History of astronomy: Difference between revisions

{{multiple issues|{{Lead too short|date=August 2023}}{{More citations needed|date=April 2025}}}}[[File:Ioannis Bayeri Rhainani Vranometria 1661 (84132277) (cropped).jpg|thumb|upright=1.35|A map of the [[northern celestial hemisphere]] from [[Johann Bayer]]'s 1661 edition of ''[[Uranometria]]'', the first [[atlas]] to feature [[star chart]]s covering the entire [[celestial sphere]]]]

The '''history of astronomy''' focuses on the efforts of civilizations to understand the [[universe]] beyond earth's atmosphere. [[Astronomy]] is one of the oldest [[natural sciences]], achieving a high level of success in the second half of the first millennium. Astronomy has origins in the [[religious]], [[mythological]], [[cosmological]], calendrical, and [[astrological]] beliefs and practices of prehistory. Early astronomical records date back to the [[Babylonians]] around 1000 BC. There is also astronomical evidence of interest from early Chinese, Central American and North European cultures.<ref>{{cite web | url=https://pages.uoregon.edu/jschombe/ast121/lectures/lec02.html | title=History of Astronomy }}</ref>

Astronomy was used by early [[cultures]] for timekeeping, [[navigation]], spiritual and religious practices, and agricultural planning. Ancient astronomers observed and charted the skies in an effort to learn about the workings of the universe. During the [[Renaissance]] Period, revolutionary ideas emerged about astronomy. One such idea was contributed in 1543 by Polish astronomer [[Nicolaus Copernicus]], who developed a heliocentric model that depicted the planets orbiting the Sun. This was the start of the [[Copernican Revolution]],<ref>{{cite web | url=https://www.asc-csa.gc.ca/eng/astronomy/basics/brief-history-astronomy.asp | title=A brief history of astronomy | date=12 March 2020 }}</ref> with the invention of the [[telescope]] in 1608 playing a key part. Later developments included the [[reflecting telescope]], [[astronomical photography]], [[astronomical spectroscopy]], [[radio telescopes]], [[cosmic ray astronomy]], [[infrared telescopes]], [[space telescopes]], [[ultraviolet astronomy]], [[X-ray astronomy]], [[gamma-ray astronomy]], [[space probes]], [[neutrino astronomy]], and [[gravitational-wave astronomy]].

The success of astronomy, compared to other sciences, was achieved for several reasons. Astronomy was the first science to have a mathematical foundation. Standardized measuring instruments such as [[armillary spheres]] and quadrants provided a solid base for collecting, verifying and communicating data.<ref>{{cite journal | url=https://academic.oup.com/astrogeo/article/51/3/3.25/224270#94074640 | doi=10.1111/j.1468-4004.2010.51325.x | title=The impact of astronomy | date=2010 | last1=Fabian | first1=Andy | journal=Astronomy & Geophysics | volume=51 | issue=3 | pages=3.25–3.30 | bibcode=2010A&G....51c..25F }}</ref><ref>{{cite web | url=https://www.britannica.com/science/astronomy/History-of-astronomy | title=Astronomy - Ancient, Celestial, Observations |publisher=Encyclopedia Britannica }}</ref> Throughout the years, astronomy has broadened into multiple subfields such as [[astrometry]], [[Planetary science|planetary astronomy]], [[astrophysics]], [[astrochemistry]] [[astrobiology]], [[stellar astronomy]], [[galactic astronomy]], [[extragalactic astronomy]], and [[physical cosmology]]<ref>{{cite web | url=https://www.space.com/16014-astronomy.html#section-history-of-astronomy-the-beginnings | title=Astronomy: Everything you need to know | website=[[Space.com]] | date=28 October 2022 }}</ref>

 

A 32,500-year-old carved ivory [[mammoth]] tusk could contain the oldest known star chart (resembling the [[constellation]] [[Orion (constellation)|Orion]]).<ref>{{cite news

   | url=https://news.bbc.co.uk/2/hi/science/nature/2679675.stm | access-date=2009-09-29}}</ref> It has also been suggested that drawings on the wall of the [[Lascaux]] caves in France dating from 33,000 to 10,000 years ago could be a graphical representation of the [[Pleiades]], the [[Summer Triangle]], and the [[Northern Crown]].<ref>{{cite news

   | url=https://www.space.com/scienceastronomy/planetearth/cave_paintings_000810.html

   | access-date=2009-09-29}}</ref><ref>{{cite web|url=https://news.bbc.co.uk/1/hi/sci/tech/871930.stm|title=BBC News – SCI/TECH – Ice Age star map discovered|website=news.bbc.co.uk|access-date=13 April 2018}}</ref> Ancient structures with possibly [[Archaeoastronomy#Alignments|astronomical alignments]] (such as [[Stonehenge]]) probably fulfilled astronomical, [[religion|religious]], and [[social function]]s.

* Paleolithic archaeologist [[Alexander Marshack]] put forward a theory in 1972 that bone sticks from locations like Africa and Europe from possibly as long ago as 35,000 BC could be marked in ways that tracked the Moon's phases,<ref>{{cite book|last = Marshak|first =  Alexander|date =1972|publisher = Littlehampton Book Services |title = The Roots of Civilization: the cognitive beginnings of man's first art, symbol, and notation|isbn = 978-0297994497}}</ref>{{page needed|date=January 2019}} an interpretation that has met with criticism.<ref>{{cite journal|last = Davidson|first =  Iain|date =1993|publisher = American Anthropologistd|title = The Roots of Civilization: The Cognitive Beginnings of Man's First Art, Symbol and Notation|journal=American Anthropologist|volume=95|number=4|pages=1027–1028|doi=10.1525/aa.1993.95.4.02a00350}}</ref>

* [[Goseck circle]] is located in [[Germany]] and belongs to the [[linear pottery culture]]. First discovered in 1991, its significance was only clear after results from archaeological digs became available in 2004. The site is one of hundreds of similar [[circular enclosure]]s built in a region encompassing [[Austria]], Germany, and the [[Czech Republic]] during a 200-year period starting shortly after 5000&nbsp;BC.<ref>{{cite news|url=https://www.sonnenobservatorium-goseck.info/|title=Sonnenobservatorium Goseck|archive-date=2025-11-11|access-date=2025-11-06|archive-url=https://web.archive.org/web/20251111044109/https://sonnenobservatorium-goseck.info/|url-status=dead}}</ref>

* The [[Nebra sky disk|Nebra sky disc]] is a [[Bronze Age]] bronze disc that was buried on [[Mittelberg (Rhön)|Mittenberg hill]] in Germany around 1600&nbsp;BC.<ref>{{Cite journal |last=Pernicka |first=Ernst |last2=Adam |first2=Jörg |last3=Borg |first3=Gregor |last4=Brügmann |first4=Gerhard |last5=Bunnefeld |first5=Jan-Heinrich |last6=Kainz |first6=Wolfgang |last7=Klamm |first7=Mechthild |last8=Koiki |first8=Thomas |last9=Meller |first9=Harald |last10=Schwarz |first10=Ralf |last11=Stöllner |first11=Thomas |last12=Wunderlich |first12=Christian-Heinrich |last13=Reichenberger |first13=Alfred |date=2020 |title=Why the Nebra Sky Disc Dates to the Early Bronze Age. An Overview of the Interdisciplinary Results |url=https://www.jstor.org/stable/27045107 |journal=Archaeologia Austriaca |volume=104 |pages=89–122 |issn=0003-8008}}</ref> It measures about {{Convert|30|cm|abbr=on}} diameter with a mass of {{Convert|2.2|kg|abbr=on}} and displays a blue-green patina (from oxidization) inlaid with gold symbols. Found by archeological thieves in 1999 and recovered in Switzerland in 2002, it was soon recognized as a spectacular discovery, among the most important of the 20th century.<ref>{{citation |title=The Nebra Sky Disc |publisher=Landesamt für Denkmalpflege und Archäologie Sachsen-Anhalt / Landesmuseum für Vorgeschichte |url=http://www.lda-lsa.de/en/nebra_sky_disc/ |access-date=15 October 2014 |archive-date=12 April 2014 |archive-url=https://web.archive.org/web/20140412185921/http://www.lda-lsa.de/en/nebra_sky_disc |url-status=dead }}</ref><ref>{{citation |title=Nebra Sky Disc |publisher=UNESCO Memory of the World Programme |url=https://www.unesco.org/en/memory-world/nebra-sky-disc |access-date=2025-04-22}}</ref> Investigations revealed that the object had been in use around 400 years before burial (2000 BC), but that its use had been forgotten by the time of burial. The inlaid gold depicted the full moon, a crescent moon about 4 or 5 days old, and the [[Pleiades]] star cluster in a specific arrangement, forming the earliest known depiction of celestial phenomena. Twelve lunar months pass in 354 days, requiring a calendar to insert a leap month every two or three years in order to keep synchronized with the solar year's seasons (making it [[Lunisolar calendar|lunisolar]]). The earliest known descriptions of this coordination were recorded by the Babylonians in the sixth or seventh centuries BC, over one thousand years later. Those descriptions verified ancient knowledge of the Nebra sky disc's celestial depiction as the precise arrangement needed to judge when to insert the [[Intercalation (timekeeping)|intercalary month]] into a lunisolar calendar, making it an astronomical clock for regulating such a calendar a thousand or more years before any other known method.<ref>{{citation |title=The Sky Disc of Nebra: Bronze Age Sky Disc Deciphered |publisher=Deutsche Welle |date=2002 |url=https://www.bibliotecapleyades.net/arqueologia/nebra_disk.htm |access-date=15 October 2014}}</ref>

The first evidence of recognition that astronomical phenomena are periodic and of the application of mathematics to their prediction is Babylonian. Tablets dating back to the [[First Babylonian dynasty|Old Babylonian period]] document the application of mathematics to the variation in the length of daylight over a solar year. Centuries of Babylonian observations of celestial phenomena are recorded in the series of [[cuneiform]] tablets known as the ''[[Enūma Anu Enlil]]''. The oldest significant astronomical text that we possess is Tablet 63 of the ''Enūma Anu Enlil'', the [[Venus tablet of Ammisaduqa|Venus tablet]] of [[Ammi-saduqa]], which lists the first and last visible risings of Venus over a period of about 21 years and is the earliest evidence that the phenomena of a planet were recognized as periodic. The [[MUL.APIN]] contains catalogues of stars and constellations as well as schemes for predicting [[heliacal rising]]s and the settings of the planets, lengths of daylight measured by a [[water clock]], [[gnomon]], shadows, and [[Intercalation (timekeeping)|intercalations]]. The Babylonian GU text arranges stars in 'strings' that lie along declination circles and thus measure right-ascensions or time-intervals, and also employs the stars of the zenith, which are also separated by given right-ascensional differences.<ref name=Pingree1998/><ref>{{cite book |last=Evans |first=James |year=1998 |title=The History and Practice of Ancient Astronomy |publisher=Oxford University Press |isbn=0-19-509539-1}}</ref><ref>{{Cite book |last=Rochberg |first=Francesca |title=The heavenly writing: divination, horoscopy, and astronomy in Mesopotamian culture |date=2004 |publisher=Cambridge University Press |isbn=978-0-511-61740-9 |location=Cambridge New York}}</ref>

Babylonian astronomy was the basis for much of what was done in [[Greek astronomy|Greek and Hellenistic astronomy]], in classical [[Indian astronomy]], in Sassanian Iran, in Byzantium, in Syria, in [[Islamic astronomy]], in Central Asia, and in Western Europe.<ref name="Pingree1998">{{cite book |last=Pingree |first=David |author-link=David Pingree |date=1998 |contribution=Legacies in Astronomy and Celestial Omens |editor-last=Dalley |editor-first=Stephanie |editor-link=Stephanie Dalley |title=The Legacy of Mesopotamia |publisher=Oxford University Press |pages=125–137 |isbn =0-19-814946-8}}</ref>

[[Aryabhata]] (476–550), in his magnum opus ''[[Aryabhatiya]]'' (499), propounded a computational system based on a planetary model in which the Earth was taken to be [[Earth's rotation|spinning on its axis]] and the periods of the planets were given with respect to the Sun. He accurately calculated many astronomical constants, such as the periods of the planets, times of the [[solar eclipse|solar]] and [[lunar eclipse|lunar]] [[eclipse]]s, and the instantaneous motion of the Moon.<ref name="Joseph-2000"/><ref>Thurston, H, ''Early Astronomy.'' Springer, 1994, p. 178–188.</ref>{{Page needed|date=September 2010}} Early followers of Aryabhata's model included [[Varāhamihira]], [[Brahmagupta]], and [[Bhāskara II]].

In the 3rd century BC [[Aristarchus of Samos]] was the first to suggest a [[heliocentric]] system, although only fragmentary descriptions of his idea survive.<ref name=Pederson-1993/>{{rp|p=55–6}} [[Eratosthenes]] estimated the [[circumference of the Earth]] with great accuracy (see also: [[history of geodesy]]).<ref name=Pederson-1993>{{cite book |author-link=Olaf Pedersen |last=Pedersen |first=Olaf |year=1993 |title=Early Physics and Astronomy: A Historical Introduction |edition=rev. |publisher=Cambridge University Press |isbn=0-521-40899-7}}</ref>{{rp|45}}

[[Maya civilization|Maya]] astronomical [[Maya codices|codices]] include detailed tables for calculating [[Lunar phases|phases of the Moon]], the recurrence of eclipses, and the appearance and disappearance of [[Venus]] as morning and [[Venus#Observability|evening star]]. The Maya based their [[Maya calendar|calendrics]] in the carefully calculated cycles of the [[Pleiades]], the [[Sun]], the [[Moon]], [[Venus]], [[Jupiter]], [[Saturn]], [[Mars]], and also they had a precise description of the eclipses as depicted in the [[Dresden Codex]], as well as the ecliptic or zodiac, and the [[Milky Way]] was crucial in their Cosmology.<ref>[http://www.authenticmaya.com/maya_astronomy.htm Maya Astronomy] {{webarchive|url=https://web.archive.org/web/20070606210812/http://www.authenticmaya.com/maya_astronomy.htm|date=2007-06-06}}</ref> A number of important Maya structures are believed to have been oriented toward the extreme risings and settings of Venus. To the ancient Maya, Venus was the patron of war and many recorded battles are believed to have been timed to the motions of this planet. Mars is also mentioned in preserved astronomical codices and early [[Maya mythology|mythology]].<ref name=Aveni-1980>{{cite book |last=Aveni |first=Anthony F. |title=Skywatchers of Ancient Mexico |publisher=University of Texas Press |year=1980 |isbn=0-292-77557-1}}</ref>{{rp|173}}

Although the [[Maya calendar]] was not tied to the Sun, [[John E. Teeple|John Teeple]] has proposed that the Maya calculated the [[tropical year|solar year]] to somewhat greater accuracy than the [[Gregorian calendar]].<ref name=Aveni-1980/>{{rp|170}} Both astronomy and an intricate numerological scheme for the measurement of time were vitally important components of [[Maya civilization#Religion|Maya religion]].

[[File:Astrolabio di ahmad ibn muhammad al-naqqash, ottone inciso, saragozza, 1079-1080.jpg|thumb|Arabic [[astrolabe]] from 1079 to 1080&nbsp;AD]]

In the ninth century, Persian astrologer [[Albumasar]] was thought to be one of the greatest astrologer at that time. His practical manuals for training astrologers profoundly influenced Muslim intellectual history and, through translations, that of western Europe and Byzantium In the 10th century,<ref>{{cite encyclopedia | last = Pingree | first = David | title = Abū Ma'shar al-Balkhī, Ja'far ibn Muḥammad | encyclopedia = [[Dictionary of Scientific Biography]] | volume = 1 | pages = 32–39 | publisher = [[Charles Scribner's Sons]] | location = New York | year = 1970 | isbn = 0-684-10114-9 | url = https://www.encyclopedia.com/doc/1G2-2830900030.html}}</ref> Albumasar's "Introduction" was one of the most important sources for the recovery of Aristotle for medieval European scholars.<ref>Richard Lemay, ''Abu Ma'shar and Latin Aristotelianism in the Twelfth Century, The Recovery of Aristotle's Natural Philosophy through Iranian Astrology'', 1962.</ref> [[Abd al-Rahman al-Sufi]] (Azophi) carried out observations on the [[star]]s and described their positions, [[apparent magnitude|magnitude]]s, brightness, and [[colour]] and drawings for each constellation in his ''[[Book of Fixed Stars]]''. He also gave the first descriptions and pictures of "A Little Cloud" now known as the [[Andromeda Galaxy]]. He mentions it as lying before the mouth of a Big Fish, an Arabic [[constellation]]. This "cloud" was apparently commonly known to the [[Isfahan (city)|Isfahan]] astronomers, very probably before 905&nbsp;AD.<ref name="NSOG">{{Citation |last1= Kepple |first1= George Robert | first2 = Glen W. | last2 = Sanner |title= The Night Sky Observer's Guide, Volume 1 |publisher= Willmann-Bell, Inc. |date= 1998 |isbn= 0-943396-58-1 |pages=18}}</ref> The first recorded mention of the [[Large Magellanic Cloud]] was also given by al-Sufi.<ref name="obspm">{{cite web  | title=Observatoire de Paris (Abd-al-Rahman Al Sufi)  | url=https://messier.obspm.fr/xtra/Bios/alsufi.html  | access-date=2007-04-19}}</ref><ref name="obspm2">{{cite web  | publisher =Observatoire de Paris|title = The Large Magellanic Cloud, LMC  | url=https://messier.obspm.fr/xtra/ngc/lmc.html  |date = 11 March 2004}}</ref> In 1006, [[Ali ibn Ridwan]] observed [[SN 1006]], the brightest [[supernova]] in recorded history, and left a detailed description of the temporary star.

In the late tenth century, a huge observatory was built near [[Tehran]], [[Iran]], by the astronomer [[Abu-Mahmud al-Khujandi]] who observed a series of [[Meridian (astronomy)|meridian]] [[Astronomical transit|transits]] of the Sun, which allowed him to calculate the tilt of the Earth's axis relative to the Sun. He noted that measurements by earlier (Indian, then Greek) astronomers had found higher values for this angle, possible evidence that the axial tilt is not constant but was in fact decreasing.<ref>[https://www.encyclopedia.com/doc/1G2-2830902295.html Al-Khujandi, Abu Ma?mud ?amid Ibn Al-Khi?r], ''Complete Dictionary of Scientific Biography'', 2008.</ref><ref>{{MacTutor|id=Al-Khujandi|title=Abu Mahmud Hamid ibn al-Khidr Al-Khujandi}}</ref> In 11th-century Persia, [[Omar Khayyám]] compiled many tables and performed a reformation of the [[calendar]] that was more accurate than the [[Julian Calendar|Julian]] and came close to the [[Gregorian calendar|Gregorian]].

Other important astronomers from India include [[Madhava of Sangamagrama]], [[Nilakantha Somayaji]] and [[Jyeshtadeva]], who were members of the [[Kerala school of astronomy and mathematics]] from the 14th century to the 16th century. Nilakantha Somayaji, in his ''Aryabhatiyabhasya'', a commentary on Aryabhata's ''Aryabhatiya'', developed his own computational system for a partially [[heliocentrism|heliocentric]] planetary model, in which Mercury, Venus, [[Mars]], [[Jupiter]] and [[Saturn]] orbit the [[Sun]], which in turn orbits the [[Earth]], similar to the [[Tychonic system]] later proposed by [[Tycho Brahe]] in the late 16th century. Nilakantha's system, however, was mathematically more efficient than the Tychonic system, due to correctly taking into account the equation of the centre and [[latitude|latitudinal]] motion of Mercury and Venus. Most astronomers of the [[Kerala school of astronomy and mathematics]] who followed him accepted his planetary model.<ref name="Joseph-2000">{{cite book |first=George G. |last=Joseph |year=2000 |title=The Crest of the Peacock: Non-European Roots of Mathematics |edition=2nd |publisher=Penguin Books |place=London |isbn=0-691-00659-8}}{{rp|p=408}}.</ref><ref>{{cite journal |last1=Ramasubramanian |first1=K. |last2=Srinivas |first2=M. D. |last3=Sriram |first3=M. S. |year=1994 |title=Modification of the earlier Indian planetary theory by the Kerala astronomers (c. 1500 AD) and the implied heliocentric picture of planetary motion |journal=[[Current Science]] |volume=66 |pages=784–790}}</ref>

After the significant contributions of Greek scholars to the development of astronomy, it entered a relatively static era in Western Europe from the Roman era through the 12th century. This lack of progress has led some astronomers to assert that nothing happened in Western European astronomy during the Middle Ages.<ref>Henry Smith Williams, ''The Great Astronomers'' (New York: Simon and Schuster, 1930), pp. 99–102 describes "the record of astronomical progress" from the Council of Nicea (325 AD) to the time of Copernicus (1543 AD) on four blank pages.</ref>  Recent investigations, however, have revealed a more complex picture of the study and teaching of astronomy in the period from the 4th to the 16th centuries.<ref name=McCluskey-1998>{{cite book |last=McCluskey |first=Stephen C. |title=Astronomies and Cultures in Early Medieval Europe |publisher=Cambridge University Press |year=1998 |isbn=0-521-77852-2}}</ref>

[[Western Europe]] entered the Middle Ages with great difficulties that affected the continent's intellectual production. The advanced astronomical treatises of [[classical antiquity]] were written in [[Greek language|Greek]], and with the decline of knowledge of that language, only simplified summaries and practical texts were available for study. The most influential writers to pass on this ancient tradition in [[Latin]] were [[Macrobius]], [[Pliny the Elder|Pliny]], [[Martianus Capella]], and [[Calcidius]].<ref>Bruce S. Eastwood, ''Ordering the Heavens: Roman Astronomy and Cosmology in the Carolingian Renaissance'', (Leiden: Brill, 2007) {{ISBN|978-90-04-16186-3}}.</ref>  In the 6th century Bishop [[Gregory of Tours]] noted that he had learned his astronomy from reading Martianus Capella, and went on to employ this rudimentary astronomy to describe a method by which monks could determine the time of prayer at night by watching the stars.<ref name=McCluskey-1998/>{{rp|p=101}}

The range of surviving ancient Roman writings on astronomy and the teachings of Bede and his followers began to be studied in earnest during the [[Carolingian Renaissance|revival of learning]] sponsored by the emperor [[Charlemagne]].<ref name=McCluskey-1998/>{{rp|p=131}} By the 9th century rudimentary techniques for calculating the position of the planets were circulating in Western Europe; medieval scholars recognized their flaws, but texts describing these techniques continued to be copied, reflecting an interest in the motions of the planets and in their astrological significance.<ref>David Juste, "Neither Observation nor Astronomical Tables: An Alternative Way of Computing the Planetary Longitudes in the Early Western Middle Ages," pp. 181–222 in Charles Burnett, Jan P. Hogendijk, [[Kim Plofker]], and Michio Yano, ''Studies in the Exact Sciences in Honour of David Pingree'', (Leiden: Brill, 2004)</ref>

Building on this astronomical background, in the 10th century European scholars such as [[Gerbert of Aurillac]] began to travel to Spain and Sicily to seek out learning which they had heard existed in the Arabic-speaking world. There they first encountered various practical astronomical techniques concerning the calendar and timekeeping, most notably those dealing with the [[astrolabe]]. Soon scholars such as [[Hermann of Reichenau]] were writing texts in Latin on the uses and construction of the astrolabe and others, such as [[Walcher of Malvern]], were using the astrolabe to observe the time of eclipses in order to test the validity of computistical tables.<ref name=McCluskey-1998/>{{rp|p=171}}

By the 12th century, scholars were traveling to Spain and Sicily to seek out more advanced astronomical and astrological texts, which they [[Latin translations of the 12th century|translated into Latin]] from Arabic and Greek to further enrich the astronomical knowledge of Western Europe. The arrival of these new texts coincided with the rise of the universities in medieval Europe, in which they soon found a home.<ref name=McCluskey-1998/>{{rp|p=188}} Reflecting the introduction of astronomy into the universities, [[Johannes de Sacrobosco|John of Sacrobosco]] wrote a series of influential introductory astronomy textbooks: the [[De sphaera mundi|Sphere]], a Computus, a text on the [[Quadrant (instrument)|Quadrant]], and another on Calculation.<ref>{{cite journal | last1 = Pedersen | first1 = Olaf | year = 1985 | title = In Quest of Sacrobosco | journal = Journal for the History of Astronomy | volume = 16 | issue = 3 | pages = 175–221 |bibcode = 1985JHA....16..175P | doi = 10.1177/002182868501600302 | s2cid = 118227787}}</ref>

During the renaissance period, astronomy began to undergo a revolution in thought known as the [[Copernican Revolution]], which gets the name from the astronomer [[Nicolaus Copernicus]], who proposed a heliocentric system, in which the planets revolved around the Sun and not the Earth. His ''[[De revolutionibus orbium coelestium]]'' was published in 1543.<ref name="Westman">Westman, Robert S. (2011). ''The Copernican Question: Prognostication, Skepticism, and Celestial Order''. Los Angeles: University of California Press. {{ISBN|9780520254817}}.</ref> While in the long term this was a very controversial claim, in the very beginning it only brought minor controversy.<ref name="Westman" /> The theory became the dominant view because many figures, most notably [[Galileo Galilei]], [[Johannes Kepler]] and [[Isaac Newton]] championed and improved upon the work. Other figures also aided this new model despite not believing the overall theory, like [[Tycho Brahe]], with his well-known observations.<ref name="John Louis Emil Dreyer">[[John Louis Emil Dreyer]], ''Tycho Brahe: a Picture of Scientific Life and Work in the Sixteenth Century'', A. & C. Black (1890), pp. 162–3</ref>

Brahe, a Danish noble, was an essential astronomer in this period.<ref name="John Louis Emil Dreyer" /> He came on the astronomical scene with the publication of ''De nova stella'', in which he disproved conventional wisdom on the supernova [[SN 1572]]<ref name="John Louis Emil Dreyer" /> (As bright as Venus at its peak, SN 1572 later became invisible to the naked eye, disproving  the [[Aristotle|Aristotelian]] doctrine of the immutability of the heavens.)<ref>{{cite journal|last=Kollerstrom|first=N.|author-link=Nicholas Kollerstrom|date=October 2004|title=Galileo and the new star|url=https://www.dioi.org/kn/NewStar.pdf|journal=[[Astronomy Now]]|volume=18|issue=10|pages=58–59|bibcode=2004AsNow..18j..58K|issn=0951-9726|access-date=20 February 2017}}</ref><ref name=ruiz>{{cite journal|arxiv=astro-ph/0309009|bibcode=2004ApJ...612..357R|title=Tycho Brahe's Supernova: Light from Centuries Past|journal=The Astrophysical Journal|volume=612|pages=357–363|last1=Ruiz-Lapuente|first1=Pilar|year=2004|issue=1|doi=10.1086/422419|s2cid=15830343}}</ref> He also created the [[Tychonic system]], where the Sun and Moon and the stars revolve around the Earth, but the other five planets revolve around the Sun. This system blended the mathematical benefits of the Copernican system with the "physical benefits" of the Ptolemaic system.<ref name="Westman, Robert S 1975 p. 322">[[Patronage in astronomy#Robert Westman|Westman, Robert S.]] (1975). ''The Copernican achievement''. University of California Press. p. 322. {{ISBN|978-0-520-02877-7}}. [[OCLC]] 164221945.</ref> This was one of the systems people believed in when they did not accept heliocentrism, but could no longer accept the Ptolemaic system.<ref name="Westman, Robert S 1975 p. 322"/> He is most known for his highly accurate observations of the stars and the planets. Later he moved to Prague and continued his work. In Prague he was at work on the [[Rudolphine Tables]], that were not finished until after his death.<ref name="Athreya">Athreya, A.; Gingerich, O. (December 1996). "An Analysis of Kepler's Rudolphine Tables and Implications for the Reception of His Physical Astronomy". ''Bulletin of the American Astronomical Society''. '''28''' (4): 1305.</ref> The Rudolphine Tables was a star map designed to be more accurate than either the [[Alfonsine tables]], made in the 1300s, and the [[Prutenic Tables]], which were inaccurate.<ref name="Athreya" /> He was assisted at this time by his assistant Johannes Kepler, who would later use his observations to finish Brahe's works and for his theories as well.<ref name="Athreya" />

After the death of Brahe, Kepler was deemed his successor and was given the job of completing Brahe's uncompleted works, like the Rudolphine Tables.<ref name="Athreya" /> He completed the Rudolphine Tables in 1624, although it was not published for several years.<ref name="Athreya" /> Like many other figures of this era, he was subject to religious and political troubles, like the [[Thirty Years' War]], which led to chaos that almost destroyed some of his works. Kepler was, however, the first to attempt to derive mathematical predictions of celestial motions from assumed physical causes. He discovered the three [[Kepler's laws of planetary motion]] that now carry his name, those laws being as follows:

# The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit.<ref>{{cite book |last=Stephenson |first=Bruce |date=1994 |title=Kepler's Physical Astronomy |publisher=[[Princeton University Press]] |isbn=0-691-03652-7}}{{rp|p=170}}</ref>

[[Image:galileo.arp.300pix.jpg|thumb|[[Galileo Galilei]] (1564–1642) crafted his own telescope and discovered that the Moon had craters, that Jupiter had moons, that the Sun had spots, and that Venus had phases like the Moon. Portrait by [[Justus Sustermans]].]] The invention of the [[telescope]] in 1608 revolutionized the study of astronomy. [[Galileo Galilei]] was among the first to use a telescope<ref>{{cite web | title=The Galileo Project &#124; Science &#124; Telescope | url=http://galileo.rice.edu/sci/instruments/telescope.html }}</ref> to observe the sky, after constructing a 20x refractor telescope.<ref>GINGERICH, O. (2011). Galileo, the Impact of the Telescope, and the Birth of Modern Astronomy. ''Proceedings of the American Philosophical Society,'' ''155'' (2), 134–141.</ref> He discovered the four largest moons of Jupiter in 1610, which are now collectively known as the [[Galilean moons]], in his honor.<ref name="Satellites of Jupiter">"Satellites of Jupiter". ''The Galileo Project''. [[Rice University]]. 1995.</ref> This discovery was the first known observation of satellites orbiting another planet.<ref name="Satellites of Jupiter" /> He also found that the Moon had craters and observed, and correctly explained sunspots, and that Venus exhibited a full set of phases resembling lunar phases.<ref name="Stanford Solar Center">{{cite web|url=http://solar-center.stanford.edu/gal-challenge/gquiz6c.htm|title=How did Galileo prove the Earth was not the center of the solar system?|access-date=13 April 2021|publisher=Stanford Solar Center}}{{Dead link|date=August 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> Galileo argued that these facts demonstrated incompatibility with the Ptolemaic model, which could not explain the phenomenon and would even contradict it.<ref name="Stanford Solar Center" /> With Jupiter's moons, he demonstrated that the Earth does not have to have everything orbiting it and that other bodies could orbit another planet, such as the Earth orbiting the Sun.<ref name="Satellites of Jupiter" /> In the Ptolemaic system the celestial bodies were supposed to be perfect so such objects should not have craters or sunspots.<ref>Lawson, Russell M. (2004). ''Science in the Ancient World: An Encyclopedia''. [[ABC-CLIO]]. pp. 29–30. {{ISBN|1851095349}}.</ref> The phases of Venus could only happen in the event that Venus orbits around the Sun, which did not happen in the Ptolemaic system. He, as the most famous example, had to face challenges from church officials, more specifically the [[Roman Inquisition]].<ref name="Finnocchiaro">Finnocchiaro, Maurice (1989). ''The Galileo Affair''. Berkeley and Los Angeles, California: University of California Press. p. 291.</ref> They accused him of heresy because these beliefs went against the teachings of the Roman Catholic Church and were challenging the Catholic church's authority when it was at its weakest.<ref name="Finnocchiaro" /> While he was able to avoid punishment for a little while he was eventually tried and pled guilty to heresy in 1633.<ref name="Finnocchiaro" /> Although this came at some expense, his book was banned, and he was put under house arrest until he died in 1642.<ref>{{cite book|title=Parallax: The Race to Measure the Cosmos|last=Hirschfeld|first=Alan|date=2001|publisher=Henry Holt|isbn=978-0-8050-7133-7|location=New York, New York}}</ref>[[Image:Table of Astronomy, Cyclopaedia, Volume 1, p 164.jpg|thumb|left|Plate with figures illustrating articles on astronomy, from the 1728 ''[[Cyclopædia, or an Universal Dictionary of Arts and Sciences|Cyclopædia]]'']] [[Sir Isaac Newton]] developed further ties between physics and astronomy through his [[Newton's law of universal gravitation|law of universal gravitation]]. Realizing that the same force that attracts objects to the surface of the Earth held the Moon in orbit around the Earth, Newton was able to explain – in one theoretical framework – all known gravitational phenomena. In his ''[[Philosophiæ Naturalis Principia Mathematica]]'', he derived Kepler's laws from first principles. Those first principles are as follows:

[[Edmond Halley]] succeeded [[John Flamsteed]] as [[Astronomer Royal]] in England and succeeded in predicting the return of the [[Halley's Comet|comet that bears his name]] in 1758. [[William Herschel]] found the first new planet, [[Uranus]], to be observed in modern times in 1781.{{Sfn|Hoskin|2011}}

At first, [[Colonial American Astronomy|astronomical thought in America]] was based on [[Aristotelian philosophy]],<ref>{{Citation|last=Brasch|first=Frederick|author-link=Frederick Edward Brasch|title=The Royal Society of London and its Influence upon Scientific Thought in the American Colonies|journal=The Scientific Monthly|date=October 1931|volume=33|issue=4|pages=338|postscript=.}}</ref> but interest in the new astronomy began to appear in [[Almanacs]] as early as 1659.<ref>{{Citation|last=Morison|first=Samuel Eliot|title=The Harvard School of Astronomy in the Seventeenth Century|journal=The New England Quarterly|date=March 1934|volume=7|issue=1|pages=3–24|postscript=.|doi=10.2307/359264|jstor=359264}}</ref> The gap between the planets Mars and Jupiter disclosed by the [[Titius–Bode law]] was filled by the discovery of the [[asteroid]]s [[Ceres (dwarf planet)|Ceres]] and [[2 Pallas|Pallas]] in 1801 and 1802 with many more following.

Ideas in this direction were expressed in antiquity, by [[Anaxagoras]] and  by [[Aristarchus of Samos]], but did not find mainstream acceptance. The first astronomer of the European Renaissance to suggest that the stars were distant suns was [[Giordano Bruno]] in his ''De l'infinito universo et mondi'' (1584). This idea was among the charges brought against him by the Inquisition. Telescopic observations by [[Galileo Galilei]] showed that the [[Milky Way]] was a great concentration of individual stars.<ref name=Sanders-2013>{{Citation |title=The Discovery of the Milky Way Galaxy |date=2013 |work=Revealing the Heart of the Galaxy: The Milky Way and its Black Hole |pages=13–24 |editor-last=Sanders |editor-first=Robert H. |access-date=2026-04-29 |place=Cambridge |publisher=Cambridge University Press |doi=10.1017/CBO9781139856546.002 |isbn=978-1-107-03918-6}}</ref> The idea of many stars became mainstream in the later 17th century, especially following the publication of ''[[Conversations on the Plurality of Worlds]]'' by [[Bernard Le Bovier de Fontenelle]] (1686), and by the early 18th century it was the default working assumptions in stellar astronomy.

[[Image:Mars Schiaparelli MKL Bd. 11 1890 (128500338).jpg|thumb|[[Mars]] surface map of [[Giovanni Schiaparelli]]]]

The Sun was found to be part of a [[galaxy]] made up of more than 10¹⁰ stars (10 billion stars). The existence of other galaxies, one of the matters of ''[[the great debate]]'', was settled by [[Edwin Hubble]], who identified the [[Andromeda Galaxy|Andromeda Nebula]] as a different galaxy, and many others at large distances and receding, moving away from our galaxy.

* {{cite book |last=Hoskin |first=Michael |year=2003 | author-link = Michael Hoskin |title=The History of Astronomy: A Very Short Introduction |publisher=Oxford University Press |isbn=0-19-280306-9 |ref=none}}

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