Hypatia was a Hellenistic Neoplatonist philosopher and mathematician, who lived in Alexandria, Egypt part of the Eastern Roman Empire. She was a prominent thinker of the Neoplatonic school in Alexandria where she taught philosophy and astronomy, she is the first female mathematician. Hypatia was renowned in her own lifetime as a wise counselor, she is known to have written a commentary on Diophantus's thirteen-volume Arithmetica, which may survive in part, having been interpolated into Diophantus's original text, another commentary on Apollonius of Perga's treatise on conic sections, which has not survived. Many modern scholars believe that Hypatia may have edited the surviving text of Ptolemy's Almagest, based on the title of her father Theon's commentary on Book III of the Almagest. Hypatia is known to have constructed astrolabes and hydrometers, but did not invent either of these, which were both in use long before she was born. Although she herself was a pagan, she was tolerant towards Christians and taught many Christian students, including Synesius, the future bishop of Ptolemais.
Ancient sources record that Hypatia was beloved by pagans and Christians alike and that she established great influence with the political elite in Alexandria. Towards the end of her life, Hypatia advised Orestes, the Roman prefect of Alexandria, in the midst of a political feud with Cyril, the bishop of Alexandria. Rumors spread accusing her of preventing Orestes from reconciling with Cyril and, in March 415 AD, she was murdered by a mob of Christians led by a lector named Peter. Hypatia's murder shocked the empire and transformed her into a "martyr for philosophy", leading future Neoplatonists such as Damascius to become fervent in their opposition to Christianity. During the Middle Ages, Hypatia was co-opted as a symbol of Christian virtue and scholars believe she was part of the basis for the legend of Saint Catherine of Alexandria. During the Age of Enlightenment, she became a symbol of opposition to Catholicism. In the nineteenth century, European literature Charles Kingsley's 1853 novel Hypatia, romanticized her as "the last of the Hellenes".
In the twentieth century, Hypatia became seen as an icon for women's rights and a precursor to the feminist movement. Since the late twentieth century, some portrayals have associated Hypatia's death with the destruction of the Library of Alexandria, despite the historical fact that the library no longer existed during Hypatia's lifetime. Hypatia was the daughter of the mathematician Theon of Alexandria. According to classical historian Edward J. Watts, Theon was the head of a school called the "Mouseion", named in emulation of the Hellenistic Mouseion, whose membership had ceased in the 260s AD. Theon's school was exclusive prestigious, doctrinally conservative. Theon rejected the teachings of Iamblichus and may have taken pride in teaching a pure, Plotinian Neoplatonism. Although he was seen as a great mathematician at the time, Theon's mathematical work has been deemed by modern standards as "minor", "trivial", "completely unoriginal", his primary achievement was the production of a new edition of Euclid's Elements, in which he corrected scribal errors, made over the course of nearly 700 years of copying.
Theon's edition of Euclid's Elements became the most widely-used edition of the textbook for centuries and totally supplanted all other editions. Nothing is known about Hypatia's mother, never mentioned in any of the extant sources. Theon dedicates his commentary on Book IV of Ptolemy's Almagest to an individual named Epiphanius, addressing him as "my dear son", indicating that he may have been Hypatia's brother, but the Greek word Theon uses does not always mean "son" in the biological sense and was used to signal strong feelings of paternal connection. Hypatia's exact year of birth is still under debate, with suggested dates ranging from 350 to 370 AD. Many scholars have followed Richard Hoche in inferring that Hypatia was born around 370. According to a description of Hypatia from the lost work Life of Isidore by the Neoplatonist historian Damascius, preserved in the entry for her in the Suda, a tenth-century Byzantine encyclopedia, Hypatia flourished during the reign of Arcadius. Hoche reasoned that Damascius's description of her physical beauty would imply that she was at most 30 at that time, the year 370 was 30 years prior to the midpoint of Arcadius's reign.
In contrast, theories that she was born as early as 350 are based on the wording of the chronicler John Malalas, who calls her old at the time of her death in 415. Robert Penella argues that both theories are weakly based, that her birth date should be left unspecified. Hypatia was a Neoplatonist, like her father, she rejected the teachings of Iamblichus and instead embraced the original Neoplatonism formulated by Plotinus; the Alexandrian school was renowned at the time for its philosophy and Alexandria was regarded as second only to Athens as the philosophical capital of the Greco-Roman world. Hypatia taught students from all over the Mediterranean. According to Damascius, she lectured on the writings of Aristotle, he states that she walked through Alexandria in a tribon, a kind of cloak associated with philosophers, giving impromptu public lectures. According to Watts, two main varieties of Neoplatonism were taught in Alexandria during the late fourth century; the first was the overtly pagan religious Neoplatonism taught at the Serapeum, influenced by the teachings of Iamblichus.
The second variety was the more moderate and less polemical variety c
Deuterium is one of two stable isotopes of hydrogen. The nucleus of deuterium, called a deuteron, contains one proton and one neutron, whereas the far more common protium has no neutron in the nucleus. Deuterium has a natural abundance in Earth's oceans of about one atom in 6420 of hydrogen, thus deuterium accounts for 0.0156% of all the occurring hydrogen in the oceans, while protium accounts for more than 99.98%. The abundance of deuterium changes from one kind of natural water to another; the deuterium isotope's name is formed from the Greek deuteros, meaning "second", to denote the two particles composing the nucleus. Deuterium was named in 1931 by Harold Urey; when the neutron was discovered in 1932, this made the nuclear structure of deuterium obvious, Urey won the Nobel Prize in 1934. Soon after deuterium's discovery and others produced samples of "heavy water" in which the deuterium content had been concentrated. Deuterium is destroyed in the interiors of stars faster. Other natural processes are thought to produce only an insignificant amount of deuterium.
Nearly all deuterium found in nature was produced in the Big Bang 13.8 billion years ago, as the basic or primordial ratio of hydrogen-1 to deuterium has its origin from that time. This is the ratio found in the gas giant planets, such as Jupiter. However, other astronomical bodies are found to have different ratios of deuterium to hydrogen-1; this is thought to be a result of natural isotope separation processes that occur from solar heating of ices in comets. Like the water cycle in Earth's weather, such heating processes may enrich deuterium with respect to protium; the analysis of deuterium/protium ratios in comets found results similar to the mean ratio in Earth's oceans. This reinforces theories; the deuterium/protium ratio of the comet 67P/Churyumov-Gerasimenko, as measured by the Rosetta space probe, is about three times that of earth water. This figure is the highest yet measured in a comet. Deuterium/protium ratios thus continue to be an active topic of research in both astronomy and climatology.
Deuterium is represented by the chemical symbol D. Since it is an isotope of hydrogen with mass number 2, it is represented by 2H. IUPAC allows 2H, although 2H is preferred. A distinct chemical symbol is used for convenience because of the isotope's common use in various scientific processes, its large mass difference with protium confers non-negligible chemical dissimilarities with protium-containing compounds, whereas the isotope weight ratios within other chemical elements are insignificant in this regard. In quantum mechanics the energy levels of electrons in atoms depend on the reduced mass of the system of electron and nucleus. For the hydrogen atom, the role of reduced mass is most seen in the Bohr model of the atom, where the reduced mass appears in a simple calculation of the Rydberg constant and Rydberg equation, but the reduced mass appears in the Schrödinger equation, the Dirac equation for calculating atomic energy levels; the reduced mass of the system in these equations is close to the mass of a single electron, but differs from it by a small amount about equal to the ratio of mass of the electron to the atomic nucleus.
For hydrogen, this amount is about 1837/1836, or 1.000545, for deuterium it is smaller: 3671/3670, or 1.0002725. The energies of spectroscopic lines for deuterium and light hydrogen therefore differ by the ratios of these two numbers, 1.000272. The wavelengths of all deuterium spectroscopic lines are shorter than the corresponding lines of light hydrogen, by a factor of 1.000272. In astronomical observation, this corresponds to a blue Doppler shift of 0.000272 times the speed of light, or 81.6 km/s. The differences are much more pronounced in vibrational spectroscopy such as infrared spectroscopy and Raman spectroscopy, in rotational spectra such as microwave spectroscopy because the reduced mass of the deuterium is markedly higher than that of protium. In nuclear magnetic resonance spectroscopy, deuterium has a different NMR frequency and is much less sensitive. Deuterated solvents are used in protium NMR to prevent the solvent from overlapping with the signal, although deuterium NMR on its own right is possible.
Deuterium is thought to have played an important role in setting the number and ratios of the elements that were formed in the Big Bang. Combining thermodynamics and the changes brought about by cosmic expansion, one can calculate the fraction of protons and neutrons based on the temperature at the point that the universe cooled enough to allow formation of nuclei; this calculation indicates seven protons for every neutron at the beginning of nucleogenesis, a ratio that would remain stable after nucleogenesis was over. This fraction was in favor of protons primarily because the lower mass of the proton favored their production; as the universe expanded, it cooled. Free neutrons and protons are less stable than helium nuclei, the protons and neutrons had a strong energetic reason to form helium-4. However, forming helium-4 requires the intermediate step of forming deuterium. Through much of the few minutes after the big bang during which nucleosynthesis could have occurred
The Moon is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite. It is the fifth-largest natural satellite in the Solar System, the largest among planetary satellites relative to the size of the planet that it orbits; the Moon is after Jupiter's satellite Io the second-densest satellite in the Solar System among those whose densities are known. The Moon is thought to have formed not long after Earth; the most accepted explanation is that the Moon formed from the debris left over after a giant impact between Earth and a Mars-sized body called Theia. The Moon is in synchronous rotation with Earth, thus always shows the same side to Earth, the near side; the near side is marked by dark volcanic maria that fill the spaces between the bright ancient crustal highlands and the prominent impact craters. After the Sun, the Moon is the second-brightest visible celestial object in Earth's sky, its surface is dark, although compared to the night sky it appears bright, with a reflectance just higher than that of worn asphalt.
Its gravitational influence produces the ocean tides, body tides, the slight lengthening of the day. The Moon's average orbital distance is 1.28 light-seconds. This is about thirty times the diameter of Earth; the Moon's apparent size in the sky is the same as that of the Sun, since the star is about 400 times the lunar distance and diameter. Therefore, the Moon covers the Sun nearly during a total solar eclipse; this matching of apparent visual size will not continue in the far future because the Moon's distance from Earth is increasing. The Moon was first reached in September 1959 by an unmanned spacecraft; the United States' NASA Apollo program achieved the only manned lunar missions to date, beginning with the first manned orbital mission by Apollo 8 in 1968, six manned landings between 1969 and 1972, with the first being Apollo 11. These missions returned lunar rocks which have been used to develop a geological understanding of the Moon's origin, internal structure, the Moon's history. Since the Apollo 17 mission in 1972, the Moon has been visited only by unmanned spacecraft.
Both the Moon's natural prominence in the earthly sky and its regular cycle of phases as seen from Earth have provided cultural references and influences for human societies and cultures since time immemorial. Such cultural influences can be found in language, lunar calendar systems and mythology; the usual English proper name for Earth's natural satellite is "the Moon", which in nonscientific texts is not capitalized. The noun moon is derived from Old English mōna, which stems from Proto-Germanic *mēnô, which comes from Proto-Indo-European *mḗh₁n̥s "moon", "month", which comes from the Proto-Indo-European root *meh₁- "to measure", the month being the ancient unit of time measured by the Moon; the name "Luna" is used. In literature science fiction, "Luna" is used to distinguish it from other moons, while in poetry, the name has been used to denote personification of Earth's moon; the modern English adjective pertaining to the Moon is lunar, derived from the Latin word for the Moon, luna. The adjective selenic is so used to refer to the Moon that this meaning is not recorded in most major dictionaries.
It is derived from the Ancient Greek word for the Moon, σελήνη, from, however derived the prefix "seleno-", as in selenography, the study of the physical features of the Moon, as well as the element name selenium. Both the Greek goddess Selene and the Roman goddess Diana were alternatively called Cynthia; the names Luna and Selene are reflected in terminology for lunar orbits in words such as apolune and selenocentric. The name Diana comes from the Proto-Indo-European *diw-yo, "heavenly", which comes from the PIE root *dyeu- "to shine," which in many derivatives means "sky and god" and is the origin of Latin dies, "day"; the Moon formed 4.51 billion years ago, some 60 million years after the origin of the Solar System. Several forming mechanisms have been proposed, including the fission of the Moon from Earth's crust through centrifugal force, the gravitational capture of a pre-formed Moon, the co-formation of Earth and the Moon together in the primordial accretion disk; these hypotheses cannot account for the high angular momentum of the Earth–Moon system.
The prevailing hypothesis is that the Earth–Moon system formed after an impact of a Mars-sized body with the proto-Earth. The impact blasted material into Earth's orbit and the material accreted and formed the Moon; the Moon's far side has a crust, 30 mi thicker than that of the near side. This is thought to be; this hypothesis, although not perfect best explains the evidence. Eighteen months prior to an October 1984 conference on lunar origins, Bill Hartmann, Roger Phillips, Jeff Taylor challenged fellow lunar scientists: "You have eighteen months. Go back to your Apollo data, go back to your computer, do whatever you have to, but make up your mind. Don't come to our conference unless you have something to say about the Moon's birth." At the 1984 conference at Kona, the giant impact hypothesis emerged as the most consensual theory. Before the conference, there were parti
Committee for Skeptical Inquiry
The Committee for Skeptical Inquiry known as the Committee for the Scientific Investigation of Claims of the Paranormal, is a program within the transnational American non-profit educational organization Center for Inquiry, which seeks to "promote scientific inquiry, critical investigation, the use of reason in examining controversial and extraordinary claims." Paul Kurtz proposed the establishment of CSICOP in 1976 as an independent non-profit organization, to counter what he regarded as an uncritical acceptance of, support for, paranormal claims by both the media and society in general. Its philosophical position is one of scientific skepticism. CSI's fellows have included notable scientists, Nobel laureates, psychologists and authors, it is headquartered in New York. In the early 1970s, there was an upsurge of interest in the paranormal in the United States; this generated concern in some quarters, where it was seen as part of a growing tide of irrationalism. In 1975, secular humanist philosopher and professor Paul Kurtz had initiated a statement, "Objections to Astrology", co-written with Bart Bok and Lawrence E. Jerome, endorsed by 186 scientists including 19 Nobel laureates and published in the American Humanist Association's newsletter The Humanist, of which Kurtz was editor.
According to Kurtz, the statement was sent to every newspaper in the United States and Canada. The positive reaction to this statement encouraged Kurtz to invite "as many skeptical researchers as could locate" to the 1976 conference with the aim of establishing a new organization dedicated to examining critically a wide range of paranormal claims. Among those invited were Martin Gardner, Ray Hyman, James Randi, Marcello Truzzi, all members of the Resources for the Scientific Evaluation of the Paranormal, a fledgling group with objectives similar to those CSI would subsequently adopt. RSEP disbanded and its members, along with others such as Carl Sagan, Isaac Asimov, B. F. Skinner, Philip J. Klass, joined Kurtz, Randi and Hyman to formally found the Committee for Scientific Investigation of Claims of the Paranormal. Kurtz, Randi and Hyman took seats on the executive board. CSICOP was launched at a specially convened conference of the AHA on April 30 and May 1, 1976. CSICOP would be funded with sales of their magazine, Skeptical Inquirer.
According to the published correspondence between Gardner and Truzzi, disagreements over what CSICOP should be showed how volatile the beginnings of the organization were. Truzzi criticised CSICOP for "acted more like lawyers" taking on a position of dismissal before evaluating the claims, saying that CSICOP took a "debunking stance". Gardner on the other hand "opposed'believers' in the paranormal becoming CSICOP members" which Truzzi supported. Gardner felt that Truzzi "conferred too much respectability to nonsense"; the formal mission statement, approved in 2006 and still current, states:The Committee for Skeptical Inquiry promotes science and scientific inquiry, critical thinking, science education, the use of reason in examining important issues. It encourages the critical investigation of controversial or extraordinary claims from a responsible, scientific point of view and disseminates factual information about the results of such inquiries to the scientific community, the media, the public.
A shorter version of the mission statement appears in every issue: "... promotes scientific inquiry, critical investigation, the use of reason in examining controversial and extraordinary claims." A previous mission statement referred to "investigation of paranormal and fringe-science claims", but the 2006 change recognized and ratified a wider purview for CSI and its magazine, Skeptical Inquirer, that includes "new sciencerelated issues at the intersection of science and public concerns, while not ignoring core topics". A history of the first two decades is available in The Encyclopedia of the Paranormal published in 1998 by S. I. editor Kendrick Frazier. In 2018, Frazier reemphasized the importance of the Committee's work by saying that "e need independent, evidence-based, science-based critical investigation and inquiry ow more than at any other time in our history." Paul Kurtz was inspired by the 1949 Belgian organization Comité Para, whose full name was Comité Belge pour l'Investigation Scientifique des Phénomènes Réputés Paranormaux.
In 1976, the proposed name was "Committee for the Scientific Investigation of Claims of the Paranormal and Other Phenomena", shortened to "Committee for the Scientific Investigation of Claims of the Paranormal." The initial acronym, "CSICP" was difficult to pronounce and so was changed to "CSICOP." According to James Alcock, it was never intended to be "Psi Cop", a nickname that some of the group's detractors adopted. In November 2006, CSICOP further shortened its name to "Committee for Skeptical Inquiry", pronounced C-S-I; the reasons for the change were to create a name, shorter, more "media-friendly", to remove "paranormal" from the name, to reflect more the actual scope of the organization with its broader focus on critical thinking and rationality in general, because "it includes the root words of our magazine's title, the Skeptical Inquirer". In order to carry out its mission, the Committee "maintains a network of people interested in critically examining paranormal, fringe science, other claims, in contributing to consumer education.
Italian Renaissance painting
Italian Renaissance painting is the painting of the period beginning in the late 13th century and flourishing from the early 15th to late 16th centuries, occurring in the Italian peninsula, at that time divided into many political states, some independent but others controlled by external powers. The painters of Renaissance Italy, although attached to particular courts and with loyalties to particular towns, nonetheless wandered the length and breadth of Italy occupying a diplomatic status and disseminating artistic and philosophical ideas; the city of Florence in Tuscany is renowned as the birthplace of the Renaissance, in particular of Renaissance painting, although in the era Rome and Venice assumed increasing importance in painting. A detailed background is given in the companion articles Renaissance architecture. Italian Renaissance painting is most be divided into four periods: the Proto-Renaissance, the Early Renaissance, the High Renaissance, Mannerism; the dates for these periods represent the overall trend in Italian painting and do not cover all painters as the lives of individual artists and their personal styles overlapped these periods.
The Proto-Renaissance begins with the professional life of the painter Giotto and includes Taddeo Gaddi and Altichiero. The Early Renaissance style was started by Masaccio and further developed by Fra Angelico, Paolo Uccello, Piero della Francesca, Sandro Botticelli, Domenico Ghirlandaio and Giovanni Bellini; the High Renaissance period was that of Leonardo da Vinci, Raphael, Andrea del Sarto, Giorgione, the latter works of Giovanni Bellini, Titian. The Mannerist period, dealt with in a separate article, included the latter works of Michelangelo, as well as Pontormo, Parmigianino and Tintoretto; the influences upon the development of Renaissance painting in Italy are those that affected Philosophy, Architecture, Science and other aspects of society. The following is a summary of points dealt with more in the main articles that are cited above. A number of Classical texts, lost to Western European scholars for centuries, became available; these included Philosophy, Drama, Science, a thesis on the Arts and Early Christian Theology.
The resulting interest in Humanist philosophy meant that man's relationship with humanity, the universe and with God was no longer the exclusive province of the Church. A revived interest in the Classics brought about the first archaeological study of Roman remains by the architect Brunelleschi and sculptor Donatello; the revival of a style of architecture based on classical precedents inspired a corresponding classicism in painting, which manifested itself as early as the 1420s in the paintings of Masaccio and Paolo Uccello. Simultaneous with gaining access to the Classical texts, Europe gained access to advanced mathematics which had its provenance in the works of Byzantine and Islamic scholars; the advent of movable type printing in the 15th century meant that ideas could be disseminated and an increasing number of books were written for a broad public. The development of oil paint and its introduction to Italy had lasting effects on the art of painting; the establishment of the Medici Bank and the subsequent trade it generated brought unprecedented wealth to a single Italian city, Florence.
Cosimo de' Medici set a new standard for patronage of the arts, not associated with the church or monarchy. The serendipitous presence within the region of Florence of certain individuals of artistic genius, most notably Giotto, Brunelleschi, Piero della Francesca, Leonardo da Vinci and Michelangelo, formed an ethos that supported and encouraged many lesser artists to achieve work of extraordinary quality. A similar heritage of artistic achievement occurred in Venice through the talented Bellini family, their influential inlaw Mantegna, Giorgione and Tintoretto. Much painting of the Renaissance period was commissioned for the Catholic Church; these works were of large scale and were cycles painted in fresco of the Life of Christ, the Life of the Virgin or the life of a saint St. Francis of Assisi. There were many allegorical paintings on the theme of Salvation and the role of the Church in attaining it. Churches commissioned altarpieces, which were painted in tempera on panel and in oil on canvas.
Apart from large altarpieces, small devotional pictures were produced in large numbers, both for churches and for private individuals, the most common theme being the Madonna and Child. Throughout the period, civic commissions were important. Local government buildings were decorated with frescoes and other works both secular, such as Ambrogio Lorenzetti's The Allegory of Good and Bad Government, religious, such as Simone Martini's fresco of the Maestà, in the Palazzo Pubblico, Siena. Portraiture was uncommon in the 14th and early 15th centuries limited to civic commemorative pictures such as the equestrian portraits of Guidoriccio da Fogliano by Simone Martini, 1327, in Siena and, of the early 15th century, John Hawkwood by Uccello in Florence Cathedral and its companion portraying Niccolò da Tolentino by Andrea del Castagno. During the 15th century portraiture became common often formalised profile portraits but three-quarter face, bust-length portraits. Patrons of art works such as altarpieces and fresco cycles were included in the scenes, a notable example being the inclusion of the Sassetti and Medici families in Domenico Ghirlandaio's cycle in the Sassetti Chapel.
Portraiture was to become a major subject for High Renaissance painters such as Raphael and Titian
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The first detection of radio waves from an astronomical object was in 1932, when Karl Jansky at Bell Telephone Laboratories observed radiation coming from the Milky Way. Subsequent observations have identified a number of different sources of radio emission; these include stars and galaxies, as well as new classes of objects, such as radio galaxies, quasars and masers. The discovery of the cosmic microwave background radiation, regarded as evidence for the Big Bang theory, was made through radio astronomy. Radio astronomy is conducted using large radio antennas referred to as radio telescopes, that are either used singularly, or with multiple linked telescopes utilizing the techniques of radio interferometry and aperture synthesis; the use of interferometry allows radio astronomy to achieve high angular resolution, as the resolving power of an interferometer is set by the distance between its components, rather than the size of its components.
Before Jansky observed the Milky Way in the 1930s, physicists speculated that radio waves could be observed from astronomical sources. In the 1860s, James Clerk Maxwell's equations had shown that electromagnetic radiation is associated with electricity and magnetism, could exist at any wavelength. Several attempts were made to detect radio emission from the Sun including an experiment by German astrophysicists Johannes Wilsing and Julius Scheiner in 1896 and a centimeter wave radiation apparatus set up by Oliver Lodge between 1897 and 1900; these attempts were unable to detect any emission due to technical limitations of the instruments. The discovery of the radio reflecting ionosphere in 1902, led physicists to conclude that the layer would bounce any astronomical radio transmission back into space, making them undetectable. Karl Jansky made the discovery of the first astronomical radio source serendipitously in the early 1930s; as an engineer with Bell Telephone Laboratories, he was investigating static that interfered with short wave transatlantic voice transmissions.
Using a large directional antenna, Jansky noticed that his analog pen-and-paper recording system kept recording a repeating signal of unknown origin. Since the signal peaked about every 24 hours, Jansky suspected the source of the interference was the Sun crossing the view of his directional antenna. Continued analysis showed that the source was not following the 24-hour daily cycle of the Sun but instead repeating on a cycle of 23 hours and 56 minutes. Jansky discussed the puzzling phenomena with his friend and teacher Albert Melvin Skellett, who pointed out that the time between the signal peaks was the exact length of a sidereal day. By comparing his observations with optical astronomical maps, Jansky concluded that the radiation source peaked when his antenna was aimed at the densest part of the Milky Way in the constellation of Sagittarius, he concluded that since the Sun were not large emitters of radio noise, the strange radio interference may be generated by interstellar gas and dust in the galaxy.
Jansky announced his discovery in 1933. He wanted to investigate the radio waves from the Milky Way in further detail, but Bell Labs reassigned him to another project, so he did no further work in the field of astronomy, his pioneering efforts in the field of radio astronomy have been recognized by the naming of the fundamental unit of flux density, the jansky, after him. Grote Reber was inspired by Jansky's work, built a parabolic radio telescope 9m in diameter in his backyard in 1937, he began by repeating Jansky's observations, conducted the first sky survey in the radio frequencies. On February 27, 1942, James Stanley Hey, a British Army research officer, made the first detection of radio waves emitted by the Sun; that year George Clark Southworth, at Bell Labs like Jansky detected radiowaves from the sun. Both researchers were bound by wartime security surrounding radar, so Reber, not, published his 1944 findings first. Several other people independently discovered solar radiowaves, including E. Schott in Denmark and Elizabeth Alexander working on Norfolk Island.
At Cambridge University, where ionospheric research had taken place during World War II, J. A. Ratcliffe along with other members of the Telecommunications Research Establishment that had carried out wartime research into radar, created a radiophysics group at the university where radio wave emissions from the Sun were observed and studied; this early research soon branched out into the observation of other celestial radio sources and interferometry techniques were pioneered to isolate the angular source of the detected emissions. Martin Ryle and Antony Hewish at the Cavendish Astrophysics Group developed the technique of Earth-rotation aperture synthesis; the radio astronomy group in Cambridge went on to found the Mullard Radio Astronomy Observatory near Cambridge in the 1950s. During the late 1960s and early 1970s, as computers became capable of handling the computationally intensive Fourier transform inversions required, they used aperture synthesis to create a'One-Mile' and a'5 km' effective
Nature is a British multidisciplinary scientific journal, first published on 4 November 1869. It is one of the most recognizable scientific journals in the world, was ranked the world's most cited scientific journal by the Science Edition of the 2010 Journal Citation Reports and is ascribed an impact factor of 40.137, making it one of the world's top academic journals. It is one of the few remaining academic journals that publishes original research across a wide range of scientific fields. Research scientists are the primary audience for the journal, but summaries and accompanying articles are intended to make many of the most important papers understandable to scientists in other fields and the educated public. Towards the front of each issue are editorials and feature articles on issues of general interest to scientists, including current affairs, science funding, scientific ethics and research breakthroughs. There are sections on books and short science fiction stories; the remainder of the journal consists of research papers, which are dense and technical.
Because of strict limits on the length of papers the printed text is a summary of the work in question with many details relegated to accompanying supplementary material on the journal's website. There are many fields of research in which important new advances and original research are published as either articles or letters in Nature; the papers that have been published in this journal are internationally acclaimed for maintaining high research standards. Fewer than 8% of submitted papers are accepted for publication. In 2007 Nature received the Prince of Asturias Award for Humanity; the enormous progress in science and mathematics during the 19th century was recorded in journals written in German or French, as well as in English. Britain underwent enormous technological and industrial changes and advances in the latter half of the 19th century. In English the most respected scientific journals of this time were the refereed journals of the Royal Society, which had published many of the great works from Isaac Newton, Michael Faraday through to early works from Charles Darwin.
In addition, during this period, the number of popular science periodicals doubled from the 1850s to the 1860s. According to the editors of these popular science magazines, the publications were designed to serve as "organs of science", in essence, a means of connecting the public to the scientific world. Nature, first created in 1869, was not the first magazine of its kind in Britain. One journal to precede Nature was Recreative Science: A Record and Remembrancer of Intellectual Observation, created in 1859, began as a natural history magazine and progressed to include more physical observational science and technical subjects and less natural history; the journal's name changed from its original title to Intellectual Observer: A Review of Natural History, Microscopic Research, Recreative Science and later to the Student and Intellectual Observer of Science and Art. While Recreative Science had attempted to include more physical sciences such as astronomy and archaeology, the Intellectual Observer broadened itself further to include literature and art as well.
Similar to Recreative Science was the scientific journal Popular Science Review, created in 1862, which covered different fields of science by creating subsections titled "Scientific Summary" or "Quarterly Retrospect", with book reviews and commentary on the latest scientific works and publications. Two other journals produced in England prior to the development of Nature were the Quarterly Journal of Science and Scientific Opinion, established in 1864 and 1868, respectively; the journal most related to Nature in its editorship and format was The Reader, created in 1864. These similar journals all failed; the Popular Science Review survived longest, lasting 20 years and ending its publication in 1881. The Quarterly Journal, after undergoing a number of editorial changes, ceased publication in 1885; the Reader terminated in 1867, Scientific Opinion lasted a mere 2 years, until June 1870. Not long after the conclusion of The Reader, a former editor, Norman Lockyer, decided to create a new scientific journal titled Nature, taking its name from a line by William Wordsworth: "To the solid ground of nature trusts the Mind that builds for aye".
First owned and published by Alexander Macmillan, Nature was similar to its predecessors in its attempt to "provide cultivated readers with an accessible forum for reading about advances in scientific knowledge." Janet Browne has proposed that "far more than any other science journal of the period, Nature was conceived and raised to serve polemic purpose." Many of the early editions of Nature consisted of articles written by members of a group that called itself the X Club, a group of scientists known for having liberal and somewhat controversial scientific beliefs relative to the time period. Initiated by Thomas Henry Huxley, the group consisted of such important scientists as Joseph Dalton Hooker, Herbert Spencer, John Tyndall, along with another five scientists and mathematicians, it was in part its scientific liberality that made Nature a longer-lasti