6 Lane Killian Caitlynn Hopper
The Moon
What it is made of The Moons is made of‌ 42% oxygen 21% silicon 13% iron 8% calcium 7% aluminum 6% magnesium 3% other elements
6 Lane Killian Caitlynn Hopper
How it was formed The moon formed between 4.0 and 4.5 billion years ago, not long after the formation of the Earth (4.5 billion years ago). There are many hypothesis and theories as to how it was made.
Fission Hypothesis There are those who believed the Earth spun so fast that a portion of its crust broke off to form the Moon. This theory is consistent with the composition of the Earth’s crust and the Moon, which both have a low density of iron. Earth has a large iron core but has a lesser concentration of iron in its crust.
Hence, if a chunk would be taken off the Earth’s crust, we would have something like the Moon. This theory however fails considerably in total angular momentum and energy analyses in connection to the Moon’s formation.
Capture Hypothesis Others once believed the Moon came from another part of the Universe with little iron, strayed near the Earth’s gravitational field, and was drawn into orbit. This, too, failed for three main reasons.
One was due to the fact that the isotope composition of Moon rocks is very similar to that of rocks from our planet. Second is the necessity for a very small (thus, highly unlikely) encounter velocity. And third, is the absence of a very thick atmosphere that should have been present to provide a so-called gas drag that would have helped in the capture process.
Co-Formation Hypothesis Still others believed that both the Moon and the Earth were formed at practically the same time and in the same region in the solar nebula, drawing materials to each other from the dust around them. While this hypothesis is consistent with the proximity of the two bodies, it is difficult to explain why they the Moon doesn’t have as much iron as the Earth.
6 Lane Killian Caitlynn Hopper
Giant Impact Hypothesis Of all four hypotheses that strive to explain the Moon’s origin, it is the Giant Impact that has received the widest acceptance. In this hypothesis, the Moon is believed to have been originally a part of the Earth’s crust, whacked out by a collision between the Earth and another body bearing the size of Mars.
Since the whacked-out piece may have certainly come from the outer layer of the Earth (the crust), then this explains the lack of iron in the Moon. Furthermore, computer simulations also show how this theory is also consistent with angular momentum measurements.
The Phases of the moon It's probably easiest to understand the moon cycle in this order: new moon and full moon, first quarter and third quarter, and the phases in between.
As shown in the diagram to the left, the new moon occurs when the moon is positioned between the earth and sun. The three objects are in approximate alignment (why "approximate" is explained below). The entire illuminated
6 Lane Killian Caitlynn Hopper portion of the moon is on the back side of the moon, the half that we cannot see.
At a full moon, the earth, moon, and sun are in approximate alignment, just as the new moon, but the moon is on the opposite side of the earth, so the entire sunlit part of the moon is facing us. The shadowed portion is entirely hidden from view.
The first quarter and third quarter moons (both often called a "half moon"), happen when the moon is at a 90 degree angle with respect to the earth and sun. So we are seeing exactly half of the moon illuminated and half in shadow.
Once you understand those four key moon phases, the phases between should be fairly easy to visualize, as the illuminated portion gradually transitions between them.
An easy way to remember and understand those "between" lunar phase names is by breaking out and defining 4 words: crescent, gibbous, waxing, and waning. The word crescent refers to the phases where the moon is less that half illuminated. The word gibbous refers to phases where the moon is more than half illuminated. Waxing essentially means "growing" or expanding in illumination, and waning means "shrinking" or decreasing in illumination.
Thus you can simply combine the two words to create the phase name, as follows:
After the new moon, the sunlit portion is increasing, but less than half, so it is waxing crescent. After the first quarter, the sunlit portion is still increasing, but now it is more than half, so it is waxing gibbous. After the full moon (maximum illumination), the light continually decreases. So the waning gibbous phase occurs next. Following the third quarter is the waning crescent, which wanes until the light is completely gone -- a new moon.
The moons orbit You may have personally observed that the moon goes through a complete moon phases cycle in about one month. That's true, but it's not exactly one month. The syndic period or lunation is exactly
6 Lane Killian Caitlynn Hopper 29.5305882 days. It's the time required for the moon to move to the same position (same phase) as seen by an observer on earth. If you were to view the moon cycling the earth from outside our solar system (the viewpoint of the stars), the time required is 27.3217 days, roughly two days less. This figure is called the sidereal period or orbital period. Why is the synodic period different from the sidereal period? The short answer is because on earth, we are viewing the moon from a moving platform: during the moon cycle, the earth has moved approximately one month along its year-long orbit around the sun, altering our angle of view with respect to the moon, and thus altering the phase. The earth's orbital direction is such that it lengthens the period for earthbound observers.
Although the synodic and sidereal periods are exact numbers, the moon phase can't be precisely calculated by simple division of days because the moon's motion (orbital speed and position) is affected and perturbed by various forces of different strengths. Hence, complex equations are used to determine the exact position and phase of the moon at any given point in time.
Also, looking at the diagram (and imagining it to scale), you may have wondered why, at a new moon, the moon doesn't block the sun, and at a full moon, why the earth doesn't block sunlight from reaching the moon. The reason is because the moon's orbit about the earth is about 5 degrees off from the earthsun orbital plane.
However, at special times during the year, the earth, moon, and sun do in fact "line up". When the moon blocks the sun or a part of it, it's called a solar eclipse, and it can only happen during the new moon phase. When the earth casts a shadow on the moon, it's called a lunar eclipse, and can only happen during the full moon phase. Roughly 4 to 7 eclipses happen in any given year, but most of them minor or "partial" eclipses. Major lunar or solar eclipses are relatively uncommon.
The moon’s effect on earth The gravitational attraction that the Moon exerts on Earth is the cause of tides in the sea. The tidal flow period is synchronized to the Moon's orbit around Earth, but the phase isn't. The tidal bulges on Earth, caused by the Moon's gravity, are carried ahead of the apparent position of the Moon by the Earth's rotation, in part because of the friction of the water as it slides over the ocean bottom and into or out of bays and estuaries. As a result, some of the Earth's rotational momentum is gradually being transferred to the Moon's orbital momentum, resulting in the Moon slowly receding from Earth at the rate of approximately 38 mm per year. At the same time the Earth's rotation is gradually slowing, the Earth's day thus lengthens by about 15 ¾s every year.
6 Lane Killian Caitlynn Hopper
The angular diameters of the Moon and the Sun as seen from Earth overlap in their variation, so that both total and annular solar eclipses are possible. In a total eclipse, the Moon completely covers the disc of the Sun and the solar corona becomes visible to the naked eye. Since the distance between the Moon and the Earth is very slightly increasing over time, the angular diameter of the Moon is decreasing. This means that several million years ago the Moon always completely covered the Sun on solar eclipses so that no annular eclipses occurred. Likewise, in several million years the Moon will no longer cover the Sun completely and no total eclipses will occur. Eclipses happen only if Sun, Earth and Moon are lined up. Solar eclipses can only occur at new moon; lunar eclipses can only occur at full moon. The Moon is most clear at night, but can sometimes be seen during the day. The Moon (and also the Sun) appear larger when close to the horizon. This is a purely psychological effect. The angular diameter of the Moon from Earth is about one half of one degree. During the brightest full moons, the Moon can have an apparent magnitude (the amount of light received from the object) of about −12.6. For comparison, the Sun has an apparent magnitude of −26.8. For any location on Earth, the highest altitude of the Moon on a day varies between the same limits as the Sun, and depends on season and lunar phase. For example, in winter the Moon comes highest when it is full, and the full moon comes highest in winter. Like the Sun, the Moon can also give rise to an optical effect known as a halo (an optical phenomenon that appears near or around a light source). The event known as a blue moon is related to the western calendar system. A blue moon is the second of two full moons to occur in the same calendar month. Blue moons occur infrequently (thus the saying once in a blue moon to denote a rare event), because the length of the calendar month in this system is close to the length of the period of the moon's phases. They are not impossible, because every month except February is longer than this period by 1 or 2 days. Blue moons occur every 2.72 years. The next blue moons will be on June 30, 2007; and December 31, 2009.*
The distance from Earth In astronomy, a lunar distance (LD) is a measurement of the distance from the Earth to the Moon. The average distance from Earth to the Moon is 384,400 kilometers (238,855 miles). The actual distance varies over the course of the orbit of the moon.
6 Lane Killian Caitlynn Hopper
Random moon Facts ■Rotation of moon The same side of the Moon always faces the Earth. The Moon's rotation period is synchronous with its revolution period around the Earth.
■Change of distance Because of a loss of orbital energy to gravity from the Earth, the Moon is very gradually moving away from the Earth. In the very early history of the Earth, the Moon looked about 3 times larger in apparent size in the sky, because it was closer to the Earth.
■Lunar atmosphere The Moon has almost no atmosphere, because of its weak gravity. All types of gas will escape from its surface. Without an atmosphere, there is no wind or water erosion. The Moon's surface is about the same now as it was 3 billion years ago. The astronauts' footprints remain unchanged on the Moon's surface. The footprints should last at least 10 million years.
■Temperatures on the moon, dress code The surface temperature fluctuates from roughly +300° F during the 2-week daytime to -270 F during the 2-week night. This is because there is not enough atmosphere to keep the Moon warm at night, nor protect it from the Sun's rays in the daytime. If you are wondering what to wear, an astronaut's suit is the most appropriate answer.
■The Apollo 11 mission to the moon
6 Lane Killian Caitlynn Hopper The Apollo 11 Saturn V space vehicle, at Launch Pad 39A, awaits the liftoff scheduled for 9:32 a.m. EDT, along with astronauts Neil A. Armstrong, Michael Collins and Edwin E. Aldrin Jr.
During the planned eight-day mission, Armstrong and Aldrin descended in a lunar module to the Moon's surface while Collins was orbiting overhead in the command module. The two astronauts spent 22 hours on the Moon, including two and one-half hours outside the lunar module. They gathered samples of lunar material and deployed scientific experiments. They rejoined Collins at the command module for the return trip to Earth.
The astronauts splashed down in the Pacific Ocean and recovery was made by the U.S.S. Hornet on July 24, 1969.
Just twenty seconds' worth of fuel remained when Apollo 11's lunar module landed on the moon.
The multi-layered space suit worn by astronauts on the Apollo moon landings weighed 180 pounds on Earth and 30 pounds on the Moon with the reduced lunar gravity. The average desktop computer contains 5-10 times more computing power than was used to land a man on the moon.
The surface speed record on the Moon is 10.56 miles per hour. It was set in an Apollo lunar rover.
â– Size comparison The volume of the Earth's moon is the same as the volume of the Pacific Ocean.
â– Lunar magnetic field The Moon has no global magnetic field. You cannot use a compass to find your direction.
6 Lane Killian Caitlynn Hopper ■Strange Mathematics: 1/2 equals 1/4 A quarter moon and a half moon are the same thing. The quarter refers to the fraction of the lunar month which has passed, whilst the half describes the portion of the Moon's disc which is visible.
■Calculation of the Easter date Easter is the first Sunday after the first Saturday after the first full moon after the equinox. (The equinox is quite often March 21, but can also occur on the March 20 or 22.)
■Tides and the moon The moon causes many of the tides in the Earth's oceans. This is because of the gravity force between the Earth and Moon. At full Moon and new Moon, the Sun, Earth and Moon are lined up, producing the higher than normal tides (called spring tides, for the way they spring up). When the Moon is at first or last quarter, smaller neap tides form.
■Sun and Moon Eclipses An eclipse of the Sun can occur only at New Moon, while an eclipse of the Moon can occur only at Full Moon. ■Moon Ingredients The moon is not made of cheese.
■Legal status - Buying land on the moon Though several flags of the United States have been symbolically planted on the moon, the U.S. government makes no claim to any part of the Moon's surface. The U.S. is party to the Outer Space Treaty, which places the Moon under the same jurisdiction as international waters. This treaty also restricts use of the Moon to peaceful purposes, explicitly banning weapons of mass destruction (including nuclear weapons) and military installations of any kind. A second treaty, the Moon Treaty, was proposed to restrict the exploitation of the Moon's resources by any single nation, but it has not been signed by any of the space-faring nations.
6 Lane Killian Caitlynn Hopper Several individuals have made claims to the Moon in whole or in part, though none of these claims are generally considered credible
The moon is not a planet, but a satellite of the Earth. The surface area of the moon is 14,658,000 square miles or 9.4 billion acres Only 59% of the moon's surface is visible from earth. The moon rotates at 10 miles per hour compared to the earth's rotation of 1000 miles per hour. When a month has two full moons, the second full moon is called a blue moon. Another definition of a blue moon is the third full moon in any season (quarter of year) containing 4 total full moons. From Earth, we always see the same side of the moon; the other side is always hidden. The dark spots we see on the moon that create the image of the man in the moon are actually craters filled with basalt, which is a very dense material. The moon is the only extraterrestrial body that has ever been visited by humans. It is also the only body that has had samples taken from it. The first space craft to send back pictures from the moon was Luna 3 (built by the Soviet Union) in October 1959. The moon has no global magnetic field. The moon is about 1/4 the size of the Earth.
Moon Geology The Moon lacks a significant atmosphere and any bodies of water, which eliminates erosion due to weather; it does not possess any form of plate tectonics, it has a lower gravity, and because of its small size, it cools more rapidly. The Moon is a differentiated body, possessing a crust, mantle and core. Geological studies of the Moon are based on a combination of Earth-based telescope, observations, measurement from orbiting spacecraft, lunar samples, and geophysical data. A few locations were sampled directly during the Apollo missions in the late 1960s and early 1970s, as well as several missions of the Soviet Luna program.