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Read “ A Return to the Moon” page 659 Answer questions 1 and 2 in your journal This chapter is going to cover The major bodies in the solar system The differences between the inner and outer planets The Copernican Revolution Models of the solar system The formation of the moon In this section we will learn about: The structure of the solar system The role of gravity in planetary orbits Moon phases Lunar and solar eclipses Tides Why does the night sky look the way it does from Earth? What objects make up the solar system? How does the moon affect Earth? Vocab Planet Solar system Satellite Phase eclipse The sun, moon, and starts appear to rise and set each day because Earth spins on its axis. The stars that are visible at night change throughout the year as Earth orbits the sun. Both of these movements Affect our view of the sky The night sky will look different tonight than it will in 6 months. Star groups can move through the sky in just a few hours! The positions of object in the sky change over time because Earth, and everything else in the universe, is constantly moving. Earth’s spinning on its axis and orbiting the sun create movement in the sky. Distant objects in the sky tend to move slowly and together. Ex: stars Closer objects move across this background of stars. Ex: planets and comets Planet- a celestial body that orbits the sun is round because of its own gravity has cleared the area around its orbital path Celestial- of or relating to the sky or visible heavens. It’s an adjective Ex: sun, moon, and stars It took thousands of years for people to realize that the sun is a star. Because the sun is so close to us, the sun is the brightest object in the sky. Our atmosphere scatters the sun’s light. This blocks our view of the stars. The sun is an average star. It is not particularly hot or cold. The sun is of average size. Diameter: 1.4 million kilometers. The sun’s diameter is about 110 times Earth’s. The sun has a mass that is about 330,000 times the mass of Earth. The sun is the major external source of Heat Light As the Earth turns on its axis every 24 hours, we see the sun rise and set. Many patterns of human life, such as rising in the morning, eating meals at certain times, and sleeping at night, follow the sun’s cycle. TULIPS ARE VERY SENSATIVE TO SUNLIGHT. THEY OPEN DURING THE DAY AND CLOSE AT NIGHT. ENERGY FROM THE SUN IS ALSO THE MAIN CAUSE OF WEATHER PATTERNS AND OCEAN CURRENTS. Constellations- are groups of stars organized in recognizable patterns. Ancient Greek scholars first saw constellations and named them. They also saw the planets wander in regular paths among the stars. The ancient Greeks calculated that the stars were more distant than the planets were. After the invention of the telescope, people found other objects in the night sky.. Many faint stars Two more planets, Uranus and Neptune Several other large celestial bodies, Ceres and Pluto Solar System- is the sun and all of the objects that orbit it. The sun is the most important The sun makes up about 99% of the total mass of the solar system. The eight planets and their moons make up most of the remaining 1%. It also contain other small objects Dwarf planets, asteroids, comets, dust and gas. Every object in the solar system pulls on every other object. The greater an objects mass, the larger the gravitational force an object exerts on one another. The closer two objects are to each other, the stronger the gravitational pull is between them. The sun exerts a large force because its mass is so large. The pull of the sun keeps the Earth in its orbit. With out the sun’s pull, Earth and all of the other planets would shoot off into space. Even at great distances, the sun keeps the planets in their orbit. Gravity is also the force that keeps moons orbiting around planets. Planets can be seen because their surface or atmosphere reflect sunlight. A planet’s distance from the sun determines how long it will take the planet to orbit the sun. Mercury is the closest and it takes 88 days. Earth takes 1 year Neptune, the most distant, takes 165 years Satellite- an object in orbit around a body that has a larger mass. The moon is the Earth’s satellite because the Earth has a larger mass. The four planets closest to the sun are small and rocky and have few or no satellites. The next four are large and gaseous and have many. All of the planets in our solar system except Mercury and Venus have moons. We know of 135 natural satellites or moons orbiting planets. The smallest satellites are less them 3km in diameter. All moon are held in their orbits by the gravitational forces of their planets. Satellites also reflect sunlight so we can see them from Earth. The moon’s surface is covered with craters, caused by asteroid collisions. The maria, or large, dark patches on the moon are areas of lava that flowed out of the moon’s interior, filled the impact craters and cooled as solid rock. Like the sun, the moon affects life on Earth through its movements and gravitational influence. The moon has different phases throughout each month. The position of Earth, the sun, and the moon determines the phases of the moon. The time from one full moon to the next is 29.5 days. Many calendars have been based on the movement of the moon. When Earth, the sun, and the moon are in a straight line, observers on Earth may witness an event known as an eclipse. An eclipse occurs when one object moves into the shadow cast by another object. During a new moon, the moon may cast a shadow onto Earth. Observers within that small shadow on Earth see the sky turn dark as the moon blocks out the sun. This event is a solar eclipse. Look at Figure 9 on page 658 When the moon is full, it may pass into the shadow of the earth. All the observers on the nightside of Earth can see the full moon darken as the moon passes through Earth’s shadow. This event is called a lunar eclipse. Look at Figure 9 on page 658 Coastal areas on Earth, have two high tides and two low tides each day. This happens because the Earth rotates. Because the moon is also orbiting the Earth, the times of these tides change throughout the month. Tides are mainly a result of the gravitational influence of the moon. The sun has a minor effect. Define the 5 vocab words for Section 1 Page 653 Section 1 Review page 660 Do #1-8 You do not have to write the question Make sure you answer all parts of the question/questions. Read “Exploring Planets” page 665 Answer question 1 in your journal This section introduces the characteristics of the inner and outer planets. The important characteristics of each planet. A discussion of objects beyond the orbit of Neptune, including the Kuiper Belt. How are the inner planets similar to one another? What are gas giants? What type of bodies lie beyond the gas giants? Vocab Terrestrial planet Hydrosphere Asteroid Dwarf planet Gas giant Terrestrial Planets- are highly dense and near the sun, Mercury, Venus, Earth, and Mars. The terrestrial planets are small and have solid rocky surfaces. Scientists study these planets with telescopes, satellites, and surface probes. Inner planets have metallic cores and rocky surfaces like mountains, canyons, and craters. We did not know much about Mercury until we sent the space probe Mariner 10. Mercury is covered with craters. It is never very far from the sun. (small orbit) Mercury is 0.4 AU from the sun. astronomical unit. Surface temperature 720 K Mercury has almost no atmosphere or water. Venus is 0.7 AU from the sun. It can be seen near sun rise or sun set and is called the morning or evening star. Surface has mountains and plains. Spins slowly in an opposite direction. Venus is hot and its atmosphere contains large amounts of sulfuric acid. The CO2 in the atmosphere absorbs the radiation causing an increase in atmospheric temperature. Greater than 700K. Third planet “rock” from the sun. We measure other planets in the solar system in relation to Earth. Earth rotates on its axis in 1 Earth day. Only planet that sustains life. Only planet with lots of liquid water. Hydrosphere- all of the liquid and frozen water on Earth. Hydrosphere helps moderate the temperature of Earth. Earth’s surface does not freeze at night because of the greenhouse effect- atmosphere absorbs energy radiated by the sun. Earth’s atmosphere is composed of 78% Nitrogen 21% Oxygen 1% Carbon dioxide and other gases Debris travel through the atmosphere and heat up and vaporize or shatter before they reach Earth. Only large objects can survive the trip. Earth’s original atmosphere changed over time. Used to be more carbon dioxide, methane and ammonia The atmosphere protects us from Harmful ultraviolet radiation High energy particles from the sun Space debris No humans have visited Mars, only probes. Viking 1 and Viking 2 in 1976 In 2004, two Mars Exploration Rovers Mars has polar ice caps made of frozen carbon dioxide and frozen water. We think water used to flow across the surface as a liquid. Very thin atmosphere composed of CO2 Has 2 small satellites, Phobos and Deimos Mars is very cold, surface temperature 144-300K Martian volcano Olympus Mons- largest mountain in the solar system. Mars has low gravity, lava flows lower, larger volcanoes Many impact craters Thin atmosphere lets them in, and no water causes them to weather slowly. Mars is red because of iron oxide in its soil. Frequent dust storms that form large red dunes. Asteroids- a small rocky object that orbits the sun, most asteroids are located in a band between the orbits of Mars and Jupiter. The odds of an asteroid hitting Earth is small. The largest celestial body in the asteroid belt is Ceres. Scientists used to think it was a planet. It is a dwarf planet- a celestial body that orbits the sun, is round because of its own gravity, but has not cleared its orbital path. Asteroid Belt out side of Mars’s orbit Martian volcano Olympus Mons- largest mountain in the solar system Jupiter, Saturn, Uranus, and Neptune The outer planets are much larger than the inner planets have thick, gaseous atmospheres many satellites and rings. A spacecraft cannot land on a gas giant because it has no solid surface. The Cassini-Huygens probe reached Saturn in 2004 The rings of Saturn were discovered in 1659 Thin rings of other gas giants were found much later with modern technology. Uranus’s rings were discovered in 1977 Most of the satellites were discovered during space missions. Jupiter 60+ Saturn 40+ Uranus 27 Neptune 13 ▪ Most are cratered and have thin atmospheres First planet beyond the asteroid belt. Largest planet to orbit the sun. 1,300 times the size of Earth. It takes 12 Earth years to orbit the sun. (5 AU) Atmosphere has clouds of hydrogen, helium, methane and ammonia. (jet streams, storms) The Great Red Spot- a huge hurricane that measures more than twice the diameter of Earth. It has existed for hundreds of years. 4 Satellites- Ganymede, Callisto, Io and Europa. It takes more than 29 years to orbit the sun. A day on Saturn in 10.7 hours long It rotates faster at the equator and slower at the poles. The rings are made of dust, rock and ice. The gravitational force from Saturn and its satellites hold the particles in place. We do not know how the rings formed. Left over material when the planet formed Pieces of a smashed satellite Methane gives both planets their blue color Thick gaseous atmospheres Smaller than Jupiter and Saturn Uranus- William Hershel 1781 19AU, cold 84 years to orbit the sun Most extreme seasons because its tilted 98 degrees Neptune- Johann Galle 1846 30 AU, storms like Jupiter, cold 165 years to orbit the sun Beyond the gas giants are Numerous small bodies ▪Composed of ▪Rock ▪Ice Pluto was recorded as a planet until 2006 International Astronomical Union Met in 2006 Voted on a definition of the word planet Pluto does not clear the area around its orbital path of debris, it’s a dwarf planet. A thick gaseous atmosphere and a solid icy surface. Distance from the sun is 40AU 248 Earth days to complete one orbit Kuiper Belt- populated by many small bodies of ice and rock, like Pluto. Astronomers are actively exploring this area. Scientists have found many large bodies in this region. Eris- larger than Pluto Dwarf planet Distance from sun 90AU Section 2 Review page 670 Answer questions # 1-8 Due tomorrow! You do not have to write the question Make sure you answer all parts of the question/questions. 5 Vocab on page 661 Section 2 Review page 670 Answer questions # 1-8 Due tomorrow! You do not have to write the question Make sure you answer all parts of the question/questions. Meteor Crater is one of the youngest and bestpreserved impact craters on Earth. The crater formed roughly 50,000 years ago when a 30-meter-wide, ironrich meteor weighing 100,000 tons struck the Arizona desert at an estimated 20 kilometers per second. The resulting explosion exceeded the combined force of today's nuclear arsenals and created a 1.1kilometer-wide, 200-meter-deep crater. Read “Where are Earth’s Craters”? Page 677 Answer journal. questions 1 and 2 in your Ancient Modern models of the solar system nebular model for the solar system’s formation. Small objects in the solar system like comets, asteroids, and meteors. How the Earth’s moon was formed. How did early astronomers understand and study the solar system? Why is the solar system organized like it is? What else is the solar system besides planets? How did Earth’s moon form? How do astronomers find planets around other stars? Vocab- nebular hypothesis, nebula, comet, exoplanet Many groups of people watched the sky. Stonehenge was used to keep time. Its stones are aligned with the seasonal solstices. Ancient people used myths to explain what they did not understand. Mathematical tools began to be used to make more accurate models of observed astronomical objects. Ancient questions helped develop Science Scientific method Aristotle –Greek philosopher, explained the phases of the moon and eclipses by using a model of the solar system with Earth at the center. Geocentric or “Earth centered” Copernicus- In 1543, proposed a heliocentric model. Earth and the other planets orbit the sun in a perfect circles. Look at Figure 2 pg.672 Kepler- improved the model by figuring out that the orbits are ellipses or ovals and not circles. No one knew why planets orbited the sun in elliptical orbits until 1687. Newton- explained that gravity keeps the planets in orbit around the sun and satellites in orbit around the planets. Every object in the universe experts a gravitational force on every other object. Proposed that everything in the universe follows the same rules and acts in a predictable way. Scientists estimate that the solar system is 4.6 billion years old. Nebular hypothesis- a model for the formation of the solar system in which the sun and planets condense from a cloud or nebula of gas and dust. This hypothesis explains why objects that form from a disk will lie in the same plane have almost circular orbits Orbit in the same direction Accretion- the process by which small particles collide and stick together. Warm temperatures near the sun prevented light gases from remaining in the atmosphere of the terrestrial planets. Colder gas and dust in the outer part of the disk became the gas giants. Satellites may have formed around gas giants because of accretion. Particles could have been captured by the gravitational pull of gas giants. Small satellites could have broken off from larger ones. Most satellites orbit planets in the same direction that the planets orbit the sun. Look at Figure3 pg674. Know this figure. Comet- a small body of ice, rock, and cosmic dust that follows an elliptical orbit that gives off gas and dust in the form of a tail as it passes close to the sun. Satellites orbit planets, comets are prob. composed of material left over from the formation of the solar system. Most asteroids can be found between Mars and Jupiter. Meteorite- a meteoroid that does not completely burn up when entering the atmosphere. Comets are composed of dust and ice made from : methane, ammonia, carbon dioxide, and water. 1994- pieces of the comet Shoemaker-Levy 9 collided with Jupiter. This showed that the comet also contained: silicon, magnesium, and iron. When a comet passes the sun, it gives off gases in the form of a long tail. Some comets have two tails. An ion tail made of charged particles that is blown by the solar wind. A dust tail that follows the comet’s orbit. A comet’s orbit is very long. A comet’s tail will brighten when it passes the sun. The far-flung pieces leftover from the formation of our solar system make up the Oort cloud of comets, which may be up to 100,000 AU wide and extend in all directions. • Planetesimals that remained in the nebular disk formed the Kuiper belt beyond the orbit of Neptune. There are three major types of meteorites. Stony meteorites include carbon-rich specimens that contain organic materials and water. Metallic meteorites are made of iron and nickel. Stony-iron meteorites are a combination of the two types. Objects less than 10 m across usually burn up in Earth’s atmosphere. Meteoroids that strike Earth may leave craters. Over time, natural and manmade forces may erode craters on Earth. Some past climate events and extinctions are thought by scientists to have been caused by large meteor or comet strikes. The current theory is that the moon resulted from a collision between Earth and another large body. 1. Earth collided with a large body. The body that struck Earth may have been as large as Mars. At impact, a large part of Earth’s mantle was blasted into space. 2, The ejected material clumped together. The debris consisted of the iron core of the body, mantle material from Earth, and other material from the impacting body. 3. The moon began to orbit Earth. The moon is the only large satellite around a terrestrial planet and it is the largest moon with respect to its planet. Astronomers have discovered more than 200 exoplanets by measuring the small gravitational effects that they have on their parent star. exoplanet: a planet-like body that orbits a star other than the sun As an exoplanet orbits its star, it causes the star to wobble back and forth. Most of the newly discovered exoplanets have masses close to or larger than the masses of Jupiter or Saturn. Only a few exoplanets are in systems that have more than one discovered exoplanet. Modern detection methods favor the finding of large exoplanets, thought scientists are working on ways to detect smaller exoplanets. Chandrayaan-1 was launched successfully, without a hitch, on October 22, 2008. Chandrayaan-1 will make one complete revolution around the earth in 11 days. The Chandrayaan-1 will come into the vicinity of the moon during its second revolution around the world. The Chandrayaan-1 will map not only the surface of the moon but also what lies beneath it. ISRO will use a 3,080-pound lunar probe for creating a high-resolution map of the lunar surface and the minerals found below it. An important objective of Chandrayaan-1 is to find Helium-3 gas, a rare isotope, which could be used as a replacement for fossil fuels and also to power nuclear fusion. Section 3 Review Page 679 Answer questions #1-9 Due tomorrow You do not have to write the question Make sure you answer all parts of the question/questions. 4 Vocab words page 671 Section 3 Review Page 679 Answer questions #1-9 Due tomorrow You do not have to write the question Make sure you answer all parts of the question/questions. List the planets in order and list a distinguishing characteristic for each planet. Chapter 19 Review on page 684 Do # 1-23, 29-32 You have 5 minutes to look over your vocab.