History of astronomy

The history of astronomy includes time the entire history of human civilization. The astronomy was transformed from mere observation of the night sky and its cycles of the classical geometrical astronomy, the oldest part of application are the position and ephemeris astronomy, to modern astrophysics.

The star customer determines the image of himself and his conception of his position in the universe today. Mainly by the discussions on the origin of the universe and the search for habitable planets and life beyond our solar system

• 2.2.1 Alternatives to the geocentric

• 3.1 India
• 3.2 Melanesia
• 3.3 China
• 3.4 America

• 4.1 Western Europe
• 4.2 Islamic astronomy 4.2.1 Cultural Exchange with Islam

• 6.1 The 17th century 6.1.1 Calculation of the speed of light

• 6.2.1 The prediction of a comet
• 6.2.2 Star clusters and nebulae
• 6.2.3 " Everything is in motion " ( Panta Rhei )
• 6.2.4 The discovery of Uranus

• 7.1 The discovery of Neptune

• 8.1 1900-1930
• 8.2 mid-20th century
• 8.3 The 1970s
• 8.4 space - probes
• 8.5 The 1980s and 1990s
• 8.6 planets in other solar systems
• 8.7 Conclusion of the 20th century

Prehistoric sky observations

For prehistoric sky observations including murals are just a few clues before, in the cave of Lascaux ( approximately 17000-15000 BC), in which perhaps the Pleiades and the zodiac are illustrated, and a found in France, the Abri Blanchard wing bone of an eagle with dot markers, whose number and arrangement may be related to the phases of the moon. However, the lack of relevant archaeological find material does not prove that the observation of the sky generally played no role in the prehistoric humanity. In any case, in today's hunter- gatherer cultures, such as the Aborigines, such a well attested.

In the Neolithic period, the source situation changes markedly. The use of a calendar, which presuppose a certain knowledge about the events in the sky, has been vital for agricultural crops. An advance knowledge of important annual events allowed planning. This religious interpretations of celestial phenomena and their possible causes were connected.

It is conceivable that the transition to farming for the formation of various astral cults and to the beginnings of astronomy and also to the emergence of astrology (both Western and Asian ) has contributed. Numerous tombs of this period were oriented to a certain direction. Among the archaeological finds that are related to calendars, including those found in southern Germany and France gold hats, which are interpreted as religious headgear by priests of a sun cult and the Sky Disc of Nebra. Built about 7000 years ago circle grave system of Goseck is referred to as the oldest solar observatory in the world. The most impressive prehistoric cultural site in Europe is Stonehenge. About practiced at Stonehenge cults nothing is recorded, but the geographical orientation of the building creates a close astronomical reference. The same can be world show for cult buildings from many eras.

By the Archaeoastronomy has been around since the 1970s, a private specialty that deals with the exploration of these buildings and discoveries under the astronomical point of view.

Astronomy in the early civilizations

The first lunar eclipse, the observation of which is supposedly narrated is that of 17 January 3380 BC, said to have been recorded by the Maya in Central America. This assumption is controversial because the research assumes that the Maya at the earliest after 3373 introduced their calendar BC. Partly allegations that he already began earlier, have not yet be proved. In China, the first solar eclipse was recorded in 2137 BC

The Egyptians and Mesopotamians watched the sky and worshiped astral deities. On June 6, 763 BC, the first datable observation of a solar eclipse falls in Mesopotamia.

Egyptian and Mesopotamian astronomy

The celestial event was also linked to the ancient civilizations of North Africa and the Middle East with mythology and religion.

Egypt

In contrast to Northern Europe, where you can draw in the study of prehistoric astronomy only on archaeological knowledge, exist for Egypt to the 3rd millennium BC, reaching back a written record of techniques and importance of the ancient Egyptian astronomy. The then- astronomical " research " and interpretations must also be understood in the context of prevailing in the then Egypt sun cult and the efforts to calculate the exact fulfillment of the Nile flood.

The Egyptians made ​​use of for the night twelve stars at the time of measurement, the length of the first and last period was adjusted depending on the season. The mythological background of the Twelve night star ( " star that never perish ") was the belief that the overnight crossing of the deceased king with the sun god Re, under the protection of the Twelve Guardians of the night sky took place. It began with the onset of dusk and ended with the sunrise. Constellations also played an important role. They contained the stars of various gods. The oldest representation of the night sky can be found on the bottom of a coffin in Assiut, another in the grave chamber of Senmut ( Thebener grave TT353 ). The representation of the constellations, which was then usual - so also in the King Seti I. grave to 1279 BC - is not consistent with the current classification of the constellations.

What methods used the Egyptian astronomers exactly is not known. In the Egyptian calendar Sirius played a special role because its heliacal rising from about 2000 BC, announced the inundation. Originally Sirius but seems to be associated with the beautiful Feast of the Valley. Since that time the Egyptian year was 365 days long, the date of the heliacal rising of Sirius changed slowly; he fell after a cycle from 1440 to 1460 years back on the same date of the Egyptian calendar. The history of the ancient Egyptian religion shows that the priests watch over their astronomical knowledge and even to 221 BC, a reform of the calendar with an improved year length of 365.25 days made ​​undone. This may be related to the fact that the priests were for the calculation of the religious holidays that are moved slowly in a 365 -day calendar, in charge; this task would have been lost them in a revised calendar of 365.25 days.

Mesopotamia

A central concern of Mesopotamian astronomy was astrological predictions and the study of celestial omens. Babylonians and Assyrians preserved in their archives records of their astronomical observations that go back even on conservative estimates to the third millennium BC.

The Sumerians created by the astronomical constellations of their calendar. Thousands of traditional clay tablets in cuneiform astronomical texts contain that are assigned especially the archives of Uruk and Nineveh. Early in the 3rd millennium BC, the Venus was described as star of Inanna. Ancient cylinder seal and texts to Inanna as the embodiment of the planet Venus prove the age of the Sumerian knowledge: Inanna, Venus as you see all foreign countries are lit. I want to offer her as mistress of heaven, a song.

Based on a long series of observations Babylonian astronomers developed mathematical series, which enabled the calculation of the positions of celestial bodies and the prediction of celestial phenomena. As early as 1000 BC they were able to isolate complex superpositions of periodic phenomena in the individual periods and calculate so.

Nabu - rimanni was the earliest known by name Babylonian- Chaldean astronomer.

Calendar System | computing system ACT Texts | Astronomical observation Texts | astrolabe B | Enuma Anu Enlil | Gadex texts | Kidinnu | Nabu - rimanni | Nibiru | Venus tablets of Ammi - saduqa

Knowledge tradition to the Greeks

Simple forms of the armillary sphere have been used among the Babylonians and later further developed by the Greeks. The division of the zodiac into 360 degrees, which probably goes back to the Egyptian decans were also taken as individual observations and the planet names and periods of the Babylonians. Not taken but were the underlying mathematical methods; the Greek approach was different, since the Greek philosophers the universe primarily geometric, not arithmetic understood.

Today's knowledge about the beginnings of Greek astronomy and the extent of their influence from the Mesopotamian is very patchy. It is assumed that the loss of books in late antiquity also applied to numerous astronomical works.

The Greek philosophers and astronomers

Notes on the employment of the ancient Greeks with the events in the sky have been very early literary texts. Both Homer and Hesiod mention astronomical conditions; the zodiac is attested in Homer only partially. These two authors still show no deeper understanding; they describe morning and evening star as different objects. At the latest at the time of Plato this mistake was corrected thanks Babylonian information; This progress was later attributed to Pythagoras.

The pre-Socratics developed to the 5th century BC different astronomical models. They invented, among other increasingly accurate methods of measuring time, about sundials, whose foundations they probably took over from the Babylonians. Anaximander, a contemporary and pupil of Thales, postulated the geocentric world view by first described the sky as a spherical shell ( sphere ) with the Earth in the center. Earlier cultures saw the sky as a hemisphere just above the flat earth, without touching the outside of myths problem where the stars between up-and- doom befänden. However, the transition to the earth as a sphere made ​​not Anaximander.

The Greek culture of the classical period operation for the first time astronomy of scientific interest in the actual operations in the sky, regardless of the practical use of the calendar, as well as of religious and astrological motifs. Today is famous remarkably precise measurement of the Earth's circumference by Eratosthenes around 220 BC, the, in different latitudes attributed the lengths varying shades of the sun on the same day in Alexandria and Syene, where it is at its zenith exactly on a ball. Less well known is the attempt of Aristarchus of Samos, to measure the distance to the sun in relation to the Moon distance due to insufficient measurement accuracy very buggy turned out ( he was by a factor of 20 destined to shortly ), but was methodologically correct.

Hipparchus of Nicaea and others developed the astronomical instruments that almost two thousand years later remained until the invention of the telescope in use, such as an angle measuring instrument, a kind of refined armillary sphere, could be determined with the coordinates on the celestial sphere. It was introduced by Eratosthenes still under the name astrolabe and also described by Ptolemy. One of the few remaining technical objects from the Greek period is the Antikythera mechanism, the earliest known gear apparatus (ca. 100 BC). The mechanism is interpreted as an analog computer for prediction of celestial bodies movement, which was designed by perhaps Posidonius ( 135-51 BC).

Another essential groundwork for the astronomy of later times made ​​Aristotle ( 384-322 BC) recognized the principle of the camera obscura.

The work of Ptolemy around 150 AD represented the culmination and completion of ancient astronomy dar. Ptolemy developed on the basis of already in his time of existing works ( Hipparchus and other ) named after him worldview and gave the Almagest a standard work of Astronomy out on the star catalog, astronomers relied until the Renaissance addition. The Romans valued astronomy as part of education, but not extended it. She was interested in astrology rather than a way to look into the future. A part of the ancient literature was preserved in the Eastern Roman Empire, but the cultural exchange with the Latin -speaking scholarly world of Western and Central Europe came at the beginning of the early Middle Ages to a virtual standstill.

Alternatives to the geocentric

Repeats alternatives have been proposed heliocentric worldview. Some Pythagoreans thought that the center of the universe, a central fire, which would orbits of the Earth, the Sun and the planets located. Aristarchus of Samos proposed in the 3rd century BC even before a heliocentric world view with the sun as stationary center. He also argued - as in the 4th century Heraclides Ponticus - for a daily axial rotation of the earth with immovable sky. The geocentric view with an immobile earth, around which revolve all spheres of daily, but remained until Nicolaus Copernicus who continued Aristarchus, the generally accepted model. The heliocentric draft of Copernicus was an alternative appear to be feasible, which was plausible by Johannes Kepler by the knowledge of the elliptical shape of planetary orbits.

Cornerstones of the development in antiquity

As insights and achievements of the ancient astronomers noted:

• The ability to calculate and predict the movements of the planets and the occurrence of eclipses ( Saros Cycle )
• The realization that the earth is spherical ( Aristotle, 384-322 BC: first guesses a circular earth due to earth's shadow in circular lunar eclipses; around 200 BC by Eratosthenes of Alexandria: from the first approximately correct calculation of the circumference of the earth over angle shadow at various locations )
• Proposing alternatives to the geocentric
• The created by 150 BC by Hipparchus of Nicaea and Archimedes first star catalogs (1000 stars)
• The discovery of the precession of the Earth This discovery is attributed to Hipparchus ( about 150 BC). Since then, that is the permanent change of the coordinates of the fixed stars in the night sky, and thus the equatorial coordinates of right ascension and declination is known.

Pliny the Elder, who wrote in AD 60 is an overall view of the former natural history knowledge, also treated astronomy as astronomy, in contrast to astrology.

Development of astronomy in India, China and America

In South - East Asia and the system of the present celestial coordinates was developed early. However, while in China the astronomical observations were performed rather than chronicle, you joined them in India as early as 1000 BC with a profound cosmology. In contrast, little is known about the astronomical background of the American civilizations relatively little.

India

In the Indus Valley Civilization, a detailed cosmology with the divine forces of nature heaven, earth, the sun emerged from 1000 BC (which was interpreted as a glowing stone), moon, fire, and the eight points of the compass. The world comes from a sacred egg of silver ( Proto-Earth ) and gold ( starry sky ) with the envelope of air as an intermediate layer. The sun was seen as divine eye of the universe, the moon cycle as a time and giver of life. The orbits of the planets pass between the sun and the North Star.

The traditional Vedic astronomy is strongly encrypted in verse, which makes their integration into a larger framework difficult. In general, it is very similar to the Babylonian what - can mean conversely Babylonian idols of Vedic astronomy and - depending on interpretation and dating. Both positions are discussed in the history of astronomy, but is also an essentially independent development possible. Because some of the similarities, such as the division of the zodiac into 360 degrees with twelve constellations can also be derived directly from nature. The year is rounded to 360 days, but the months are counted as today. However, follow the system of ancient Indian astronomy to two years of 360 days, more of a 378 days. The day has seasonally varying lengths ( " Muhurtas " with 9.6 to 14.4 hours).

An amazing correspondence to Christianity or to Teilhard de Chardin is worth mentioning: God is a loving spirit the world whose son up the evolution of the universe in mind. A second boost through the Indian astronomy around 500 AD by the astronomer Aryabhata, among others, the concept of number "null" is attributed. The five observatories are known Jai Singh II was built in the early 18th century, among others in Delhi and Jaipur. The largest of these, the Jantar Mantar in Jaipur, consists of fourteen buildings for observation and measurement of astronomical phenomena.

Melanesia

Here it should be mentioned especially the sophisticated navigation with sun and stars, which was a prerequisite for colonization of the island world. Narrated orientation methods are

• With the Polar Star and the Southern Cross, as well as
• Near horizon for East and West courses Peilsterne as in Adler, the direction of which changes only slightly because of the almost vertical stellar orbits.

The primordial night of the creation story does have stars, but even without the sun and moon. The divine separation of heaven and earth was a cult rod, similar to Orthodox icons. The abode of God and the unborn child is in the Milky Way, and the souls are the original form of the constellations.

China

An essential element of Chinese philosophy is the harmony of heaven, man and earth. Celestial phenomena were therefore judged in this light. The ambition of the Chinese, it was - according to the interpretation in the current literature of the People's Republic of China - Disturbances of this harmony to predict and thus to end the age of faith in incalculable heteronomy.

Therefore, the astronomers had to worry not only about the calendar in Imperial China, but also to the prediction of extraordinary celestial phenomena (eg eclipse ) and also to state astrology. They knew already about 2000 BC the Lunisolarjahr with a 19 -year-old switch usually because of the moon's nodes (see also Saros cycle). There was a scientific office, whose origins are no longer can be identified, but can be traced back to well before the birth of Christ. This office existed until 1911 with four main staff: The chief astronomer ( Fenxiangshi ), responsible for the uninterrupted sky show, the Chefastrologe ( Baozhangshi ), which were subject to the records, the chief meteorologist ( Shijinshi ) for weather phenomena and solar eclipses, and the keeper of time ( Qiehushi ), who was in the calendar calculations.

This ancient Chinese chronicles are still regarded as a reliable and relatively complete - also because the officials vouched for their results with their lives. It is reported that the astronomers Xi and He were beheaded for the failed prediction of the solar eclipse of October 3, 2137 BC. From the turn of time were observed, inter alia, sunspots, which is possible during sunrise and sunset with the naked eye, as well as novae and supernovae, the guest stars are called, or already 613 BC, the comet Halley.

According to the worldview of imperial China, there are five areas of the sky, the four cardinal directions and the center, including the circumpolar region and represents the imperial palace. There are instruments similar to the armillary sphere used, but it is unclear whether they result from contacts with the Greek and Islamic world or complete in-house developments. Furthermore, Chinese zodiac cards are handed to maritime navigation. Missionaries carried from 1600, the findings of modern European astronomy to China. For example, the imperial observatory was conducted in the Qing dynasty traditionally by the Jesuits as Ignaz Anton Koegler or Gogeisl.

Intensive research of Chinese history of astronomy, the results he published in several representations, operational science historian Yabuuchi Kiyoshi.

America

Little is known about the astronomical world view of the indigenous civilizations, but give religious buildings (eg steps temple with a precise orientation) and Observatories numerous references. Most fonts and codices were destroyed by the conquistadors. But the calendar calculations and the calculation of planetary cycles was Undoubtedly sophisticated - see the Maya and the Aztec calendar. 1479 created the Aztecs the " sun stone ".

The orbital periods of the five freisichtigen planets were partially known to only a few minutes. The duration of the month agreed to six decimal places with today's values ​​- which is not even 1 hours constitutes error per century.

Astronomy in the Middle Ages

From the Middle Ages two particularly striking celestial phenomena have survived: 1054 AD was observed world a new star in the constellation Taurus ( "Supernova 1054 " ), which remained for weeks also visible during the day ( in the M1 Crab Nebula ), and on June 25, 1178 observed the monk and chronicler Gervase of Canterbury, a luminous phenomenon on the crescent moon, which is could have been a meteor impact ( formation of the crater Giordano Bruno? ).

Western Europe

In the Middle Ages, the ancient astronomical literature remained in the Greek-speaking Byzantine Empire still accessible and has been studied. In the Latin -speaking West, however, was to the 12th century, very little of the ancient Wissensgut available. There they remained true to the teaching repertoire of the Seven Liberal Arts in in which was the Astronomy one of the four parts of the quadrivium, but in practice only the Trivium was at the convent schools of the early Middle Ages usually taught, which included no scientific substance.

As part of the reform policy of Charlemagne astronomy was upgraded as a subject: The Emperor undertook all cathedrals for the construction of schools in which astronomy in addition to the other subjects of the quadrivium ( geometry, arithmetic and music) should be taught; it was also about the important for the Clergy ability to calculate the date of Easter. However, these reforms resulted in little, and astronomy knowledge remained poor in practice.

In the Carolingian period, however, emerged copies of astronomical didactic poems of Aratus, such as the beautifully illustrated Leiden Aratea that were probably given by the court of Louis the Pious in order. Together with Aratus were the constellation descriptions of Hyginus in Poeticon Astronomicon until the end of the late Middle Ages widespread standard works. The knowledge of classical constellation myths originated mainly from these two works. The illustrations are artistic quality. The positions at which the illustrators put the stars, however, have little to nothing in common with the actual firmament; Rather, they have been chosen so that they fit well to the figures.

The few other preserved ancient works on astronomy were first written down only in the monasteries, also increasingly commented to the incipient scholasticism in the 11th century. You must confirm by their own observations to supplement or refute, but not up to the medieval understanding of science. Astronomy was therefore understood at that time as an at least substantially completed science to the understanding of one's own observation of the night sky was not necessary. The sudden appearance of a supernova in 1054 was one of the first events that brought the widely prevalent, static understanding of the cosmos to falter.

In the late Middle Ages began a stronger interest in astronomy. By the early letterpress and astronomical works were disseminated. In addition to copies of the above-mentioned two ancient works were, for example, the German astronomer Regiomontanus numerous astronomical books out, including a calendarium, which can be considered as a bestseller by former standards. In 1472 he succeeded in the initial measurement of the angular diameter of a comet. Regiomontanus was empirically set and ready to challenge traditional ideas. Personal observation and comparison with the results of ancient science should renew and help astronomy, in his view, to find "the truth". With this attitude he was next to Nicholas of Cusa, the essential precursor of the Copernican worldview. About Regiomontanus and others acting in Vienna astronomer and mathematician Georg Tannstetter wrote his account of Viri Mathematici (1514; German: Mathematical men ), an early approach to the historiography of science.

The monk Roger Bacon built on the model of Aristotle for solar observations, the first apparatus in the form of a camera obscura, and described in 1267 the construction of a lens correctly.

Islamic Astronomy

After astronomy still taught in the Roman Empire, but not expanded, a progress was again only with the Islamic expansion. The leading scientists were often court astronomer or court mathematician. The Arab services primarily related to astrometry: Precise observations of the sky were carried out - especially for astrological purposes, although Islam is the attempted look into the future reluctantly saw and astrology actually not allowed - and created star catalogs, which add substantially to the usual today star names contributed. Even instruments such as the astrolabe were further developed.

However, without telescopes, the Islamic astronomers were not significant enhancements of the ancient knowledge in the situation. The geocentric view was generally accepted only its details, such as epicycles or spheres were first discussed, corrected and expanded. Because of the interval since the stoppage time of these theories, in which the error had accumulated, the discrepancies of the ancient theories with the observations for the Islamic scholars were evident. In the 16th century, when completed the Copernican revolution in Europe, Islamic scholars rejected the ancient worldviews increasingly from. The extent to which these two pathways were independent, or whether Copernicus had detours knowledge of Islamic developments, is not known.

Many advances of the Islamic astronomers were ultimately consequences, such as the Ulugh Beg built from the early 15th century observatory of Samarkand. As the best of his time successors it was after only one generation of Ulugh Beg's looped and left to decay. Other Islamic observatories suffered a similar fate, only 1264 built by Nasir al- Din al - Tusi Observatory of Maragha survived its builder by as much as nearly forty years before it was closed 1304-1316. Although the Islamic astronomers detected the errors of the ancient theories and they improved, was their most important from today's perspective performance yet in the store, translate and partially expand the ancient natural science, to which European culture during the Early Middle Ages was hardly able. With the end of the heyday of Islam in the 15th century could the Islamic astronomy of Europe but barely to give impulses and their services were eventually overtaken by the European Renaissance and fell into oblivion.

The level of development of Islamic astronomy is also exemplary of the Astronomy of other cultures, which reached a similar level, but ( also without telescopes ) could not develop beyond. Particularly noteworthy are the Indian or Vedic astronomy, the Chinese and pre-Columbian Astronomy of the Indian civilizations. All of these cultures had an accumulated over many centuries beobachterisches knowledge, with which the periodic phenomena of the solar system could be predicted.

Cultural exchange with Islam

Through cultural exchanges with the Islamic countries, especially after the establishment of the Crusader states in the Middle East in the 12th century and during the Reconquista ( School of Translators of Toledo), reached the works of Aristotle and Ptolemy via the intermediate step of Arabic translation back to the west. Only Byzantine emigres finally brought the ancient art after the conquest of Constantinople by the Ottomans in the original, or in Greek copy, to Central Europe. In the High Middle Ages were philosophical and theological considerations of the universe rather than the focus concretely observed celestial events. The different models of the celestial spheres, as described for example in the rediscovered works of Aristotle and Ptolemy were extensively discussed and example questions on the number of spheres, or whether the sphere of fixed stars even turn on the day or the earth. On the principles of this cosmology, however, no doubt.

Astronomy in the Renaissance

The age of the Renaissance marked the flowering of classical astronomy as a science of the geometrical structure of the universe, a science which he devoted himself only just beginning the study of the physical background of the star movement. Astrology and astronomy were to the Renaissance into not contradictory, but not, as sometimes claimed, identical. Many astronomers started until well into the 17th century also horoscopes for their clients, but saw it as not their main activity. The classical astronomy is concerned only with the positions of stars and planets as well as their exact calculation, astrology tried these positions with regard to the earthly events to interpret. So Astronomical knowledge was the basis for astrology.

The European astronomy was given a new orientation by the work of Nicolaus Copernicus. According to observations of the moon against the backdrop of the fixed stars he doubted the geocentric and worked out a model in which the sun is at the center of the cosmos. In 1543 he put it in his book De revolutionibus before orbium Coelestium.

1519-1522 managed by the Fernão de Magalhães ( Magellan ) led the expedition Erstumsegelung the earth, while also discovering the Strait of Magellan, the Philippines and the rediscovery of the Magellanic Clouds in the southern sky (as well as the International Date Line ). A new era of astronomy led a Nicolaus Copernicus. He laid in May 1543 his book De revolutionibus orbium Coelestium mathematically demonstrate that the planetary motions can be correctly described with a heliocentric worldview. Daniele Barbaro in 1568 improved the camera obscura through the use of a lens, thus making essential groundwork for the astronomers of later generations. Tycho Brahe surveyed for the first time the orbits of comets and drew conclusions from their distance (1577 ) - the big "astronomical " distances were palpable. Previously observed Tycho supernova ( 1572) as well as the orbit of Mars, and after 1603 Johann Bayer had published the first modern star catalog ( Uranometria ), described in 1609 Johannes Kepler in his book Astronomia Nova was named after him first and second Kepler law of planetary motions around the sun (his previously published works were pioneers of his Astronomia Nova ). Now, a correct description of planetary motion was present from heliocentric view. The necessary preparatory work had done with his self-developed mural quadrant of Tycho Brahe. This instrument replaced the customary since ancient armillary sphere from a universal instrument. The accuracy of Brahe's position measurements of the planet allowed Johannes Kepler until the discovery of the laws of planetary motion.

The invention of the telescope in the early 17th century sealed the era of astronomy. Galileo Galilei discovered with the aid of the four inner moons of Jupiter and the phases of Venus. These findings were published in part in 1610 in Sidereus Nuncius. Thus, the Ptolemaic world view has been significantly weakened. It became clear that the Copernican system was like the geocentric model with the observations of Brahe tolerated. A crucial evidence was neither theoretically nor practically possible at this time. Although the subsequent dispute with the church ended with the legal victory of the Inquisition against Galileo, but established a problematic relationship between the Church and science.

Astronomy in the Age of Reason

European rulers encouraged the Astronomy increasingly at their courts as a sign of culture and education, to give a human and a financial boom of the research showed. In addition Nationalobservatorien were founded, such as the Royal Greenwich Observatory or the Paris Observatory. Their mission was to deliver especially tables for navigation and to solve the length problem, but next they operated astronomical research. During the research of the court astronomer was tied to the personal interest of princes, could develop to the Nationalobservatorien longer-term research traditions so that such independent observatories at the latest at the beginning of the 19th century took a leadership role in research.

The 17th century

At the beginning of the 17th century astronomers began to observe celestial bodies with the help of newly discovered optical instruments. The first functional telescope was built about 1608 in the Netherlands. Who was the actual inventor is disputed.

1609 Johannes Kepler published Astronomia Nova his work with the first two kepler 's laws. The astronomer Simon Marius discovered in 1612 our neighboring galaxy, the Andromeda Galaxy, through the telescope again ( it had been first discovered by the Persian astronomer Al- Sufi in the 10th century). Already in 1610 published Sidereus Nuncius Galileo Galilei his book, in which he reported on his recent discoveries by telescope. 1632 his "Dialogue on the Two Chief World Systems " was released, but he had on June 22, 1633 abjure the heliocentric world view. He died on 8 January 1642. Johann Baptist Cysat discovered 1619 new, physically belong together double star systems. This led to speculation about planetary systems around other stars, a possibility which was previously only philosophically, from Giordano Bruno discussed.

Giovanni Riccioli in 1651 published the first map of the moon; 1655/56 succeeded Christiaan Huygens and Giovanni Domenico Cassini discovery of the rings of Saturn, the moon Titan and the Orion Nebula ( Huygens, published in 1659 in Systema Saturnium ). Huygens was the first to the true nature of the rings of Saturn.

1668 Isaac Newton came up with the idea to combine the light with mirrors instead of lenses made of glass - the invention of the reflecting telescope. Also he succeeded in 1669 the discovery of the mass attraction ( gravity ) and the first theory to explain the phenomenon " light " as a particle, so that the understanding of the cosmos was slowly placed on a new basis. He laid with the 1687 published epochal work Philosophiae Naturalis Principia Mathematica, the first foundations of astrophysics by he attributed the kepler 's laws on his theory of gravitation.

During this time, Cassini discovered in 1671, Saturn's moons Iapetus, Rhea 1672, Tethys and Dione 1684. From 1683 to 1686 found and declared Cassini and Nicolas Fatio de Duillier the zodiacal light.

Calculation of the speed of light

1676 proved Ole Rømer delay on the Jupitermondverfinsterungen depending on their Erdabstand that the speed of light is finite. After his decisive preliminary work, it was the first time in 1678 by Christiaan Huygens with about 213,000 km / s calculated (today's value is c = 299,792.458 km / s ) by the run- time specification (22 min = 1320 s ) of the Romans and the Earth's orbit diameter ( 280 million km in today's units, the true value is 299 million km ) used by Cassini ( published in treatise on light, 1690).

The 18th century

The prediction of a comet

Newton concluded in his Principia, that comet is similar to the planet, but move in elongated ellipses around the sun ( " Diximus Cometas eat genus Planetarum in Orbibus valde excentricis circa Solem revolventium "). By comparing the traditional Kometensichtungen to recurring objects would show. Edmond Halley took over this task and published in 1705 his calculations. He postulated that the comet must be identical with previous appearances in the years 1607 and 1531 of 1682, and deduced his return for 1758/59 from. The arrival of this prediction was a great triumph of the Newtonian theory, but also unique. Many comets have been predicted at this time, even two more of Halley. Only in 1822 was a small (only visible through a telescope ) comet as periodically confirmed ( 2P/Encke ). The fact that a farmer from Saxony ( Palitzsch ) and not professional astronomers in Paris or London discovered the 1P/Halley, was a result of the popularization of modern science and situation also provided a sensation.

Star clusters and nebulae

With increasingly powerful telescopes exploring the foggy sky objects has been an important area of ​​work. The brighter star clusters have been recognized as such. In low fog and gas clouds, the method of indirect vision has been applied.

Charles Messier created in 1774 the first systematic list of the " fog objects", the Messier catalog used today. However, the main purpose was the distinction between comets.

" Everything is in motion " ( Panta Rhei )

1718 Halley presented by comparison with ancient star maps the thesis of the proper motion of the fixed stars on.

1728 James Bradley discovered in a vain attempt to measure a parallax of the " fixed stars " that the position of each star in the course of the year varies ( aberration). This was also recognized by most of the time still many supporters of Tycho's worldview as evidence of the movement of the earth. Moreover, it was so light and movement confirmed the speed of light can be calculated more accurately.

1755 designed Immanuel Kant first theories of a purely resulting from mechanical processes formation of our solar system.

1761 is recognized by several observers of the transit of Venus on June 6, the first extraterrestrial atmosphere.

1769 James Cook participated in Tahiti as one of several distributed on Earth observers of the transit of Venus on 3 June at for well over a century the most accurate determination of distance Earth - Sun.

The discovery of Uranus

The planet Uranus was, even though it is visible to the naked eye, under favorable circumstances, has not been recognized by the ancient astronomers as a planet. After the invention of the telescope, he was first sighted by John Flamsteed on December 23, 1690 was " 34 Tauri " cataloged as a star. March 13, 1781 William Herschel held " 34 Tauri " initially for a comet. The idea that there could be another planet, Nevil Maskelyne comes from. 1787 Herschel discovered Titania and Oberon, the moons of Uranus and 1783, the self-movement of the sun towards the constellation Hercules and Lyra. This was our sun finally one of many stars that move in our Milky Way, and the level of knowledge about the objects of the sky had been extended.

The 19th century

In this era, the knowledge of the fundamental physics of astronomical phenomena observed sky, the light developed. 1800 William Herschel discovered infrared radiation in 1802 William Hyde Wollaston the absorption lines in the spectrum of sunlight. Regardless of Wollaston described Joseph von Fraunhofer in 1813 named after him Fraunhofer lines in the solar spectrum and a year later invented the spectroscope. Through the research of Gustav Robert Kirchhoff and Robert Wilhelm Bunsen made ​​it possible in 1859 to explain the absorption lines in the solar spectrum and thus to lay one of the essential foundations for modern astronomy; astrophysics emerged. The celestial objects were classified by spectral analysis in classes that could be traced later on physical similarities. 1890 started a group astronomers, among them Williamina Fleming, Antonia Maury and Annie Jump Cannon, the classification of the stars according to their spectra ( spectral class ) to work out.

Another major step was the addition of the human eye as the observation instrument through photography. The first fade-resistant image was taken in 1826 by Joseph Nicéphore Nièpce. John William Draper in 1840 took the first photo of the moon on using daguerreotype. Thus, not only the observations in the subsequent years of objective, hour-long exposures were also opened the possibility of fainter objects to explore much more detailed. One of the first astronomers who used them, was the Jesuit Angelo Secchi, director of the Vatican Observatory; He is also regarded as the pioneer of spectral analysis.

Alvan Graham Clark found in 1862 by Friedrich Wilhelm Bessel in 1844 predicted companion star of the Dog-star on ( Sirius B), which later turned out as a dwarf star of extremely high density. 1877 was Asaph Hall, the two moons of Mars Schiaparelli and the apparent " canals of Mars " - in the sequence were speculations about " Martians " new impetus. Gustav Witt in 1898 reported the discovery of the asteroid Eros.

The discovery of Neptune

Inspired by the success of Herschel in the discovery of Uranus, astronomers were searching the other planets and were successful with the objects of the asteroid belt. Since Uranus had been a century earlier cataloged as a star, without recognizing him as a planet were soon enough data available to detect disturbances in the orbit of Uranus. Because of these disturbances another planet was predicted mathematically, which should eventually be found in Neptune in 1846 by Johann Gottfried Galle. Even Galileo had seen Neptune on December 27, 1612, but not recognized it as a planet.

The 20th century

1900-1930

1900 published Max Planck Planck's radiation law; a reference to the entropy of the universe and a pioneer of quantum theory. Charles Dillon Perrine observed in 1901 along with George Willis Ritchey gas nebula around the star Nova Persei, which apparently moving faster than light, a few years later he discovered two moons of Jupiter. 1906 Max Wolf discovered the first Trojan ( Achilles ) and about the same period, Johannes Franz Hartmann first evidence for the existence of interstellar matter.

Henry Norris Russell 1913 developed building upon the work of Ejnar Hertzsprung called the Hertzsprung -Russell diagram. This is a work based on classification of spectral method which can be derived on the state of development of stars from the evidence.

On June 30, 1908, the huge impact of the Tunguska meteorite was carried out (40 km2 devastated ) and 1920 in South West Africa (now Namibia) the discovery of the heaviest iron meteorites of all time ( Hoba meteorite, about 60 tons, 2.7 × 2.7 × 0.9 m). 1923 succeeded, inter alia, Edwin Hubble of the evidence that the Andromeda galaxy (M 31) is far outside the Milky Way, so it also gives other galaxies. Georges Lemaître in 1927 took place with the help of proven Milton Lasell Humason redshift the expansion of the universe. 1929 put Hubble convincing a linear relationship between redshift and distance of galaxies dar. Although his calculations have since been improved several times, carrying the thus calculated fundamental quantity of cosmology its name ( Hubble constant ). The resultant of this size Hubble time means the time started at the computationally the expansion of the universe has ( Big Bang ). Hubble self-calculated some 2 billion years; nowadays a value of nearly 14 billion years is postulated.

Neptune, which had been blamed for path deviations of Uranus, had been indeed found in 1846, but in the paths of the two planets, there were still unexplained deviations. So we continued to search for a hypothetical ninth planet, "Trans Neptune ".

In this search, Percival Lowell had photographed Pluto in 1915, but did not recognize him at this time as a planet. It was only on February 18, 1930 he was discovered by Clyde Tombaugh at Lowell founded Lowell Observatory by comparisons of some images of the sky at the blink comparator on photographic plates. Pluto was referred to in the recent past as the ninth planet.

Mid-20th century

In the course of his work at the observatory on the Pic du Midi de Bigorre was Bernard Lyot that the surface of the moon has properties of volcanic dust and sand storms occur on Mars. In 1931 Karl Guthe Jansky radio source "Sagittarius A". In subsequent years, then developed 1933 Walter Baade and Fritz Zwicky their theories about the transition from supernovae in neutron stars: The matter density there had to correspond to the density of atomic nuclei. The answer to the question of what is going on in stars before they collapse to such neutron stars, succeeded in 1938 Hans Bethe and Carl Friedrich von Weizsäcker, who discovered the hydrogen fusion to helium in the CN- cycle ( stellar fusion process, Bethe- Weizsäcker - cycle; in the same year found Nicholson the 10th and 11th moon of Jupiter, Lysithea and Carme ). Thus, one could assume that star light up and burn up their hydrogen fuel is burned by thermonuclear hydrogen fusion. Then there is a " helium flash ", is fused in consequence of helium into heavier elements. In 1965 Kippenhahn, Thomas, Weigert and other astronomers and nuclear physicists discovered that the fusion of hydrogen and helium in the giant star also can run side by side (from about three solar masses ). The final stage of these processes is then a black hole.

A first radar contact with a celestial body succeeded in 1946, on January 10 (first radar echo from the moon, path length 2.4 seconds ). In 1951 the discovery of the cosmic 21 -cm radio emission ( from interstellar hydrogen), and later the discovery of the 2.6 - mm - radiation ( from carbon monoxide). First time in 1956 radio radiation from electrical discharges in the atmosphere of Venus has been received. 1964 the 3K background radiation discovered ( "Echo of the Big Bang "). Radio astronomy was invented.

The 1970s

On May 12 In 1971 in Effelsberg, Eifel, the first German radio telescope in operation. But even in optical astronomy continued unabated: In 1973, James Van Allen, a systematic sky survey before, per square degree were down to the brightness of only 20 m) 31,600 stars and 500 galaxies registered, ie 1.3 billion stars and 20 million galaxies ( with each about 200 billion stars ). Meanwhile, drafted in 1974 Stephen Hawking 's theory of the emission of virtual particles from black holes. In the same year, on March 29, Mariner 10 reached using the swing-by technique (Venus Passage February 5, 1974 ) for the first time a probe the innermost planet Mercury ( Mercury more passages September 21, 1974, March 16, 1975, etc. - all 176 days ). On 10 March 1977, the rings of Uranus were first described.

Many activities in astronomy and space were from the mid-70s the question of whether there were other habitable or even inhabited worlds. A first active attempt to contact extraterrestrial civilizations was taken on November 16, 1974 ( the emission of a 1.679 -kB radio signal to the globular cluster M13; signal arrival there: around the year 27,000 AD). 1976 succeeded Joachim Trümper the discovery of a stellar magnetic field on Super 58- keV radiation of gyrating electrons in HZ Herculis: 5 x 1012 gauss ( Earth's magnetic field at the surface: about 0.5 Gauss ). In 1977, Charles Kowal the first centaur Chiron ( also asteroid, diameter 200-600 km, orbital radius from 8.5 to 18.9 AU).

Space - probes

On March 3, 1972, NASA launched the Pioneer 10 probe It was December 3, 1973, the first spacecraft that flew past the planet Jupiter. The sister probe Pioneer 11 lifted on April 6, 1973 from, happened on December 3, 1974 Jupiter and flew on 1 September 1979 as a first probe on Saturn over.

On September 5, 1977, NASA launched Voyager 1, which succeeded a passage to Jupiter km journey on 5 March 1979 675 million, their Saturn Passage followed in November 1980. On August 20th In 1978, with Voyager 2, the most successful swing-by spacecraft all times in the outer solar system ( mission data: Jupiter passage July 9, 1979, Saturn passage, Uranus flyby in January 1986, Neptune passage 1989), and even when she went on the trip, James W. Christy announced the discovery of Pluto moon Charon. 1977/78 was discovered in the Far of the universe for the first time organic molecules in the interstellar medium: eg acetic acid, Methylcyan, amino methane, ethanol, etc., a radio astronomical indication of a possible chemical evolution. The unmanned space hit the limits of our solar system: 1979/1980 discovery of many Jupiter and Saturn moons with Pioneer 11 and Voyager 2 in 1983 happened Pioneer 10 was the first spacecraft to Pluto - eleven years after its launch. 1984 Erstfotografie and Erstdurchflug rings of Saturn.

The 1980s and 1990s

The probe ISEE -3 flew (1985, September 11 ) for the first time by a comet tail (with gas analysis: probe ISEE -3 at Giacobini - Zinner ). In the Stellar astronomy supernova of 1987 was regarded as the sensation of the 80s (24 February: initial registration and photography of a supernova eruption in the Large Magellanic Cloud (LMC ), the neutrinos arrived on Earth even before the first optically perceptible signals. the tools made available to astronomers available, were always better, more accurate, more complicated - but with the beginning of the 90s the first time it was possible to make optical observations from outside the disturbing atmosphere: on April 24, 1990, NASA announced the. launch of the Hubble Space Telescope to the space Shuttle discovery the new observation instrument allowed - free of interference from the Earth's atmosphere - in the following years, sky shots of new, great resolution on August 6, 1993, came as the discovery of nitrogen ice on Pluto (instead of. previously suspected methane ice ) on December 27, 1999, a repair of the Hubble space Telescope was required -. , it helped so and Others still in the discovery and Erstfotografie of brown dwarfs and giant " super planet " outside our solar system.

Also probes explored the solar system continues: Galileo reached on 28 August asteroids Ida and was October 29, 1991 at Gaspra, Ulysses flew on 13 September 1994 on the sun and the South Pole Galileo landing capsule on 7 December 1995 even in the atmosphere of Jupiter For the first time the gaseous envelope of a gas planet could be studied spectroscopically. Alan Hale and Thomas Bopp published the discovery of the comet on July 22, 1995 Hale-Bopp near the orbit of Jupiter. The comet reached in March 1997, an apparent magnitude of -1m ( He was 130 times brighter than Halley's Comet ). Evidence of extraterrestrial life should have been discovered in 1996 in the from Mars meteorite ALH 84001 Antarctic (Age 3.6 billion years ) his ( controversial ).

Planets in other solar systems

With the discovery of a first non- stellar celestial body beyond our solar system astronomy made ​​a rapid development in the field of exoplanet search by: on December 12, 1984 Mc Carthy reported, inter alia, include first of a non- stellar celestial body outside the solar system, IR astronomy: He turned out itself as a " brown dwarf " star at Van Briesbroeck 8 (distance 21 light years, about 30-80 Jupiter masses). Mid-1990s were first exoplanets, ie planets outside the solar system found, first to a pulsar, 1995, a main sequence star. Since then, the number of known exoplanets has grown steadily.

Conclusion of the 20th century

Voyager 1 space probe, which was launched in 1977, is the most distant from the earth, man-made object. The distance is estimated to be about 16 light-hours, on the presumed boundary of the heliosphere. The probe was still sends signals, and this is expected to do by 2020.

Over a century ago began with the search for trans-Neptunian objects in the Kuiper belt, the outer region of our solar system. Your list, the list of trans-Neptunian objects has become long.

The understanding of the physical world through the Astronomy apply the proposal Arthur Eddington in 1920 to pull the nuclear fusion as an energy source of the stars into account, and the recognition of the spiral nebulae as extragalactic objects by Edwin Hubble in 1923, and whose idea of an expanding universe of 1929, the he developed after a comparison between distance and recession velocity of galaxies, as milestones. The model of the expanding from a big bang out universe is now generally accepted.

Albert Einstein delivered with its special and general relativity, the basis for many theories of modern astrophysics. Thus, based, for example the above-mentioned nuclear fusion on the equivalence of mass and energy, certain extreme objects such as neutron stars and black holes require the general theory of relativity to describe and even cosmology is largely based on this theory.

With the advent of space travel in the second half of the 20th century became astronomy opportunity to visit some of her lying in the solar system research subjects directly and to make scientific analyzes on site. But at least as important was the abolition of restrictions on the Earth's atmosphere, with the new wavelength regions and thus new windows opened by satellite-based observatories in the ultraviolet astronomy, X-ray astronomy and infrared astronomy in the universe, of which yielded any previously unsuspected findings. With the study of neutrinos the sun and the supernova 1987A, the observation of particle showers of cosmic rays and the construction of gravitational wave detectors modern astronomy also first began to examine other types of radiation than the electromagnetic radiation. At the same time the visual astronomy offered by telescopes such as the Hubble Space Telescope or the Very Large Telescope new observation opportunities.

The 21st century

In the 21st century, the cosmos was just like his objects in the far outer space further research on the building blocks of matter. For example, many more extrasolar planets ( exoplanets Planemos ) were discovered. In May 2006, already more than 130 planetary systems were known. In the hitherto discovered planet is a life similar to that on the Earth, so with aqueous Biochemistry excluded, however, is the discovery of Earth-like planet yet outside of the technical possibilities. With methods such as interferometry, however, astronomers hope to soon search for Earth-sized planets around neighboring stars and to ray spectra of their atmospheres latest in the next generation.

On 11 June 2007, NASA announced a new " record ". You could prove that 55 Cancri ( fixed star in the constellation Cancer, about 41 light-years away ) is orbited by five planets. One of the newly discovered planet has 45 Earth masses and orbits 55 Cancri in the habitable zone, ie in the zone in the water can be liquid.