Stars and the Universe

4. a galaxy with no defined, recognizable shape; contains mostly young stars
6. a dark area of the photosphere of the sun that is cooler than the surrounding areas and that has a strong magnetic field
8. how bright as star appears as seen from Earth
10. A ball of hot gas, primarily hydrogen and helium, that undergoes nuclear fusion
15. a galaxy shaped like a round or flattened ball, generally containing only old stars
16. the average distance between the Earth and the Sun; used as a unit of measurement inside the Solar System
17. a sudden eruption of intense high-energy radiation from the sun's surface
18. a collection of stars, dust, and gas bound together by gravity
19. the distance light travels in one year; used as a unit of measurement of the distance between stars
23. the layer of the sun's interior where energy is transferred outward from the core
24. space and all the matter and energy in it
26. a diagonal area on an H-R diagram that includes more than 90 percent of all stars

1. the hottest/highest-temperature stars
2. a large body in space that orbits a star and does not produce light of its own
3. the outer layer of the sun's atmosphere.
5. to spin on an axis
7. a galaxy in which the stars and gas clouds are concentrated mainly in one or more spiral arms
9. a loop of gas that protrudes from the sun's surface, linking sunspot regions
10. the continuous flow of charged particles from the sun
11. a star and all of the planets and other objects that revolve around it
12. layer of the sun where hot gas moves up toward the surface and cooler gas moves deeper into the interior
13. how bright a star actually is as mesaured from a fixed distance
14. to move in a circular path around another object
20. the visible surface of the sun
21. a graph organizing stars by their temperature and brightness
22. the central part of the sun where nuclear fusion occurs
25. the coolest/lowest-temperature stars