full transcript

From the Ted Talk by Zachary Metz: Where did Earth's water come from?

Unscramble the Blue Letters


But there's a big quoesitn that we don't have the answer to: how much water arrived on Earth, and when? If, as one theory goes, relatively small amounts of wetar were present on Earth when the rock formed, the high temperatures and lack of any sodnnuiurrg atmosphere would have caused it to evaporate back into space. Water would have been unable to remain on the planet until hneuddrs of millions of years later when our first atmosphere formed through a prosces cellad outgassing. This occurred when molten rock in the Earth's core released volcanic gasses to the surface, creating a layer that could then trap escaping water. So how then did water get back to the panlet? Scientists have long suspected that much of it was brought by ice-bearing ctoems, or more likely asteroids that bombarded the Earth over millions of years. Recent research has challenged this theory. In examining carbonaceous cndrhoite meterorites that feomrd shorty after the birth of our solar system, scientists have found that not only did they contain water, but their mineral chemical composition matched rocks on etrah and saeplms from an asteroid that formed at the same time as our planet. This suggests that the Earth may have accumulated a ssautnaitbl amount of water early on that was able to stay put, despite the lack of an apsortehme, though asteroids may have brought more over the eons. If this turns out to be true, life may have formed much earlier than previously thought.

Open Cloze


But there's a big ________ that we don't have the answer to: how much water arrived on Earth, and when? If, as one theory goes, relatively small amounts of _____ were present on Earth when the rock formed, the high temperatures and lack of any ___________ atmosphere would have caused it to evaporate back into space. Water would have been unable to remain on the planet until ________ of millions of years later when our first atmosphere formed through a _______ ______ outgassing. This occurred when molten rock in the Earth's core released volcanic gasses to the surface, creating a layer that could then trap escaping water. So how then did water get back to the ______? Scientists have long suspected that much of it was brought by ice-bearing ______, or more likely asteroids that bombarded the Earth over millions of years. Recent research has challenged this theory. In examining carbonaceous _________ meterorites that ______ shorty after the birth of our solar system, scientists have found that not only did they contain water, but their mineral chemical composition matched rocks on _____ and _______ from an asteroid that formed at the same time as our planet. This suggests that the Earth may have accumulated a ___________ amount of water early on that was able to stay put, despite the lack of an __________, though asteroids may have brought more over the eons. If this turns out to be true, life may have formed much earlier than previously thought.

Solution


  1. samples
  2. called
  3. earth
  4. question
  5. planet
  6. process
  7. chondrite
  8. substantial
  9. atmosphere
  10. comets
  11. surrounding
  12. water
  13. hundreds
  14. formed

Original Text


But there's a big question that we don't have the answer to: how much water arrived on Earth, and when? If, as one theory goes, relatively small amounts of water were present on Earth when the rock formed, the high temperatures and lack of any surrounding atmosphere would have caused it to evaporate back into space. Water would have been unable to remain on the planet until hundreds of millions of years later when our first atmosphere formed through a process called outgassing. This occurred when molten rock in the Earth's core released volcanic gasses to the surface, creating a layer that could then trap escaping water. So how then did water get back to the planet? Scientists have long suspected that much of it was brought by ice-bearing comets, or more likely asteroids that bombarded the Earth over millions of years. Recent research has challenged this theory. In examining carbonaceous chondrite meterorites that formed shorty after the birth of our solar system, scientists have found that not only did they contain water, but their mineral chemical composition matched rocks on Earth and samples from an asteroid that formed at the same time as our planet. This suggests that the Earth may have accumulated a substantial amount of water early on that was able to stay put, despite the lack of an atmosphere, though asteroids may have brought more over the eons. If this turns out to be true, life may have formed much earlier than previously thought.

Frequently Occurring Word Combinations




Important Words


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  2. amount
  3. amounts
  4. answer
  5. arrived
  6. asteroid
  7. asteroids
  8. atmosphere
  9. big
  10. birth
  11. bombarded
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  14. carbonaceous
  15. caused
  16. challenged
  17. chemical
  18. chondrite
  19. comets
  20. composition
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  26. eons
  27. escaping
  28. evaporate
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  30. formed
  31. gasses
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  35. layer
  36. life
  37. long
  38. matched
  39. meterorites
  40. millions
  41. mineral
  42. molten
  43. occurred
  44. outgassing
  45. planet
  46. present
  47. previously
  48. process
  49. put
  50. question
  51. released
  52. remain
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  54. rock
  55. rocks
  56. samples
  57. scientists
  58. shorty
  59. small
  60. solar
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  64. suggests
  65. surface
  66. surrounding
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  68. system
  69. temperatures
  70. theory
  71. thought
  72. time
  73. trap
  74. true
  75. turns
  76. unable
  77. volcanic
  78. water
  79. years