MHE_Rdg_Wonders_LvRdr_G6_Beyond_U5W4_24.pdf

by Bill NagelkerkeLookingLookingFurtherFurther The Hubble TelescopePAIREDREADThe WatchersExpository TextProgram:CR 14Component:LRG6 U5 W4 BPDFVendor:Learning MediaLevel:80CV_CR14_LR_G6_U5W4L80_B_118584.indd 2CV_CR14_LR_G6_U5W4L80_B_118584.indd 224/02/12 2:53 PM24/02/12 2:53 PMSTRATEGIES&SKILLSAPhotography Credit:NASA,ESA,and G.Bacon(STScI)*The total word count is based on words in the running text and headings only.Numerals and words in captions,labels,diagrams,charts,and sidebars are not included.ComprehensionStrategy:RereadSkill:SequenceVocabulary StrategyContext CluesVocabularycolleagues,conservatively,deduction,droned,galaxies,sustain,ultimately,verifyContent StandardsScienceEarth and Space ScienceWord Count:2,971*Program:CR 14Component:LRG6 U5 W4 BPDFVendor:Learning MediaLevel:80Copyright The McGraw-Hill Companies,Inc.All rights reserved.No part of this publication may be reproduced or distributed in any form or by any means,or stored in a database or retrieval system,without the prior written consent of The McGraw-Hill Companies,Inc.,including,but not limited to,network storage or transmission,or broadcast for distance learning.Send all inquiries to:McGraw-Hill EducationTwo Penn PlazaNew York,New York 10121ISBN:978-0-02-118584-9MHID:0-02-118584-0Printed in the United States.1 2 3 4 5 6 7 8 9 DOC 15 14 13 12 11 10IFCIBC_CR14_LR_G6_U5W4L80_B_118584.indd 2IFCIBC_CR14_LR_G6_U5W4L80_B_118584.indd 224/02/12 2:58 PM24/02/12 2:58 PMLookingLookingFurtherFurther The Hubble Telescopeby Bill NagelkerkeEssential QuestionHow does technology lead to discoveries?PAIREDREADIntroduction .2Chapter 1Land or Sky?.4Chapter 2The Amazing Hubble.8Chapter 3Hubbles Last Days.12Conclusion.17Respond to Reading.18The Watchers .19Glossary.22Index.23Focus on Science .24Program:CR 14Component:LRG6 U5 W4 BPDFVendor:Learning MediaLevel:80NASA,ESA,S.Beckwith(STScI)and the HUDF Team 001_009_CR14_LR_G6_U5W4L80_B_118584.indd 1001_009_CR14_LR_G6_U5W4L80_B_118584.indd 124/02/12 2:57 PM24/02/12 2:57 PMIntroductionIntroductionThe two parts of the word telescope come from the Greek language,and they tell a lot about what this tool does.Tele means“far”or“a long way,”and scope means“to see.”So telescope means“far-seeing.”It is a tool that helps you see things that are far away.Before telescopes were invented,people had to explore the night sky with the naked eye.An ancient Greek named Aristarchus,who lived from about 310 to 230 B.C.E.,seems to have been the first person to suggest that Earth orbited the sun.Nobody knows how he justified this claim.Was it just a clever guess?Maybe he watched the night sky so closely that he was certain of his deduction,even without the technology to verify it.By 1609,the Italian scientist Galileo had this technology.He had made a refracting telescope that was specially designed to study the sky.Refracting telescopes bend,or refract,light through a glass lens.This magnifies distant objects.One of Galileos telescopes could make objects appear up to 20 times larger.Through his telescope,Galileo discovered sunspots and Jupiters moons.2Program:CR 14Component:LRG6 U5 W4 BPDFVendor:Learning MediaLevel:80(t)NASA,ESA,S.Beckwith(STScI)and the HUDF Team,(b)National Geographic Society/Corbis001_009_CR14_LR_G6_U5W4L80_B_118584.indd 2001_009_CR14_LR_G6_U5W4L80_B_118584.indd 224/02/12 2:57 PM24/02/12 2:57 PMHubble is a joint project between the space agencies of the United States and Europe.In 1668,the English astronomer Isaac Newton made a reflecting telescope.A reflecting telescope uses mirrors instead of lenses to capture light rays.The magnified image is sharper than in a refracting telescope because the light does not have to travel through thick glass lenses.Other people improved on these two types of telescopes.In 1672,a French inventor named Laurent Cassegrain made a reflecting telescope using two curved mirrors instead of one.The Hubble Space Telescope is a form of reflecting telescope with a light-gathering mirror 94 inches in diameter.Hubble has enabled astronomers to see deeper into space and discover galaxies never seen before.It has helped scientists solve some of the puzzles of the universewhile also posing new ones.Unlike Galileo,todays astronomers do not need to look through telescopes to make observations.Instead,they look at images recorded by cameras and other electronic devices within the telescopes.This is the way the Hubble telescope works.Program:CR 14Component:LRG6 U5 W4 BPDFVendor:Learning MediaLevel:803NASA-STScI 001_009_CR14_LR_G6_U5W4L80_B_118584.indd 3001_009_CR14_LR_G6_U5W4L80_B_118584.indd 324/02/12 2:57 PM24/02/12 2:57 PMWhen Galileo observed the moon through his telescopes,he found that it was covered in craters.It was not smooth as people had thought.He also discovered four of Jupiters moons,the rings around Saturn,and many more stars than could be seen by the naked eye.It was becoming clear that exploring the universe with telescopes would uncover a lot of new knowledge.Astronomers were discovering that the universe was much larger and more complex than anyone had realized.Land-based telescopes became bigger and better.In 1873,the Alvan Clark company completed a refracting telescope that was,at the time,the largest in the world.It helped astronomers make many important discoveries.For example,in 1877,the telescope enabled astronomer Asaph Hall to discover the two moons that orbit Mars.The first permanent mountaintop observatory was the Lick Observatory in California,built in 1887.Its refracting telescope was the worlds largest until 1897 when the Yerkes Observatory in Wisconsin opened.More than 100 years later,Yerkes still boasts the worlds largest refracting lens,at 40 inches.Chapter 1Land or Sky?Land or Sky?Through his telescope,Galileo was able to see the craters on the moon.Program:CR 14Component:LRG6 U5 W4 BPDFVendor:Learning MediaLevel:804(t)NASA,ESA,S.Beckwith(STScI)and the HUDF Team,(b)StockTrek/Getty Images001_009_CR14_LR_G6_U5W4L80_B_118584.indd 4001_009_CR14_LR_G6_U5W4L80_B_118584.indd 424/02/12 2:57 PM24/02/12 2:57 PMCopernicus was named for the Polish astronomer Nicolaus Copernicus,who,like Aristarchus,argued that the planets revolved around the sun.The problem with land-based optical telescopes is that they are limited in what they can see in space.A German rocket scientist named Hermann Oberth had an idea.He thought that launching a telescope into space by rocket could help scientists see farther into the universe.This idea became a reality in 1966.Between 1966 and 1972,four satellites carrying telescopes were sent into space.They were called Orbiting Astronomical Observatories(OAOs).The most successful was called Copernicus.Its reflecting telescope was the largest that had ever been put into orbit.Optical and Radio TelescopesOptical and radio telescopes are two kinds of telescopes.Optical telescopes capture visible light.This is the light we can see with our eyes,such as the light from stars.The Hubble telescope is one of the biggest and best-known examples of an optical telescope.Radio telescopes use radio waves to create images.Radio waves,which are invisible,can come from objects such as stars and galaxies.Program:CR 14Component:LRG6 U5 W4 BPDFVendor:Learning MediaLevel:805NASA001_009_CR14_LR_G6_U5W4L80_B_118584.indd 5001_009_CR14_LR_G6_U5W4L80_B_118584.indd 524/02/12 2:57 PM24/02/12 2:57 PM The Hubble telescope is about the size of a large school bus or truck.solar panels pbtgtbble telescope t the size ge school truck.solar The OAOs ultimately paved the way for other orbiting telescopes.In 1977,the U.S.government agreed to the building of the Hubble Space Telescope.Thirteen years later,in 1990,the space shuttle Discovery carried this telescope into space.The Hubble Space Telescope(also known as HST,or simply Hubble)was named after the famous American astronomer,Edwin Hubble.Hubble now orbits 353 miles(568 kilometers)above Earth.The pictures it takes are some of the clearest images ever seen of celestial objects.Hubble has a pair of solar wings that make it resemble a giant silver insect.The wings are the solar panels that harvest sunlight to power Hubbles instruments,such as its computers and radio transmitters.Some of the energy generated from the sunlight is stored in onboard batteries.This allows Hubble to operate when it is in Earths shadow.The Hubble Space TelescopeThe space shuttle Discovery blasts off,taking Hubble into orbit.Program:CR 14Component:LRG6 U5 W4 BPDFVendor:Learning MediaLevel:806NASA,Illustration:Carlos Aon001_009_CR14_LR_G6_U5W4L80_B_118584.indd 6001_009_CR14_LR_G6_U5W4L80_B_118584.indd 624/02/12 2:57 PM24/02/12 2:57 PM At first things did not go according to plan with the Hubble telescope.After its launch,scientists discovered minor problems with the telescopes main mirror and solar panels.The first images captured by Hubble were less clear than had been expected.These problems were not fixed until 1993 when NASA sent the space shuttle Endeavour on a repair mission.Endeavours astronauts installed additional lenses to fix the problem with the mirror and replaced the solar panels.The space shuttle mission was a great success.It showed that,with regular servicing from Earth,Hubble could have a long life.High above Earths atmosphere,Hubble was able to see what other telescopes had never seen before.It sent massive amounts of information back to scientists on Earth.Hubble really was an eye in the sky.Edwin HubbleDuring the 1920s,Edwin Hubble worked at the Mount Wilson Observatory in California.Here he studied spiral nebulae,which are clouds of dust and gas in space.His observations showed scientists that there were other galaxies beyond our own.He went on to prove that the universe is expanding.On the 1993 mission,astronauts used the space shuttles robotic arm to repair Hubble.7Program:CR 14Component:LRG6 U5 W4 BPDFVendor:Learning MediaLevel:80NASA-STScI 001_009_CR14_LR_G6_U5W4L80_B_118584.indd 7001_009_CR14_LR_G6_U5W4L80_B_118584.indd 724/02/12 2:57 PM24/02/12 2:57 PMChapter 2The Amazing HubbleThe Amazing HubbleAs well as being an amazing telescope,Hubble can be thought of as a kind of time machine.Some galaxies are so distant that their light can take billions of years to reach our solar system.At one point,Hubble looked deep into an area of space that appeared to be“empty space.”The NASA scientists who control Hubble from Earth pointed the telescope in this position for ten days.This allowed Hubble to absorb as much light as possible.To the scientists amazement,Hubble sent back pictures that showed thousands of new galaxies of all sizes.The area is now known as the Hubble Deep Field.Hubble has photographed many other amazing phenomena.It has recorded galaxies colliding with one another,the birth of some stars,and the death of others.Scientists also have used Hubble data to better pinpoint the age of the universe.They believe the evidence shows that the universe is around 14 billion years old.They also now believe the universe is expanding at a faster pace.Some scientists had thought it was slowing down.Hubbles fascinating images have captured the beauty of space.8Program:CR 14Component:LRG6 U5 W4 BPDFVendor:Learning MediaLevel:80(t)NASA,ESA,S.Beckwith(STScI)and the HUDF Team,(b)NASA,ESA,and M.Livio and the Hubble 20th Anniversary Team(STScI)001_009_CR14_LR_G6_U5W4L80_B_118584.indd 8001_009_CR14_LR_G6_U5W4L80_B_118584.indd 824/02/12 2:57 PM24/02/12 2:57 PM123456123456Illustration:Carlos AonScientists at NASAs Goddard Space Flight Center in Greenbelt,Maryland,control Hubble.They send radio messages via satellites to Hubble,telling the telescope where to look and what to look for.The radio signals are picked up by antennae on the telescope.Onboard computers record everything Hubble sees.Hubble then sends that information back to Earth the same way it receives its instructionsby radio via satellite.A ground station in White Sands,New Mexico,receives Hubbles messages and relays them to Goddard.Goddards scientists send the data to the Space Telescope Science Institute(STScI)in Baltimore,Maryland to be interpreted.Their astronomer colleagues from around the world can then download the data over the Internet for use in their own research.Capturing Data from the StarsDataStarlightHubble Space TelescopeTracking and Data Relay SatelliteGround Station,White Sands,NMGoddard Space Flight Center,Greenbelt,MDSpace Telescope Science Institute,Baltimore,MDProgram:CR 14Component:LRG6 U5 W4 BPDFVendor:Learning MediaLevel:809001_009_CR14_LR_G6_U5W4L80_B_118584.indd 9001_009_CR14_LR_G6_U5W4L80_B_118584.indd 924/02/12 2:57 PM24/02/12 2:57 PMLO RESHubbles discoveries help not only working scientists but also amateur astronomers and young scientists.One of the ways this happens is through the STScI astronomy program.This program for college students runs for ten weeks each summer.Students work with institute staff and other researchers to interpret Hubble data and prepare it for release to the public.They also have the opportunity to hear speakers talk about the Hubble telescope and other space and astronomy topics.The STScI also has set up the Hubble Deep Field Academy Web site for younger students.The site gives students a taste of what it is like to receive and interpret the Hubble data.It takes them through the process that astronomers use to interpret Hubbles Deep Field images.By using the Hubble Deep Field Academy Web site,students have the opportunity to study Hubble data.to study Hubble data.10Program:CR 14Component:LRG6 U5 W4 BPDFVendor:Learning MediaLevel:80Ariel Skelley/Blend Images/Getty Images 010_018_CR14_LR_G6_U5W4L80_B_118584.indd 10010_018_CR14_LR_G6_U5W4L80_B_118584.indd 1024/02/12 3:02 PM24/02/12 3:02 PMThis is the deepest Deep Field snapshot yet.Scientists have counted nearly 10,000 galaxies just in this one image.One of the real-world challenges that academy students tackle has to do with distance.It is difficult for astronomers to determine distances between Earth and objects in the Deep Field.The size of an object does not always relate to its distance.Something small may be closer than something large.Astronomers have to try to measure light to determine distance.A light-year is the distance that light can travel in a year.Light travels very fast,and a light-year is approximately 6 trillion miles.That is a 6 with 12 zeroes after it:6,000,000,000,000!A jet moving at a speed of 500 miles per hour would need to fly for 1.34 million years to travel one light-year.One celestial object in the Deep Field is nearly 12 billion light-years away.That means it would take 12 billion years for the light from this object to travel to Earth.11Program:CR 14Component:LRG6 U5 W4 BPDFVendor:Learning MediaLevel:80NASA,ESA,S.Beckwith(STScI)and the HUDF Team 010_018_CR14_LR_G6_U5W4L80_B_118584.indd 11010_018_CR14_LR_G6_U5W4L80_B_118584.indd 1124/02/12 3:02 PM24/02/12 3:02 PMChapter 3Hubbles Last DaysHubbles Last DaysDuring a maintenance mission,Hubble is taken out of service and a