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5TH & 6th GRADE- SYLLABUS. 1|Page OUR SOLAR SYSTEM The Solar System is made up of the Sun and all of other smaller objects that move around it. Apart from the Sun, the largest members of the Solar System are the eight major planets. Nearest the Sun there are four fairly small, rocky planets Mercury, Venus, Earth and Mars. Beyond Mars is the asteroid belt – a region populated by millions of rocky objects. These are left-over’s from the formation of the planets, 4.5 billion years ago. On the far side of the asteroid belt are the four gas giants - Jupiter, Saturn, Uranus and Neptune. These planets are much bigger than Earth, but very lightweight for their size. They are mostly made of hydrogen and helium. Until recently, the furthest known planet was an icy world called Pluto. However, Pluto is dwarfed by Earth’s Moon and many astronomers think it is too small to be called a true planet. An object named Eris, which is at least as big as Pluto, was discovered very far from the Sun in 2005. More than 1,000 icy worlds such as Eris have been discovered beyond Pluto in recent years. These are called Kuiper Belt Objects. In 2006, the International Astronomical Union decided that Pluto and Eris must be classed as “dwarf planets”. Even further out are the comets of the Oort cloud. These are so far away that they are invisible in even the largest telescopes. Every so often one of these comets is disturbed and heads towards the Sun. It then becomes visible in the night sky. THE SUN The Sun is the most prominent feature in our solar system. It is the largest object and contains approximately 98% of the total solar system mass. One hundred and nine Earths would be required to fit across the Sun's disk, and its interior could hold over 1.3 million Earths. The Sun's outer visible layer is called the photosphere and has a 2|Page temperature of 6,000°C (11,000°F). This layer has a mottled appearance due to the turbulent eruptions of energy at the surface. What is the Sun like? The Sun is a yellow dwarf star at the center of our Solar System. All the planets of the Solar System orbit around the Sun. The Sun and the Solar System orbit around the center of our Galaxy, the Milky Way. Although the Sun is a relatively small star in the universe, it is huge in relation to our solar system. Even with massive gas planets like Jupiter and Saturn, the Sun contains 99.8% of all the mass in the solar system. The Sun is made up of superheated hydrogen and helium gas. Hydrogen makes up about 74% of the mass of the Sun. At the center of the Sun, hydrogen atoms, under intense pressure from gravity, undergo a process called nuclear fusion and get converted into helium atoms. The process of nuclear fusion generates a tremendous amount of heat causing radiation and eventually the sunlight that reaches the Earth. The Sun is the main source of energy in the Solar System and life on Earth. Plants use photosynthesis in order to harness energy from the Sun. Even energy that we get from fossil fuels like oil originally came from the Sun. We can also use solar cells to convert energy from the Sun directly into electricity. 3|Page Planet Mercury Moons: 0 Mass: 5.5% of Earth Diameter: 3031 miles What is Mercury like? Now that Pluto is no longer classified as a planet, Mercury is the smallest planet in the solar system. Mercury has a rocky surface and an iron core. The iron core in Mercury is very large compared to other rocky planets like Earth and Mars. This makes Mercury's mass very high compared to its size. Mercury is a barren planet covered with craters from impacts of asteroids and other objects. It looks very similar to the Earth's moon. Mercury has virtually no atmosphere and rotates very slowly in relationship to the sun. A single day on Mercury is as long as almost 60 Earth days. How does Mercury compare to Earth? Mercury is much smaller than Earth. It's actually a lot closer to the size of Earth's moon. It has a shorter year, but a much longer day. There is no air to breathe and the temperature changes wildly each day (even though it's a really long day!). Mercury is similar in that it has a hard rocky surface like Earth's. You could walk around on Mercury if you had a space suit and could take the extreme temperatures. 4|Page Planet Venus Moons: 0 Mass: 82% of Earth Distance from the Sun: 2nd planet from the sun, 67 million miles What is Venus like? Venus can be best described with two words: cloudy and hot. The entire surface of Venus is constantly covered by clouds. These clouds are made up mostly of carbon dioxide which has a greenhouse affect keeping in the Sun's heat like a giant blanket. As a result Venus is the hottest planet in our solar system. It is even hotter than Mercury, which is much closer to the Sun. Venus is a terrestrial planet like Mercury, Earth, and Mars. This means it has a hard rocky surface. Its geography is somewhat like Earth's geography with mountains, valleys, plateaus, and volcanoes. It is completely dry, however, and has long rivers of molten lava and thousands of volcanoes. There are over 100 giant volcanoes on Venus that are each 100km or more across. How does Venus compare to Earth? Venus is very similar to Earth in size, mass, and gravity. It is sometimes called Earth's sister planet. Of course, Venus' dense atmosphere and intense heat make Venus very different in many ways. Water, an essential part of Earth, isn't found on Venus as it all has evaporated from the heat. How do we know about Venus? Since Venus is so easily seen without a telescope there is no way to know who might have first noticed the planet. Some ancient civilizations thought it was 5|Page two planets or bright stars: a "morning star" and an "evening star". In the 6th century BC, a Greek mathematician named Pythagoras noted that it was the same planet. It was Galileo in the 1600's who figured out that Venus orbited the sun. Planet Earth Moons: 1 Diameter: 7926 miles Distance from the Sun: 3rd planet from the sun, 93 million miles We obviously know more about Earth than any of the other planets. Earth is the largest of the four terrestrial planets, the other terrestrial planets being Mercury, Venus, and Mars. By terrestrial planet we mean that Earth has a hard rocky surface. The composition of the Earth is similar to other terrestrial planets in that it has an iron-core which is surrounded by a molten mantle which, in turn, is surrounded by an outer crust. We live on top of the crust. Earth is Different There are many things that make Earth unique among the Solar System's planets. First, Earth is the only planet that we know of that contains life. Not only does earth contain life, but it supports millions of different forms of life. Another difference is that the Earth is mostly covered with water. Around 71% of the Earth is covered with salt water oceans. Earth is the only planet that has water in liquid form on it's surface. Also, the Earth's atmosphere is made up of mostly nitrogen and oxygen while Venus' and Mars' atmospheres are made up mostly of carbon dioxide. Geography of Earth 6|Page The earth has seven large land masses called continents. The continents include Africa, Asia, North America, South America, Europe, Oceania, and Antarctica. It also has 5 major bodies of water called oceans including the Atlantic, Pacific, Indian, Southern, and Arctic oceans. The highest point above sea level on Earth is Mount Everest and the lowest point is the Mariana Trench. Composition of the Earth The Earth is composed of a number of layers. On the outside is a rocky layer called the Earth's crust? Below this is the mantle followed by the outer core and the inner core. Planet Earth is made up of a number of elements. The central core of the Earth is made of mostly iron and nickel. The outer crust of the earth consists of a number of elements. The most abundant are oxygen (46%), silicon (27.7%), aluminum (8.1%), iron (5%), and calcium (3.6%). The Earth's Moon Earth has one moon or natural satellite. You've probably seen it! The Earth's moon is the fifth largest moon in the solar system. Planet Mars Moons: 2 Diameter: 4217 miles Distance from the Sun: 4th planet from the sun, 142 million miles 7|Page What is Mars like? Mars is the 4th planet from the sun. It is a terrestrial planet which means that it has a hard rocky surface that you could walk on. Mars' surface is dry and much of it is covered with a reddish dust and rocks. To us on Earth Mars appears to be the color red. Mars has some of the most impressive natural geographical structures in the Solar System. Olympus Mons, a now dormant volcano, is the highest mountain in the Solar System. It is 3 times as high as Mount Everest and towers 16 miles above the Martian surface. Another major geographical structure of Mars is the great canyon, Valleys Mariners’. This canyon is the biggest in the Solar System. It is 4 miles deep in places and stretches for thousands of miles. Weather on Mars Mars often has huge dust storms with high speed winds. These dust storms are powered by the Sun and can grow to enormous proportions sending dust miles into the atmosphere and covering much of the planet. Some storms are so big they can be seen by amateur astronomers on Earth. How does Mars compare to Earth? In many ways, Mars is very similar to Earth. Mars' year and day are very similar to Earth compared to other planets. Mars is a terrestrial planet like Earth. Mars is quite a bit smaller than Earth both in diameter and in mass. Unlike Earth, Mars has a very thin atmosphere made up mostly of carbon dioxide. As a result, it is much colder on Mars (average of -70 degrees F) than on Earth. There is evidence that open water in liquid form once existed on the surface of Mars like Earth. Perhaps there was even life on Mars billions of years ago. 8|Page How do we know about Mars? Mars is one of the easiest planets to study from Earth. It is fairly close and, since it is further from the sun than us, it is easy to view in the night sky. The Mariner 4 spacecraft was the first to bring us close up pictures of Mars in 1965. Since then several space probes have visited Mars. The Viking 1, Viking 2, and Pathfinder Landers, landed on the surface of Mars and sent us back pictures of the surface. They also analyzed the Martian soil. Mars will likely be the first planet that a human will step foot on. Many people believe it could happen by the year 2020. Planet Jupiter Moons: 63 (and growing) Diameter: 88,846 miles Distance from the Sun: 5th planet from the sun, 484 million miles What is Jupiter like? Jupiter is the largest planet in the Solar System and is the fifth planet from the sun. It is more than 300 times more massive than Earth and is more than two times more massive than all the other planets combined. Jupiter is called a gas giant planet. This is because its surface is made up of a thick layer of hydrogen gas. Deep within the planet, under the gas, the pressure becomes so intense that the hydrogen turns into liquid and then finally into a metal. Under the Hydrogen is a rocky core that is about the size of planet Earth. 9|Page Weather on Jupiter Jupiter's surface is very violent with massive hurricane-like storms, winds, thunder and lightning. One storm on Jupiter, called the Great Red Spot, is three times the size of earth. The Great Red Spot has been storming for hundreds of years. The energy powering Jupiter's storms isn't from the sun, but is from radiation generated by Jupiter itself. The Moons of Jupiter Jupiter is home to a number of interesting moons including Ganymede, Io, Europa, and Callisto. These four moons were first discovered by Galileo and are called the Galilean Moons. Ganymede, the largest moon in the Solar System, is larger than the planet Mercury. Io is covered in volcanoes and lava. Europa, on the other hand, is covered in ice and has a huge salt water sea underneath the ice. Some think there is a good possibility that life may exist in the seas of Europa. The many varying moons around Jupiter make it a fascinating place to explore. How does Jupiter compare to Earth? Jupiter is wildly different from Earth. First off, there is no place to stand, the surface is gas. Second, Jupiter is 300 times the size of earth and has (at least) 63 moons vs. Earth's one moon. Also, Jupiter has a 300 year-old storm that would swallow up the Earth without even noticing it. I'm glad we don't have any storms like that! How do we know about Jupiter? Being the 4th brightest object in the sky, humans have known of Jupiter's existence for thousands of years. Galileo first discovered Jupiter's 4 largest moons in 1610 and others claim to have discovered the Great Red Spot not long after. In 1973 the space probe Pioneer 10 flew by Jupiter and provided the first close up pictures of the planet. The Pioneer probes were followed by Voyager 1 and 2 which gave us the first close up shots of Jupiter's moons. Since then there 10 | P a g e have been many more fly-bys of Jupiter. The only spacecraft to orbit Jupiter was the Galileo in 1995. Planet Saturn Moons: 60 (and growing) Diameter: 74,900 miles Distance from the Sun: 6th planet from the sun, 887 million miles What is Saturn like? Saturn is the sixth planet from the sun. It is most famous for its beautiful giant rings. Saturn is the second largest planet in the solar system after Jupiter. It is only slightly smaller than Jupiter in diameter, but is much smaller in mass. Saturn is made up of mostly hydrogen with some helium. The surface of Saturn is gaseous, but as you go deeper the hydrogen becomes liquid and then becomes metal. Saturn's center is a hard rocky core. Overall, Saturn is the least dense planet in the solar system. It is the only planet that is less dense than water, meaning it would actually float on a (huge) ocean of water. Saturn's surface can have huge storms and contains some of the fastest winds in the Solar System of up to 1800km/h. The Rings of Saturn Saturn's rings are made up of mostly ice particles with some dust and rocks as well. There are billions of these particles and they vary in size from specs of dust to rocks as big as a bus. The rings are located around Saturn's equator. They start at about 6000km above the surface and go to 120,000km with some gaps. The rings are around 20 meters thick and can be seen from Earth with a good telescope. 11 | P a g e The Moon Titan Saturn's largest moon is Titan. Titan is the second largest moon in the Solar System after Jupiter's moon, Ganymede. Titan is the only moon in the Solar System that has a dense atmosphere. Titan's atmosphere is made up of mostly nitrogen. It was discovered by Dutch astronomer Christian Huygens in 1655. How does Saturn compare to Earth? Saturn is very different from earth. You couldn't stand on the surface of Saturn as its surface is hydrogen gas. Saturn's day of 10.7 hours is much shorter than Earth's while Saturn's year is over 29 Earth years. Saturn is also much, much bigger than Earth and Saturn has 60 moons vs. Earth's 1 moon. In addition, Saturn is unique from all the planets in the Solar system with its highly visible and gigantic rings. Planet Uranus Moons: 21 (and growing) Diameter: 31,763 miles Distance from the Sun: 7th planet from the sun, 1.8 billion miles What is Uranus like? Uranus is the 7th planet from the Sun. It is more than twice as far from the Sun as Saturn. Uranus is a gas giant like Saturn and Jupiter, but, like its sister planet Neptune, Uranus is sometimes called an ice planet. This is because much of the planet is made up of frozen elements. As a result, Uranus has the coldest atmosphere of all the planets in the Solar System. The surface of Uranus is made up of mostly hydrogen gas with some helium gas as well. The gas atmosphere makes up about 25% of the planet. This atmosphere is stormy, but not nearly as stormy or active as Saturn or Jupiter. As a result, the surface of Uranus is fairly featureless and uniform. 12 | P a g e Planet Neptune Moons: 13 (and growing) Diameter: 30,775 miles Distance from the Sun: 8th planet from the sun, 2.8 billion miles What is Neptune like? Neptune is the eighth and furthest planet from the sun. Neptune's atmosphere gives it a blue color which is fitting with it being named after the Roman god of the sea. Neptune is a gas giant, meaning that its surface is gas rather than a hard rocky surface like earth. Neptune is slightly smaller than its sister planet Uranus making it the 4th largest planet. However, Neptune is a little bit larger in mass than Uranus making it the 3rd largest planet by mass. The Atmosphere of Neptune Neptune's atmosphere is mostly made up of hydrogen with a smaller amount of helium. The surface of Neptune swirls with huge storms and powerful winds. One large storm was photographed by Voyager 2 when it passed by Neptune in 1989. It was called the Great Dark Spot. The storm was as big as the size of the Earth! The Moons of Neptune Neptune has 13 known moons. The largest of Neptune's moons is Triton. Neptune also has a small ring system similar to Saturn, but not nearly as large or as visible. How does Neptune compare to Earth? Since Neptune is a gas giant planet, there is no rocky surface to walk around on like Earth. Also, Neptune is so far away from the Sun that, unlike Earth, it gets 13 | P a g e most of its energy from its inner core rather than from the Sun. Neptune is much, much bigger than earth. Even though much of Neptune is gas, its mass is 17 times that of Earth's. Dwarf Planet Pluto Moons: 3 known Diameter: 1450 miles Distance from the Sun: 3 - 5 billion miles from the sun. What is Pluto Like? Up until 2006, Pluto was considered the 9th planet of the Solar System. At that time the IAU (International Astronomical Union) gave an official definition of a planet. Pluto no longer qualified as a planet under this definition and was reclassified as a "dwarf planet". Pluto is a relatively small planetoid, smaller than the Earth's moon. It is thought that Pluto is made up of a mantle of ice (mostly Nitrogen ice), which is about 50% of its mass, and a rocky core, which makes up the other 50% of its mass. Pluto has a unique orbit around the sun. Rather than a round or circular orbit around the sun, like the 8 planets, Pluto's orbit is more egg-shaped. At its closest point to sun, Pluto is around 2.8 billion miles away. At its furthest point, it is around 5 billion miles from the sun. When Pluto is closest to the sun, it has a thin atmosphere. As Pluto moves away from the sun, it gets so cold that the atmosphere starts to freeze and fall to the ground. Pluto has three named moons: Chiron, Nix, and Hydra. The largest is Chiron. 14 | P a g e There are two more moons that were recently discovered. Pluto and its moons are part of the Kuiper belt. Galaxies Scientists used to think that all the stars in the universe were part of one giant grouping of stars. Then, in 1917, Thomas Wright suggested that there might be lots of different large groups of stars. A few years later this was proven by other astronomers and the idea of the galaxy became real. What is a Galaxy? A galaxy is a group of stars and other space stuff. The stars tend to spin around a center of high gravity, sort of like the planets spin around the Sun in the Solar System. Galaxies are huge and can have trillions (way bigger than billions!) of stars. As big as galaxies are, they are generally separated by large areas of empty space. There are even clusters of galaxies that are separated by even larger areas of space. Scientists think there are over 100 billion galaxies. Wow, the universe is huge! Milky Way We live in the galaxy called the Milky Way. The Milky Way is part of cluster of around 3,000 galaxies called the Local Group. The Milky Way is a spiral shaped galaxy and is estimated to be made up of around 300 billion stars. 15 | P a g e The Universe What is the universe? The universe contains everything that exists including the Earth, planets, stars, space, and galaxies. This includes all matter, energy, and even time. How big is the universe? No one knows for sure just how big the universe is. It could be infinitely large. Scientists, however, measure the size of the universe by what they can see. They call this the "observable universe." The observable universe is around 93 billion light years across. The Universe is Expanding One of the interesting things about the universe is that it is currently expanding. It's growing larger and larger all the time. Not only is it growing larger, but the edge of the universe is expanding at a faster and faster rate. Scientists think that the edge of the universe is expanding faster than the speed of light. What is the universe made of? Even though the Earth seems really big to us, it's actually a very tiny part of the universe. The Sun has a mass of 330,000 times the Earth. The Sun is just one star in the Milky Way galaxy that contains over 300 billion stars and scientists estimate that there are over 170 billion galaxies in the universe! However, most of the universe is what we think of as empty space. All the stars together only make up around half a percent of the universe. The majority of the universe consists of something scientists call dark matter and dark energy. 16 | P a g e Asteroids What is an asteroid? An asteroid is a chunk of rock and metal in outer space that is in orbit around the Sun. Asteroids vary in size from just a few feet across to hundreds of miles in diameter. Most asteroids are not round, but are lumpy and shaped like a potato. As they orbit the Sun, they tumble and spin. Asteroid Belt The majority of asteroids orbit the Sun in a ring called the asteroid belt. The asteroid belt is located between the planets Mars and Jupiter. You can think of it as a belt between the rocky planets and the gas planets. There are millions and millions of asteroids in the asteroid belt. Comets and Meteors What is a comet? Comets are lumps of ice, dust, and rock that orbit the Sun. The typical comet has a core that is a few kilometers in diameter. Comets are often called the "dirty snowballs" of the Solar System. Coma and Tail As a comet nears the Sun its ices will begin to heat up and turn into gases and plasma. These gases form a large glowing "head" around the comet that is called a "coma". As the comet speeds through space, the gasses will trail behind the comet forming a tail. Because of their coma and tail, comets appear fuzzy as they near the Sun. This allows astronomers to easily determine comets from other space objects. Some comets can be seen with the naked eye as they pass by Earth. 17 | P a g e Orbit of a Comet Comets are usually divided into two groups determined by the type of orbit they have. The first type of comet is the short period comet. Short period comets have orbits of less than two hundred years. Some have very short orbits of just a few years. These types of comets originate from the Kuiper belt. The second type of comet is the long period comet. Long period comets have orbits of greater than two hundred years. Some long period comets have orbits of thousands of years. Scientists think that long period comets come from the Oort cloud. The Kuiper Belt The Kuiper belt is a region of the Solar System that lies beyond the planets and the orbit of Neptune. It is much larger than the asteroid belt. The Kuiper belt contains millions of icy objects including some larger objects like the dwarf planets Pluto and Eris. The Oort Cloud Well beyond the Kuiper belt, scientists believe there is another collection of billions of comets called the Oort cloud. This is where long orbit comets come from. The outer limit of the Oort cloud defines the outer boundary of the Solar System. What are meteoroids, meteors, and meteorites? A meteoroid is a small piece of rock or metal that has broken off from a comet or an asteroid. Meteoroids can form from asteroids colliding or as debris from comets speeding by the Sun. Meteors are meteoroids that get pulled into Earth's atmosphere by Earth's gravity. When a meteor hits the atmosphere it will heat up and burn with a bright streak of light called a "falling star" or a "shooting star." If several meteors occur at the same time and near the same place in the sky, it is called a meteor shower. A meteorite is a meteor that does not entirely burn up and makes it all the way to the ground. 18 | P a g e Lunar and Solar Eclipses What is an eclipse? An eclipse occurs when one object in space blocks an observer from seeing another object in space. From Earth there are two main types of eclipses: solar eclipses and lunar eclipses. Solar Eclipse A solar eclipse occurs when the Moon passes in front of the Sun causing a shadow to fall on certain portions of the Earth. The eclipse is not seen from every place on Earth, but only from the locations where the shadow falls. From these locations, it appears as if the Sun has gone dark. 19 | P a g e There are three main parts of the Moon's shadow during an eclipse called the umbra, penumbra, and antumbra. Umbra - The umbra is the portion of the Moon's shadow where the Moon completely covers the sun. Antumbra - The area of the shadow beyond the point of the umbra. Here the Moon is completely in front of the Sun, but doesn't cover the entire Sun. The outline of the Sun can be seen around the shadow of the Moon. Penumbra - The area of the shadow where only a portion of the Moon is in front of the Sun. Types of Solar Eclipses Depending on what part of the shadow you are located in, there are three types of eclipses: Total - A total eclipse is where the Sun is covered completely by the Moon. The portion of the Earth that is in the umbra experiences a total eclipse. Annular - An annular eclipse is when the Moon covers the Sun, but the Sun can be seen around the edges of the Moon. An annular eclipse occurs when the viewer is within the antumbra. Partial - A partial eclipse is when only a portion of the Sun is blocked by the Moon. It occurs when the observer is within the penumbra. Don't Look at A Solar Eclipse We should warn you here to never look directly at a solar eclipse. Even though it appears darker, the harmful rays of the Sun can still damage your eyes. Lunar Eclipse A lunar eclipse occurs when the Moon passes through the Earth's shadow. Lunar eclipses have the same three phases or types as solar eclipses including the umbra 20 | P a g e (total), antumbra (annular), and penumbra (partial). Lunar eclipses can be seen by a much larger area of the Earth than solar eclipses. They also can be viewed without special equipment to protect the eyes. Lunar eclipses are not totally dark. The Moon will reflect some sunlight that is refracted by the Earth's atmosphere. The light that is refracted is reddish in color and can cause the Moon to appear a dark brownish-red. **************************************************** 21 | P a g e