Related by context. Frequent words. (Click for all words.) 69 WMAP 65 distant galaxies 63 redshift 62 quasars 61 cosmologists 61 galaxies 61 galaxy clusters 61 supernovae 61 quasar 60 Saturn rings 60 cosmic rays 59 gamma ray burst 59 gravitational waves 59 gamma ray bursts 59 spectroscopic 57 Milky Way galaxy 57 pulsar 57 neutrinos 57 supernovas 57 gamma rays 56 astronomers 56 cosmological 56 neutron stars 56 Milky Way 56 pulsars 56 exoplanet 56 neutron star 56 infrared wavelengths 55 cosmic ray 55 neutrino 55 brown dwarfs 55 nebula 55 supernova 55 Spitzer Space Telescope 55 comets 55 gamma ray 54 corona 54 comet 54 NASA Chandra 54 rocky planets 54 general relativity 54 magnetosphere 54 Planck 53 ionosphere 53 extrasolar planets 53 exoplanets 53 Einstein theory 53 spectroscopy 53 sunspots 53 Astronomers 53 subatomic particles 53 troposphere 53 photons 52 Chandra X ray 52 magnetic fields 52 astrophysicists 52 laser pulses 52 nebulae 52 quantum theory 52 interstellar space 52 cosmic 52 Enceladus 51 galaxy 51 infrared radiation 51 cosmology 51 Kuiper Belt 51 Astrophysical Journal 51 sunspot 51 Martian surface 50 spectra 50 planets 50 Big Bang 50 cosmos 50 supermassive black hole 50 quantum mechanics 50 photon 50 supermassive black holes 50 polar regions 50 planets orbiting 49 celestial bodies 49 brown dwarf 49 Martian atmosphere 49 moon Titan 49 Solar System 49 atomic particles 49 dynamical 49 solar flares 49 Astrophysical Journal Letters 49 subatomic 48 antimatter 48 atoms 48 volcanism 48 lunar surface 48 diffraction 48 celestial objects 48 moons 48 astrophysics 48 nuclei 48 water vapor 48 THEMIS 48 starlight