E103 -- Recherches physiques sur la cause de la queüe des cometes, de la lumiere boreale, et de la lumiere zodiacale
(Physical Investigations on the tail of comets, the northern lights, and the zodiacal light)
(based on Eric J. Aiton's introduction (written in English) to Opera Omnia Series 2, Volume 31)
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 is the result of particles emanating from the bodies of the comets, and that the northern lights
is 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 sun-spots.
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.
Originally published in Mémoires de l'académie des sciences de Berlin in 1746, pp. 117-140
Opera Omnia: Series 2, Volume 31, pp. 221 - 238
- Reprinted in OEuvres complètes d’Euler 2, 1839, pp. 344-361 [E103a]
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