The Discourse on Comets (Italian: Discorso delle Comete) was a pamphlet published in 1619 with Mario Guiducci as the named author, though in reality it was mostly the work of Galileo Galilei. In it Galileo conjectured that comets were not physical bodies but atmospheric effects like the aurora borealis.[1]: 62
- ^ Tofigh Heidarzadeh (23 May 2008). A History of Physical Theories of Comets, From Aristotle to Whipple. Springer Science & Business Media. ISBN 978-1-4020-8323-5.