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74-402: Ole Christensen Rømer ( Danish: [ˈoːlə ˈʁœˀmɐ] ; 25 September 1644 – 19 September 1710) was a Danish astronomer who, in 1676, first demonstrated that light travels at a finite speed. Rømer also invented the modern thermometer showing the temperature between two fixed points, namely the points at which water respectively boils and freezes. Rømer made his discovery regarding
148-513: A eutectic system , which stabilizes its temperature automatically: 0 °F was defined to be that stable temperature. A second point, 96 degrees, was approximately the human body's temperature. A third point, 32 degrees, was marked as being the temperature of ice and water "without the aforementioned salts". According to a German story, Fahrenheit actually chose the lowest air temperature measured in his hometown Danzig (Gdańsk, Poland ) in winter 1708–09 as 0 °F, and only later had
222-427: A nationality and reserve the word "ethnic" for the description of recent immigrants , sometimes referred to as "new Danes". The contemporary Danish national identity is based on the idea of "Danishness", which is founded on principles formed through historical cultural connections and is typically not based on ethnic heritage. Denmark has been inhabited by various Germanic peoples since ancient times, including
296-641: A concept, det danske folk (the Danish people) played an important role in 19th-century ethnic nationalism and refers to self-identification rather than a legal status. Use of the term is most often restricted to a historical context; the historic German-Danish struggle regarding the status of the Duchy of Schleswig vis-à-vis a Danish nation-state . It describes people of Danish nationality , both in Denmark and elsewhere–most importantly, ethnic Danes in both Denmark proper and
370-497: A gentleman under Denmark. On 7 December 2016, a Google Doodle was dedicated to Rømer. [REDACTED] Media related to Ole Rømer at Wikimedia Commons Danes Danes ( Danish : danskere , pronounced [ˈtænskɐɐ] ), or Danish people , are an ethnic group and nationality native to Denmark and a modern nation identified with the country of Denmark. This connection may be ancestral, legal, historical, or cultural. Danes generally regard themselves as
444-545: A good relationship with the archbishop of Bremen , at that time the archbishop of all Scandinavia . Over the next centuries, the Danish empire expanded throughout the southern Baltic coast. Under the 14th century king Olaf II , Denmark acquired control of the Kingdom of Norway , which included the territories of Norway , Iceland and the Faroese Islands . Olaf's mother, Margrethe I , united Norway, Sweden and Denmark into
518-578: A modified version of Rømer's scale that eventually evolved into the Fahrenheit scale still popular in the United States and a few other countries. Rømer also established navigation schools in several Danish cities. In 1705, Rømer was made the second Chief of the Copenhagen Police , a position he kept until his death in 1710. As one of his first acts, he fired the entire force, being convinced that
592-407: A part of the museum Kroppedal at the same location. In Denmark, Ole Rømer has been honoured in various ways through the ages. He has been portrayed on bank notes, the eponymous Ole Rømer's Hill [ da ] is named after him, as are streets in both Aarhus and Copenhagen ( Ole Rømers Gade and Rømersgade [ da ] respectively). Aarhus University's astronomical observatory
666-508: A period of several months, while in Paris Giovanni Domenico Cassini observed the same eclipses. By comparing the times of the eclipses, the difference in longitude of Paris to Uraniborg was calculated. Cassini had observed the moons of Jupiter between 1666 and 1668, and discovered discrepancies in his measurements that, at first, he attributed to light having a finite speed. In 1672 Rømer went to Paris and continued observing
740-479: A prize for a method to determine the longitude of a ship out of sight of land, and Galileo proposed a method of establishing the time of day, and thus longitude, based on the times of the eclipses of the moons of Jupiter , in essence using the Jovian system as a cosmic clock; this method was not significantly improved until accurate mechanical clocks were developed in the eighteenth century. Galileo proposed this method to
814-467: A supplementary unit. Most British people use Celsius. However, the use of Fahrenheit still may appear at times alongside degrees Celsius in the print media with no standard convention for when the measurement is included. For example, The Times has an all-metric daily weather page but includes a Celsius-to-Fahrenheit conversion table. Some UK tabloids have adopted a tendency of using Fahrenheit for mid to high temperatures. It has been suggested that
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#1732902437227888-408: A value for the speed of light. However, many others calculated a speed from his data, the first being Christiaan Huygens ; after corresponding with Rømer and eliciting more data, Huygens deduced that light travelled 16 + 2 ⁄ 3 Earth diameters per second, which is approximately 212,000 km/s. Rømer's view that the velocity of light was finite was not fully accepted until measurements of
962-539: Is a temperature scale based on one proposed in 1724 by the European physicist Daniel Gabriel Fahrenheit (1686–1736). It uses the degree Fahrenheit (symbol: °F ) as the unit. Several accounts of how he originally defined his scale exist, but the original paper suggests the lower defining point, 0 °F, was established as the freezing temperature of a solution of brine made from a mixture of water, ice , and ammonium chloride (a salt ). The other limit established
1036-568: Is commonly still used alongside the Celsius scale in other countries that use the U.S. metrological service, such as Antigua and Barbuda , Saint Kitts and Nevis , the Bahamas , and Belize . A handful of British Overseas Territories , including the Virgin Islands , Montserrat , Anguilla , and Bermuda, also still use both scales. All other countries now use Celsius ("centigrade" until 1948), which
1110-402: Is in use in U.S. for all temperature measurements including weather forecasts, cooking, and food freezing temperatures, however for scientific research the scale is Celsius and Kelvin. Early in the 20th century, Halsey and Dale suggested that reasons for resistance to use the centigrade (now Celsius) system in the U.S. included the larger size of each degree Celsius and the lower zero point in
1184-449: Is named The Ole Rømer Observatory ( Ole Rømer Observatoriet [ da ] ) in his honour, and a Danish satellite project to measure the age, temperature, physical and chemical conditions of selected stars, was named The Rømer Satellite [ da ] . The satellite project stranded in 2002 and was never realised though. The Römer crater on the Moon is named after him. In
1258-449: Is rooted in the birth of the Danish national state during the 19th century. In this regard, Danish national identity was built on a basis of peasant culture and Lutheran theology , with Grundtvig and his popular movement playing a prominent part in the process. Two defining cultural criteria of being Danish were speaking the Danish language and identifying Denmark as a homeland. The ideology of Danishness has been politically important in
1332-556: Is still used on virtually all Canadian ovens. Thermometers, both digital and analog, sold in Canada usually employ both the Celsius and Fahrenheit scales. In the European Union, it is mandatory to use Kelvins or degrees Celsius when quoting temperature for "economic, public health, public safety and administrative" purposes, though degrees Fahrenheit may be used alongside degrees Celsius as
1406-498: Is the conventional symbol for the Fahrenheit temperature scale. A number followed by this symbol (and separated from it with a space) denotes a specific temperature point (e.g., " Gallium melts at 85.5763 °F"). A difference between temperatures or an uncertainty in temperature is also conventionally written the same way as well, e.g., "The output of the heat exchanger experiences an increase of 72 °F" or "Our standard uncertainty
1480-433: Is the value in degrees Fahrenheit, c the value in degrees Celsius, and k the value in kelvins: There is also an exact conversion between Celsius and Fahrenheit scales making use of the correspondence −40 °F ≘ −40 °C. Again, f is the numeric value in degrees Fahrenheit, and c the numeric value in degrees Celsius: When converting a temperature interval between the Fahrenheit and Celsius scales, only
1554-418: Is ±5 °F". However, some authors instead use the notation "An increase of 50 F°" (reversing the symbol order) to indicate temperature differences. Similar conventions exist for the Celsius scale, see Celsius § Temperatures and intervals . For an exact conversion between degrees Fahrenheit and Celsius, and kelvins of a specific temperature point , the following formulas can be applied. Here, f
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#17329024372271628-604: The Angles , Cimbri , Jutes , Herules , Teutones and others. The first mention of Danes within Denmark is on the Jelling Rune Stone , which mentions the conversion of the Danes to Christianity by Harald Bluetooth in the 10th century. Between c. 960 and the early 980s, Bluetooth established a kingdom in the lands of the Danes, stretching from Jutland to Scania. Around
1702-609: The Danish Golden Age during which a Danish national identity first came to be fully formed. The Danish liberal and national movements gained momentum in the 1830s, and after the European revolutions of 1848 Denmark became a constitutional monarchy on 5 June 1849. The growing bourgeoisie had demanded a share in government, and in an attempt to avert the sort of bloody revolution occurring elsewhere in Europe, Frederick VII gave in to
1776-453: The Danish language and the emotional relation to and identification with the nation of Denmark as the defining criteria of Danishness. This cultural definition of ethnicity has been suggested to be one of the reasons that Denmark was able to integrate their earliest ethnic minorities of Jewish and Polish origins into the Danish ethnic group with much more success than neighboring Germany. Jewishness
1850-687: The German lands in the early 16th century from the ideas of Martin Luther (1483–1546), had a considerable impact on Denmark. The Danish Reformation started in the mid-1520s. Some Danes wanted access to the Bible in their own language. In 1524, Hans Mikkelsen and Christiern Pedersen translated the New Testament into Danish ; it became an instant best-seller. Those who had traveled to Wittenberg in Saxony and come under
1924-568: The Kalmar Union . In 1523, Sweden won its independence, leading to the dismantling of the Kalmar Union and the establishment of Denmark–Norway . Denmark–Norway grew wealthy during the 16th century, largely because of the increased traffic through the Øresund . The Crown of Denmark could tax the traffic, because it controlled both sides of the Sound at the time. The Reformation , which originated in
1998-503: The meridian circle , the altazimuth , and the passage instrument (also known as the transit instrument , a type of meridian circle whose horizontal axis is not fixed in the east-west direction). The Ole Rømer Medal [ da ] is given annually by the Danish Natural Science Research Council for outstanding research. The Ole Rømer Museum is located in the municipality of Høje-Taastrup , Denmark, at
2072-717: The speed of light while working at the Royal Observatory in Paris and studying Jupiter 's moon Io . He estimated that light takes about 11 minutes to travel from the Sun to Earth. Using today's knowledge of the Sun-Earth distance , this would amount to a speed of light of approximately 220,000 kilometers per second, compared to today's accepted value of just under 300,000 kilometers per second. In scientific literature, alternative spellings such as "Roemer", "Römer", or "Romer" are common. Rømer
2146-404: The 1960s, the comic-book superhero The Flash on a number of occasions would measure his velocity in "Roemers" [ sic ], in honour of Ole Rømer's "discovery" of the speed of light . In Larry Niven 's 1999 novel Rainbow Mars , Ole Rømer is mentioned as having observed Martian life in an alternate history timeline. Ole Rømer features in the 2012 game Empire: Total War as
2220-399: The 1960s. In the late 1960s and 1970s, the Celsius scale replaced Fahrenheit in almost all of those countries—with the notable exception of the United States. Fahrenheit is used in the United States, its territories and associated states (all serviced by the U.S. National Weather Service ), as well as the (British) Cayman Islands and Liberia for everyday applications. The Fahrenheit scale
2294-621: The Danes during the post war period. At one point, a Canadian immigration office was to be set up in Copenhagen . In Greenland , a self-governing territory under Danish sovereignty , there are approximately 6,348 Danish Greenlanders making up roughly 11% of the territory's population. The most common Y-DNA haplogroups among Danes are R1b (37.3 %) and I1 (32.8 %). [REDACTED] Media related to Danes at Wikimedia Commons Fahrenheit scale The Fahrenheit scale ( / ˈ f æ r ə n h aɪ t , ˈ f ɑː r -/ )
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2368-405: The Fahrenheit scale is redefined slightly so that the freezing point of water was exactly 32 °F, and the boiling point was exactly 212 °F, or 180 degrees higher. It is for this reason that normal human body temperature is approximately 98.6 °F (oral temperature) on the revised scale (whereas it was 90° on Fahrenheit's multiplication of Rømer, and 96° on his original scale). In
2442-597: The Fahrenheit system; the Fahrenheit scale is supposedly more intuitive than Celsius for describing outdoor temperatures in temperate latitudes, with 100 °F being a hot summer day and 0 °F a cold winter day. Canada has passed legislation favoring the International System of Units , while also maintaining legal definitions for traditional Canadian imperial units. Canadian weather reports are conveyed using degrees Celsius with occasional reference to Fahrenheit especially for cross-border broadcasts . Fahrenheit
2516-577: The Spanish crown (1616–1617) but it proved to be impractical, because of the inaccuracies of Galileo's timetables and the difficulty of observing the eclipses on a ship. However, with refinements, the method could be made to work on land. After studies in Copenhagen, Rømer joined Jean Picard in 1671 to observe about 140 eclipses of Jupiter's moon Io on the island of Hven at the former location of Tycho Brahe ’s observatory of Uraniborg , near Copenhagen, over
2590-501: The United States are located in Solvang, California , and Racine, Wisconsin , but these populations are not considered to be Danes for official purposes by the Danish government , and heritage alone can not be used to claim Danish citizenship, as it can in some European nations. According to the 2006 Census, there were 200,035 Canadians with Danish background , 17,650 of whom were born in Denmark. Canada became an important destination for
2664-564: The United States, Brazil , Canada , Greenland and Argentina . Danish Americans ( Dansk-amerikanere ) are Americans of Danish descent. There are approximately 1,500,000 Americans of Danish origin or descent. Most Danish-Americans live in the Western United States or the Midwestern United States . California has the largest population of people of Danish descent in the United States. Notable Danish communities in
2738-485: The angle corresponding to a given Earth's position with respect to Jupiter, Δt = 22·( α ⁄ 180° )[minutes]. When the angle α is 180° the delay becomes 22 minutes, which may be interpreted as the time necessary for the light to cross a distance equal to the diameter of the Earth's orbit, H to E . (Actually, Jupiter is not visible from the conjunction point E .) That interpretation makes it possible to calculate
2812-533: The boiling point. On the Celsius scale, the freezing and boiling points of water were originally defined to be 100 degrees apart. A temperature interval of 1 °F was equal to an interval of 5 ⁄ 9 degrees Celsius. With the Fahrenheit and Celsius scales now both defined by the kelvin , this relationship was preserved, a temperature interval of 1 °F being equal to an interval of 5 ⁄ 9 K and of 5 ⁄ 9 °C. The Fahrenheit and Celsius scales intersect numerically at −40 in
2886-508: The centuries after this loss of territory, the populations of the Scanian lands , who had previously been considered Danish, came to be fully integrated as Swedes . In the early 19th century, Denmark suffered a defeat in the Napoleonic Wars ; Denmark lost control over Norway and territories in what is now northern Germany . The political and economic defeat ironically sparked what is known as
2960-412: The demands of the citizens. A new constitution emerged, separating the powers and granting the franchise to all adult males, as well as freedom of the press, religion, and association. The king became head of the executive branch . Danishness ( danskhed ) is the concept on which contemporary Danish national and ethnic identity is based. It is a set of values formed through the historic trajectory of
3034-401: The excavated site of Rømer's observatory Observatorium Tusculanum [ da ] at Vridsløsemagle. The observatory opened in 1704, and operated until about 1716, when the remaining instruments were moved to Rundetårn in Copenhagen. There is a large collection of ancient and more recent astronomical instruments on display at the museum. The museum opened in 1979, and has since 2002 been
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3108-489: The first national system for weights and measures in Denmark on 1 May 1683. Initially based on the Rhine foot, a more accurate national standard was adopted in 1698. Later measurements of the standards fabricated for length and volume show an excellent degree of accuracy. His goal was to achieve a definition based on astronomical constants, using a pendulum . This would happen after his death as practicalities made it too inaccurate at
3182-454: The formation of the Danish nation. The ideology of Danishness emphasizes the notion of historical connection between the population and the territory of Denmark and the relation between the thousand-year-old Danish monarchy and the modern Danish state, the 19th-century national romantic idea of "the people" ( folk ), a view of Danish society as homogeneous and socially egalitarian as well as strong cultural ties to other Scandinavian nations. As
3256-430: The former Danish Duchy of Schleswig . Excluded from this definition are people from the formerly Norway, Faroe Islands , and Greenland ; members of the German minority; and members of other ethnic minorities. Importantly, since its formulation, Danish identity has not been linked to a particular racial or biological heritage, as many other ethno-national identities have. N. F. S. Grundtvig , for example, emphasized
3330-463: The former Danish territory of Southern Schleswig ( Sydslesvig) , now located within the borders of Germany, forming around ten percent of the local population. In Denmark, the latter group is often referred to as "Danes south of the border" ( De danske syd for grænsen ), the "Danish-minded" ( de dansksindede ), or simply "South Schleswigers". Due to immigration there are considerable populations with Danish roots outside Denmark in countries such as
3404-503: The formulation of Danish political relations with the EU , which has been met with considerable resistance in the Danish population, and in recent reactions in the Danish public to the increasing influence of immigration . The Danish diaspora consists of emigrants and their descendants, especially those who maintain some of the customs of their Danish culture. A minority of approximately fifty thousand Danish-identifying German citizens live in
3478-653: The influence of the teachings of Luther and his associates included Hans Tausen , a Danish monk in the Order of St John Hospitallers . In the 17th century Denmark–Norway colonized Greenland . After a failed war with the Swedish Empire , the Treaty of Roskilde in 1658 removed the areas of the Scandinavian peninsula from Danish control, thus establishing the boundaries between Norway, Denmark, and Sweden that exist to this day. In
3552-466: The interval 6 times (since 64 = 2 ). Fahrenheit soon after observed that water boils at about 212 degrees using this scale. The use of the freezing and boiling points of water as thermometer fixed reference points became popular following the work of Anders Celsius , and these fixed points were adopted by a committee of the Royal Society led by Henry Cavendish in 1776–77. Under this system,
3626-422: The morale was alarmingly low. He was the inventor of the first street lights (oil lamps) in Copenhagen, and worked hard to try to control the beggars, poor people, unemployed, and prostitutes of Copenhagen. In Copenhagen, Rømer made rules for building new houses, got the city's water supply and sewers back in order, ensured that the city's fire department got new and better equipment, and was the moving force behind
3700-442: The need to be able to make this value reproducible using brine. According to a letter Fahrenheit wrote to his friend Herman Boerhaave , his scale was built on the work of Ole Rømer , whom he had met earlier. In Rømer scale , brine freezes at zero, water freezes and melts at 7.5 degrees, body temperature is 22.5, and water boils at 60 degrees. Fahrenheit multiplied each value by 4 in order to eliminate fractions and make
3774-672: The old Aarhus Katedralskole (the Cathedral school of Aarhus), moved to Copenhagen and matriculated at the University of Copenhagen . His mentor at the University was Rasmus Bartholin , who published his discovery of the double refraction of a light ray by Iceland spar (a transparent form of the mineral calcite ) in 1668, while Rømer was living in his home. Rømer was given every opportunity to learn mathematics and astronomy using Tycho Brahe 's astronomical observations, as Bartholin had been given
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#17329024372273848-525: The planning and making of new pavement in the streets and on the city squares. Rømer died at the age of 65 in 1710. He was buried in Copenhagen Cathedral , which has since been rebuilt following its destruction in the Battle of Copenhagen (1807) . There is a modern memorial. The determination of longitude is a significant practical problem in cartography and navigation . Philip III of Spain offered
3922-549: The present-day Fahrenheit scale, 0 °F no longer corresponds to the eutectic temperature of ammonium chloride brine as described above. Instead, that eutectic is at approximately 4 °F on the final Fahrenheit scale. The Rankine temperature scale was based upon the Fahrenheit temperature scale, with its zero representing absolute zero instead. The Fahrenheit scale was the primary temperature standard for climatic, industrial and medical purposes in Anglophone countries until
3996-482: The ratio is used, without any constant (in this case, the interval has the same numeric value in kelvins as in degrees Celsius): Fahrenheit proposed his temperature scale in 1724, basing it on two reference points of temperature. In his initial scale (which is not the final Fahrenheit scale), the zero point was determined by placing the thermometer in "a mixture of ice , water, and salis Armoniaci [transl. ammonium chloride ] or even sea salt". This combination forms
4070-442: The rationale to keep using Fahrenheit was one of emphasis for high temperatures: "−6 °C" sounds colder than "21 °F", and "94 °F" sounds more sensational than "34 °C". Unicode provides the Fahrenheit symbol at code point U+2109 ℉ DEGREE FAHRENHEIT . However, this is a compatibility character encoded for roundtrip compatibility with legacy encodings. The Unicode standard explicitly discourages
4144-518: The respective unit (i.e., −40 °F ≘ −40 °C). Absolute zero is 0 K, −273.15 °C, or −459.67 °F. The Rankine temperature scale uses degree intervals of the same size as those of the Fahrenheit scale, except that absolute zero is 0 °R – the same way that the Kelvin temperature scale matches the Celsius scale, except that absolute zero is 0 K. The combination of degree symbol (°) followed by an uppercase letter F
4218-661: The same time, he received a visit from a German missionary who, by surviving an ordeal by fire according to legend, convinced Harold to convert to Christianity . The following years saw the Danish Viking expansion , which incorporated Norway and England into the Danish North Sea Empire . After the death of Canute the Great in 1035, England broke away from Danish control. Canute's nephew Sweyn Estridson (1020–74) re-established strong royal Danish authority and built
4292-489: The satellite; light seems to take about ten to eleven minutes [to cross] a distance equal to the half-diameter of the terrestrial orbit . Oddly, Cassini seems to have abandoned this reasoning, which Rømer adopted and set about buttressing in an irrefutable manner, using a selected number of observations performed by Picard and himself between 1671 and 1677. Rømer presented his results to the French Academy of Sciences , and it
4366-456: The satellites of Jupiter as Cassini's assistant. Rømer added his own observations to Cassini's and observed that times between eclipses (particularly those of Io) got shorter as Earth approached Jupiter, and longer as Earth moved farther away. Cassini made an announcement to the Academy of Sciences on 22 August 1676: This second inequality appears to be due to light taking some time to reach us from
4440-404: The scale more fine-grained . He then re-calibrated his scale using the melting point of ice and normal human body temperature (which were at 30 and 90 degrees); he adjusted the scale so that the melting point of ice would be 32 degrees, and body temperature 96 degrees, so that 64 intervals would separate the two, allowing him to mark degree lines on his instruments by simply bisecting
4514-426: The so-called aberration of light were made by James Bradley in 1727. In 1809, again making use of observations of Io, but this time with the benefit of more than a century of increasingly precise observations, the astronomer Jean Baptiste Joseph Delambre reported the time for light to travel from the Sun to the Earth as 8 minutes and 12 seconds. Depending on the value assumed for the astronomical unit, this yields
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#17329024372274588-493: The speed of light as just a little more than 300,000 kilometres per second. The modern value is 8 minutes and 19 seconds, and a speed of 299,792.458 km/s. A plaque at the Observatory of Paris, where the Danish astronomer happened to be working, commemorates what was, in effect, the first measurement of a universal quantity made on this planet. In addition to inventing the first street lights in Copenhagen, Rømer also invented
4662-414: The strict result of Rømer's observations: The ratio of the speed of light to the speed with which Earth orbits the sun, which is the ratio of the duration of a year divided by pi as compared to the 22 minutes 365·24·60 ⁄ π ·22 ≈ 7,600. In comparison, the modern value is circa 299,792 km s ⁄ 29.8 km s ≈ 10,100. Rømer neither calculated this ratio, nor did he give
4736-402: The table below, his observations in 1676, including the one on 7 August, believed to be at the opposition point H , and the one observed at Paris Observatory to be 10 minutes late, on 9 November. By trial and error , during eight years of observations Rømer worked out how to account for the retardation of light when reckoning the ephemeris of Io. He calculated the delay as a proportion of
4810-527: The task of preparing them for publication. Rømer was employed by the French government: Louis XIV made him tutor for the Dauphin , and he also took part in the construction of the magnificent fountains at Versailles . In 1681, Rømer returned to Denmark and was appointed professor of astronomy at the University of Copenhagen, and the same year he married Anne Marie Bartholin, the daughter of Rasmus Bartholin . He
4884-514: The time. Notable is also his definition of the new Danish mile of 24,000 Danish feet (circa 7,532 m). In 1700, Rømer persuaded the king to introduce the Gregorian calendar in Denmark and Norway – something Tycho Brahe had argued for in vain a hundred years earlier. Rømer developed a temperature scale while convalescing from a broken leg. After visiting with Rømer in 1708, Daniel Gabriel Fahrenheit began making his thermometers using
4958-529: Was active also as an observer, both at the University Observatory at Rundetårn and in his home, using improved instruments of his own construction. Unfortunately, his observations have not survived: they were lost in the great Copenhagen Fire of 1728 . However, a former assistant (and later an astronomer in his own right), Peder Horrebow , loyally described and wrote about Rømer's observations. In Rømer's position as royal mathematician, he introduced
5032-581: Was as follows. Referring to the illustration, assume the Earth is at point L , and Io emerges from Jupiter's shadow at point D . After several orbits of Io, at 42.5 hours per orbit, the Earth is at point K . If light is not propagated instantaneously, the additional time it takes to reach K , which he reckoned about 3½ minutes, would explain the observed delay. Rømer observed immersions at point C from positions F and G , to avoid confusion with eclipses (Io shadowed by Jupiter from C to D ) and occultations (Io hidden behind Jupiter at various angles). In
5106-461: Was born on 25 September 1644 in Århus to merchant and skipper Christen Pedersen (died 1663), and Anna Olufsdatter Storm ( c. 1610 – 1690), daughter of a well-to-do alderman . Since 1642, Christen Pedersen had taken to using the name Rømer, which means that he was from the Danish island of Rømø , to distinguish himself from a couple of other people named Christen Pedersen. There are few records of Ole Rømer before 1662, when he graduated from
5180-651: Was defined to be 212 °F, both at sea level and under standard atmospheric pressure . It is now formally defined using the Kelvin scale. It continues to be used in the United States (including its unincorporated territories ), its freely associated states in the Western Pacific ( Palau , the Federated States of Micronesia and the Marshall Islands ), the Cayman Islands , and Liberia . Fahrenheit
5254-415: Was his best estimate of the average human body temperature , originally set at 90 °F, then 96 °F (about 2.6 °F less than the modern value due to a later redefinition of the scale). For much of the 20th century, the Fahrenheit scale was defined by two fixed points with a 180 °F separation: the temperature at which pure water freezes was defined as 32 °F and the boiling point of water
5328-402: Was invented 18 years after the Fahrenheit scale. Historically, on the Fahrenheit scale the freezing point of water was 32 °F, and the boiling point was 212 °F (at standard atmospheric pressure ). This put the boiling and freezing points of water 180 degrees apart. Therefore, a degree on the Fahrenheit scale was 1 ⁄ 180 of the interval between the freezing point and
5402-509: Was not seen as being incompatible with a Danish ethnic identity, as long as the most important cultural practices and values were shared. This inclusive ethnicity has in turn been described as the background for the relative lack of virulent antisemitism in Denmark and the rescue of the Danish Jews , saving 99% of Denmark's Jewish population from the Holocaust . Modern Danish cultural identity
5476-501: Was summarised soon after by an anonymous reporter in a short paper, Démonstration touchant le mouvement de la lumière trouvé par M. Roemer de l'Académie des sciences , published 7 December 1676 in the Journal des sçavans . Unfortunately, the reporter, possibly in order to hide his lack of understanding, resorted to cryptic phrasing, obfuscating Rømer's reasoning in the process. Rømer himself never published his results. Rømer's reasoning
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