Related by context. Frequent words. (Click for all words.) 56 classical antiquity 50 Halley comet 50 Voyager spacecraft 50 Babylonia 50 volcanically active 50 Greek philosophers 49 astronomical observations 49 Ptolemaic 49 ancients 48 #BC [002] 48 NASA Cassini 48 hydrothermal vent 48 Phaethon 48 Galilean 47 Justinian 47 Sedna 47 Edwin Hubble 47 astronomers 47 Orion Nebula 47 Meridiani 47 extrasolar planets 47 Kuiper belt 46 Minoan 46 landforms 46 Pythagoras 46 occultation 46 ESO Very Large Telescope 46 Herodotus 46 WM Keck Observatory 46 innermost planet 46 Hubble observations 46 planetary nebulae 46 Chicxulub 46 comet 46 Ionian 46 Gautama Buddha 46 Etruscans 46 lunar poles 45 optical telescope 45 lunar 45 distant galaxy 45 Haumea 45 ancient Greeks 45 Copernicus 45 Saturn moon 45 volcanism 45 Eta Carinae 45 celestial bodies 45 astronomer 45 Pentateuch 45 HD #b [002] 44 Ptolemy 44 Lutetia 44 Galaxy Evolution 44 solstices 44 Comet McNaught 44 COROT 44 XMM Newton 44 Saturn moons 44 microfossils 44 explorers 44 cosmology 44 Babylonians 44 observatories 44 GRB # 44 Ferdinand Magellan 44 scarps 44 orbiting Saturn 44 Rig Veda 44 MARSIS 44 Archimedes 44 Samos 44 ancient Greek 44 meteoroids 44 Einstein theory 44 caldera 44 rock outcrops 44 geologic 44 Gnostics 44 Space Telescope 43 Jupiter moons 43 Byzantine era 43 GOCE 43 Roman mythology 43 megalithic 43 Josephus 43 Hebrew Scriptures 43 supercontinent 43 GRBs 43 cosmological 43 millenniums 43 Keck Observatory 43 Vespucci 43 glaciated 43 Herschel 43 ancient 43 Saturn rings 43 prehistory 43 antiquity 43 magnetar 43 THEMIS