NASA: It is a rare encounter of two of the most beautiful phenomena on Earth. This is the meeting of sunrise with the northern saddle, over the northeast coast of the American continent.
The video captured her last Thursday astronaut NASA Barry "Butch" Wilmore, while on orbit over the states of Virginia, Delaware, New Jersey, New York and Massachusetts, on the eastern coast of the United States.
Both North and South are most commonly observed along a zone whose center is from the poles of approximately 10 degrees. While just above the poles they appear much thinner.
Its color depends on which gas - oxygen or nitrogen - is produced by the electrons. It also depends on how fast the electrons move.