Black Holes

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Across
  1. 2. the gradual accumulation of small objects to form a larger object due to their mutual gravitational attraction.
  2. 5. the speed at which light travels
  3. 8. the distance light travels in one year, approximately 9.46 trillion meters (5.88 trillion miles).
  4. 11. a flattened disk of matter orbiting around an object.
  5. 13. the outer boundary of a black hole, at which the escape velocity exceeds the speed of light.
  6. 14. the radius of an object with a given mass at which the escape velocity equals the speed of light.
  7. 15. the attractive force between any two bodies that is the result of their masses.
  8. 16. a structured grouping of billions of stars, gas, and dust, bound together by their collective gravity and orbiting a common center.
  9. 19. form at the cores of galaxies, where they grow larger and larger, feeding on the gas and dust at the center.
  10. 20. an extremely massive concentration of matter so dense that even light cannot escape its gravitational field.
Down
  1. 1. the velocity required for one object to be launched from the surface of a body in order for it to escape the gravitational attraction of that body.
  2. 3. infer that tubes, or tunnels, might exist within the strange world of black holes
  3. 4. the most powerful form of electromagnetic radiation, with the shortest wavelengths.
  4. 6. the slowing of the flow of time, which may be observed for objects that approach the event horizon of a black hole.
  5. 7. an explosion caused by the collapse of the core of a massive star.
  6. 9. the center of a black hole, an infinitely dense remnant of a massive star’s core collapse.
  7. 10. forms when a star at least eight times the mass of our Sun explodes at the end if its life in a blaze of glory called a supernova.
  8. 12. a burst of gamma rays from space, possibly triggered by the birth of black holes.
  9. 17. first name of wormholes
  10. 18. theoretical “tubes” in space-time.