Related by context. Frequent words. (Click for all words.) 75 ultraviolet light 73 UV 69 ultra violet 69 UV light 64 ultra violet light 62 infrared 61 ultraviolet radiation 60 UVB 59 UV radiation 58 wavelengths 57 Ultraviolet 56 UVA rays 56 ultraviolet rays 56 infrared wavelengths 55 infrared radiation 55 UV rays 53 infra red 53 spectroscopic 52 rays 51 UVB rays 50 brightness 50 gamma rays 50 luminescence 50 sunlight 50 fluorescence 50 ionizing 50 XMM Newton 50 fluorescent 50 reflectivity 49 sun rays 49 infrared IR 49 photometric 49 reflectance 49 Raman spectroscopy 49 lasers 49 cosmic ray 48 fluorescent dyes 48 interferometry 48 Infrared 48 hydroxyl 48 ambient light 48 reflective coating 47 harmful UV rays 47 multispectral 47 spectroscopy 47 gamma ray 47 fluorescent dye 47 infrared laser 47 UV exposure 47 laser 47 harmful rays 46 ionization 46 laser pulse 46 UVC 46 THz 46 luminance 46 luminosity 46 CCD camera 46 wavelength 46 diffraction 46 unaided eye 46 magnetic fields 45 gamma radiation 45 illumination 45 fluorescence microscopy 45 corona 45 spectra 45 spectrometer 45 light emitting diodes LEDs 45 photosensitive 45 gamma ray burst 45 oxidants 45 UV curing 45 interferometer 45 LED illumination 44 reflective surfaces 44 telescopes 44 spectrophotometer 44 cosmic rays 44 photoelectric 44 phosphors 44 telescope 44 fluorescent proteins 44 extrasolar planet 44 laser beam 44 photodiode 44 laser beams 44 spectrograph 44 ionosphere 44 laser pulses 44 fluoresce 44 sun 44 silicates 44 optically 43 bioluminescence 43 Fluorescence 43 terahertz 43 spectral 43 adaptive optics 43 Orion Nebula 43 celestial objects