Sample Lesson for Grades 8-9 fromProject Haystack: The Search for Life in the Galaxy The Life in the Universe Series was created by children, teachers, and scientists at the SETI Institute for grades 3-9, with funding from the National Science Foundation (NSF)and the National Aeronautics and Space Administration (NASA).Edna DeVore Pamela HarmanDirector ManagerEducation and Public Outreach Education and OutreachSETI Institute515 North Whisman RoadMountain View, CA 94043650-961-6633 phone650-961-7099 [email protected]://www.seti.org

Life in the Universe Series — Book 6 2Activity 4Calculating Stellar Travel Times.How Long Would It Take to Travel to the Stars?_____________________________________________________________OverviewIn the previous Activity, students learned how to measure the distance to a star, and gained a feeling forhow far away even the closest stars are. But in science fiction, starships cross the galaxy in minutes, andspace travel to distant stars seems like a reasonable option to students.In this Activity, students will consider the enormous amount of time that it would take to get to Sirius, a starthat of one of the Voyager spacecraft is heading towards, using various modes of transportation- somepractical, and some whimsical! This knowledge should lead students to question the practicality ofphysically going to another star system or attempting interstellar communication with an extraterrestrialintelligence by sending a spaceship there.What You NeedFor Each Team of 2-3 Students:› Scissors› Tape or glue› Student Worksheet: \"Bike Years!\"For Each Student:› Student Worksheet: \"Bike Years! Questions\"› Optional Student Worksheet: \"Bike Years vs. Light Years\"Getting Ready1. Copy the Student Worksheets: \"Bike Years!\", \"Bike Years! Questions\", & \"Bike Years vs. Light Years\"if used.2. Divide the class into teams of 2 - 3 students.Classroom Action1. Discussion. Tell your students that they will be figuring out how long it would take to get to Sirius, astar in the constellation Canis Major, using six different modes of transportation, including walking orriding a bicycle (if that were possible, which of course it isn't!).Sirius is the brightest star in the Northern Hemisphere, except for our Sun. Sirius is a relatively \"close\" star,but its distance from Earth is still 8.6 light years. But what is a \"light year\"? Visible light, as well as all ofthe other types of radiation in the electromagnetic spectrum, travels at the speed of light. The distance that Adapted from Project Haystack: The Search for Life in the GalaxySETI Institute, Teacher Ideas Press, Englewood, CO, 1(800) 237-6124

Life in the Universe Series — Book 6 3light travels in one year is called a light-year, about 6 trillion miles or 9.5 trillion kilometers! So how longwould it take to travel to Sirius? It depends upon the speed of our vehicle.OBVIOUSLY THIS IS IMPOSSIBLE but if we were traveling on a bicycle, how long would it take to getto Sirius then? We could figure that out by considering \"Bike Years\". So what is a Bike Year? Followingthe same type of logic as is used to define a \"Light Year\", it would be the distance that a bicycle rider couldride his/her bike in one year, without ever stopping to eat, sleep, or anything else!Note that \"Light Years\" and \"Bike Years\" are both distance measurements, not time measurements.However if we know the distance to our destination, we can calculate how long it would take to travelthere, if we also know the speed of our vehicle.It might take a long time to get to Sirius on a bike, but how about on a spacecraft? As you know, theVoyager spacecraft were equipped with phonograph records that contain pictures and sounds depicting ourworld. One of the Voyager spacecraft is actually headed towards Sirius. If there is an intelligentcivilization living on a planet near that star, how many years will it be until Voyager reaches it?2. Worksheet. Divide the class into teams of 2 - 3 students. Hand out the Student Worksheets: \"BikeYears!\" to each team. Distribute scissors, and glue or tape.3. Activity. Have the students follow the directions given on their Worksheet. They will cut the\"Scrambled Data\" into blocks which will then be pasted onto their blank data chart. Students willbrainstorm together. The only clue that they have to work with is their ability to rank the modes of travelfrom slowest to fastest! You may be surprised at their choices!Teacher Information: The speed of the Voyager spacecraft is actually variable. It left Earth with avelocity of about 97,000 km/hr, but it has been slowing down since then. We give 56,000 km/hr as anarbitrary number for comparison. As Voyager approaches and then passes planets, and later suns, the\"slingshot effect\" will again increase its actual velocity.Optional: You can have students do all of the calculations on the data chart. If you choose to do thelesson in this way, do not hand out the scrambled data. In addition, you could have the students estimatethe speeds for the six modes of travel before giving them the actual accepted values.4. Discussion. After students have completed the Worksheet, engage them in a discussion making sure tocover the correct answers on their Worksheet, discussing anything that they found unusual or surprising.Some students may believe that a \"supersonic jet\" travels faster than the space shuttle! Ask them toconsider traveling around the Earth in a jet plane. How long would it take? Now ask: how long does theSpace Shuttle take to orbit the Earth once? This may help them see the difference. Also have themconsider that the Space Shuttle is meant for \"local\" travel, while the Voyagers were designed to travel muchfurther; they were designed to travel fast!Ask \"Now that you know the speeds of some very fast objects, how fast do you think that light travels\"?Write down all reasonable responses on the board, then write down the accepted value of approximately300,000 km/sec. So what distance is a light year? About 6 trillion miles or 9.5 trillion kilometers!Challenge the students: can they calculate how far away Sirius is in km? Sirius is 8.6 light years away fromthe Earth. Sirius is a mind-boggling 8.17 x 1013 km from the Earth. (Ask students to write this numberwithout scientific notation. How would they say this number? If your students are unfamiliar withscientific notation, you may review it with them.) Adapted from Project Haystack: The Search for Life in the GalaxySETI Institute, Teacher Ideas Press, Englewood, CO, 1(800) 237-6124

Life in the Universe Series — Book 6 4Considering the time and distance constraints that interstellar travel imposes, what do you think of thepossibilities of the interception of the Voyager probe and the message it carries?5. Homework. Hand out the Student Worksheet: \"Bike Years! Questions\". Have the students finish thisin class or assign it as Homework.Optional: Have students also complete the \"Bike Years vs. Light Years\" in class or as Homework.Going FurtherACTIVITY: A SUNNY DAYHave the students work out how fast light travels to Earth from the sun. It takes sunlight 8.3 minutes toreach Earth. How far away must the sun be? Another way to grasp this is to note that if sunlight couldtravel in a curved path around the Earth, a ray of light could go 7 times around the equator in one second.ACTIVITY: THUNDER AND LIGHTNINGYou could compare the speed of sound and the speed of light by reminding them of thunder and lightning.Students will be able to see the object that makes the sound (lightning) before they can hear it (thunder).This is a handy way to prove that the light that travels to their eyes covers the distance faster than the sounddoes. Students may make calculations about how far away the lightning was by how long it takes them tohear the thunder. Adapted from Project Haystack: The Search for Life in the GalaxySETI Institute, Teacher Ideas Press, Englewood, CO, 1(800) 237-6124

Life in the Universe Series — Book 6 5 Calculating Stellar Travel Times. How Long Would It Take to Travel to the Stars? _____________________________________________________________ BIKE YEARS! PAGE ONEName: _______________________________________ Date: _____________________Table 4.1 Blank Bike Years Chart. NOTE: Distance to Sirius = 8.17 x 1013 kmMode Average Distance Time To Getof Travel, Speed Covered In To SiriusSlowest to One YearFastest1.2.3.4.5.6. Adapted from Project Haystack: The Search for Life in the Galaxy SETI Institute, Teacher Ideas Press, Englewood, CO, 1(800) 237-6124

Life in the Universe Series — Book 6 6 Calculating Stellar Travel Times. How Long Would It Take to Travel to the Stars? _____________________________________________________________ BIKE YEARS! PAGE TWOName: _______________________________________ Date: _____________________SCRAMBLED DATA INSTRUCTIONS:1. Cut out these scrambled pieces of data.2. Put all of the modes of travel in the first column of your Worksheet starting with the slowestmode of travel (#1) moving to the fastest mode of travel (#6).3. Once you are confident that this order is correct, glue, tape or write the data for the next threecolumns; average speed in km/hr, distance covered in one year in km/yr, and finally the time that itwould take to get to Sirius using that particular mode of travel.Table 4.2 Bike Years Scrambled Data7 Million 233,000 years Voyager Space Supersonic Jet km each yr. Craft PlaneSpace Shuttle 490 Million 56,000 km/hr 61,320 km each yr. km each yr.1.33 Billion Bike 350 Million 40,000 km/hr Years km each yr.219,000 km each yr. 25 km/hr 11.7 Million 373 Million Years Years117 Million 7 km/hr 167,000 Years 80 km/hr YearsCar 800 km/hr Walking 700,800 km each yr. Adapted from Project Haystack: The Search for Life in the Galaxy SETI Institute, Teacher Ideas Press, Englewood, CO, 1(800) 237-6124

Life in the Universe Series — Book 6 7 Calculating Stellar Travel Times. How Long Would It Take to Travel to the Stars? _____________________________________________________________ BIKE YEARS! QUESTIONS: PAGE ONEName: _______________________________________ Date: _____________________1. Would it be practical to travel to Sirius by any of the modes of travel listed on the Bike YearsActivity chart? Why or why not?2. Do you think that it is possible that one of the Voyager spacecraft would ever be intercepted bya civilization around another star, even if such a civilization exists?3 What travels at the speed of light that is capable of carrying information?4. What would be the most practical way to get information from Earth to Sirius if we knew that acivilization existed around this star?5. If perhaps the simulated message that had been received by a radio telescope here on Earth inActivity 1 had come from Sirius, how long ago would it have been sent? Why?6. SETI scientists are listening to stars that are within 100 light-years of Earth. Why do you thinkthey have chosen this limited distance?7. Proxima Centauri is the closest star to Earth at a distance of 4.3 light years away. If you standoutside on a clear night and see the light coming from it, how long ago did the light leave that star?Explain your answer.8. \"Star Trek\" is a TV show in which a starship goes to other star systems in our Galaxy. Can youthink of any practical problems with this idea? Adapted from Project Haystack: The Search for Life in the GalaxySETI Institute, Teacher Ideas Press, Englewood, CO, 1(800) 237-6124

Life in the Universe Series — Book 6 8 Calculating Stellar Travel Times. How Long Would It Take to Travel to the Stars? _____________________________________________________________ Table 4.3 TEACHER'S KEY FOR \"BIKE YEARS!\"Mode of Travel Speed Distance Time to Get1. Walking 7 km/hr Covered to Sirius 61,320 km each yr. 1.33 Billion years2. Bike 25 km/hr 219,000 km each yr. 373 Million years3. Car 80 km/hr 700,800 km each yr. 117 Million years4. Supersonic 800 km/hr 7 Million 11.7 Million Jet Plane 40,000 km/hr km each yr. years 350 Million 233,000 years5. Space Shuttle km eachyr.6. Voyager 56,000 km/hr 490 Million 167,000 years km each yr.1. More than likely not, since these modes require enormous amounts of time, certainly longerthan anyone's lifetime or even multiple generations. Also, obviously bikes, planes, etc. can't travelthrough space!!2. STUDENT ANSWERS WILL VARY. Accept all reasonable attempts.3. Radio, TV and microwaves in the electromagnetic spectrum. In fact all of the radiation in theelectromagnetic spectrum can carry information.4. Send it as radio waves or TV waves since it requires no mass and travels at the fastest speedpossible, the speed of light.5. The message would have been sent from Sirius 8.6 years ago, since Sirius is 8.6 light yearsaway, and radio waves travel at the speed of light.6. Radio signals would be stronger from stars that are the closest to us. Also, if we receive amessage from a star system and we want to respond, it would take the same number of years to getthere as it did to come here, so for practical purposes we are listening to star systems that aresomewhat closer to us.7. The light would have left Proxima Centauri 4.3 light years ago since light travels at the speed oflight and the star is 4.3 light years away.8. The crew of the starship Enterprise would be dead long before their starship could get to eventhe nearest stars if they are traveling at speeds we know are attainable with present day or evenforeseeable technology! Adapted from Project Haystack: The Search for Life in the Galaxy SETI Institute, Teacher Ideas Press, Englewood, CO, 1(800) 237-6124

Life in the Universe Series — Book 6 9 Calculating Stellar Travel Times. How Long Would It Take to Travel to the Stars? _____________________________________________________________ BIKE YEARS VS. LIGHT YEARSName: _______________________________________ Date: _____________________PART I.Figure out how far a bicycle can travel in one year, assuming a rate of speed of 25 km per hour,with the rider never stopping to eat, drink or sleep. This computed distance will equal ONE BIKEYEAR, or the distance that a bicycle can travel in one year. Bicycle travels at a rate of speed = 25 km/hrX _____ hours per day = _______________ km per dayX _____ days per year = _______________ km per yearTHIS IS THE DISTANCE A BIKE GOES IN ONE YEAR, OR ONE \"BIKE YEAR\".PART II.Figure out how far a ray of light can travel in one year. This computed distance will be consideredONE LIGHT YEAR, or the distance that light can travel in one year. Light travels at a rate of speed = 300,000 km per secondX ____ seconds per minute = __________________ km per minuteX _____ minutes per hour = __________________ km per hourX _____ hours per day = _____________________ km per dayX _____ days per year = _______________________ km per yearTHIS IS THE DISTANCE LIGHT TRAVELS IN ONE YEAR, OR ONE LIGHT YEAR Adapted from Project Haystack: The Search for Life in the GalaxySETI Institute, Teacher Ideas Press, Englewood, CO, 1(800) 237-6124

Life in the Universe Series — Book 6 10 Calculating Stellar Travel Times. How Long Would It Take to Travel to the Stars?_____________________________________________________________ TEACHER'S KEY FOR \"BIKE YEARS VS LIGHT YEARS\"PART I.Figure out how far a bicycle can travel in one year, assuming a rate of speed of 25 km per hour,with the rider never stopping to eat, drink or sleep. This computed distance will equal ONE BIKEYEAR, or the distance that a bicycle can travel in one year. Bicycle travels at a rate of speed = 25 km/hrX __24___ hours per day = 600 km per dayX __365___ days per year = 2.19 X 105 km per yearTHIS IS THE DISTANCE A BIKE GOES IN ONE YEAR, OR ONE \"BIKE YEAR\".PART II.Figure out how far a ray of light can travel in one year. This computed distance will be consideredONE LIGHT YEAR, or the distance that light can travel in one year. Light travels at a rate of speed = 300,000 km per secondX __60__ seconds per minute = 1.80 X 107 km per minuteX __60__ minutes per hour = 1.08 X 109 km per hourX __24___ hours per day = 2.59 X 1010 km per dayX __365___ days per year = 9.46 X 1012 km per yearTHIS IS THE DISTANCE LIGHT TRAVELS IN ONE YEAR, OR ONE LIGHT YEAR Adapted from Project Haystack: The Search for Life in the GalaxySETI Institute, Teacher Ideas Press, Englewood, CO, 1(800) 237-6124

# Project Haystack: The Search for Life in the Galaxy

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**Description: ** Sample Lesson for Grades 8-9 from Project Haystack: The Search for Life in the Galaxy The Life in the Universe Series was created by children, teachers, and ...

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