Earth Science - Book 903 - Words to Know

3. element that is rare on Earth but found in large quantities in asteroids and meteorites
7. small, rocky body
8. star found to have a planet orbiting it
10. average distance of the sun from Earth
12. heavy nucleus split into two or more lighter segments
13. largest asteroid; discovered in 1801
15. mixture of fine dust and rocky debris produced by meteor impacts on the moon's surface
20. having orbital periods less than one-fourth of Jupiter's
23. normal, sun-like star
25. dimmest star in Alpha Centauri system
26. second-largest asteroid
30. group of inner-belt asteroids
32. third brightest star in the night sky single, heavier nucleus
33. multi-ring crater on the moon
37. large impression on Mercury's surface
38. star surrounded by gas and dust
39. planets orbiting stars other than our sun

1. extremely dense, rapidly spinning neutron star
2. relatively empty regions in the main belt; lighter segments
4. cool, dark areas on the sun's surface
5. star found to have a planet orbiting it
6. site containing remnants of iridium
9. gas planet formed far from its star that migrated inward
11. energy released by fission or fusion of nuclei, in the form of heat, light, or other radiation
14. separate cells of hot gas
16. having orbital period greater than one-half that of Jupiter
17. the brightest star in the northern constellation Lyra and fourth brightest in the night sky
18. having orbital period between one-fourth and one-half of Jupiter's
19. rotation period of the sun
21. difference in planet's rotation at equator compared to poles
22. brightest star in Alpha Centauri system
24. third asteroid found; discovered in 1804
27. star closest to the sun
28. brightest asteroid
29. asteroid that crashed into the earth 65 million years ago
31. largest impact basin in the solar system; found on the moon
34. relatively smooth basins on the moon
35. combining of two light nuclei to form a single, heavier nucleus
36. asteroid that crashed into Atlantic Ocean 2 million years ago