Related by context. Frequent words. (Click for all words.) 60 plate tectonics 59 hydrological cycle 59 meteorite impacts 59 hydrologic cycle 58 meteor impacts 56 magma ocean 56 planetary atmospheres 55 panspermia 55 lithosphere 55 interstellar clouds 54 atmospheric methane 54 Carbon sequestration 54 extrasolar 54 Neutron stars 54 permafrost thaws 54 sedimentary layers 53 photosynthetic organisms 53 earth crust 53 primitive organisms 53 supervolcano 53 planetesimals 53 Synthetic biology 53 substorm 53 crustal 53 continental drift 53 Burning fossil fuels 53 cryosphere 53 methane CH4 52 tectonics 52 clathrates 52 biogeochemical 52 soliton 52 hydrothermal activity 52 earthquakes volcanic eruptions 52 Earthlike 52 atmospheric chemistry 52 Coal gasification 52 abiotic 52 magmas 52 supercontinent 52 warmings 52 plankton blooms 52 atmospheric phenomena 52 Volcanic eruptions 52 earthquakes volcanoes 51 Arctic permafrost 51 Earth crust 51 landmasses 51 microbial ecology 51 carbonate minerals 51 volcanic eruptions 51 Gondwanaland 51 Liquefaction 51 icy moons 51 ultracold atoms 51 geoid 51 radioactive decay 51 gravitational radiation 51 molten rocks 51 chemical reactivity 51 megathrust 51 Brownian motion 51 multicellular organisms 50 icecaps 50 glacial melt 50 singularities 50 ocean ridges 50 subducted 50 moon Enceladus 50 lunar craters 50 gyres 50 delicate ecosystems 50 coevolution 50 galaxy formation 50 Bose Einstein condensates 50 terrestrial ecosystems 50 fossilization 50 volcanism 50 Snowball Earth 50 photochemical smog 50 ozone layer depletion 50 chemical reactions 50 subglacial 50 Melting glaciers 50 temperature gradients 50 Coral bleaching 50 quantum tunneling 50 saline aquifers 50 melting glacier 50 photochemistry 50 landforms 50 magnetic reconnection 50 geomorphology 49 elementary particle physics 49 explosive eruptions 49 marine sediments 49 El Nino Southern Oscillation 49 continental crust 49 upwellings 49 Solar flares 49 volcanoes