Related by context. Frequent words. (Click for all words.) 66 active galactic nuclei 63 globular cluster 63 elliptical galaxies 62 planetary nebulae 62 globular clusters 60 galaxies 60 accretion disk 59 supermassive black holes 59 spiral galaxies 58 torus 58 planetary nebula 58 galaxy clusters 58 dwarf galaxy 58 galaxy cluster 58 colliding galaxies 57 Kuiper belt 57 neutron stars 57 galaxy formation 57 brown dwarfs 57 ionized gas 57 dwarf galaxies 56 neutron star 55 quasars 55 X ray Observatory 55 magnetar 55 distant galaxies 55 rocky planets 55 supermassive black hole 55 distant galaxy 54 Type Ia supernovae 54 nebulae 54 supernova remnants 54 Milky Way Galaxy 54 clusters 54 quasar 54 Hawking radiation 54 Andromeda galaxy 54 X ray emission 54 nebula 54 brown dwarf 53 supernova explosion 53 Milky Way 53 Milky Way galaxy 53 supernova remnant 53 dense 53 supernova explosions 52 tubules 52 spiral galaxy 52 spacetime 52 singularities 52 solar nebula 52 nuclei 52 accreting 52 Crab Nebula 52 HD #b [002] 52 hot Jupiters 52 Gamma ray bursts 51 GRBs 51 Orion Nebula 51 filaments 51 continental crust 51 planet orbits 51 galaxy 51 terrestrial planets 51 supernovae 51 sepals 50 quark gluon plasma 50 Bose Einstein condensate 50 subatomic particle 50 ejecta 50 Cosmic rays 50 Earth magnetosphere 50 gravitationally 50 globular 50 starbursts 50 olivine 50 super Earths 50 observable universe 50 vortices 50 haloes 50 supernovas 49 nanometer sized 49 Cancri 49 spatial dimensions 49 star Gliese 49 almond shaped 49 supercluster 49 lava tubes 49 superfluid 49 optical telescopes 49 clumpy 49 quantum gravity 49 siliceous 49 gravitational lensing 49 hydrothermal vent 49 constellation Leo 49 calcareous 49 ocean ridges 48 liquid droplets 48 outer crust 48 GRB #