LC ClassificationQB63.B49

16th century(183) 17th century(310) academic(111) aliens(251) asteroids(68) astrobiology(257) astrology(370) astrophysics(619) Biographies(157) biography(3,275) biology(305) black holes(111) children(373) children's(505) cosmology(1,647) cosmos(165) earth(269) education(169) educational(70) Europe(118) evolution(165) experiments(75) exploration(90) extraterrestrial(53) extraterrestrials(165) galaxies(256) galaxy(84) Galileo(914) general science(63) geography(148) gravity(43) guide(328) guidebook(104) history(3,519) history of ideas(62) history of science(1,789) how-to(97) informational(146) inventors(61) Isaac Newton(32) Italy(382) Jupiter(65) juvenile(181) juvenile non-fiction(106) kids(129) maps(132) Mars(109) math(487) meteors(47) moon(484) nasa(66) natural science(282) nature(580) observation(145) outer space(346) philosophy of science(115) photographs(96) photography(317) physics/astronomy(44) picture book(575) planet(66) planets(1,531) Pluto(45) popular science(486) quasars(29) reference(2,013) reference guide(28) religion(288) Renaissance(312) rockets(48) science(16,608) Science & Technology(124) science biography(43) science nonfiction(63) scientific revolution(56) scientists(340) solar system(1,157) space exploration(270) space flight(51) stars(2,102) time(94) universe(807)