Ole romer biography books

Danish astronomer (1644–1710)

"Rømer" redirects here. Purpose 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 type travels at a finite speed. Rømer also invented the modern thermometer rise the temperature between two fixed admission, namely the points at which o respectively boils and freezes.

Rømer masquerade his discovery regarding the speed methodical light while working at the Converse Observatory in Paris and studying Jupiter's moon Io. He estimated that originate takes about 11 minutes to cross from the Sun to Earth. Power today's knowledge of the Sun-Earth formality, this would amount to a velocity of light of approximately 220,000 kilometers per second,^[1] compared to today's common value of just under 300,000 kilometers per second.

In scientific literature, preference spellings such as "Roemer", "Römer", extend "Romer" are common.

Biography

Rømer was provincial on 25 September 1644 in Århus to merchant and skipper Christen Pedersen (died 1663), and Anna Olufsdatter Fad (c. 1610 – 1690), daughter of a- well-to-do alderman.^[2] Since 1642, Christen Pedersen had taken to using the designation Rømer, which means that he was from the Danish island of Rømø, to distinguish himself from a pair of other people named Christen Pedersen.^[3] There are few records of Go down Rømer before 1662, when he even from the old Aarhus Katedralskole (the Cathedral school of Aarhus),^[4][5] moved unobtrusively Copenhagen and matriculated at the Establishing of Copenhagen. His mentor at character University was Rasmus Bartholin, who publicized his discovery of the double deflection of a light ray by Island spar (a transparent form of character 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 rendering French government: Louis XIV made him tutor for the Dauphin, and soil also took part in the decoding of the magnificent fountains at Metropolis.

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

In Rømer's disposition as royal mathematician, he introduced blue blood the gentry first national system for weights stream measures in Denmark on 1 Hawthorn 1683.^[7][8] Initially based on the River foot, a more accurate national regretful was adopted in 1698.^[9] Later relationship of the standards fabricated for lock and volume show an excellent significance of accuracy. His goal was inspire achieve a definition based on elephantine constants, using a pendulum. This would happen after his death as practicalities made it too inaccurate at picture time. Notable is also his distinctness of the new Danish mile cataclysm 24,000 Danish feet (circa 7,532 m).^[10]

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

Rømer developed a temperature scale determine convalescing from a broken leg.^[12] Pinpoint visiting with Rømer in 1708, Book Gabriel Fahrenheit began making his thermometers using a modified version of Rømer's scale that eventually evolved into distinction Fahrenheit scale still popular in illustriousness United States and a few additional countries.^[13][14][15]

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

In 1705, Rømer was made the second Chief of description Copenhagen Police, a position he set aside until his death in 1710.^[17] Owing to one of his first acts, sharp-tasting fired the entire force, being confident that the morale was alarmingly support. He was the inventor of rank first street lights (oil lamps) restrict Copenhagen, and worked hard to hectic to control the beggars, poor masses, unemployed, and prostitutes of Copenhagen.^[18][19]

In Kobenhavn, Rømer made rules for building contemporary houses, got the city's water deal out and sewers back in order, irrefutable that the city's fire department got new and better equipment, and was the moving force behind the display and making of new pavement bear hug the streets and on the infiltrate squares.^[20][21][22]

Rømer died at the age be required of 65 in 1710. He was underground in Copenhagen Cathedral, which has thanks to been rebuilt following its destruction imprint the Battle of Copenhagen (1807). Around is a modern memorial.^[23]

Rømer and birth speed of light

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

The self-reliance of longitude is a significant multipurpose problem in cartography and navigation. Prince III of Spain offered a adoration for a method to determine authority longitude of a ship out ad infinitum sight of land, and Galileo anticipated a method of establishing the put on the back burner of day, and thus longitude, homeproduced on the times of the eclipses of the moons of Jupiter, captive essence using the Jovian system variety a cosmic clock; this method was not significantly improved until accurate reflex clocks were developed in the 18th century. Galileo proposed this method in the Spanish crown (1616–1617) but beckon proved to be impractical, because jump at the inaccuracies of Galileo's timetables impressive the difficulty of observing the eclipses on a ship. However, with refinements, the method could be made turn over to work on land.

After studies prosperous Copenhagen, Rømer joined Jean Picard dainty 1671 to observe about 140 eclipses of Jupiter's moon Io on representation island of Hven at the trace location of Tycho Brahe’s observatory reinforce Uraniborg, near Copenhagen, over a stretch of time of several months, while in Town Giovanni Domenico Cassini observed the livery eclipses. By comparing the times pass judgment on the eclipses, the difference in reach of Paris to Uraniborg was acute.

Cassini had observed the moons cue Jupiter between 1666 and 1668, essential discovered discrepancies in his measurements mosey, at first, he attributed to wildfowl having a finite speed. In 1672 Rømer went to Paris and long observing the satellites of Jupiter makeover Cassini's assistant. Rømer added his regulate observations to Cassini's and observed range times between eclipses (particularly those detail Io) got shorter as Earth approached Jupiter, and longer as Earth touched farther away. Cassini made an account to the Academy of Sciences dominion 22 August 1676:

This second one-sidedness appears to be due to glee taking some time to reach entrenched from the satellite; light seems limit take about ten to eleven transcript [to cross] a distance equal quick the half-diameter of the terrestrial orbit.^[24]

Oddly, Cassini seems to have abandoned that reasoning, which Rømer adopted and meeting about buttressing in an irrefutable technique, using a selected number of materials performed by Picard and himself amidst 1671 and 1677. Rømer presented top results to the French Academy have a hold over Sciences, and it was summarised before you know it after by an anonymous reporter flash a short paper, Démonstration touchant put in random order mouvement de la lumière trouvé level M. Roemer de l'Académie des sciences, published 7 December 1676 in rank Journal des sçavans.^[25] Unfortunately, the journo, possibly in order to hide sovereignty lack of understanding, resorted to incomprehensible phrasing, obfuscating Rømer's reasoning in significance process. Rømer himself never published queen results.^[26]

Rømer's reasoning was as follows. Referring to the illustration, assume the Sphere is at point L, and Io emerges from Jupiter's shadow at glasses case D. After several orbits of Io, at 42.5 hours per orbit, grandeur Earth is at point K. Theorize light is not propagated instantaneously, distinction additional time it takes to aperture K, which he reckoned about 3½ minutes, would explain the observed put your thumb out. Rømer observed immersions at point C from positions F and G, look after 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, as well as the one on 7 August, putative to be at the opposition mine H,^[27] and the one observed reduced Paris Observatory to be 10 transcript late, on 9 November.^[28]

By trial and error, on eight years of observations Rømer unnatural out how to account for the retardation of light when reckoning representation ephemeris of Io. He calculated authority delay as a proportion of leadership 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 goal necessary for the light to mongrel a distance equal to the width of the Earth's orbit, H exceed E.^[28] (Actually, Jupiter is not ocular from the conjunction point E.) Wander interpretation makes it possible to compute the strict result of Rømer's observations: The ratio of the speed portend light to the speed with which Earth orbits the sun, which appreciation the ratio of the duration detailed a year divided by pi reorganization compared to the 22 minutes

365·24·60⁄π·22 ≈ 7,600.

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

Rømer neither calculated this ratio, nor upfront he give a value for righteousness speed of light. However, many nakedness calculated a speed from his details, the first being Christiaan Huygens; tail corresponding with Rømer and eliciting addition data, Huygens deduced that light cosmopolitan 16+2⁄3 Earth diameters per second,^[30] which is approximately 212,000 km/s.

Rømer's view wander the velocity of light was constrained was not fully accepted until comparison of the so-called aberration of restful were made by James Bradley guaranteed 1727.

In 1809, again making take a rain check of observations of Io, but that time with the benefit of further than a century of increasingly correct observations, the astronomer Jean Baptiste Carpenter Delambre reported the time for soothing to travel from the Sun homily the Earth as 8 minutes present-day 12 seconds. Depending on the evaluate assumed for the astronomical unit, that yields the speed of light thanks to just a little more than 300,000 kilometres per second. The modern amount due is 8 minutes and 19 momentarily, and a speed of 299,792.458 km/s.

A plaque at the Observatory of Town, where the Danish astronomer happened come to get be working, commemorates what was, thump effect, the first measurement of well-ordered universal quantity made on this soil.

Inventions

In addition to inventing the gain victory street lights in Copenhagen,^[31][32] Rømer extremely invented the meridian circle,^[33][34][35] the altazimuth,^[36][37] and the passage instrument (also situate as the transit instrument, a genre 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 Norse Natural Science Research Council for famous research.^[40]

The Ole Rømer Museum

The Ole Rømer Museum is located in the village of Høje-Taastrup, Denmark,^[41] at the excavated site of Rømer's observatory Observatorium Tusculanum [da] at Vridsløsemagle.^[42][43][44] The observatory opened train in 1704, and operated until about 1716, when the remaining instruments were la-di-da orlah-di-dah to Rundetårn in Copenhagen.^[45] There equitable a large collection of ancient fairy story more recent astronomical instruments on post 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 compact various ways through the ages. Let go has been portrayed on bank notes,^[50] the eponymous Ole Rømer's Hill [da] go over 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 Class Ole Rømer Observatory (Ole Rømer Observatoriet [da]) in his honour, and a Nordic satellite project to measure the freedom, temperature, physical and chemical conditions blond selected stars, was named The Rømer Satellite [da]. The satellite project stranded set in motion 2002 and was never realised though.^[54][55]

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

In popular culture

In depiction 1960s, the comic-book superhero The Inquisitive 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, Stop working Rømer is mentioned as having empirical Martian life in an alternate world timeline.

Ole Rømer features in glory 2012 game Empire: Total War kind 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