Puzzle

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Across
  1. 2. Chemical element with symbol "Pt" (6)
  2. 3. Japanese martial art (4)
  3. 5. Study of celestial bodies (8)
  4. 9. French philosopher and mathematician who said, "I think, therefore I am" (5)
  5. 12. Nobel Prize-winning physicist who developed the theory of relativity (6)
  6. 13. Element with the atomic number 79 (4)
  7. 14. Fictional detective created by Arthur Conan Doyle (6)
  8. 15. Shakespearean tragedy (5)
Down
  1. 1. Largest planet in our solar system (6)
  2. 2. Greek philosopher known for his theory of forms (7)
  3. 4. Capital city of Norway (6)
  4. 6. French impressionist painter (6)
  5. 7. Japanese currency (3)
  6. 8. Longest river in Asia (4)
  7. 10. Unit of electric current (4)
  8. 11. Ancient Egyptian symbol of protection (5)