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The Sun-Earth-Moon Relationship Earth Chapter 23, section 1 Journal Entry What are the Earth’s Movements? Objectives: Examine Earth’s physical characteristics Differentiate between rotation and revolution Discuss what causes seasons to change Homework: Complete packet #10 What are the Earth’s Motions? Earth Physical Properties of Earth Diameter (Pole to Pole) 12, 714 km Diameter (Equator) 12, 756 km Circumference (Poles) 40, 075 km Mass 5.98 X 10 to 24th power Average Density 5.52g/cm cubed Average distance to the Sun 149, 600,000 km Period of rotation 23 hours, 56 minutes Period of revolution 365 days, 6 hours, 9 minutes The Earth in Space The earth is a round three dimensional shape called a sphere. The Earth revolves around the sun. In one year it travels 940,000,000 km. The Earth rotates on its axis, an imaginary vertical line. These two combined movements affect both day and night and the seasons on Earth. Day and Night The Earth’s rotation causes day and night every 24 hours. The Earth rotates in a counterclockwise pattern ( west to east) causing the sun to appear to rise in the east and set in the west. Since the Earth’s axis is tilted when the North Pole is leaning toward the sun, the South Pole is leaning away. The hemisphere that leans toward the sun has long days and short nights. A Year on Earth The Earth takes 365.25 days to complete the revolution around the sun. An extra day is added to the calendar every four years in February. This is called a leap year. Tilt Since the earth is spherical and tilted, different areas of the earth receive different amount of sunlight. Direct and Indirect Radiation Areas near or at the equator receive direct solar radiation. As you move away from the equator, north or south, you receive less direct (indirect) radiation. Direct and Indirect The equator receives direct (90º) radiation year round. In New Jersey, we receive light that is angled about 60º (indirect). At the Poles, the light received is very indirect (30º) Indirect and Direct Radiation Direct radiation covers a smaller area and is more concentrated. The more indirect the light, the larger the area it covers and the less concentrated each area. Seasons on Earth The Earth has four seasons: winter, spring, summer and autumn. Five of the other planets, Mars, Saturn, Uranus, Neptune and possibly Pluto. The other planets, Mercury, Venus and Jupiter, do not have seasons since they are not tilted on their axis. Earth’s Orbit The earth’s orbit is an ellipse. The earth is not in the center of the ellipse. It is closest to the sun in January. It is the tilt that causes the seasons. Tilt The Earth’s tilt also causes the Sun’s radiation to strike the hemispheres at different angles. The part tilted toward receives more direct (90) angles of radiation. Seasons When the Northern Hemisphere is tilted toward the sun, that part of the Earth has summer since the sun’s rays are more direct and the days are longer. At the same time, the Southern Hemisphere is tilted away and has winter. Summer and winter are not affected by the distance from the sun. Solstices Summer begins in the Northern Hemisphere on June 20 or 21. The summer solstice is the longest day of the year. It is the time when the sun reaches its greatest distance North or South of the equator. The winter solstice is the shortest day of the year. This occurs when the Sun is directly above the Earth’s equator. When the Northern Hemisphere has the longest day, the Southern Hemisphere has the shortest day. Equinox Twice a year neither hemisphere is tilted toward the sun. These times are known as equinoxes. Spring begins on March 20 or 21, the vernal equinox. Autumn begins on September 22 or 23, the autumnal equinox. Solstice and Equinox Magnetosphere The Earth’s magnetic field is called the magnetosphere. The magnetic field starts at an altitude of 1000 km and extends to an altitude of 64,000 km on the side facing the sun. On the side facing away from the sun, the magnetosphere extends in a long tail caused by solar winds blowing away from the sun. Magnetic Field The movement of the material in the core, along with the Earth’s rotation generates a magnetic field around the earth. This field protects us from harmful radiation. Magnetic Field The magnetic field around earth also allows to know direction, and animals to migrate. Motors, computers and credit cards all work because of the magnetic field. Magnetic Field The magnetic field produces the aurora borealis and aurora australis. The location of the poles changes over times. Without the magnetosphere we would not have electricity. Magnetosphere The magnetosphere is constantly being reshaped by the solar winds. Jupiter’s Magnetosphere Jupiter’s magnetosphere is similar but much larger. The magnetic field on Jupiter is caused by a giant liquid hydrogen ocean. Journal Entry #54 What causes the phases of the moon? The Moon- Earth’s Satellite Chapter 23, section 2 Objectives: Identify the phases of the moon and their cause. Explain why solar and lunar eclipses occur. Infer what the Moon’s surface features may reveal about its history. The Moon’s Characteristics The moon’s diameter is 1/4 of the Earth. The moon’s gravity is 1/6 of the Earth. The moon is 384,403 km from the Earth. The moon does not have an atmosphere or weather. The temperature is extreme from 100 degrees Celsius to –175 degrees. Movements of the Moon Perigee is the point of the moon’s orbit closest to the Earth. The apogee is the point of the moon’s orbit farthest from the Earth. The moon’s period of rotation is the same as the period of revolution so the same side of the moon always faces the Earth. The Earth, the Moon and the Sun As the Earth moves in its yearly revolution around the sun, the moon moves in a monthly revolution around the Earth.At the same time both rotate. The motion of these three result in the changing appearance of the moon as seen from the Earth and the blocking of light. Moon At all times ½ of the moon is in darkness. We only see part of the moon from Earth. Each phase is visible at certain times of the day. Moon Phase Visibility Phase Ahead or Behind the Sun Rise time in East Mid point in sky Set time in West New Moon A few minutes behind Sunrise Noon Sunset First Quarter 6 hours behind Noon Sunset Midnight Full Moon 12 hours behind Sunset Midnight Sunrise Last Quarter 6 hours ahead Midnight Sunrise Noon Phases of the Moon The moon goes through all of its phases every 29.5 days. The moon reflects sunlight toward the Earth. The moon has 8 phases. The moon is said to be waxing when the lighted area grows larger and waning when the lighted area appears to grow smaller. Moon Phases New Moon A new moon occurs when the moon comes between the sun and Earth and the side of the moon facing Earth is in darkness. Waxing Crescent At waxing crescent phase the moon is getting larger from new moon. About ¼ of the moon is lighted on the right side. First Quarter One week later at First quarter moon, ½ of the moon appears lighted on the right side. Waxing Gibbous At this phase the part of the moon that can be seen from earth is more than ½ lighted on the right side. Full Moon At full moon the Sun earth and moon are in a direct line. The entire side of the moon that is facing the earth is completely light. Waning Gibbous The lighted part of the moon that can be seen from earth is starting to get smaller at this phase. The moon is more than ½ lighted on the left side. Last Quarter The moon is now ½ lighted on the left side. Waning Crescent The lighted part of the moon that can be seen from earth is getting smaller in this phase. It is less than ½ lighted on the left side. New Moon The moon then stars all over again as a new moon. The moon is between the earth and the sun and the side of the moon facing us is in complete darkness. Solar Eclipse A solar eclipse occurs when the new moon comes directly between the sun and the Earth. Penumbra and Umbra The people in the umbra of the shadow see a total solar eclipse. The people in the penumbra, the larger outer shadow, see a partial solar eclipse. Lunar Eclipse A lunar eclipse occurs when the moon passes through the Earth’s shadow. Lunar Eclipses When the moon moves through the umbra, a total lunar eclipse occurs. When the moon moves through the penumbra, a partial lunar eclipse occurs. Moon – Earth As a result of the Earth’s gravitational pull on the moon, the side that faces Earth has a bulge. The moon’s gravitational pull on Earth results in the rise and fall of the oceans, known as the tides. Galileo In 1609, Galileo looked at the moon with a telescope. He called the lowlands, Maria. The highlands reach to a height of 8 km. Most of the craters are in the highlands. One of the largest is Copernicus, which is 91 km in diameter. The Moon’s Surface The moon’s surface has many depressions called craters. Meteorites, asteroids and comets strike the Moon’s surface creating the depressions. Maria When the asteroids struck the surface, they caused cracks which allowed lava to flow and fill up the craters. This produced dark, flat regions called maria. Inside the Moon Scientists use instruments to study moon quakes. The crust is 60 km thick on the side facing Earth. On the far side it is 150 km thick. Inside the Moon Beyond the crust is a solid mantle that is about 1000 km deep. A partly molten zone of the mantle extends even farther down. The central core is made of solid and iron-rich. Origin of the Moon One theory states that the moon was formed millions of kilometers from the Earth and captured by its gravity. The moon may have been formed in the nebular cloud in which the Earth formed. The Impact theory says that aMars sized object struck the Earth and tore a huge chunk away, leaving a hole. Pacific Ocean The remaining depression became the Pacific Ocean. Exploring Earth’s Moon Chapter 23, Section 3 Objectives: Describe recent discoveries about the moon. Examine facts about the moon that might influence future space travel. Study of the Moon In 1959, the Soviet Union launched the Luna spacecraft which made a close up study of the moon. In 1961, the United States began a program with the first Ranger spacecraft and a series of Lunar Orbiters. Surveyor The Surveyor was designed to land on the moon. Five landed and analyzed the soil. The goal was to prepare for the landing of the Apollo astronauts. Apollo Missions In 1969 Apollo 11 landed on the moon. By 1972, then the Apollo missions ended as United States astronauts had walked on the moon. Clementine In 1994, the Clementine was placed into lunar orbit. It mapped the features of the moon, including impact basins. Impact Basins The depression left by an object striking the moon is known as an impact basin or an impact crater, The South PoleAiken Basin is the oldest identifiable feature on the moon. Frozen Water The bottom of impact basins at the poles never receive direct sunlight. The temperatures are very low. Early signals indicated the presence of frozen water that might be used for future moon colonies. Mapping the Moon The Clementine took high resolution photos of the surface. It found that the crust on the side facing Earth is much thinner than the far side. It also found that the crust is thinnest under the impact basins. Lunar Prospector In 1998, NASA launched the desksized Lunar Prospector. It orbited the moon from pole to pole for a year. Icy Poles The Lunar Prospector also mapped the Moon’s gravity, magnetic field, and abundance of 11 elements. It confirmed that 11 billion metric tons of ice water was present in deep craters at the lunar poles. Tides The rise and fall in sea level is called a tide. Tides Tides are caused by the gravitational pull of the moon and the sun. Although the sun is bigger in mass, the moon is closer, so the moon had a greater effect than the sun. High and Low Tide A rise is sea level is known as high tide A drop in sea level is known as low tide. High Tides As the earth rotates it passes under the moon. The part of the earth that is passing under the moon will have a high tide and so will the area directly on the other side of the globe. Low Tides The area in between high tide areas will have low tides. Most areas of the earth have two high tides and two low tides every day. One High and Low Tide A few areas, such as the Gulf of Mexico only have one of each. Tide Cycle A complete tide cycle of two high tides and two low tides takes 24 hours and 50 minutes. This is because the earth has to catch up to the moon since the moon moved forward while the earth was rotating. Tidal Range The tidal range is the difference between the level of the ocean at high and low tide. Tidal Bores Sometime when the tide from a wide area of ocean enters a narrow river it can make a wave in the river known as a tidal bore. Tidal Bulges Two bulges of water form, one on the side under the moon and one on the side directly opposite the moon. Tidal Bulges The force exerted by the moon on the side under the moon is greater than any other force so the water is pulled toward the moon. Tidal Bulges On the opposite side the centrifugal force of rotation is greater than any other force so the water is pulled up. Slowing Rotation The action of the tides is slowing the rotation of the Earth by 0.002 second per century. If this continues to happen we could become gravitationally locked. Sun’s Gravitational Pull The Sun’s gravitational pull can weaken or strengthen the Moon’s effect on Earth. When the moon, earth and sun are in a straight line the pull is stronger. Spring Tides Spring Tides occur during new moon and full moon. During spring tides, high tides are higher and low tides are lower than normal. There is a greater tidal range. Neap Tide Neap Tide occur when earth sun and moon are forming a right angle. The pull of the moon and sun are partially cancelled out. Neap tides are moderate. There is a small tidal range.
