This beautiful image shows the northern lights (aurora borealis) as well as a shooting star (meteor) over Hecla/Grindstone Provincial Park in Manitoba, Canada.
Auroras occur when solar activity in the form of highly charged electrons are blown towards earth in what is called “solar wind”. The electrons interact with elements in the earth’s atmosphere. Solar winds stream away from the sun at speeds of about 1 million miles per hour. When they reach the earth, some 40 hours after leaving the sun, they follow the lines of magnetic force generated by the earth’s core and flow through the magnetosphere.
As the electrons enter the earth’s upper atmosphere, they encounter atoms of oxygen and nitrogen at different altitudes, ranging from 20 to 200 miles above the earth’s surface. The colour of the aurora depends on which atom is first struck and at what altitude. For example, the green colour in this image is the result of electrons interacting with oxygen molecules at an altitude up to 241Km (150 miles).
The meteor on the other hand is visible as a result of what is called ram pressure; the pressure exerted on a body which is moving through a fluid medium, like air. As the meteorite is soaring through the atmosphere a shock wave is formed as a result of the compression of air. This in turn heats the air and subsequently heats the meteor as it flows around it. The intense heat vaporizes most meteors, creating what we call shooting stars, as in this image.
Picture courtesy of Federico Buchbinder