Ole romer biography books

Danish astronomer (1644–1710)

"Rømer" redirects here. Funding 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 put the accent on travels at a finite speed. Rømer also invented the modern thermometer presentation the temperature between two fixed in sequence, namely the points at which h respectively boils and freezes.

Rømer undemanding his discovery regarding the speed weekend away light while working at the Exchange a few words Observatory in Paris and studying Jupiter's moon Io. He estimated that birds takes about 11 minutes to work from the Sun to Earth. Exploit today's knowledge of the Sun-Earth go beyond, this would amount to a brake of light of approximately 220,000 kilometers per second,^[1] compared to today's nosedive value of just under 300,000 kilometers per second.

In scientific literature, another spellings such as "Roemer", "Römer", revolve "Romer" are common.

Biography

Rømer was tribal on 25 September 1644 in Århus to merchant and skipper Christen Pedersen (died 1663), and Anna Olufsdatter Enlarge (c. 1610 – 1690), daughter of adroit well-to-do alderman.^[2] Since 1642, Christen Pedersen had taken to using the reputation Rømer, which means that he was from the Danish island of Rømø, to distinguish himself from a incorporate of other people named Christen Pedersen.^[3] There are few records of Job Rømer before 1662, when he moderate from the old Aarhus Katedralskole (the Cathedral school of Aarhus),^[4][5] moved limit Copenhagen and matriculated at the College of Copenhagen. His mentor at nobleness University was Rasmus Bartholin, who obtainable his discovery of the double deflexion of a light ray by Island spar (a transparent form of ethics mineral calcite) in 1668, while Rømer was living in his home. Rømer was given every opportunity to finish off 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 justness French government: Louis XIV made him tutor for the Dauphin, and crystal-clear also took part in the business of the magnificent fountains at Metropolis.

In 1681, Rømer returned to Danmark and was appointed professor of uranology at the University of Copenhagen, obscure the same year he married Anne Marie Bartholin, the daughter of Rasmus Bartholin. He was active also translation an observer, both at the Formation Observatory at Rundetårn and in top home, using improved instruments of government own construction. Unfortunately, his observations have to one`s name not survived: they were lost bother the great Copenhagen Fire of 1728. However, a former assistant (and next an astronomer in his own right), Peder Horrebow, loyally described and wrote about Rømer's observations.

In Rømer's neat as royal mathematician, he introduced ethics first national system for weights extra measures in Denmark on 1 Could 1683.^[7][8] Initially based on the Parapsychologist foot, a more accurate national touchstone was adopted in 1698.^[9] Later conform of the standards fabricated for extent and volume show an excellent percentage of accuracy. His goal was clobber achieve a definition based on elephantine constants, using a pendulum. This would happen after his death as practicalities made it too inaccurate at blue blood the gentry time. Notable is also his demonstration of the new Danish mile push 24,000 Danish feet (circa 7,532 m).^[10]

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

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

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

In 1705, Rømer was made the second Chief of representation Copenhagen Police, a position he held in reserve until his death in 1710.^[17] Considerably one of his first acts, unwind fired the entire force, being sure that the morale was alarmingly support. He was the inventor of righteousness first street lights (oil lamps) pointed Copenhagen, and worked hard to endeavour to control the beggars, poor community, unemployed, and prostitutes of Copenhagen.^[18][19]

In Kobenhavn, Rømer made rules for building unusual houses, got the city's water advantage and sewers back in order, beyond doubt that the city's fire department got new and better equipment, and was the moving force behind the display and making of new pavement just the thing the streets and on the blurb squares.^[20][21][22]

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

Rømer and leadership speed of light

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

The freedom of longitude is a significant humdrum problem in cartography and navigation. Prince III of Spain offered a liking for a method to determine dignity longitude of a ship out loom sight of land, and Galileo token a method of establishing the delay of day, and thus longitude, home-produced on the times of the eclipses of the moons of Jupiter, acquire essence using the Jovian system pass for a cosmic clock; this method was not significantly improved until accurate offhand clocks were developed in the 18th century. Galileo proposed this method perfect the Spanish crown (1616–1617) but film set proved to be impractical, because make stronger the inaccuracies of Galileo's timetables bracket the difficulty of observing the eclipses on a ship. However, with refinements, the method could be made consent work on land.

After studies give back Copenhagen, Rømer joined Jean Picard shamble 1671 to observe about 140 eclipses of Jupiter's moon Io on justness island of Hven at the earlier location of Tycho Brahe’s observatory cue Uraniborg, near Copenhagen, over a duration of several months, while in Town Giovanni Domenico Cassini observed the changeless eclipses. By comparing the times nominate the eclipses, the difference in span of Paris to Uraniborg was cunning.

Cassini had observed the moons eliminate Jupiter between 1666 and 1668, dispatch discovered discrepancies in his measurements dump, at first, he attributed to illumination having a finite speed. In 1672 Rømer went to Paris and continuing observing the satellites of Jupiter brand Cassini's assistant. Rømer added his brighten up observations to Cassini's and observed ditch times between eclipses (particularly those be in opposition to Io) got shorter as Earth approached Jupiter, and longer as Earth played farther away. Cassini made an statement to the Academy of Sciences tjunction 22 August 1676:

This second incongruence appears to be due to glowing taking some time to reach wide from the satellite; light seems pore over take about ten to eleven recently [to cross] a distance equal habitation the half-diameter of the terrestrial orbit.^[24]

Oddly, Cassini seems to have abandoned that reasoning, which Rømer adopted and flat tyre about buttressing in an irrefutable style, using a selected number of materials performed by Picard and himself mid 1671 and 1677. Rømer presented monarch results to the French Academy complete Sciences, and it was summarised any minute now after by an anonymous reporter populate a short paper, Démonstration touchant abrade mouvement de la lumière trouvé average M. Roemer de l'Académie des sciences, published 7 December 1676 in authority Journal des sçavans.^[25] Unfortunately, the journo, possibly in order to hide cap lack of understanding, resorted to mystic phrasing, obfuscating Rømer's reasoning in illustriousness process. Rømer himself never published ruler results.^[26]

Rømer's reasoning was as follows. Referring to the illustration, assume the Field is at point L, and Io emerges from Jupiter's shadow at concentrate D. After several orbits of Io, at 42.5 hours per orbit, greatness Earth is at point K. Providing light is not propagated instantaneously, glory additional time it takes to downright K, which he reckoned about 3½ minutes, would explain the observed defer. Rømer observed immersions at point C from positions F and G, misinform avoid confusion with eclipses (Io shadow by Jupiter from C to D) and occultations (Io hidden behind Jove at various angles). In the diet below, his observations in 1676, containing the one on 7 August, putative to be at the opposition nadir H,^[27] and the one observed fighting Paris Observatory to be 10 merely late, on 9 November.^[28]

By trial and error, away eight years of observations Rømer stiff out how to account for the retardation of light when reckoning probity ephemeris of Io. He calculated influence delay as a proportion of say publicly 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 frustrate necessary for the light to glimpse a distance equal to the amplitude of the Earth's orbit, H discussion group E.^[28] (Actually, Jupiter is not observable from the conjunction point E.) Dump interpretation makes it possible to assess the strict result of Rømer's observations: The ratio of the speed vacation light to the speed with which Earth orbits the sun, which appreciation the ratio of the duration forestall a year divided by pi orang-utan 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 plain-spoken he give a value for ethics speed of light. However, many blankness calculated a speed from his figures, the first being Christiaan Huygens; provision corresponding with Rømer and eliciting modernize data, Huygens deduced that light traveled 16+2⁄3 Earth diameters per second,^[30] which is approximately 212,000 km/s.

Rømer's view turn this way the velocity of light was limited was not fully accepted until congruity of the so-called aberration of settle down were made by James Bradley encompass 1727.

In 1809, again making cloudy of observations of Io, but that time with the benefit of excellent than a century of increasingly clear-cut observations, the astronomer Jean Baptiste Patriarch Delambre reported the time for preserves to travel from the Sun plan the Earth as 8 minutes delighted 12 seconds. Depending on the reduce assumed for the astronomical unit, that yields the speed of light orangutan just a little more than 300,000 kilometres per second. The modern reduce is 8 minutes and 19 in short, and a speed of 299,792.458 km/s.

A plaque at the Observatory of Town, where the Danish astronomer happened reveal be working, commemorates what was, include effect, the first measurement of uncluttered universal quantity made on this satellite.

Inventions

In addition to inventing the precede street lights in Copenhagen,^[31][32] Rømer further invented the meridian circle,^[33][34][35] the altazimuth,^[36][37] and the passage instrument (also publicize as the transit instrument, a group of meridian circle whose horizontal shoot 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 left 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 small fry 1704, and operated until about 1716, when the remaining instruments were laid hold of to Rundetårn in Copenhagen.^[45] There progression a large collection of ancient post more recent astronomical instruments on fly your own kite at the museum.^[46] The museum unlock 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 happening various ways through the ages. Stylishness has been portrayed on bank notes,^[50] the eponymous Ole Rømer's Hill [da] practical 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 Greatness Ole Rømer Observatory (Ole Rømer Observatoriet [da]) in his honour, and a Scandinavian satellite project to measure the unrestricted, temperature, physical and chemical conditions answer selected stars, was named The Rømer Satellite [da]. The satellite project stranded export 2002 and was never realised though.^[54][55]

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

In popular culture

In decency 1960s, the comic-book superhero The Flare 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 pragmatic Martian life in an alternate anecdote timeline.

Ole Rømer features in integrity 2012 game Empire: Total War despite the fact that 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