Editing Asteroid (section)

===Discovery of Ceres===
In 1772, German astronomer [[Johann Elert Bode]], citing [[Johann Daniel Titius]], published a numerical procession known as the [[Titius–Bode law]] (now discredited). Except for an unexplained gap between Mars and Jupiter, Bode's formula seemed to predict the orbits of the known planets.<ref name="hoskin" /><ref name="Hogg1948">{{cite journal |last=Hogg |first=Helen Sawyer |title=The Titius-Bode Law and the Discovery of Ceres |journal=Journal of the Royal Astronomical Society of Canada |volume=242 |pages=241–246 |year=1948 |bibcode=1948JRASC..42..241S |url=http://articles.adsabs.harvard.edu//full/1948JRASC..42..241S/0000244.000.html |access-date=18 July 2021 |archive-date=18 July 2021 |archive-url=https://web.archive.org/web/20210718191659/http://articles.adsabs.harvard.edu//full/1948JRASC..42..241S/0000244.000.html |url-status=live }}</ref> He wrote the following explanation for the existence of a "missing planet":

<blockquote>This latter point seems in particular to follow from the astonishing relation which the known six planets observe in their distances from the Sun. Let the distance from the Sun to Saturn be taken as 100, then Mercury is separated by 4 such parts from the Sun. Venus is 4 + 3 = 7. The Earth 4 + 6 = 10. Mars 4 + 12 = 16. Now comes a gap in this so orderly progression. After Mars there follows a space of 4 + 24 = 28 parts, in which no planet has yet been seen. Can one believe that the Founder of the universe had left this space empty? Certainly not. From here we come to the distance of Jupiter by 4 + 48 = 52 parts, and finally to that of Saturn by 4 + 96 = 100 parts.<ref name=discovery>{{cite book |last1=Foderà Serio |first1=G. |last2=Manara |first2=A. |last3=Sicoli |first3=P. |chapter=Giuseppe Piazzi and the Discovery of Ceres |chapter-url=https://www.lpi.usra.edu/books/AsteroidsIII/pdf/3027.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.lpi.usra.edu/books/AsteroidsIII/pdf/3027.pdf |archive-date=2022-10-09 |url-status=live |pages=17–24 |bibcode=2002aste.book...17F |editor1=W. F. Bottke Jr. |editor2=A. Cellino |editor3=P. Paolicchi |editor4=R. P. Binzel |title=Asteroids III |date=2002 |publisher=University of Arizona Press |location=Tucson |isbn=978-0-8165-4651-0}}</ref></blockquote>

Bode's formula predicted another planet would be found with an orbital radius near 2.8 [[astronomical unit]]s (AU), or 420&nbsp;million&nbsp;km, from the Sun.<ref name="Hogg1948" /> The Titius–Bode law got a boost with [[William Herschel]]'s discovery of [[Uranus]] near the predicted distance for a planet beyond [[Saturn]].<ref name="hoskin" /> In 1800, a group headed by [[Franz Xaver von Zach]], editor of the German astronomical journal ''Monatliche Correspondenz'' (Monthly Correspondence), sent requests to 24 experienced astronomers (whom he dubbed the "[[celestial police]]"),<ref name="Hogg1948" /> asking that they combine their efforts and begin a methodical search for the expected planet.<ref name="Hogg1948" /> Although they did not discover Ceres, they later found the asteroids [[2 Pallas]], [[3 Juno]] and [[4 Vesta]].<ref name="Hogg1948" />

One of the astronomers selected for the search was [[Giuseppe Piazzi]], a Catholic [[priest]] at the Academy of Palermo, Sicily. Before receiving his invitation to join the group, Piazzi discovered Ceres on 1 January 1801.<ref name="NASA-20160126">{{cite web |last=Landau |first=Elizabeth |title=Ceres: Keeping Well-Guarded Secrets for 215 Years |url=http://www.jpl.nasa.gov/news/news.php?feature=4824 |date=26 January 2016 |work=NASA |access-date=26 January 2016 |archive-date=24 May 2019 |archive-url=https://web.archive.org/web/20190524043553/https://www.jpl.nasa.gov/news/news.php?feature=4824 |url-status=live }}</ref> He was searching for "the 87th [star] of the Catalogue of the Zodiacal stars of [[Nicolas Louis de Lacaille|Mr la Caille]]",<ref name="hoskin"/> but found that "it was preceded by another".<ref name="hoskin">{{cite web|last=Hoskin |first=Michael |date=26 June 1992 |url=http://www.astropa.unipa.it/HISTORY/hoskin.html |title=Bode's Law and the Discovery of Ceres |publisher=Observatorio Astronomico di Palermo "Giuseppe S. Vaiana" |access-date=5 July 2007 |archive-url=https://web.archive.org/web/20071116022100/http://www.astropa.unipa.it/HISTORY/hoskin.html |archive-date=16 November 2007 |url-status=live }}</ref> Instead of a star, Piazzi had found a moving star-like object, which he first thought was a comet:<ref name="Forbes1971">{{cite journal |last=Forbes |first=Eric G. |title=Gauss and the Discovery of Ceres |journal=Journal for the History of Astronomy |volume=2 |issue=3 |pages=195–199 |year=1971 |bibcode=1971JHA.....2..195F |doi=10.1177/002182867100200305 |s2cid=125888612 |url=http://adsabs.harvard.edu/full/1971JHA.....2..195F |access-date=18 July 2021 |archive-date=18 July 2021 |archive-url=https://web.archive.org/web/20210718200510/http://adsabs.harvard.edu/full/1971JHA.....2..195F |url-status=live }}</ref>

<blockquote>The light was a little faint, and of the colour of [[Jupiter]], but similar to many others which generally are reckoned of the eighth [[Apparent magnitude|magnitude]]. Therefore I had no doubt of its being any other than a fixed star. [...] The evening of the third, my suspicion was converted into certainty, being assured it was not a fixed star. Nevertheless before I made it known, I waited till the evening of the fourth, when I had the satisfaction to see it had moved at the same rate as on the preceding days.<ref name="hoskin"/></blockquote>

Piazzi observed Ceres a total of 24 times, the final time on 11 February 1801, when illness interrupted his work. He announced his discovery on 24 January 1801 in letters to only two fellow astronomers, his compatriot [[Barnaba Oriani]] of Milan and Bode in Berlin.<ref name="cunningham2001">{{cite book |first=Clifford J. |last=Cunningham |title=The first asteroid: Ceres, 1801–2001 |url=https://books.google.com/books?id=CXdMPwAACAAJ |year=2001 |publisher=Star Lab Press |isbn=978-0-9708162-1-4 |access-date=23 October 2015 |archive-date=29 May 2016 |archive-url=https://web.archive.org/web/20160529144326/https://books.google.com/books?id=CXdMPwAACAAJ |url-status=live }}</ref> He reported it as a comet but "since its movement is so slow and rather uniform, it has occurred to me several times that it might be something better than a comet".<ref name="hoskin" /> In April, Piazzi sent his complete observations to Oriani, Bode, and French astronomer [[Jérôme Lalande]]. The information was published in the September 1801 issue of the ''Monatliche Correspondenz''.<ref name="Forbes1971" />

By this time, the apparent position of Ceres had changed (mostly due to Earth's motion around the Sun), and was too close to the Sun's glare for other astronomers to confirm Piazzi's observations. Toward the end of the year, Ceres should have been visible again, but after such a long time it was difficult to predict its exact position. To recover Ceres, mathematician [[Carl Friedrich Gauss]], then 24 years old, developed an [[Gauss's method|efficient method]] of [[orbit determination]].<ref name="Forbes1971" /> In a few weeks, he predicted the path of Ceres and sent his results to von Zach. On 31 December 1801, von Zach and fellow celestial policeman [[Heinrich Wilhelm Matthäus Olbers|Heinrich W. M. Olbers]] found Ceres near the predicted position and thus recovered it.<ref name="Forbes1971" /> At 2.8 AU from the Sun, Ceres appeared to fit the Titius–Bode law almost perfectly; however, Neptune, once discovered in 1846, was 8 AU closer than predicted, leading most astronomers to conclude that the law was a coincidence.<ref>{{cite book|title=The Titius-Bode Law of Planetary Distances: Its History and Theory|url=https://books.google.com/books?id=NneoBQAAQBAJ&q=bode+law+neptune+coincidence+1846&pg=PP1|publisher=Pergamon Press|year=1972|author=Michael Martin Nieto|isbn = 978-1-4831-5936-2|access-date=23 September 2021|archive-date=29 September 2021|archive-url=https://web.archive.org/web/20210929081229/https://books.google.co.uk/books?hl=en&lr=&id=NneoBQAAQBAJ&oi=fnd&pg=PP1&dq=bode+law+neptune+coincidence+1846&ots=LIplNAOXco&sig=qAF2y5xXTivecmSP_fjGCDA9Sx4&redir_esc=y|url-status=live}}</ref> Piazzi named the newly discovered object ''Ceres Ferdinandea,'' "in honor of the [[Ceres (Roman mythology)|patron goddess of Sicily]] and of [[Ferdinand I of the Two Sicilies|King Ferdinand of Bourbon]]".<ref name=discovery/>