Related by context. Frequent words. (Click for all words.) 71 cosmic microwave background 63 WMAP 58 XMM Newton 58 radioactive decay 58 spectroscopic 58 magnetar 57 supernova explosion 57 supernova remnant 57 quasars 57 redshift 57 Crab Nebula 57 Gamma ray bursts 56 supernova explosions 56 galaxy formation 56 cosmic ray 56 supernovae 56 GRBs 55 X ray emission 55 cosmic rays 55 interferometry 55 cosmologists 55 gravitational lensing 55 COROT 55 astronomical objects 55 isotopic 55 distant galaxies 55 galaxy cluster 55 supernova 54 astronomers 54 gamma ray burst 54 infrared wavelengths 54 muon 54 NASA Chandra 54 gamma rays 54 globular clusters 53 neutrino 53 Orion Nebula 53 brown dwarfs 53 cosmological 53 antiprotons 53 astrophysical 53 gamma ray bursts 53 Planck 53 cosmic 53 Eta Carinae 53 globular cluster 53 quasar 53 pulsars 52 Big Bang 52 microlensing 52 alpha particles 52 gravitational wave 52 WIMPs 52 Gamma Ray 52 comet nucleus 52 galaxy clusters 52 gamma ray 52 extrasolar planet 52 supernovas 52 occultation 52 MARSIS 52 GeV 52 laser pulses 51 quark gluon plasma 51 pulsar 51 neutron stars 51 general relativity 51 particle beam 51 X ray Observatory 51 interstellar dust 51 distant galaxy 51 sunspot cycle 51 Spectrometer 51 photonic crystal 51 neutrinos 51 subatomic 51 Voyager spacecraft 51 celestial objects 51 astrophysicists 50 auroral 50 galaxies 50 ejecta 50 Gravity Probe B 50 atomic nuclei 50 Spitzer Space Telescope 50 HD #b [002] 50 Cassini Huygens 50 spectrometry 50 exoplanet 50 Andromeda Galaxy 50 quantum gravity 50 Raman spectroscopy 50 interstellar medium 50 Chandra X ray 50 nebulae 50 krypton 50 diffraction 50 outer planets 50 subatomic particle 50 spectroscopy 50 accretion disk