E67 -- Beantwortung verschiedener Fragen über die Beschaffenheit, Bewegung und Würckung der Cometen.

(Answers to various questions about the condition, motion, and effects of comets)

(based on Eric J. Aiton's introduction (written in English) to Opera Omnia Series 2, Volume 31)
Euler published this anonymously when the comet of 1744 appeared. In it, he describes all the aspects of comets of contemporary interest. In particular, he distinguishes comets from fixed stars on the basis of their respective appearances in a telescope. He also argues that the earth must have been similar to a comet at the time of its creation. Euler says that observation alone is not enough to determine whether the solid of a comet rotates and that the tail of a comet is a great collection of dust particles that are driven from the core of the comet by the sun's rays and are then gathered together behind the comet where they reflect sunlight. He urges extreme caution in attributing the appearance of comets to the wrath of God and argues that even though comets can cause perturbations in the earth's orbit, none have come close enough to do so; moreover, none ever will because, if this were to happen, there might be a flood or a destruction of the earth, and the Bible says that this will not happen.


It contains 8 chapters:
  1. Wie die Cometen von andern Sternen zu unterscheiden?
  2. Ob die Cometen feurige Cörper wie die Fixsterne, oder dunckele, wie die Planeten seyn?
  3. Was die Cometen eigentlich für Cörper seyn?
  4. Was von dem Schweif der Cometen zu halten sey?
  5. Wie die Bewegung der Cometen beschaffen sey?
  6. Ob man die Erscheinung der Cometen nicht vorher verkündingen könne?
  7. Wie gross die Anzahl der Cometen sey?
  8. Ob die Cometen einige Würckung auf die Erde haben können?
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