Blue jets are a highly enigmatic high altitude optical phenomenon and were first documented on October 21, 1989, from the Space Shuttle as it passed over Australia.
This type of elusive transient luminous events are optical ejections from the top of the electrically active core regions of thunderstorms. And as their name implies, they are blue in color.
However, they are not directly associated with cloud-to-ground lightning. By 2007, fewer than a hundred images had been obtained.
Following their emergence from the top of the thundercloud, they typically propagate upward in narrow cones of about 15 degrees.
They fan out and disappear at heights of about 25-30 miles (40-50 km) with a lifetime of a couple of tenths of a second.
The color is believed to be due to a set of blue and near-ultraviolet emission lines from neutral and ionized molecular nitrogen.
Pictures of the blue jets above this thunderstorm cell over Darwin were shot from a distance of about 100km by William Nguyen Phuoc. Visit his website ntwildscapes.com as well as his Flickr and 500px pages.