Stars and Galaxies and Cosmology Review

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Across
  1. 2. The small spiral arm of the Milky Way where Earth and our Sun are located.
  2. 3. A mysterious force that is causing the expansion rate of the universe to accelerate.
  3. 7. An extremely large star that can fuse elements up to iron
  4. 8. An early stage in star formation before nuclear fusion begins
  5. 10. The nuclear process that combines lighter atoms into heavier ones inside a star
  6. 11. The distance light travels in one Earth year, equal to roughly 9.46 trillion kilometers.
  7. 16. The hot, dense core left behind after a low-mass star sheds its outer layers
  8. 18. A smooth, egg-shaped galaxy containing mostly old stars and very little gas or dust.
  9. 19. The law stating that the speed at which a galaxy recedes is directly proportional to its distance from us.
  10. 23. The classification system using the letters O B A F G K M
  11. 25. A giant cloud of gas and dust in space where new stars are born
  12. 26. An expanded, cooler stage when a sun-like star runs out of core hydrogen
  13. 27. The change in wave frequency caused by the relative motion between a wave source and an observer.
  14. 29. An object with gravity so intense that not even light can escape it
  15. 30. The scientific study of the origin, structure, evolution, and ultimate fate of the universe.
  16. 32. The stretching of light toward longer wavelengths as a cosmic object moves away from Earth.
  17. 33. The largest spiral galaxy in our Local Group, currently on a collision course with the Milky Way.
  18. 34. The violent explosion of a high-mass star at the end of its life
  19. 35. A category of galaxy with no symmetrical or defined shape, often rich in gas and dust.
  20. 36. An extremely dense stellar remnant left over from a supernova
Down
  1. 1. The barred spiral galaxy that contains Earth and our solar system.
  2. 4. Invisible matter that emits no light but exerts gravitational force, holding galaxies together.
  3. 5. The total amount of light output a star emits per second
  4. 6. The star property on the X axis of an HR diagram running high to low
  5. 9. The rainbow pattern of colors or dark emission/absorption lines used to analyze stellar composition and movement.
  6. 12. An expanding shell of gas blown off by an aging red giant
  7. 13. The dense, spherical center of a spiral galaxy packed tightly with older Population II stars.
  8. 14. The balance between the inward pull of gravity and outward pressure
  9. 15. An extremely bright and distant active galactic nucleus powered by a supermassive black hole.
  10. 17. The sparse, spherical outer region of a spiral galaxy containing old stars and globular clusters.
  11. 20. The shortening of light waves toward higher frequencies as an object moves toward the observer.
  12. 21. The element whose fusion in a massive star core triggers a supernova
  13. 22. The brightest star in our night sky with a white dwarf companion
  14. 24. A famous red supergiant star located in the constellation Orion
  15. 28. The small cluster of over 50 galaxies that includes the Milky Way and Andromeda.
  16. 31. The stable phase of a star's life where it fuses hydrogen into helium