The Aurora Borealis or Northern Lights were named by the French scientist, Pierre Gassendi, in 1621. They were named Aurora for the Roman goddess of the dawn (known as Eos and usually described as "rosy-fingered" by the Greeks) and for the god of the North wind Boreas in Latin.
The colour spectrum of the Northern lights is determined by the gases with which the particles from the sun collide and by the altitude at which the collision takes place in the atmosphere.
These are examples of the Auroras Borealis or Northern lights which occur from 90 km to approximately 150 km above the Earth's surface. The colours can be categorised more or less as follows:
- More than 150 km: Red light
- 120 km - 150 km: Yellow-Green light
- Less than 120 km: Blue-Purple lightAnd the Coronal Auroras.
