Editing 1618 in science (section)

==Astronomy==
* March 8 – May 15 – [[Johannes Kepler]] formulates the [[Kepler's laws of planetary motion|third law of planetary motion]].<ref>{{cite book|first=Arthur I.|last=Miller|title=Deciphering the cosmic number: the strange friendship of Wolfgang Pauli and Carl Jung|url=https://archive.org/details/isbn_9780393065329|url-access=registration|accessdate=March 7, 2011|date=2009|location=New York|publisher=W. W. Norton & Co.|isbn=978-0-393-06532-9|page=[https://archive.org/details/isbn_9780393065329/page/80 80]}}</ref>
* July 21 – [[Pluto]] (not known at this time) reaches an [[aphelion]]. It next comes to aphelion in [[1866 in science|1866]].
* [[Johann Baptist Cysat]], [[Swiss people|Swiss]] [[Jesuits|Jesuit]] geometer and [[astronomer]] and one of [[Christoph Scheiner]]'s pupils, becomes the first to study a [[comet]] through the telescope and gives the first description of the [[Comet nucleus|nucleus]] and [[Coma (cometary)|coma]] of a comet.
* September 6–25 – The [[C/1618 W1|Great Comet of 1618]] is visible to the naked eye. [[James VI and I|James I]] described it as "Venus with a firebrand in her arse".<ref>{{cite book |last1=Ereira |first1=Alan |title=The Nine Lives of John Ogilby |date=2016 |publisher=Duckworth |isbn=9780715652268 |page=xxi}}</ref>