Editing Comet (section)

=== Great comets ===
{{Main|Great comet}}{{See also|Great Comet of 1577}}
[[File:Von einem Schrecklichen vnd Wunderbarlichen Cometen so sich den Dienstag nach Martini dieses lauffenden M. D. Lxxvij. Jahrs am Himmel erzeiget hat (grayscale).png|thumb|300px|Woodcut of the [[Great Comet of 1577]]]]

Approximately once a decade, a comet becomes bright enough to be noticed by a casual observer, leading such comets to be designated as great comets.<ref name="great"/> Predicting whether a comet will become a great comet is notoriously difficult, as many factors may cause a comet's brightness to depart drastically from predictions.<ref>{{cite book |url=https://books.google.com/books?id=vQwwAAAAMAAJ |page=274 |title=The World Almanac and Book of Facts 1996 |isbn=978-0-88687-780-4 |last=Famighetti |first=Robert |date=1995|publisher=Newspaper Enterprise Association }}</ref> Broadly speaking, if a comet has a large and active nucleus, will pass close to the Sun, and is not obscured by the Sun as seen from Earth when at its brightest, it has a chance of becoming a great comet. However, [[Comet Kohoutek]] in 1973 fulfilled all the criteria and was expected to become spectacular but failed to do so.<ref>{{cite web |url=http://www.universetoday.com/97561/new-sun-skirting-comet-could-provide-dazzling-display-in-2013/ |title=New 'Sun-Skirting' Comet Could Provide Dazzling Display in 2013 |work=Universe Today |access-date=7 September 2013 |last=Atkinson |first=Nancy|date=25 September 2012 }}</ref> [[Comet West]], which appeared three years later, had much lower expectations but became an extremely impressive comet.<ref>{{cite web |last=Kronk |first=Gary W. |title=C/1975 V1 (West) |url=http://cometography.com/lcomets/1975v1.html |work=Gary W. Kronk's Cometography |access-date=7 September 2013}}</ref>

The Great Comet of 1577 is a well-known example of a great comet. It passed near Earth as a [[List of near-parabolic comets|non-periodic comet]] and was seen by many, including well-known astronomers Tycho Brahe and [[Taqi ad-Din Muhammad ibn Ma'ruf|Taqi ad-Din]]. Observations of this comet led to several significant findings regarding cometary science, especially for Brahe.

The late 20th century saw a lengthy gap without the appearance of any great comets, followed by the arrival of two in quick succession—[[Comet Hyakutake]] in 1996, followed by [[Hale–Bopp]], which reached maximum brightness in 1997 having been discovered two years earlier. The first great comet of the 21st century was [[C/2006 P1]] (McNaught), which became visible to naked eye observers in January 2007. It was the brightest in over 40 years.<ref>{{cite web |url=http://hubblesite.org/hubble_discoveries/comet_ison/blogs/great-moments-in-comet-history-comet-mcnaught |title=Great Moments in Comet History: Comet McNaught |publisher=Hubblesite |access-date=15 August 2013}}</ref>