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28,005 | # Semi-Automatic Ground Environment
## Background
### Earlier systems {#earlier_systems}
Just prior to World War II, Royal Air Force (RAF) tests with the new Chain Home (CH) radars had demonstrated that relaying information to the fighter aircraft directly from the radar sites was not feasible. The radars determined... | 461 | Semi-Automatic Ground Environment | 1 |
28,005 | # Semi-Automatic Ground Environment
## Background
### Valley Committee {#valley_committee}
When the Soviet Union tested its first atomic bomb in August 1949, the topic of air defense of the US became important for the first time. A study group, the \"Air Defense Systems Engineering Committee\", was set up under the d... | 701 | Semi-Automatic Ground Environment | 2 |
28,005 | # Semi-Automatic Ground Environment
## Background
### Project Lincoln {#project_lincoln}
Loomis took over direction of Project Lincoln and began planning by following the lead of the earlier RadLab. By September 1951, only months after the Charles report, Project Lincoln had more than 300 employees. By the end of the... | 655 | Semi-Automatic Ground Environment | 3 |
28,005 | # Semi-Automatic Ground Environment
## Development
Systems scientist Jay Forrester was instrumental in directing the development of the key concept of an interception system during his work at Servomechanisms Laboratory of MIT. The concept of the system, according to the Lincoln Laboratory site was to \"develop a dig... | 501 | Semi-Automatic Ground Environment | 4 |
28,005 | # Semi-Automatic Ground Environment
## Deployment
In 1957, SAGE System groundbreaking at McChord AFB was for DC-12 where the \"electronic brain\" began arriving in November 1958, and the \"first SAGE regional battle post \[CC-01\] began operating in Syracuse, New York in early 1959\".`{{r|Schaffel}}`{=mediawiki} BOMA... | 774 | Semi-Automatic Ground Environment | 5 |
28,005 | # Semi-Automatic Ground Environment
## Deployment
### SAGE sites {#sage_sites}
The SAGE system included a direction center (DC) assigned to air defense sectors as they were defined at the time.
+----------+---------+-------+--------------------------------------------------------------------------+------------------... | 1,152 | Semi-Automatic Ground Environment | 6 |
28,005 | # Semi-Automatic Ground Environment
## Description
The environment allowed radar station personnel to monitor the radar data and systems\' status (e.g., Arctic Tower radome pressure) and to use the range height equipment to process height requests from Direction Center (DC) personnel. DCs received the Long Range Rada... | 1,037 | Semi-Automatic Ground Environment | 7 |
28,005 | # Semi-Automatic Ground Environment
## Description
### Interceptors
ADC aircraft such as the F-94 Starfire, F-89 Scorpion, F-101B Voodoo, and F-4 Phantom were controlled by SAGE GCI. The F-104 Starfighter was \"too small to be equipped with \[SAGE\] data link equipment\" and used voice-commanded GCI,`{{r|Schaffel}}`{... | 112 | Semi-Automatic Ground Environment | 8 |
28,005 | # Semi-Automatic Ground Environment
## Improvements
Partially solid-state AN/FST-2B and later AN/FYQ-47 computers replaced`{{When|date=February 2013}}`{=mediawiki} the AN/FST-2,`{{r|FYQ47}}`{=mediawiki} and sectors without AN/FSQ-7 centrals requiring a \"weapon direction control device\" for USAF air defense used the... | 583 | Semi-Automatic Ground Environment | 9 |
28,016 | # Steiner system
250px\|right\|thumbnail\|The Fano plane is a Steiner triple system S(2,3,7). The blocks are the 7 lines, each containing 3 points. Every pair of points belongs to a unique line. In combinatorial mathematics, a **Steiner system** (named after Jakob Steiner) is a type of block design, specifically a t-d... | 766 | Steiner system | 0 |
28,016 | # Steiner system
## Types of Steiner systems {#types_of_steiner_systems}
### Resolvable Steiner systems {#resolvable_steiner_systems}
Some of the S(2,3,n) systems can have their triples partitioned into (n-1)/2 sets each having (n/3) pairwise disjoint triples. This is called *resolvable* and such systems are called *... | 361 | Steiner system | 1 |
28,016 | # Steiner system
## Properties
It is clear from the definition of `{{math|S(''t'', ''k'', ''n'')}}`{=mediawiki} that $1 < t < k < n$. (Equalities, while technically possible, lead to trivial systems.)
If `{{math|S(''t'', ''k'', ''n'')}}`{=mediawiki} exists, then taking all blocks containing a specific element and di... | 371 | Steiner system | 2 |
28,016 | # Steiner system
## History
Steiner triple systems were defined for the first time by Wesley S. B. Woolhouse in 1844 in the Prize question #1733 of Lady\'s and Gentlemen\'s Diary. The posed problem was solved by `{{Harvs|first=Thomas|last=Kirkman|authorlink=Thomas Kirkman|year=1847|txt}}`{=mediawiki}. In 1850 Kirkman... | 781 | Steiner system | 3 |
28,016 | # Steiner system
## The Steiner system S(5, 8, 24) {#the_steiner_system_s5_8_24}
The Steiner system S(5, 8, 24), also known as the **Witt design** or **Witt geometry**, was first described by `{{Harvs|txt|authorlink=Robert Daniel Carmichael|last=Carmichael|year=1931}}`{=mediawiki} and rediscovered by `{{Harvs|txt|las... | 860 | Steiner system | 4 |
28,024 | # Sontaran
The **Sontarans** (`{{IPAc-en|s|ɒ|n|'|t|ɑːr|ən}}`{=mediawiki} `{{respell|son|TAR|ən}}`{=mediawiki}) are a fictional race of extraterrestrial humanoids principally portrayed in the British science fiction television programme *Doctor Who* and its spin-off series *The Sarah Jane Adventures*. A warrior race ch... | 832 | Sontaran | 0 |
28,024 | # Sontaran
## Characteristics
### Reproduction and gender identity {#reproduction_and_gender_identity}
The Sontarans are a monogender-asexual (a \"male gender-only\" species); they reproduce by means of cloning rather than sexual reproduction, and thus for the most part are extremely similar in appearance. Human char... | 493 | Sontaran | 1 |
28,024 | # Sontaran
## Characteristics
### Technology
The Tenth Sontaran Battle Fleet in the new series consists of a Command Ship and a number of capsules that can be moved into position when Battle Status is enjoined. Sontaran ships are impervious to nuclear missiles, however in War of the Sontarans they are vulnerable to b... | 713 | Sontaran | 2 |
28,024 | # Sontaran
## Appearances
### Television
During rehearsals for their first appearance, Kevin Lindsay, who portrayed the original Sontaran, Linx, pronounced the race\'s name as \"*son-TAR-an*.\" Alan Bromly, the director, tried to correct him by saying it should be pronounced with the stress on the first syllable. Li... | 933 | Sontaran | 3 |
28,024 | # Sontaran
## Appearances
### Other appearances {#other_appearances}
Big Finish Productions first used the Sontarans for their audio drama *Heroes of Sontar*, a 2011 Fifth Doctor (Peter Davison) story, depicting the Doctor and his companions being forced to aid a Sontaran attack squad against a dangerous enemy that h... | 1,153 | Sontaran | 4 |
28,024 | # Sontaran
## Appearances
### Summary of appearances {#summary_of_appearances}
This list does not include Strax who has his own list | 20 | Sontaran | 5 |
28,028 | # Speed skating
**Speed skating** is a competitive form of ice skating in which the competitors race each other in travelling a certain distance on skates. Types of speed skating are long-track speed skating, short-track speed skating, and marathon speed skating. In the Olympic Games, long-track speed skating is usual... | 669 | Speed skating | 0 |
28,028 | # Speed skating
## History
The origins of speed skating date back over a millennium in the North of Europe, especially Scandinavia and the Netherlands, where the natives added bones to their shoes and used them to travel on frozen rivers, canals and lakes. Later, in Norway, King Eystein Magnusson, later King Eystein ... | 817 | Speed skating | 1 |
28,028 | # Speed skating
## History
### Olympic Games {#olympic_games}
*Main article: Speed skating at the Winter Olympics* At the 1914 Olympic Congress, the delegates agreed to include ice speed skating in the 1916 Olympics, after figure skating had featured in the 1908 Olympics. However, World War I put an end to the plans ... | 390 | Speed skating | 2 |
28,028 | # Speed skating
## History
### Technical developments {#technical_developments}
Artificial ices entered the long track competitions with the 1960 Winter Olympics, and the competitions in 1956 on Lake Misurina were the last Olympic competitions on natural ice. 1960 also saw the first Winter Olympic competitions for wo... | 609 | Speed skating | 3 |
28,028 | # Speed skating
## Rules
### Short track {#short_track}
Races are run counter-clockwise on a 111-meter track. Short track races are almost always run in a mass start format in which two to six skaters may race at once. Skaters may be disqualified for false starts, impeding, and cutting inside the track. False starts... | 595 | Speed skating | 4 |
28,028 | # Speed skating
## Equipment
**Speed skates** Speed skates differ greatly from hockey skates and figure skates. Unlike hockey skates and figure skates, speed skates cut off at the ankle and are built more like a shoe than a boot to allow for more ankle compression. The blades range in length from 30 to 45 cm dependin... | 392 | Speed skating | 5 |
28,046 | # Closings and cancellations following the September 11 attacks
Many closings and cancellations followed the September 11 attacks, including major landmarks, buildings, restrictions on access to Lower Manhattan, as well as postponement or cancellation of major sporting and other events. Landmarks were closed primarily... | 386 | Closings and cancellations following the September 11 attacks | 0 |
28,046 | # Closings and cancellations following the September 11 attacks
## Lower Manhattan {#lower_manhattan}
### Mass transit {#mass_transit}
#### New York City Subway {#new_york_city_subway}
The tracks and stations under the World Trade Center were shut down within minutes of the first plane crash. All remaining New York ... | 1,092 | Closings and cancellations following the September 11 attacks | 1 |
28,046 | # Closings and cancellations following the September 11 attacks
## North American airspace {#north_american_airspace}
The entire airspaces of the United States and Canada were closed (\"ground stop\") by order of FAA National Operations Manager Ben Sliney (who was working his first day in that position) except for mi... | 460 | Closings and cancellations following the September 11 attacks | 2 |
28,046 | # Closings and cancellations following the September 11 attacks
## Precautionary building closings and evacuations {#precautionary_building_closings_and_evacuations}
Many businesses across the United States closed after the intentional nature of the events became clear, and many national landmarks and financial distr... | 700 | Closings and cancellations following the September 11 attacks | 3 |
28,051 | # Airport security repercussions due to the September 11 attacks
After the September 11 attacks, there was an immediate call to action regarding the state of aviation security measures as the hijackers involved in 9/11 were able to successfully pass through security and take command of the plane. The existing security... | 1,148 | Airport security repercussions due to the September 11 attacks | 0 |
28,064 | # Financial assistance following the September 11 attacks
Charities and relief agencies raised over \$657 million in the three weeks following the September 11, 2001 attacks, the vast bulk going to immediate survivors and victims\' families.
## Government assistance {#government_assistance}
On September 21, 2001, th... | 545 | Financial assistance following the September 11 attacks | 0 |
28,070 | # Communication during the September 11 attacks
Communication problems and successes played an important role during the September 11 attacks in 2001 and their aftermath. Systems were variously destroyed or overwhelmed by loads greater than they were designed to carry, or failed to operate as intended or desired.
## ... | 600 | Communication during the September 11 attacks | 0 |
28,070 | # Communication during the September 11 attacks
## Victims
Cell phones and in-plane credit card phones played a major role during and after the attack, starting with hijacked passengers who called family or notified the authorities about what was happening. Passengers and crew who made calls include: Sandra Bradshaw,... | 393 | Communication during the September 11 attacks | 1 |
28,070 | # Communication during the September 11 attacks
## General public {#general_public}
After the attack, the cell phone networks of New York City and the Tri-State area were rapidly overloaded (a mass call event) as traffic doubled over normal levels. Cell phone traffic also overloaded across the East Coast, leading to ... | 441 | Communication during the September 11 attacks | 2 |
28,070 | # Communication during the September 11 attacks
## Radio communications {#radio_communications}
**Radio communications during the September 11 attacks** served a vital role in coordinating rescue efforts by New York Police Department, New York Fire Department, Port Authority Police Department, and emergency medical s... | 801 | Communication during the September 11 attacks | 3 |
28,070 | # Communication during the September 11 attacks
## Radio communications {#radio_communications}
### Voice radio systems {#voice_radio_systems}
NIST calculated that about one third of radio messages transmitted during the surge of communications were incomplete or unintelligible. Documentary footage suggests the tacti... | 1,200 | Communication during the September 11 attacks | 4 |
28,070 | # Communication during the September 11 attacks
## Radio communications {#radio_communications}
### Voice radio systems {#voice_radio_systems}
#### Fire and EMS dispatch channels {#fire_and_ems_dispatch_channels}
##### Port Authority fire repeater system (Repeater 7) {#port_authority_fire_repeater_system_repeater_7}
... | 1,203 | Communication during the September 11 attacks | 5 |
28,070 | # Communication during the September 11 attacks
## Radio communications {#radio_communications}
### Voice radio systems {#voice_radio_systems}
#### Fire and EMS dispatch channels {#fire_and_ems_dispatch_channels}
##### Port Authority fire repeater system (Repeater 7) {#port_authority_fire_repeater_system_repeater_7}
... | 259 | Communication during the September 11 attacks | 6 |
28,070 | # Communication during the September 11 attacks
## Radio communications {#radio_communications}
### Voice radio systems {#voice_radio_systems}
#### Interoperability
The federal *9/11 Commission Report* included recommendations on communications systems used by police, fire, and emergency medical services (EMS) at the... | 1,441 | Communication during the September 11 attacks | 7 |
28,070 | # Communication during the September 11 attacks
## Radio communications {#radio_communications}
### Mobile data terminals {#mobile_data_terminals}
All 911 ambulances and other FDNY vehicles have data terminals, sometimes referred to by staff in recordings and transcripts as MDTs. These terminals are connected to the ... | 554 | Communication during the September 11 attacks | 8 |
28,113 | # Timeline for September following the September 11 attacks
The September 11 attacks of 2001 were a major event that had a significant long-lasting impact even beyond the day of the attacks itself. This article summarizes events which relate to the attacks in the remaining days of September 2001. News coverage was sig... | 614 | Timeline for September following the September 11 attacks | 0 |
28,113 | # Timeline for September following the September 11 attacks
## September 2001 {#september_2001}
### Thursday, September 13 {#thursday_september_13}
- Some commercial flights resume, and several airports are reopened, but under strict security protocols from the FAA.
- Before **1:00 a.m.**: German police raid an a... | 495 | Timeline for September following the September 11 attacks | 1 |
28,113 | # Timeline for September following the September 11 attacks
## September 2001 {#september_2001}
### Friday, September 14 {#friday_september_14}
The National Day of Prayer and Remembrance
- Church and memorial services are held throughout the world. These include a special service held in London, which was attended... | 555 | Timeline for September following the September 11 attacks | 2 |
28,113 | # Timeline for September following the September 11 attacks
## September 2001 {#september_2001}
### Saturday, September 15 {#saturday_september_15}
- The Department of Defense releases a casualty update: Aerographer\'s Mate First Class Edward Thomas Earhart, 26, Salt Lick, Kentucky, is confirmed dead. Herbert W. Ho... | 701 | Timeline for September following the September 11 attacks | 3 |
28,113 | # Timeline for September following the September 11 attacks
## September 2001 {#september_2001}
### Monday, September 17 {#monday_september_17}
- The U.S. demands that Pakistan close its borders to Afghan refugees. Pakistan immediately complies.
- Major League Baseball games recommence kicked off by Jack Buck\'s ... | 984 | Timeline for September following the September 11 attacks | 4 |
28,113 | # Timeline for September following the September 11 attacks
## September 2001 {#september_2001}
### Thursday, September 20 {#thursday_september_20}
- Stock markets continue dramatic slide.
- Pakistani general/President Pervez Musharraf gives a speech asking the country to go along with government decision to supp... | 909 | Timeline for September following the September 11 attacks | 5 |
28,113 | # Timeline for September following the September 11 attacks
## September 2001 {#september_2001}
### Week of Monday, September 24 {#week_of_monday_september_24}
- U.S. stock markets rebound somewhat.
- Over 100,000 tons of debris have been removed from the World Trade Center site. It is clear that no remains will ... | 891 | Timeline for September following the September 11 attacks | 6 |
28,113 | # Timeline for September following the September 11 attacks
## September 2001 {#september_2001}
### Sunday, September 30 {#sunday_september_30}
- The official count of bodies found at the site of the World Trade Center is 314; 255 have been identified. The official missing count at the World Trade Center is 5,657.
... | 170 | Timeline for September following the September 11 attacks | 7 |
28,132 | # Sidehill gouger
In American folklore, a **Sidehill gouger** is a fearsome critter adapted to living on hillsides by having legs on one side of their body shorter than the legs on the opposite side, having evolved to resemble any form of mammals such as pangolins, goats, humans, and bears. This peculiarity allows the... | 503 | Sidehill gouger | 0 |
28,145 | # September 15
| 3 | September 15 | 0 |
28,150 | # Sculptor Group
The **Sculptor Group** is a loose group of galaxies visible near the south galactic pole. The group is one of the closest groups of galaxies to the Local Group; the distance to the center of the group from the Milky Way is approximately 3.9 Mpc.
The Sculptor Galaxy (NGC 253) and a few other galaxies ... | 554 | Sculptor Group | 0 |
28,156 | # Salem al-Hazmi
**Salem Muhammed al-Hazmi** (*translit=Sālam al-Ḥāzmī*; February 2, 1981`{{Snd}}`{=mediawiki} September 11, 2001) was a Saudi terrorist hijacker who was one of the five hijackers who assisted in the hijacking of American Airlines Flight 77 as part of the September 11 attacks. The aircraft was delibera... | 893 | Salem al-Hazmi | 0 |
28,156 | # Salem al-Hazmi
## In popular culture {#in_popular_culture}
- Yemeni-Canadian actor Sam Al Esai portrayed Salem al-Hazmi in the Canadian TV series *Mayday* Season 16: Episode 2 (2016) called \"9/11: The Pentagon Attack\" and *Air Crash Investigation Special Report* Season 2: Episode 1 (2019) called \"Headline News... | 47 | Salem al-Hazmi | 1 |
28,157 | # Satsuma Province
Satsuma kuni no miyatsuko \|flag_p1 = \|s1 = Kagoshima Prefecture \|flag_s1 = \|title_leader = \|leader1 = \|year_leader1 = \|leader2 = \|year_leader2 = \|capital = Satsuma District \|coordinates = \|political_subdiv = \|today = Kagoshima Prefecture \|year_start = 702 \|year_end = 1871 \|event_start... | 326 | Satsuma Province | 0 |
28,164 | # Simon Ockley
**Simon Ockley** (1678`{{snd}}`{=mediawiki}9 August 1720) was a British Orientalist.
## Biography
Ockley was born at Exeter. He was educated at Queens\' College, Cambridge, and graduated B.A. in 1697, MA. in 1701, and B.D. in 1710. He became a fellow of Jesus College and vicar of Swavesey, and in 1711... | 358 | Simon Ockley | 0 |
28,170 | # Son of God
*Son of God* (film)\|other uses\|Son of God (disambiguation)}} `{{Distinguish|Demigod|Son of Heaven}}`{=mediawiki}
Historically, many rulers have assumed titles such as the **son of God**, the **son of a god** or the **son of heaven**.
The term \"Son of God\" is used in the Hebrew Bible as another way t... | 312 | Son of God | 0 |
28,170 | # Son of God
## Rulers and imperial titles {#rulers_and_imperial_titles}
Throughout history, emperors and rulers ranging from the Western Zhou dynasty (c. 1000 BC) in China to Alexander the Great (c. 360 BC) to the Emperor of Japan (c. 600 AD) have assumed titles that reflect a filial relationship with deities.
T... | 1,102 | Son of God | 1 |
28,170 | # Son of God
## Christianity
In Christianity, the title \"Son of God\" refers to the status of Jesus as the divine son of God the Father. It derives from several uses in the New Testament and early Christian theology. The term is used in all four gospels, the Acts of the Apostles, and the Pauline and Johannine litera... | 269 | Son of God | 2 |
28,170 | # Son of God
## `{{Anchor|Judaism}}`{=mediawiki}Judaism
Further information: Sons of God, Son of God (Christianity)#Old Testament usage Although references to \"sons of God\", \"son of God\" and \"son of the `{{Lord}}`{=mediawiki}\" are occasionally found in Jewish literature, they never refer to physical descent fro... | 521 | Son of God | 3 |
28,174 | # Data storage
`{{Memory types}}`{=mediawiki}
**Data storage** is the recording (storing) of information (data) in a **storage medium**. Handwriting, phonographic recording, magnetic tape, and optical discs are all examples of storage media. Biological molecules such as RNA and DNA are considered by some as data stor... | 563 | Data storage | 0 |
28,177 | # Simony
**Simony** (`{{IPAc-en|ˈ|s|ɪ|m|ə|n|i}}`{=mediawiki}) is the act of selling church offices and roles or sacred things. It is named after Simon Magus, who is described in the Acts of the Apostles as having offered two disciples of Jesus payment in exchange for their empowering him to impart the power of the Hol... | 569 | Simony | 0 |
28,177 | # Simony
## Church of England {#church_of_england}
The Church of England struggled with the practice after its separation from Rome. For the purposes of English law, simony is defined by William Blackstone as \"obtain\[ing\] orders, or a licence to preach, by money or corrupt practices\" or, more narrowly, \"the corr... | 360 | Simony | 1 |
28,178 | # September 26
| 3 | September 26 | 0 |
28,186 | # Symmetry group
In group theory, the **symmetry group** of a geometric object is the group of all transformations under which the object is invariant, endowed with the group operation of composition. Such a transformation is an invertible mapping of the ambient space which takes the object to itself, and which preser... | 843 | Symmetry group | 0 |
28,186 | # Symmetry group
## Two dimensions {#two_dimensions}
Up to conjugacy the discrete point groups in two-dimensional space are the following classes:
- cyclic groups C~1~, C~2~, C~3~, C~4~, \... where C~*n*~ consists of all rotations about a fixed point by multiples of the angle 360°/*n*
- dihedral groups D~1~, D~2... | 878 | Symmetry group | 1 |
28,186 | # Symmetry group
## Group structure in terms of symmetries {#group_structure_in_terms_of_symmetries}
Cayley\'s theorem states that any abstract group is a subgroup of the permutations of some set *X*, and so can be considered as the symmetry group of *X* with some extra structure. In addition, many abstract features ... | 375 | Symmetry group | 2 |
28,211 | # Stan Kelly-Bootle
**Stanley Bootle**, known as **Stan Kelly-Bootle** (15 September 1929 -- 16 April 2014), was a British author, academic, singer-songwriter and computer scientist.
He took his stage name **Stan Kelly** (he was not known as Stan Kelly-Bootle in folk music circles) from the Irish folk song \"Kelly, t... | 585 | Stan Kelly-Bootle | 0 |
28,211 | # Stan Kelly-Bootle
## Writing career {#writing_career}
In 1973, Kelly-Bootle left Sperry-UNIVAC and became a freelance consultant, writer and programmer. He was known in the computer community for *The Devil\'s DP Dictionary* and its second edition, *The Computer Contradictionary* (1995 ), which he authored. These w... | 280 | Stan Kelly-Bootle | 1 |
28,212 | # Skewness
In probability theory and statistics, **skewness** is a measure of the asymmetry of the probability distribution of a real-valued random variable about its mean. The skewness value can be positive, zero, negative, or undefined.
For a unimodal distribution (a distribution with a single peak), negative skew ... | 562 | Skewness | 0 |
28,212 | # Skewness
## Relationship of mean and median {#relationship_of_mean_and_median}
The skewness is not directly related to the relationship between the mean and median: a distribution with negative skew can have its mean greater than or less than the median, and likewise for positive skew. In the older notion of nonpar... | 388 | Skewness | 1 |
28,212 | # Skewness
## Definition
### Fisher\'s moment coefficient of skewness {#fishers_moment_coefficient_of_skewness}
The skewness $\gamma_1$ of a random variable `{{mvar|X}}`{=mediawiki} is the third standardized moment $\tilde{\mu}_3$, defined as:
$\gamma_1 := \tilde{\mu}_3 = \operatorname{E}\left[\left(\frac{X-\mu}{\s... | 868 | Skewness | 2 |
28,212 | # Skewness
## Other measures of skewness {#other_measures_of_skewness}
thumb\|upright=1.35\|Comparison of mean, median and mode of two log-normal distributions with the same medians and different skewnesses.
Other measures of skewness have been used, including simpler calculations suggested by Karl Pearson (not to b... | 754 | Skewness | 3 |
28,219 | # Spontaneous emission
**Spontaneous emission** is the process in which a quantum mechanical system (such as a molecule, an atom or a subatomic particle) transits from an excited energy state to a lower energy state (e.g., its ground state) and emits a quantized amount of energy in the form of a photon. Spontaneous em... | 380 | Spontaneous emission | 0 |
28,219 | # Spontaneous emission
## Introduction
If a light source (\'the atom\') is in an excited state with energy $E_2$, it may spontaneously decay to a lower lying level (e.g., the ground state) with energy $E_1$, releasing the difference in energy between the two states as a photon. The photon will have angular frequency ... | 287 | Spontaneous emission | 1 |
28,219 | # Spontaneous emission
## Theory
Spontaneous transitions were not explainable within the framework of the Schrödinger equation, in which the electronic energy levels were quantized, but the electromagnetic field was not. Given that the eigenstates of an atom are properly diagonalized, the overlap of the wavefunctions... | 683 | Spontaneous emission | 2 |
28,219 | # Spontaneous emission
## Rate of spontaneous emission {#rate_of_spontaneous_emission}
The rate of spontaneous emission (i.e., the radiative rate) can be described by Fermi\'s golden rule. The rate of emission depends on two factors: an \'atomic part\', which describes the internal structure of the light source and a... | 266 | Spontaneous emission | 3 |
28,219 | # Spontaneous emission
## Radiative and nonradiative decay: the quantum efficiency {#radiative_and_nonradiative_decay_the_quantum_efficiency}
In the rate-equation above, it is assumed that decay of the number of excited states $N$ only occurs under emission of light. In this case one speaks of full radiative decay an... | 389 | Spontaneous emission | 4 |
28,230 | # Speaker for the Dead
*Speaker of the Dead*}} `{{Infobox book | <!-- See Wikipedia:WikiProject_Novels or Wikipedia:WikiProject_Books -->
| name = Speaker for the Dead
| title_orig =
| translator =
| image = Speaker dead cover.jpg
| caption = Cover of first edition (hardcover)
| author = [[Ors... | 660 | Speaker for the Dead | 0 |
28,230 | # Speaker for the Dead
## Synopsis
Eight years after the Descolada virus has been brought under control, Xenologer Pipo and his thirteen-year-old son and apprentice Libo have developed a friendship with the Pequeninos. They allow Novinha to join their science team as the colony\'s only xenobiologist after she passes ... | 909 | Speaker for the Dead | 1 |
28,230 | # Speaker for the Dead
## Film adaptation {#film_adaptation}
At the Los Angeles Times Book Festival on April 20, 2013, Card stated that he did not want *Speaker for the Dead* to be made into a film: \"*Speaker for the Dead* is unfilmable,\" Card said in response to a question from the audience. \"It consists of talki... | 248 | Speaker for the Dead | 2 |
28,232 | # Star catalogue
A **star catalogue** is an astronomical catalogue that lists stars. In astronomy, many stars are referred to simply by catalogue numbers. There are a great many different star catalogues which have been produced for different purposes over the years, and this article covers only some of the more frequ... | 1,106 | Star catalogue | 0 |
28,232 | # Star catalogue
## Historical catalogues {#historical_catalogues}
### Pre-Columbian Americas {#pre_columbian_americas}
The *Motul Dictionary*, compiled in the 16th century by an anonymous author (although attributed to Fray Antonio de Ciudad Real), contains a list of stars originally observed by the ancient Mayas. T... | 266 | Star catalogue | 1 |
28,232 | # Star catalogue
## Full-sky catalogues (in chronological order) {#full_sky_catalogues_in_chronological_order}
Bayer and Flamsteed covered only a few thousand stars between them. In theory, full-sky catalogues try to list every star in the sky. There are, however, billions of stars resolvable by 21st century telescop... | 839 | Star catalogue | 2 |
28,232 | # Star catalogue
## Full-sky catalogues (in chronological order) {#full_sky_catalogues_in_chronological_order}
### SAO
The Smithsonian Astrophysical Observatory catalogue was compiled in 1966 from various previous astrometric catalogues, and contains only the stars to about ninth magnitude for which accurate proper m... | 865 | Star catalogue | 3 |
28,232 | # Star catalogue
## Specialized catalogues {#specialized_catalogues}
Specialized catalogues make no effort to list all the stars in the sky, working instead to highlight a particular type of star, such as variables or nearby stars.
### ADS
Aitken\'s double star catalogue (1932) lists 17,180 double stars north of de... | 568 | Star catalogue | 4 |
28,232 | # Star catalogue
## Specialized catalogues {#specialized_catalogues}
### Proper motion catalogues {#proper_motion_catalogues}
A common way of detecting nearby stars is to look for relatively high proper motions. Several catalogues exist, of which we\'ll mention a few. The Ross and Wolf catalogues pioneered the domain... | 644 | Star catalogue | 5 |
28,233 | # Stellar designations and names
right\|thumb\|upright=1.7\|The trend toward ever more catalogued objects in the Universe In astronomy, stars have a variety of different **stellar designations and names**, including catalogue designations, current and historical proper names, and foreign language names.
Only a tiny m... | 327 | Stellar designations and names | 0 |
28,233 | # Stellar designations and names
## Proper names {#proper_names}
Several hundred of the brightest stars had traditional names, most of which derived from Arabic, but a few from Latin. There were a number of problems with these names, however:
- Spellings were often not standardized (Almach or Almaach or Almak or A... | 739 | Stellar designations and names | 1 |
28,233 | # Stellar designations and names
## Catalogue designations {#catalogue_designations}
In the absence of any better means of designating a star, catalogue designations are generally used. Many star catalogues are used for this purpose; see star catalogues.
### By constellation {#by_constellation}
The first modern sch... | 609 | Stellar designations and names | 2 |
28,233 | # Stellar designations and names
## Sale of star names by non-scientific entities {#sale_of_star_names_by_non_scientific_entities}
Star naming rights are not available for sale via the IAU or any other scientific body. Rather, star names are selected on a non-commercial basis by a small number of international organi... | 203 | Stellar designations and names | 3 |
28,237 | # Space Shuttle Columbia
**Space Shuttle *Columbia*** (**OV-102**) was a Space Shuttle orbiter manufactured by Rockwell International and operated by NASA. Named after the first American ship to circumnavigate the globe, and the female personification of the United States, *Columbia* was the first of five Space Shuttl... | 619 | Space Shuttle Columbia | 0 |
28,237 | # Space Shuttle Columbia
## History
Construction began on *Columbia* in 1975 at Rockwell International\'s (formerly North American Aviation/North American Rockwell) principal assembly facility in Palmdale, California, a suburb of Los Angeles. *Columbia* was named after the American sloop *Columbia Rediviva* which, fr... | 980 | Space Shuttle Columbia | 1 |
28,237 | # Space Shuttle Columbia
## First operational orbiter {#first_operational_orbiter}
### Weight
As the second orbiter to be constructed and the first able to fly into space, *Columbia* was roughly 8000 lb heavier than subsequent orbiters such as *Endeavour* when she was first constructed, which had benefited from adva... | 963 | Space Shuttle Columbia | 2 |
28,237 | # Space Shuttle Columbia
## First operational orbiter {#first_operational_orbiter}
### OEX/MADS \"black box\" {#oexmads_black_box}
One unique feature that permanently stayed on *Columbia* from STS-1 to STS-107 was the OEX (Orbiter Experiments) box or MADS (Modular Auxiliary Data System) recorder. On March 19, 2003, t... | 349 | Space Shuttle Columbia | 3 |
28,237 | # Space Shuttle Columbia
## Flights
*Columbia* flew 28 missions, gathering 300.74 days spent in space with 4,808 orbits and a total distance of 125204911.5 mi until STS-107.
Though having been in service during the Shuttle-Mir and International Space Station programs, *Columbia* did not fly any missions that visited... | 793 | Space Shuttle Columbia | 4 |
28,237 | # Space Shuttle Columbia
## Final mission and destruction {#final_mission_and_destruction}
*Columbia* disintegrated on February 1, 2003, around 09:00 EST during atmospheric re-entry after a 16-day scientific mission. The Columbia Accident Investigation Board has determined that one of *Columbia\'s* wings, made of a c... | 312 | Space Shuttle Columbia | 5 |
28,237 | # Space Shuttle Columbia
## Tributes and memorials {#tributes_and_memorials}
### Patricia Huffman Smith Museum {#patricia_huffman_smith_museum}
The debris field encompassed hundreds of miles across Texas extending into Louisiana and Arkansas. The nose cap and remains of all seven crew members were found in Sabine Co... | 455 | Space Shuttle Columbia | 6 |
28,237 | # Space Shuttle Columbia
## In popular culture {#in_popular_culture}
A refurbished *Columbia* features prominently in a 1999 episode of *Cowboy Bebop*, being used to rescue series protagonist Spike from burning up in Earth\'s atmosphere after his ship runs out of fuel. *Columbia* is depicted taking off horizontally w... | 415 | Space Shuttle Columbia | 7 |
28,244 | # Star network
Starnet}} `{{Redirect|Hub and spokes architecture|the network of alliances in the Asia-Pacific region|San Francisco System}}`{=mediawiki} `{{Use American English|date=January 2020}}`{=mediawiki}
A **star network** is an implementation of a spoke--hub distribution paradigm in computer networks. In a sta... | 354 | Star network | 0 |
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