Astronomy 100 Unit#3 Exam Review Crossword

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Across
  1. 5. A cloud of gas/dust or a dense concentration of interstellar material, like along the ecliptic of the Milky Way Galaxy, that blocks light from objects behind it.
  2. 6. In the evolution of stars, this is a clump of gas that will become a new star and is just before fusion begins.
  3. 8. An expanding cloud of debris from a supernova explosion.
  4. 12. A cloud of gas and dust that reflects light off nearby stars.
  5. 13. These are also pulsars and are a ball of neutrons created by the collapse of the iron core in a massive star supernova.
  6. 14. A cloud of high temperature gas that absorbs UV light from an embedded or nearby star.
  7. 15. Emission and reflection nebulas are types of this nebula all of which are extended and contain no well defined boundaries.
  8. 19. A 2 star system in which 2 stars orbit each other.
  9. 20. Hotter objects emit photons with a higher average energy and a shorter average wavelength.
  10. 21. Radiation emitted by a heated object that depends only on temperature (also called Thermal Radiation).
  11. 24. The distance from a black hole within which the escape velocity is the speed of light and can be described as the surface surrounding the black hole.
  12. 27. 2 stars that orbit one another that can be detected with a telescope (your eye).
  13. 32. An ejection of unused stellar material or the outer layers (stellar atmosphere) of a star.
  14. 34. A device that measures the spectra of light.
  15. 39. The formation of 8 elements (H, He, C, O, Ne, Mg, Si, Fe) in a star by nuclear fusion.
  16. 42. Spectrum produced by a thin or low density cloud of gas that emits light only at specific wavelengths depending on the temperature and composition of the cloud.
  17. 45. Very small mass stars with very long lives that are cool, red, and have nuclear fusion with convection in their cores.
  18. 46. How bright a star appears in the night sky.
  19. 47. Infinitely small and dense point at the center of a black hole.
  20. 48. 2 stars that orbit each other that are recognized by the variation in luminosity because they orbit in the plane of our line of sight.
  21. 49. The true brightness of a star based on the brightness of a star at a distance of 10pc from Earth.
  22. 50. An object too small to become a star because electron degeneracy pressure halts fusion.
  23. 51. The particle of light that is a mass less bundle of electromagnetic energy.
  24. 52. The science of splitting light into its various wavelengths to study the properties of light that depend on wavelength.
Down
  1. 1. Betelgeuese is one of these and they are very luminous because they are large in size.
  2. 2. The process of an object being stretched by the strong gravitational forces near a black hole.
  3. 3. The process by which energy is generated in nuclear power plants.
  4. 4. Plot of luminosity versus temperature to highlight patterns and evolution in stars.
  5. 7. 2 stars that orbit each other that are detected only by the changing of the wavelength of light from them from observations of Doppler shifts.
  6. 9. The event that marks the sudden onset of helium fusion in the previously inert helium core of a low mass star.
  7. 10. A type of star that varies in luminosity that can be used to determine distances because it follows a period-luminosity relation.
  8. 11. This is the condition reached the moment fusion begins in the evolution of a star when nuclear fusion balances the force of gravity.
  9. 16. The technique astronomers use to determine the chemical composition of stars by using chemical fingerprints to determine the elements.
  10. 17. Spectrum produced by an incandescent solid, liquid, or gas under high pressure containing all wavelengths.
  11. 18. Another term for brightness described as the total amount of energy radiated by a star every second.
  12. 22. Neutron stars are composed of these.
  13. 23. Pressure that arises when electrons or neutrons are packed so tightly Quantum Mechanics comes into play.
  14. 25. A technique to determine distances to stars that are closer than 100 parsec from the slight shifting in the apparent position of a star caused by Earth’s motion around the Sun.
  15. 26. When a massive star begins to fuse iron and then explodes.
  16. 28. When mass from a Red Giant is pulled into a White Dwarf and the White Dwarf then explodes after its mass limit is reached.
  17. 29. The effect that shifts the wavelengths of spectral features in objects that are moving toward or way from an observer.
  18. 30. The process by which all main sequence stars generate huge amounts of energy, aka ‘Hydrogen burning.’
  19. 31. A star whose luminosity changes with time.
  20. 33. Gas and dust concentrations in space.
  21. 35. A star that changes luminosity because it gets bigger and smaller in size.
  22. 36. Classifies stars based on decreasing temperature.
  23. 37. White Dwarfs are composed of these and their pressure supports against gravity.
  24. 38. This is a neutron star you can listen to, like ‘The Crab,’ because we observe rapid pulses of radio waves as it rotates.
  25. 40. The stellar corpse for stars that are low to intermediate in mass (1.4 to 4 times the mass of the Sun).
  26. 41. The Doppler effect where the wavelength of the absorption bands/wavelengths increases because the light source is moving away from the observer.
  27. 43. This has an escape velocity equal to the speed of light so light cannot escape it.
  28. 44. The splitting of light into its various wavelengths.