Rikunarita-ORG/Wikinium huggingface dataset:
# Fahrenheit

| Fahrenheit |
| --- |
| Thermometer with Fahrenheit and Celsius. |
| General information |
| Unit system | Imperial/US customary |
| Unit of | Temperature |
| Symbol | °F  |
| Named after | Daniel Gabriel Fahrenheit |
| Conversions |
| *x °F in ...* | *... is equal to ...* |
|  |
|    °C |     WIKINIUM\_MATH\_PH\_0 °C |

**Fahrenheit** (more precisely, a **degree Fahrenheit**) is a unit of measurement that is used to measure temperature. The conversion rate to degrees Celsius is C= 5/9 x (F − 32). The unit is abbreviated °F.

## History

This temperature scale was made in 1724 by a German scientist named Daniel Gabriel Fahrenheit. In the 20th century, the unit became less used, and the degree Celsius more used. Fahrenheit is still often used in the United States. Fahrenheit is still used on some websites and on weather forecasts in the United Kingdom mainly since the older population is more familiar with it than with Celsius.

Fahrenheit is considered by many to be an old-fashioned and outdated way of measuring temperature and has been largely replaced with Celsius.

Overall, the use of Fahrenheit is in decline throughout most of the world, with the US being the main exception.

## Examples

* Water freezes at 32 °F and boils at 212 °F.
* Room temperature is about 70 °F.
* A human's body temperature is usually close to 98.6 °F.
* Absolute zero is –459.67 °F.

## Related pages

* Celsius
* Kelvin
* Rankine
* Delisle
* Newton (unit) (force)
* Réaumur
* Rømer
# Type Ia supernova

A **type Ia supernova** is a type of supernova that occurs in binary systems (two stars orbiting one another) in which one of the stars is a white dwarf. The other star can be anything from a giant star to an even smaller white dwarf. Physically, carbon-oxygen white dwarfs with slow rotation are limited to below 1.44 solar masses.

Since type Ia supernovae have a known brightness they can be used as standard candles to determine the distance to a galaxy once the stretch-factor is accounted for.

When a runaway thermonuclear explosion rips through a white dwarf star and blows the star to bits, it is called a type 1a supernova. These explosions are incredibly violent and incredibly bright, sometimes outshining entire galaxies.

Type I (especially Ia) supernova create most of the iron and nickel found in the interstellar medium. Type 1a supernovae are several times more luminous than type Ib, Ic, and type II supernovae. They leave no core remnant behind, and happen when a low-mass star's core remnant (a white dwarf) detonates.
# Googolplex

A **googolplex** is the number 10googol, equivalent to 1010100 or 10Ten duotrigintillion or 1010,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000.

Like the number *googol*, *googolplex* was thought of by Milton Sirotta, the nephew of mathematician Edward Kasner.

The company Google named their headquarters, the Googleplex, after the number.

A **googolplexplex / goggolplexian / goggolduplex / goggolplexsquared** is a 1 followed by a Googolplex amount of zeros which is 10googolplex (101010100 ).

A **goggolplexianth** is represented as 10^googolplexian

Though thought to be infinite, it has been theorized that with enough computers and enough time, this number could be written.

## Related pages

* Exponent
* Graham's number
* Googol
# Kalam

**Kalām** (Arabic: عِلْمُ الْكَلَامِ, literally "speech" or "words") is the Islamic discipline of seeking theological knowledge through dialectic (debate and argument). It also promotes prudence and logical reasoning. A practitioner of kalām is called a *mutakallim* (plural *mutakallimiin*).

## Related pages

* Islamic theology
# Wolfgang Rindler

| ProfessorWolfgang Rindler |
| --- |
|  |
| Born | (1924-05-18)18 May 1924 Vienna, Austria |
| Died | 8 February 2019(2019-02-08) (aged 94) |
| Education | University of Liverpool Imperial College London |
| Known for | Event Horizon *Essential Relativity* Rindler coordinates |
| **Scientific career** |
| Fields | Physics |
| Institutions | University of Texas at Dallas |
|  |
| Website | www.utdallas.edu/physics/faculty/wolfgang.html |

**Wolfgang Rindler** (18 May 1924 – 8 February 2019) was an Austrian-born American physicist. He worked in the field of General Relativity where he was known for introducing the term "event horizon", Rindler coordinates, and for popularizing the use of spinors in general relativity.

He was an honorary member of the Austrian Academy of Sciences and foreign member of the Accademia delle Scienze di Torino, he was also a prolific textbook author.
# Halley's Comet

Halley's Comet on 8 March 1986
**Halley's Comet** (Comet Halley) is a comet which comes round every 75 or 76 years. When it is near, it can be seen with the naked eye. It will return in 2061.

The comet is named after Edmond Halley (1656–1742), an English astronomer, who predicted the comet's return. Halley's Comet was the first comet to be recognized as periodic. (Periodic means that it comes by Earth regularly.)

When the comet came close to the Earth in 1986, it was visited by several space-probes. The probe *Giotto* from the European Space Agency managed the closest approach to the comet.

The number of years that the comet finishes its full cycle can vary depending on the effect of another planet's gravitational pull.

In 1986, Halley's Comet was the first to be observed in detail by spacecraft. It gave the first data on the structure of a comet nucleus and how the *coma* (nebulous envelope around the core or nucleus) and the tail formed. These observations supported Fred Whipple's "dirty snowball" model. This correctly predicted that Halley would be composed of a mixture of volatile ices – such as water, carbon dioxide, ammonia, – and dust. The missions also adjusted these ideas. For example, it is now known that the *surface* of Halley is mostly dusty, non-volatile materials, and that only a small portion of it is icy.

Coming closer to the Sun again: Since 2023, it is closing the distance between the Sun and itself.

## Related pages

* List of comets
# Sagittarius A*

| Saggitarius A\* |
| --- |
| Saggitarius A\* image by Chandra X-Ray Observatory |
| Observation data |
| Type | Radio source |
| Right ascension |  17h 45m 40.05s |
| Declination | ±−29° 00′ 27.9″ |
| Distance | 25900±1400 light years |
| Constellation | Sagittarius |
| Physical characteristics |
| Notable features | Radio source in the center of the Milky Way |
| Other designations | Sgr A\* |
| See also: Diffuse nebula, Lists of nebulae |
| * v
* t
* e
 |

**Sagittarius A\ (**Sgr A\) is a bright astronomical radio source at the center of the Milky Way. It is in the direction of the constellations Sagittarius and Scorpius.

The radio source is part of a larger astronomical feature known as Sagittarius A. Sagittarius A\* is thought to be a supermassive black hole, like those that are at the centers of most spiral and elliptical galaxies. Observations of the star S2 in orbit around Sagittarius A\* were used to show the presence of the Milky Way's central supermassive black hole. This led to the conclusion that Sagittarius A\* is the site of that black hole. Another star, S8, is orbiting Sagittarius A\* along with many other stars. A star known as S14 has an extremely elliptical orbitand a star named S4716 has an orbital period of only 4 years.

## Related pages

* Sagittarius A
* Sagittarius

## Other websites

 Media related to Sagittarius A\* at Wikimedia Commons
# Apollo asteroids

The **Apollo asteroids** are a group of asteroids near Earth named after 1862 Apollo, the first asteroid of this group to be discovered by Karl Wilhelm Reinmuth. They are asteroids that cross Earth. Some of these asteroids can get very close to the Earth, making them a potential threat to our planet.

Well-known Apollo asteroids include:

| Name | Year | Discoverer |
| --- | --- | --- |
| Chebarkul | 2013 | Impacted Earth |
| 2010 AL30 | 2010 | LINEAR |
| 2009 WM1 | 2009 |  |
| 2009 DD45 | 2009 |  |
| 2008 TC3 | 2008 | Catalina Sky Survey |
| 2007 VK184 | 2007 | Catalina Sky Survey |
| 2007 TU24 | 2007 | Catalina Sky Survey |
| 2007 WD5 | 2007 | Catalina Sky Survey |
| 2006 FV35 | 2006 | Spacewatch |
| 2006 SU49 | 2006 | Spacewatch |
| 2004 XP14 | 2004 | LINEAR |
| 2004 AS1 | 2004 | LINEAR |
| 2002 TD66 | 2002 | LINEAR |
| (137108) 1999 AN10 | 1999 | LINEAR |
| 1998 KY26 | 1998 | Spacewatch |
| 1997 XR2 | 1997 | LINEAR |
| 69230 Hermes | 1937 | Karl Reinmuth |
| (53319) 1999 JM8 | 1999 | LINEAR |
| (52760) 1998 ML14 | 1998 | LINEAR |
| (35396) 1997 XF11 | 1997 | Spacewatch |
| (29075) 1950 DA | 1950 | Carl A. Wirtanen |
| 25143 Itokawa | 1998 | LINEAR |
| 1994 CC | 1994 | Spacewatch |
| 6489 Golevka | 1991 | Eleanor F. Helin |
| 4769 Castalia | 1989 | Eleanor F. Helin |
| 4660 Nereus | 1982 | Eleanor F. Helin |
| 4581 Asclepius | 1989 | Henry E. Holt, Norman G. Thomas |
| 4486 Mithra | 1987 | Eric Elst, Vladimir Shkodrov |
| (4197) 1982 TA | 1982 | Eleanor F. Helin, Eugene Shoemaker |
| 4183 Cuno | 1959 | Cuno Hoffmeister |
| 4179 Toutatis | 1989 | Christian Pollas |
| 4015 Wilson-Harrington   | 1979 | Eleanor F. Helin |
| 3200 Phaethon | 1983 | Simon F. Green, John K. Davies / IRAS |
| 2101 Adonis | 1936 | Eugène Joseph Delporte |
| 2063 Bacchus | 1977 | Charles T. Kowal |
| 1866 Sisyphus | 1972 | Paul Wild |
| 1862 Apollo | 1932 | Karl Reinmuth |
| 1685 Toro | 1948 | Carl A. Wirtanen |
| 1620 Geographos | 1951 | Albert George Wilson, Rudolph Minkowski |
| 1566 Icarus | 1949 | Walter Baade |
# Flare star

A **flare star** is a variable star that becomes very much brighter unpredictably for a few minutes at a time.

Flares happen on flare stars in a similar way to solar flares. They are magnetic disturbances in the atmosphere of stars. The brightness increases across the spectrum, from X rays to radio waves.

The first known flare stars were discovered in 1924, they were V1396 Cygni and AT Microscopii. Still the best-known flare star is UV Ceti, that star was discovered in 1948. Today similar flare stars are classified as UV Ceti type variable stars in variable star catalogs. Flares can happen once every few days or, as in the case of Barnard's Star, much less frequently. Proxima Centauri, the nearest star to the Solar System, is also a flare star.

Most flare stars are dim red dwarfs, although less massive (lighter) brown dwarfs might also be able to flare. The more massive (heavier) RS Canum Venaticorum variables (RS CVn) are also known to flare, but scientists understand that a companion star in a binary system causes these flares. This companion star disturbs the magnetic field. Nine stars similar to the Sun have also been seen to flare. There is a suggestion that this happens for similar reasons to the flares of the RS CVn variables. A companion causes the flares, this companion is a massive planet like the planet Jupiter that orbits the flaring star closely.

## Nearby flare stars

Flare stars are give off relatively little light, but have been found as far away as 1,000 light years from Earth.

### Proxima Centauri

Proxima Centauri is closer to the sun than any other star and is a flare star. Proxima Centauri increases its brightness randomly and magnetic force causes this. Convection creates a magnetic field throughout the matter in Proxima Centauri, and this leads to flaring with a total X-ray output similar to that of the Sun though the sun is much more massive (heavier) than Proxima Centauri.

### Wolf 359

The flare star Wolf 359 is another star relatively near the Solar System in the constellation of Leo and has other names (designations) as well. It is a red dwarf of spectral class M6.5 and emits X-rays. It is a UV Ceti flare star, and flares relatively often.

The mean (average) magnetic field varies significantly during periods of time as short as six hours. By comparison, the magnetic field of the Sun averages 1 G (100 μT), although it can rise as high as 3 kG (0.3 T) in active sunspot regions.

### Barnard's Star

Barnard's Star is the second nearest star system to our sun and scientists suspect it is a flare star.

### TVLM513-46546

TVLM513-46546 is the name scientists give to a flare star with very low mass. This small star is only just heavy enough to count as a red dwarf.
# Seyfert galaxy

The Circinus Galaxy, a Type II Seyfert galaxy
A diagram of an active galactic nucleus. The central black hole is surrounded by an accretion disc, which is surrounded by a torus. The broad line region and narrow line emission region are shown, as well as jets coming out of the nucleus
**Seyfert galaxies** are a type of galaxy. They are named after Carl Seyfert who first described them in 1943.

These galaxies are one of the two main types of active galaxies. The other large group are quasars. Seyfert galaxies have quasar-like nuclei: they are very distant luminous sources of electromagnetic radiation. Their very high surface brightness has spectra with strong, high-ionisation emission lines. However, unlike quasars, their host galaxies are clearly visible.

Seyfert galaxies are about 10% of all galaxies, and are some of the most intensely studied objects in astronomy. They are thought to be powered by the same phenomena as quasars, although they are closer and less luminous than quasars. These galaxies have supermassive black holes at their centers which are surrounded by accretion discs of in-falling material. The accretion discs are believed to be the source of the observed ultraviolet radiation. Ultraviolet emission lines and absorption lines are the best way to analyse the surrounding material.

Seen in visible light, most Seyfert galaxies look like normal spiral galaxies. However, when studied under other wavelengths, it becomes clear that the luminosity of their cores is as big as the luminosity of whole galaxies the size of the Milky Way.

## Examples

Seyfert galaxy Messier 51
Seyfert galaxy Messier 87
Seyfert galaxy Centaurus A
Here are some notable examples of Seyfert galaxies:

* Circinus galaxy has rings of gas ejected from its center
* Centaurus A, apparently the brightest Seyfert galaxy as seen from Earth. It is a giant elliptical galaxy: a radio galaxy notable for its relativistic jet spanning more than a million light years in length.
* Messier 51a (NGC 5194), the Whirlpool Galaxy, one of the best known galaxies in the sky.
* Messier 81 (NGC 3031), a popular target for amateur astronomy and the second brightest Seyfert galaxy in the sky after Centaurus A
* Messier 87 (NGC 4486), central galaxy of the Virgo Cluster and the biggest galaxy in the Local Supercluster. It is a radio galaxy notable for its 4,400 light-year long relativistic jet powered by an immense supermassive black hole with the mass of (3.5 ± 0.2)-6.3 billion solar masses
* NGC 1672 has a nucleus engulfed by intense starburst regions
# Diesel locomotive

A British Rail Class 47 diesel locomotive
Former diesel locomotive in Kenya
A **diesel locomotive** is a locomotive powered by a diesel engine. The diesel engine drives the locomotive's wheels through a transmission system. Diesel locomotives are very popular worldwide, due to their ease of use and reliability. They can be more powerful than steam locomotives and do not need an expensive power grid like electric locomotives.

In the 1930s they were often used for runs of very short distances. After the middle 20th century they became the most common kind for long runs, too.

## Transmission systems

* Mechanical transmission uses a gearbox, shaft or chain (diesel-mechanical).
* Electric transmission works by generating electricity which is in turn used to power the wheels (diesel-electric). This is the kind most used.
* Hydraulic transmission uses a hydraulic transmission system (diesel-hydraulic).
# River Severn

| River Severn Welsh: *Afon Hafren* |
| --- |
| The river seen from Shrewsbury Castle |
| Tributaries (light blue) and major settlements on and near the Severn (bold blue) |
| Location |
| Country | England and Wales |
| Region | Mid Wales, West Midlands, South West |
| Counties | Powys, Shropshire, Worcestershire, Gloucestershire |
| Cities | Shrewsbury, Worcester, Gloucester, Bristol |
| Physical characteristics |
|  |
| Source |   |
|  - location | Plynlimon, Powys, Wales |
|  - coordinates | ﻿ / ﻿ |
|  - elevation | 610 m (2,000 ft) |
|  |
| Mouth | Severn Estuary |
|  - location | Bristol Channel, United Kingdom |
|  - elevation | 0 m (0 ft) |
| Length | 354 km (220 mi) |
| Basin size | 11,420 km2 (4,410 sq mi) |
|  |
| Discharge |   |
|  - location | Bewdley, Worcs. SO 7815 7622 |
|  - average | 61.17 m3/s (2,160 cu ft/s) |
|  - maximum | 533.48 m3/s (18,840 cu ft/s)max recorded on 1947-03-21 |
|  |
|  |
| Discharge |   |
|  - location | Apperley, Glos. |
|  - average | 107 m3/s (3,800 cu ft/s) |
|  |
|  |
| Discharge |   |
|  - location | Montford, Shrops. |
|  - average | 43.46 m3/s (1,535 cu ft/s) |
|  |
| Basin features |
| Tributaries |   |
|  - left | Vyrnwy, Tern, Stour, Warwickshire Avon, Bristol Avon |
|  - right | Teme, Leadon, Wye |

The **River Severn** (Welsh: *Afon Hafren*, Latin: *Sabrina*) is the longest river in Great Britain. It is about 354 kilometres (220 miles) long. It starts in the Cambrian Mountains of centre Wales. It then flows through Shropshire, Worcestershire and Gloucestershire. The county towns of Shrewsbury, Worcester, and Gloucester are on its banks. The Severn is the greatest river in terms of water flow in England and Wales.

The river is usually considered to become the Severn Estuary after the Second Severn Crossing. The river then discharges into the Bristol Channel, which discharges into the Atlantic Ocean. The Severn's drainage basin area is 0 k, excluding the River Wye and the Bristol Avon which flow into the Severn Estuary.

## Other websites

 Media related to River Severn at Wikimedia Commons
# Liverpool and Manchester Railway

The **Liverpool and Manchester Railway** was the first inter-city railway in the world. It opened on 15 September 1830 between the Lancashire cities of Liverpool and Manchester. It was also the first railway to only have locomotives driven by steam power, with no horse-drawn traffic permitted at any time; the first to be entirely double track; the first to have a true signalling system; the first to be fully timetabled; and the first to carry mail.

It was designed and built by George Stephenson. It made money, and influenced the development of railways across Britain in the 1830s.
# Standard gauge

The **standard gauge** (also called the **Stephenson gauge** after George Stephenson, or **normal gauge**) is a popular rail gauge. About 60% of the world's current railway lines use this gauge. The distance between the inside edges of the rails of standard gauge track is 1,435 mm (4 ft 8 1⁄2 in).
# Chicago "L"

| Chicago "L" |
| --- |
| A Pink Line train approaching Randolph/Wabash station |
| Overview |
| Locale | Chicago, Illinois, United States |
| Transit type | Rapid transit |
| Number of lines | 8 |
| Line number |   Red Line   Orange Line   Yellow Line   Green Line   Blue Line   Purple Line   Brown Line   Pink Line |
| Number of stations | 145 |
| Daily ridership | 767,730 (average weekday, 2015) |
| Annual ridership | 238.36 million (2016) |
| Chief executive | Dorval R. Carter, Jr. |
| Headquarters | 567 West Lake St. Chicago, Illinois |
| Website | Chicago Transit Authority |
| Operation |
| Began operation | June 6, 1892 |
| Operator(s) | Chicago Transit Authority |
| Technical |
| System length | 102.8 mi (165.4 km) |
| Track gauge | 4 ft 8 1⁄2 in (1,435 mm) standard gauge |
| Minimum radius of curvature | 90 feet (27,432 mm) |
| Electrification | Third rail, 600 V DC |
| Top speed | 55 mph (89 km/h) |
|

| System map |
| --- |
|  |

 |

The **Chicago "L"** (short for "elevated railway") is the Chicago rapid transit system. It serves the city of Chicago and some of its surrounding suburbs in the U.S. state of Illinois.

The "L" is operated by the Chicago Transit Authority (CTA). It is the fourth-largest rapid transit system in the United States. It is 102.8 miles (165.4 km) long, and the second-busiest rail mass transit system in the United States, after the New York City Subway.

Chicago's "L" has 24-hour service on some portions of its network. It is one of only five rapid transit systems in the United States to do so. The oldest sections of the Chicago "L" started operations in 1892, making it the second-oldest rapid transit system in the Americas, after New York City's elevated lines.

## Related pages

* Chicago Loop
# Transport network

A **transport network**, or **transportation network** is a network of roads, railways, streets, pipes, power lines, or any structure that lets either movement of vehicles or flow of some commodity.
# Request stop

A sign of a request stop (*zastávka na znamení*) of urban bus line in Prague
A **request stop** is a stop that buses or trains only stop on request; Buses and trains only stop if there are passengers or freight to be picked up or dropped off.

## Other websites

* Media related to Request stops at Wikimedia Commons
# Fishplate

Fishplate on the Bluebell Railway
In rail terminology, a **fishplate**, **splice bar** or **joint bar** is a metal bar that is bolted to the ends of two rails to join them together in a track. The name is derived from *fish*, a wooden bar with a curved profile used to strengthen a ship's mast. The top and bottom edges are tapered inwards so the device wedges itself between the top and bottom of the rail when it is bolted into place. In rail transport modelling, a fishplate is often a small copper or nickel silver plate that slips onto both rails to provide the functions of maintaining alignment and electrical continuity.