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Dean R Berry Is There Life on Other Planets?

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Dean R Berry Is There Life on Other Planets?

  1. 1. Is There Life on Other Planets? A Teachers’ Choice Library Unit By Dean Berry, Ed. D.
  2. 2. Does life exist beyond earth? Read, Discuss, Research, and Write As we progress through this unit for the next few days, you will read and discuss information about the possibility of life beyond earth. Listening and speaking skills will be practiced. Evaluating claims and supporting evidence will be a primary focus along with research and writing skills.
  3. 3. Before we can answer the question about life on other planets, we need to explore the origin of the universe.
  4. 4. Scientists generally agree that the universe began about 12.4 billion years ago with an explosive event called the big bang theory.
  5. 5. The Big Bang Theory asserts that before the universe existed, a tiny particle exploded and inflated at tremendous speed into matter that included protons and neutrons.
  6. 6. This exploding matter eventually created the galaxies containing stars and planets. As a result, stars and planets are composed of similar elements but in different quantities. What is our sun? How was it created? Read more to find out.
  7. 7. Our sun was created from star dust and gases in the universe about 5 billion years ago. The left over dust and gas revolved around the sun until gravity helped create the planets and their orbits.
  8. 8. The solar system is made up of eight planets-four with rocky, hard surfaces and four that are gas giants. Which two planets are closest to earth? Why do you think that one of these planets might have the best chance of all of the solar system planets to support life?
  9. 9. Planets are gas or terrestrial(rocky land) space objects that are larger than asteroids and orbit stars. They were created from left over star gas and dust that became round in shape as gravity acted on them during the orbiting process.
  10. 10. Understanding gravity is important in helping us understand the universe. Gravity moves objects with mass closer together. Larger objects with more mass have a stronger gravitational pull. The sun’s gravity pulls the planets into orbit. What would happen to us if the earth didn’t have any gravity?
  11. 11. The gravitational pull of our moon is what causes our ocean tides. If you were standing on the moon, would you be able to spin five times in the air and dunk a basketball even if you were a short person with limited athletic skill?
  12. 12. Examine the information below. What conclusion can you draw about the size of mars in relation to the size of Earth? What would you expect the gravity of the moon to be like?
  13. 13. Think about the impact gravity has on objects. Analyze these rocket speeds as each rocket leaves it’s planet. Consider the size of each planet in our solar system. Knowing that each rocket has the same power lift, what conclusion can you draw about the impact of gravity as it relates to objects?
  14. 14. As objects that contain metallic substances spin around, they create electrical charges that cause a magnetic field to form around the object. In space, these objects can be asteroids, planets, and stars. The Earth is like a giant magnet with north and south magnetic poles. As far as we know, most planets and stars have magnetic fields if they spin at a fast rate of speed. For example, Venus does not have a detectable magnetic field because it spins slowly.
  15. 15. Magnetic fields are possible when Electrons orbiting within an atom are unpaired and capable of aligning in an electric formation.
  16. 16. Over 100 years ago a brilliant scientist developed a revolutionary theory that helped the world understand how the universe works. Einstein’s theory of relativity went beyond the three dimensional realty that we see every day to a 4th dimension of time that is referred to as the time/space continuum.
  17. 17. Theoretically, one could one could go back in time or into the future since gravity is the consequence of the curvature of space/time caused by the uneven distribution of mass/energy.
  18. 18. With the 4th dimension in outer space, time warps and worm holes become interesting possibilities for forms of advanced life to travel throughout the universe to distant locations like earth. What are worm holes?
  19. 19. The theory of relativity demonstrates that all lines are curved in space. For example, the latitude and longitude lines actually curve as they cover the earth. Going faster than the speed of light could enable one to cross over into the future. Unfortunately, it is not possible for any object to exceed the speed of light.
  20. 20. Since the theory of relativity supports the possibilities of worm holes in time, we have to consider the chances that aliens could figure out ways to engage in time travel. Of course, any space traveler would have to beware of black holes capable of swallowing anything within their gravitational pull. Black holes remain invisible because they swallow all light and matter while performing like a magician who makes everything disappear.
  21. 21. Most of our planets have atmospheres with different kinds of gases. In total, our planets combine for 140 moons. Do you think life exists on any of these planets and moons? Why?
  22. 22. Four and a half billion years ago the earth and other planets in our solar system were formed from the left over dust and gasses after the sun was created.
  23. 23. Less than a 100 million years after the earth was formed, a giant meteor about the size of mars crashed into the earth and the material and dust that resulted formed the moon.
  24. 24. The newly created earth was extremely hot and inhospitable to life. However, after a billion years, the earth cooled and the gases in the atmosphere changed.
  25. 25. With a much cooler earth and all of the necessary elements, microscopic life was created about 3.5 billion yeas ago. Exactly what processes came together over millions of years to create the first cell is still a mystery to scientists. We do know that compounds rather than pure elements were needed in the process.
  26. 26. Which compound makes up over 65% of the human body? Which two elements are combined to create this compound?
  27. 27. Other compounds necessary in creating life include organic compounds such as carbohydrates, proteins, vitamins, and enzymes.
  28. 28. Although life as we know it requires approximately 25 different elements, the six elements that compose 95% of living organisms include carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.
  29. 29. In order for life to develop, it was necessary that the elements required for life be converted into cells with DNA capable of replicating.
  30. 30. The only way for the original cell to pass on the requirements for life to another cell was to have a structure with chromosomes and genes that could be inherited by the process of cell division. How long do you think it took for single cells to become human beings? What do scientists call this transition from lower forms of life to more advanced forms of life?
  31. 31. The evolution of life on earth flowed from elements to compounds to cells with DNA to humans. What does the word evolution mean?
  32. 32. It took approximately three and a half billion years for single cells to evolve into the early Homo sapien ancestors of modern man.
  33. 33. The first life on earth began in the ocean with the creation of microorganisms. Does this suggest that all living creatures are genetically related to fish? So, maybe mermaids really do exist(not).
  34. 34. It took several billion years for microscopic cells to evolve into giant reptiles. The first dinosaurs roamed the earth approximately 230 million years ago.
  35. 35. If the earliest giants of the earth were reptiles, where did mammals come from? Scientists believe that flying dinosaurs evolved into birds.
  36. 36. Over 100 million years ago a branch of reptiles begin to acquire characteristics that eventually evolved into our current idea of mammals. Fortunately for us, one type of mammal became similar to chimpanzees, our kissing cousins. Are humans really related to apes? Explain
  37. 37. Around 8 million years ago the ancestors of chimps evolved slowly into creatures that could walk upright until they began to resemble early man. What kind of evidence do you think supports the idea that humans evolved from chimpanzees?
  38. 38. The human genome contains 96% of the same genes found in chimpanzees. This means that we have nearly all of the genetic blueprints and DNA sequences found in chimps and their close relatives.
  39. 39. Watch this one minute animated illustration of the evolution from microscopic organism to human being. This process took millions of years. Where does this video suggest that life began? Can you retell the story of evolution after watching this video clip?
  40. 40. If life could evolve on earth, is it reasonable to assume that life could evolve somewhere else in the universe? Why? Or Why not?
  41. 41. Is it likely that advanced forms of life know about us but are not interested in visiting us at this point? Why might that be the case?
  42. 42. Do you believe people who say they have been kidnapped and taken for rides in alien spaceships? Why? Why not?
  43. 43. Our modern civilization has undergone tremendous advancements in technology that have enabled our world to explore other worlds. What were some of these important technological advancements?
  44. 44. Three and a half billion years after the beginning of life on earth, the United States used rocket technology to reach the moon.
  45. 45. By 1968, the United States used the Apollo 8 mission to achieve the first manned space flight to orbit the moon. Did we find any evidence that life existed on the moon?
  46. 46. In 1969, American astronauts walked on the moon for the first time in history. During the next three years, the United States had five more manned landings on the moon.
  47. 47. Scientists have determined that the mineral composition of the moon closely matches that of earth. This fact alone, is more evidence that the moon is composed of material derived from earth. Unfortunately, we have not found evidence of life on the moon.
  48. 48. After putting a man on the moon in 1969, the United States turned its space exploration toward mars. Why do you think we chose to investigate mars rather than other planets?
  49. 49. Mars is a planet that holds promise for the existence of life. It has a very cold surface with polar ice caps, seasons, volcanoes, and canyons. It is also a very close neighbor to earth.
  50. 50. The United States has been exploring the surface of mars for over forty years with robots called rovers. As a result, it has been determined that mars has clear evidence of water. There are definite signs of ancient floods. The existence of water is crucial since scientists believe it is necessary to sustain life.
  51. 51. In 1971, the United States sent Mariner 9 to be the first space craft to orbit mars. By 1976, Viking 1 landed on mars with a rover capable of taking photographs.
  52. 52. During the last couple of years, our space program has been collecting important samples of materials below the surface of the red planet. Scientists are hoping to find evidence that mars either has some form of life or has supported life in the past.
  53. 53. We have explored parts of our solar system in search of alien life forms. What are the chances that we will find evidence of life on planets or moons in our solar system? What kind of evidence would persuade you that life has existed elsewhere in our solar system?
  54. 54. Will we find life anywhere in the universe other than Earth? Life as we know it requires water, carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur.
  55. 55. Scientists have concluded that all life on earth evolved from the same original cell that ignited the creation of life over 3.5 billions years ago. Significantly, there has not been any creation of life on our planet except life that has evolved from the original first cell. So for the last 3.5 billion years life was created just one time. What does this suggest about the likelihood of life being created on other planets?
  56. 56. Another factor that scientists use to evaluate the probability of life beyond earth is the number of planets that exist in the habitable zone around stars. Only a small fraction of planets are located in these desirable zones around stars. Why do you think that scientists created a prediction model that uses habitable zones for their estimates of life?
  57. 57. Astronomers like to use the Drake Equation as a tool to predict the odds of finding intelligent life beyond our earth. This equation uses multiple factors to estimate the chances of extraterrestrial life. There appears to be at least 100 to 200 billion planets in our milky way galaxy and scientists estimate that billions of these planets have what will be necessary for life as we know it. Therefore, it is probable that billions of planets in our galaxy have the prerequisites for life. Consider this large number and factor in the latest estimate of how many galaxies may be in the universe and the number becomes immense. Most scientists believe the universe may have as many as two trillion galaxies. What can you conclude from reading this paragraph?
  58. 58. Can we be sure that life was spawned on earth rather than transported here by an advanced alien civilization? Some scientists support the directed panspermia theory which proposes that advanced civilizations brought life to earth as an experiment. Others suggest that life could have been brought from outer space accidentally on a meteorite. What do you think about these theories?
  59. 59. If life exists beyond earth, what might it look like? What forms of life might we discover on other planets or solar systems?
  60. 60. Draw a sketch of a possible example of an alien from outer space. Share your drawing with the class.
  61. 61. Do you really believe that aliens will look like us? If these are real forms of life on earth today, what can we expect life to look like on other planets?
  62. 62. Is it likely that aliens from outer space have visited earth? What kind of evidence would prove the existence of aliens?
  63. 63. Do you think that aliens are probably far more advanced than we are? Or, do you expect life on other planets to be more primitive than life on Earth? Why?
  64. 64. Some people believe that unusual phenomena from our distant past is evidence that we have been visited by aliens from outer space. Ancient drawings that show space craft may suggest that aliens have been to earth.
  65. 65. Etched into a high plateau in Peru’s Nazca Desert, a series of ancient designs raise serious questions about who created them. Some ancient alien theorists claim that since the Nazca drawings are so huge and can only be viewed clearly from the sky, they must have been drawn by aliens from outer space who visited two thousand years ago.
  66. 66. The Nazca designs in Peru extend for over 50 miles and include simple , geometric lines depicting animals, birds, and humans. Some of the creations measure more than 600 feet across.
  67. 67. About two thousand years ago in India, ancient drawings were made on large stones. These drawings included a variety of flying machines called vimanas. Some alien theorists suggest that these drawings are of alien space craft that visited our world in the past.
  68. 68. On a small island off of the west coast of South America there is another unexplainable phenomena. Easter Island is the home to over 880 enormous stone statues carved with human features. The largest stones are up to 33 feet tall and weigh up to 75 tons.
  69. 69. Some people have suggested that these incredibly huge statues are too big to have been carved and moved by humans. They suggest that ancient alien visitors must have created them. Other experts say that the ancient Polynesians figured out a special way to move the stones.
  70. 70. So the question remains the same. Do we have enough supportable evidence that life exists beyond our earth?
  71. 71. It is important to know that life on this planet is a form of carbon chemistry. It starts with photosynthesis which takes carbon dioxide and water and makes it into complicated compounds which get incorporated into living things. It continues with DNA which enables cells to replicate themselves.
  72. 72. Carbon is abundant throughout the universe. It is one of the most common elements produced in stars. All forms of life ever encountered on earth require carbon. Thus, carbon chemistry is most likely the basis for any life forms elsewhere. What happens when you burn anything that was originally alive? Will you get the same result by burning newspapers and dead animals? Explain
  73. 73. In 1994, while digging through the Antarctic ice, scientists discovered a meteorite that was determined to be from mars. After several years of scientific analysis and debate, scientists agreed that the meteorite did not contain any materials that suggested the possibility of life. However, we continue to explore more areas of mars for any signs of life.
  74. 74. In addition to mars, Jupiter’s moons have provided new places to search for life. Several of the moons that orbit Jupiter appear to have suitable environments for living organisms.
  75. 75. Europa is the best candidate of the moons around Jupiter to provide clues as to the existence of life beyond earth in our solar system.
  76. 76. We know that the vast majority of planets in the universe have extreme climatic conditions that preclude life as we know it.
  77. 77. But there are many planets in the universe that could support life as we know it.
  78. 78. This sulfuric lake contains microscopic life. If life on Earth can thrive in chemical lakes like these, it may exist on distant planets.
  79. 79. What might alien life look like? Can you describe some possibilities?
  80. 80. Have You Ever Seen One of These? Well, they live right here on Earth.
  81. 81. Could these newly discovered creatures on Earth be like life on other planets?
  82. 82. Maybe these fellows aren’t so weird!
  83. 83. Read the following two articles about the possibility of finding life beyond our own earth. As you read these articles, identify and record any claims or logical arguments that support the pro and con position about the likelihood of finding life on another planet. You will use your notes to write an argumentative essay about finding alien life forms in the universe.
  84. 84. An Argument for Life on Other Planets The number of stars in our galaxy are around 200 billion. Also used in the equation is the number of stars that would have planetary systems, how many of those planets could support life, and on how many of those planets would life evolve, with an intelligent life.
  85. 85. Our space program and those of other nations have been for several years, sending probes out into our solar system, and among other things being accomplished, they are looking for other life on those adjacent planets to ours. The Hubble telescope has given us glimpses at objects that a few years ago no one dreamed we'd ever be able to see. I think many of us would like to know (and probably even hope), that we are not the only living thing in the universe. What is the author hoping for?
  86. 86. Our knowledge is so limited however, that we are still searching our closest neighbor for that information. I'm not implying that we haven't had success in some of our ventures, but when you think of the possibility that there may be 200 Billion stars just in our galaxy, according to Drake's equation, surely some of which can have planets similar (or not similar) to ours, the odds are pretty high for finding other life forms. The author claims that the odds for finding planets with life are pretty high. What evidence does the author provide to support this claim?
  87. 87. I envy those being born today for what they may learn in their lifetime, while on the other hand, I hope that we leave that opportunity for them to learn. Technology is proceeding forward at a faster rate than it ever has in our existence on this planet. Why does the author envy younger people?
  88. 88. • Some researchers indicate that our planet earth is about 4.6 billion years old. The oldest known direct evidence of life on earth is a fossilized bacteria found in 3.5 billion- year-old rocks from Western Australia, as announced by J. William Schopf of the University of California at Los Angeles in 1993. The technology we enjoy today has only been developed in the past 100 years, so can we imagine what will be forthcoming in the next 100 years? • What is the author suggesting about the rate of future discoveries?
  89. 89. We are unique in the location of our planet within our solar system and galaxy, which surely had a vital affect on it being habitable. What we have developed into has been our choice. What we leave for our children and grandchildren is also our choice. I hope we make the right decisions. What is the author implying about humans and their use of the planet?
  90. 90. Life on Saturn’s Moons: Enceladus, Titan, and Jupiter’s Europa? Understanding the oddities of life in our most extreme regions leads us to wonder: Is life on Enceladus, Titan, or Europa possible?
  91. 91. Enceladus is the brightest moon in our solar system. It is composed entirely of ice, fully reflecting light. In 2005, the Cassini spacecraft photographed geysers of ice and water vapor being expelled at least 300km into space, so there must be liquid water under the moon’s icy surface, and sufficient heat internally to propel ice into water vapor. Why is the author optimistic about the possibility of the moon, Enceladus, high a chance for life?
  92. 92. Titan is the only moon in our Solar System that has a substantial atmosphere (it is mostly nitrogen). When the Cassini spacecraft dropped the Huygens probe into Titan’s atmosphere, the probe found ammonia and methane. Lakes of methane are clearly visible, as you can see from the image above. Ammonia and methane could theoretically combine, in an electrically charged environment, to make organic compounds, and extremophile bacteria similar to those found in deep ocean hot springs on Earth. It would seem that extremophile bacteria could survive in this methanological system. Why does the author think that the discovery of ammonia and methane are positive indications for finding life?
  93. 93. Europa, the second moon of Jupiter, has an icy surface with a suspected liquid ocean below the surface. Life similar to that of subglacial regions is possible on Europa as well.
  94. 94. Stephen Hawking, Renowned Scientist Life in the Universe • What are the chances that we will encounter some alien form of life as we explore the galaxy? If the argument about the time scale for the appearance of life on Earth is correct, there ought to be many other stars whose planets have life on them. Some of these stellar systems could have formed 5 billion years before the Earth. So why is the galaxy not crawling with self designing mechanical or biological life forms? • What does the author mean by self designing mechanical life forms?
  95. 95. • Why hasn't the Earth been visited, and even colonized. I discount suggestions that UFO's contain beings from outer space. I think any visits by aliens would be much more obvious, and probably also, much more unpleasant. • Does the author believe that earth has been visited by aliens? Why or why not?
  96. 96. • What is the explanation of why we have not been visited? One possibility is that the argument about the appearance of life on Earth is wrong. Maybe the probability of life spontaneously appearing is so low that Earth is the only planet in the galaxy, or in the observable universe, in which it happened.
  97. 97. • Another possibility is that there was a reasonable probability of forming self reproducing systems, like cells, but that most of these forms of life did not evolve intelligence. We are used to thinking of intelligent life, as an inevitable consequence of evolution. But the Anthropic Principle should warn us to be wary of such arguments. It is more likely that evolution is a random process, with intelligence as only one of a large number of possible outcomes. •Why does the author think that finding intelligent life may be a remote possibility?
  98. 98. • It is not clear that intelligence has any long-term survival value. Bacteria, and other single cell organisms, will live on, if all other life on Earth is wiped out by our actions. There is support for the view that intelligence, was an unlikely development for life on Earth, from the chronology of evolution. • What does the author believe about finding intelligent life beyond Earth?
  99. 99. • It took a very long time, two and a half billion years, to go from single cells to multi-cell beings, which are a necessary precursor to intelligence. This is a good fraction of the total time available, before the Sun blows up. So it would be consistent with the hypothesis that the probability for life to develop intelligence is low. In this case, we might expect to find many other life forms in the galaxy, but we are unlikely to find intelligent life. •What is the conclusion reached by this author? What argument does the author use to support this conclusion?
  100. 100. • Another way, in which life could fail to develop to an intelligent stage, would be if an asteroid or comet were to collide with the planet. We have just observed the collision of a comet, Schumacher-Levi, with Jupiter. It produced a series of enormous fireballs. It is thought the collision of a rather smaller body with the Earth, about 70 million years ago, was responsible for the extinction of the dinosaurs. A few small early mammals survived, but anything as large as a human, would have almost certainly been wiped out. It is difficult to say how often such collisions occur, but a reasonable guess might be every twenty million years, on average. What does the author suggest as to why some planets may have had intelligent life in the past, but no longer have it?
  101. 101. • If this figure is correct, it would mean that intelligent life on Earth has developed only because of the lucky chance that there have been no major collisions in the last 70 million years. Other planets in the galaxy, on which life has developed, may not have had a long enough collision free period to evolve intelligent beings. •What does the author suggest as a possible block to finding intelligent life?
  102. 102. • A third possibility is that there is a reasonable probability for life to form, and to evolve to intelligent beings, in the external transmission phase. But at that point, the system becomes unstable, and the intelligent life destroys itself. This would be a very pessimistic conclusion. I very much hope it isn't true. I prefer a fourth possibility: there are other forms of intelligent life out there, but that we have been overlooked. There used to be a project called SETI, the search for extra- terrestrial intelligence. •Why does the author think that there may be intelligent life in the universe but we have never been contacted by them?
  103. 103. • It involved scanning the radio frequencies, to see if we could pick up signals from alien civilizations. I thought this project was worth supporting, though it was cancelled due to a lack of funds. But we should have been wary of answering back, until we have developed a bit further. Meeting a more advanced civilization, at our present stage, might be a bit like the original inhabitants of America meeting Columbus. I don't think they were better off for it. • What does the author suggest as a reason why we should be careful about responding to possible alien communication?
  104. 104. What are the chances of life on another planet? May 9, 2016 •In an infinite universe, most scientists agree, the odds of life existing on a planet besides Earth are pretty high. It is unlikely, however, that familiar life forms will be found on any planet within our solar system.
  105. 105. • Life as we know it—everything from single-celled organisms to human beings—consists largely of liquid water. So a planet that harbors life can't be too cold or water will freeze, nor can it be too hot or all the water will evaporate. Planets closer to the sun than Earth are too hot, and those farther away are too cold. The surface of Venus, for example, is hot enough to melt lead, and would vaporize any living thing, while the surface of Mars is frozen solid. •What reasons does the author offer as to why he believes that finding life beyond Earth in our solar system is unlikely?
  106. 106. • Life as we know it here on Earth also requires a magnetic field and an atmosphere, both of which protect it from the lethal radiation our parent star, the sun, emits. Earth's magnetic field—generated by its rotating iron core—deflects the solar wind, a continuous stream of high-speed, high-energy particles coming out of the sun. (As those particles careen by the edges of Earth's atmosphere, they sometime create the phenomenon we call the Northern Lights.) Without the magnetic field there, the solar wind might destroy all life on Earth. •Why does the author indicate that a magnetic field would be necessary if a planet were to sustain life?
  107. 107. • As for Earth's atmosphere, it protects life because the water, carbon dioxide and other gases in it absorb solar radiation in its harmful ultraviolet-light form. The parent stars of other solar systems would emit radiation as well, and the planets orbiting them would need the same kind of protection. • Why would an atmosphere be important for a planet with life?
  108. 108. • Of course, life on Earth also alters the chemical composition of the atmosphere—Earth's atmosphere lacked gaseous oxygen until plants started growing here some million years ago. So molecules like oxygen in the atmosphere of another planet would be one indication—not proof—that there are living things there. •What does the author suggest might increase the odds of finding life on a planet?
  109. 109. • Scientists have been studying the planets of our own solar system for more than 50 years, looking for evidence of past or present life, among other things. Launched in 1967, the Soviet Union's Venera 4 was the first probe known to land on and send back data from another planet. The mission revealed that Venus' famously soupy atmosphere is made up almost entirely of carbon dioxide with a surface temperature hot enough to melt lead, making it a very unlikely place to harbor life. •Why has Venus been ruled out as a planet that might have life?
  110. 110. • Today, NASA's Mars rover, Opportunity, has been sending back reams of data about the red planet since it landed there 12 years ago. Living well past all expectations, Opportunity not only transmits landscape photos and the occasional tweet, but also collects and analyzes soil and atmosphere samples. It's been an invaluable research tool, but has found no direct evidence that life ever existed on Mars, and has revealed that the planet's atmosphere is too thin to protect it from the sun's radiation. •According to the author, should we be optimistic or pessimistic about life on Mars?
  111. 111. • The discovery of thousands of planets orbiting nearby stars has nevertheless greatly increased speculation that there may be some kind of life on a planet outside our solar system. In the past 20 years, we have confirmed the discovery of almost 2,000 planets, called exoplanets, beyond our solar system. Four thousand other exoplanet candidates await confirmation. •What are exoplanets?
  112. 112. • The ones most likely to harbor life would be smallish, rocky planets like Earth. Larger planets tend to be composed of hydrogen gas, the most abundant element in the universe, and to not have a solid surface. Good candidates for life would also occupy what scientists call the habitable zone—the zone in which a planet's distance from the parent star makes liquid water possible. •According to the author, what is the habitable zone?
  113. 113. • The Kepler mission—a space observatory launched by NASA in 1997 to search our galaxy for just these kinds of Earth-like planets—has found one candidate that meets both requirements, Kepler-452b. So the chances of life on another planet are high. However, we have no direct evidence yet of life anywhere other than Earth. •What was the Kepler mission and why was it important?
  114. 114. • The real question is, will we ever find the planet we're looking for, given that we'll have to survey the planetary systems of the universe's estimated 1 billion trillion stars? And if we do find that planet, will we even recognize the life it harbors? There's no real reason why we should expect to discover life as we know it orbiting a star many light years away from our home solar system. There's so much we don't know that we are severely limited in our ability to even think about the question. • According to the paragraph, why does the author have doubts about finding life elsewhere in the universe? • Read more at:
  115. 115. Group Discussion Meet in groups and discuss the following. • 1. What are some of the reasons that support the idea that life as we know it exists somewhere in the universe other than the planet Earth. • 2. What are some of the reasons that suggest that life on other planets will not be discovered any time soon and maybe not at all. • 3. What kind of materials or conditions are probably necessary for life to develop on other planets?
  116. 116. Prepare to Write Write a pro and con essay discussing the probability of life on other planets. Include a description of the materials and conditions necessary for life as we know it. Review the development of life on earth and how it might support the idea that life can or cannot exist else where in the universe.
  117. 117. Research Websites • 1. • 2. • 3. • 4. • 5. • 6.