Related by context. Frequent words. (Click for all words.) 61 general relativity 61 quantum theory 59 cosmologists 59 Einstein theory 52 cosmic microwave background 51 neutrinos 51 gravitational 51 deuterium 50 neutron star 50 radioactive decay 50 hydrogen atoms 50 atoms 50 cosmic ray 50 positrons 50 gravitational waves 50 quantum mechanics 50 entropy 50 brown dwarfs 50 redshift 49 galaxy clusters 49 atomic nuclei 49 Big Bang theory 49 astrophysical 49 cosmological 49 quasar 49 cosmic rays 49 subatomic 49 photon 48 neutrino 48 rocky planets 48 electromagnetism 48 Higgs boson 48 quasars 48 electron spin 48 nuclei 48 Uranus 48 cosmology 48 heliosphere 47 atomic particles 47 subatomic particles 47 photons 47 globular clusters 47 hydrogen atom 47 quantum mechanical 47 Einstein 47 magnetic fields 47 superconductivity 47 brown dwarf 47 universe 47 protons 47 quarks 47 neutron stars 47 electron 46 dwarf galaxies 46 neutrons 46 particle 46 galaxies 46 albedo 46 antimatter 46 superposition 46 proton 46 scalar 46 high temperature superconductors 46 quantum physics 46 supernovae 46 relativistic 45 planet orbiting 45 planets 45 multiverse 45 qubit 45 particle physics 45 astrophysicists 45 WMAP 44 particle accelerators 44 liquid helium 44 supernovas 44 electrons 44 pulsars 44 theorems 44 angular momentum 44 quark 44 gravitation 44 Feynman 44 spiral galaxies 44 supermassive black holes 44 interstellar medium 44 dynamical 44 magnetization 44 distant galaxies 43 relativity 43 cosmic 43 supermassive black hole 43 nanocrystals 43 exoplanets 43 superconductor 43 pulsar 43 exoplanet 43 spectrograph 43 gamma ray bursts 43 singularity 43 XMM Newton