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Chapter 30 – vocabulary Quiz – Define terms
Craters Rays Apogee Perigee Maria 4/24/2017
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Essential Question: Compare the Galilean moons and the rings of Jupiter with the moons and rings of the other outer planets Warm Up : Explain how we ended up with our modern calendar. Exit Task: compare the rings of Jupiter to the rings of Saturn Homework Study for chapter 30 test 4/24/2017
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Vocabulary Chapter 30, define & one fact
Maria Rilles Craters Rays Apogee Perigee Eclipse Umbra Penumbra Solar eclipse Lunar eclipse New moon Waxing Full moon Waning Earthshine Calendars Day Month Solar year Julian calendar Leap year Gregorian calendar Galilean moons 4/24/2017
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List the five kinds of lunar surface features
Highlands composed of light colored rock Dark areas called Maria (dark solidified lava), that reflect little light. Rilles are areas that look like river beds where lava once flowed Craters are bowl shaped depressions, most were formed 4 billion years ago. Rays is displaced materials from more recent impacts that extend radially from the impact site. 4/24/2017
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Describe the interior of the moon
The side of the moon that faces Earth the crust is 60km thick. The side away from the Earth is up to 100km thick. Beneath the crust is the mantle, which goes to a depth of 1000 km and probably rich in silica, magnesium and iron The moon may have a small iron core with a radius less than 700 km 4/24/2017
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Summarize the four stages in the development of the moon.
The giant-impact hypothesis: says that a Mars sized object struck the earth in the early history of the solar system. Materials were ejected from this collision which formed the moon. Stage 2 The moon was covered with an ocean of molten rock. The densest sinking to the center to form the core and the lighter rock forming the crust or outer layers. 4/24/2017
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Summarize the four stages in the development of the moon.
The moon had cooled enough to form a thick crust that covered the molten rock. Debris from the formation of the solar system struck the moon producing the cratered surface. Some of the meteorites broke the crust and allowed molten rock to flow to the surface to form Maria. Stage 4 The final stage started 3 billion years ago after the moon had cooled and the debris from the early solar system had decreased. All geologic activity has stopped and meteors now cause a rayed impact. The moon has remain virtually unchanged for 3 billion years. 4/24/2017
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Describe the orbit of the moon around the earth.
The moons orbit around the earth is an ellipse. This means the distance from the earth varies when at it’s farthest point it is at apogee the closest point is perigee. The average distance is 384,000 km. The moon appears to rise and set with the earth rotation but it is really moving 1/29th the distance of it’s orbit. This can be seen in the fact that it will rise and set 50 minutes later each night. 4/24/2017
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Explain why eclipses occur.
An eclipses occurs when a planetary body passes through the shadow of another. There are two parts to the shadow the inner cone (called the umbra) blocks the sunlight completely. The outer part of the shadow (called the penumbra) only partially blocks the light. We see two types of eclipses, a lunar and a solar 4/24/2017
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Explain why eclipses occur.
Solar eclipse A solar eclipse is when the moon passes between the earth and the sun. The moons shadow fall upon the earth. People within the umbra will see a total eclipse and those in the penumbra but outside the umbra will see a partial eclipse. Because of the rotation of the earth, a total eclipse will never last more then 7 minutes. Sometimes an eclipse will occur when the moon is at it’s apogee, this is called an annular eclipse and a line of sunlight can be seen around the edge of the moon. 4/24/2017
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Explain why eclipses occur.
Lunar eclipse This occurs when the moon passes through the earth’s shadow A total eclipse occurs when the moon passes through the earth’s umbra A partial occurs when it passes through the penumbra. They last several hours. 4/24/2017
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Describe the phases of the Moon
When the moon is between the sun and earth - new moon phase. Next a waxing-crescent phase. Followed by a quarter moon Next waxing-gibbous phase full moon After this it moves into the waning-gibbous phase and when it is a quarter or less it is in the waning-crescent phase. 4/24/2017
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4/24/2017 compare the Galilean moons & the rings of Jupiter with the moons & rings of the other outer planets
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Explain How calendars are based on the movements of the Earth and the moon
People would track time passage with the phases of the moon. In time these were converted into calendars. There are three main parts days, months, and years. A day would measure the passage of one earth rotation (24 hours). A month would measure one complete moon phase (29.5 days) a year measure the time it takes the earth to complete one complete orbit around the sun ( days). 4/24/2017
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Explain How calendars are based on the movements of the Earth and the moon
Problems: a year of 365 days is too short and a 366 day is too long so there must be a way to account for the ¼ day in the year. Second a 29 day month is too short and a 30 day month is too long, the days of the month must vary to account for this problem. Third, the moon orbits the earth between 12 to 13 times in a year, so the number of months can not correspond to the movements of the earth and moon and remain accurate. 4/24/2017
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Explain How calendars are based on the movements of the Earth and the moon
The Julian calendar was the first to solve this problem. The year was divided into 12 months and eleven months had 30 or 31 days and February had 29. Later 1 day was moved to August and the leap year was added to keep the system balanced. It did not take into account for the fact that they had estimated the year 11 minutes longer then it really is. This calendar lasted over 1500 years. 4/24/2017
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Explain How calendars are based on the movements of the Earth and the moon
BY 1580 the calendar was about 10 days ahead of the seasons. To solve the problem Pope Gregory XIII ordered ten days be dropped from October in 1582 and that the Julian needed to be corrected. The solution was that every 400 years the calendar needed to be 3 days shorter, so if the leap year ends in 00 and is not divisible by 400 there is no leap and you must wait 4 years for the next leap year to occur. The Gregorian is accurate to within 26 seconds and only needs to be adjusted every 3000 years. 4/24/2017
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Compare the characteristics of the two moons of Mars
Moons of Mars: Phobos and Deimos Phobos completes an orbit in 7 hours and 40 minutes Deimos completes an orbit in about 30 hours Irregular in shape: Phobos is 27km by 19km, Deimos is 15km by 11km Phobos has an 8km crater on it, both have many craters suggesting they are old. Both are smaller then a medium sized crater on our moon 4/24/2017
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Jupiter has rings that are 6,400 km wide and less than 30 km thick
Compare the Galilean moons and the rings of Jupiter with the moons and rings of the other outer planets. Jupiter has rings that are 6,400 km wide and less than 30 km thick 4 Galilean moons; IO, Europa, Ganymede and Callisto. 4/24/2017
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All viewed by Galileo in 1610
Compare the Galilean moons and the rings of Jupiter with the moons and rings of the other outer planets. All viewed by Galileo in 1610 IO; is the closet to Jupiter, has active volcanoes of sulfur, sulfur dioxide atmosphere, giant iron core with a magnetic field and red, orange and yellow in color Europa; second closest, covered in ice 100 km thick, rock core and possible water 4/24/2017
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Compare the Galilean moons and the rings of Jupiter with the moons and rings of the other outer planets. Ganymede; third from Jupiter, low density, largest moon in the solar system, made of rock and ice, has valleys and ridges, and has a magnetic field. Callisto; farthest from Jupiter, similar to Ganymede in size, density and composition, surface is the most cratered in the solar system. 4/24/2017
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Each ring is divided into 100’s of ringlets.
Compare the Galilean moons and the rings of Jupiter with the moons and rings of the other outer planets. Saturn; Rings are larger and brighter then any other planet in solar system. Each ring is divided into 100’s of ringlets. Size of rings 64,000 km wide and 200 meters thick Has 18 moons most small and icy, has 5 large moons and Titan is largest at 5,000 km diameter. Titan has a thick nitrogen atmosphere. 4/24/2017
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Compare the Galilean moons and the rings of Jupiter with the moons and rings of the other outer planets. Uranus has 20 small moons: the four largest are Oberon, Titania, Umbriel, and Ariel – discovered in mid 1800’s. Miranda found in 1948 and the rest after 1985 by Voyager 2, Has 11 small rings Neptune has 8 moons: Triton and Nereid are largest, Triton has a retrograde orbit. Has a thin set of rings Pluto has one moon Charon and completes one orbit in 6.4 days, always over the same spot. 4/24/2017
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Jupiter number of moons 63 Saturn number of moons 60
Uranus number of moons 27 Neptune number of moons 13 Pluto number of moons 3 4/24/2017
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