This image shows filaments of ionized gas in the proximity of the R136 cluster, which lies beyond the lower left edge of the photo. The different hues are due to different physical conditions that manifest themselves in the spectrum of the light emitted by the gas. Note also the dark lanes running roughly from bottom left to upper right, which are due to filaments of obscuring dust seen in projection against the background of bright nebulosity. The sky field measures 6.5 x 5.7 arcmin. North is up and East is left.
The marvellous richness of the filament colours is due to the varying conditions in the interstellar gas in this region, cf. PR Photo 34b/04. The red in these images is caused by emission of excited hydrogen atoms, the green shades correspond to emission from oxygen atoms from which two electrons ("doubly-ionized oxygen") have been "knocked off" by the energetic radiation of hot stars in the R136 cluster, that is located beyond the lower right corner of this photo. The intensity of this emission increases towards R136, explaining the yellowish colour near the edge of the photo.
A blue colour is contributed by singly-ionized atoms of oxygen. Other atoms like nitrogen and sulfur at different levels of ionization also add to the emission of the nebula at specific wavelengths. The observed colours thus probe the physical condition of the emitting gas and the temperature of the star(s) that excite(s) it. The intricate appearance of the filaments is mostly a consequence of turbulence in the interstellar gas, of the magnetic fields, and of the energy input by the massive stars in the neighbourhood.