

The Earth's moon has several striking characteristics. To many, these characteristics appear as "clues" or "hints" left by God for men to discover.

Size of its disc

The Moon appears to have the same size as the Sun when viewed from Earth. This creates a unique symmetry and phenomenal solar eclipses. The odds of this occurring by chance are nearly zero.

Rotation and revolution

The Moon presents the same side to Earth at all times. That means that the rotation of the Earth offsets the separate effects of the revolution of the Moon. Physical explanations rely on tidal locking, asserting that tidal forces on Earth caused a bulge on the Moon, thereby creating a drag on the rotation of the Moon until its same face always presents to the Earth. In fact, current tidal forces exerted by the Earth on the Moon cannot account fully for its bulge or egg shape.

Origin theories

Atheistic theories of the origin of the Moon, widely taught for decades despite lacking the falsifiability requirement of science (see Philosophy of science), have been proven false. Lacking any other atheistic alternatives, some scientists assert that the Moon originated from a collision early in Earth's history which created an orbiting ring of debris from the iron-poor surface of the planet which eventually coalesced into the moon. This theory, however, is contrary to key observations of the Moon, such as the relatively low levels of iron in the Moon's crust. Additional tests fail to support the atheistic theory.
Biblical history records the Moon being created on the fourth day of creation week, along with the Sun.

Rate of recession

The Moon currently recedes from the Earth at a rate of 1.5 inches (3.8 cm) per year, and is believed by mainstream scientists to be 4.6 billion years old .
The Moon could never have been closer than about 11,000 miles or it would have been broken up by tidal forces.
If the rate of recession stayed constant at 3.8 cm per year, it would take 9.6 billion years for the lunar distance to migrate from 11,000 miles to the present distance of about 240,000 miles.
However, the rate of recession would not have been constant, but would have been greater in the past, so that extrapolating backwards in time results in the moon being in contact with the earth 1.37 billion years ago, seemingly (if the assumptions stated above are correct) contradicting the view of an Old Earth promoted by atheists.

Impact Craters

Uniformitarian astronomers assume that crater impacts are a reliable indicator of the age of a celestial body. True to the form and principles of uniformitarianism (as applied to astronomy rather than to geology), any such estimation relies upon uniform constants and weather/erosion trends. Recent research into crater impacts on the moon suggests that many of the assumptions previously made are unwarranted. Bonnie Buratti of NASA's Jet Propulsion Laboratory has asserted that space weathering "takes place very rapidly on the Moon." Peter Brown of the University of Western Ontario insists that there is no absolute criteria for the dating of craters.

Danny Faulkner of the Institute for Creation Research has observed that many of the lunar maria contain ghost craters, or craters that the lava flow that produced the maria seem to have filled only partially. In the deep time scale required by uniformitarianism, the ghost craters are the result of impacts that occurred as much as half a gigayear before the crust-fracturing impacts that caused the lava flows. This is not a reasonable assumption, because any impact strong enough to crack the crust should have obliterated any craters previously extant. Faulkner thus concludes that the impacts that formed the ghost craters, and those that let loose the lava flows that formed the maria, occurred within days of one another and were probably part of at least one system-wide catastrophe involving a narrow stream of meteoroids and/or comets that delivered a concentrated bombardment of the Earth and Moon in a short interval.

Faulkner assumes that this system-wide catastrophe occurred during the year of the Great Flood. But in 1984, Russell Humphreys, then at the Sandia National Laboratories, developed evidence suggesting different dates entirely. Specifically, the Project Apollo exploration teams brought back many samples of basalt (an igneous rock) and brecchia (pulverized meteor-impact remains). Geologists analyzed both types of samples and found evidence that each type of rock had once been in a magnetic field far more powerful than that which the Moon has today. Using his model for the creation and decay of magnetic fields, Humphreys determined that the basalt had been laid down about 370 years after creation, and the brecchia had been laid down 1840 years after creation, or about 190 years after the Flood. These findings clearly suggest that the Moon, and presumably all other bodies in the solar system, have been subject to two separate system-wide bombardments, one occurring in the second or third generation after the fall of man and the other occurring well after the Flood.

Tides

The gravitational force of the Moon causes the ocean tides; these tidal forces have other effects as well. These tidal forces have the effect of creating resistance which slows down the rotation of both objects. In the case of the Earth, the result is that the Earth's rotation slows on the order of one millisecond per century. The Moon's rotation is locked in to its period of revolution, and the same side of the Moon always faces the Earth.

The "dark" or far side

The phrase "the dark side of the Moon" is inaccurate because the Moon does rotate relative to the Sun, with the same period as its period of revolution, once every 29 days. Our view of the Moon from the Earth always shows the same side of the Moon, with the same markings and features. When the Moon is full, the entire side that faces us is experiencing lunar "day" and is lit by the Sun. Two weeks later, when the Moon is new, the side that faces us is experiencing solar "night" and is unlit (and virtually invisible).

The far side of the moon is far more heavily cratered than the near, and the predominant type of cratering is consistent with brecchia-forming meteor impact. This would suggest that the far side suffered its bombardment in the latter of the two catastrophes that Humphreys suggests that the Moon has suffered.

Due to a slight "wobble" in the lunar motion called libration, we actually see a little bit more than half of the Moon's surface; sometimes it is turned a bit one way and sometimes the other. However, nobody had any idea of what the far side of the Moon looked like until 1959, when a Soviet satellite photographed it and relayed pictures back.

The "old Moon in the new Moon's arms"

In the old Scottish ballad Sir Patrick Spens, a sailor cautions:

"I saw the new moon late yestreen

With the old moon in her arm;

And if we go to sea, master,

I fear we'll come to harm."

Earthshine

The effect known as "the old Moon in the new Moon's arms" can often be seen when the Moon is a narrow crescent. Within the intensely bright crescent, a dim and mysterious view of the entire circular moon is seen. The effect is also known as earthshine because it is light from the Sun reflected off the Earth to the Moon and back that lights up the darker portion of the Moon. The bright crescent is lit by the Sun and is in full daylight. The rest of the Moon is not lit by the Sun; but an astronaut standing in this area would see a "full Earth" dominating the nighttime sky, lighting it up by its earthshine. The brightness of Earthshine, and hence the visibility of the old Moon in the new Moon's arms, varies. When the Earth is covered with clouds, or when there is a lot of snow-pack on the side of the Earth facing the Moon, the Earth is a white and bright and the Earthshine is intense. When the Earth looks like a "big, blue marble," it is less intense.

Lunar calendars

Throughout history, many calendar systems have been based on the phases of the moon.

The months of the Muslim calendar are determined by observations of the hilal, the moment at which the thin crescent moon first becomes visible. This marks the start of a month. Traditionally, and today in Pakistan and Jordan, hilal is determined by actual observation and can be affected by weather and other factors. When following the traditional method, it is not actually possible to be certain precisely when future months will begin. In most Muslim countries, actual observation has been replaced by astronomical rules.

The moon in culture

"The Old Moon in the New Moon's Arms" is the title of a poem by Ella Wheeler Wilcox, in which she interprets the effect as the New Moon wishing that her lost love, the Old Moon, be in her arms one last time; Venus grants the wish, and:

Swift thro' the vapors and the golden mist—

The Full Moon's shadowy shape shone on the night,

The New Moon reached out clasping arms and kissed

Her phantom lover in the whole world's sight.

Trivia

Although the Moon is often described as revolving around the Earth, this is slightly inaccurate: the Earth and the Moon both revolve around their barycenter, their common center of mass. This point is 1,700 below the earth's surface, which is about 1/4 of the earth's radius.

The combined motion is like an athlete performing an Olympic hammer throw: one object swings in a large circle, the other almost pivots around a fixed point but actually performs a small opposing circle of its own.

When speaking of things having to do with the moon, the adjective lunar is used. The Greek-derived prefixed root selen- followed by the morpheme -o- is used as well; for example, the science of mapping the moon is called selenography (morphemes: selen-o-graph-y). (Note, however, that the apsides of the orbits of the Project Apollo spacecraft were always called pericynthion and apocynthion, not "periselene" and "aposelene.")

Other moons

While the Moon of Earth is the best-known satellite of any planet, other planets in our solar system also have moons. Earth has the least number of moons (one), while Jupiter has sixty-two. The first extraterrestrial moons to be discovered were the four Galilean moons (Io, Europa, Ganymede, and Callisto. Next to these, Earth's Moon is one of the largest, but Jupiter and Saturn have moons in orbit about them that might qualify as planets if they orbited the Sun instead.

Sizes of moons

Most moons in the solar system are no larger than typical asteroids. They are of irregular shape, have light and variable surface gravities, and are often unstable in their orbits. Phobos and Deimos, the moons of Mars, fall into this category.

Earth's own moon is an example of a dwarf planet-sized moon. These moons are so large that their own self-gravity forces them to collapse into spheres or spheroids. Some of them, like Ganymede and Titan, are larger even than the planet Mercury. Earth's moon was, of course, known to the ancients, but the remaining dwarf-planet-sized moons were generally the first to be discovered in orbit around any given primary. Galileo Galilei discovered the first four of these in orbit about Jupiter early in the seventeenth century; Christiaan Huygens then discovered Titan of Saturn later in that same century.

Symoblic Importance in Islam

The crescent moon is an internationally recognised symbol of the faith of Islam. It appears on the flags of several Islamic nations and forms part of the official emblem of the International Red Cross and Red Crescent Socoeties.

See also

• Origin of the Moon

External links

• Glossary