Photographer: Larry Gerbrandt aurora borealis, as well as the southern hemisphere, referred to as aurora australis (46 Lerner and Lerner). They appear many different shapes, such as patches of light, rays, arcs, or streamers across the sky. Most commonly, they take the form of curtains of bright colours, such as red, green, blue, and violet (The Columbia Encyclopedia). In Latin, aurora translates to mean ‘dawn’, like the Greek goddess of the same name. Borealis translates to mean ‘north’ or ‘northern wind’, while australis …show more content…
The solar corona is the halo, or outermost layer around the sun, where the temperature can be measured in millions of degrees (65 Bacon). “At this temperature, collisions between gas molecules are frequent and explosive. Free electrons and protons are thrown from the sun's atmosphere by the rotation of the sun and escape through holes in the magnetic field” (The Northern Lights Centre). It is this outer layer which reveals evidence of sun spot activity and coronal holes, as they appear darker in photographs and x-rays of the sun. This corona ejects streams of magnetized plasma, consisting primarily of helium nuclei, protons and electrons (38 Moldwin). For these particles to be able to escape the sun’s gravitational field, they need to have enough energy and be travelling at a fast enough speed. This emission is referred to as a coronal mass ejection (CME). Solar wind, the outward flow from the sun which carries these charged particles, typically moves at speeds between 300 and 800 kilometres per second, meaning that it is able to reach the Earth in roughly 3.9 days (The American Heritage Science …show more content…
These energized particles then follow the magnetic field lines and move towards the north and south polar regions of the Earth’s atmosphere, where they collide with molecules, releasing energy in the form of the aurora lights (64 Bacon). The phenomenon of aurora are an example of luminescent emission, which results in the brilliant display of light. “As the charged particles interact with charged atmospheric gases in Earth's ionosphere, the electrons in the gases move to higher energy states. As the excited electrons return to their ground state, light photons are emitted” (46 Lerner & Lerner). This entire process occurs hundreds of kilometres above earth, with the final result of luminescence appearing most often around 80-100 km, but with some appearing at levels of 500-800 km above earth. The altitude of the aurora has proved to also affect the resulting colour. Green auroras typically occur in areas appear up to 241 kilometres in altitude. Red usually is produced above 250 kilometres. Blue usually appears up to an altitude of roughly 100 kilometres and purple and violet appear above 100 kilometres (Space.com). There are many types of molecules in the Earth’s atmosphere and the colours of