Related by context. Frequent words. (Click for all words.) 74 cosmic microwave background 63 solar corona 63 solar nebula 61 galaxy formation 61 outer planets 61 planetary nebulae 61 WMAP 61 Oort Cloud 60 astrophysical 59 Hubble observations 59 X ray emission 59 Hawking radiation 59 Kuiper belt 59 XMM Newton 59 extrasolar planet 59 Galaxy Evolution 58 interplanetary spacecraft 58 COROT 58 MARSIS 58 Saturn rings 58 cosmic ray 58 Crab Nebula 58 supernova remnant 58 magnetar 58 distant galaxies 58 comet nucleus 57 observable universe 57 Higgs particle 57 Voyager spacecraft 57 auroral 57 galaxy cluster 57 interstellar dust 57 supernova remnants 56 Gamma ray bursts 56 Mini SAR 56 NASA Cassini spacecraft 56 radial velocity 56 spacetime 56 Type Ia supernovae 56 ringed planet 55 cosmologists 55 Milky Way Galaxy 55 gravitational waves 55 HD #b [002] 55 muon 55 Halley comet 55 cosmological 55 accretion disk 55 cosmic rays 55 gamma ray burst 55 supernova explosions 55 gravitational lensing 55 ejecta 55 magnetic reconnection 55 ionospheric 55 planetary nebula 55 astronomical objects 55 Brownian motion 55 innermost planet 55 visible wavelengths 55 supernova explosion 55 spectroscopic 55 polar caps 55 redshift 55 WFC3 54 cosmos 54 Cabeus crater 54 Saturn moons 54 radioactive decay 54 Planck 54 Cassini Huygens 54 magnetosphere 54 NASA Cassini 54 Gamma rays 54 redshifts 54 quark gluon plasma 54 Astrophysicists 54 galaxy clusters 54 Earth magnetosphere 54 pulsar 54 Gliese #g 54 comet Wild 54 cosmic 54 gravitational wave 54 ionosphere 54 Orion Nebula 54 distant galaxy 54 photometer 53 interferometry 53 neutrino 53 astronomical observations 53 NASA Chandra 53 infrared wavelengths 53 colliding galaxies 53 Eta Carinae 53 active galactic nuclei 53 magnetic fields 53 Solar System 53 Saturn moon 53 Cancri 53 particle detectors