Point source
A point source is a single identifiable localised source of something. A point source has negligible extent. Sources are called point sources because in mathematical modeling, these sources can be approximated as a mathematical point to simplify analysis; the actual source need not be physically small, if its size is negligible relative to other length scales in the problem. For example, in astronomy, stars are treated as point sources though they are in actuality much larger than the Earth. In three dimensions, the density of something leaving a point source decreases in proportion to the inverse square of the distance from the source, if the distribution is isotropic, there is no absorption or other loss. In mathematics, a point source is a singularity from which flow is emanating. Although singularities such as this do not exist in the observable universe, mathematical point sources are used as approximations to reality in physics and other fields. A source of light can be considered a point source if the resolution of the imaging instrument is too low to resolve the source's apparent size.
There are two sources of light. A point source, an extended source. Mathematically an object may be considered a point source if its angular size, θ, is much smaller than the resolving power of the telescope: θ << λ / D, where λ is the wavelength of light and D is the telescope diameter. Examples: Light from a distant star seen through a small telescope Light passing through a pinhole or other small aperture, viewed from a distance much greater than the size of the hole Light from a street light in a large-scale study of light pollution or street illumination Radio wave sources which are smaller than one radio wavelength are generally treated as point sources. Radio emissions generated by a fixed electrical circuit are polarized, producing anisotropic radiation. If the propagating medium is lossless, the radiant power in the radio waves at a given distance will still vary as the inverse square of the distance if the angle remains constant to the source polarization. Gamma ray and X-ray sources may be treated as a point source.
Radiological contamination and nuclear sources are point sources. This has significance in radiation protection. Examples: Radio antennas are smaller than one wavelength though they are many metres across Pulsars are treated as point sources when observed using radio telescopes In nuclear physics, a "hot spot" is a point source of radiation Sound is an oscillating pressure wave; as the pressure oscillates up and down, an audio point source acts in turn as a fluid point source and a fluid point sink. Examples: Seismic vibration from a localised seismic experiment searching for oil Noise pollution from a jet engine in a large-scale study of noise pollution A loudspeaker may be considered as a point source in a study of the acoustics of airport announcements Point sources are used as a means of calibrating ionizing radiation instruments, they are a sealed capsule and are most used for gamma, x-ray and beta measuring instruments. In vacuum, heat escapes as radiation isotropically. If the source remains stationary in a compressible fluid such as air, flow patterns can form around the source due to convection, leading to an anisotropic pattern of heat loss.
The most common form of anisotropy is the formation of a thermal plume above the heat source. Examples: Geological hotspots on the surface of the Earth which lie at the tops of thermal plumes rising from deep inside the Earth Plumes of heat studied in thermal pollution tracking. Fluid point sources are used in fluid dynamics and aerodynamics. A point source of fluid is the inverse of a fluid point sink. Whereas fluid sinks exhibit complex changing behaviour such as is seen in vortices, fluid sources produce simple flow patterns, with stationary isotropic point sources generating an expanding sphere of new fluid. If the fluid is moving a plume is generated from the point source. Examples: Air pollution from a power plant flue gas stack in a large scale analysis of air pollution Water pollution from an oil refinery wastewater discharge outlet in a large scale analysis of water pollution Gas escaping from a pressurised pipe in a laboratory Smoke is released from point sources in a wind tunnel in order to create a plume of smoke which highlights the flow of the wind over an object Smoke from a localised chemical fire can be blown in the wind to form a plume of pollution Sources of various types of pollution are considered as point sources in large-scale studies of pollution.
Line source Dirac delta function
2MASS J04414489+2301513
2MASS J04414489+2301513 is a young brown dwarf 470 light years away with an orbiting companion about 5–10 times the mass of Jupiter. The mass of the primary brown dwarf is 20 times the mass of Jupiter and its age is one million years, it is not clear whether this companion object is a planet. The companion is large with respect to its parent and must have formed within 1 million years or so; this seems to be too big and too fast to form like a regular planet from a disk around the central object. 2MASS J04414489+2301513 has another companion, 2MASS J04414565+2301580, another binary star. At a separation of 0.23 arcseconds to the northeast, it has a similar proper motion to 2M J044144 and is physically associated with the system. The primary component has a spectral type of M4.5 and a red apparent magnitude of 14.2. Both components seem to be accreting mass from their stellar disks, as shown by their emission lines; the four stars have a total mass of only 26% of the Sun, making it the quadruple star system with the lowest mass known.
2MASS 2M1207 HR 8799 Jean Schneider. "Notes for star 2M J044144". Extrasolar Planets Encyclopaedia. Archived from the original on 19 January 2012. Retrieved 30 September 2011
University of Massachusetts Amherst
The University of Massachusetts Amherst is a public research and land-grant university in Amherst, Massachusetts. It is the flagship campus of the University of Massachusetts system. UMass Amherst has an annual enrollment of 1,300 faculty members and more than 30,000 students and was ranked 27th best public university by U. S. News Report in 2018 in the national universities category; the university offers academic degrees in 77 master's and 48 doctoral programs. Programs are coordinated in colleges; the main campus is situated north of downtown Amherst. In 2012, U. S. News and World Report ranked Amherst among the Top 10 Great College Towns in America, it is a member of the Five College Consortium. The University of Massachusetts Amherst is categorized as a Research University with Highest research activity by the Carnegie Foundation for the Advancement of Teaching. In fiscal year 2014, UMass Amherst had research expenditures exceeding $200 million. UMass Amherst sports teams are called the Minutemen and Minutewomen, the colors being maroon and white.
All teams participate in NCAA Division I. The university is a member of the Atlantic 10 Conference, while playing ice hockey in Hockey East and football as an FBS Independent; the university was founded in 1863 under the provisions of the Federal Morrill Land-Grant Colleges Act to provide instruction to Massachusetts citizens in "agricultural and military arts." Accordingly, the university was named the Massachusetts Agricultural College, popularly referred to as "Mass Aggie" or "M. A. C." In 1867, the college had yet to admit any students, been through two Presidents, had still not completed any college buildings. In that year, William S. Clark was appointed Professor of Botany, he appointed a faculty, completed the construction plan, and, in the fall of 1867, admitted the first class of 50 students. Clark became the first president to serve longterm after the schools opening and is regarded the primary founding father of the college. Of the school's founding figures, there are a traditional "founding four"- Clark, Levi Stockbridge, Charles Goessmann, Henry Goodell, described as "the botanist, the farmer, the chemist, the man of letters."The original buildings consisted of Old South College, North College, the Chemistry Laboratory known as College Hall, the Boarding House, the Botanic Museum and the Durfee Plant House.
Although enrollment was slow during the 1870s, the fledgling college built momentum under the leadership of President Henry Hill Goodell. In the 1880s, Goodell implemented an expansion plan, adding the College Drill Hall in 1883, the Old Chapel Library in 1885, the East and West Experiment Stations in 1886 and 1890; the Campus Pond, now the central focus of the University Campus, was created in 1893 by damming a small brook. The early 20th century saw great expansion in the scope of the curriculum; the first female student was admitted in 1875 on a part-time basis and the first full-time female student was admitted in 1892. In 1903, Draper Hall was constructed for the dual purpose of a dining female housing; the first female students graduated with the class of 1905. The first dedicated female dormitory, the Abigail Adams House was built in 1920. By the start of the 20th century, the college was thriving and expanded its curriculum to include the liberal arts; the Education curriculum was established in 1907.
In recognition of the higher enrollment and broader curriculum, the college was renamed Massachusetts State College in 1931. Following World War II, the G. I. Bill, facilitating financial aid for veterans, led to an explosion of applicants; the college population soared and Presidents Hugh Potter Baker and Ralph Van Meter labored to push through major construction projects in the 1940s and 1950s with regard to dormitories. Accordingly, the name of the college was changed in 1947 to the "University of Massachusetts." By the 1970s, the University continued to grow and gave rise to a shuttle bus service on campus as well as many other architectural additions. Du Bois Library, the Fine Arts Center. Over the course of the next two decades, the John W. Lederle Graduate Research Center and the Conte National Polymer Research Center were built and UMass Amherst emerged as a major research facility; the Robsham Memorial Center for Visitors welcomed thousands of guests to campus after its dedication in 1989.
For athletic and other large events, the Mullins Center was opened in 1993, hosting capacity crowds as the Minutemen basketball team ranked at number one for many weeks in the mid-1990s, reached the Final Four in 1996. UMass Amherst entered. In 2003, for the first time, the Massachusetts State Legislature designated UMass Amherst as a Research Univ
NASA
The National Aeronautics and Space Administration is an independent agency of the United States Federal Government responsible for the civilian space program, as well as aeronautics and aerospace research. NASA was established in 1958; the new agency was to have a distinctly civilian orientation, encouraging peaceful applications in space science. Since its establishment, most US space exploration efforts have been led by NASA, including the Apollo Moon landing missions, the Skylab space station, the Space Shuttle. NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle, the Space Launch System and Commercial Crew vehicles; the agency is responsible for the Launch Services Program which provides oversight of launch operations and countdown management for unmanned NASA launches. NASA science is focused on better understanding Earth through the Earth Observing System. From 1946, the National Advisory Committee for Aeronautics had been experimenting with rocket planes such as the supersonic Bell X-1.
In the early 1950s, there was challenge to launch an artificial satellite for the International Geophysical Year. An effort for this was the American Project Vanguard. After the Soviet launch of the world's first artificial satellite on October 4, 1957, the attention of the United States turned toward its own fledgling space efforts; the US Congress, alarmed by the perceived threat to national security and technological leadership, urged immediate and swift action. On January 12, 1958, NACA organized a "Special Committee on Space Technology", headed by Guyford Stever. On January 14, 1958, NACA Director Hugh Dryden published "A National Research Program for Space Technology" stating: It is of great urgency and importance to our country both from consideration of our prestige as a nation as well as military necessity that this challenge be met by an energetic program of research and development for the conquest of space... It is accordingly proposed that the scientific research be the responsibility of a national civilian agency...
NACA is capable, by rapid extension and expansion of its effort, of providing leadership in space technology. While this new federal agency would conduct all non-military space activity, the Advanced Research Projects Agency was created in February 1958 to develop space technology for military application. On July 29, 1958, Eisenhower signed the National Aeronautics and Space Act, establishing NASA; when it began operations on October 1, 1958, NASA absorbed the 43-year-old NACA intact. A NASA seal was approved by President Eisenhower in 1959. Elements of the Army Ballistic Missile Agency and the United States Naval Research Laboratory were incorporated into NASA. A significant contributor to NASA's entry into the Space Race with the Soviet Union was the technology from the German rocket program led by Wernher von Braun, now working for the Army Ballistic Missile Agency, which in turn incorporated the technology of American scientist Robert Goddard's earlier works. Earlier research efforts within the US Air Force and many of ARPA's early space programs were transferred to NASA.
In December 1958, NASA gained control of the Jet Propulsion Laboratory, a contractor facility operated by the California Institute of Technology. The agency's leader, NASA's administrator, is nominated by the President of the United States subject to approval of the US Senate, reports to him or her and serves as senior space science advisor. Though space exploration is ostensibly non-partisan, the appointee is associated with the President's political party, a new administrator is chosen when the Presidency changes parties; the only exceptions to this have been: Democrat Thomas O. Paine, acting administrator under Democrat Lyndon B. Johnson, stayed on while Republican Richard Nixon tried but failed to get one of his own choices to accept the job. Paine was confirmed by the Senate in March 1969 and served through September 1970. Republican James C. Fletcher, appointed by Nixon and confirmed in April 1971, stayed through May 1977 into the term of Democrat Jimmy Carter. Daniel Goldin was appointed by Republican George H. W. Bush and stayed through the entire administration of Democrat Bill Clinton.
Robert M. Lightfoot, Jr. associate administrator under Democrat Barack Obama, was kept on as acting administrator by Republican Donald Trump until Trump's own choice Jim Bridenstine, was confirmed in April 2018. Though the agency is independent, the survival or discontinuation of projects can depend directly on the will of the President; the first administrator was Dr. T. Keith Glennan appointed by Republican President Dwight D. Eisenhower. During his term he brought together the disparate projects in American space development research; the second administrator, James E. Webb, appointed by President John F. Kennedy, was a Democrat who first publicly served under President Harry S. Truman. In order to implement the Apollo program to achieve Kennedy's Moon la
Nebula
A nebula is an interstellar cloud of dust, hydrogen and other ionized gases. The term was used to describe any diffuse astronomical object, including galaxies beyond the Milky Way; the Andromeda Galaxy, for instance, was once referred to as the Andromeda Nebula before the true nature of galaxies was confirmed in the early 20th century by Vesto Slipher, Edwin Hubble and others. Most nebulae are of vast size. A nebula, visible to the human eye from Earth would appear larger, but no brighter, from close by; the Orion Nebula, the brightest nebula in the sky and occupying an area twice the diameter of the full Moon, can be viewed with the naked eye but was missed by early astronomers. Although denser than the space surrounding them, most nebulae are far less dense than any vacuum created on Earth – a nebular cloud the size of the Earth would have a total mass of only a few kilograms. Many nebulae are visible due to fluorescence caused by embedded hot stars, while others are so diffuse they can only be detected with long exposures and special filters.
Some nebulae are variably illuminated by T Tauri variable stars. Nebulae are star-forming regions, such as in the "Pillars of Creation" in the Eagle Nebula. In these regions the formations of gas and other materials "clump" together to form denser regions, which attract further matter, will become dense enough to form stars; the remaining material is believed to form planets and other planetary system objects. Around 150 AD, Claudius Ptolemaeus recorded, in books VII–VIII of his Almagest, five stars that appeared nebulous, he noted a region of nebulosity between the constellations Ursa Major and Leo, not associated with any star. The first true nebula, as distinct from a star cluster, was mentioned by the Persian astronomer Abd al-Rahman al-Sufi, in his Book of Fixed Stars, he noted "a little cloud". He cataloged the Omicron Velorum star cluster as a "nebulous star" and other nebulous objects, such as Brocchi's Cluster; the supernova that created the Crab Nebula, the SN 1054, was observed by Arabic and Chinese astronomers in 1054.
In 1610, Nicolas-Claude Fabri de Peiresc discovered the Orion Nebula using a telescope. This nebula was observed by Johann Baptist Cysat in 1618. However, the first detailed study of the Orion Nebula was not performed until 1659, by Christiaan Huygens, who believed he was the first person to discover this nebulosity. In 1715, Edmund Halley published a list of six nebulae; this number increased during the century, with Jean-Philippe de Cheseaux compiling a list of 20 in 1746. From 1751 to 1753, Nicolas Louis de Lacaille cataloged 42 nebulae from the Cape of Good Hope, most of which were unknown. Charles Messier compiled a catalog of 103 "nebulae" by 1781; the number of nebulae was greatly increased by the efforts of William Herschel and his sister Caroline Herschel. Their Catalogue of One Thousand New Nebulae and Clusters of Stars was published in 1786. A second catalog of a thousand was published in 1789 and the third and final catalog of 510 appeared in 1802. During much of their work, William Herschel believed that these nebulae were unresolved clusters of stars.
In 1790, however, he discovered a star surrounded by nebulosity and concluded that this was a true nebulosity, rather than a more distant cluster. Beginning in 1864, William Huggins examined the spectra of about 70 nebulae, he found that a third of them had the emission spectrum of a gas. The rest thus were thought to consist of a mass of stars. A third category was added in 1912 when Vesto Slipher showed that the spectrum of the nebula that surrounded the star Merope matched the spectra of the Pleiades open cluster, thus the nebula radiates by reflected star light. About 1923, following the Great Debate, it had become clear that many "nebulae" were in fact galaxies far from our own. Slipher and Edwin Hubble continued to collect the spectra from many different nebulae, finding 29 that showed emission spectra and 33 that had the continuous spectra of star light. In 1932, Hubble announced that nearly all nebula are associated with stars, their illumination comes from star light, he discovered that the emission spectrum nebulae are nearly always associated with stars having spectral classifications of B or hotter, while nebulae with continuous spectra appear with cooler stars.
Both Hubble and Henry Norris Russell concluded that the nebulae surrounding the hotter stars are transfomed in some manner. There are a variety of formation mechanisms for the different types of nebulae; some nebulae form from gas, in the interstellar medium while others are produced by stars. Examples of the former case are giant molecular clouds, the coldest, densest phase of interstellar gas, which can form by the cooling and condensation of more diffuse gas. Examples of the latter case are planetary nebulae formed from material shed by a star in late stages of its stellar evolution. Star-forming regions are a class of emission nebula associated with giant molecular clouds; these form as a molecular cloud collapses under its own weight. Massive stars may form in the center, their ultraviolet radiation ionizes the surrounding gas, making it visible at optical wavelengths; the region of ionized hydrogen surrounding th
Apparent magnitude
The apparent magnitude of an astronomical object is a number, a measure of its brightness as seen by an observer on Earth. The magnitude scale is logarithmic. A difference of 1 in magnitude corresponds to a change in brightness by a factor of 5√100, or about 2.512. The brighter an object appears, the lower its magnitude value, with the brightest astronomical objects having negative apparent magnitudes: for example Sirius at −1.46. The measurement of apparent magnitudes or brightnesses of celestial objects is known as photometry. Apparent magnitudes are used to quantify the brightness of sources at ultraviolet and infrared wavelengths. An apparent magnitude is measured in a specific passband corresponding to some photometric system such as the UBV system. In standard astronomical notation, an apparent magnitude in the V filter band would be denoted either as mV or simply as V, as in "mV = 15" or "V = 15" to describe a 15th-magnitude object; the scale used to indicate magnitude originates in the Hellenistic practice of dividing stars visible to the naked eye into six magnitudes.
The brightest stars in the night sky were said to be of first magnitude, whereas the faintest were of sixth magnitude, the limit of human visual perception. Each grade of magnitude was considered twice the brightness of the following grade, although that ratio was subjective as no photodetectors existed; this rather crude scale for the brightness of stars was popularized by Ptolemy in his Almagest and is believed to have originated with Hipparchus. In 1856, Norman Robert Pogson formalized the system by defining a first magnitude star as a star, 100 times as bright as a sixth-magnitude star, thereby establishing the logarithmic scale still in use today; this implies that a star of magnitude m is about 2.512 times as bright as a star of magnitude m + 1. This figure, the fifth root of 100, became known as Pogson's Ratio; the zero point of Pogson's scale was defined by assigning Polaris a magnitude of 2. Astronomers discovered that Polaris is variable, so they switched to Vega as the standard reference star, assigning the brightness of Vega as the definition of zero magnitude at any specified wavelength.
Apart from small corrections, the brightness of Vega still serves as the definition of zero magnitude for visible and near infrared wavelengths, where its spectral energy distribution approximates that of a black body for a temperature of 11000 K. However, with the advent of infrared astronomy it was revealed that Vega's radiation includes an Infrared excess due to a circumstellar disk consisting of dust at warm temperatures. At shorter wavelengths, there is negligible emission from dust at these temperatures. However, in order to properly extend the magnitude scale further into the infrared, this peculiarity of Vega should not affect the definition of the magnitude scale. Therefore, the magnitude scale was extrapolated to all wavelengths on the basis of the black-body radiation curve for an ideal stellar surface at 11000 K uncontaminated by circumstellar radiation. On this basis the spectral irradiance for the zero magnitude point, as a function of wavelength, can be computed. Small deviations are specified between systems using measurement apparatuses developed independently so that data obtained by different astronomers can be properly compared, but of greater practical importance is the definition of magnitude not at a single wavelength but applying to the response of standard spectral filters used in photometry over various wavelength bands.
With the modern magnitude systems, brightness over a wide range is specified according to the logarithmic definition detailed below, using this zero reference. In practice such apparent magnitudes do not exceed 30; the brightness of Vega is exceeded by four stars in the night sky at visible wavelengths as well as the bright planets Venus and Jupiter, these must be described by negative magnitudes. For example, the brightest star of the celestial sphere, has an apparent magnitude of −1.4 in the visible. Negative magnitudes for other bright astronomical objects can be found in the table below. Astronomers have developed other photometric zeropoint systems as alternatives to the Vega system; the most used is the AB magnitude system, in which photometric zeropoints are based on a hypothetical reference spectrum having constant flux per unit frequency interval, rather than using a stellar spectrum or blackbody curve as the reference. The AB magnitude zeropoint is defined such that an object's AB and Vega-based magnitudes will be equal in the V filter band.
As the amount of light received by a telescope is reduced by transmission through the Earth's atmosphere, any measurement of apparent magnitude is corrected for what it would have been as seen from above the atmosphere. The dimmer an object appears, the higher the numerical value given to its apparent magnitude, with a difference of 5 magnitudes corresponding to a brightness factor of 100. Therefore, the apparent magnitude m, in the spectral band x, would be given by m x = − 5 log 100 , more expressed in terms of common logarithms as m x
Asteroid
Asteroids are minor planets of the inner Solar System. Larger asteroids have been called planetoids; these terms have been applied to any astronomical object orbiting the Sun that did not resemble a planet-like disc and was not observed to have characteristics of an active comet such as a tail. As minor planets in the outer Solar System were discovered they were found to have volatile-rich surfaces similar to comets; as a result, they were distinguished from objects found in the main asteroid belt. In this article, the term "asteroid" refers to the minor planets of the inner Solar System including those co-orbital with Jupiter. There exist millions of asteroids, many thought to be the shattered remnants of planetesimals, bodies within the young Sun's solar nebula that never grew large enough to become planets; the vast majority of known asteroids orbit within the main asteroid belt located between the orbits of Mars and Jupiter, or are co-orbital with Jupiter. However, other orbital families exist with significant populations, including the near-Earth objects.
Individual asteroids are classified by their characteristic spectra, with the majority falling into three main groups: C-type, M-type, S-type. These were named after and are identified with carbon-rich and silicate compositions, respectively; the sizes of asteroids varies greatly. Asteroids are differentiated from meteoroids. In the case of comets, the difference is one of composition: while asteroids are composed of mineral and rock, comets are composed of dust and ice. Furthermore, asteroids formed closer to the sun; the difference between asteroids and meteoroids is one of size: meteoroids have a diameter of one meter or less, whereas asteroids have a diameter of greater than one meter. Meteoroids can be composed of either cometary or asteroidal materials. Only one asteroid, 4 Vesta, which has a reflective surface, is visible to the naked eye, this only in dark skies when it is favorably positioned. Small asteroids passing close to Earth may be visible to the naked eye for a short time; as of October 2017, the Minor Planet Center had data on 745,000 objects in the inner and outer Solar System, of which 504,000 had enough information to be given numbered designations.
The United Nations declared 30 June as International Asteroid Day to educate the public about asteroids. The date of International Asteroid Day commemorates the anniversary of the Tunguska asteroid impact over Siberia, Russian Federation, on 30 June 1908. In April 2018, the B612 Foundation reported "It's 100 percent certain we'll be hit, but we're not 100 percent sure when." In 2018, physicist Stephen Hawking, in his final book Brief Answers to the Big Questions, considered an asteroid collision to be the biggest threat to the planet. In June 2018, the US National Science and Technology Council warned that America is unprepared for an asteroid impact event, has developed and released the "National Near-Earth Object Preparedness Strategy Action Plan" to better prepare. According to expert testimony in the United States Congress in 2013, NASA would require at least five years of preparation before a mission to intercept an asteroid could be launched; the first asteroid to be discovered, was considered to be a new planet.
This was followed by the discovery of other similar bodies, with the equipment of the time, appeared to be points of light, like stars, showing little or no planetary disc, though distinguishable from stars due to their apparent motions. This prompted the astronomer Sir William Herschel to propose the term "asteroid", coined in Greek as ἀστεροειδής, or asteroeidēs, meaning'star-like, star-shaped', derived from the Ancient Greek ἀστήρ astēr'star, planet'. In the early second half of the nineteenth century, the terms "asteroid" and "planet" were still used interchangeably. Overview of discovery timeline: 10 by 1849 1 Ceres, 1801 2 Pallas – 1802 3 Juno – 1804 4 Vesta – 1807 5 Astraea – 1845 in 1846, planet Neptune was discovered 6 Hebe – July 1847 7 Iris – August 1847 8 Flora – October 1847 9 Metis – 25 April 1848 10 Hygiea – 12 April 1849 tenth asteroid discovered 100 asteroids by 1868 1,000 by 1921 10,000 by 1989 100,000 by 2005 ~700,000 by 2015 Asteroid discovery methods have improved over the past two centuries.
In the last years of the 18th century, Baron Franz Xaver von Zach organized a group of 24 astronomers to search the sky for the missing planet predicted at about 2.8 AU from the Sun by the Titius-Bode law because of the discovery, by Sir William Herschel in 1781, of the planet Uranus at the distance predicted by the law. This task required that hand-drawn sky charts be prepared for all stars in the zodiacal band down to an agreed-upon limit of faintness. On subsequent nights, the sky would be charted again and any moving object would be spotted; the expected motion of the missing planet was about 30 seconds of arc per hour discernible by observers. The first object, was not discovered by a member of the group, but rather by accident in 1801 by Giuseppe Piazzi, director of the observatory of Palermo in Sicily, he discovered a new star-like object in Taurus and followed the displacement of this object during several nights. That year, Carl Friedrich Gauss used these observations to calculate the orbit of this unknown object, found to be between the planets Mars and Jupiter.
Piazzi named it after Ceres, the Roman goddess of agriculture. Three other asteroids (2 Pallas, 3 Juno, 4 Ves
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