If you were able to observe how high the Sun appears at noontime day to day, you would find that over time, the distance that separates the Sun from the horizon changes. In the Northern Hemisphere, the noonday Sun is at its highest on the day of the summer solstice. That very same day, in the Southern Hemisphere, the noonday Sun is at its lowest, it being the winter solstice there. The next day, the Sun at noontime would appear slightly higher in the Southern sky and slightly lower in the Northern, until six months later, the Sun is at its lowest at noontime in the Northern Hemisphere (winter solstice) and at its highest in the Southern (summer solstice.)
At the Equator, the distance between Sun and horizon doesn't change very much throughout the year. At the Poles, however, it changes a great deal -- so much so that during the Northern or Southern winter, the Sun never rises above the horizon, and during the Northern or Southern summer, the Sun never sets below the horizon. It's this latter case that originates the term "midnight sun."
If you remember the movie March of the Penguins there was a sped up time scene showing the Sun barely cresting the horizon, running along it, and then setting, showing the very short winter daylight at the South Pole.
If you are referring to the natural occurence called the Midnight Sun(also known as a Polar day), then it is a phenomenon which occurs during the summer months in areas of the earth near the Arctic and Antarctic circles. During the summer the sun is visible for a full 24 hours, the closer you get to the north and south poles the more days of 24 hour sun you will get. The cause of the phenomenon is the tilting of the earths axis during its orbit around the sun in the summer months. The occurrence of this phenomenon differs in the north and south hemispheres as the summer and winter are opposite.
Midnight Sun is Edward's POV (point of view) of Twilight.
If you are asking about the book, then it's the fifth book in thw twilight series. however, this doesn't tell a new story it simply tells the story of twilight again but from Edward's perspective. This way people reading the books can get a better understanding of the book.
If you don't mean the book then i have no idea.
Midnight Sun is the Twilight story told all over again but in Edward's perspective, not Bella's.
Midnight Sun is related to Twilight and is written in Edward's point of view. I believe it was leaked online so Stephanie Meyer's just put it aside. I am not sure if she will continue to write it but it is highly unlikely.
Midnight Sun is Twilights companion. It features the story of Twilight but in Edward's point of view. Stephanie Meyer has put this piece aside since the manuscript was leaked. It is going to be a while before she decides continue writing it. However she did write a companion to Eclipse which is in the perspective of Bree Tanner, the vampire that the Cullen's let live but the Volturi decided to kill.