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Superfluid Helium
Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling and melting point are the lowest among all the elements. It is the second lightest and second most abundant element in the observable universe (hydrogen is the lightest and most abundant). It is present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to this in both the Sun and in Jupiter, due to the very high nuclear binding energy (per nucleon) of helium-4, with respect to the next three elements after helium. This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay. The most common isotope of helium in the universe is helium-4, the vast majority of which was formed during the Big B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helios
In ancient Greek religion and mythology, Helios (; grc, , , Sun; Homeric Greek: ) is the god and personification of the Sun (Solar deity). His name is also Latinized as Helius, and he is often given the epithets Hyperion ("the one above") and Phaethon ("the shining"). Helios is often depicted in art with a radiant crown and driving a horse-drawn chariot through the sky. He was a guardian of oaths and also the god of sight. Though Helios was a relatively minor deity in Classical Greece, his worship grew more prominent in late antiquity thanks to his identification with several major solar divinities of the Roman period, particularly Apollo and Sol. The Roman Emperor Julian made Helios the central divinity of his short-lived revival of traditional Roman religious practices in the 4th century AD. Helios figures prominently in several works of Greek mythology, poetry, and literature, in which he is often described as the son of the Titans Hyperion and Theia and brother of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helium-4
Helium-4 () is a stable isotope of the element helium. It is by far the more abundant of the two naturally occurring isotopes of helium, making up about 99.99986% of the helium on Earth. Its nucleus is identical to an alpha particle, and consists of two protons and two neutrons. Alpha decay of heavy elements in the Earth's crust is the source of most naturally occurring helium-4 on Earth, produced after the planet cooled and solidified. While it is also produced by nuclear fusion in stars, most helium-4 in the Sun and in the universe is thought to have been produced by the Big Bang, and is referred to as " primordial helium". However, primordial helium-4 is largely absent from the Earth, having escaped during the high-temperature phase of Earth's formation. Helium-4 makes up about one quarter of the ordinary matter in the universe by mass, with almost all of the rest being hydrogen. When liquid helium-4 is cooled to below , it becomes a superfluid, with properties that are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nils Abraham Langlet
Nils Abraham Langlet (9 July 1868 – 30 March 1936; known by his second given name) was a Swedish chemist. Biography Langlet was born in Södertälje, Sweden. He was the son of architect Emil Victor Langlet (1824–1898) and his wife, author Clara Mathilda Ulrika Clementine Söderén (1832–1904). His brothers included author Valdemar Langlet (1872–1960). From 1886 to 1896, he studied chemistry under Per Teodor Cleve (1840–1905) at Uppsala University, where he became a philosophy graduate in 1888, Philosophy Licentiate in 1893 and obtained a doctorate in 1896 and was made '' docent'' in the same year. In 1899, he became lecturer in Chemistry and Chemical Technology at the Chalmers University of Technology in Gothenburg, where he received a professorship in the same field in 1911. From 1926, when his professorship was divided, he was professor of Organic Chemistry. In 1895, while working with Cleve in Uppsala, he made the independent discovery of the element helium (in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Per Teodor Cleve
Per Teodor Cleve (10 February 1840 – 18 June 1905) was a Swedish chemist, biologist, mineralogist and oceanographer. He is best known for his discovery of the chemical elements holmium and thulium. Born in Stockholm in 1840, Cleve earned his BSc and PhD from Uppsala University in 1863 and 1868, respectively. After receiving his PhD, he became an assistant professor of chemistry at the university. He later became professor of general and agricultural chemistry. In 1874 he theorised that didymium was in fact two elements; this theory was confirmed in 1885 when Carl Auer von Welsbach discovered neodymium and praseodymium. In 1879 Cleve discovered holmium and thulium. His other contributions to chemistry include the discovery of aminonaphthalenesulfonic acids, also known as Cleve's acids. From 1890 on he focused on biological studies. He developed a method of determining the age and order of late glacial and postglacial deposits from the types of diatom fossils in the deposits, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sir William Ramsay
Sir William Ramsay (; 2 October 1852 – 23 July 1916) was a Scottish chemist who discovered the noble gases and received the Nobel Prize in Chemistry in 1904 "in recognition of his services in the discovery of the inert gaseous elements in air" along with his collaborator, John William Strutt, 3rd Baron Rayleigh, who received the Nobel Prize in Physics that same year for their discovery of argon. After the two men identified argon, Ramsay investigated other atmospheric gases. His work in isolating argon, helium, neon, krypton, and xenon led to the development of a new section of the periodic table. Early years Ramsay was born at 2 Clifton StreetGlasgow Post Office Directory 1852 in Glasgow on 2 October 1852, the son of civil engineer and surveyor, William C. Ramsay, and his wife, Catherine Robertson. The family lived at 2 Clifton Street in the city centre, a three-storey and basement Georgian townhouse. The family moved to 1 Oakvale Place in the Hillhead district in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discovery Of The Chemical Elements
The discovery of the 118 chemical elements known to exist as of 2022 is presented in chronological order. The elements are listed generally in the order in which each was first defined as the pure element, as the exact date of discovery of most elements cannot be accurately determined. There are plans to synthesize more elements, and it is not known how many elements are possible. Each element's name, atomic number, year of first report, name of the discoverer, and notes related to the discovery are listed. Periodic table of elements Ancient discoveries Modern discoveries Graphics See also * History of the periodic table * Periodic table * Extended periodic table * ''The Mystery of Matter: Search for the Elements'' (2014/2015 PBS film) * Transfermium Wars References External linksHistory of the Origin of the Chemical Elements and Their DiscoverersLast updated by Boris Pritychenko on March 30, 2004 [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norman Lockyer
Sir Joseph Norman Lockyer (17 May 1836 – 16 August 1920) was an English scientist and astronomer. Along with the French scientist Pierre Janssen, he is credited with discovering the gas helium. Lockyer also is remembered for being the founder and first editor of the influential journal ''Nature''. Biography Lockyer was born in Rugby, Warwickshire. His early introduction to science was through his father, who was a pioneer of the electric telegraph. After a conventional schooling supplemented by travel in Switzerland and France, he worked for some years as a civil servant in the British War Office. He settled in Wimbledon, South London after marrying Winifred James, who helped translate at least four French scientific works into English. He was a keen amateur astronomer with a particular interest in the Sun. In 1885 he became the world's first professor of astronomical physics at the Royal College of Science, South Kensington, now part of Imperial College. At the coll ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre Janssen
Pierre Jules César Janssen (22 February 1824 – 23 December 1907), usually known as Jules Janssen, was a French astronomer who, along with English scientist Joseph Norman Lockyer, is credited with discovering the gaseous nature of the solar chromosphere, and with some justification the element helium. Life, work, and interests Janssen was born in Paris into a cultivated family. His father, Antoine César Janssen (born in Paris, 1780 – 1860) was a well known clarinettist from Dutch/Belgian descent (his father emigrated from Walloon Brabant to Paris). His mother Pauline Marie Le Moyne (1789 – 1871) was a daughter of the architect Paul Guillaume Le Moyne. Pierre Janssen studied mathematics and physics at the faculty of sciences. He taught at the Lycée Charlemagne in 1853, and in the school of architecture 1865 – 1871, but his energies were mainly devoted to various scientific missions entrusted to him. Thus in 1857 he went to Peru in order to determine the magnetic equa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Georges Rayet
Georges-Antoine-Pons Rayet (12 December 1839 – 14 June 1906) was a French astronomer. He was born in Bordeaux, France. He began working at the Paris Observatory in 1863. He worked on meteorology in addition to astronomy. He specialized in what was then the new field of spectroscopy. He was founder and director of the Bordeaux Observatory for more than 25 years until his death. He discovered Wolf–Rayet star Wolf–Rayet stars, often abbreviated as WR stars, are a rare heterogeneous set of stars with unusual spectra showing prominent broad emission lines of ionised helium and highly ionised nitrogen or carbon. The spectra indicate very high surface ...s together with Charles Wolf in 1867. Awarded the Janssen Medal from the French Academy of Sciences in 1891. Obituaries AN 172 (1906) 111//112(in French) (one paragraph) (one sentence) External links {{DEFAULTSORT:Rayet, Georges 1839 births 1906 deaths 19th-century French astronomers École Normale Supé ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar Eclipse Of August 18, 1868
A total solar eclipse occurred on August 18, 1868, also known as "The King of Siam's eclipse". A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. A total solar eclipse occurs when the Moon's apparent diameter is larger than the Sun's, blocking all direct sunlight, turning day into darkness. Totality occurs in a narrow path across Earth's surface, with the partial solar eclipse visible over a surrounding region thousands of kilometres wide. Observations Solar eclipse 1868Aug18-Bullock.png, Bullock sketch of the eclipse, ''Total Eclipses of the Sun'', 1900. Sketches of the total solar eclipse, 1868 (19745966082).jpg, M. Stephan sketches of the eclipse, ''Archives des missions scientifiques et littéraires'', 1868. Map of the solar eclipse of August 18, 1868 (19757912091).jpg, Map of the forecast path of the total eclipse, ''Archives des missions scientifiques et littéraires'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectral Line
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules. These "fingerprints" can be compared to the previously collected ones of atoms and molecules, and are thus used to identify the atomic and molecular components of stars and planets, which would otherwise be impossible. Types of line spectra Spectral lines are the result of interaction between a quantum system (usually atoms, but sometimes molecules or atomic nuclei) and a single photon. When a photon has about the right amount of energy (which is connected to its frequency) to allow a change in the energy state of the system (in the case of an atom this is usually an electron changing orbitals), the photon is absorbed. Then the energy will be spontaneously re-emitted, either as one photon at the same frequ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stars
A star is an astronomical object comprising a luminous spheroid of plasma held together by its gravity. The nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night, but their immense distances from Earth make them appear as fixed points of light. The most prominent stars have been categorised into constellations and asterisms, and many of the brightest stars have proper names. Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. The observable universe contains an estimated to stars. Only about 4,000 of these stars are visible to the naked eye, all within the Milky Way galaxy. A star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Its total mass is the main factor determining its evolution and eventual fate. A star shines for most of its active life du ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
