The moon and tides

THE MOON AND TIDES

The Moon The moon is probably the most

familiar object in the night sky. Like the planets, it shines because it reflects light from the sun. It is also the “fossils” of a planet’s past. However, the moon does not orbit the sun directly. It orbits our own planet Earth at a distance of 385,000 km. The surface of the moon is covered with crates, mostly caused by asteroids crashing into the moon early in the history of the solar system. Large dark patches on the moon’s surface are seas of lava that flowed out of the moon’s interior.

The Phases of the Moon

As the moon orbits Earth’ it appears to have different shapes. These are called phases. The phases of the moon are determined by the relative positions of the Earth, moon and the sun. At any time, the sun illuminates half the moon’s surface, just as at any time it is daytime on one half of Earth, and nighttime on the other half. The observed time from one full moon is 29.5 days.

Micro Moons What is a Micro Moon? Contrary to the popular belief,

the moon orbits the Earth in an elliptical path, with one side of the path closer to the Earth than the other. The point closest to the earth is called the perigee, while the point farthest to the earth is called the apogee. The average distance between the two extreme points is 237,700 miles or 382,500 km. When a full moon coincides with the moon’s position at apogee, it is referred to as Micro Moon or Mini Moon. Sometimes also called an Apogee Moon, a Micro Moon looks approximately 14 percent smaller, and around 30 percent less bright than a Super Moon. The last Micro Full Moon was on January 16, 2014.

What happens if a full moon happens at perigee?

There are no universal rules as to how far away the Moon must be to qualify as a Micro Moon. The definitions are:

If it is further away than 400,000 kilometers at apogee, it is listed as a Micro Moon.

If a full moon is closer than 360,000 kilometers at perigee, it is considered a Super Full Moon.

Super Moon

What is a Super Full Moon? The distance of the moon from the Earth varies throughout the month and

year. The average distance is about 238,000 miles (382,900 kilometers). The moon's position furthest away from Earth is called “apogee” while its closest approach to Earth is referred to as “perigee”. These events do not regularly coincide with the  phases of the moon. However, it can happen that the moon is at perigee during the phase of full moon. This event is referred to as Super Full Moon.

What happens if a full moon occurs at apogee?

There are no universal rules as to how close the moon must be to qualify as a Super Full Moon. The definitions are:

If a full moon is closer than 360,000 kilometers at perigee, it is considered a Super Full Moon.

If it is further away than 400,000 kilometers at apogee, it is listed as a Micro Moon.

Blue Moon A year has four seasons - Spring,

Summer, Fall, and Winter - with three months and three full moons each. When one of the seasons in a year has four full moons, instead of the usual three, the third full moon is called a blue moon. The last blue moon will occur on 21 August, 2013.

These days, the second full moon in a calendar month is also often referred to as a blue moon. This particular use was popularized due to a misinterpretation in a 1946 article in Sky and Telescope magazine. Such blue moons occur rather frequently - at least once every two or three years.

Rare phenomenon Blue colored moons do rarely occur when

dust or smoke particles in the air are of a specific size. Such particles help create a blue colored moon by scattering blue light.

Red moons, which can be caused by other sizes of dust particles or lunar eclipses , are much more common than blue moons.

The phrase, once in a blue moon, is colloquially used to suggest that something is very rare.

Why the third Moon? There are different accounts of why the third

full moon of a season of four full moons is called a blue moon.

For instance, the Ecclestical calendar, which indicates the dates of the Christian fasts and festivals, uses the phases of the moon to determine the exact dates for holidays like Lent and Easter. The month of Lent contains the Lenten Moon. The first full moon of Spring – also known as Easter Moon or Paschal Moon – falls a week before Easter. In order to ensure that Lent and Easter coincides with the phases of the moon, the calendar has termed the third moon of the season as the blue moon.

Other accounts suggest that since each full moon of a normal year had a corresponding name, for instance Harvest Moon, the 13th moon in a year was called a blue moon. This way the calendar was aligned to make sure celebrations and holidays would still fall during their "proper" times.

Did you know that? About once every 19 years, the month of

February does not have a full moon. The years when this happens, also have two full moons in two different months. This phenomenon will occur next in 2018?

Blood Moons Blood Moons happen

when the moon will be red in color because of the light coming from the sun. Blood Moons are rare. When four blood moons happens consecutively it is already called a tetrad. Every time a blood moon pattern has appeared on Jewish feast days a big event affects the nation of Israel. The event affecting Israel begins just before the actual years of the blood moons. To understand what will happen in the 2014 - 2015 "blood moons" you must understand the pattern of blood moons in the past.

Eclipses An eclipse is an astronomical

event that occurs when an astronomical object is temporarily obscured, either by passing into the shadow of another body or by having another body pass between it and the viewer. An eclipse occurs when one object moves into the shadow cast by another object. While exploring Jamaica in 1504, Christopher Columbus impressed the natives by predicting an eclipse. Eclipses can be predicted because they happen only when Earth, the sun and moon are in a straight line. There are 2 types of eclipse: the solar eclipse and the lunar eclipse.

Solar Eclipses During a new moon, the moon

may cast a shadow onto Earth. Observers within that shadow on Earth see the sky turn dark as the moon blocks out the sun. This is called solar eclipse. As observed from the Earth, a solar eclipse occurs when the Moon passes in front of the Sun. The type of solar eclipse event depends on the distance of the Moon from the Earth during the event. A total solar eclipse occurs when the Earth intersects the umbra portion of the Moon's shadow. When the umbra does not reach the surface of the Earth, the Sun is only partially occulted, resulting in an annular eclipse. Partial solar eclipses occur when the viewer is inside the penumbra.

Lunar Eclipses When the moon is full, it

may pass into the shadow of Earth. Observers on Earth can see the full moon become temporarily dark as it passes through Earth’s shadow. This is called a lunar eclipse. Lunar eclipses occur when the Moon passes through the Earth's shadow. This occurs only when the Moon is on the far side of the Earth from the Sun, lunar eclipses only occur when there is a full moon. Unlike a solar eclipse, an eclipse of the Moon can be observed from nearly an entire hemisphere. For this reason it is much more common to observe a lunar eclipse from a given location. A lunar eclipse also lasts longer, taking several hours to complete, with totality itself usually averaging anywhere from about 30 minutes to over an hour.

3 types of Lunar Eclipse

There are three types of lunar eclipses: Penumbral-when the Moon crosses only

the Earth's penumbra Partial-when the Moon crosses partially

into the Earth's umbra. Total-when the Moon crosses entirely into

the Earth's umbra

The Umbra and Penumbra

What is the Umbra? The umbra are places that receive the

darker side of the shadow of the eclipse. The observers in the umbra may experience a total solar eclipse.

What is the Penumbra? The penumbra are places which receive

the lighter side of the shadow of the eclipse. The places in the penumbra side have the partial eclipse.

Tides The chief and most observable effect of the

moon on Earth is the occurrence of tides. Tides pertain to the regular rise and fall in the in the region of the ocean water. The Earth and the moon exert mutual gravitational pull. Without the strong gravitational pull of Earth. It may be elsewhere in our solar system. On the other hand, Earth is also affected by the moon’s gravitational pull. On the side of the earth where the moon is, the moon’s gravity causes a bulge on the solid part of the earth to form. The bulge is only very slight, about a few inches at most.

However, the bulge becomes pulled away observable because the water in the ocean is free to move. It behaves as if it is being pulled away from the earth in response to the gravitational pull of the moon. Thus when the level of the water rises in the region where the moon is rising, a high tide occurs. At the same time, a similar high tide occurs on the other side of the earth. Because the moon’s pull is less on this side, the solid portion of the earth tends to be thrown off into space by Earth’s rotation and revolution. Another bulge in this area occurs which also causes the rise in the level of the water. The bulge on the side facing the moon is called direct tidal bulge, while the one on the other side is called opposite tidal bulge. The earth’s rotation causes the formation of two high tides and two low tides each day.

Examples of High Tides and Low Tides

2 types of Tides

There are two types of tides: the Spring Tides the Neap Tides

Spring Tides Twice each month,

the high and low tides are respectively higher and lower than usual. This occurs during new moon and full moon. At such times, the Earth, sun, and the moon fall in line. The gravitational pull of the sun, although weaker than that of the moon because of it’s great distance, also causes the formation of bulges on Earth. As a result, the tidal effect of the moon and sun are added together. Tides produced in this case are called spring tides.

Neap Tides

Twice a month also, the high tides are lower than usual, and the low tides are higher than usual. This happens during the first and last quarter phases of the moon. The sun, Earth, and moon are at a right angle with each other. The gravitational pulls of the sun and moon tend to cancel each other. The tides produced in this case are called neap tides.

My 10 Questiions 1.What is the micro moon? 2. Enumerate the 2 types of tides. 3. Enumerate the 3 types of lunar eclipse. 4.When does eclipses happen? 5.What are neap tides? 6.What is a Tetrad? True or False __7.The chief and most observable effect of the

moon on Earth is the occurrence of tides. __8. The observers in the penumbra may

experience a total solar eclipse. __9. The umbra are places which receive the lighter

side of the shadow of the eclipse. __10. There are three types of tides.

Answers 1.It is when the moon is at its farthest point. 2. spring tides and neap tides 3. penumbral, partial and total 4.it happens when the sun, moon and Earth

are in a straight line 5.When the the high tides are lower than

usual, and the low tides are higher than usual.

6. When four blood moons happens consecutively

7.True 8.False 9.False 10.False

Science 5

Nicole Cammylle A. Beltran 5-Sapphire SY2013-2014 T.Myleen Caguimdagan