|
|
| Line 1: |
Line 1: |
| {{About|the mechanical device|the British peerage|Earl of Orrery}}
| | Hello. Allow me [http://Doeshivlooklikeme.org/ introduce] the writer. Her name is Refugia std home test Shryock. Managing individuals has been his std testing at home day job for a while. One of the extremely best things in the world for me is to do aerobics and now I'm trying to earn money with it. South Dakota is her birth place but she needs to transfer simply because of her family.<br><br>Also visit my web-site std testing at home, [http://www.dailymunch.com.au/node/3664296 please click the following page], |
| | |
| [[File:orrery small.jpg|thumb|A small orrery showing earth and the inner planets]]
| |
| | |
| An '''orrery''' is a mechanical [[Solar system model|model of the solar system]] device that illustrates the relative positions and motions of the [[planet]]s and [[natural satellite|moon]]s according to the [[heliocentric]] [[Scientific modelling|model]]. Though the Greeks had working [[planetaria]], the first orrery that was a planetarium of the modern era was produced in 1704, and one was presented to the [[Earl of Orrery]] — whence came the name. They are typically driven by a [[clockwork]] mechanism with a globe representing the [[Sun]] at the centre, and with a planet at the end of each of the arms.
| |
| | |
| == History ==
| |
| | |
| [[File:NAMA Machine d'Anticythère 1.jpg|thumb|[[Antikythera mechanism]] (main fragment), ca. 125 BC]]
| |
| [[File:Wright of Derby, The Orrery.jpg|thumb|''[[A Philosopher Lecturing on the Orrery]]'' (ca. 1766) by [[Joseph Wright of Derby]]]]
| |
| According to [[Cicero]], the Roman philosopher who was writing in the first century BC, [[Posidonius]] constructed a planetary model.
| |
| | |
| The [[Antikythera mechanism]], discovered in 1900 in a wreck off the Greek island of [[Antikythera]] and extensively studied, exhibited the [[diurnal motion]]s of the [[Sun]], [[Moon]], and the five known [[planet]]s. The Antikythera hand driven mechanism is now considered one of the first orreries, but for many decades was ignored as it was thought to be far too complex to be genuine.<ref name="HMSO">{{cite book|last=Calvert|first=H.R.|title=Astronomy: Globes Orreries and other Models|publisher=H.M.S.O|location=London|year=1967|accessdate=2011-06-10}}</ref> It was [[geocentric]] and used as a mechanical calculator designed to calculate astronomical positions.
| |
| | |
| As late as 1650, P. Schirleus built a geocentric [[planetarium]] with the Sun as a planet, and with [[Mercury (planet)|Mercury]] and [[Venus]] revolving around the Sun as its [[Natural satellite|moon]]s.<ref name="EE">{{cite book|last=Brewster|first=David|title=[[The Edinburgh Encyclopedia]] |publisher=William Blackwood et al.|location=Edinburgh|year=1830|volume=16|pages=624|chapter=Planetary Machines|url=http://books.google.com/books?id=q2tTt_NNr2YC&pg=PA646#v=onepage&q&f=false|accessdate=2011-06-08}}</ref>
| |
| | |
| In ''[[De revolutionibus orbium coelestium]]'', published in Nuremberg in 1543, [[Nicolaus Copernicus]] challenged the Western teaching of a [[Geocentric model|geocentric]] universe in which the Sun revolved daily around the [[Earth]]. He observed that some Greek philosophers had proposed a heliocentric universe. This simplified the apparent [[epicycle|epicyclic]] motions of the planets, making it feasible to represent the planets' paths as simple circles. This could be modeled by the use of gears. [[Tycho Brahe|Tycho Brahe's]] improved instruments made precise observations of the skies (1576–1601), and from these [[Johannes Kepler]] (1621) deduced that planets orbited the Sun in [[ellipse]]s. In 1687 [[Isaac Newton]] explained the cause of elliptic motion in his [[Newton's law of universal gravitation|theory of gravitation]].<ref name="Ronan">{{cite book|last=Ronan|first=Colin |title=The Practical Astronomer|publisher=Bloomsbury Books|location=London|date=1981,1992|pages=108–112|isbn=1-85471-047-8|accessdate=2011-06-08}}</ref>
| |
| | |
| [[Christiaan Huygens]] published details of a heliocentric planetary machine in 1703, which he built while resident in Paris between 1665 and 1681. He calculated the [[gear train]]s needed to represent a year of 365.242 days, and used that to produce the cycles of the principal planets.<ref name="EE"/> Clock makers [[George Graham (clockmaker)|George Graham]] and [[Thomas Tompion]] built the first modern orrery around 1704.<ref>Carlisle, Rodney (2004). ''Scientific American Inventions and Discoveries'', p. 189. John Wiley & Songs, Inc., New Jersey. ISBN 0-471-24410-4.</ref> Graham gave the first model, or its design, to the celebrated instrument maker John Rowley of London to make a copy for [[Prince Eugene of Savoy]]. Rowley was commissioned to make another copy for his patron [[Charles Boyle, 4th Earl of Orrery]], from which the device took its name.<ref>{{OED|orrery}}</ref> This model was presented to Charles' son John, later the [[John Boyle, 5th Earl of Cork|5th Earl of Cork and 5th Earl of Orrery]].
| |
| | |
| [[Joseph Wright of Derby|Joseph Wright]]'s painting ''[[A Philosopher Lecturing on the Orrery|A Philosopher giving a Lecture on the Orrery in which a lamp is put in place of the Sun]]'' (ca. 1766), which hangs in [[Derby Museum and Art Gallery]], depicts a group listening to a lecture by a [[natural philosophy|natural philosopher]]. The Sun in a brass orrery provides the only light in the room. The orrery depicted in the painting has rings, which give it an appearance similar to that of an [[armillary sphere]]. The demonstration was thereby able to depict [[eclipse]]s.<ref>{{cite web|url=http://www.search.revolutionaryplayers.org.uk/engine/resource/exhibition/standard/child.asp?txtKeywords=&lstContext=&lstResourceType=&lstExhibitionType=&chkPurchaseVisible=&txtDateFrom=&txtDateTo=&x1=&y1=&x2=&y2=&scale=&theme=&album=&resource=5230&viewpage=%2Fengine%2Fresource%2Fexhibition%2Fstandard%2Fdefault%2Easp&originator=&page=&records=&direction=&pointer=&text=&exhibition=1652&offset=0 |title=Revolutionary Players |publisher=Search.revolutionaryplayers.org.uk |date= |accessdate=2010-02-09}}</ref>
| |
| | |
| To put this in chronological context, in 1762 [[John Harrison]]'s [[marine chronometer]] first enabled accurate measurement of [[longitude]]. In 1766, astronomer [[Johann Daniel Titius]] first demonstrated that the mean distance of each planet from the Sun could be represented by the following progression:
| |
| | |
| <small>
| |
| :<math>
| |
| \frac{4+0}{10},\frac{4+3}{10},\frac{4+6}{10},\frac{4+12}{10},\frac{4+24}{10},\frac{4+48}{10},.....</math></small>
| |
| | |
| That is, 0.4, 0.7, 1.0, 1.6, 2.8, 5.2 ... The numbers refer to [[astronomical unit]]s, the mean distance between Sun and Earth, which is 1.496 x 10⁸ km (93 x 10⁶ miles). The Derby Orrery does not show mean distance, but demonstrated the relative planetary movements.
| |
| | |
| [[Eisinga Planetarium|Eisinga's Planetarium]] was built from 1774 to 1781 by Eise Eisinga in his home in [[Franeker]], in the Netherlands. It displays the planets across the width of a room's ceiling, and has been in operation almost continually since it was created.<ref>http://www.planetarium-friesland.nl/en</ref> This orrery is a planetarium in both senses of the word: a complex machine showing planetary orbits, and a theatre for depicting the planets' movement. Eisinga house was bought by the Dutch Royal family who gave him a pension.
| |
| [[File:Planetarium in Putnam Gallery 2, 2009-11-24.jpg|thumb|A 1766 Benjamin Martin Orrery, used at Harvard]]
| |
| | |
| In 1764, Benjamin Martin devised a new type of planetary model, in which the planets were carried on brass arms leading from a series of concentric or coaxial tubes. With this construction it was difficult to make the planets revolve, and to get the moons to turn around the planets. Martin suggested that the conventional orrery should consist of three parts: The planetarium where the planets revolved around the sun, the tellurian which showed the inclined axis of the earth and how it revolved around the sun, and the lunarium which showed the eccentric rotations of the moon around the earth. In one orrery, these three motions could be mounted on a common table, separately using the central spindle as a prime mover.<ref name="HMSO"/>
| |
| <!-- [[File:Planetaire Vatican.jpg|thumb|upright|Orrery ([[Vatican Museums]]).]]
| |
| [[File:Wilhelm Schickard.jpg|thumb|upright|Portrait of [[Wilhelm Schickard]] (1592-1635) holding a "hand planetarium" (orrery) of his own invention.]] -->
| |
| | |
| == Explanation ==
| |
| | |
| All orreries are ''planetariums'' or ''planetaria'' (alternative plural). The term '''orrery''' has only existed since 1714. A '''grand orrery''' is one that includes the [[outer planets]] known at the time of its construction. The word [[planetarium]], has been captured and now usually refers to hemispherical theatres in which images of the night sky are projected onto an overhead surface. Planetariums (orreries) can range widely in size from hand-held to room-sized. An orrery is used to demonstrate the motion of the planets, while a mechanical device used to predict [[eclipse]]s and [[Astronomical transit|transits]] is called an [[astrarium]].
| |
| | |
| An orrery should properly include the sun, earth and the (earth's) moon (plus optionally other planets.) A model that only includes the earth, its moon and the sun is called a [[tellurion]], and one which only includes the earth and moon a [[lunarium]]. A [[jovilabe]] is a model of [[Jupiter]] and its moons.<ref name="OU_S100_22">{{cite book|last=Pentz|first=M.J.|title=The Earth, Its Shape, Internal Structure and Composition|publisher=Open University Press|location=Bletchley|year=1971|volume=OU_S100_22|isbn=335 02034|accessdate=2011-06-08}}</ref>
| |
| | |
| {| class="wikitable"
| |
| | |
| !Planet!!Avg. Distance<br/> from Sun!!Diameter!!Mass!!Density!!No. of moons!!Orbital period (years)!!Inclination<br/> to ecliptic!!Axial tilt!!Rotational period (sidereal)
| |
| |-
| |
| | |
| |Mercury||0.39 [[astronomical unit|AU]]||0.38 Earth diameter||0.05 [[Earth mass]]||5.5 g/cm³||0||0.24||7.0||0||59 days
| |
| | |
| |-
| |
| | |
| |Venus||0.72||0.95||0.82||5.3||0||0.62||3.4||177||-243 days
| |
| | |
| |-
| |
| | |
| |Earth||1.00||1.00||1.00||5.5||1||1.00||0||23||23.9 hours
| |
| | |
| |-
| |
| | |
| |Mars||1.52||0.53||0.11||3.9||2||1.88||1.9||25||24.5 hours
| |
| | |
| |-
| |
| | |
| |
| |
| | |
| |-
| |
| | |
| |Jupiter||5.20||11.21||317.9||1.3||67||11.9||1.3||3||10 hours
| |
| | |
| |-
| |
| | |
| |Saturn||9.54||9.45||95.2||0.7||62||29.5||2.5||27||11 hours
| |
| | |
| |-
| |
| | |
| |Uranus||19.2||4.01||14.5||1.3||27||84||0.8||98||-17 hours
| |
| | |
| |-
| |
| | |
| |Neptune||30.1||3.88||17.1||1.6||14||165||1.8||28||16 hours
| |
| | |
| |-
| |
| | |
| |Pluto||39.4||0.18||0.002||2||5||248||17.1||122||-6.4 days
| |
| | |
| |-
| |
| | |
| |}
| |
| | |
| A planetarium will show the ''orbital period'' of each planet and the ''rotation rate'', as shown in the table above. A tellurion will show the [[Barycenter|earth with the moon]] revolving around the sun. It will use the angle of ''inclination of the equator'' from the table above to show how it rotates around its own axis. It will show the earth's moon, rotating around the earth.<ref name="Adler">{{cite web|url=http://64.107.216.64/research/collections/instruments/orreries.shtml|title=Adler Planetarium:Research& Collections|year=2010|publisher=Adler Planetarium.|accessdate=22 June 2011|location= 1300 South Lake Shore Drive • Chicago IL 60605}}</ref> A lunarium is designed to show the [[Orbit of the Moon|complex motions of the moon]] as it revolves around the earth.
| |
| | |
| Orreries are usually not built to [[scale model|scale]]. Some fixed [[Solar System model|Solar System scale models]] have been built and are often many kilometres in size. Human orreries, where humans move about as the planets, have also been constructed, but most are temporary. There is a permanent human orrery at [[Armagh Observatory]] in [[Northern Ireland]], which has the six ancient planets, [[Ceres (dwarf planet)|Ceres]], and comets [[Halley's Comet|Halley]] and [[Comet Encke|Encke]]. Uranus and beyond are also shown, but in a fairly limited way. Another is at Sky's the Limit Observatory and Nature Center in Twentynine Palms, CA. This is a true to scale (20 billion to one), true to position (accurate to within four days) human orrery. The first four planets are relatively close to one another, but the next four require a certain amount of hiking in order to visit them. This orrery is visible from space! Zoom in with Google Earth and you will see it.
| |
| | |
| A normal mechanical clock could be used to produce an extremely simple orrery with the Sun in the centre, [[Earth]] on the minute hand and [[Jupiter]] on the hour hand; Earth would make 12 revolutions around the Sun for every 1 revolution of Jupiter. Note however that Jupiter's actual year is 11.86 Earth years long, so this particular example would lose accuracy rapidly. A real orrery would be more accurate and include more planets, and would perhaps make the planets rotate as well.
| |
| | |
| ==Projection orreries==
| |
| | |
| Many planetariums (buildings) have a [[Planetarium projector|projection orrery]], which projects onto the dome of the planetarium a Sun with either dots or small images of the planets. These usually are limited to the planets from [[Mercury (planet)|Mercury]] to [[Saturn]], although some include [[Uranus]]. The light sources for the planets are projected onto mirrors which are geared to a motor which drives the images on the dome. Typically the Earth will circle the Sun in one minute, while the other planets will complete an orbit in time periods proportional to their actual motion. Thus Venus, which takes 224.7 days to orbit the Sun, will take 37 seconds to complete an orbit on an orrery, and Jupiter will take 11 minutes, 52 seconds.
| |
| | |
| Some planetariums have taken advantage of this to use orreries to simulate planets and their moons. Thus Mercury orbits the Sun in 0.24 of an Earth year, while [[Phobos (moon)|Phobos]] and [[Deimos (moon)|Deimos]] orbit [[Mars]] in a similar 4:1 time ratio. Planetarium operators wishing to show this have placed a red cap on the Sun (to make it resemble Mars) and turned off all the planets but Mercury and Earth. Similar tricks can be used to show [[Pluto]] and its five moons.
| |
| | |
| ==Notable orreries==
| |
| | |
| Shoemaker [[John Fulton (instrument maker)]] of Fenwick, Ayrshire, built three between 1823 and 1833. The last is in Glasgow's [[Kelvingrove Art Gallery and Museum]].
| |
| | |
| The [[Eisinga Planetarium|Franeker Planetarium]] built by a [[Carding|wool carder]] called Eise Eisinga in his own living room, in the small city of [[Franeker]] in [[Friesland]], is in fact an orrery. It was constructed between 1774 to 1781. The "face" of the model looks down from the ceiling of a room, with most of the mechanical works in the space above the ceiling. It is driven by a pendulum clock, which has 9 weights or ponds. The planets move around the model in real time.<ref name="Sixma">{{cite journal|last=Sixma|first=H|date=November 1934|title=The Franeker Planetarium|journal=Popular Astronomy|publisher=SAO/NASA ADS|volume=XLII|issue=9|pages=489–495|url=http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?bibcode=1934PA.....42..489S&db_key=AST&page_ind=0&plate_select=NO&data_type=GIF&type=SCREEN_GIF&classic=YES|accessdate=2011-06-22}}</ref>
| |
| | |
| An innovative concept is to have people play the role of the moving planets and other Solar System objects. Such a model, called a human orrery, has been laid out with precision at the [[Armagh Observatory]].
| |
| | |
| ===Meccano Planetaria===
| |
| | |
| The first Meccano Orrery was described in June 1918 [[Meccano]] Manual, though it is the last quarter of the 20th Century that Alan Partridge, John Nuttall, Pat Briggs and Michael Whiting have experimented with the limitations and possibilities of this medium. There are six methods of building orreries:<ref name="Meccano">{{cite journal|last=Whiting|first=Michael|year=2007|title=Orrery Developments:The Use of Meccano in Constructing Planetaria|journal=Bulletin of the Scientific Society|issue= 94|accessdate=2011-06-08}}</ref>
| |
| | |
| *Telescopic concentric tubing, though the tubing is not a Meccano part. For a full 9 planet system, 18 concentric tubes and 19 geared motions are needed
| |
| *Nested hollow turntables with internal gearing. A 1984 Jovilabe showing Jupiter and the 14 then known moons required 14 turntables and 324 gears; it is accurate to within 0.01%
| |
| *Fixed central rod, with top drive and sun and planet gearing. In this method, the sun drives the first planet and this then drives the second and so on. The errors are thus cumulative, but non-Meccano gearing can keep this within 0.02%
| |
| *Fixed central tube, with bottom drive and sun and planet gearing. This removes the need for an overhead gantry, improving the appearance
| |
| *Two component epicyclic gearing.
| |
| *Fixed Central Rod, Epicyclic gearing, top drive by 'by-pass gearing' from below.
| |
| | |
| ==In popular media==
| |
| | |
| * An orrery appears in Aughra's observatory in ''[[The Dark Crystal]]''.
| |
| * A large orrery is a key feature in the climactic scene of the film ''[[Lara Croft: Tomb Raider]]'' (2001).
| |
| * An orrery is used to determine when total eclipses occur in ''[[Pitch Black (film)|Pitch Black]]''.
| |
| * The Orrery is an artificial construct consisting of life-sized planets and a sun in ''[[Green Lantern: New Guardians]]''.<ref>''New Guardians'' #4-6 (Dec 2011 - Feb 2012)</ref>
| |
| * A pair of large orreries appear as architectural features and plot elements in John Crowley's novel [[Little, Big]].
| |
| | |
| ==See also==
| |
| | |
| *[[Apparent retrograde motion]]
| |
| *[[Astrarium]]
| |
| *[[Astrolabe]]
| |
| *[[Astronomical clock]]
| |
| *[[Clockwork universe]]
| |
| *[[Ephemeris]]
| |
| *[[Equatorium]]
| |
| *[[Eratosthenes]]
| |
| *[[Orbit of the Moon]]
| |
| *[[Stability of the Solar System]]
| |
| *[[Tellurion]]
| |
| *[[Torquetum]]
| |
| | |
| ==References==
| |
| | |
| {{Reflist}}
| |
| | |
| ==External links==
| |
| | |
| {{Commons category|Orreries}}
| |
| | |
| * [http://space.jpl.nasa.gov/ JPL Solar System Simulator]
| |
| * [http://star.arm.ac.uk/orrery/ Armagh Observatory Human Orrery]
| |
| * [http://www.longnow.org/projects/clock/orrery/ Long Now Foundation Orrery]
| |
| * [http://www.library.upenn.edu/exhibits/pennhistory/orrery/orrery.html University of Pennsylvania Orrery]
| |
| | |
| [[Category:Historical scientific instruments]]
| |
| [[Category:Astronomical instruments]]
| |
| [[Category:Solar System models]]
| |
| [[Category:Scale modeling]]
| |