Welcome to Astronomy! FIND YOUR SEAT!! 8/30/2012 DMA 3 x 5 card directions On one side of the card, you will write 4 things about yourself: 1 . One thing you have in common with everyone in the class (ex: I am a Kentridge student). 2. One thing you have in common with about half of the class (ex: I am a boy or I am a girl) 3. One thing you have in common with 3 -4 people in this class (ex: I like to snow board). 4. One thing unique to you! (ex: My birthday is tomorrow). MY ANSWERS! 1. One thing you have in common with everyone in the class I live in Washington. 2. One thing you have in common with about half of the class I have a dog and a cat. 3. One thing you have in common with 3-4 people in this class I have snorkeled in Hanauma Bay, Hawaii 4. One thing unique to you! I have held a lemur. 3 X 5 DIRECTIONS: PART 2 On the other side of your card, answer these questions: 1) What has been your favorite school subject so far? 2) What has been your least favorite school subject so far? 3) What is one thing that you like to do outside of school in your spare time? 4) What is one extracurricular school sport, club, or activity that you are participating in currently or are interested in participating in this school year? WHAT YOU WILL LEARN IN ASTRONOMY Identify and describe the unique criteria for life. Describe how Earth is unique, among other solar bodies. Understand how social and technological development contributes to new discoveries. Describe the factors that contribute to scientific revolution in the area of astronomy. Understand how technology improves one’s ability to better study the universe. WHAT YOU WILL LEARN IN ASTRONOMY Apply data and evaluate varying models of solar system patterns of movement. Understand what accounts for dif ferences among established groups of planets. Identify and explain the limits of human space exploration and travel. Predict the impact of space exploration on Earth and its inhabitants. Describe the elements in the universe including stars and galaxies Explain how Earth and the Solar System fit into the greater universe. GRADING Tests and Quizzes 30% Class assignments (Homework/Notebook) 30% Lab Reports/Notebook 25% Projects/Presentations 15% Total 100% EMPLOYABILIT Y This grade will be based on effort, use of class time, attendance and behavior. Any missing assignments or poor attendance (including tardies) will impact this grade. ABSENT WORK Missed tests and quizzes (that arise from excused absences) can only be made up before or af ter school in this room. Talk to me to make other arrangements if your situation requires it! Students must complete any, and all, make -up assignments/quizzes before the end of the current unit or they will receive zeroes. All absent work is due two days later for every day absent, but by the end of the unit. LATE WORK All work is due by the end of the school day of the assigned due date. Must be completed by the next day after the due date for ½ credit. Other wise, it will receive a zero. ACADEMIC INTEGRIT Y Cheating will not be tolerated. This includes copying homework. See syllabus for school guidelines for Academic integrity. Be professional in your work —do your best work at all times. HALL PASSES Four hall passes per quarter Ask permission Sign out in hall pass binder 5 minute limit No visiting vending machines! CLASSROOM EXPECTATIONS What I expect from you The KR way To begin Class Each day: On time In your seat when the bell rings, working on the DMA independently Have necessary supplies and textbook CLASSROOM EXPECTATIONS During Class Don’t talk when I am talking-common courtesy Participate fully in all activities Try your hardest-do your best work Allow others to do their best work-Respect Treat lab and classroom supplies, etc. with respect Absolutely no cell phones or eating! WHAT YOU CAN EXPECT FROM ME. Respect Understanding High Expectations SUPPLIES Composition Notebook These will be used for notes and assignments Paper Calculator Writing utensils: Pen or Pencil Highlighters UNIT 1: ISLAND EARTH Astronomy DMA #1 8/31/12 Grab a DMA sheet and a book and turn to page 1 (the beginning of Chapter 1) Read the 3 paragraphs on page 1 Look at the pictures on pages 2-3. Answer on your DMA sheet: What do you think a Local Group is? COSMIC POSTCARD PROJECT OVERVIEW Goal: apply knowledge of cosmic structures (levels). Role: Vacationer (to favorite spot on Earth) Audience: Friend or family (not on vacation with you.) Strong Verb: Explain or describe Product: Large-scale postcard CH. 1:OUR PLACE IN THE UNIVERSE DETERMINE YOUR COSMIC ADDRESS Read the section titled “1.1A Modern View of the Universe” on pages 4-5 for help & information. Your task: Think about where you went OR the best thing you did this summer Where were you? Make a postcard telling me where you were in the Universe FINISH THIS TODAY! Standards: Graphic: one side Narrative/description of your trip Emphasize the location and activities done on vacation Describe the unique traits of Planet Earth Proper address using cosmic neighborhood concept DMA 9/04/12 • GET OUT YOUR POSTCARD SO WE CAN FINISH THEM. I HAVE A FEW SUGGESTIONS FOR YOU. FINISHING YOUR POSTCARD Narrative Description of Trip: Destination description: Place names, geography are described Activities description: Specific and variety of activities are described with clarity and well-chosen adjectives. Unique Properties of Earth: Unique and varied aspects of Earth are emphasized: Atmosphere: gases, winds, colors Geology: rocky surface Life forms Water CHAPTER 1: OUR PLACE IN THE UNIVERSE Now, time for a pre-test All you need is a pencil (no pens) Clear your desk Reminder-test time is quiet time COSMIC POSTCARD: GALLERY WALK •Purpose: students will carefully examine and evaluate the work of their peers. GALLERY WALK PROCESS •Please visit each student’s postcard You will visit all postcards, however you will give written feedback to only five students. •Using the Post-it™ notes provided to you, write at least one “constructive” suggestion for each student. In addition, please write a specific “praise” for him or her. SUMMARY •In short, you will view all students’ work. •Please choose five students, write two comments per student, for a total of ten comments. •Lastly, select the student whose work is, in your opinion, the best of the class. Write their name on a Post-it™ note and drop it in the Comment Box. WHAT IS THE NAME OF THE GALAXY WE LIVE IN? DMA 9/5/12 WHAT DO WE CALL THE GALAXY CLUSTER WE LIVE IN? COSMIC ADDRESS POST CARD GALLERY WALK Place your post card spread out around the room on the lab counters Walk around and leave comments for 5 postcards. o2 comments for each of the 5 you choose o Helpful advice oPositive comment—a compliment Submit comment post-its with your postcard Submit post-it to vote for Best Card up front. DMA 9/6/12 NAME 3 THINGS WE HAVE ON OUR PLANET THAT WE DON’T FIND ON OTHER PLANETS. CHAPTER 1: OUR PLACE IN THE UNIVERSE Scale in the Universe by Bill Nye Draw a model of the solar system with a scale in inches (i.e. 3 inches = 1 AU) Draw the sun on one edge of your paper Draw orbits (partial circles) the appropriate distances for the planets per the scale. Place a filled circle on the appropriate orbit and label with the name of the planet. Note: you may have to use several sheets and stack them to fold out to show the whole system. Comment upon the size of the Solar System and distances of the planets from the sun. DISTANCES OF PLANETS FROM SUN Planet Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto* Distance (from Sun) 1A.U.=3in. 57,910,000 km 0.387 A.U. 108,200,000 km 0.723 A.U. 149,600,000 km 1.000 A.U. 227,940,000 km 1.524 A.U. 778,330,000 km 5.203 A.U. 1,424,600,000 km 9.523 A.U. 2,873,550,000 km 19.208 A.U. 4,501,000,000 km 30.087 A.U. 5,945,900,000 km 39.746 A.U. THE SOLAR SYSTEM Comment upon the size of the Solar System and distances of the planets from the sun. • What do you notice about the difference between the distances to the first 4 planets and the distances to the last 4 planets? Video: “The Solar System: A First Look” DMA 9/7/12 Get out a blank sheet of paper or your composition notebook and copy down the following assignment: Assignment title: Are we alone? Please respond to the following question: “Are we (on Earth) alone in the universe?” Write your opinion and the reasons you believe this to be true. Include the question and write at least one paragraph (8 sentences). Use as many reasons, details, facts, and opinions as you can find in support of your answer. Cite a minimum 2 websites. We will be going to the library to research the answer! DMA 9/8/12 Is there life on another planet? What was the most convincing argument you read that argued that, yes, there is life out there? ANNOUNCEMENTS Tomorrow: • Guest lecturer • Thursday: • Go to the Museum of Flight to hear about the Mars rover “Curiosity” for extra credit!! Starts at 7p.m. Saturday: • Star party @ Snoqualmie Point park • If you don’t go you will have an alternate assignment • More details on that from our Guest lecturer tomorrow DMA 9/11/12 What is a constellation? (Grab your postcard from the front counter!) DISTANT MIRRORS Objectives: • Describe the suitability of Earth for study of astronomy • Explain how we use technology to determine the existence of life on Earth and elsewhere Distant Mirror • Read the article quietly and individually for 15 minutes • Answer the Discussion Questions as a team of 3 • Submit one team paper with all names DMA 9/12/12 How did scientists prove that they could detect life on other planets? GO TO THE MUSEUM OF FLIGHT TO HEAR ABOUT THE MARS ROVER “CURIOSIT Y” FOR EXTRA CREDIT!! STARTS AT 7P.M. STAR PARTY • Star party @ Snoqualmie Point park • 8-10 p.m. • If you don’t go you will have an alternate assignmentthis will take at least 1-2 hours. DISTANT MIRRORS Objectives: • Describe the suitability of Earth for study of astronomy • Explain how we use technology to determine the existence of life on Earth and elsewhere Distant Mirror • Finish answering the Discussion Questions as a team of 3 • Submit one team paper with all names DMA 9/13/12 What signs of life can be detected from space? STARGAZING Watch the video and take one page of notes At least 20 facts or statements DMA 9/14/12 Get your book and finish your notes on sections 1.1 and 1.2. COSMIC PERSPECTIVE Modern View & Scale of the Universe •Read Section 1.1 and 1.2 • In your notebook: Take 2 pages of notes STAR PARTY • Star party @ Snoqualmie Point park • 8-10 p.m. • Carpooling is strongly recommended. Parking at the Snoqualmie Point Park is very limited. If the loop parking is filled, visitors will need to park outside the Park gate and walk in. TASK Please title today’s assignment on a sheet of notebook paper: o o o o Name Date Period Title: Privileged Planet film Create a T-chart on your paper to form two columns. You can also fold it down the middle. DMA 9/17/12 When looking at the night sky, how can you find the North Star? THE PRIVILEGED PLANET: FILM HYPOTHESES Hypothesis #1 Hypothesis #2 Earth possesses the conditions that, until proven otherwise, allow for intelligent life to exist only on Earth. Earth’s properties also make it strangely wellsuited for viewing and analyzing the universe; in other words the study of astronomy. FILM TASK For each of the two stated hypothesis, please identify, record, and describe the various observations and data that are used to support them. List a minimum of 3 items per hypothesis. Feel free to create a list of these items in each column. These notes will be used as a basis for your post -film reflection and Monday’s class discussion. PRIVILEGED PLANET: REFLECTION Based on your examination of the evidence presented in the film, please determine a conclusion for one hypothesis. In doing so, please include these elements: Rephrase the hypothesis Indicate what the data “say”: Support hypothesis Do not support (can’t tell clearly one way or the other) Contradict (reject) Identify at least two data that your conclusion relies on. NAME 4 THINGS THAT ALLOW EARTH TO SUPPORT LIFE. DMA#1 9/18/12 ASTRONOMY PICTURE OF THE DAY http://apod.nasa.gov/apod/astropix.html SPACESHIP EARTH The Earth travels through space at over 60,000 miles per hour! How long does it take to go around the Sun once? One year, of course!! How long does it take the Earth to rotate on its axis? 24 hours! SPACESHIP EARTH The Earth is tilted on its axis by 23.5 o What causes the seasons? As the Earth goes around the Sun, the Northern and Southern hemispheres take turns being closer to the Sun. SPACESHIP EARTH Fall Equinox Summer Solstice Winter Solstice Spring Equinox SPACESHIP EARTH We are not only traveling around the Sun, our entire solar system is traveling around the center of the Milky Way Galaxy. It takes us 230 million years to make one rotation, which means… Our Solar system moves around the galaxy at about 600,000 miles per hour! SPACESHIP EARTH The Expanding Universe Edwin Hubble discovered 2 surprising facts: 1. Virtually every galaxy outside the Local Group is moving away from us 2. The more distant a galaxy is, the faster it appears to be racing away from us. THE ADVENTURE OF ASTRONOMY As our circumstances and technology have advance, so has our understanding of how the universe works. We’ve gone from thinking the Earth was the center of the Universe, to knowing that we are part of an infinite and expanding universe. FOR THE REMAINDER OF CLASS Finish “Privileged Planet” reflection. Finish your notes on sections 1.1 and 1.2 Read “ The Big Picture” on page 35. We will have a quiz on Friday (we will review important concepts before then) M57 we saw on Saturday! The Ring Nebula WHAT IS THE DIFFERENCE BETWEEN AN EQUINOX AND A SOLSTICE? DMA #2 9/19/12 DMA#3 9/20/12 What element was the first to be created during the Big Bang? 1. THE SUN AND PLANETS FORMED FROM A SOLAR NEBULA. The most successful model of the origin of the solar system is called the Nebular (or Accretion) Hypothesis; some call it a theory. According to this hypothesis, the solar system formed from a cloud of interstellar material called the solar nebula This occurred 4.56 billion years ago (as determined by radioactive agedating). 2. THIS NEBULA FLATTENED INTO A DISK. The solar nebula, by mass, was 98% hydrogen and helium; formed shortly after the Big Bang. The 2% heavier elements were produced much later as heavy stars died. The nebula flattened into a disk in which all the material orbited the center in the same direction, just as do the present-day planets. The heavier elements were in the form of ice and dust particles. The Sun formed by “gravitational contraction” of the center of the nebula. Meaning, the center grew by gobbling up the smaller bits of matter that surrounded it. Af ter 100 million year s , temperatures at the protosun’s center became high enough to ignite nuclear reactions that conver t hydrogen into helium (forming a true star.) 3. THE PLANETS FORMED BY THE ACCRETION (GATHERING) OF “PLANETESIMALS” (LITTLE PLANETS) AND THE ACCUMULATION OF GASES IN THE SOLAR NEBULA . IN CONCLUSION… DMA#4 9/21/12 Describe accretion. ASTRONOMY PICTURE OF THE DAY http://apod.nasa.gov/apod/astropix.html TO DO TODAY Explore Ch. 9 Answer questions in your composition books DMA#5 9/24/12 Why is it so difficult to study geology on other Planets? What types of features are easiest to study? DMA#6 9/25/12 Name 2 differences between Jovian and Terrestrial planets. DMA#7 9/26/12 What creates Jupiter’s magnetic field? The magnetic fields of terrestrial planets are produced by metals such as iron in the liquid state The magnetic fields of the Jovian planets are generated by metallic hydrogen Also hypothesized is water with ionized molecules dissolved in it TO DO TODAY Finish “Extreme Planets” Finish your vocabulary-the words can be found in Chapter 8 on pages 198-211. DMA#8 9/27/12 What is the difference in shape between the Kuiper belt and the Oort cloud? DMA#2 10/3/12 Where is the asteroid belt located in our Solar System? DMA#3 10/5/12 Which planet is the hottest? Why? Reminders: Pay your $5 Turn in permission slip a.s.a.p. DMA#4 10/8/12 How do the interiors of planets get hot? Reminders: Pay your $5 Turn in permission THIS WEEK! PLANETARY ATMOSPHERES Mercury Made of: helium, sodium, oxygen No weather-there’s not enough atmosphere! PLANETARY ATMOSPHERES Venus Made of: mostly Carbon dioxide (96%) and a little Nitrogen (3.5%) Weather-slow winds with no big storms and lots of acid rain from sulfuric acid clouds PLANETARY ATMOSPHERES Earth Made of: mostly Nitrogen (77%) lots of Oxygen (21%), argon, water vapor, and other trace elements Wind over the whole planet-global wind patterns, storms, hurricanes Clouds made of water vapor PLANETARY ATMOSPHERES Mars Made of: mostly Carbon dioxide (95%), Nitrogen (2.7%) and Argon (1.6%) Weather-some wind and dust storms, but there is very little pressure and the atmosphere is very thin WEATHER ON MARS Video from Discovery Streaming PLANETARY ATMOSPHERES What is an atmosphere? the layer of gases that surround a world can be either molecules or atoms which create pressure-we feel the pressure of 1 atm, on Venus we would feel the pressure of 90 atmospheres Where does the atmosphere end? There’s not a specific ending place-it kind of fades away ATMOSPHERIC STRUCTURE 3 things that would determine how sunlight would heat a planet with no atmosphere: 1. Distance from the Sun the closer it is, the more energy from sunlight reaches the surface 2. How much sunlight the planet absorbs vs. reflects 3. How fast the planet rotates if it has a short day, the temperatures will be more even than if there is a really long day ATMOSPHERIC STRUCTURE How does an atmosphere keep a planet warm? Gases can absorb infrared light and heat up Greenhouse gases trap infrared radiation and this helps heat the lower atmosphere (where we live!) The greenhouse gases are gases that are good at absorbing infrared light: Water vapor Carbon dioxide Methane DMA#5 10/9/12 Is the greenhouse effect a good thing or a bad thing?Explain. Reminders: Pay your $5 Turn in permission THIS WEEK! ATMOSPHERIC STRUCTURE Layers of the atmosphere ATMOSPHERIC STRUCTURE 7. How does the fact that our atmosphere scatters light benefit us? What would it be like if our atmosphere didn’t scatter light? Without scattering we would be able to see the stars during the daytime! Also, shadows would be pitch black, so walking down the alley in a big city would be like night! ATMOSPHERIC STRUCTURE Why is the sky blue? Light scattering makes the sky appear blue Blue light is scattered while the red light goes straight through the atmosphere ATMOSPHERIC STRUCTURE Why do sunsets appear red? Sunlight passes through more atmosphere to reach you-most of the blue light is “scattered away” leaving the red behind. ATMOSPHERIC STRUCTURE Describe how the greenhouse ef fect works and why it is important to life on Earth. Light from the sun warms the atmosphere and ground The “greenhouse” gases absorb heat, then re-emit it in all directions This helps heat the surface and keeps the troposphere warm Importance? Because it keeps us warm and regulates our temperatures so we don’t have very extreme temperature shifts ATMOSPHERIC STRUCTURE Why is the stratosphere called the stratosphere? There isn’t any convection, so the air isn’t moving much and becomes layered-AKA stratified Airplanes glide smoothly here because of the lack of air movement. How does the ozone in the stratosphere benefit us? It absorbs most of the Sun’s UV radiation, which is very damaging to us ATMOSPHERIC STRUCTURE Figure 10.9 a. Which one of the three planets shows the biggest temperature increase due to the greenhouse effect? b. Which planet has the most uniform temperature from high to low altitude? c. Is the Earth’s temperature higher at and altitude of 25km or 50km? 10.3 MAGNETOSPHERES AND THE SOLAR WIND Why is the magnetosphere so important to us? Solar wind = charged particles from the Sun The magnetosphere will either divert those particles or trap them in the Van Allen Belts They can produce beautiful auroras in the North and South poles-where the North and South poles of the magnetosphere come close to the Earth’s surface WHY IS THE SKY BLUE? DMA 10/10/12 10.4 WEATHER AND CLIMATE 14. What is the difference between weather and climate? Weather is the varying conditions and combinations of wind, clouds, temperature, and pressure Can change with the seasons and atmospheric conditions, can vary dramatically by the month, day or even hour Climate is the long term average of all the weather in an area and generally stays the same over long periods of time 10.4 WEATHER AND CLIMATE 15. Why doesn’t Venus experience seasons? Because it isn’t tilted! Both hemispheres stay in the same location relative to the Sun. 10.4 WEATHER AND CLIMATE What are the 2 major factors affecting global wind patterns? 1. Atmospheric heating: the air at the equator heats and expands, then flows towards the poles and sinks, creating convection cells Let’s compare Earth and Venus… The circulation of the Venusian atmosphere is dominated by two huge convection currents in the cloud layers, one in the northern hemisphere and one in the southern hemisphere 10.4 WEATHER AND CLIMATE What are the 2 major factors affecting global wind patterns? 2. Planetary rotation: basically the rotation of the planet pushes the air sideways -called the Coriolis effect 10.4 WEATHER AND CLIMATE How does the Coriolis effect change the shape and movement of the circulation pattern of winds on Earth? Breaks up the convection cells so there are 6 instead of 2 (3 per hemisphere) Causes air to circulate counter clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere 10.4 WEATHER AND CLIMATE EARTH VS. VENUS: CLOUDS AND PRECIPITATION Similarities: Sun warms the atmosphere at the equator and creates convection cells Clouds are always present Clouds contain water Rain forms and falls Differences: On VenusClouds contain Sulfuric acid mixed with the water(both of these are replenished by volcanic eruptions) Rain that falls evaporates long before it hits the ground 10.4 WEATHER AND CLIMATE Mars Clouds can formespecially over its big volcano-Olympus Mons Barely any water in the atmosphere, but there is some hidden under the polar CO2 ice caps There may be more water under the surface that helps form the geologic features of Mars 10.5 ATMOSPHERIC ORIGINS AND EVOLUTION How are atmospheres created? From 3 different processes Outgassing- the outpouring of gases from the earth's interior Evaporation/sublimationsurface liquids evaporate into the atmosphere Bombardment-micrometeorites can create only a very thin atmosphere, this is the main source of atmosphere for the Moon and Mercury 10.5 ATMOSPHERIC ORIGINS AND EVOLUTION 20. What is outgassing? Why is it important? It’s important because it helps create and replenish atmospheres 21. What are some ways an atmosphere can lose gas? Thermal escape-a molecule moves fast enough to escape gravity Bombardment Atmospheric cratering Condensation Chemical reactions 10.5 ATMOSPHERIC ORIGINS AND EVOLUTION What are the 3 things that determine if a gas can be lost by thermal escape? 1. The planet’s escape velocitythe larger the planet the stronger the gravity 2. Temperature-higher temperature means faster movement 3. Mass-it’s easier for lighter particles to move fast enough to escape 10.6 HISTORY OF THE TERRESTRIAL ATMOSPHERES 23. The Moon and Mercury: what is their only source of new gas? Bombardment from micrometeorites How do they lose gas particles? Both are small so they have low gravitational pull and the particles can move fast enough to escape Other times they are stripped away by solar wind 10.6 HISTORY OF THE TERRESTRIAL ATMOSPHERES 24. Mars: what stripped away the majority of its atmosphere? it’s possible that Mars used to have a thick atmosphere from volcanic outgassing As the planet cooled it lost its magnetosphere the atmosphere was then stripped away by the solar wind 10.6 HISTORY OF THE TERRESTRIAL ATMOSPHERES 25. Venus: Why is it hotter than Mercury even though it is further from the Sun? What is one piece of evidence that Venus may have once had a lot of water vapor in its atmosphere? An unusually high amount of deuterium-an isotope of hydrogen that can be left behind when water molecules are broken apart by UV radiation. WHAT IS THE CORIOLIS EFFECT? DMA 10/11/12 THE CORIOLIS EFFECT The rotation of the planet pushes the air sideways (ocean currents, too) DMA 10/15/12 WHAT MYSTERY DID ASTRONAUTS SOLVE USING A BAGGIE OF SUGAR? TERRESTRIAL ATMOSPHERES Reflection-Answer in your notebooks What makes our atmosphere so unique and suitable for life? Give at least 4 pieces of evidence to support your claim. Include information on the atmospheres of at least 2 other terrestrial planets in comparison with Earth. DMA 10/17/12 OF THE 4 TERRESTRIAL PLANETS, WHAT IS THE RELATIONSHIP BETWEEN SIZE AND THICKNESS OF ATMOSPHERE? DMA 10/18/12 HOW LONG AGO DID THE BIG BANG OCCUR? DMA 10/19/12 WHY DID MATTER WIN THE BATTLE WITH ANTIMATTER? DMA 10/23/12 HOW CAN AN ATMOSPHERE LOSE GAS? HOW CAN AN ATMOSPHERE LOSE GAS? Thermal escape-a molecule moves fast enough to escape gravity Bombardment Atmospheric cratering Condensation Chemical reactions TO DO TODAY You should have turned in: Big Bang review Cosmic Neighborhood review You need to finish: Unit 1 Review Questions: p. 222:1-4, 6,7,10, 11, 12 P. 284-5: #1,3,4,6,7,10,11,13,14,15 New Unit 1 Test Review REMINDERS Lunch-bring one or money to buy Dress for the weather-cold and rainy THINK, PAIR, SHARE When we researched “Are We Alone” many of you decided that there is life elsewhere in the Universe, then we watched “Privileged Planet” and many of you said there is no life out there. Think about the evidence you learned in both activities and now tell me what you think. COMPARATIVE PLANETOLOGY: OUR SOLAR SYSTEM THERE ARE T WO BROAD CATEGORIES OF PLANETS: EARTHLIKE (TERRESTRIAL) AND JUPITERLIKE (JOVIAN) All of the planets orbit the Sun in the same direction and in almost the same plane Most of the planets have nearly circular orbits m D V DENSITY The average density of any substance depends in part on its composition The terrestrial (Earth-like) planets are made of rocky materials and have dense iron cores, which gives these planets high average densities The Jovian (Jupiter-like) planets are composed primarily of light elements such as hydrogen and helium, which gives these planets low average densities THE TERRESTRIAL PLANETS The four innermost planets are called terrestrial planets Relatively small (with diameters of 5000 to 13,000 km) High average densities (4000 to 5500 kg/m 3 ) Composed primarily of rocky materials JOVIAN PLANETS ARE THE OUTER PLANETS Jupiter, Saturn, Uranus and Neptune are Jovian planets Large diameters (50,000 to 143,000 km) Low average densities (700 to 1700 kg/m 3 ) Composed primarily of hydrogen and helium. S E V E N L A R G E S T S AT E L L I T E S A R E A L M O S T A S B I G A S T H E T E R R E S T R I A L P L A N E T S Comparable in size to the planet Mercury The remaining satellites of the solar system are much smaller SPECTROSCOPY REVEALS THE CHEMICAL COMPOSITION OF THE PLANETS The spectrum of a planet or satellite with an atmosphere reveals the atmosphere’s composition If there is no atmosphere, the spectrum indicates the composition of the surface. The substances that make up the planets can be classified as gases, ices, or rock, depending on the temperatures and pressures at which they solidify The terrestrial planets are composed primarily of rocky materials, whereas the Jovian planets are composed largely of gas PHASES AND PHASE DIAGRAM TERRESTRIALS JOVIANS PLANET COMPOSITION Hydrogen and helium are abundant on the Jovian planets, whereas the terrestrial planets are composed mostly of heavier elements Mars Jupiter ASTEROIDS (ROCKY) AND COMETS (ICY) ALSO ORBIT THE SUN Asteroids are small, rocky objects Comets and Kuiper Belt Objects are made of “dirty ice” All are remnants left over from the formation of the planets The Kuiper belt extends far beyond the orbit of Pluto Pluto can be thought of as the largest member of the Kuiper belt But it’s still considered a planet by IAU agreement CRATERING ON PLANETS AND SATELLITES Result of impacts from interplanetary debris when an asteroid, comet, or meteoroid collides with the surface of a terrestrial planet or satellite, the result is an impact crater Geologic activity renews the surface and erases craters extensive cratering means an old surface and little or no geologic activity geologic activity is powered by internal heat, and smaller worlds lose heat more rapidly, thus, as a general rule, smaller terrestrial worlds are more extensively cratered Largest Volcano in Solar System (Olumpus Mons) Craters on the Moon A PLANET WITH A MAGNETIC FIELD INDICATES AN INTERIOR IN MOTION Planetary magnetic fields are produced by the motion of electrically conducting substances inside the planet This mechanism is called a dynamo If a planet has no magnetic field this would be evidence that there is little such material in the planet’s interior or that the substance is not in a state of motion THE DIVERSIT Y OF THE SOLAR SYSTEM IS A RESULT OF ITS ORIGIN AND EVOLUTION The planets, satellites, comets, asteroids, and the Sun itself formed from the same cloud of interstellar gas and dust The composition of this cloud was shaped by cosmic processes, including nuclear reactions that took place within stars that died long before our solar system was formed Different planets formed in different environments depending on their distance from the Sun and these environmental variations gave rise to the planets and satellites of our present-day solar system Amid this vast and overwhelming space and in these boundless solar archipelagoes, how small is our own sphere, and the earth, what a grain of sand! — Hippolyte Taine, The Ancient Regime, 1881. When you're finally up at the moon looking back on earth, all those dif ferences and nationalistic traits are pretty well going to blend, and you're going to get a concept that maybe this really is one world and why the hell can't we learn to live together like decent people. — Frank Borman, Apollo 8, Newsweek, 23 December 1968. To see the earth as it truly is, small and blue and beautiful in that eternal silence where it floats, is to see ourselves a riders on the earth together, brothers on that bright loveliness in the eternal cold—brothers who know now they are truly brothers. — Archibald MacLeish, American poet, 'Riders on ear th together, Brothers in eternal cold,' front page of the New York Times, Christmas Day, 25 December 1968 I think the one overwhelming emotion that we had was when we saw the earth rising in the distance over the lunar landscape . . . . It makes us realize that we all do exist on one small globe. For from 230,000 miles away it really is a small planet. — Frank Borman, Apollo 8, press repor ts, 10 Januar y 1969. The view of the Earth from the Moon fascinated me —a small disk, 240,000 miles away. It was hard to think that that little thing held so many problems, so many frustrations. Raging nationalistic interests, famines, wars, pestilence don't show from that distance. — Frank Borman, Apollo 8, 'A Science Fiction World —Awesome Forlorn Beauty,' Life magazine, 17 Januar y 1969. [The Moon] was a sobering sight, but it didn't have the impact on me, at least, as the view of the Earth did. — Frank Borman, Apollo 8, Interview for the PBS T V show Nova, 1999. We learned a lot about the Moon, but what we really learned was about the Earth. The fact that just from the distance of the Moon you can put your thumb up and you can hide the Earth behind your thumb. Everything that you've ever known, your loved ones, your business, the problems of the Earth itself—all behind your thumb. And how insignificant we really all are, but then how fortunate we are to have this body and to be able to enjoy loving here amongst the beauty of the Earth itself. — Jim Lovell, Apollo 8 & 13 astronaut, inter view for the 2007 movie In the Shadow of the Moon It suddenly struck me that that tiny pea, pretty and blue, was the Earth. I put up my thumb and shut one eye, and my thumb blotted out the planet Earth. I didn't feel like a giant. I felt very, very small. — Neil Armstrong If somebody'd said before the flight, "Are you going to get carried away looking at the earth from the moon?" I would have say, "No, no way." But yet when I first looked back at the earth, standing on the moon, I cried. — Alan Shepard A Chinese tale tells of some men sent to harm a young girl who, upon seeing her beauty, become her protectors rather than her violators. That's how I felt seeing the Earth for the first time. I could not help but love and cherish her. — Taylor Wang What was most significant about the lunar voyage was not that man set foot on the Moon but that they set eye on the earth. — Norman Cousins, Cosmic Search magazine, volume 1, number 1, Januar y 1979. As we got further and further away, it [the Earth] diminished in size. Finally it shrank to the size of a marble, the most beautiful you can imagine. That beautiful, warm, living object looked so fragile, so delicate, that if you touched it with a finger it would crumble and fall apart. Seeing this has to change a man. — James B. Irwin No one, it has been said, will ever look at the Moon in the same way again. More significantly can one say that no one will ever look at the earth in the same way. Man had to free himself from earth to perceive both its diminutive place in a solar system and its inestimable value as a life -fostering planet. As earthmen, we may have taken another step into adulthood. We can see our planet earth with detachment, with tenderness, with some shame and pity, but at last also with love. — Anne Morrow Lindbergh, Earth Shine, 1969. We were flying over America and suddenly I saw snow, the first snow we ever saw from orbit. I have never visited America, but I imagined that the arrival of autumn and winter is the same there as in other places, and the process of getting ready for them is the same. And then it struck me that we are all children of our Earth. — Aleksandr Aleksandrov As I looked down, I saw a large river meandering slowly along for miles, passing from one country to another without stopping. I also saw huge forests, extending along several borders. And I watched the extent of one ocean touch the shores of separate continents. Two words leaped to mind as I looked down on all this: commonality and interdependence. We are one world. — John-David Bar toe Viewed from the distance of the moon, the astonishing thing about the earth, catching the breath, is that it is alive. The photographs show the dry, pounded surface of the moon in the foreground, dry as an old bone. Aloft, floating free beneath the moist, gleaming, membrane of bright blue sky, is the rising earth, the only exuberant thing in this part of the cosmos. — Lewis Thomas, The Lives of a Cell: Notes of a Biology Watcher , 1974. For those who have seen the Earth from space, and for the hundreds and perhaps thousands more who will, the experience most certainly changes your perspective. The things that we share in our world are far more valuable than those which divide us. — Donald Williams http://www.spacequotations.com/earth.html