document_title: The Rosie Project

question_text: the rosie project who is her biological father

text: The Rosie Project

text: Synopsis[edit]

text: Don Tillman is an Australian genetics professor who has spent his days organizing his life with the expectation that it will reduce inefficiency, improve himself as a person, and make him an all around happier person. He does not fit in well with others, which has kept Don from dating and having a satisfying romantic life - something that confounds him, as he believes that his IQ, physical health, finances, and social status should otherwise make him an appealing mate. After spending time with his best friend and womanizing colleague Gene and his wife Claudia, Don comes up with the idea of the Wife Project, a questionnaire that would help find the perfect mate. This turns out to be something more easily done in theory, as his questionnaire fails to produce a satisfactory woman and alienates many potential candidates.

text: Soon after Gene introduces him to Rosie, a bartender whom he quickly eliminates as unsuitable per his criteria. Despite this, Don finds himself quickly drawn to her and even goes so far to agree to help her find her biological father, a man that her mother slept with after a graduation party - a task Don terms the "Father Project". Her mother is dead and as such, Rosie cannot ask her for the answer and can only go on the information that her father was an attendee at the party. The two manage to eliminate most of the attendees via DNA testing, which Don secretly does in the university laboratory under the guise of it being an official project. As time progresses Rosie begins to challenge more and more of Don's habits and assumptions, and he's surprised when she reveals that she's working as a bartender in order to pay her way through university while she works on her doctorate in psychology. He also finds that part of the reason that Rosie is so desperate to find her biological father is because of her unsatisfactory relationship with her stepfather Phil. Don also finally meets a woman who fulfills all of his criteria, but he discovers that he is completely unattracted to her.

text: Eventually, the Father Project eliminates all but a select few people, two of which require that Don and Rosie travel to New York City. Once there Rosie forces Don to abandon his schedules in exchange for a spontaneous trip through the city, which he finds that he truly enjoys. This culminates in the two almost having sex, only for Rosie to change her mind because she's unsure that a relationship with Don could actually work out. The two return to Australia where Don continues the Father Project and realizes that his friend Gene may actually be Rosie's father since he also attended the party and is also very promiscuous. After some thinking Don decides that he will test Gene and that he will also try to convince Rosie to marry him, as he has discovered that he is genuinely attracted to her. Despite trying to change to fit what he believes she needs, Don is rejected by Rosie when he says that he does not feel love like others do. However this rejection causes Don to realize that he actually does love Rosie. He also decides to confront her father Phil over her father issues, as Rosie felt neglected because she believed that Phil prioritized his career over her and failed to fulfill a promise to go to Disneyland, a move that she views as representative of their relationship as a whole. Rosie inevitably discovers that Gene may be her real father and she confronts him over this with his wife Claudia, who was largely unaware of his womanizing. Don arrives at the scene just in time to watch Phil punch Gene, after which point Don and Rosie reconcile and she agrees to marry him. She also reconciles with her father and after she marries Don, the two of them move to America to start anew. The book ends with Don running a final test on a sample of Phil's DNA, which confirms that he was her biological father all along, and the whole issue was raised by Rosie's mother because of Gene's negligence in explaining his students the rules of eye color inheritance.

text: Film adaptation[edit]

text: In September 2014 it was confirmed that Sony Pictures optioned film rights to The Rosie Project.[3] Simsion penned the first draft of the script and screenwriters Scott Neustadter and Michael H. Weber were later brought on to work on the final script, with Phil Lord and Christopher Miller set to potentially direct.[3] Jennifer Lawrence was cast as the female lead for the film in July 2015.[4] In October 2015, Lawrence dropped out to star in the film mother! by Darren Aronofsky, director of the Oscar-winning movie Black Swan.[5] In July 2015, Richard Linklater was in talks to direct after Lord and Miller dropped out to do other projects.[6] However, after Lawrence dropped out of the film, so did Linklater.[7] In 2017, Tristar Pictures announced that Ben Taylor would direct the film.[8]

text: Reception[edit]

text: Critical reception for The Rosie Project has been mostly positive and the book was a bestseller in multiple countries.[9][10] NPR gave a favorable review for the work, which they felt was charming.[11] Bill Gates included The Rosie Project as the only novel in his Six Books I’d Recommend.[12]

text: Awards[edit]

text:
International IMPAC Dublin Literary Award, Ireland, Longlisted, 2015[1]
Australian Book Industry's Book of the Year, Winner, 2014[13]
Australian Book Industry's General Fiction Book of the Year, Winner, 2014[14]
Nielsen BookData Booksellers Choice Award, Shortlisted, 2014[1]
Best Debut Fiction, Independent Booksellers of Australia Awards, Shorlisted, 2014[1]
Waverton Good Read Award, United Kingdom, Shortlisted, 2014[1]
The Indie Awards, Shortlisted, 2014[1]
Victorian Premier's Award for Best Unpublished Manuscript, Winner, 2012[15]


document_title: 1958 Pakistani coup d'état

question_text: who was the prime minister of pakistan when martial law was imposed in 1958

root

text: 1958 Pakistani coup d'état

text: History[edit]

text: In 1956, the Constituent Assembly of Pakistan approved a constitution that ended Pakistan's status of an independent Dominion of the British Empire, to create the Islamic Republic of Pakistan. Maj. Gen. Iskander Mirza, the last Governor General of Pakistan, simultaneously became the state's first president. However, the new constitution was followed by political turmoil in Pakistan, which saw a succession of four prime ministers - Chaudhry Muhammad Ali, Huseyn Shaheed Suhrawardy, Ibrahim Ismail Chundrigar and Sir Feroz Khan Noon - in a period of two years.[3] There was already a precedent in Governor General Malik Ghulam Muhammad dismissing prime ministers and ruling by decree, and many viewed Mirza as manipulating the constitution and instigating ousters of governments.[3] The One Unit scheme amalgamating the provinces of Pakistan into two wings - West Pakistan and East Pakistan - was politically controversial and proving difficult to administer. The quick succession of prime ministers fostered the view within the military and in the public that Pakistani politicians were too weak and corrupt to govern effectively, and that the parliamentary system was flawed.

tag: p

text: Martial law[edit]

text: On October 7, President Mirza declared martial law in Pakistan. He abrogated the constitution of 1956, describing it as "unworkable" and full of "dangerous compromises."[4] He dismissed the government of Sir Feroz Khan Noon, dissolved the National Assembly of Pakistan and the provincial legislatures. Mirza also proceeded to outlaw all political parties.[4] He appointed General Ayub Khan, the Commander-in-Chief of the Pakistani army as the Chief Martial Law Administrator and nominated him to become the new Prime Minister of Pakistan, charged with administering the country.[4]

text: Deposing of Mirza[edit]

text: On October 27, Iskander Mirza resigned from the presidency, transferring it to Ayub Khan.[4] Both men saw the other as a rival to their respective positions. Mirza believed his own position had become largely redundant after Ayub Khan assumed most executive powers as chief martial law administrator and prime minister, and acted to assert himself, while Ayub Khan thought Mirza was conspiring against him.[4][5] It is widely held that Ayub Khan and generals loyal to him forced Mirza to resign.[4][5] Mirza was later taken to Quetta, the capital of the province of Baluchistan, before being exiled on November 27 to London, England, where he resided until his death in 1969.[5]

text: Consolidation[edit]

text: Ayub Khan combined the offices of president and prime minister, becoming both the head of state and government. He created a cabinet of technocrats, diplomats and military officers. These included Air Marshal Asghar Khan and Zulfikar Ali Bhutto, the future prime minister. In contrast with future Pakistani military rulers such as Gen. Zia-ul-Haq and Gen. Pervez Musharraf, Ayub Khan did not seek to hold the posts of president and army chief simultaneously.[5] He appointed Gen. Muhammad Musa as the new commander-in-chief.[5] Ayub Khan also obtained judicial validation of his move when the Supreme Court of Pakistan validated and legalised his take-over under the "Doctrine of necessity."[5][6][7]

text: Reactions[edit]

text: The coup was received positively in Pakistan as a relief from unstable governments and weak political leadership.[5] There was hope that a strong central leadership could stabilise the economy and promote modernisation and the restoration of a stable form of democracy.[5] The Ayub Khan regime was also supported by foreign governments such as the United States.[5]

text: Further reading[edit]

text:
Maya Tudor, "The Promise of Power: The Origins of Democracy in India and Autocracy in Pakistan."(Cambridge University Press, 2013).
Aqil Shah, "Army and Democracy: Military Politics in Pakistan" (Harvard University Press, 2014)
K.B. Sayeed, "The collapse of Parliamentary Democracy in Pakistan," Middle East Journal, 13.4 (1959), 389–406

tag: ul


document_title: NetBIOS

question_text: which protocol provides names and name resolution for workgroups in windows

text: NetBIOS

text: History and terminology[edit]

text: NetBIOS is an OSI Session Layer 5 Protocol and a service that allows applications on computers to communicate with one another over a local area network (LAN). It is a non-routable Protocol and NetBIOS stands for Network Basic Input/Output System. NetBIOS was developed in 1983 by Sytek Inc. as an API for software communication over IBM PC Network LAN technology.[1] On PC-Network, as an API alone, NetBIOS relied on proprietary Sytek networking protocols for communication over the wire.[citation needed] Despite supporting a maximum of 80 PCs in a LAN, NetBIOS became an industry standard.[1]

text: In 1985, IBM went forward with the token ring network scheme and a NetBIOS emulator was produced to allow NetBIOS-aware applications from the PC-Network era to work over this new design. This emulator, named NetBIOS Extended User Interface (NetBEUI), expanded the base NetBIOS API with, among other things, the ability to deal with the greater node capacity of token ring. A new networking protocol, NBF, was simultaneously produced to allow NetBEUI (NetBIOS) to provide its services over token ring – specifically, at the IEEE 802.2 Logical Link Control layer.

text: In 1985, Microsoft created a NetBIOS implementation for its MS-Net networking technology. As in the case of IBM's token ring, the services of Microsoft's NetBIOS implementation were provided over the IEEE 802.2 Logical Link Control layer by the NBF protocol.[citation needed] Until Microsoft adopted Domain Name System (DNS) resolution of hostnames Microsoft operating systems used NetBIOS to resolve names in Windows client-server networks.[1]

text: In 1986, Novell released Advanced Novell NetWare 2.0 featuring the company's own NetBIOS emulator. Its services were encapsulated within NetWare's IPX/SPX protocol using the NetBIOS over IPX/SPX (NBX) protocol.

text: In 1987, a method of encapsulating NetBIOS in TCP and UDP packets, NetBIOS over TCP/IP (NBT), was published. It was described in RFC 1001 ("Protocol Standard for a NetBIOS Service on a TCP/UDP Transport: Concepts and Methods") and RFC 1002 ("Protocol Standard for a NetBIOS Service on a TCP/UDP Transport: Detailed Specifications"). The NBT protocol was developed in order to "allow an implementation [of NetBIOS applications] to be built on virtually any type of system where the TCP/IP protocol suite is available," and to "allow NetBIOS interoperation in the Internet."

text: After the PS/2 computer hit the market in 1987, IBM released the PC LAN Support Program, which included a driver for NetBIOS.

text: Worth noting is the popular confusion between the names NetBIOS and NetBEUI. NetBEUI originated strictly as the moniker for IBM's enhanced 1985 NetBIOS emulator for token ring. The name NetBEUI should have died there, considering that at the time, the NetBIOS implementations by other companies were known simply as NetBIOS regardless of whether they incorporated the API extensions found in that emulator. For MS-Net, however, Microsoft elected to name its implementation of the NBF protocol "NetBEUI" – literally naming its implementation of the transport protocol after IBM's second version of the API. Consequently, even today, Microsoft file and printer sharing over Ethernet continues to be called NetBEUI, with the name NetBIOS commonly used only in reference to file and printer sharing over TCP/IP. In truth, the former is the NetBIOS Frames protocol (NBF), and the latter is NetBIOS over TCP/IP (NBT).

text: Since its original publishing in a technical reference book from IBM, the NetBIOS API specification has become a de facto standard.

text: Services[edit]

text: NetBIOS provides three distinct services:

text:
Name service (NetBIOS-NS) for name registration and resolution.
Datagram distribution service (NetBIOS-DGM) for connectionless communication.
Session service (NetBIOS-SSN) for connection-oriented communication.

text: (Note: SMB, an upper layer, is a service that runs on top of the Session Service and the Datagram service, and is not to be confused as a necessary and integral part of NetBIOS itself. It can now run atop TCP with a small adaptation layer that adds a packet length to each SMB message; this is necessary because TCP only provides a byte-stream service with no notion of packet boundaries.)

text: Name service[edit]

text: In order to start sessions or distribute datagrams, an application must register its NetBIOS name using the name service. NetBIOS names are 16 octets in length and vary based on the particular implementation. Frequently, the 16th octet, called the NetBIOS Suffix, designates the type of resource, and can be used to tell other applications what type of services the system offers. In NBT, the name service operates on UDP port 137 (TCP port 137 can also be used, but rarely is).

text: The name service primitives offered by NetBIOS are:

text:
Add name – registers a NetBIOS name.
Add group name – registers a NetBIOS "group" name.
Delete name – un-registers a NetBIOS name or group name.
Find name – looks up a NetBIOS name on the network.

text: NetBIOS name resolution is not supported by Microsoft for Internet Protocol Version 6 (IPv6).

text: Datagram distribution service[edit]

text: Datagram mode is connectionless; the application is responsible for error detection and recovery. In NBT, the datagram service runs on UDP port 138.

text: The datagram service primitives offered by NetBIOS are:

text:
Send Datagram – send a datagram to a remote NetBIOS name.
Send Broadcast Datagram – send a datagram to all NetBIOS names on the network.
Receive Datagram – wait for a packet to arrive from a Send Datagram operation.
Receive Broadcast Datagram – wait for a packet to arrive from a Send Broadcast Datagram operation.

text: Session service[edit]

text: Session mode lets two computers establish a connection, allows messages to span multiple packets, and provides error detection and recovery. In NBT, the session service runs on TCP port 139.

text: The session service primitives offered by NetBIOS are:

text:
Call – opens a session to a remote NetBIOS name.
Listen – listen for attempts to open a session to a NetBIOS name.
Hang Up – close a session.
Send – sends a packet to the computer on the other end of a session.
Send No Ack – like Send, but doesn't require an acknowledgment.
Receive – wait for a packet to arrive from a Send on the other end of a session.

text: In the original protocol used to implement NetworkBIOS services on PC-Network, to establish a session, the initiating computer sends an Open request which is answered by an Open acknowledgment. The computer that started the session will then send a Session Request packet which will prompt either a Session Accept or Session Reject packet.

text: During an established session, each transmitted packet is answered by either a positive-acknowledgment (ACK) or negative-acknowledgment (NAK) response. A NAK will prompt retransmission of the data. Sessions are closed by the non-initiating computer by sending a close request. The computer that started the session will reply with a close response which prompts the final session closed packet.

text: NetBIOS name vs Internet host name[edit]

text: When NetBIOS is run in conjunction with Internet protocols (e.g., NBT), each computer may have multiple names: one or more NetBIOS name service names and one or more Internet host names.

text: NetBIOS name[edit]

text: The NetBIOS name is 16 ASCII characters, however Microsoft limits the host name to 15 characters and reserves the 16th character as a NetBIOS Suffix.[citation needed][2] This suffix describes the service or name record type such as host record, master browser record, or domain controller record or other services. The host name (or short host name) is specified when Windows networking is installed/configured, the suffixes registered are determined by the individual services supplied by the host. In order to connect to a computer running TCP/IP via its NetBIOS name, the name must be resolved to a network address. Today this is usually an IP address (the NetBIOS name to IP address resolution is often done by either broadcasts or a WINS Server – NetBIOS Name Server). A computer's NetBIOS name is often the same as that computer's host name (see below), although truncated to 15 characters, but it may also be completely different.

text: NetBIOS names are a sequence of alphanumeric characters. The following characters are explicitly not permitted: \/:*?"<>|. Since Windows 2000, NetBIOS names also had to comply with restrictions on DNS names: they cannot consist entirely of digits, and the hyphen ("-") or full-stop (".") characters may not appear as the first or last character. Since Windows 2000, Microsoft has advised against including any full-stop (".") characters in NetBIOS names, such that applications can use the presence of a full-stop to distinguish domain names from NetBIOS names.[3]

text: The Windows LMHOSTS file provides a NetBIOS name resolution method that can be used for small networks that do not use a WINS server.

text: Internet host name[edit]

text: A Windows machine's NetBIOS name is not to be confused with the computer's Internet host name. Generally a computer running Internet protocols (whether it is a Windows machine or not) has a host name (also sometimes called a machine name). Originally these names were stored in and provided by a hosts file but today most such names are part of the hierarchical Domain Name System (DNS). Generally the host name of a Windows computer is based on the NetBIOS name plus the Primary DNS Suffix, which are both set in the System Properties dialog box.

text: There may also be connection-specific suffixes which can be viewed or changed on the DNS tab in Control Panel → Network → TCP/IP → Advanced Properties. Host names are used by applications such as telnet, ftp, web browsers, etc. To connect to a computer running the TCP/IP protocol using its name, the host name must be resolved into an IP address, typically by a DNS server.

text: Node types[edit]

text: The node type of a networked computer relates to the way it resolves NetBIOS names to IP addresses. There are four node types.

text:
B-node: 0x01 Broadcast
P-node: 0x02 Peer (WINS only)
M-node: 0x04 Mixed (broadcast, then WINS)
H-node: 0x08 Hybrid (WINS, then broadcast)

text:
The node type in use is displayed by opening a command line and typing ipconfig /all.
A Windows computer registry may also be configured in such a way as to display "unknown" for the node type.

text: NetBIOS Suffixes[edit]

text: The NetBIOS Suffix, alternately called the NetBIOS End Character (endchar), is the 16th character of a NetBIOS name and indicates service type for the registered name. The number of record types is limited to 255; some commonly used values are:

text: For unique names:

text:
00: Workstation Service (workstation name)
03: Windows Messenger service
06: Remote Access Service
20: File Service (also called Host Record)
21: Remote Access Service client
1B: Domain Master Browser – Primary Domain Controller for a domain
1D: Master Browser

text: For group names:

text:
00: Workstation Service (workgroup/domain name)
1C: Domain Controllers for a domain (group record with up to 25 IP addresses)
1E: Browser Service Elections


question_text: who sang don't know what you got till it's gone

question_tokens: who sang do n 't know what you got till it 's gone

text:
"Don't Know What You Got (Till It's Gone)"

Single by Cinderella

from the album Long Cold Winter

Released
August 1988

Format
7", 12"

Genre
Glam metal[1][2]

Length
5:55

Label
Mercury

Songwriter(s)
Tom Keifer

Producer(s)
Andy Johns, Cinderella

Cinderella singles chronology

"Gypsy Road"
(1988)
"Don't Know What You Got (Till It's Gone)"
(1988)
"Coming Home"
(1989)

"Gypsy Road"
(1988)
"Don't Know What You Got (Till It's Gone)"
(1988)
"Coming Home"
(1989)

tag: table

text: "Don't Know What You Got (Till It's Gone)" is a power ballad[2][3] written and performed by the glam metal band Cinderella, from their second album Long Cold Winter. Released in August 1988, it was their most successful single, peaking at number 12 on US Billboard Hot 100 in November 1988.

text: The music video for this song was filmed at Mono Lake[2] and Bodie, California. This fact is revealed in the Tales From the Gypsy Road video collection.

text: Chart performance[edit]

text:
Chart (1988–1989)
Peak
position

Canada Top Singles (RPM)[4]
68

UK Singles (Official Charts Company)[5]
54

US Billboard Album Rock Tracks[6]
10

US Billboard Hot 100[6]
12

US Cash Box[7]
17


document_title: Atmosphere of Earth

question_text: what are the 5 layers of earth atmosphere

text: Atmosphere of Earth

text: Composition

text: The three major constituents of Earth's atmosphere, are nitrogen, oxygen, and argon. Water vapor accounts for roughly 0.25% of the atmosphere by mass. The concentration of water vapor (a greenhouse gas) varies significantly from around 10 ppm by volume in the coldest portions of the atmosphere to as much as 5% by volume in hot, humid air masses, and concentrations of other atmospheric gases are typically quoted in terms of dry air (without water vapor).[5] The remaining gases are often referred to as trace gases,[6] among which are the greenhouse gases, principally carbon dioxide, methane, nitrous oxide, and ozone. Filtered air includes trace amounts of many other chemical compounds. Many substances of natural origin may be present in locally and seasonally variable small amounts as aerosols in an unfiltered air sample, including dust of mineral and organic composition, pollen and spores, sea spray, and volcanic ash. Various industrial pollutants also may be present as gases or aerosols, such as chlorine (elemental or in compounds), fluorine compounds and elemental mercury vapor. Sulfur compounds such as hydrogen sulfide and sulfur dioxide (SO2) may be derived from natural sources or from industrial air pollution.

text:
Major constituents of dry air, by volume[7]

Gas
Volume(A)

Name
Formula
in ppmv(B)
in %

Nitrogen
N2
780,840
78.084

Oxygen
O2
209,460
20.946

Argon
Ar
9,340
0.9340

Carbon dioxide
CO2
400
0.04[8]

Neon
Ne
18.18
0.001818

Helium
He
5.24
0.000524

Methane
CH4
1.79
0.000179

Not included in above dry atmosphere:

Water vapor(C)
H2O
10–50,000(D)
0.001%–5%(D)

notes:
(A) volume fraction is equal to mole fraction for ideal gas only,
    also see volume (thermodynamics)
(B) ppmv: parts per million by volume
(C) Water vapor is about 0.25% by mass over full atmosphere
(D) Water vapor strongly varies locally[5]

text: The relative concentration of gasses remains constant until about 10,000 m (33,000 ft).[9]

text: Structure of the atmosphere

text: Principal layers

text: In general, air pressure and density decrease with altitude in the atmosphere. However, temperature has a more complicated profile with altitude, and may remain relatively constant or even increase with altitude in some regions (see the temperature section, below). Because the general pattern of the temperature/altitude profile is constant and measurable by means of instrumented balloon soundings, the temperature behavior provides a useful metric to distinguish atmospheric layers. In this way, Earth's atmosphere can be divided (called atmospheric stratification) into five main layers. Excluding the exosphere, the atmosphere has four primary layers, which are the troposphere, stratosphere, mesosphere, and thermosphere.[10] From highest to lowest, the five main layers are:

text:
Exosphere: 700 to 10,000 km (440 to 6,200 miles)
Thermosphere: 80 to 700 km (50 to 440 miles)[11]
Mesosphere: 50 to 80 km (31 to 50 miles)
Stratosphere: 12 to 50 km (7 to 31 miles)
Troposphere: 0 to 12 km (0 to 7 miles)[12]

text: Exosphere

text: The exosphere is the outermost layer of Earth's atmosphere (i.e. the upper limit of the atmosphere). It extends from the exobase, which is located at the top of the thermosphere at an altitude of about 700 km above sea level, to about 10,000 km (6,200 mi; 33,000,000 ft) where it merges into the solar wind.

text: This layer is mainly composed of extremely low densities of hydrogen, helium and several heavier molecules including nitrogen, oxygen and carbon dioxide closer to the exobase. The atoms and molecules are so far apart that they can travel hundreds of kilometers without colliding with one another. Thus, the exosphere no longer behaves like a gas, and the particles constantly escape into space. These free-moving particles follow ballistic trajectories and may migrate in and out of the magnetosphere or the solar wind.

text: The exosphere is located too far above Earth for any meteorological phenomena to be possible. However, the aurora borealis and aurora australis sometimes occur in the lower part of the exosphere, where they overlap into the thermosphere. The exosphere contains most of the satellites orbiting Earth.

text: Thermosphere

text: The thermosphere is the second-highest layer of Earth's atmosphere. It extends from the mesopause (which separates it from the mesosphere) at an altitude of about 80 km (50 mi; 260,000 ft) up to the thermopause at an altitude range of 500–1000 km (310–620 mi; 1,600,000–3,300,000 ft). The height of the thermopause varies considerably due to changes in solar activity.[11] Because the thermopause lies at the lower boundary of the exosphere, it is also referred to as the exobase. The lower part of the thermosphere, from 80 to 550 kilometres (50 to 342 mi) above Earth's surface, contains the ionosphere.

text: The temperature of the thermosphere gradually increases with height. Unlike the stratosphere beneath it, wherein a temperature inversion is due to the absorption of radiation by ozone, the inversion in the thermosphere occurs due to the extremely low density of its molecules. The temperature of this layer can rise as high as 1500 °C (2700 °F), though the gas molecules are so far apart that its temperature in the usual sense is not very meaningful. The air is so rarefied that an individual molecule (of oxygen, for example) travels an average of 1 kilometre (0.62 mi; 3300 ft) between collisions with other molecules.[13] Although the thermosphere has a high proportion of molecules with high energy, it would not feel hot to a human in direct contact, because its density is too low to conduct a significant amount of energy to or from the skin.

text: This layer is completely cloudless and free of water vapor. However, non-hydrometeorological phenomena such as the aurora borealis and aurora australis are occasionally seen in the thermosphere. The International Space Station orbits in this layer, between 350 and 420 km (220 and 260 mi).

text: Mesosphere

text: The mesosphere is the third highest layer of Earth's atmosphere, occupying the region above the stratosphere and below the thermosphere. It extends from the stratopause at an altitude of about 50 km (31 mi; 160,000 ft) to the mesopause at 80–85 km (50–53 mi; 260,000–280,000 ft) above sea level.

text: Temperatures drop with increasing altitude to the mesopause that marks the top of this middle layer of the atmosphere. It is the coldest place on Earth and has an average temperature around −85 °C (−120 °F; 190 K).[14][15]

text: Just below the mesopause, the air is so cold that even the very scarce water vapor at this altitude can be sublimated into polar-mesospheric noctilucent clouds. These are the highest clouds in the atmosphere and may be visible to the naked eye if sunlight reflects off them about an hour or two after sunset or a similar length of time before sunrise. They are most readily visible when the Sun is around 4 to 16 degrees below the horizon. Lightning-induced discharges known as transient luminous events (TLEs) occasionally form in the mesosphere above tropospheric thunderclouds. The mesosphere is also the layer where most meteors burn up upon atmospheric entrance. It is too high above Earth to be accessible to jet-powered aircraft and balloons, and too low to permit orbital spacecraft. The mesosphere is mainly accessed by sounding rockets and rocket-powered aircraft.

text: Stratosphere

text: The stratosphere is the second-lowest layer of Earth's atmosphere. It lies above the troposphere and is separated from it by the tropopause. This layer extends from the top of the troposphere at roughly 12 km (7.5 mi; 39,000 ft) above Earth's surface to the stratopause at an altitude of about 50 to 55 km (31 to 34 mi; 164,000 to 180,000 ft).

text: The atmospheric pressure at the top of the stratosphere is roughly 1/1000 the pressure at sea level. It contains the ozone layer, which is the part of Earth's atmosphere that contains relatively high concentrations of that gas. The stratosphere defines a layer in which temperatures rise with increasing altitude. This rise in temperature is caused by the absorption of ultraviolet radiation (UV) radiation from the Sun by the ozone layer, which restricts turbulence and mixing. Although the temperature may be −60 °C (−76 °F; 210 K) at the tropopause, the top of the stratosphere is much warmer, and may be near 0 °C.[16]

text: The stratospheric temperature profile creates very stable atmospheric conditions, so the stratosphere lacks the weather-producing air turbulence that is so prevalent in the troposphere. Consequently, the stratosphere is almost completely free of clouds and other forms of weather. However, polar stratospheric or nacreous clouds are occasionally seen in the lower part of this layer of the atmosphere where the air is coldest. The stratosphere is the highest layer that can be accessed by jet-powered aircraft.

text: Troposphere

text: The troposphere is the lowest layer of Earth's atmosphere. It extends from Earth's surface to an average height of about 12 km, although this altitude actually varies from about 9 km (30,000 ft) at the poles to 17 km (56,000 ft) at the equator,[12] with some variation due to weather. The troposphere is bounded above by the tropopause, a boundary marked in most places by a temperature inversion (i.e. a layer of relatively warm air above a colder one), and in others by a zone which is isothermal with height.[17][18]

text: Although variations do occur, the temperature usually declines with increasing altitude in the troposphere because the troposphere is mostly heated through energy transfer from the surface. Thus, the lowest part of the troposphere (i.e. Earth's surface) is typically the warmest section of the troposphere. This promotes vertical mixing (hence the origin of its name in the Greek word τρόπος, tropos, meaning "turn"). The troposphere contains roughly 80% of the mass of Earth's atmosphere.[19] The troposphere is denser than all its overlying atmospheric layers because a larger atmospheric weight sits on top of the troposphere and causes it to be most severely compressed. Fifty percent of the total mass of the atmosphere is located in the lower 5.6 km (18,000 ft) of the troposphere.

text: Nearly all atmospheric water vapor or moisture is found in the troposphere, so it is the layer where most of Earth's weather takes place. It has basically all the weather-associated cloud genus types generated by active wind circulation, although very tall cumulonimbus thunder clouds can penetrate the tropopause from below and rise into the lower part of the stratosphere. Most conventional aviation activity takes place in the troposphere, and it is the only layer that can be accessed by propeller-driven aircraft.

text: Other layers

text: Within the five principal layers that are largely determined by temperature, several secondary layers may be distinguished by other properties:

text:
The ozone layer is contained within the stratosphere. In this layer ozone concentrations are about 2 to 8 parts per million, which is much higher than in the lower atmosphere but still very small compared to the main components of the atmosphere. It is mainly located in the lower portion of the stratosphere from about 15–35 km (9.3–21.7 mi; 49,000–115,000 ft), though the thickness varies seasonally and geographically. About 90% of the ozone in Earth's atmosphere is contained in the stratosphere.
The ionosphere is a region of the atmosphere that is ionized by solar radiation. It is responsible for auroras. During daytime hours, it stretches from 50 to 1,000 km (31 to 621 mi; 160,000 to 3,280,000 ft) and includes the mesosphere, thermosphere, and parts of the exosphere. However, ionization in the mesosphere largely ceases during the night, so auroras are normally seen only in the thermosphere and lower exosphere. The ionosphere forms the inner edge of the magnetosphere. It has practical importance because it influences, for example, radio propagation on Earth.
The homosphere and heterosphere are defined by whether the atmospheric gases are well mixed. The surface-based homosphere includes the troposphere, stratosphere, mesosphere, and the lowest part of the thermosphere, where the chemical composition of the atmosphere does not depend on molecular weight because the gases are mixed by turbulence.[21] This relatively homogeneous layer ends at the turbopause found at about 100 km (62 mi; 330,000 ft), the very edge of space itself as accepted by the FAI, which places it about 20 km (12 mi; 66,000 ft) above the mesopause.

text: The planetary boundary layer is the part of the troposphere that is closest to Earth's surface and is directly affected by it, mainly through turbulent diffusion. During the day the planetary boundary layer usually is well-mixed, whereas at night it becomes stably stratified with weak or intermittent mixing. The depth of the planetary boundary layer ranges from as little as about 100 metres (330 ft) on clear, calm nights to 3,000 m (9,800 ft) or more during the afternoon in dry regions.

text: The average temperature of the atmosphere at Earth's surface is 14 °C (57 °F; 287 K)[22] or 15 °C (59 °F; 288 K),[23] depending on the reference.[24][25][26]

text: Physical properties

text: Pressure and thickness

text: The average atmospheric pressure at sea level is defined by the International Standard Atmosphere as 101325 pascals (760.00 Torr; 14.6959 psi; 760.00 mmHg). This is sometimes referred to as a unit of standard atmospheres (atm). Total atmospheric mass is 5.1480×1018 kg (1.135×1019 lb),[28] about 2.5% less than would be inferred from the average sea level pressure and Earth's area of 51007.2 megahectares, this portion being displaced by Earth's mountainous terrain. Atmospheric pressure is the total weight of the air above unit area at the point where the pressure is measured. Thus air pressure varies with location and weather.

text: If the entire mass of the atmosphere had a uniform density from sea level, it would terminate abruptly at an altitude of 8.50 km (27,900 ft). It actually decreases exponentially with altitude, dropping by half every 5.6 km (18,000 ft) or by a factor of 1/e every 7.64 km (25,100 ft), the average scale height of the atmosphere below 70 km (43 mi; 230,000 ft). However, the atmosphere is more accurately modeled with a customized equation for each layer that takes gradients of temperature, molecular composition, solar radiation and gravity into account.

text: In summary, the mass of Earth's atmosphere is distributed approximately as follows:[29]

text:
50% is below 5.6 km (18,000 ft).
90% is below 16 km (52,000 ft).
99.99997% is below 100 km (62 mi; 330,000 ft), the Kármán line. By international convention, this marks the beginning of space where human travelers are considered astronauts.

text: By comparison, the summit of Mt. Everest is at 8,848 m (29,029 ft); commercial airliners typically cruise between 10 km (33,000 ft) and 13 km (43,000 ft) where the thinner air improves fuel economy; weather balloons reach 30.4 km (100,000 ft) and above; and the highest X-15 flight in 1963 reached 108.0 km (354,300 ft).

text: Even above the Kármán line, significant atmospheric effects such as auroras still occur. Meteors begin to glow in this region, though the larger ones may not burn up until they penetrate more deeply. The various layers of Earth's ionosphere, important to HF radio propagation, begin below 100 km and extend beyond 500 km. By comparison, the International Space Station and Space Shuttle typically orbit at 350–400 km, within the F-layer of the ionosphere where they encounter enough atmospheric drag to require reboosts every few months. Depending on solar activity, satellites can experience noticeable atmospheric drag at altitudes as high as 700–800 km.

text: Temperature and speed of sound

text: The division of the atmosphere into layers mostly by reference to temperature is discussed above. Temperature decreases with altitude starting at sea level, but variations in this trend begin above 11 km, where the temperature stabilizes through a large vertical distance through the rest of the troposphere. In the stratosphere, starting above about 20 km, the temperature increases with height, due to heating within the ozone layer caused by capture of significant ultraviolet radiation from the Sun by the dioxygen and ozone gas in this region. Still another region of increasing temperature with altitude occurs at very high altitudes, in the aptly-named thermosphere above 90 km.

text: Because in an ideal gas of constant composition the speed of sound depends only on temperature and not on the gas pressure or density, the speed of sound in the atmosphere with altitude takes on the form of the complicated temperature profile (see illustration to the right), and does not mirror altitudinal changes in density or pressure.

text: Density and mass

text: The density of air at sea level is about 1.2 kg/m3 (1.2 g/L, 0.0012 g/cm3). Density is not measured directly but is calculated from measurements of temperature, pressure and humidity using the equation of state for air (a form of the ideal gas law). Atmospheric density decreases as the altitude increases. This variation can be approximately modeled using the barometric formula. More sophisticated models are used to predict orbital decay of satellites.

text: The average mass of the atmosphere is about 5 quadrillion (5×1015) tonnes or 1/1,200,000 the mass of Earth. According to the American National Center for Atmospheric Research, "The total mean mass of the atmosphere is 5.1480×1018 kg with an annual range due to water vapor of 1.2 or 1.5×1015 kg, depending on whether surface pressure or water vapor data are used; somewhat smaller than the previous estimate. The mean mass of water vapor is estimated as 1.27×1016 kg and the dry air mass as 5.1352 ±0.0003×1018 kg."

text: Optical properties

text: This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (October 2013) (Learn how and when to remove this template message)

text: Solar radiation (or sunlight) is the energy Earth receives from the Sun. Earth also emits radiation back into space, but at longer wavelengths that we cannot see. Part of the incoming and emitted radiation is absorbed or reflected by the atmosphere. In May 2017, glints of light, seen as twinkling from an orbiting satellite a million miles away, were found to be reflected light from ice crystals in the atmosphere.[31][32]

text: Scattering

text: When light passes through Earth's atmosphere, photons interact with it through scattering. If the light does not interact with the atmosphere, it is called direct radiation and is what you see if you were to look directly at the Sun. Indirect radiation is light that has been scattered in the atmosphere. For example, on an overcast day when you cannot see your shadow there is no direct radiation reaching you, it has all been scattered. As another example, due to a phenomenon called Rayleigh scattering, shorter (blue) wavelengths scatter more easily than longer (red) wavelengths. This is why the sky looks blue; you are seeing scattered blue light. This is also why sunsets are red. Because the Sun is close to the horizon, the Sun's rays pass through more atmosphere than normal to reach your eye. Much of the blue light has been scattered out, leaving the red light in a sunset.

text: Absorption

text: Different molecules absorb different wavelengths of radiation. For example, O2 and O3 absorb almost all wavelengths shorter than 300 nanometers. Water (H2O) absorbs many wavelengths above 700 nm. When a molecule absorbs a photon, it increases the energy of the molecule. This heats the atmosphere, but the atmosphere also cools by emitting radiation, as discussed below.

text: The combined absorption spectra of the gases in the atmosphere leave "windows" of low opacity, allowing the transmission of only certain bands of light. The optical window runs from around 300 nm (ultraviolet-C) up into the range humans can see, the visible spectrum (commonly called light), at roughly 400–700 nm and continues to the infrared to around 1100 nm. There are also infrared and radio windows that transmit some infrared and radio waves at longer wavelengths. For example, the radio window runs from about one centimeter to about eleven-meter waves.

text: Emission

text: Emission is the opposite of absorption, it is when an object emits radiation. Objects tend to emit amounts and wavelengths of radiation depending on their "black body" emission curves, therefore hotter objects tend to emit more radiation, with shorter wavelengths. Colder objects emit less radiation, with longer wavelengths. For example, the Sun is approximately 6,000 K (5,730 °C; 10,340 °F), its radiation peaks near 500 nm, and is visible to the human eye. Earth is approximately 290 K (17 °C; 62 °F), so its radiation peaks near 10,000 nm, and is much too long to be visible to humans.

text: Because of its temperature, the atmosphere emits infrared radiation. For example, on clear nights Earth's surface cools down faster than on cloudy nights. This is because clouds (H2O) are strong absorbers and emitters of infrared radiation. This is also why it becomes colder at night at higher elevations.

text: The greenhouse effect is directly related to this absorption and emission effect. Some gases in the atmosphere absorb and emit infrared radiation, but do not interact with sunlight in the visible spectrum. Common examples of these are CO2 and H2O.

text: Refractive index

text: The refractive index of air is close to, but just greater than 1. Systematic variations in refractive index can lead to the bending of light rays over long optical paths. One example is that, under some circumstances, observers onboard ships can see other vessels just over the horizon because light is refracted in the same direction as the curvature of Earth's surface.

text: The refractive index of air depends on temperature, giving rise to refraction effects when the temperature gradient is large. An example of such effects is the mirage.

text: Circulation

text: Atmospheric circulation is the large-scale movement of air through the troposphere, and the means (with ocean circulation) by which heat is distributed around Earth. The large-scale structure of the atmospheric circulation varies from year to year, but the basic structure remains fairly constant because it is determined by Earth's rotation rate and the difference in solar radiation between the equator and poles.

text: Evolution of Earth's atmosphere

text: Earliest atmosphere

text: The first atmosphere consisted of gases in the solar nebula, primarily hydrogen. There were probably simple hydrides such as those now found in the gas giants (Jupiter and Saturn), notably water vapor, methane and ammonia.[33]

text: Second atmosphere

text: Outgassing from volcanism, supplemented by gases produced during the late heavy bombardment of Earth by huge asteroids, produced the next atmosphere, consisting largely of nitrogen plus carbon dioxide and inert gases.[33] A major part of carbon-dioxide emissions dissolved in water and reacted with metals such as calcium and magnesium during weathering of crustal rocks to form carbonates that were deposited as sediments. Water-related sediments have been found that date from as early as 3.8 billion years ago.[34]

text: About 3.4 billion years ago, nitrogen formed the major part of the then stable "second atmosphere". The influence of life has to be taken into account rather soon in the history of the atmosphere, because hints of early life-forms appear as early as 3.5 billion years ago.[35] How Earth at that time maintained a climate warm enough for liquid water and life, if the early Sun put out 30% lower solar radiance than today, is a puzzle known as the "faint young Sun paradox".

text: The geological record however shows a continuous relatively warm surface during the complete early temperature record of Earth – with the exception of one cold glacial phase about 2.4 billion years ago. In the late Archean Eon an oxygen-containing atmosphere began to develop, apparently produced by photosynthesizing cyanobacteria (see Great Oxygenation Event), which have been found as stromatolite fossils from 2.7 billion years ago. The early basic carbon isotopy (isotope ratio proportions) strongly suggests conditions similar to the current, and that the fundamental features of the carbon cycle became established as early as 4 billion years ago.

text: Ancient sediments in the Gabon dating from between about 2,150 and 2,080 million years ago provide a record of Earth's dynamic oxygenation evolution. These fluctuations in oxygenation were likely driven by the Lomagundi carbon isotope excursion.[36]

text: Third atmosphere

text: The constant re-arrangement of continents by plate tectonics influences the long-term evolution of the atmosphere by transferring carbon dioxide to and from large continental carbonate stores. Free oxygen did not exist in the atmosphere until about 2.4 billion years ago during the Great Oxygenation Event and its appearance is indicated by the end of the banded iron formations.

text: Before this time, any oxygen produced by photosynthesis was consumed by oxidation of reduced materials, notably iron. Molecules of free oxygen did not start to accumulate in the atmosphere until the rate of production of oxygen began to exceed the availability of reducing materials that removed oxygen. This point signifies a shift from a reducing atmosphere to an oxidizing atmosphere. O2 showed major variations until reaching a steady state of more than 15% by the end of the Precambrian.[39] The following time span from 541 million years ago to the present day is the Phanerozoic Eon, during the earliest period of which, the Cambrian, oxygen-requiring metazoan life forms began to appear.

text: The amount of oxygen in the atmosphere has fluctuated over the last 600 million years, reaching a peak of about 30% around 280 million years ago, significantly higher than today's 21%. Two main processes govern changes in the atmosphere: Plants use carbon dioxide from the atmosphere, releasing oxygen. Breakdown of pyrite and volcanic eruptions release sulfur into the atmosphere, which oxidizes and hence reduces the amount of oxygen in the atmosphere. However, volcanic eruptions also release carbon dioxide, which plants can convert to oxygen. The exact cause of the variation of the amount of oxygen in the atmosphere is not known. Periods with much oxygen in the atmosphere are associated with rapid development of animals. Today's atmosphere contains 21% oxygen, which is great enough for this rapid development of animals.[40]

text: Air pollution

text: Air pollution is the introduction into the atmosphere of chemicals, particulate matter or biological materials that cause harm or discomfort to organisms.[41] Stratospheric ozone depletion is caused by air pollution, chiefly from chlorofluorocarbons and other ozone-depleting substances.

text: The scientific consensus is that the anthropogenic greenhouse gases currently accumulating in the atmosphere are the main cause of global warming.[42]

text: Images from space

text: On October 19, 2015 NASA started a website containing daily images of the full sunlit side of Earth on http://epic.gsfc.nasa.gov/. The images are taken from the Deep Space Climate Observatory (DSCOVR) and show Earth as it rotates during a day.[43]

text:
Blue light is scattered more than other wavelengths by the gases in the atmosphere, giving Earth a blue halo when seen from space.

The geomagnetic storms cause beautiful displays of aurora across the atmosphere.

Limb view, of Earth's atmosphere. Colors roughly denote the layers of the atmosphere.

This image shows the Moon at the centre, with the limb of Earth near the bottom transitioning into the orange-colored troposphere. The troposphere ends abruptly at the tropopause, which appears in the image as the sharp boundary between the orange- and blue-colored atmosphere. The silvery-blue noctilucent clouds extend far above Earth's troposphere.

Earth's atmosphere backlit by the Sun in an eclipse observed from deep space onboard Apollo 12 in 1969.


document_title: Big Brother (U.S. TV series)

question_text: who has played big brother the most times

text: Big Brother (U.S. TV series)

text: History[edit]

text: Series[edit]

text: The series was bought by CBS in early 2000 for an estimated $20 million.[5] The United States version of the series officially premiered on July 5, 2000 when the original ten housemates entered the house.[6] Since its inception, the show has been hosted by television personality Julie Chen. It is produced by Allison Grodner and Rich Meehan for Fly on the Wall Entertainment and Endemol Shine North America (formerly Endemol USA).[7] The success of the series has spawned several spin-offs. The series airs once a year, during the summer, with the exception of the ninth season which aired in spring of 2008 and the Over the Top spinoff series broadcasting in fall 2016. Currently, 19 seasons of the show have aired, along with one digital season.[8] The show has aired a total of 545 episodes since it premiered, with the September 5, 2013 airing marking the 500th episode.[9] To date, there have been a total of 253 HouseGuests compete in the series. Upon entering the house, the HouseGuests who leave the house without permission are not allowed to return. Should a HouseGuest break the rules set in the house, they can be expelled from the house. To date, there have been a total of four HouseGuests expelled from the house because of acts of violence and/or rule-breaking. There have only been three HouseGuests who have voluntarily left the game for reasons relating to personal matters.

text: Companion shows[edit]

text: Since its premiere, there have been numerous companion programs to the show. In 2004, the web series House Calls: The Big Brother Talk Show (2004–08) began airing.[10] The series, which lasted for thirty minutes and aired on weeknights, allowed fans to call in and discuss the events of the game.[11] This made House Calls the first live Internet talk show produced exclusively for a television network.[12] The series was initially hosted by Gretchen Massey and Big Brother 3 (2002) HouseGuest Marcellas Reynolds during its first two seasons.[13] Beginning with the show's third season, a new co-host was featured on the series each day, with some returning more than once.[14] During the show's fifth and sixth seasons, each co-host was given a designated day of the week to host alongside Gretchen.[15] Following the show's sixth season, it was confirmed that it would not be renewed.[16]

text: Big Brother: After Dark, a second companion series, was debuted in 2007 and aired on Showtime Too nightly from 12 a.m. to 3 a.m. Eastern Time.[17] The series continued this schedule until 2013, when it was moved to TVGN (now Pop).[18][19]

text: Former HouseGuest Jeff Schroeder began hosting the Big Brother: Live Chat online discussion show in 2012, where he interviewed the HouseGuests both before they enter the house and following their evictions. He also performed post-finale backyard interviews with the cast.[20] On August 10, 2017, Schroeder announced that he was moving to Colorado and would no longer be able to do the interviews.[21]

text: Spin-offs[edit]

text: There have been two spin-off editions of Big Brother. In October 2016, CBS premiered a spin-off web series, Big Brother: Over the Top, as an original series for CBS All Access. Unlike the flagship, television version, it was broadcast exclusively online with a shorter, 10-week season.[22][23]

text: The second spin-off, Celebrity Big Brother, is set to air in the winter of 2018 on CBS.

text: Though not an actual spin-off, the Canadian edition of the series is the first and currently only series to adopt the American format of Big Brother.[24] However, other franchises such as Big Brother Brasil soon adopted the Veto Competition, Have/Have-Nots, and Head of Household into their formate while still incorperating the international public vote format.[25]

text: Format[edit]

text: Big Brother is a game show in which a group of contestants, referred to as HouseGuests, live in a custom-built "house" (actually a set built on a CBS stage in Los Angeles, Stage 18 in recent editions), constantly under video surveillance.[26] While in the house, the contestants are completely isolated from the outside world, meaning no phone, television, internet, magazines, newspaper, or contact with those not in the house.[27] This rule could be broken, however, in the event of a medical injury, a family emergency or death.[28] The format of the series is mainly seen as a social experiment, and requires HouseGuests to interact with others who may have differing ideals, beliefs, and prejudices.[29][30] While a competition, the series allows viewers to witness the relationships formed in the house and the behavior of the HouseGuests.[31] Though locked in the house, the HouseGuests are free to quit the game, though will not be allowed entry back into the house.[32] Should a HouseGuest break the rules of the game, they could be expelled from the house, and unable to return.[33][34] The contestants compete for a grand prize of $500,000.[35][36]

text: Season 1[edit]

text: The premiere season used the original format of the series, which originated in the Netherlands. HouseGuests were required to nominate two of their fellow contestants for potential banishment, and the two with the most votes would be nominated.[37] Should multiple HouseGuests receive the most nominations, then more than two HouseGuests were marked for banishment.[38] This process was mandatory for all HouseGuests, and failure to comply could result in expulsion from the house.[39] The HouseGuests in these seasons were forbidden from discussing nominations, and doing so could result in punishment.[40][41] The public, through a vote conducted by phone, would vote to banish one of the nominated HouseGuests from the house, and the HouseGuest with the most votes from the viewers would be banished from the house.[42] When only three HouseGuests remained, the viewers would vote for which of them should win the series, and the HouseGuest with the most votes would become the winner.[38] The format, during that season, was plagued with a negative reception from both critics and viewers.[43]

text: Season 2–present[edit]

text: Having spent millions on the series, CBS issued a second season of the series and announced that various changes would occur with the format.[44] The current format of the series is focused more on competition and strategy than the original series. At the start of each week in the house, the HouseGuests compete for the title of Head of Household.[45] The Head of Household for each week is given luxuries such as their own personal bedroom and free laundry service, but is responsible for nominating two HouseGuests for eviction. The Head of Household would not be able to compete in the following week's Head of Household competition, meaning that a HouseGuest could not hold the title for two weeks in a row, except for the final week or other stated circumstances.[46][47] [48] All HouseGuests excluding the Head of Household and nominees later vote to determine which of the two nominees should be evicted, and the nominated HouseGuest who received the most votes is evicted during a live episode. If there is a tie in the voting, the reigning Head of Household is required to make the tie-breaker decision.[49] Unlike other versions of Big Brother, the HouseGuests may discuss the nomination and eviction process openly and freely. The HouseGuests also competed in Have-Not competitions, in which the losers were required to solely eat slop for the rest of the week, as well as sleep in a special bedroom.[50] Upon reaching a point in the game, the evicted HouseGuests go on to become members of the Jury; the Jury is responsible for choosing who wins the series. The members of the Jury are not shown any Diary Room interviews or any footage that may include strategy or details regarding nominations.[51] Once only two HouseGuests remain, the members of the Jury cast their votes for who should win the series.[52]

text: To keep the series intriguing, each season typically features a new twist to change the format of the game. This began with Big Brother 3 (2002) and the "Expect the Unexpected" twist.[53] Other seasons feature smaller twists than have a smaller impact on the game, usually affecting that sole week. The most notable example of this is Pandora's Box, a twist that originated in Big Brother 11 (2009).[54] The twist sees the current Head of Household for that week being tempted by the box, and can choose to either open the box or leave it. Should a HouseGuest choose to open Pandora's Box, both good and bad consequences could be unleashed into the house; these can affect not only the Head of Household but the other housemates.[55][56]Similar formats are applied in later seasons, for example, the Den of Temptation introduced in season 19. Secret powers have also appeared in the past. Mike Malin was the first HouseGuest to receive a secret power, earning the Coup d'État during Big Brother: All-Stars (2006).[57] The Coup d'État allowed the holder to remove one or both nominees from the block on eviction night, as well as choose who is nominated in their place.[58] Malin chose not to use the power, and it subsequently returned during Big Brother 11 (2009) when Jeff Schroeder was given the power by the viewers.[59] Matt Hoffman was given a Diamond Power of Veto during Big Brother 12 (2010), which allowed him to remove one HouseGuest from the block and choose the replacement nominee.[60] During Big Brother 14 (2012), HouseGuest Ian Terry won a second Power of Veto, which could be used the same as the normal Power of Veto.[61]

text: There have been many seasons in which there has been a twist that allows an evicted HouseGuest to return to the game as if they never left. This happened by either a vote or by a competition. From season 18 onward this was referred to as the Battle Back Competition. After being evicted the HouseGuests remained sequestered either separately from each other or (if occurring post-jury) together in the jury house. Those who elected to leave sequester or who leave the game voluntarily were ineligible to return. In Big Brother 3, the first four evictees competed in a competition where they were asked questions about how much they would give up to re-enter the house. The two who gave up the most faced a vote of the house as to who would return. In Big Brother 6, three of the first four evictees were voted on by an America's Vote where the winner returned to the house. In Big Brother 9 and Big Brother 13, the first few evictees were also voted on by the public. Then a house vote was held on whether to bring back the most recent evictee or the person America chose known only to them as the "mystery HouseGuest". During Big Brother 18 and Big Brother 19 there was a competition to determine who would return to the house

text: Jessie Godderz has made the most Big Brother appearances in the show's history, appearing in seasons 10 and 11 as a HouseGuest and in seasons 12–14 and 17–19 in a special guest appearance.

text: Victor Arroyo became the first HouseGuest to reenter the house for a third time in the same season while Paul Abrahamian became the first HouseGuest to make it to the final two twice but still not win.

text: Broadcast[edit]

text: Since its launch in the United States, Big Brother has aired on CBS.[62] The show is simulcast in Canada on Global.[63] The fourth and ninth seasons have both aired in the United Kingdom, the latter airing in the Spring season.[64] The first season featured a total of six episodes per week, though all future installments would air three nights per week.[65] Of these three episodes, the weekly eviction episode is the only one that is live; this is the only episode to feature host Julie Chen. This show generally airs on Thursdays.[66] To date, there have been a total of 558 episodes of the series to air.[67] With the exception of the ninth season, the series typically airs once a year during the Summer season.[68][69] The first fifteen seasons aired in standard definition, with the sixteenth season being the first to be produced in HD.[70][71] Before the series made the transfer, it was the last remaining regularly scheduled Primetime series to remain in standard definition.[72][73] CBS released the entire third season as a nine-disc set on Region 1 DVD.[74] This made it the first season to receive an official release, and has since become a rare item to find.[75] The fourth season saw the release of a two-disc highlights DVD, featuring previously unseen footage deemed too racy for the main broadcast.[76] To date, these are the only seasons to see a physical release. Beginning with the seventh season, all future seasons are available for purchase on digital retail sites.[77] With the fifteenth season, TVGN (now Pop) began airing re-runs of the series at later dates, making it the first season to be aired following its premiere; this continued with the sixteenth season.[78]

text: Subscribers to CBS All Access are able to stream the complete run of Big Brother, including the differently-formatted first season, and an episode of Big Brother 2 that did not air in most markets due to ongoing coverage of the September 11 attacks.

text: One of the main aspects of the series is the live feeds, in which viewers can view inside the house at any time.[79] The live feeds have been a part of the series since its inception, initially being offered as a free service during the first season.[80] From the second season onward, a subscription to the live feeds has been required, with the price ranging each year.[81] The first season's feeds were available on the show's official site, hosted by AOL.[82] From the second season to the fourteenth season, the feeds were available through RealNetworks either as a subscription or as a free addition for Gold members.[83] With the fifteenth season onward, the live feeds have aired on the official CBS website, again requiring a subscription from users.[84] Though advertised as being available at any time, the feeds are shut off during the weekly nomination ceremony, Power of Veto ceremony, and the competitions and evictions for that week; this is to provide suspense for the series.[85] Slanderous statements and singing of copyrighted music are also blocked for legal reasons.[86][87][88]

text: CBS is set to be premiering Celebrity Big Brother in the winter of 2018. It will be the first spin-off to air on the broadcast network, and the second season overall to air in the winter television season. The celebrity edition is expected to air in a concentrated run with fewer episodes. However, this edition will air multiple episodes each week and continue to have live feeds and the After Dark companion show as with the main edition.[3]

text: Competitions[edit]

text: Head of Household (HOH)[edit]

text: The Head of Household competition is held at the beginning of each week, and is most often performed on the live eviction episode.[89] Most often, the first Head of Household competition will require HouseGuests to participate either in pairs or in teams.[90] While the fourth, fifth, and eighth seasons had the HouseGuests competing in pairs,[91] the sixth, seventh, eleventh, twelfth, fourteenth, fifteenth, and sixteenth editions all saw HouseGuests competing as part of a group.[92][93] The live Head of Household competitions are typically question based, and will see HouseGuests eliminated each round.[94] Competitions such as "Majority Rules" have been used numerous times, with the game being played in the fourth, fifth, sixth, eighth, tenth, and twelfth seasons;[95][96] a variation of the competition was used in the seventh season.[97] Some competitions will attempt to cause drama in the house, such as the "En Garde" Head of Household competition in which the winner of each round selected the next two to face off against one another.[98] This competition was later used in the tenth, eleventh, twelfth, thirteenth, fourteenth, fifteenth, and sixteenth seasons.[99][100] Various competitions throughout the season will be endurance, requiring HouseGuests to be the last one remaining in the competition.[101] Endurance competitions are often held after game changing announcements, such as when a previously evicted HouseGuest returns.[102] Various endurance competitions may have punished or reward contestants who either fall off first or last.[103] Skill based competitions also appear frequently throughout the season, some of which may last for numerous hours.[104] Skill competitions, such as the thirteenth season's "Big Brother Open", are finished during the live eviction broadcast.[105] The final Head of Household competition of each season features three rounds; the first is endurance, the second is skill, and the final is question based.[106] The record for most Head of Household competitions won in a single season is held by Drew Daniel, Janelle Pierzina, Hayden Moss, Rachel Reilly, Ian Terry, Aaryn Gries, Caleb Reynolds, Vanessa Rousso and Steve Moses in terms of reigns. Frankie Grande won HOH 5 times the sixteenth season, however he was dethroned twice due to the dual HoH twist that was in play during his season, and third reign was rewound due to the rewind button twist. This leaves Frankie with just two full reigns as HoH. Ian Terry has the record for most consecutive Head of Household wins, with four (winning at the Final 9, 7, 5 and 3 rounds) .[107] One of the Head of Household's duties is to nominate 2 people for eviction. Victoria from the sixteenth season holds the record for most times being nominated with nine.

text: Power of Veto (POV)[edit]

text: The Power of Veto is a power first introduced in Big Brother 3.[108] During its first season, it did not allow a nominated HouseGuest to use it on themselves.[109] The final Power of Veto that season was the Golden Power of Veto, and allowed a nominated HouseGuest to remove themself from the block.[110] Following this, the Golden Power of Veto was used in all subsequent seasons.[111][112] The Diamond Power of Veto, used in Big Brother 12 allowed one HouseGuest to remove themselves from the block,[113] as well as choose the replacement nominee only moments before the live eviction.[114] Power of Veto competitions differ drastically from the Head of Household competition, with PoV competitions being more skill based in nature.[115] Competitions such as the "Pop Goes the Veto!" competition, which required HouseGuest to find letter tiles and spell the longest word, have been used in numerous consecutive seasons.[116][117] Competitions such as the "Big Brother Boardwalk" competition see HouseGuests attempting to guess how much of an item there is; this is one of various competitions that do not require HouseGuests to compete in a physical based competition.[118][119] The "How Bad Do You Want It?" Power of Veto competition, first introduced in the seventh season, saw HouseGuests taking punishments in exchange for advancing in the competition.[120] Variations of this competition have been used in numerous subsequent seasons.[121] HouseGuests Janelle Pierzina, Daniele Donato & Paul Abrahamian currently hold the record for most Power of Veto wins in a single season, with five wins each.[122] HouseGuests James Zinkand, Frank Eudy, and Shane Meaney all hold the record for most consecutive Power of Veto wins, with three each.[123]

text: Food and luxury[edit]

text: Food and luxury competitions have been a part of the series since it first premiered. In early seasons, the losers of the food competition would be placed on a peanut butter and jelly diet, and would not be permitted to eat any other foods.[124] Beginning with Big Brother 7, the losers of the Have-Not competition were required to eat "Big Brother Slop" for food, sleep in the Have-Not bedroom, and take cold showers for the week.[125][126][127][128] Slop has proven to be an issue for some HouseGuests; Hypoglycemic HouseGuest Amanda Hansen fainted and had a seizure after only a few days of being on the slop diet,[125] while HouseGuest Allison Nichols had an allergic reaction to the slop (both of these cases occurred in Big Brother 9).[129][130] Both women were medically evacuated from the house, though they returned the following morning.[131] HouseGuests who choose to break the slop rule are punished by Big Brother. HouseGuest Jen Johnson from Big Brother 8 was the first HouseGuest to break the food restriction rules, and earned a penalty eviction vote for doing so; she was ultimately evicted that week.[132][133] Audrey Middleton from Big Brother 17 and Matt Clines from Big Brother 19 also broke the rules and earned a penalty vote and ultimately evicted. HouseGuests Jeff Schroeder and Kevin Campbell of Big Brother 11 also broke the rules, to a lesser degree, and earned an extra day on the slop diet.[134] The HouseGuests also frequently compete in luxury competitions during their time in the house. Most frequently, HouseGuests will compete for the right to watch a film or television show in the house.[135] When competitions for films or television shows occur, an actor or actress from the series may enter the house to host the competition or speak with the HouseGuests. Actors such as Jeremy Piven,[136] David Hasselhoff,[137] and Neil Patrick Harris have all entered the house to participate in luxury competitions or rewards.[138]

text: Battle of the Block[edit]

text: The Battle of the Block was first introduced during Big Brother 16, and was reintroduced during the premiere of Big Brother 17. Instead of the normal singular Head of Household (HOH), two HOHs were named for that week. Each would then nominate a pair of nominees. These two pairs of nominees would compete against each other in a competition. The winning pair was safe from eviction and dethroned the HOH that nominated, allowing for the other HOH to remain in power for the rest of the week. While the winning pair was safe from eviction for the rest of the week, the dethroned HOH was not. There were eight Battle of the Block competitions in season 16 and five in season 17.

text: Battle Back[edit]

text: The Battle Back Competition allows an evicted house guest to return into the house and play as if they had never left. This competition was first introduced in Season 18 and returned to play a role in Season 19 as well.

text: During Season 18, the first two evicted house guests battled one on one, and the winner went on to compete against the third. The winner of that matchup would face the next evicted HouseGuest, and the winner of the final match-up re-entered the game. Victor Arroyo was the winner. Also that season, jury members competed alongside the HouseGuests still in the game. The last HouseGuest standing became the new HoH while the last Jury member standing returned to the game. Victor won this Battle Back making him the first HouseGuest in Big Brother history to reenter the game in the same season for a third time. This version of the Battle Back did not return for season 19.

text: During Season 19, the four evicted house guests played against each other in one competition. The top two then played head-to-head, and the winner then had to face off against a member inside the house. If the evicted house guest won, they would re-enter the game. However, if the non-evicted house guest won, no one would re-enter the game and all four evicted house guests would be permanently eliminated. Cody Nickson beat Paul Abrahamian in the final round and reentered the game.

text: Series details and viewership[edit]

text:
Season
Launch date
Finale date
Days
HouseGuests
Winner
Final Vote
Runner-Up
Average
viewers
(millions)
Episodes

1
July 5, 2000
September 29, 2000
88
10
Eddie McGee
59–27–14%1
Josh Souza
9.10
70

2
July 5, 2001
September 20, 2001
82
12
Will Kirby
5–2
Nicole Schaffrich
7.90
30

3
July 10, 2002
September 25, 2002
Lisa Donahue
9–1
Danielle Reyes
8.70
33

4
July 8, 2003
September 24, 2003
13
Jun Song
6–1
Alison Irwin
8.80
33

5
July 6, 2004
September 21, 2004
14 !142
Drew Daniel
4–3
Michael "Cowboy" Ellis
8.30
31

6
July 7, 2005
September 20, 2005
80
14
Maggie Ausburn
4–3
Ivette Corredro
7.24
30

7
July 6, 2006
September 12, 2006
72
14 !14 (All Returnees)3
Mike "Boogie" Malin
6–1
Erika Landin
7.56
28

8
July 5, 2007
September 18, 2007
81
14
"Evel" Dick Donato
5–2
Daniele Donato
7.52
33

9
February 12, 2008
April 27, 2008
16
Adam Jasinski
6–1
Ryan Quicksall
6.56
33

10
July 13, 2008
September 16, 2008
71
13
Dan Gheesling
7–0
Memphis Garrett
6.72
29

11
July 9, 2009
September 15, 2009
73
13 !13 (1 Returnee)4
Jordan Lloyd
5–25
Natalie Martinez
7.19
30

12
July 8, 2010
September 15, 2010
75
13
Hayden Moss
4–3
Lane Elenburg
7.76
30

13
July 7, 2011
September 14, 2011
14 !14 (6 Returnees)
Rachel Reilly
4–3
Porsche Briggs
7.95
29

14
July 12, 2012
September 19, 2012
16 !16 (4 Returnees)
Ian Terry
6–1
Dan Gheesling
6.79
30

15
June 26, 2013
September 18, 2013
90
16
Andy Herren
7–2
GinaMarie Zimmerman
6.47
36

16
June 25, 2014
September 24, 2014
97
Derrick Levasseur
7–2
Cody Calafiore
6.41
40

17
June 24, 2015
September 23, 2015
98
17 !176
Steve Moses
6–3
Liz Nolan
6.18
40

18
June 22, 2016
September 21, 2016
99
16 (4 Returnees)
Nicole Franzel
5–4
Paul Abrahamian
5.78
42

19
June 28, 2017
September 20, 2017
92
17 (1 Returnee)7
Josh Martinez
5–4
6.06
39

20[4]
Summer 2018
Summer 2018

text:
Season
Launch date
Finale date
Days
HouseGuests
Winner
Final Vote
Runner-Up
Average
viewers
(millions)
Episodes

Over the Top
September 28, 2016
December 1, 2016
65
13 (1 Returnee)8
Morgan Willett
America's Vote1
Jason Roy
N/A
10

Celebrity Big Brother
Winter 2018
2018

text:
^1 For the first season of the main edition and the digital edition, the public voted to determine the winner between the three finalists. However, the voting percentages were not revealed for BBOTT.
^2 Thirteen HouseGuests were originally announced with a set of identical twins secretly playing as one HouseGuest. After surviving the first four evictions, the twins were allowed to compete as individuals.
^3 The 14 returning HouseGuests were chosen among 20 candidates—eight through public vote, and six by the producers.
^4 The returning HouseGuest was chosen among four candidates, determined by a competition.
^5 One of the HouseGuests was expelled from the house during the season. Due to this, their vote was instead decided by the American public.
^6 Sixteen HouseGuests were originally announced with a set of identical twins secretly playing as one HouseGuest. After surviving the first five evictions, the twins were allowed to compete as individuals.
^7 The returning HouseGuest entered the house as a result of an opening night twist.
^8 The returning HouseGuest was chosen among two candidates, determined by public vote. The candidates were from the main edition.

text: Controversy and criticism[edit]

text: Since its inception, Big Brother has been criticized following reports of "HIB" (Harassment, Intimidation, and Bullying),[139] violence in the house, obscene language,[140][141][142][143] breach of integrity,[144][145] and the physical and mental strain of appearing on the series.[146]