Puzzle 19: Relativity and Space-Time

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Across
  1. 2. – Region of space with gravity so strong nothing can escape
  2. 5. – Term for bending of space-time
  3. 9. – Thought experiment illustrating time dilation
  4. 10. – Einstein’s theory linking space and time
  5. 12. – The boundless three-dimensional extent in which objects exist
Down
  1. 1. – Hypothetical shortcut through space-time
  2. 3. – Travels at 299,792 km/s in a vacuum
  3. 4. – Force that attracts objects toward each other
  4. 6. – Distance traveled per unit of time
  5. 7. – Amount of matter in an object
  6. 8. – Fourth dimension in physics
  7. 11. – Concept in sci-fi of frozen or delayed time