Related by context. Frequent words. (Click for all words.) 48 Apophis 47 Tunguska 47 Saturn rings 46 asteroid 46 atmospheric chemistry 46 impactor 45 comet nucleus 45 ejecta 45 computer simulations 45 general relativity 44 meteor 44 Landsea 43 Einstein theory 43 HiRISE 43 comet 42 cosmic ray 42 supernova explosion 42 cometary 41 gravitational lensing 41 micrometeorites 41 meteorite 40 plate tectonics 40 GRBs 40 outer planets 40 cosmologists 40 cosmic microwave background 40 orbital debris 40 galaxy clusters 40 crater 40 X ray diffraction 40 neutron star 40 seismic waves 39 Itokawa 39 laser pulses 39 greenhouse warming 39 astrophysicists 39 spacetime 39 NASA Chandra 39 astrophysical 39 craters 39 volcanic eruptions 39 comet dust 38 quantum theory 38 neutrino 38 optical telescopes 38 radiocarbon dating 38 Nature Geoscience 38 Tempel 1 38 dwarf galaxies 38 NASA Cassini spacecraft 38 olivine 38 sediment cores 38 asteroids 38 fragments 38 lunar surface 37 atomic nuclei 37 WMAP 37 meteorites 37 LCROSS 37 Iapetus 37 gravitational waves 37 Martian atmosphere 37 heliosphere 37 IceCube 37 magnetosphere 37 Victoria Crater 37 terrestrial planets 37 atomic particles 37 quantum mechanical 37 journal Nature Geoscience 37 Martian surface 37 elliptical galaxies 37 comets 37 plumes 37 astronomers 37 supernovae 37 subatomic particles 37 magnetic fields 36 neutron stars 36 Saturn moons 36 physicists 36 ringed planet 36 supernovas 36 meteors 36 sonic boom 36 plume 36 macroscopic 36 physics 36 distant galaxy 36 Review Letters 36 vortices 36 fractals 36 cosmic rays 35 gamma ray burst 35 journal Geophysical Research 35 spectroscopic 35 regolith 35 Phobos 35 neutrinos 35 comet Tempel 1 35 buckyballs