Lagoon Nebula. Optical image of tornado-like structures (upper centre & lower left) in the Lagoon Nebula (Messier 8) which lies in the Sagittarius constellation. The dusty gas (brown) of the Nebula is being ionised by radiation from nearby, hot stars, including O Herschel 36 (bright red, lower right). This is causing a blue mist to evaporate from the Nebula's surface. The temperature difference between the hot surface and cool interior of the Nebula, combined with the radiation pressure from the stars, produces strong, shearing forces which twist the clouds into tornados. Image by the Hubble Telescope.