full transcript

From the Ted Talk by Roey Tzezana: Could human civilization spread across the whole galaxy?

Unscramble the Blue Letters

Could human coiiivtalizn eventually spread across the whole Milky Way galaxy? Could we move beyond our small blue planet to establish colonies in the multitude of star systems out there? This question's a pretty daunting one. There are around 300 billion srats in the galaxy, which is about 160,000 light-years across. So far we've sent a single safercacpt outside our solar stseym, trudging along at 0.006% of the speed of light. At that rate, it would take over 2.5 billion years just to get from one end of the galaxy to the other. And then there's the qitesoun of human survival. The gulf between stars is simply enormous. We couldn't live sustainably on most planets, and we require a lot of resources to stay alive. And yet, decades ago, scholars found that it's theoretically possible to not just spread human civilization across the galaxy, but to do so quite qukcily, without breaking any known laws of physics. Their idea is based on the work of a mathematician named John von Neumann, who dneegisd on paper machines that could self-replicate and create new generations of themselves. These would later come to be known as von Neumann machines. In the context of space exploration, von Neumann machines could be built on Earth and lchaneud into spcae. There, the self-sufficient machines would land on distant ptleans. They would then mine the available resources and harvest ergeny, build replicas of themselves, laucnh those to the nearest planets, and continue the cclye. The result is the creation of millions of probes spreading outwards into the universe like a drop of ink in a fishbowl. srhcloas crunched the numbers and found that a single von nuamnen mcinhae traveling at 5% of the speed of light should be able to replicate throughout our gaxaly in 4 million years or less. That may sound like a long time, but when you consider that our unisvree is 14 billion yreas old, on a cosmic scale, it's incredibly fast - the equivalent of about 2.5 hours in an entire year. Creating von Neumann machines would rerquie a few technologies we don't have yet, including aeacvndd aftairciil intelligence, mariouiaitntzin, and better propulsion systems. If we wanted to use them to saeprd actual humans throughout the galaxy, we would need yet another technological leap - the ability to artificially grow biological osnirgmas and bodies using raw elements and genetic information. Regardless, if in the last billion years an alien civilization created such a machine and set it multiplying its way toward us, our galaxy would be swarming with them by now. So then where are all these machines? Some astronomers, like Carl Sagan, say that intelligent aliens wouldn't build self-replicating micaenhs at all. They might hurtle out of control, scavenging planets to their cores in order to keep replicating. Others take the machines absence as proof that intelligent alien civilizations don't exist, or that they go ecnxitt before they can develop the necessary technologies. But all this hasn't stopped people from imagining what it would be like if they were out there. Science fiction author David Brin writes about a universe in which many different von Neumann machines exist and plfrioraete simultaneously. Some are designed to greet ynoug civilizations, others to locate and doresty them before they become a threat. In fact, in Brin's story "Lungfish," some von Neumann machines are keeping a close wtcah over the Earth right now, waiting for us to reach a certain level of sspthtciiiaoon before they make their move. For now, all we have is curiosity and theory. But the next time you look at the night sky, consider that billions of self-replicating machines could be advancing between stars in our galaxy right now. If they exist, one of them will eventually land on Earth, or maybe, just maybe, they're already here.

Open Cloze

Could human ____________ eventually spread across the whole Milky Way galaxy? Could we move beyond our small blue planet to establish colonies in the multitude of star systems out there? This question's a pretty daunting one. There are around 300 billion _____ in the galaxy, which is about 160,000 light-years across. So far we've sent a single __________ outside our solar ______, trudging along at 0.006% of the speed of light. At that rate, it would take over 2.5 billion years just to get from one end of the galaxy to the other. And then there's the ________ of human survival. The gulf between stars is simply enormous. We couldn't live sustainably on most planets, and we require a lot of resources to stay alive. And yet, decades ago, scholars found that it's theoretically possible to not just spread human civilization across the galaxy, but to do so quite _______, without breaking any known laws of physics. Their idea is based on the work of a mathematician named John von Neumann, who ________ on paper machines that could self-replicate and create new generations of themselves. These would later come to be known as von Neumann machines. In the context of space exploration, von Neumann machines could be built on Earth and ________ into _____. There, the self-sufficient machines would land on distant _______. They would then mine the available resources and harvest ______, build replicas of themselves, ______ those to the nearest planets, and continue the _____. The result is the creation of millions of probes spreading outwards into the universe like a drop of ink in a fishbowl. ________ crunched the numbers and found that a single von _______ _______ traveling at 5% of the speed of light should be able to replicate throughout our ______ in 4 million years or less. That may sound like a long time, but when you consider that our ________ is 14 billion _____ old, on a cosmic scale, it's incredibly fast - the equivalent of about 2.5 hours in an entire year. Creating von Neumann machines would _______ a few technologies we don't have yet, including ________ __________ intelligence, _______________, and better propulsion systems. If we wanted to use them to ______ actual humans throughout the galaxy, we would need yet another technological leap - the ability to artificially grow biological _________ and bodies using raw elements and genetic information. Regardless, if in the last billion years an alien civilization created such a machine and set it multiplying its way toward us, our galaxy would be swarming with them by now. So then where are all these machines? Some astronomers, like Carl Sagan, say that intelligent aliens wouldn't build self-replicating ________ at all. They might hurtle out of control, scavenging planets to their cores in order to keep replicating. Others take the machines absence as proof that intelligent alien civilizations don't exist, or that they go _______ before they can develop the necessary technologies. But all this hasn't stopped people from imagining what it would be like if they were out there. Science fiction author David Brin writes about a universe in which many different von Neumann machines exist and ___________ simultaneously. Some are designed to greet _____ civilizations, others to locate and _______ them before they become a threat. In fact, in Brin's story "Lungfish," some von Neumann machines are keeping a close _____ over the Earth right now, waiting for us to reach a certain level of ______________ before they make their move. For now, all we have is curiosity and theory. But the next time you look at the night sky, consider that billions of self-replicating machines could be advancing between stars in our galaxy right now. If they exist, one of them will eventually land on Earth, or maybe, just maybe, they're already here.

Solution

  1. universe
  2. launch
  3. stars
  4. proliferate
  5. civilization
  6. destroy
  7. young
  8. scholars
  9. cycle
  10. planets
  11. machines
  12. designed
  13. space
  14. require
  15. sophistication
  16. artificial
  17. galaxy
  18. years
  19. energy
  20. spacecraft
  21. neumann
  22. organisms
  23. spread
  24. advanced
  25. miniaturization
  26. system
  27. launched
  28. quickly
  29. machine
  30. question
  31. watch
  32. extinct

Original Text

Could human civilization eventually spread across the whole Milky Way galaxy? Could we move beyond our small blue planet to establish colonies in the multitude of star systems out there? This question's a pretty daunting one. There are around 300 billion stars in the galaxy, which is about 160,000 light-years across. So far we've sent a single spacecraft outside our solar system, trudging along at 0.006% of the speed of light. At that rate, it would take over 2.5 billion years just to get from one end of the galaxy to the other. And then there's the question of human survival. The gulf between stars is simply enormous. We couldn't live sustainably on most planets, and we require a lot of resources to stay alive. And yet, decades ago, scholars found that it's theoretically possible to not just spread human civilization across the galaxy, but to do so quite quickly, without breaking any known laws of physics. Their idea is based on the work of a mathematician named John von Neumann, who designed on paper machines that could self-replicate and create new generations of themselves. These would later come to be known as von Neumann machines. In the context of space exploration, von Neumann machines could be built on Earth and launched into space. There, the self-sufficient machines would land on distant planets. They would then mine the available resources and harvest energy, build replicas of themselves, launch those to the nearest planets, and continue the cycle. The result is the creation of millions of probes spreading outwards into the universe like a drop of ink in a fishbowl. Scholars crunched the numbers and found that a single von Neumann machine traveling at 5% of the speed of light should be able to replicate throughout our galaxy in 4 million years or less. That may sound like a long time, but when you consider that our universe is 14 billion years old, on a cosmic scale, it's incredibly fast - the equivalent of about 2.5 hours in an entire year. Creating von Neumann machines would require a few technologies we don't have yet, including advanced artificial intelligence, miniaturization, and better propulsion systems. If we wanted to use them to spread actual humans throughout the galaxy, we would need yet another technological leap - the ability to artificially grow biological organisms and bodies using raw elements and genetic information. Regardless, if in the last billion years an alien civilization created such a machine and set it multiplying its way toward us, our galaxy would be swarming with them by now. So then where are all these machines? Some astronomers, like Carl Sagan, say that intelligent aliens wouldn't build self-replicating machines at all. They might hurtle out of control, scavenging planets to their cores in order to keep replicating. Others take the machines absence as proof that intelligent alien civilizations don't exist, or that they go extinct before they can develop the necessary technologies. But all this hasn't stopped people from imagining what it would be like if they were out there. Science fiction author David Brin writes about a universe in which many different von Neumann machines exist and proliferate simultaneously. Some are designed to greet young civilizations, others to locate and destroy them before they become a threat. In fact, in Brin's story "Lungfish," some von Neumann machines are keeping a close watch over the Earth right now, waiting for us to reach a certain level of sophistication before they make their move. For now, all we have is curiosity and theory. But the next time you look at the night sky, consider that billions of self-replicating machines could be advancing between stars in our galaxy right now. If they exist, one of them will eventually land on Earth, or maybe, just maybe, they're already here.

Frequently Occurring Word Combinations

ngrams of length 2

collocation frequency
von neumann 6
neumann machines 5
billion years 3
human civilization 2

ngrams of length 3

collocation frequency
von neumann machines 5

Important Words

  1. ability
  2. absence
  3. actual
  4. advanced
  5. advancing
  6. alien
  7. aliens
  8. alive
  9. artificial
  10. artificially
  11. astronomers
  12. author
  13. based
  14. billion
  15. billions
  16. biological
  17. blue
  18. bodies
  19. breaking
  20. brin
  21. build
  22. built
  23. carl
  24. civilization
  25. civilizations
  26. close
  27. colonies
  28. context
  29. continue
  30. control
  31. cores
  32. cosmic
  33. create
  34. created
  35. creating
  36. creation
  37. crunched
  38. curiosity
  39. cycle
  40. daunting
  41. david
  42. decades
  43. designed
  44. destroy
  45. develop
  46. distant
  47. drop
  48. earth
  49. elements
  50. energy
  51. enormous
  52. entire
  53. equivalent
  54. establish
  55. eventually
  56. exist
  57. exploration
  58. extinct
  59. fact
  60. fast
  61. fiction
  62. fishbowl
  63. galaxy
  64. generations
  65. genetic
  66. greet
  67. grow
  68. gulf
  69. harvest
  70. hours
  71. human
  72. humans
  73. hurtle
  74. idea
  75. imagining
  76. including
  77. incredibly
  78. information
  79. ink
  80. intelligence
  81. intelligent
  82. john
  83. keeping
  84. land
  85. launch
  86. launched
  87. laws
  88. leap
  89. level
  90. light
  91. live
  92. locate
  93. long
  94. lot
  95. machine
  96. machines
  97. mathematician
  98. milky
  99. million
  100. millions
  101. miniaturization
  102. move
  103. multiplying
  104. multitude
  105. named
  106. nearest
  107. neumann
  108. night
  109. numbers
  110. order
  111. organisms
  112. outwards
  113. paper
  114. people
  115. physics
  116. planet
  117. planets
  118. pretty
  119. probes
  120. proliferate
  121. proof
  122. propulsion
  123. question
  124. quickly
  125. rate
  126. raw
  127. reach
  128. replicas
  129. replicate
  130. replicating
  131. require
  132. resources
  133. result
  134. sagan
  135. scale
  136. scavenging
  137. scholars
  138. science
  139. set
  140. simply
  141. simultaneously
  142. single
  143. sky
  144. small
  145. solar
  146. sophistication
  147. sound
  148. space
  149. spacecraft
  150. speed
  151. spread
  152. spreading
  153. star
  154. stars
  155. stay
  156. stopped
  157. story
  158. survival
  159. sustainably
  160. swarming
  161. system
  162. systems
  163. technological
  164. technologies
  165. theoretically
  166. theory
  167. threat
  168. time
  169. traveling
  170. trudging
  171. universe
  172. von
  173. waiting
  174. wanted
  175. watch
  176. work
  177. writes
  178. year
  179. years
  180. young