Related by context. Frequent words. (Click for all words.) 66 landmasses 61 lithosphere 56 continental crust 55 plate tectonics 55 ocean ridges 55 single celled organisms 54 Kuiper belt 54 continental drift 53 oceanic crust 53 dwarf galaxy 53 Earth crust 53 Saturn rings 53 supernova explosion 52 Gondwana 52 multicellular 52 tetrapods 52 spacetime 52 megafauna 52 globular clusters 52 zircons 52 calcite 52 lavas 52 subduction zones 52 Younger Dryas 51 landforms 51 spiral galaxies 51 earth crust 51 crustal 51 trilobites 51 multicellular organisms 51 epochs 51 galaxy clusters 51 olivine 50 nuclei 50 interglacial period 50 magnetar 50 dwarf galaxies 50 supernova explosions 50 vortices 50 galaxy formation 50 earths 50 filaments 50 neutron stars 50 rocky planets 50 Precambrian 50 sedimentary rock 50 graphene sheets 50 volcanism 50 Computer simulations 50 accretion disk 50 planets 49 magma chamber 49 Archaea 49 Ross Ice Shelf 49 terrestrial planets 49 Cretaceous Period 49 organic molecules 49 galaxies 49 diatoms 49 elliptical galaxies 49 polar caps 49 symmetries 49 excitons 49 torus 49 volcanic islands 49 ejecta 49 planet orbits 49 microfossils 49 Andromeda galaxy 49 Homo sapiens 49 interglacial 49 Weddell Sea 48 quark gluon plasma 48 hot Jupiters 48 oxygen isotopes 48 quasars 48 superfluid 48 concentric rings 48 galaxy cluster 48 Late Cretaceous 48 Voyager spacecraft 48 atomic nuclei 48 atoms 48 glaciation 48 lineages 48 dynamical 48 subduction 48 magnetosphere 48 Wilkins Ice Shelf 48 anatomically modern 48 Bose Einstein condensate 48 sediments 48 antiprotons 48 morphologies 47 photonic crystal 47 Tibetan Plateau 47 neutron star 47 Meteorites 47 comets 47 GRBs 47 Theorists