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Arjen Roelofs
Arjen Roelofs (1 March 1754 – 11 May 1828) was a Dutch astronomer. Early life Roelofs was born on the Hommema-sate (estate) near Hijum in Friesland, the youngest of four sons and two daughters. His father was Roelof Pytters, a tenant farmer and tax receiver. His mother was Neeltje Alberts from Finkum. The oldest son Klaas trained as a steersman, but did not work as one, and instead became a doctor in Sexbierum. The other sister Lisbeth married and left the household. It was not an easy life on the farm, but this is where the other three boys, Pieter, Albert and Arjen worked. Their mother stimulated the interest of the three sons in mathematics and science, however their father was unhappy with this. After their parents died in 1790, the three brothers took over the farm, and their sister Antje became their housekeeper. None of these four ever married, and they all lived on the farm until they died. Arjen Roelofs was supposed to have polio so he could not use his right le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, galaxies – in either observational astronomy, observational (by analyzing the data) or theoretical astronomy. Examples of topics or fields astronomers study include planetary science, Sun, solar astronomy, the Star formation, origin or stellar evolution, evolution of stars, or the galaxy formation and evolution, formation of galaxies. A related but distinct subject is physical cosmology, which studies the Universe as a whole. Types Astronomers usually fall under either of two main types: observational astronomy, observational and theoretical astronomy, theoretical. Observational astronomers make direct observations of Astronomical object, celestial objects and analyze the data. In contrast, theoretical astronomers create and investigate C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jean Henri Van Swinden
Jean Henri van Swinden (The Hague, 8 June 1746 – Amsterdam, 9 March 1823) was a Dutch mathematician and physicist who taught in Franeker and Amsterdam. Biography His parents were the lawyer Phillippe van Swinden and Marie Anne Tollosan. He was trained 1763-1766 at the University of Leiden, where he became doctor of philosophy on 12 June 1766 with the thesis "Natural power of attraction". He became professor at the University of Franeker the same year, where he continued to study and conduct research as well as teach. In 1776 he won a prize from the Académie Royale des Sciences along with Charles-Augustin de Coulomb for his work on earth's magnetic field, and the relationship between magnetism and electricity. A year later he won a prize from the Bavarian Academy of Sciences and Humanities. His description of Eise Eisinga's planetarium in 1780 was later republished. In 1785 he moved to Amsterdam where he became professor at the Athenaeum Illustre of Amsterdam. There he was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lightning
Lightning is a naturally occurring electrostatic discharge during which two electric charge, electrically charged regions, both in the atmosphere or with one on the land, ground, temporarily neutralize themselves, causing the instantaneous release of an average of one Joule, gigajoule of energy. This discharge may produce a wide range of electromagnetic radiation, from heat created by the rapid movement of electrons, to brilliant flashes of visible light in the form of black-body radiation. Lightning causes thunder, a sound from the shock wave which develops as gases in the vicinity of the discharge experience a sudden increase in pressure. Lightning occurs commonly during thunderstorms as well as other types of energetic weather systems, but volcanic lightning can also occur during volcanic eruptions. The three main kinds of lightning are distinguished by where they occur: either inside a single Cumulonimbus cloud, thundercloud (intra-cloud), between two clouds (cloud-to-cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dike (construction)
A levee (), dike ( American English), dyke ( Commonwealth English), embankment, floodbank, or stop bank is a structure that is usually earthen and that often runs parallel to the course of a river in its floodplain or along low-lying coastlines. The purpose of a levee is to keep the course of rivers from changing and to protect against flooding of the area adjoining the river or coast. Levees can be naturally occurring ridge structures that form next to the bank of a river, or be an artificially constructed fill or wall that regulates water levels. Ancient civilizations in the Indus Valley, ancient Egypt, Mesopotamia and China all built levees. Today, levees can be found around the world, and failures of levees due to erosion or other causes can be major disasters. Etymology Speakers of American English (notably in the Midwest and Deep South) use the word ''levee'', from the French word (from the feminine past participle of the French verb , 'to raise'). It ori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lightning Conductor
A lightning rod or lightning conductor (British English) is a metal rod mounted on a structure and intended to protect the structure from a lightning strike. If lightning hits the structure, it will preferentially strike the rod and be conducted to ground through a wire, instead of passing through the structure, where it could start a fire or cause electrocution. Lightning rods are also called finials, air terminals, or strike termination devices. In a lightning protection system, a lightning rod is a single component of the system. The lightning rod requires a connection to earth to perform its protective function. Lightning rods come in many different forms, including hollow, solid, pointed, rounded, flat strips, or even bristle brush-like. The main attribute common to all lightning rods is that they are all made of conductive materials, such as copper and aluminum. Copper and its alloys are the most common materials used in lightning protection. History The principle of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transit Of Mercury
frameless, upright=0.5 A transit of Mercury across the Sun takes place when the planet Mercury passes directly between the Sun and a superior planet. During a transit, Mercury appears as a tiny black dot moving across the Sun as the planet obscures a small portion of the solar disk. Because of orbital alignments, transits viewed from Earth occur in May or November. The last four such transits occurred on May 7, 2003; November 8, 2006; May 9, 2016; and November 11, 2019. The next will occur on November 13, 2032. A typical transit lasts several hours. Mercury transits are much more frequent than transits of Venus, with about 13 or 14 per century, primarily because Mercury is closer to the Sun and orbits it more rapidly. On June 3, 2014, the Mars rover ''Curiosity'' observed the planet Mercury transiting the Sun, marking the first time a planetary transit has been observed from a celestial body besides Earth. Scientific investigation The orbit of the planet Mercury lies interi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Eclipse
A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby obscuring the view of the Sun from a small part of the Earth, totally or partially. Such an alignment occurs during an eclipse season, approximately every six months, during the new moon phase, when the Moon's orbital plane is closest to the plane of the Earth's orbit. In a total eclipse, the disk of the Sun is fully obscured by the Moon. In partial and annular eclipses, only part of the Sun is obscured. Unlike a lunar eclipse, which may be viewed from anywhere on the night side of Earth, a solar eclipse can only be viewed from a relatively small area of the world. As such, although total solar eclipses occur somewhere on Earth every 18 months on average, they recur at any given place only once every 360 to 410 years. If the Moon were in a perfectly circular orbit and in the same orbital plane as Earth, there would be total solar eclipses once a month, at every new moon. Instead, because the Moon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Utrecht (city)
Utrecht ( , , ) is the fourth-largest city and a municipality of the Netherlands, capital and most populous city of the province of Utrecht. It is located in the eastern corner of the Randstad conurbation, in the very centre of mainland Netherlands, about 35 km south east of the capital Amsterdam and 45 km north east of Rotterdam. It has a population of 361,966 as of 1 December 2021. Utrecht's ancient city centre features many buildings and structures, several dating as far back as the High Middle Ages. It has been the religious centre of the Netherlands since the 8th century. It was the most important city in the Netherlands until the Dutch Golden Age, when it was surpassed by Amsterdam as the country's cultural centre and most populous city. Utrecht is home to Utrecht University, the largest university in the Netherlands, as well as several other institutions of higher education. Due to its central position within the country, it is an important hub for both rail and road ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leiden
Leiden (; in English and archaic Dutch also Leyden) is a city and municipality in the province of South Holland, Netherlands. The municipality of Leiden has a population of 119,713, but the city forms one densely connected agglomeration with its suburbs Oegstgeest, Leiderdorp, Voorschoten and Zoeterwoude with 206,647 inhabitants. The Netherlands Central Bureau of Statistics (CBS) further includes Katwijk in the agglomeration which makes the total population of the Leiden urban agglomeration 270,879, and in the larger Leiden urban area also Teylingen, Noordwijk, and Noordwijkerhout are included with in total 348,868 inhabitants. Leiden is located on the Oude Rijn, at a distance of some from The Hague to its south and some from Amsterdam to its north. The recreational area of the Kaag Lakes (Kagerplassen) lies just to the northeast of Leiden. A university city since 1575, Leiden has been one of Europe's most prominent scientific centres for more than four centuries. Leide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Louis Bonaparte
Louis Napoléon Bonaparte (born Luigi Buonaparte; 2 September 1778 – 25 July 1846) was a younger brother of Napoleon I, Emperor of the French. He was a monarch in his own right from 1806 to 1810, ruling over the Kingdom of Holland (a French client state roughly corresponding to the current Netherlands). In that capacity he was known as Louis I (Dutch: Lodewijk I ). Louis was the fifth surviving child and fourth surviving son of Carlo Buonaparte and Letizia Ramolino, out of eight children who lived past infancy. He and his siblings were all born on Corsica, which had been conquered by France less than a decade before his birth. Louis followed his older brothers into the French Army, where he benefited from Napoleon's patronage. In 1802, he married his step-niece Hortense de Beauharnais, the daughter of Empress Joséphine (Napoleon's wife). In 1806, Napoleon established the Kingdom of Holland in place of the Batavian Republic, appointing Louis as the new king. Napoleon had i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Order Of The Netherlands Lion
The Order of the Netherlands Lion, also known as the Order of the Lion of the Netherlands ( nl, De Orde van de Nederlandse Leeuw, french: L'Ordre du Lion Néerlandais) is a Dutch order of chivalry founded by King William I of the Netherlands on 29 September 1815. The Order of the Netherlands Lion was until recently awarded to eminent individuals from all walks of life, including generals, ministers of the crown, mayors of large towns, professors and leading scientists, industrialists, high-ranking civil servants, presiding judges and renowned artists. Since 1980 the Order has been primarily used to recognise merit in the arts, science, sport and literature; others are awarded the Order of Orange-Nassau. Appointment to the grade of Commander (see below) is very rare (Nobel Prizewinners; the conductor Bernard Haitink towards the end of his life, and the dancer and choreographer Hans van Manen, for example). The Order ranks after the Military William Order, which is only awarded for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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