The Universe

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Across
  1. 2. The change in the wavelength or frequency of the waves with respect to the observer who is in motion relative to the source of the wave.
  2. 3. A graph used by scientists which plots luminosity verses temperature of the stars. The y-axis displays increasing luminosity, while the x-axis displays decreasing temperature.
  3. 5. The area in the interior of a star which is above the radioactive zone, where hot gases rise towards the surface and cooler gases sink into the interior.
  4. 6. An instrument used by scientists which spreads light into different wavelengths. It allows scientists to study stars’ characteristics such as temperatures, compositions, distances, and energies.
  5. 9. This is a measure of the distance light travels in 1 year. Since light travels at about 300,000 km/s, that means this is equal to about 10 trillion kilometers!
  6. 11. A huge collection of stars: hundreds of billions of which exist in the universe.
  7. 12. This is the dense, bright part of the star which you can see, where light energy radiates into space: the apparent surface of a star.
  8. 13. an enormous explosion of a star more than 10 times the mass of the Sun, which destroys the star. This occurs when iron forms in a star’s core, causing it to collapse and release a massive amount of energy.
  9. 14. The measure of how bright an object appears from Earth.
  10. 16. A measure of the true brightness of an object (e.g., star), measured using an absolute magnitude scale, dependent upon a star’s temperature, and not its distance from Earth.
  11. 18. Formed from the collapse of the most massive stars and is an object whose gravity is so great that no light can escape.
  12. 19. The wide, outermost layer of a star’s atmosphere. Its temperature is higher than that of the chromosphere or the photosphere. It has an irregular shape and can extend outward for several million kilometers.
  13. 21. A process that occurs when the nuclei of several atoms combine into a larger nucleus, releasing a great amount of energy which powers stars.
Down
  1. 1. This is the orange-red layer of a star, above the photosphere. This is one of the two outer layers of a star.
  2. 4. The average distance between Earth and the Sun, which is about 150 million kilometers.
  3. 7. Matter that emits no light at any wavelength, comprising more than 90% of the universe’s mass.
  4. 8. The eventual phase of an average mass star, like the Sun, and is a hot, dense, slowly cooling sphere of carbon.
  5. 10. – A cloud of gas and dust where stars form, deep within.
  6. 15. A dense core of neutrons that remains after a supernova.
  7. 17. A large ball of gas held together by gravity with a core so hot that nuclear fusion occurs.
  8. 20. Interior area of a star which is a shell of cooler, dense hydrogen above the core.