The spacecraft Galileo took this picture of the Earth and Moon from space as it headed out to its encounter with the planet Jupiter. The photo was taken from a distance of about 6.2 million kilometers from the Earth. The Moon is in the foreground, moving from left to right. Galileo was then fairly close to the orbital plane of the Moon and nearly in line with the Earth and Moon, which foreshortened the distance between them and made them appear to be closer than their actual orbital separation.
This is one of a series of photographs of the eclipse of the Sun which was taken from the Apollo 12 spacecraft during its transearth journey home from the Moon. This view was created when the Earth moved directly between the Sun and the Apollo 12 spacecraft.
This multiple exposure image was made at the Observatorio del Teide Tenerife of the Instituto de Astrofisica de Canarias (Canary Islands) on April 3, 1996. It shows the progression of the Earth's shadow across the surface of the Moon during the lunar eclipse of that date for an hour-long time period between 22:30 and 23:30 Universal Time. Examination of these images, which were deliberately overexposed in a consistent way, clearly reveals the circular shape of the shadow of the Earth.
The two central columns of characters of the inscription on this ancient Chinese oracle-bone, dating from about 1300 BCE, reads, "on the 7th day of the month, a chi-ssu day, a great new star appeared in company with Antares." From Colin A. Ronan's book The Shorter Science and Civilisation in China: An Abridgement of Joseph Needham's Original Text.
Distance Ratio by Aristarchus"
This image is from a tenth century Greek copy of a noteworthy work by Aristarchus of Samos written in the second century BCE entitled "On the Distances and Sizes of the Sun and Moon," in which he calculates the ratio of the distance between the Earth and Sun to that between the Earth and the Moon. (His estimate was more than an order of magnitude too small, but the fault was in his lack of accurate instruments rather than in his correct method of reasoning.) This detail compares the line subtending the arc dividing the light and dark portions of the Moon in a lunar eclipse with the relative diameters of the Moon and Sun. Aristarchus also found an improved value for the length of the solar year.
Claudius Ptolemy, who lived in the second century CE, wrote the extremely influential treatise that came to be called the "Almagest" in about CE 150. This work covered elements of spherical astronomy, solar, lunar, and planetary theory, eclipses, and the fixed stars. It remained the definitive authority on its subject for nearly fifteen hundred years. This image shows a detail from Book VI Chapter 7 of a late-1400's copy of George Trebizond's Latin translation (ca. 1451) of this work. The drawing illustrates the computation of the duration of solar and lunar eclipses. This elaborate manuscript of the translation, with the figures drawn in several colors, was dedicated to Pope Sixtus IV by George's son Andreas.
Source: Library of Congress Vatican Exhibit, Greek Astronomy, Vat. lat. 2055 fol. 101 verso math17 NS.08
This image shows a detail from Book X Chapter 7 of a thirteenth century translation of Ptolemy's Almagest made from Arabic to Latin in Spain in 1175 by Gerard of Cremona. This image illustrates Ptolemy's
kinematic model for the motion of the superior planets -- Mars, Jupiter, and Saturn. According to this geocentric model, the earth is at rest at (e) and the planets move uniformly with respect to a point (r) which is separated from the center of their spheres, (d). This device produced predictions for the paths of the planets in the sky that closely approximate those resulting from the elliptical orbits in which planets actually move.
Nasir ad-Din at-Tusi (1201-1274) was among the Arabic astronomers of the late thirteenth century at the observatory of Maragha in Persia who modified Ptolemy's models based on mechanical principles in order to preserve the uniform rotation of spheres. This early Arabic manuscript contains his principal work on the subject, the "Tadhkira fi ilm al-Haya" (Memoir on Astronomy). The figure shown in this detail from a fourteenth-century copy of his manuscript is his ingenious device for generating rectilinear motion along the diameter of the outer circle from two circular motions.
This panel, from a 1504 painting by Hieronymous Bosch called The Garden of Earthly Delight, is part of a large, 3-part piece called a triptych. The painting was probably made for the private
enjoyment of a noble family. It is named for a luscious garden painted in the central panel (not shown). The portion linked here is from one of the outer wings, or shutters, and depicts a stylized medieval view of the third day of the creation of the world, including a flat Earth with clouds floating in a spherical firmament, and a void surrounding the spherical bubble enclosing the Earth. Although this point of view was not prevalent or widely shared among educated members of the society in the Middle Ages, who had inherited much of their astronomical knowledge from documents such as those shown above, it did hold a certain amount of sway among members of the general public.
Also available via WebMuseum, Bosch, Hieronymus, "The Garden of Earthly Delight (Outer wings)"
This image shows the order and concentricity of the orbits of the newly revived heliocentric model of the solar system proposed in the early 1500's by Nicholas Copernicus. The page shown is from the "autograph" (intermediate between a rough and a fair copy), which was Copernicus's own version of the manuscript. This copy was made between 1520 and 1541, and had remained in the author's hands until his death in 1543. It is preserved in the Jagiellonian Library, Cracow, Poland.
Galileo Galilei constructed his first telescope in July of 1609, based on reports of the existence of other models, which he had not seen, at different locations in Europe. It wasn't long before he began to make and record a series of startling observations, including the discovery of innumerable stars never seen before, mountains on the moon, four satellites of Jupiter which moved, and other celestial phenomena that increased his personal belief in the Copernican System. The phenomena which were revealed little by little through his use of ever-larger lenses were described and illustrated by Galileo in "Sidereus Nuncius" (Starry Messenger), which caused an overnight sensation.
Sir Isaac Newton drew this diagram of the orbit of the comet of 1680 to illustrate his calculations regarding its properties in his master work Philosophiae Naturalis Principia Mathematica, usually known as the Principia. Building on Kepler's Laws of Planetary Motion and on suggestions from others (most notably Robert Hooke) that elliptical orbits must follow from an inverse square force law of attraction to the parent, Newton went much further and solved the problem completely in the Principia by proving that an inverse square law must have solutions that can produce elliptical, parabolic or hyperbolic orbits, and proposed his now famous Law of Universal Gravitation, which states that all objects in the universe attract all other objects with a force that is proportional to the product of their masses and inversely proportional to the square of the distance between them.
This is a condensed detail from the cover page of a 1645 copy of the work "De Numeris Stellarum et Motibus" by Abu-Abdallah Muhammad Ibn-Gabir Battani (858-929 CE), also known as Albatenius. The illustration shows medieval astronomical instruments popular at the time of publication of this edition. Several of these are of types in use since the time of the early astronomers and refined later, as shown in the examples shown in the images. The work of Albatenius and other Arab astronomers provided a vital link between mathematical progress made by early Greek astronomers and later efforts that led eventually
to the birth of modern astronomy.
Since the time of Eratosthenes in the 3rd century BCE, instruments of
this type were widely used by natural philosophers of the Alexandrian school to represent the coordinates of the celestial sphere. These "armillary spheres" consisted of graduated metallic rings designating the equator, the ecliptic and certain meridians and parallels. This "skeleton" of metal rings (armillae) was supported by a fixed ring representing the local horizon and could be adapted to the latitude and longitude of the observer. The Earth was represented at the center of this sphere, together with, in the more complicated models, the Sun, Moon and other planets. By correctly placing bodies inside the sphere and the rings, it was possible to solve problems of spherical astronomy and compute the coordinates of the stars on the celestial sphere.
Copernicus came from a middle class background and received a good standard humanist education, studying first at the university of Krakow (then the capital of Poland) and then traveling to Italy where he studied medical sciences, Latin, Greek, mathematics and law at at the universities of Bologna, Padua and Ferrara. When he returned to his native land of Poland, Copernicus practised medicine, though his official employment was as a canon in the cathedral chapter, working under a maternal uncle who was Bishop of Olsztyn (Allenstein) and then of Frombork (Frauenburg). While he was in Italy, Copernicus visited
Rome, and it seems to have been for friends there that in about 1513 he wrote a short account of what has since become known as the Copernican theory, namely that the Sun (not the Earth) is at rest in the center of the Universe. The work of proving that the term "Universe" should be modified to "Solar System" in this statement and of providing a mathematical and physical foundation for this idea fell to later workers. Copernicus lived from 1473 to 1543.
This portrait of the then-famous astronomer was made when he was 55 years old, shortly before his death, by E. Desrochers. Tycho Brahe, Galileo Galilei, and Johannes Kepler were contemporaries; Tycho preceded Kepler as Imperial Mathematician to the Holy Roman Empire. His extensive, carefully made collection of measurements, which Brahe personally thought would provide evidence to validate and extend the Ptolemaic geocentric system, actually provided Kepler and others with the raw material they would need to confirm that Copernicus was right.
Galileo was born in 1564 in Pisa. In the summer of 1609, he heard about a spyglass that a Dutchman had shown in Venice. From these reports, and using his own technical skills as a mathematician and as a workman, Galileo made a series of telescopes whose optical performance was much better than that of the Dutch instrument. The astronomical discoveries he made with his telescopes were described in a short book called Starry Messenger (Sidereus Nuncius), the cover to which is shown above. The discoveries made with this and
other telescopes quickly transformed the entire field of astronomy from the theoretical philosophy of motion of heavenly objects into a full-fledged experimental science.
Kepler was a devout, but not completely orthodox, Lutheran. He attended the University of Tübingen, where he studied both Ptolemaic and Copernican astronomy before taking a position teaching mathematics at Graz. He took over the position as the Imperial Mathematician to the Holy Roman Emperor, Rudolph II, in Prague from Tycho Brahe in 1601. In a series of publications between 1596 and 1619, building on Brahe's extensive experimental observations, Kepler proved that planets move round the Sun in elliptical orbits and laid out three mathematical laws of planetary motion. His Rudolphine Tables (1627), based on Tycho's observations and these laws, proved to be accurate over a long time scale and their success did
much to gain general acceptance for heliocentric astronomy.
This is the earliest portrait of Newton to survive. It was painted when Newton was in London as a member of the Convention Parliament, following the "Glorious Revolution" of 1688. Newton was then 46 years old. The artist was Godfrey Kneller, a prominent portrait painter of his day. For a complete biography, see the
page on Sir Isaac Newton at the MacTutor History of Mathematics Archive.
For biographies and more insight into the work of these and other
mathematicians and astronomers, see the MacTutor History of Mathematics Archive, which is the source for some of the information presented above, and the History of Women in Astronomy at San Francisco State University. Portraits of other scientists along with some examples of classical art related to astronomy can be found in the
Windows to the Universe Art Archives.
Earth and Moon from Space
Apollo Solar Eclipse
Complete Lunar Eclipse Image Sequence
Oldest Record of a Nova
Calculation of Sun/Moon Distance Ratio by Aristarchus
Detail 1 from Ptolemy's Almagest
Detail 2 from Ptolemy's Almagest
Detail from ad-Din at-Tusi, Tadhkira
Medieval View of the World
Illustration from De Revolutionibus
Galileo's Starry Messenger
Newton's Sketch Of The Orbit For The Comet of 1680
Detail from Albatenius's Stellarum
Large Armillary Sphere
Nicolaus Copernicus
Tycho Brahe in 1601
Galileo Galilei
Johannes Kepler
Isaac Newton in 1689