A stunning blue light likely caused by SpaceX Falcon 9 rocket fuel illuminated the night skies over Europe on Monday.

Complicated physics makes these molecules scatter more blue light than red ... far removed from humanity’s wasted sky-directed light, that background can be as dim as 22 mag/arcsec 2.

This scatters the blue and green light along the way ... you can see the blue sky fade away to a black background as it climbs above the atmosphere.

The appearance of an extraordinary spiral of blue light in the sky above New Zealand has prompted amazement among stargazers - and theories ranging from aliens to black holes. Astronomer Alasdair ...