Related by context. Frequent words. (Click for all words.) 70 jarosite 67 lunar craters 65 goethite 63 polar craters 63 olivine 62 meteor impacts 61 exosphere 61 silicates 61 igneous rock 60 heavily cratered 60 meteorite impacts 60 extrasolar 60 icy moons 60 Meridiani 60 lunar soil 60 iron oxides 59 lavas 59 Gusev crater 59 basaltic 59 sulfide minerals 59 magmas 59 Oort cloud 59 spherules 58 ionized gas 58 regolith 58 solar nebula 58 lava tubes 58 hydrothermal activity 58 Valles Marineris 58 clasts 58 clathrates 57 methane hydrate 57 gaseous planets 57 hydrothermal fluids 57 protoplanetary disk 57 interstellar clouds 57 lithosphere 57 aragonite 57 Martian equator 57 planetesimals 57 igneous rocks 57 copper oxides 57 silicate 57 manganese oxide 57 methane CH4 57 sedimentary rock 57 hematite 57 uranium thorium 56 apatite 56 icy crust 56 polar vortex 56 carbonaceous 56 uraninite 56 calcite 56 noctilucent clouds 56 Oort Cloud 56 stellar nurseries 56 Martian dust 56 HiRISE camera 56 photosphere 56 haematite 56 protostars 56 impactors 56 kaolinite 56 landforms 56 moonlets 55 X ray emission 55 pentlandite 55 meteoroids 55 gravitational interactions 55 stockwork veining 55 moon Enceladus 55 siliceous 55 interstellar dust 55 andesitic 55 Scientists theorize 55 erosional 55 monazite 55 Kuiper belt 55 igneous 55 Titan Saturn 55 Martian landscape 55 isotopic composition 55 subglacial 55 basalts 55 osmium 54 ejecta 54 protoplanetary disks 54 elemental composition 54 sulphide deposits 54 gravitational lens 54 Galileo spacecraft 54 spinel 54 solar corona 54 ALH# 54 kimberlitic 54 Archaean 54 cryosphere 54 pyrite pyrrhotite 54 accretion disk 54 magnetic susceptibility