English Title

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


Leonhard Euler

Enestrom Number


Fuss Index


Original Language


Archive Notes

Published anonymously.

Content Summary

Euler published this tract 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. (Based on Eric Aiton's introduction to Opera Omnia Series II, Volume 31.)

Published as

Octavo book

Published Date


Written Date


Original Source Citation

Berlin: Ambrosius Haude, pp. 1-56.

Opera Omnia Citation

Series 2, Volume 31, pp.125-150.

Record Created