Physical investigations on the cause of the tails of comets, the northern lights, and the zodiacal light
Euler rejects the view of de Mairan that the zodiacal light is the cause of the tails of comets and the northern lights; instead, Euler argues that zodiacal light is the result of particles emanating from the Sun, the tails of comets are the result of particles emanating from the bodies of the comets, and that the northern lights are the result of particles emanating from the Earth. He also says that the tails of comets are different because of the motions of the comets and that planets lack tails because of the small extent of their atmospheres. Euler also infers the existence of a solar atmosphere from the existence of sunspots. In addition, he says that the zodiacal light is the view of the solar atmosphere extended about the equator of the Earth. He calculates the form of the solar atmosphere and arrives at a cubic equation. Euler asserts that this equation implies that the atmosphere must have the form of a ring. (Based on Eric Aiton's introduction to Opera Omnia Series II, Volume 31.)
Original Source Citation
Mémoires de l'académie des sciences de Berlin, Volume 1748, pp. 117-140.
Opera Omnia Citation
Series 2, Volume 31, pp.221-238.