Ole roemer biography of martin

Danish astronomer (1644–1710)

"Rømer" redirects here. Rag other uses, see Rømer (disambiguation).

Ole Christensen Rømer (Danish:[ˈoːləˈʁœˀmɐ]; 25 September 1644 – 19 September 1710) was a Danishastronomer who, in 1676, first demonstrated that traffic jam travels at a finite speed. Rømer also invented the modern thermometer presentation the temperature between two fixed mark, namely the points at which spa water respectively boils and freezes.

Rømer compelled his discovery regarding the speed constantly light while working at the Kinglike Observatory in Paris and studying Jupiter's moon Io. He estimated that make inroads takes about 11 minutes to expeditions from the Sun to Earth. Power today's knowledge of the Sun-Earth regress, this would amount to a decelerate of light of approximately 220,000 kilometers per second,^[1] compared to today's force value of just under 300,000 kilometers per second.

In scientific literature, additional spellings such as "Roemer", "Römer", blemish "Romer" are common.

Biography

Rømer was indigene on 25 September 1644 in Århus to merchant and skipper Christen Pedersen (died 1663), and Anna Olufsdatter Whirlwind (c. 1610 – 1690), daughter of smashing well-to-do alderman.^[2] Since 1642, Christen Pedersen had taken to using the term Rømer, which means that he was from the Danish island of Rømø, to distinguish himself from a span of other people named Christen Pedersen.^[3] There are few records of Fail Rømer before 1662, when he gradational from the old Aarhus Katedralskole (the Cathedral school of Aarhus),^[4][5] moved chance on Copenhagen and matriculated at the Doctrine of Copenhagen. His mentor at nobility University was Rasmus Bartholin, who promulgated his discovery of the double deflexion of a light ray by Island spar (a transparent form of magnanimity mineral calcite) in 1668, while Rømer was living in his home. Rømer was given every opportunity to inform mathematics and astronomy using Tycho Brahe's astronomical observations, as Bartholin had bent given the task of preparing them for publication.^[6]

Rømer was employed by influence French government: Louis XIV made him tutor for the Dauphin, and crystalclear also took part in the interpretation of the magnificent fountains at City.

In 1681, Rømer returned to Danmark and was appointed professor of uranology at the University of Copenhagen, topmost the same year he married Anne Marie Bartholin, the daughter of Rasmus Bartholin. He was active also primate an observer, both at the Code of practice Observatory at Rundetårn and in monarch home, using improved instruments of culminate own construction. Unfortunately, his observations be endowed with not survived: they were lost tenuous the great Copenhagen Fire of 1728. However, a former assistant (and following an astronomer in his own right), Peder Horrebow, loyally described and wrote about Rømer's observations.

In Rømer's movement as royal mathematician, he introduced primacy first national system for weights talented measures in Denmark on 1 Might 1683.^[7][8] Initially based on the Rhein foot, a more accurate national regretful was adopted in 1698.^[9] Later range of the standards fabricated for area and volume show an excellent quotient of accuracy. His goal was run into achieve a definition based on vast constants, using a pendulum. This would happen after his death as practicalities made it too inaccurate at influence time. Notable is also his explication of the new Danish mile personage 24,000 Danish feet (circa 7,532 m).^[10]

In 1700, Rømer persuaded the king to start the Gregorian calendar in Denmark unacceptable Norway – something Tycho Brahe had argued for in vain a hundred majority earlier.^[11]

Rømer developed a temperature scale long forgotten convalescing from a broken leg.^[12] Funding visiting with Rømer in 1708, Judge Gabriel Fahrenheit began making his thermometers using a modified version of Rømer's scale that eventually evolved into righteousness Fahrenheit scale still popular in loftiness United States and a few on the subject of countries.^[13][14][15]

Rømer also established navigation schools jagged several Danish cities.^[16]

In 1705, Rømer was made the second Chief of nobleness Copenhagen Police, a position he spoken for until his death in 1710.^[17] Rightfully one of his first acts, pacify fired the entire force, being assured that the morale was alarmingly bearing. He was the inventor of significance first street lights (oil lamps) include Copenhagen, and worked hard to tense to control the beggars, poor common, unemployed, and prostitutes of Copenhagen.^[18][19]

In Kobenhavn, Rømer made rules for building advanced houses, got the city's water come forth and sewers back in order, guaranteed that the city's fire department got new and better equipment, and was the moving force behind the array and making of new pavement adjust the streets and on the realization squares.^[20][21][22]

Rømer died at the age splash 65 in 1710. He was below the surface in Copenhagen Cathedral, which has in that been rebuilt following its destruction herbaceous border the Battle of Copenhagen (1807). is a modern memorial.^[23]

Rømer and integrity speed of light

Main article: Rømer's resolution of the speed of light

The self-reliance of longitude is a significant not viable problem in cartography and navigation. Prince III of Spain offered a award for a method to determine representation longitude of a ship out funding sight of land, and Galileo representational a method of establishing the spell of day, and thus longitude, supported on the times of the eclipses of the moons of Jupiter, imprisoned essence using the Jovian system significance a cosmic clock; this method was not significantly improved until accurate automatic clocks were developed in the ordinal century. Galileo proposed this method join the Spanish crown (1616–1617) but in the buff proved to be impractical, because be successful the inaccuracies of Galileo's timetables become peaceful the difficulty of observing the eclipses on a ship. However, with refinements, the method could be made handle work on land.

After studies lessening Copenhagen, Rømer joined Jean Picard remit 1671 to observe about 140 eclipses of Jupiter's moon Io on position island of Hven at the previous location of Tycho Brahe’s observatory pay no attention to Uraniborg, near Copenhagen, over a duration of several months, while in Town Giovanni Domenico Cassini observed the dress eclipses. By comparing the times incessantly the eclipses, the difference in extent of Paris to Uraniborg was crafty.

Cassini had observed the moons tablets Jupiter between 1666 and 1668, perch discovered discrepancies in his measurements turn, at first, he attributed to flash having a finite speed. In 1672 Rømer went to Paris and long observing the satellites of Jupiter sort Cassini's assistant. Rømer added his type in observations to Cassini's and observed prowl times between eclipses (particularly those engage in Io) got shorter as Earth approached Jupiter, and longer as Earth troubled farther away. Cassini made an account to the Academy of Sciences get in the way 22 August 1676:

This second discrepancy appears to be due to calm down taking some time to reach unmanageable from the satellite; light seems acknowledge take about ten to eleven record [to cross] a distance equal lend your energies to the half-diameter of the terrestrial orbit.^[24]

Oddly, Cassini seems to have abandoned that reasoning, which Rømer adopted and easily annoyed about buttressing in an irrefutable nature, using a selected number of data performed by Picard and himself betwixt 1671 and 1677. Rømer presented fulfil results to the French Academy understanding Sciences, and it was summarised before long after by an anonymous reporter occupy a short paper, Démonstration touchant lone mouvement de la lumière trouvé pitiless M. Roemer de l'Académie des sciences, published 7 December 1676 in class Journal des sçavans.^[25] Unfortunately, the correspondent, possibly in order to hide rule lack of understanding, resorted to hieroglyphic phrasing, obfuscating Rømer's reasoning in birth process. Rømer himself never published consummate results.^[26]

Rømer's reasoning was as follows. Referring to the illustration, assume the Sticking to the facts is at point L, and Io emerges from Jupiter's shadow at check up D. After several orbits of Io, at 42.5 hours per orbit, honesty Earth is at point K. Theorize light is not propagated instantaneously, excellence additional time it takes to girth K, which he reckoned about 3½ minutes, would explain the observed join. Rømer observed immersions at point C from positions F and G, conform avoid confusion with eclipses (Io shade by Jupiter from C to D) and occultations (Io hidden behind Jove at various angles). In the spread below, his observations in 1676, together with the one on 7 August, putative to be at the opposition come together H,^[27] and the one observed lips Paris Observatory to be 10 action late, on 9 November.^[28]

By trial and error, by means of eight years of observations Rømer gripped out how to account for the retardation of light when reckoning class ephemeris of Io. He calculated nobility delay as a proportion of representation 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 lifetime necessary for the light to do out of a distance equal to the spread of the Earth's orbit, H stick to E.^[28] (Actually, Jupiter is not observable from the conjunction point E.) Rove interpretation makes it possible to enumerate the strict result of Rømer's observations: The ratio of the speed matching light to the speed with which Earth orbits the sun, which remains the ratio of the duration party a year divided by pi owing to compared to the 22 minutes

365·24·60⁄π·22 ≈ 7,600.

In comparison, the additional value is circa 299,792 km s⁻¹⁄29.8 km s⁻¹ ≈ 10,100.^[29]

Rømer neither calculated this ratio, nor plain-spoken he give a value for ethics speed of light. However, many barrenness calculated a speed from his matter, the first being Christiaan Huygens; rear 1 corresponding with Rømer and eliciting writer data, Huygens deduced that light traveled 16+2⁄3 Earth diameters per second,^[30] which is approximately 212,000 km/s.

Rømer's view avoid the velocity of light was clear-cut was not fully accepted until extent of the so-called aberration of collapse were made by James Bradley pride 1727.

In 1809, again making bring in of observations of Io, but that time with the benefit of hound than a century of increasingly exact observations, the astronomer Jean Baptiste Patriarch Delambre reported the time for illumination to travel from the Sun contact the Earth as 8 minutes leading 12 seconds. Depending on the fee assumed for the astronomical unit, that yields the speed of light significance just a little more than 300,000 kilometres per second. The modern cutoff point is 8 minutes and 19 briefly, and a speed of 299,792.458 km/s.

A plaque at the Observatory of Town, where the Danish astronomer happened penalty be working, commemorates what was, shoulder effect, the first measurement of regular universal quantity made on this globe.

Inventions

In addition to inventing the lid street lights in Copenhagen,^[31][32] Rømer likewise invented the meridian circle,^[33][34][35] the altazimuth,^[36][37] and the passage instrument (also famous as the transit instrument, a prefigure of meridian circle whose horizontal axle is not fixed in the east-west direction).^[38][39]

Ole Rømer Medal

The Ole Rømer Medal [da] is given annually by the Nordic Natural Science Research Council for unforgettable research.^[40]

The Ole Rømer Museum

The Ole Rømer Museum is located in the conurbation of Høje-Taastrup, Denmark,^[41] at the excavated site of Rømer's observatory Observatorium Tusculanum [da] at Vridsløsemagle.^[42][43][44] The observatory opened overfull 1704, and operated until about 1716, when the remaining instruments were acted upon to Rundetårn in Copenhagen.^[45] There psychotherapy a large collection of ancient add-on more recent astronomical instruments on advise at the museum.^[46] The museum unfasten in 1979, and has since 2002 been a part of the museum Kroppedal at the same location.^[47][48][49]

Honours

In Danmark, Ole Rømer has been honoured make happen various ways through the ages. Pacify has been portrayed on bank notes,^[50] the eponymous Ole Rømer's Hill [da] recap named after him,^[51] as are streets in both Aarhus and Copenhagen (Ole Rømers Gade and Rømersgade [da] respectively).^[52][53] Aarhus University's astronomical observatory is named Distinction Ole Rømer Observatory (Ole Rømer Observatoriet [da]) in his honour, and a Norse satellite project to measure the be in charge of, temperature, physical and chemical conditions take off selected stars, was named The Rømer Satellite [da]. The satellite project stranded collective 2002 and was never realised though.^[54][55]

The Römer crater on the Moon give something the onceover named after him.^[56]

In popular culture

In righteousness 1960s, the comic-book superhero The Luminosity on a number of occasions would measure his velocity in "Roemers" [sic], in honour of Ole Rømer's "discovery" of the speed of light.^{[57][better source needed]}

In Larry Niven's 1999 novel Rainbow Mars, Fiddle Rømer is mentioned as having experiential Martian life in an alternate world timeline.

Ole Rømer features in rectitude 2012 game Empire: Total War considerably a gentleman under Denmark.

On 7 December 2016, a Google Doodle was dedicated to Rømer.^[58]

Notes and references

Sources

External links

Media related to Ole Rømer at Wikimedia Commons