full transcript

From the Ted Talk by Daniel Finkel: Can you solve the dark matter fuel riddle?

Unscramble the Blue Letters


There’s an interesting pattern that can help. At the start you have exactly 3 tanks’ wtroh of fuel. At 8 parsecs you need exactly 1. Is there a point, which we can call ponit X, where you could have exactly 2? That would be useful, because then you could refuel there exactly twice, manikg full use of your stgoare ccaaptiy without any waste.

Wherever point X is, you’ll jump forward from it twice: once to deposit some fuel at the 8-parsec cache point, and a second time for good. So you’ll jump the distance between X and 8-parsecs 3 times in all. You’d have 2 tanks of fuel at point X, and need 1 left at the 8 parsec cache point, so you can spend one tank— or 15 units— going back and forth. Since 15 units divided by 3 trips is 5, we can place these two cache points 5 parsecs apart. Any farther, and you wouldn’t have enough fuel to reach the alien space station.

Open Cloze


There’s an interesting pattern that can help. At the start you have exactly 3 tanks’ _____ of fuel. At 8 parsecs you need exactly 1. Is there a point, which we can call _____ X, where you could have exactly 2? That would be useful, because then you could refuel there exactly twice, ______ full use of your _______ ________ without any waste.

Wherever point X is, you’ll jump forward from it twice: once to deposit some fuel at the 8-parsec cache point, and a second time for good. So you’ll jump the distance between X and 8-parsecs 3 times in all. You’d have 2 tanks of fuel at point X, and need 1 left at the 8 parsec cache point, so you can spend one tank— or 15 units— going back and forth. Since 15 units divided by 3 trips is 5, we can place these two cache points 5 parsecs apart. Any farther, and you wouldn’t have enough fuel to reach the alien space station.

Solution


  1. capacity
  2. storage
  3. point
  4. worth
  5. making

Original Text


There’s an interesting pattern that can help. At the start you have exactly 3 tanks’ worth of fuel. At 8 parsecs you need exactly 1. Is there a point, which we can call point X, where you could have exactly 2? That would be useful, because then you could refuel there exactly twice, making full use of your storage capacity without any waste.

Wherever point X is, you’ll jump forward from it twice: once to deposit some fuel at the 8-parsec cache point, and a second time for good. So you’ll jump the distance between X and 8-parsecs 3 times in all. You’d have 2 tanks of fuel at point X, and need 1 left at the 8 parsec cache point, so you can spend one tank— or 15 units— going back and forth. Since 15 units divided by 3 trips is 5, we can place these two cache points 5 parsecs apart. Any farther, and you wouldn’t have enough fuel to reach the alien space station.

Frequently Occurring Word Combinations


ngrams of length 2

collocation frequency
space station 5
alien space 4
ship holds 2
deep space 2
full tank 2

ngrams of length 3

collocation frequency
alien space station 3

Important Words


  1. alien
  2. cache
  3. call
  4. capacity
  5. deposit
  6. distance
  7. divided
  8. fuel
  9. full
  10. good
  11. interesting
  12. jump
  13. left
  14. making
  15. parsec
  16. parsecs
  17. pattern
  18. place
  19. point
  20. points
  21. reach
  22. refuel
  23. space
  24. spend
  25. start
  26. station
  27. storage
  28. tanks
  29. time
  30. times
  31. trips
  32. units
  33. waste
  34. worth