Across
- 4. attracts the planets to the Sun (1)
- 8. a device designed to collect as much light as possible from some distant source and deliver it to a detector for detailed study (3)
- 10. a measure of the speed with which its constituent particles move (2)
- 11. the mass in galaxies and clusters whose existence we infer from rotation curves and other techniques, but that has not been confirmed by observations at any electromagnetic wavelength (14)
- 14. the tenuous outer atmosphere of the Sun, which lies just above the chromosphere and, at great distances, turns into the solar wind (9)
- 17. the distance from a planet at which the tidal force (due to the planet) between adjacent objects exceeds their mutual attraction (8)
- 19. layer of permanently frozen water ice believed to lie just under the surface of Mars (6)
- 20. a giant star whose surface temperature is relatively low so that it glows red (10)
- 22. a type of galaxy that does not fit into any of the other major categories in the Hubble classification scheme (15)
- 24. totality of space, time, matter, and energy (0)
- 25. dwarf star with sufficiently high surface temperature that it glows white (10)
- 27. object that emits radiation in the form of rapid pulses with a characteristic pulse period and duration (13)
- 28. the extent to which the atmosphere absorbs radiation (2)
- 29. grouping of anywhere from a dozen to a million stars that formed at the same time from the same cloud of interstellar gas (11)
- 31. icy and rocky fragments that normally orbit far from the Sun (4)
- 32. the collection of the seven major phases of the history of the universe, namely particulate, galactic, stellar, planetary, chemical, biological, and cultural evolution (18)
- 34. regions on the surface of Mercury that do not show extensive cratering but are relatively smooth (6)
- 37. the tendency for a gaseous sphere, such as a Jovian planet or the Sun, to rotate at a different rate at the equator than at the poles (7)
- 38. the study of the universe (0)
Down
- 1. grouping of several clusters of galaxies into a larger, but not necessarily gravitationally bound unit (16)
- 2. remnants of a meteor (4)
- 3. this equation is an expression that gives an estimate of the probability that intelligence exists elsewhere in the Galaxy, based on a number of supposedly necessary conditions for intelligent life to develop (18)
- 5. rising and falling motion of terrestrial bodies of water, exhibiting daily, monthly, and yearly cycles (5)
- 6. large, relatively empty region of the universe around which superclusters and “walls” of galaxies are organized (16)
- 7. the average distance from the Earth to the Sun (1)
- 9. a glowing ball of gas held together by its own gravity and powered by nuclear fusion in its core (9)
- 12. a region of space where the pull of gravity is so great that nothing—not even light—can escape (13)
- 13. the middle of the Milky Way, or any other galaxy. The point about which the disk of a spiral galaxy rotates (14)
- 15. a large, high-pressure, long-lived storm system visible in the atmosphere of Jupiter (7)
- 16. the scattered glowing remains from a supernova that occurred in the past (12)
- 18. these telescopes are designed to collect as much light as possible from some distant source and deliver it to a detector for detailed study (3)
- 21. the study of the structure and evolution of the entire universe (17)
- 23. the release of energy by rare, heavy elements when their nuclei decay into lighter nuclei (5)
- 26. the matter between stars, composed of two components, gas and dust, intermixed throughout all of space (11)
- 30. the result of an explosion on the surface of a white-dwarf star (12)
- 33. event that cosmologists consider the beginning of the universe, in which all matter and radiation in the entire universe came into being (17)
- 35. dwarf planets orbiting beyond Neptune (8)
- 36. starlike radio source with an observed redshift that indicates an extremely large distance from Earth. The brightest nucleus of a distant active galaxy (15)