PART I

INTRODUCTION

1. Background

Different moon with the sun shining and the heat emitting light, it emits light airy

and cool. This fact indicates that what is emitted by the sun and moon are not the same.

Greek scientist named Aristarchus (310-230 BC) was the first to argue with the fact that

said that the moon does not emit its own light like the sun. Months only receive sunlight

and then the beam reflected by the surface of the soil. Thus the moon is not a light source,

and the light we see it is only the reflection of sunlight. Another logic that is built to

arrive at such a conclusion is Aristarchus set of arguments moon shape that is always

changing. If the moon emits its own light, it is impossible to see it change shape. For if

the moon is a source of light across the surface will shine so wherever see the shape will

remain the same.

The lack of atmosphere on the moon cause the following things:

1. On the moon there is no life.

2. The surface is very rough month (hollow) because objects fall no hold.

3. Sound can not propagate in the month, this is because the air or gas is a medium

where the propagation of sound.

4. The sky the moon looked jet black.

Month appears to the eye as reflecting sunlight. Buntuk months seen by the earth

is always changing every day. Start of invisible, then appeared crescent and eventually

turns into a full moon on the 14th day or the 15th. Full Moon shrink back into a crescent

and lost on the 29th or 30th. Changes in the form of the moon seen from the earth is

called the phase of the moon.

The moon is a celestial body that once the satellite is closest to Earth. The moon

around the earth in the field of circulation. In the same direction with the direction of the

revolution revolution of the earth to the sun. In addition to revolve around the sun, the

moon also rotates on its axis.

To learn more about the Moon, then drafted a paper entitled "Earth-Moon

System" below.

2. Problem Formulation

From the explanation above background, it can be searched formulation of the problem is

as follows:

a. How to orbit the Moon?

b. What are the phases that occur on the Moon?

c. What is called the sidereal period and there sinodis Month?

d. What is known about the Moon's rotation?

3. Destination

From the above formulation of the problem, it can be determined the purpose of the

making of this paper is as follows:

e. Understanding the moon's orbit?

f. Understanding the phases that occur on the Moon?

g. Understanding the sidereal period and there sinodis Month?

h. Understanding the Moon's rotation?

4. Benefit

From the above formulation of the problem, it can be determined the purpose of the

making of this paper is as follows:

a. Students are able to explain the orbit of the Moon?

b. Students are able to explain the phases that occur on the Moon?

c. Students are able to explain the sidereal period and there sinodis Month?

d. Students are able to explain about the rotation of the Moon?

CHAPTER II

DISCUSSION

1. Orbit the Moon

Generally, the moon is said to orbit around the earth, but in fact the earth and

moon around the center of mass together. Because the mass of the earth is very large

compared to the moon, then the center of mass along the earth-moon system is

located about 1600 km below the Earth's surface, on the side facing the moon. The

center of mass of this joint is also called the barycenter. Because the earth rotates on

its axis, the location of the barycenter is constantly changing its position continuously

to the center of the earth.

Earth and Moon when viewed from space will appear as a double planet

system, keduaanya together (exactly on point barycenter) orbit around the sun. The

moon itself around the earth takes about 27.3 days (sidereal period). But the

circulation of the moon to the sun (period sinodis) takes up to 29.3 days. Sinodis

period is the time it takes the moon to move from one conjunction to the next

conjunction. Sinodis period can be observed with the phase of the moon changes from

a new moon, crecent, quarter, and full moon.

The moon moves around the earth in addition to (revolution), also rotates on its

axis (rotation). We always see the same surface of the moon. In the past people think this

is caused by the moon's silent, does not rotate. If so, then the surface of the moon facing

the earth is always changing and we can observe the entire side of the moon's surface.

Actually, the moon rotates with a period equal to the period of revolution around the

earth. As a result, the surface of the moon facing the earth's surface is always the same,

while the other side is always hidden from the face of the earth.

In accordance with the laws of Kepler I, basically shaped elliptical orbit of the

moon and Earth is at one focus point, but the areas of the moon's orbit is tilted about 5 ° to

the plane of the ecliptic.

Tracks this month cut the ecliptic at two points on two opposite sides of the

celestial sphere. Both of these points are called the vertices of the moon's orbit and the

line connecting the points is called a line knot. Node where the moon passes through the

ecliptic as the moon moves toward the north is called a node rises, and the node where

the moon passes through the ecliptic as the moon moves to the south is called a node

decreases.

Due to the gravitational pull of the sun's interference, then the orbit of the moon

continued to evolve, so that the node regresses around the ecliptic in 18.6 years.

Similarly, disruption of eccentricity orbits of the planets are also changing. There are two

types of months are useful for predicting eclipses, namely:

a. Draconik nodik month or months is the time interval between the two as it passes

through the same node that the length of 27.21220 days

b. Anomalistic months, an interval of two as it passes through the length perigeeyang

27 25 455 days.

But not on every new moon or full moon eclipse will occur due to the orbital

plane of the moon tilted slightly (approximately 5 °) to the plane of the ecliptic, and

therefore the new moon is usually located slightly above or below the earth's sun.

Similarly, the full moon is usually passed slightly north or south of the shadows of the

earth. The intersection of the fields of the moon's orbit with the ecliptic plane is called a

node.

The average distance from the Earth's Moon

Metric: 384 400 km

Perigee (closest)

Metric: 363 300 km

Apogee (farthest)

Metric: 405 500 km

Orbit / Month Relationship with the Earth

Ti n dal effect is

Moon's gravity pulls on Earth, causing sea level rise is known as a tidal

wave. In a much smaller extent, tides also occur in lakes, the atmosphere, and the

earth's crust. The tide on the side of the earth closest to the moon because of the

force of gravity, and also occurs on the far side of the moon because of the inertia of

the water. Pull of the moon also slows the Earth's rotation, an effect known as tidal

braking long day increase of 2.3 milliseconds per century, which means that the

moon will move away 3.8 centimeters per month year..and someday be truly free

from Earth's gravity. The gravitational pull of the moon may be the key to making

the earth a habitable planet by keeping the level of the Earth's axial tilt, which causes

a relatively stable climate over billions of years where life could develop. And you

can imagine if one day the earth did not have a satellite called the moon.

Eclipse

During the eclipse, the moon, the earth and the sun are in a straight line. A

lunar eclipse occurs when the earth will be between the sun and the moon, and the

shadow of the earth falls on the moon. A lunar eclipse can occur only during a full

moon. A solar eclipse occurs when the moon will be between the sun and Earth, and

the moon's shadow falls on the Earth. A solar eclipse can occur only during a new

moon.

Season

The earth's axis tilted with respect to the ecliptic plane, an imaginary surface

through Earth's orbit around the sun. This means the northern and southern

hemispheres will sometimes point towards or away from the sun depending on the

time of year, varying the amount of light they receive and cause the season. Earth's

axial tilt is about 23.5 degrees, but the moon's axial tilt is only about 1.5 degrees.

Thus, the moon has almost no season. This means that some areas are always

illuminated by the sun, and other places are constantly dibayangai darkness.

Exploration & Research

Moon, the brightest object in the night sky, has created a rhythm for

thousands of years. For example, one month is roughly equal to the time it takes to

go to the full moon to the next. Some ancient people believe the moon is a bowl of

fire, while others think it is a mirror that reflects the ground of the earth and the sea,

but philosophers of ancient Greece have to know the moon orbiting the Earth is a

sphere which is the reflection of light from the sun. The Greeks also believed that the

moon was dark areas of the sea, while the bright area is land. Legendary scientist

Galileo was the first to use a telescope to make scientific observations of the moon,

describing the surface, rough and filled with mountains. Contrary to popular belief in

1609 that the moon was smooth. In 1959, the Soviet Union sent the first spacecraft

successfully load the first photographs of the far side (dark) moon. In 1969, the

United States landed the first astronauts on the moon, and they returned with 382 kg

of moon rocks and soil to be studied on Earth.

2. Phase-Phase Moon

Indulge its revolution around the earth, then the position of the moon to the

earth and the sun is always changing. The moon does not emit its own light, but she

seemed to glow as the sun reflecting cahya (Nyoman Suwitra, 2001). The Moon is

Earth's closest neighbor in space. Moon is also the brightest object in the night sky,

not because it consists of a gas burning like the sun, but because the reflected light of

the sun. On some nights in the form of a perfect luminous ball, while on other nights

just a piece of silver. However, the shape and size of the moon has not changed. That

changes is penampakkannya, commensurate with the increase and decrease in the

sunlit lunar surface. The shape of the Moon different when observed from Earth

(crescent, quartiles, gibous, full moon) is called the phase of the moon.

Half Moon facing the Sun will be brighter, and the opposite half of the sun

turned dark. However, phases of the moon as seen from Earth depends on the relative

positions of the Sun, Moon, and Earth (Figure 2.1). (Anonymous,

http://www.4shared.com/office/c6tgOQBM/Tabel-Meeus-fase-bulan.html).

At position 1, the Sun, Moon, and Earth lie in one plane and the Moon

between the Earth and the sun. The position of this kind is called a conjunction. In

this position the brightest part of the Earth's moon is not visible. Month at this

position is called the new moon. At position 2, only about a quarter of the bright

parts of the Moon as seen from Earth. Month at this position is called crescent.

Threaded on until position 4 relative position of the Moon between the Earth and the

Sun indicate that the greater part. Then in the fifth position, the Sun, the Moon, and

the Earth lies in the field of the Moon is behind the Earth. Positions like this are

called the opposition. In this position throughout the bright Moon as seen from

Earth. Month at this position is at the Full Moon phase.

Months requires 29½ days to finish one orbit around the Earth. Moon walk

with the earth for the earth, orbit the sun. But when rising and sinking motion as if

from east to west, as the Earth's spin faster than the circulation of the moon around

the earth. (Anonymous, http: // nurcahyanto88. Wordpress.com/2010/06/02/fase-

fase-bulan/)

1. The occurrence of eclipse

Eclipses occur because of obstruction of sunlight. If sunlight can not reach

the Moon (in whole or in part) because it was blocked by the Earth (in other words,

the Moon is in the shadow of the Earth), then that event is called a lunar eclipse.

Meanwhile, if the shadow of the Moon falls to the surface of the Earth (the Moon

partially blocking the sun's light to the Earth), then this event now where-the solar

eclipse.

There are two kinds of shadows: umbra (shadow core) and penumbra

(shadow extra). If we are in the umbra of an object (eg umbra the Moon), the light

source (in this case the Sun) will be covered entirely by the object. Meanwhile, if we

are in the penumbra, some source of light will still be visible.

However, when the total lunar eclipse, even though the Moon is in the umbra

of the Earth, the Moon is not completely dark because some light still totally get to

the Moon's surface by atmospheric refraction effects of the earth.

The time interval required for the Earth around the Sun from the Earth-Sun

line configuration with such nodal line position A return to the original configuration

is called the eclipse. One year consists of two seasons eclipse eclipse. Since the

motion of the nodal line before, then one year of eclipse is not the same with one

sidereal year, but shorter. Sidereal year is the time interval required for the earth

around the sun.

a. Solar eclipse

1. Total solar eclipse

Solar eclipse occurs when the moon is between the earth and the sun,

which is the dead time of the month, and the shadow of the moon covering the

conical surface of the earth.

In a total solar eclipse, the entire disk of the sun covered by the moon disc.

When a total solar eclipse, the moon disc size as large or larger than the disk of

the sun. (Anonymous, http://nurcahyanto88.wordpress.com / 2010/06/02 / phases-

month /)

2. Ring solar eclipse

Ring solar eclipse is the closing event of sunlight by the moon, but the

moon does not close completely, so that the visible glow around it to resemble a

ring. (Anonymous, http://www.gung.ws/mari-melihat-gerhana-matahari-cincin/)

(sagamora bermmain friends and learning)

There is a solar eclipse ring, tip of the umbra does not reach Earth's

surface. Only extension umbra alone (called antumbra or anti umbra) that reaches

the Earth's surface. Although the entire moon is in front disc disk of the sun, but

its size is smaller than the disk of the sun, consequently the entire disk of the sun

covered. The edges of the solar disc that is not covered dish for the month, still

glowing, while the middle dark moon covered dish. Therefore eclipse solar

eclipse is called a ring.

3. Ring-Total Solar Eclipse (Solar Eclipse Hybrid)

Ring-total solar eclipse is a rare solar eclipse. In this type of solar eclipse,

in most places on Earth, the solar eclipse ring is observed, whereas in other places

the total solar eclipse.

This can happen because during the peak eclipse, the Moon is the umbra

cone peak (almost) right on the surface of the Earth, and at this location will be a

total solar eclipse is observed. While on location at the east and west of the

location before, a dark shadow that falls on the surface of the Earth is not the

umbra, but the extension of the umbra (antumbra), so for the total phase at this

location is the observed ring solar eclipse.

4. Partial solar eclipse

In the partial solar eclipse, when the peak of the eclipse occurs, the moon

does not cover the entire disk of the sun disc and not the entire disk moon is in

front of the solar disc. Also known term central eclipse and non-central eclipse.

The central eclipse is an eclipse which occurs with a line connecting the Sun-

Moon intersects the Earth's surface. If it does not cut the line connecting the

Earth's surface, the eclipse is called a non-central eclipse. The total solar eclipse,

solar eclipse ring, and the ring-total eclipse including central eclipse. While the

partial solar eclipse, there is a central one is not.

Moment of the solar eclipse in order of occurrence:

Contact I

Contact I is the current month and the disk of the sun discs are exposed.

Contact I marked the beginning of the eclipse event.

Contact II

Contacts II is the first time the entire disk of the sun covered by the moon disc

(for a total solar eclipse event), or when the entire disk of the moon is entirely

'in' disk of the sun (for solar eclipse event ring).

Contact II marked the beginning of the total phase (for a total solar eclipse), or

the phase ring (for ring solar eclipse)

The peak of the eclipse

The peak of the eclipse is when the distance between the center of the central

disk of the Moon and the Sun disc reaches a minimum.

Contact III

Contact III is the opposite Contacts II. Contact III is when the disk of the sun

started to come out from behind the moon disc (for a total solar eclipse event),

or when the disk of the moon began to leave the disk of the sun (for solar

eclipse event ring).

The interval between contacts II and III is the length of the contact phase of

total eclipse. In partial solar eclipses, phases II and contact III Contacts are not

we observe.

Contact IV

Contact IV is when the disk of the sun and moon intersect the disc when the

disc months left disk of the sun. Contact IV is the opposite of the first contact,

and marked the end of the eclipse event as a whole.

The interval between the first contact and the fourth contact is the length of a

solar eclipse event.

Based on these contact times, events solar eclipse through phases:

partial eclipse phases: interval between first contact and the second

contact, and the contact between the contacts III and IV

total eclipse phase or ring eclipse phase (depending on the total

solar eclipse or a ring): interval between contact II and contact III

Phase of the solar eclipse which was observed when the occurrence of a solar

eclipse, depending on the type of solar eclipse and where we observe. In

principle:

the total solar eclipse: eclipse phase occurs in part and the total

eclipse phase

the ring solar eclipse: eclipse phase occurs and the partial eclipse

phase ring

the partial solar eclipse: eclipse phase occurs only in part.

However, in his observations, observers in different areas will

observe different contact time, and therefore will observe the

different phases of the eclipse. It depends on the position of the

observer relative to the path through the umbra / penumbra Moon.

Therefore, to observe a solar eclipse, it needs planning and site

selection for observation.

b. Eclipse of the Moon

Lunar eclipse occurs when the earth is between the moon and the sun,

which at the time of the full moon and the shadows of the earth's surface to close

the month. Lunar eclipse can be seen clearly that the moon is covered by the

shadow of the umbra. In the circulation around the earth, there are times when the

moon moves into the region of the shadow of the umbra, so it could be more than

two hours in the dark. In such circumstances there was a total lunar eclipse.

There are times when the moon is only passing on cut umbra shadow, so

that the surface is only partially be dark. At the moment it looks like this is a

partial lunar eclipse.

Based on the current state of the peak phase of the eclipse, a lunar eclipse can

be distinguished:

1. Total Eclipse of the Moon

If the current maximum eclipse phase of the eclipse, the Moon goes into

the overall core shadow / Earth's umbra, the eclipse is called a total lunar

eclipse. The maximum total lunar eclipse of this duration can reach more than

1 hour 47 minutes.

2. Some Lunar Eclipse

If only part of the Moon to be included on the Earth umbra region, and

some are in additional shadow / penumbra of the Earth at the time of its

maximum phase, the eclipse is called partial lunar eclipse

3. Total penumbral lunar eclipse

In a lunar eclipse the 3rd kind, the month of entry into the penumbra

during the maximum phase. But no part of the Moon goes into the umbra or

not covered by the penumbra. In cases like this, we call the month eclipse

penumbral lunar eclipse is total.

4. Most penumbral lunar eclipse

And the last lunar eclipse of this kind, if only a part of the moon enters the

penumbra, the lunar eclipse is called partial penumbral lunar eclipse.

in this type of lunar eclipse, eclipse appearance almost indistinguishable

from a regular full moon.

While based on the shape, there are three types of lunar eclipses,

namely:

Type t, or a total lunar eclipse. Here, the moon entered the umbra

cone entirely into the earth.

P-type, or a partial lunar eclipse, when only a portion of a month

that goes into a cone umbrabumi.

Type pen, or penumbral lunar eclipse, when the moon entered the

penumbra cone, but no part of the moon that comes into the Earth's

umbra cone.

G

Contact times and phases of the Moon Eclipse

The moment of the eclipse the Moon sorted in order of occurrence:

P1: P1 is the first contact the penumbra, which is currently outside of the

disk of the Moon intersect the Earth's penumbra. P1 marks the start of the

lunar eclipse as a whole.

P2: P2 is a second contact penumbra, which is currently in the disk of the

Moon intersect the Earth's penumbra. When P2 occurs, the entire disk of

the Moon was in the disk of the Earth's penumbra.

U1: U1 is the first contact the umbra, which is currently outside of the

disk of the Moon intersect the Earth's umbra.

U2: U2 is the second contact umbra, which is currently in the disk of the

Moon intersect the Earth's umbra. U2 marked the beginning of the total

phase of a lunar eclipse.

Peak Eclipse

The peak of the eclipse is when the Moon disc center distance to the center

of the umbra / penumbra reaches a minimum.

U3: U3 is the third contact umbra, the Moon is when the disc back in

contact in the umbra of the Earth, when the Moon right disc will start to

leave the umbra of the Earth. U3 marking the end of the total phase of a

lunar eclipse.

U4: U4 is the fourth contact umbra, ie when the disc beyond the Moon

back in contact with the Earth's umbra.

P3: P3 is the third contact penumbral, when the Moon disc back in contact

in the penumbra of the Earth. P3 is the opposite of P2.

P4: P4 is the fourth contact penumbral, when the Moon disc back outside

contact with the Earth's penumbra. P4 is the opposite of P1, and marked

the end of a lunar eclipse events overall.

Based on these contact times, events lunar eclipse through the phases:

penumbral eclipse phase: interval between P1-U1, and the U4-P4

umbral eclipse phase: interval between U1-U4

total phase: interval between the U2-U3

Not the whole contact and the phase will occur during a lunar

eclipse. Eclipse of the moon determines the type of contacts and any

eclipse phase will occur. For example, during a total lunar eclipse, the

overall contact and the phase will pass. For a partial lunar eclipse, because

the moon is not included in the overall Earth's umbra, then U2 and U3 is

not going to happen, so that the total phase will not be observed. For a

total penumbral eclipse, because the umbra touches the Moon is not the

Earth, then U1, U2, U3, and U4 will not happen, because the umbral phase

of the eclipse will not be observed. While the partial penumbral eclipse,

only P1 and P4 are going to happen.

Unlike a solar eclipse, the lunar eclipse, contact times and the time of an

eclipse phase, is not affected by the location of the observer. All observers

are in different parts of the Earth are experiencing will observe the eclipse

contact times (umbra and penumbra) at the same time.

3. Period Sideris and Sinodis

1. Understanding the Moon as a satellite of the Earth and Moon rotation

From the results of the photographs spacecraft, moon shape faces were not

flat and smooth as seen from earth. In the form of expression consists of

mountains, craters, valleys, and sea. The moon has no atmosphere (air), so there is

no life on the moon, the temperature on the moon can be fickle, the temperature

of the surface of the moon is exposed to the sun can reach 110 C, while the parts

that are not exposed to sunlight can reach -137 C, sound can not propagate in the

moon, because there is no substance in intermediate (medium) sound propagation

is air, there is no cycle in the water, the sky looked black in the dark.

Within three months of its circulation at the same movement, the movement around its

own axis is called rotation of the moon, the movement is called a revolution

around the earth, and with the earth around the sun, the time it takes the moon to

circle the same axis with the time it takes to circle the earth. Thus, the rotation

period of months equal to the period of revolution. According to astronomers

circulation month period divided by two, the first one sidereal month period, ie the

time it takes months to get back into place. It means that the moon orbited the

Earth once, ie 27.3 days. Then there was also a period of months sinodis, ie the

time required for the appearance of a full moon to the next full moon, which is

29.5 days. One month sinodis also called Komariyah month.

2. Sideris and Sinodis Month Period

The moon around the earth in a period of perfect round (360 °) takes 27

days 7 hours 43 minutes and 11.5 seconds of the earth, exactly 27.321661 days. If

at any time the moon is at that point in the direction of certain fixed star in the

sky, then after 27 days 7 hours 43 minutes 11.51 seconds he will be back in the

same place. This period of time is called a sidereal month circulation.

Sinodis period is the time it takes the moon to look like the original. Great

period is 29.5 days. Sinodis period is defined as one month of the lunar year.

Sinodis period is the interval while it takes an object to reappear at the same point

relative to the two other objects (linear nodes), for example, when the moon

relative to the sun as seen from Earth back to the same illumination phase. Sinodis

period is elapsed time between two successive conjunctions with the Sun-Earth

line in the same linear order. Sinodis different periods of sidereal period because

the Earth orbits the sun.

As the moon orbits go through the circle, the earth and the moon as well

together around the sun ssekitar 27 ° or 1/13 trip around the sun. As a result, after

27.3 days though the moon was perfect around the earth (360 °), but at that time

not yet entered the new moon. The new moon occurs when the moon is back in

the direction of the sun (conjunction) or with other terms: earth moon and sun lie

on a straight line as shown below.

The picture above shows an illustration Circulation Sideris and Sinodis

Month. After a perfect day of the month 27.32 360 ° around the earth, the new

moon (new moon) can not occur. Still need required 2.21 more days (27 °

degrees) shift to occur conjunctions month will mark the entry of the new moon.

See the image above: Positions B1 and B3 are sinodis month period, while the B1

to B2 is the sidereal period.

For example, in the beginning the earth was in the E 1 and month in A, in

the full moon phase. After 27 day, the moon has a lap around the earth, back to its

original position on the ball during a period sederis langit.Tetapi, the earth has

been in the E 2 so that the moon is in position B. To reach the same phase (full

moon) months shall be in C, and for that it takes about 2 days, precisely in order

to achieve the position of the opposition is again time to 29 ½ days. The period

from one phase to the next phase of the same is called sinodis period.

To complete one full rotation, for example, from one full moon to the next

full 27.321661 days is not enough time. Moon still has a 27 ° again, because the

shape of the moon changes caused by the reflection of sunlight by a vision of the

earth. In other words, to achieve the full circumference of the month according to

the change of shape must cover a distance of 387 °, the distance was reached

within 29 months, 530 579 days or 29 days 12 hours 44 minutes 2.03 seconds.

Because the length of the day in accordance with the rotation of the earth

on its axis in one full rotation is 24, then the time to reach an average of 29, 530

579 days, the length specified month in the Muslim lunar months is alternated

between 29 and 30 days. With an average length of 29.5 days it was still no

difference of 0.030579 days (0 hours 44 minutes 2:03 seconds), then it is held to

cover the addition of the last day of the month of Dhu al-Hijjah ie once every 11

years in a round every 30 years. With this addition, an average month length in

29.5305 days. A figure which is quite appropriate though there is still a shortage

of about eight seconds is not influential, and therefore can be ignored.

That is why the moon appears to move east on the celestial sphere Atar

averages 13 ° each day, while the sun itself is also moving eastward from the sun

12 ° per day, and this angle is equivalent to 50 minutes. That moon appears to rise

late 50 o every day. Motion displacement of 13 ° per 24-hour mean motion about

1/2 o arc in the sky, and this distance equal to the diameter of the moon itself

moved eastward every hour. This displacement can be observed from the position

of the moon against the fixed stars in the sky every hour.

The orbit of the moon always changes gradually due to interference from

the sun's gravity. As a result, the adverse point shifted to the west along the

ecliptic and enempuh one full rotation on the celestial sphere in about 18.6 years.

This caused a lunar orbit to the ecliptic tilt varies from 4 ° 57 'and 5 ° 20 ', or the

average 5 ° 9 '. Shifting a node is called node-month regression.

Changes in the slope of the moon's orbit to the ecliptic is caused inklinas

corner, the moon's orbit to the celestial equator varies between 23 ½ + 5 ° or 28 ½ ° to 23 ½ - 5 ° or about 18 ½ o . Because the moon's orbit is actually in the form of

an ellipse, then according to Kepler's second law, the speed of the moon's orbit

also varies. Therefore, the moon eastward shift in the celestial sphere is not

uniform, so the rising of the moon each day of delay varies between 38 to 66

minutes (Nyoman Suwitra, 2001).

Typically, these are used to sinodis period as the Hijrah calendar. Hijrah

calendar is a lunar calendar Komariyah for calculating age and the month of the

calendar year is based on the circulation of the month. One month Komariyah

calculated after the phase of the moon is dead until the next dark moon phase

called sinodis period and the average duration of 29.5 days. Therefore, there is a

29-day month and some are aged 30 days. Month death itself occurs when the

moon is in the direction of the sun and is called when a conjunction.

Conjunction is an event that occurs when the angular distance (elongation)

of an object with the other object is equal to zero. In approach astronomy,

conjunction is an event when the sun and moon are aligned in the same plane of

the ecliptic. At some point, these conjunctions can cause a solar eclipse. When

conjunctions / astral conjunction is when the Moon is between the Sun-Earth,

where the moon's face becomes visible from Earth. Astronomers call the astral

conjunction or conjunctions as 'New Moon' (new moon) or also called 'the Moon

dead' because his face was not visible. In other words, conjunctions moon occurs

when the moon is new.

4. Orbit the Moon

We often see the moon surface is often changes every certain period of time.

Actually, not a month that changed the shape, but the pattern of relationships that are

formed from the position of the moon from the sun as seen from Earth that is shifted

from time to time. The impact is the change in the appearance of the moon from the

earth. The logic of the above can also be used to construct a theory that the moon

moves around the earth in its orbit. In other words, the moon does not change shape if

he does not move around the earth. Next we focus on the discussion of why the face

of the moon visible from earth only half, while the other part we've never seen from

the earth. What causes the appearance of the moon like this?

Thus the constant appearance of months due to the balance and movement of

the earth and the moon, the moon orbits the earth long circulation equal to the length

of time the moon rotates on its axis. The time required is 1 month. As a result, part of

the moon is visible from earth only to face the same side. While other parts of the

moon that never appear. To see a human face next month should go into space.

Up to this point we might ask, if the balance of the motion occurs between the

evolution of the moon and the rotation means that the surface of the moon may be

seen from the Earth is the hemisphere that is 50% of the lunar surface. Apparently

not. The movement of the moon that are not simple effects that are inconsistent with

the appearance of the above logic.

When performing motion typical month does not always lie in the same plane.

Either shape or position relative to the sun and the earth is continuously changing.

Because of this it causes the visible part of the moon on the earth is somewhat

different so that after a period of time (ie one month) we can see 59% of the lunar

surface from an observation point on earth. Changes in the moon's orbit occur in the

life-d aur. The sides of the disc on the north and south poles and the right part can be

alternated left visible.

We always see the same surface of the moon, the surface always showed the

characteristics of a grandmother who was weaving. So for centuries humans do not know

how the image of the back of the moon. Only in 1956 when the Russian spacecraft Luna

2, managed to create an image of the back of the photos of the month.

The surface of the moon facing the earth's surface is always the same, is due a

month apart evolved around the earth, the moon also perform rotational motion about

an axis with a rotation period equal to the period of revolution.

But if you look carefully, to a certain observers on Earth, the moon does not

always reveal the exact same surface, but less 50% for the period. The motion of the

earth and the moon causes at different times we can see the surface of the moon is a little

different and this trail is called libration.

Libration was first observed by the Italian scientist, Galileo Galilei made his own

telescope. There are three types of libration, which is geometric ie libration in

longitude, the latitude libration, and diurnal libration.

1. Libras i on longitude

Is a result of the motion of the moon in the form of an ellipse evolution so

varied angular velocity or speed of the movement of the moon around the earth is not

fixed. Sometimes fast sometimes slow. This led us to look a little on the west side and

then a little on the west side and then the next bit of the east side, and each of them in a

span of nearly 8 o . Whereas the rotational motion is always fixed. This effect is visible

surface of the moon from the earth shifted in the direction of east and west, or libration

in longitude. Motion as if this is simulated as if months of shaking left and right

motion.

2. Libration in latitude

Is due to the motion of the moon nods. The axis of rotation of the moon is not

exactly perpendicular to its orbital plane, but tilted at an angle of 6.5 ° . As a result we

see the moon approximately 6.5 ° outside the north pole, and two weeks later we saw a

6.5 ° outside the south pole. The effect is a small area at the poles of the moon visible

from earth alternately after a month traveling around half of its trajectory. Or the

center point of the sphere months seem to shift up and down. To better understand the

motion of the moon so we need to remember that the moon is elliptical trajectory. At

any given time the moon is at its closest to Earth, at a time when others are within a

month farther from the earth. Just as the earth is elliptical trajectory of the sun. The

trajectory ellipse & nbsp; this makes the sun-earth distance and distance of & nbsp; the

moon-earth changes periodically. In these cases the applicable law and the Law of

Gravity Keppler II that took effect on acceleration and deceleration falling circular

motion.

3. Libration diurnal

Is due to the rotation of the earth so that the surface of the moon that we see at

sunrise shifted about 1 ° to the east edge of the month when we see the time will be set.

Libration is caused by the position of the different observations of people who watched

the moon on the earth. Observer A will see the moon at the center point of a point,

whereas observer B will see the moon at the center point b. Since the distance between

the earth on the moon is not much which is about 385,000 miles, the difference seems

to be very clear. There are certain parts of the moon that can not be seen by a look by

B, otherwise there is a part that is not visible to the moon can be seen by B of A.

The influence of these three types of libration causes the moon's surface is

visible from Earth to more than half. Exact figures can not be obtained just by simple

observation and cursory. Research and measurement must be done carefully. But if

roughly estimated approximately as follows: Part-looking and always facing the Earth

3/7; part of the earth never looked 3/7 and Part-looking because of the libration is 1/7.

Then the surface of the moon that can be seen from the earth is about 4/7 or more parts

of the half. Or a long time interval we can see about 60% of the surface of the moon is

actually hidden is about 40% and that always seems about 10% and 20% variable.

CHAPTER III

CLOSING

1. Conclusion

From the above discussion, it can be disumpulkan:

The moon moves around the earth in addition to (revolution), also rotates on its axis

(rotation).

Tracks months cut the ecliptic at two points on opposite sides in the celestial sphere.

There are two types of months are useful for predicting eclipses, namely:

a. Month nodik or months draconik ie the interval between the two as it passes

through the same node that the length of 27.21220 days

b. Month anomalistic , an interval of two as it passes through the length perigeeyang

27 25 455 days.

The shape of the Moon different when observed from Earth (crescent, quartiles, gibous,

full moon) is called the phase of the moon.

Eclipses occur because of obstruction of sunlight.

There are two kinds of shadows: umbra (shadow core) and penumbra (shadow extra).

According to astronomers circulation month period divided by two, the first one sidereal

month period, ie the time it takes months to get back into place. It means that the moon

orbited the Earth once, at 27, 3 days. Then there was also a period of months sinodis, ie

the time required for the appearance of a full moon to the next full moon, which is 29, 5

days.

One month is called the month sinodis Komariyah

Conjunction is an event that occurs when the angular distance (elongation) of an object

with the other object is equal to zero.

The motion of the earth and the moon causes at different times we can see the surface of

the moon is a little different and this trail is called libration.

Libration was first observed by the Italian scientist, Galileo Galilei made his own

telescope. There are three types of libration, which is geometric ie libration in longitude,

the latitude libration, and diurnal libration.

3.2 Advice

As for the suggestion that the authors give to the reader that in order to understand the

material so that the dynamic power can be applied to everyday life, so it can be beneficial.

Basic Physics 6 Earth-Moon System