Universe stuff, or something like that

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Across
  1. 3. The amount of matter in a physical body, usually measured in Kg or kilograms
  2. 5. A large astronomical body that is commonly recognized to orbit stars.
  3. 6. A triple star system that consists of 3 stars: Rigil Kentaurus, Toliman, and Proxima Centauri
  4. 8. A space cloud. Most stars are born here.
  5. 10. Twice long I can stay focused, or (3^2)10
  6. 11. Also referred to as the North Star
  7. 12. The galaxy that contains the sun and all the planets that orbits it.
  8. 16. A ring of icy objects around the sun at just the distance of neptune
  9. 17. Hot giant mass of helium, lithium, and hydrogen
  10. 18. A area of space where gravity is so strong even light gets absorbed by it.
  11. 19. The distance light travels in a single year.
  12. 20. A force that attracts items based on the mass of a object.
  13. 22. The closest large galaxy to the milky way
  14. 23. A space probe launched to study the space outside the sun's heliosphere.
Down
  1. 1. A objects resistance to motion
  2. 2. A object that orbits a planet.
  3. 4. The largest manmade satellite.It can contain humans.
  4. 7. A collection of stars viewed as animals, people, or items
  5. 9. The first element of the periodic table
  6. 13. The circular movement around one astronomical body from another.
  7. 14. A telescope used to view deep into space
  8. 15. The planet of origin of human life.
  9. 21. A system that contains stars, dust, gas, and astronomical bodies.