Our Solar System
Earth Science - Middle School
Our Solar System
Multimedia Lesson
Formation of Our Solar System
Presentation
The Sun
Presentation
Measuring Distances in Space
Presentation
The Inner Planets
Presentation
The Outer Planets
Presentation
Comets, Asteroids, and Meteors
Presentation
Pluto
Presentation
Planet Exploration
Virtual Lab
The Sun
Interactive
The Solar System
Interactive
Gravity and Orbits
Interactive
Our Solar System
Study Guide
Our Solar System
Quiz
Our Solar System
Quiz
Our Solar System
Flash Cards
Our Solar System
Flash Cards
Our Solar System
Worksheet
Our Solar System
Worksheet
Our Solar System
Game
Our Solar System
Game
Our Solar System
Vocabulary List
Our Solar System
Vocabulary List
Science: Earth Science
Flip Chart
Our Solar System
Flip Chart
Our Solar System
Flip Chart
Formation of Our Solar System
Flip Chart
Geocentric and Heliocentric Systems
Flip Chart
Parts of Our Solar System
Flip Chart
The Sun
Flip Chart
Measuring Distances in Space
Flip Chart
The Inner Planets
Flip Chart
The Outer Planets
Flip Chart
Comets, Asteroids and Meteors
Flip Chart
Pluto and the Kuiper Belt
Flip Chart
Our Solar System Vocabulary Review
Flip Chart
Minerals
Flip Chart
Rocks
Flip Chart
Fossils
Flip Chart
Geologic Time Scale
Flip Chart
Plate Tectonics
Flip Chart
Earthquakes
Flip Chart
Weathering of Rocks & Soil Formation
Flip Chart
Earth’s Atmosphere
Flip Chart
Understanding Weather
Flip Chart
Our Solar System
Flip Chart
Science: Earth Science
Flip Chart
Study Guide Our Solar System
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OUR SOLAR SYSTEM The Formation of Our Solar System Solar systems begin in the dust and gas clouds found in between the stars. The dust is composed of elements like iron and carbon. The gas is hydrogen and helium. These dusty clouds are called nebulae. Here these particles start to come together to form planets. NASA image of Horsehead Nebula In a nebula, dust particles collide and stick together (a process known as accretion), forming larger particles. More dust sticks to these particles and then particles begin to stick to each other. The particles grow to pebbles and to rocks and to boulders. These larger particles forming inside the nebula are far too small to be considered planets and so they are referred to as planetesimals. Close to the sun, the rocky planetesimals grew by accretion to become the rocky planets. In the outer reaches of the solar system, the gases like hydrogen and helium accreted to rocky cores forming planets called gas giants. There are no gas giants nearer the sun because it is too warm nearer the sun. The gas giant planets are massive layers of gas and frozen gas. Starting with the planet nearest the sun, the rocky planets are Mercury, Venus, Earth, and Mars. The gas giants are Jupiter, Saturn, Uranus and Neptune. Until August 24, 2006, Pluto was included in the list of gas giant planets. After much international study and debate, Pluto was removed from the list of planets and reclassified as a dwarf planet in a region of the solar system known as the Kuiper belt. The rocky planets are also referred to as the inner planets and the gas giants as the outer planets. © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.
Geocentric and Heliocentric Systems The earliest concepts about the solar system were based on observations that could be made from Earth without the aid of instruments like telescopes. Because the point of view or perspective of these early observers was from Earth itself, the solar system was described in relation to the Earth. In 140 CE, the Greek astronomer Ptolemy believed that the Earth was the center of the universe and that the sun and all other planets revolved around the Earth. This concept was believed to be true for many hundreds of years. This is the geocentric concept of the universe. Ptolemy’s universe It would not be until the mid-16th century that this concept would be challenged. In 1543, Nicolaus Copernicus published a revolutionary theory about the universe. He claimed that the sun is the center of the universe and all the planets revolve around the sun. This is the heliocentric concept of the universe (helios is the Greek word for sun). To be most accurate, Copernicus understood the sun to be the center of the universe. Though not accurate, this concept was an observation that moved our understanding closer to the truth that the sun is the center of our solar system, a collection of planets around a single star (the sun) within a galaxy called the Milky Way within a universe of galaxies. © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.
The Center of our Solar System – The Sun The sun is a burning ball of gas (mostly hydrogen and helium) that is held together by gravity. The sun is more than a mixed, uniform ball of burning gas. It has layers and structure. NASA photo of Sun The core is the center of the sun and is where the sun’s heat is produced. This heat moves from the core through the radiative zone. The radiative zone is so dense that it can literally take millions of years for light energy to move through this layer. The sun’s energy is produced by nuclear fusion reactions. In this process, hydrogen molecules undergo nuclear fusion. This creates Helium-3. Then Helium-3 molecules undergo another process of nuclear fusion. Each fusion process creates more energy. Keep in mind, the process is much more complicated than this simplified explanation. © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.
The energy produced by these fusion processes is carried toward the surface of the sun by photons (light energy). The outer layer of the sun is called the convection zone. In this layer, hot gases rise toward the surface where they cool sufficiently to descend back into the sun. This rising and falling of hotter and cooler gases produces currents near the sun’s surface. This is the same physical process responsible for convection cells in the Earth’s mantle (which drives plate tectonics) and convection cells in the atmosphere (which affect weather patterns). The surface of the sun that we are able to see is called the photosphere. Beyond the photosphere is a region just a little thicker than the diameter of the Earth called the chromosphere. “Chromosphere” literally means “color sphere” because this layer, though more transparent than the photosphere, has a reddish color. This color can be seen very briefly during a solar eclipse when the moon covers over the sun. here are cooler, dark areas on the sun’s surface called sunspots. Sunspots are the result of the sun’s magnetic field affecting the convection of heat in the sun. The sun’s magnetic field can also create solar flares. These enormous “storms” of fire on the sun’s surface can reach temperatures exceeding 5 million degrees Celsius! The outer atmosphere of the sun, the corona, extends for millions of miles beyond the sun. This atmosphere is composed of gases and can only be seen during a total solar eclipse. © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.
The Inner Planets The inner planets are also known as the terrestrial planets and as rocky planets. The terrestrial planets are Mercury, Venus, Earth and Mars. Mercury is the smallest of the terrestrial planets. Because it is closer to the sun its orbit around the sun takes only 88 Earth days. Its rotation on its axis is so slow that a single “Mercury day” is 59 Earth days long. Very little is known about Mercury. The only spacecraft to travel near Mercury was Mariner 10 in 1974 and 1975. Mariner 10 mapped less than half of Mercury’s surface. What it revealed was that Mercury is similar to our Moon in that has many craters from meteorite impacts. Mercury has no atmosphere and no moon. Since it has a magnetic field it is concluded that it has an iron core. More is known about Venus. It takes 224.7 Earth days for Venus to revolve once around the sun (its period of revolution). Venus is referred to as “Earth’s twin” or “sister planet” because they have similar compositions, gravity, and size. As viewed from above the North Pole, the Earth rotates counterclockwise. This is called prograde rotation. Venus rotates clockwise. This is called retrograde rotation. It has the densest atmosphere of the terrestrial planets, so dense in fact that a human standing on the surface would be crushed. The atmospheric pressure on Venus is 92 times that on Earth. The atmosphere on Venus consists of carbon dioxide and clouds of sulfuric acid. Venus is extensively covered with meteor impact craters and many active volcanoes (the source of the sulfur and carbon dioxide in its thick atmosphere). It is considered, geologically speaking, a young planet. The next terrestrial planet from the sun is our own, the Earth. © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.
The next beyond Earth is Mars. A number of space probes have been sent to Mars, both to study it from an orbit around the “Red Planet” and also from rovers that travel across its surface. As a result, of all the other terrestrial planets we know the most about Mars. NASA image of Mars Surface Mars has had a very active volcanic history. Unlike Earth, however, it is not tectonically active so its volcanoes are larger than any on Earth. (This planet has the largest shield volcano in the entire solar system, Olympus Mons, pictured below in NASA image.) There is growing evidence that there were, at one time, large amounts of water on Mars. There may also be a large amount of water hidden under its surface. NASA image of Mars’ Olympus Mons, a shield volcano Mars is volcanically active, but it is not tectonically active (in other words, it does not have tectonic plates that are moving relative to one another). It also has the largest canyon in the solar system, Valles Marineris. Mars has a thin atmosphere. It takes Mars approximately 2 Earth years to revolve around the sun once. A single day on Mars is only slightly longer than a day on Earth. (Astronomers call a day on Mars a sol.) Mars also has two small moons. © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.
The Outer Planets Beyond Mars are the gas giant planets. These four outer planets (Jupiter, Saturn, Uranus, and Neptune) are also referred to as the Jovian planets. The first is Jupiter (as shown in this NASA image). Jupiter is the largest planet in our solar system. The Romans named this planet after their god, Jupiter. It likely has a rocky core, but Jupiter is mostly hydrogen and helium. The rocky core is assumed since it has a magnetic field. Jupiter is marked by a giant red spot in the southern hemisphere of the planet. This red spot is an enormous storm brewing in its atmosphere. It has over 60 moons; its four most prominent moons were discovered by Galileo Galilei and are known as the Galilean Moons. The next gas giant is Saturn. It was named after the Roman god, Saturnus. Saturn is the second largest planet in the solar system. Scientists believe it actually creates more heat itself than it receives from the sun. It is composed mainly of hydrogen and helium. Winds can blow as fast as 1,800 kilometers per hour on Saturn. Saturn is most easily recognized by its dramatic rings. The rings are mostly composed of ice particles with some dust and rocky particles mixed in. Sixty moons have been identified around Saturn. © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.
Uranus is the next planet from the sun. It is visible to the naked eye, but due to its distance from the Earth (and consequently its dimness) it was not recognized as a planet until 1781. It was the first planet to be discovered with the use of a telescope. (Jupiter and Saturn, as well as the terrestrial planets are all visible to the naked eye under the right conditions – assuming you know what you are looking for!) It has layers of clouds. The atmosphere is, as with the other gas giants, hydrogen and helium. It has higher quantities of frozen ammonia, water and methane. It is therefore sometimes referred to as an “ice giant.” Its axis of rotation is horizontal, that is, in the position where the equator would be for all the other planets. It also has a magnetic field. Like the other gas giants, Uranus has a number of moons. The gas giant furthest from the sun is Neptune. Neptune is similar to Uranus in that it has a higher amount of frozen gases like methane, water and ammonia (and therefore sharing the title of “ice giant.”) It was named after the Roman sea god. It has a rock and ice core surrounded by a large layer of ices and a layer of hydrogen and helium gas. The highest wind speeds in the solar system are on Neptune. Some have been measured at up to 2,100 kilometers per hour. Until 2006, Pluto was considered the 9th planet from the sun. Intensive studies by an international group of astronomers led to the conclusion that Pluto is not a planet by the strict definition of a planet. It is therefore no longer listed as a planet but as a dwarf planet in a region of the solar system called the Kuiper Belt. Asteroids and other planetesimals left over from the formation of the solar system are found in this far distant portion of our solar system. © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.
Comets, Asteroids and Meteors Rocky bodies that circle the sun mostly in an area between Mars and Jupiter are called asteroids. This region between Mars and Jupiter is known as the asteroid belt. Asteroids are sometimes called planetesimals or small solar system bodies. Asteroids can be small or as much as nearly 100 kilometers in diameter. Meteoroids are smaller pieces of interplanetary rock that have come from asteroids. A meteorite is a meteoroid that has struck Earth. The streak of light created by a meteoroid entering Earth’s atmosphere and burning up is called a meteor. A comet is a small body composed of a mixture of rocky material and ice that orbits the sun and has a tail of ice particles trailing behind it. There are some meteorite impact craters still visible on the surface of the Earth, such as Meteor Crater in Arizona (pictured here). Though the processes of weathering, erosion and tectonics have obliterated most meteorite impact craters on Earth, some are easy to observe and others are identifiable through careful geologic study. Most geologists believe that the mass extinction of the dinosaurs was due to a massive meteorite impact. © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.
Table Of Contents: Our Solar System
1. Formation of Our Solar System
2.1. Nebulae
Solar systems begin in dusty gas clouds called nebulae that are found between stars. The dust is composed of elements like iron and carbon. Nebula gases include hydrogen and helium.
2.2. Planetesimals
Within a nebula, dust particles collide and stick together to form larger particles. This process is called accretion. The particles grow from pebbles, to rocks, to boulders. The larger particles are called planetesimals.
2.3. Rocky and Gaseous Planet Formation
Rocky planetesimals near the Sun grew by accretion to become the rocky planets—Mercury, Venus, Earth and Mars. In the colder outer parts of the solar system, frozen gases accreted to rocky cores to form the gas giant planets—Jupiter, Saturn, Uranus and Neptune.
2. Geocentric and Heliocentric Systems
3.1. Geocentric Universe Concept
Before the invention of the telescope, the solar system was described in relation to the Earth. In 140 AD, the Greek astronomer Ptolemy believed that the Earth was the center of the universe, and the Sun and planets revolved around the Earth. This is the geocentric concept of the universe.
3.2. Heliocentric Universe Concept
In 1543 Copernicus published a theory about the universe. He claimed that the Sun is the center of the universe and all the known planets revolved around the Sun. This is the heliocentric concept of the universe.
3.3. A Heliocentric Solar System
Copernicus believed that the Sun was the center of the universe. Today we know that the Sun is the center of our solar system—a collection of planets orbiting a single star, the Sun. Our solar system is within the Milky Way galaxy, which is within a universe of galaxies.
3.4. Parts of Our Solar System
Our solar system includes the Sun, eight planets, the moons of each planet and other objects that revolve around the Sun. The four rocky planets closest to the Sun are known as the inner planets, and the four gaseous planets in the outer solar system are called the outer planets. The relative size of the inner planets is much smaller than the outer planets.
3. The Sun
4.1. What Is the Sun Made of?
The Sun is a massive burning ball of gases held together by gravity. It is primarily composed of helium and hydrogen gases.
4.2. Structure of the Sun
The Sun has three main layers—the core, the radiative zone and the convective zone. The Sun’s atmosphere is made up of the photosphere, chromosphere and corona.
4.3. The Sun’s Core and Nuclear Fusion
The core at the center of the Sun produces the Sun’s heat. This energy is produced by hydrogen nuclear fusion reactions. During nuclear fusion, two or more protons fuse to form helium, and large amounts of energy are released.
4.4. The Sun’s Radiative Zone
Energy produced in the Sun’s core is carried to the Sun’s surface in the form of light energy called photons. This energy moves from the core into a very dense radiative zone. It can take thousands of years for the light energy to move through this layer and into the convective zone.
4.5. The Sun’s Convective Zone
The outer layer of the Sun is called the convective zone. Hot gases in this layer rise toward the surface, where they become cooler and denser. The gases then descend back into the Sun. This circulating movement is called convection, and is similar to currents in the Earth’s mantle.
4.6. The Sun’s Photosphere
The photosphere is the inner layer of the Sun’s atmosphere. This gaseous layer is thick enough to be visible. When we look at the Sun, we are seeing the photosphere.
4.7. The Sun’s Chromosphere
Just beyond the photosphere is a thin layer called the chromosphere, which has a reddish color. The chromosphere can be seen during a total solar eclipse when the Moon covers the Sun.
4.8. The Sun’s Corona
The outer atmosphere of the Sun is called the corona. It extends for millions of kilometers beyond the Sun, and is composed of gases. It can only be seen during a total solar eclipse.
4.9. Sunspots
Sunspots are cooler, darker areas of gas on the Sun’s surface. Cooler gases emit less light than hotter gases. These areas are caused by the Sun’s magnetic field affecting the convection heat. Scientists have discovered that the number of sunspots varies over an 11-year cycle.
4.10. Solar Flares
Solar flares are enormous areas of extreme temperature on the Sun’s surface, caused by magnetic fields. Solar flares typically occur near sunspots. When a solar flare erupts, streams of charged gas particles extend thousands of kilometers into space.
4. Pause and Interact
5.1. Review
Use the whiteboard tools to complete the activity.
5.2. The Sun
Click on the Terms button. Then click and drag each term to the correct box. Use the reset button to clear the terms and start over. Use the gear button to customize the draggable terms.
5. Measuring Distances in Space
6.1. Astronomical Units
The distance between the Earth and the Sun is approximately 150 million kilometers, or one astronomical unit (AU). Scientists use astronomical units to measure and describe distances in space. Another measurement is called a light-minute, which is the distance light travels in one minute, or approximately 18 million kilometers.
6.2. Distance Between the Planets and Sun
The dimensions of our solar system are vast. The four inner planets are much closer to the Sun than the four outer planets. There are numerous orbiting comets found beyond the planets in the outer solar system.
6. The Inner Planets
7.1. What Are the Inner Planets?
The four planets closest to the Sun, Mercury, Venus, Earth and Mars, are grouped together as the inner planets. They have rocky surfaces, and are often called the terrestrial planets. These planets are small and closely spaced, as compared to the outer planets.
7.2. Mercury
Mercury is the smallest planet, located closest to the Sun. Mercury revolves on its axis very slowly. A single Mercury day is about 59 Earth days long. Mercury does not have any moons or atmosphere. Its surface is covered with craters. A magnetic field suggests that it has an iron core.
7.3. Venus
Venus is the second closest planet to the Sun. It is often called Earth's sister or twin planet due to similar composition, gravity and size. Venus rotates very slowly in a clockwise direction, called retrograde rotation. Similar to the planet Mercury, Venus does not have any moons.
7.4. Atmosphere and Surface of Venus
Venus is surrounded by a very dense atmosphere composed of carbon dioxide and sulfuric acid clouds. Due to the greenhouse effect, Venus has the hottest surface temperature of any planet. The air pressure on Venus is 92 times that on Earth. Craters and active volcanoes cover the surface of the planet. From a geologic perspective, Venus is considered a young planet.
7.5. Earth
The Earth is the third planet from the Sun. The Earth's distance from the Sun allows for moderate temperatures that keep most surface water in liquid form. The presence of liquid water and an oxygen-rich atmosphere make Earth suitable for millions of living organisms.
7.6. Mars
Mars, the fourth planet from the Sun, has two moons. A day on Mars is slightly longer than a day on Earth, and it takes about 687 days for Mars to revolve once around the Sun. Space probes and rovers have successfully gathered much information about Mars.
7.7. Atmosphere and Surface of Mars
Mars has a very thin atmosphere composed primarily of carbon dioxide. The surface is cold, dry, and dusty, with frozen ice caps found at the poles. Landforms and rover samples indicate that in the past there were large amounts of liquid water on the surface. Mars has a volcanic history, and the largest volcano in the solar system, Olympus Mons, is found there.
7. Pause and Interact
8.1. Review
Use the whiteboard tools to complete the activity.
8. The Outer Planets
9.1. What Are the Outer Planets?
The outer planets beyond Mars are the gas giant planets, Jupiter, Saturn, Uranus and Neptune. They are also known as the Jovian planets. These planets are much larger and spaced further apart than the inner planets. They are primarily composed of hydrogen and helium.
9.2. Jupiter
Jupiter, the fifth planet from the Sun, is the largest planet in the solar system. Although primarily composed of gases, its magnetic field indicates that it may have a rocky core. It has a giant red spot that is actually an enormous storm in its atmosphere. There are 64 known moons that orbit Jupiter.
9.3. Saturn
Saturn, the sixth planet from the Sun, is the second largest planet in the solar system. Winds can blow as fast as 1,800 km on this planet. Saturn's rings are primarily composed of ice particles with some dust and rock particles mixed in. There are 62 known moons that orbit Saturn.
9.4. Uranus
Uranus, the seventh planet from the Sun, is the first planet to be discovered with the use of a telescope. Its cloudy atmosphere is primarily made of helium and hydrogen, but also has higher concentrations of frozen ammonia, water and methane. Uranus is sometimes referred to as an ice giant. This planet has two sets of rings and 27 known orbiting moons.
9.5. Rotation and Tilt of Uranus
Similar to Venus, Uranus spins on its axis in a clockwise direction, called retrograde rotation. It also has a rotation axis that is tilted almost parallel to its orbital plane. This makes it appear that Uranus is rotating on its side.
9.6. Neptune
Neptune is the furthest planet from the Sun. This gas giant is similar to Uranus in that it has a higher amount of frozen gases like methane, water and ammonia, and therefore it is also called an ice giant. The highest known wind speeds in the solar system, measuring up to 2,100 kilometers per hour, are found on Neptune. Thirteen moons orbit Neptune.
9. Pause and Interact
10.1. Review
Use the whiteboard tools to complete the activity.
10. Comets, Asteroids, and Meteors
11.1. Comets
A comet is a small body composed of rock and ice that orbits the Sun. A comet's tail of ice particles can stretch for millions of kilometers behind it. Comets originate in the outer regions of the solar system and have a wide range of orbital periods, up to a thousand years long. Scientists have identified thousands of comets, but this is just a fraction of the total number that exist.
11.2. Asteroids
Asteroids are irregularly shaped, rocky bodies that circle the Sun. They are found mostly in an area between Mars and Jupiter called the asteroid belt. Asteroids range in size from quite small to 100 kilometers in diameter. There are over 500,000 known asteroids.
11.3. Meteoroids
Meteoroids are smaller pieces of rock that have originated from asteroids. A streak of light called a meteor is seen when a meteoroid enters and burns in the Earth's atmosphere. When a meteoroid strikes Earth, it is called a meteorite. Meteor Crater in Arizona shows the impact and size of meteorite collision.
11. Pluto
12.1. Pluto and the Kuiper Belt
Up until 2006, Pluto was considered the ninth planet from the Sun. After intensive studies, a group of international astronomers concluded that Pluto was actually a dwarf planet in a region called the Kuiper Belt. Asteroids and other planetesimals are found in this far distant region of our solar system.
12. Pause and Interact
13.1. The Solar System
Click on the Terms button. Then click and drag each term to the correct box. Use the reset button to clear the terms and start over. Use the gear button to customize the draggable terms.
13. Vocabulary Review
14.1. Vocabulary Matching Review
Use the whiteboard tools to complete the activity.
14. Virtual Investigation
15.1. Planet Exploration
In this virtual investigation you will explore our solar system by comparing several characteristics of the planets. Complete the four activities and record your data during this exploration.
15. Assessment
16.1. Our Solar System
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