Related by context. Frequent words. (Click for all words.) 58 Cepheids 57 Hubble observations 57 galaxy formation 57 redshifts 55 XMM Newton 54 Galaxy Evolution 54 elliptical galaxies 54 Voyager spacecraft 54 supernova explosion 54 planetary nebulae 54 morphologies 53 innermost planet 53 dwarf galaxy 53 radial velocity 53 magnetars 53 distant galaxy 53 distant galaxies 53 Saturn moons 53 Type Ia supernovae 52 terrestrial planets 52 Saturn rings 52 galaxies 52 supernova remnants 52 Kuiper belt 52 quasars 52 Crab Nebula 52 globular cluster 52 moonlets 52 magnetar 52 microlensing 51 magnetic reconnection 51 globular clusters 51 solar corona 51 cosmic microwave background 51 baryons 51 planets 51 Orion Nebula 51 Andromeda galaxy 51 high temperature superconductivity 51 GRB # 51 supernovae 50 anisotropy 50 solar nebula 50 redshift 50 X ray emission 50 aurorae 50 active galactic nuclei 50 Higgs particle 50 rocky planets 50 spectra 50 optical wavelengths 50 GRBs 50 galaxy cluster 50 spectroscopic 50 brown dwarfs 50 gravitational wave 49 astronomical objects 49 galaxy clusters 49 WMAP 49 elemental composition 49 dwarf galaxies 49 planetary nebula 49 Earth magnetosphere 49 celestial bodies 49 comet tail 49 Milky Way galaxy 49 lava tubes 49 planetesimals 49 frequency comb 49 Mimas 49 Milky Way Galaxy 49 Valles Marineris 49 habitable planets 49 spatial dimensions 49 Eta Carinae 49 feathered dinosaurs 49 observable universe 49 Iapetus 48 supernova explosions 48 Oort Cloud 48 WASP #b 48 HD #b [002] 48 spacetime 48 Andromeda Galaxy 48 silicon atoms 48 Large Magellanic Cloud 48 Hawking radiation 48 planets orbiting 48 oxygen isotopes 48 heliosphere 48 supernova remnant 48 quasar 48 interstellar medium 48 Cancri 48 auroral 48 morphological 48 z = 48 photometry 48 spiral galaxies 48 Gliese #g 48 nebula