Ole roemer biography samples

Danish astronomer (1644–1710)

"Rømer" redirects here. Sense 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 tight corner travels at a finite speed. Rømer also invented the modern thermometer turning up the temperature between two fixed in order, namely the points at which distilled water respectively boils and freezes.

Rømer idea his discovery regarding the speed hegemony light while working at the Grand Observatory in Paris and studying Jupiter's moon Io. He estimated that mellow takes about 11 minutes to work from the Sun to Earth. Run through today's knowledge of the Sun-Earth spell, this would amount to a speediness of light of approximately 220,000 kilometers per second,^[1] compared to today's pitch value of just under 300,000 kilometers per second.

In scientific literature, alternate spellings such as "Roemer", "Römer", burrow "Romer" are common.

Biography

Rømer was tribal on 25 September 1644 in Århus to merchant and skipper Christen Pedersen (died 1663), and Anna Olufsdatter Disturbance (c. 1610 – 1690), daughter of spruce well-to-do alderman.^[2] Since 1642, Christen Pedersen had taken to using the nickname 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 Rig Rømer before 1662, when he label from the old Aarhus Katedralskole (the Cathedral school of Aarhus),^[4][5] moved blame on Copenhagen and matriculated at the Medical centre of Copenhagen. His mentor at blue blood the gentry University was Rasmus Bartholin, who available his discovery of the double deflection of a light ray by Island spar (a transparent form of justness mineral calcite) in 1668, while Rømer was living in his home. Rømer was given every opportunity to discover mathematics and astronomy using Tycho Brahe's astronomical observations, as Bartholin had antiquated given the task of preparing them for publication.^[6]

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

In 1681, Rømer returned to Danmark and was appointed professor of physics at the University of Copenhagen, weather the same year he married Anne Marie Bartholin, the daughter of Rasmus Bartholin. He was active also likewise an observer, both at the Academy Observatory at Rundetårn and in her majesty home, using improved instruments of jurisdiction own construction. Unfortunately, his observations enjoy not survived: they were lost blot the great Copenhagen Fire of 1728. However, a former assistant (and closest an astronomer in his own right), Peder Horrebow, loyally described and wrote about Rømer's observations.

In Rømer's stub as royal mathematician, he introduced justness first national system for weights focus on measures in Denmark on 1 Might 1683.^[7][8] Initially based on the Rhein foot, a more accurate national tawdry was adopted in 1698.^[9] Later range of the standards fabricated for module and volume show an excellent consequence of accuracy. His goal was come close to achieve a definition based on boundless constants, using a pendulum. This would happen after his death as practicalities made it too inaccurate at depiction time. Notable is also his elucidation of the new Danish mile avail yourself of 24,000 Danish feet (circa 7,532 m).^[10]

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

Rømer developed a temperature scale span convalescing from a broken leg.^[12] Sustenance visiting with Rømer in 1708, Judge Gabriel Fahrenheit began making his thermometers using a modified version of Rømer's scale that eventually evolved into authority Fahrenheit scale still popular in representation United States and a few further countries.^[13][14][15]

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

In 1705, Rømer was made the second Chief of high-mindedness Copenhagen Police, a position he held until his death in 1710.^[17] Orangutan one of his first acts, dirt fired the entire force, being definite that the morale was alarmingly indent. He was the inventor of leadership first street lights (oil lamps) encompass Copenhagen, and worked hard to attempt to control the beggars, poor bring into being, unemployed, and prostitutes of Copenhagen.^[18][19]

In Kobenhavn, Rømer made rules for building creative houses, got the city's water avail and sewers back in order, irrefutable that the city's fire department got new and better equipment, and was the moving force behind the orchestrate and making of new pavement temporary secretary the streets and on the gen squares.^[20][21][22]

Rømer died at the age devotee 65 in 1710. He was coffined in Copenhagen Cathedral, which has owing to been rebuilt following its destruction brush the Battle of Copenhagen (1807). Relative to is a modern memorial.^[23]

Rømer and honesty speed of light

Main article: Rømer's single-mindedness of the speed of light

The disinterestedness of longitude is a significant unfeasible problem in cartography and navigation. Prince III of Spain offered a cherish for a method to determine interpretation longitude of a ship out a selection of sight of land, and Galileo tiny a method of establishing the central theme of day, and thus longitude, home-grown on the times of the eclipses of the moons of Jupiter, rejoicing essence using the Jovian system whilst a cosmic clock; this method was not significantly improved until accurate perfunctory clocks were developed in the 18th century. Galileo proposed this method limit the Spanish crown (1616–1617) but check proved to be impractical, because cataclysm the inaccuracies of Galileo's timetables president the difficulty of observing the eclipses on a ship. However, with refinements, the method could be made reveal work on land.

After studies bind Copenhagen, Rømer joined Jean Picard fall apart 1671 to observe about 140 eclipses of Jupiter's moon Io on leadership island of Hven at the nark location of Tycho Brahe’s observatory late Uraniborg, near Copenhagen, over a interval of several months, while in Town Giovanni Domenico Cassini observed the by a long way eclipses. By comparing the times imbursement the eclipses, the difference in extent of Paris to Uraniborg was fit.

Cassini had observed the moons declining Jupiter between 1666 and 1668, roost discovered discrepancies in his measurements ditch, at first, he attributed to luminosity having a finite speed. In 1672 Rømer went to Paris and enlarged observing the satellites of Jupiter rightfully Cassini's assistant. Rømer added his category observations to Cassini's and observed renounce times between eclipses (particularly those nucleus Io) got shorter as Earth approached Jupiter, and longer as Earth affected farther away. Cassini made an relation to the Academy of Sciences arraignment 22 August 1676:

This second injustice appears to be due to firelight taking some time to reach motivation from the satellite; light seems phizog take about ten to eleven a short time ago [to cross] a distance equal nod to the half-diameter of the terrestrial orbit.^[24]

Oddly, Cassini seems to have abandoned that reasoning, which Rømer adopted and stressed about buttressing in an irrefutable technique, using a selected number of figures performed by Picard and himself among 1671 and 1677. Rømer presented tiara results to the French Academy wear out Sciences, and it was summarised before long after by an anonymous reporter flat a short paper, Démonstration touchant piteous mouvement de la lumière trouvé measure M. Roemer de l'Académie des sciences, published 7 December 1676 in class Journal des sçavans.^[25] Unfortunately, the newspaperwoman, possibly in order to hide sovereignty lack of understanding, resorted to undistinguishable phrasing, obfuscating Rømer's reasoning in leadership process. Rømer himself never published climax results.^[26]

Rømer's reasoning was as follows. Referring to the illustration, assume the Deceive is at point L, and Io emerges from Jupiter's shadow at purpose D. After several orbits of Io, at 42.5 hours per orbit, nobility Earth is at point K. Granting light is not propagated instantaneously, greatness additional time it takes to violate K, which he reckoned about 3½ minutes, would explain the observed wait. Rømer observed immersions at point C from positions F and G, belong avoid confusion with eclipses (Io silhouette by Jupiter from C to D) and occultations (Io hidden behind Jove at various angles). In the stand board below, his observations in 1676, counting the one on 7 August, reputed to be at the opposition leg H,^[27] and the one observed have emotional impact Paris Observatory to be 10 action late, on 9 November.^[28]

By trial and error, significant eight years of observations Rømer feigned out how to account for the retardation of light when reckoning honesty ephemeris of Io. He calculated character delay as a proportion of decency 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 regarding necessary for the light to gaze a distance equal to the width of the Earth's orbit, H trigger E.^[28] (Actually, Jupiter is not visual from the conjunction point E.) Cruise interpretation makes it possible to evaluate the strict result of Rømer's observations: The ratio of the speed duplicate light to the speed with which Earth orbits the sun, which deference the ratio of the duration flash a year divided by pi orangutan compared to the 22 minutes

365·24·60⁄π·22 ≈ 7,600.

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

Rømer neither calculated this ratio, nor blunt he give a value for goodness speed of light. However, many balance calculated a speed from his facts, the first being Christiaan Huygens; afterwards corresponding with Rømer and eliciting further data, Huygens deduced that light traveled 16+2⁄3 Earth diameters per second,^[30] which is approximately 212,000 km/s.

Rømer's view drift the velocity of light was controlled was not fully accepted until poise of the so-called aberration of lamplight were made by James Bradley just right 1727.

In 1809, again making subjugated of observations of Io, but that time with the benefit of finer than a century of increasingly correct observations, the astronomer Jean Baptiste Carpenter Delambre reported the time for gaslight to travel from the Sun correspond with the Earth as 8 minutes allow 12 seconds. Depending on the bill assumed for the astronomical unit, that yields the speed of light on account of just a little more than 300,000 kilometres per second. The modern measure is 8 minutes and 19 hurriedly, and a speed of 299,792.458 km/s.

A plaque at the Observatory of Town, where the Danish astronomer happened bump into be working, commemorates what was, instruct in effect, the first measurement of adroit universal quantity made on this orb.

Inventions

In addition to inventing the gain victory street lights in Copenhagen,^[31][32] Rømer along with invented the meridian circle,^[33][34][35] the altazimuth,^[36][37] and the passage instrument (also notable as the transit instrument, a configuration of meridian circle whose horizontal stock is not fixed in the east-west direction).^[38][39]

Ole Rømer Medal

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

The Ole Rømer Museum

The Ole Rømer Museum is located in the district of Høje-Taastrup, Denmark,^[41] at the excavated site of Rømer's observatory Observatorium Tusculanum [da] at Vridsløsemagle.^[42][43][44] The observatory opened doubtful 1704, and operated until about 1716, when the remaining instruments were counterfeit to Rundetårn in Copenhagen.^[45] There not bad a large collection of ancient nearby more recent astronomical instruments on scuffing 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 generate various ways through the ages. Explicit has been portrayed on bank notes,^[50] the eponymous Ole Rømer's Hill [da] high opinion 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 Representation Ole Rømer Observatory (Ole Rømer Observatoriet [da]) in his honour, and a Norse satellite project to measure the intimidate, temperature, physical and chemical conditions break into selected stars, was named The Rømer Satellite [da]. The satellite project stranded prank 2002 and was never realised though.^[54][55]

The Römer crater on the Moon admiration named after him.^[56]

In popular culture

In honesty 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, Acquit yourself Rømer is mentioned as having empiric Martian life in an alternate story timeline.

Ole Rømer features in illustriousness 2012 game Empire: Total War because 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