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James T. Kirk

James Tiberius Kirk, commonly known as Captain Kirk, is a fictional character in the Star Trek media franchise. Originally played by Canadian actor William Shatner, Kirk first appeared in Star Trek serving aboard the starship USS Enterprise as captain. Kirk leads his crew as they explore new worlds, new civilizations, and "boldly go where no man has gone before". Often, the characters of Spock and Leonard "Bones" McCoy act as his logical and emotional sounding boards, respectively. Kirk has also been portrayed in numerous films, books, comics, webisodes, and video games.

Kirk first appears in the Star Trek episode "The Man Trap", broadcast on September 8, 1966, although the first episode recorded featuring Shatner was "Where No Man Has Gone Before". Shatner continued in the role for the show's three seasons, and later provided the voice of the animated version of Kirk in Star Trek: The Animated Series (1973–1974). Shatner returned to the role for Star Trek: The Motion Picture (1979) and in six subsequent films.

American actor Chris Pine portrays an alternative young version of the character in the 2009 Star Trek film. Pine reprised his role in Star Trek Into Darkness (2013) and in Star Trek Beyond (2016). Paul Wesley portrays Kirk on the Paramount+ series Star Trek: Strange New Worlds, set prior to Kirk's captaincy of the Enterprise. Other actors have played the character in fan-created media, and the character has been the subject of multiple spoofs and satires.

Biography
James Tiberius Kirk was born in Riverside, Iowa, on March 22, 2233, where he was raised by his parents, George and Winona Kirk. Although born on Earth, Kirk lived for a time on Tarsus IV, where he was one of nine surviving witnesses to the massacre of 4,000 colonists by Kodos the Executioner. James Kirk's brother, George Samuel Kirk, is first mentioned in "What Are Little Girls Made Of?" and introduced and killed in "Operation -- Annihilate!", leaving behind three children.

Kirk became the first and only student at Starfleet Academy to defeat the Kobayashi Maru test, garnering a commendation for original thinking after he reprogrammed the computer to make the "no-win scenario" winnable. Kirk was granted a field commission as an ensign and posted to advanced training aboard the USS Republic. He was then promoted to lieutenant junior grade and returned to Starfleet Academy as a student instructor. According to a friend, students could either "think or sink" in his class, and Kirk himself was "a stack of books with legs". Upon graduating in the top five percent, Kirk was promoted to lieutenant and served aboard the USS Farragut. While assigned to the Farragut, Kirk commanded his first planetary survey and survived a deadly attack by a bizarre cloud-like creature that killed a large portion of the Farragut's crew, including his commanding officer, Captain Garrovick. Although the surviving Executive Officer disagreed, Kirk blamed himself for years for hesitating to fire his assigned weapons upon seeing the threat until a later encounter with the creature showed that firing immediately with conventional weapons would have been useless anyway. Kirk became Starfleet's youngest starship captain after receiving command of the USS Enterprise (NCC-1701) for a five-year mission, three years of which are depicted in the original Star Trek series. Kirk's most significant relationships in the television series are with first officer Spock and chief medical officer Dr. Leonard "Bones" McCoy. McCoy is someone to whom Kirk unburdens himself and is a foil to Spock. Robert Jewett and John Shelton Lawrence's The Myth of the American Superhero describes Kirk as "a hard-driving leader who pushes himself and his crew beyond human limits". Terry J. Erdman and Paula M. Block, in their Star Trek 101 primer, note that while "cunning, courageous and confident", Kirk also has a "tendency to ignore Starfleet regulations when he feels the end justifies the means"; he is "the quintessential officer, a man among men and a hero for the ages". Although Kirk throughout the series becomes romantically involved with various women, when confronted with a choice between a woman and the Enterprise, "his ship always won".

Roddenberry wrote in a production memo that Kirk is not afraid of being fallible, but rather is afraid of the consequences to his ship and crew should he make an error in judgment. Roddenberry wrote:

"[Kirk] has any normal man's insecurities and doubts, but he knows he cannot ever show them—except occasionally in private with ship's surgeon McCoy or in subsequent moments with Mr. Spock whose opinions Kirk has learned to value so highly."

In Star Trek: The Motion Picture, Admiral Kirk is Chief of Starfleet Operations, and he takes command of the Enterprise from Captain Willard Decker. Star Trek creator Gene Roddenberry's novelization of The Motion Picture depicts Kirk married to a Starfleet officer killed during a transporter accident. At the beginning of Star Trek II: The Wrath of Khan, Kirk takes command of the Enterprise from Captain Spock to pursue his enemy from "Space Seed", Khan Noonien Singh. The movie introduces Kirk's former lover Carol and his son, David Marcus. Spock, who notes that "commanding a starship is [Kirk's] first, best destiny", dies at the end of Star Trek II. In Star Trek III: The Search for Spock, Admiral Kirk leads his surviving officers in a successful mission to rescue Spock from a planet on which he is reborn. Although Kirk is demoted to Captain in Star Trek IV: The Voyage Home for disobeying Starfleet orders, he also receives command of a new Enterprise, the USS Enterprise-A (NCC 1701-A). The ship is ordered decommissioned at the end of Star Trek VI: The Undiscovered Country.

In Star Trek Generations, Captain Jean-Luc Picard finds Kirk living in the timeless Nexus, despite the fact that history recorded his death during the Enterprise-B's maiden voyage, Kirk having fallen into the Nexus in the incident that caused his "death". Picard persuades Kirk to return to Picard's present to help stop the villain Soran from destroying Veridian III's sun. Although Kirk initially refuses the offer, he agrees after realizing the Nexus cannot give him the one thing he has always sought: the ability to make a difference. The two leave the Nexus and stop Soran. However, Kirk is mortally wounded; as he dies, Picard assures him that he helped to "make a difference". Picard buries Kirk on the planet, however in Star Trek: Picard 's third season (2023), Kirk’s body is revealed to be stored in stasis at the Daystrom Institute by Section 31.

Shatnerverse
Shatner has since written a series of novels featuring Kirk being brought back to life by a Borg-Romulan alliance to serve as an assassin against Picard, but he is restored to normal and returns to provisional active service in Starfleet, including opposing his Mirror Universe counterpart.

Kelvin Timeline
In this series, Chris Pine plays Kirk, Zachary Quinto plays Spock, Karl Urban plays "Bones" McCoy, Simon Pegg plays Montgomery "Scotty" Scott, Zoë Saldana plays Nyota Uhura, John Cho plays Hikaru Sulu, and Anton Yelchin plays Pavel Chekov.

The series takes place in an alternate course of events known as the "Kelvin Timeline" that reveal different origins for Kirk, the formation of his association with Spock, and how they came to serve together on the Enterprise. Whereas The Original Series portrayed Kirk as having been born in Iowa, the Star Trek film portrays him being born on a shuttle escaping the starship USS Kelvin in an alternate timeline in which his father is killed when the Kelvin is attacked by a Romulan ship from the future. In the film, George and Winona Kirk name their son James Tiberius after his maternal and paternal grandfathers, respectively.

Although the film treats specific details from Star Trek as mutable, characterizations are meant to "remain the same" though with Kirk being initially portrayed as "a reckless, bar-fighting rebel" but who eventually matures. According to Pine, the character is "a 25-year-old [who acts like a] 15-year-old" and who is "angry at the world", until he enrolls in Starfleet Academy basically after being 'dared' by Captain Christopher Pike.

Kirk and Spock clash at Starfleet Academy, but, over the course of the film, Kirk focuses his "passion and obstinance and the spectrum of emotions" and becomes captain of the Enterprise. He is also aided by a meeting with the time-displaced Spock of the original timeline, who inspires Kirk to live up to his full potential after learning about the parallel version of himself and his accomplishments as Captain in the elder Spock's timeline.

Conception and television
Jeffrey Hunter played the commanding officer of the USS Enterprise, Captain Christopher Pike, in the rejected Star Trek television pilot "The Cage". In developing a new pilot episode, called "Where No Man Has Gone Before", series creator Gene Roddenberry changed the captain's name to "James Kirk" after rejecting other options like Hannibal, Timber, Flagg and Raintree. The episode title may have been inspired by Captain James Cook, whose journal entry "ambition leads me ... farther than any other man has been before me" inspired the episode title, and became the series catch-phrase in the opening voice-over. The character is in part based on C. S. Forester's Horatio Hornblower hero, and NBC wanted the show to emphasize the captain's "rugged individualism". Roddenberry had previously used the middle name of Tiberius for the leading character in his earlier television series, The Lieutenant, which was to feature several actors who would later go on to be part of the production of Star Trek.

Jack Lord was Desilu Productions' original choice to play Kirk, but his demand for fifty-percent ownership of the show led to him not being hired. The second pilot episode was successful, and "Where No Man Has Gone Before" was broadcast as the third episode of Star Trek on September 22, 1966.

William Shatner tried to imbue the character with qualities of "awe and wonder" absent from "The Cage". He also drew upon his experiences as a Shakespearean actor to invigorate the character, whose dialogue at times is laden with jargon. Not only did Shatner take inspiration from Roddenberry's suggestion of Hornblower, but also from Alexander the Great – "the athlete and the intellectual of his time" – whom Shatner had played for an unsold television pilot two years earlier. In addition, the actor based Kirk partly on himself because "the fatigue factor [after weeks of daily filming] is such that you try to be as honest about yourself as possible". A comedy veteran, Shatner suggested making the show's characters as comfortable working in space as they would be at sea, thus having Kirk be a humorous "good-pal-the-captain, who in time of need would snap to and become the warrior". Changing the character to be "a man with very human emotions" also allowed for the development of the Spock character. Shatner wrote that "Kirk was a man who marveled and greatly appreciated the endless surprises presented to him by the universe ... He didn't take things for granted and, more than anything else, respected life in every one of its weird weekly adventure forms".

Films
Shatner did not expect Star Trek to be successful, so when it was cancelled in 1969, he assumed it would be the end of his association with the franchise. Following Star Trek's popularity after its cancelation, Shatner went on to voice Kirk in the animated Star Trek series, star in the first seven Star Trek films, and provide voice acting for several games. Star Trek II: The Wrath of Khan director and writer Nicholas Meyer, who had never seen an episode of Star Trek before he was assigned to direct, conceived a "Hornblower in outer space" atmosphere, unaware that those books had been an influence on the show. Meyer also emphasized parallels to Sherlock Holmes, in that both characters waste away in the absence of stimuli: new cases for Holmes; starship adventures for Kirk.

Meyer's The Wrath of Khan script focuses on Kirk's age, with McCoy giving him a pair of glasses as a birthday present. The script states that Kirk is 49, but Shatner was unsure about being specific about Kirk's age because he was hesitant to portray a middle-aged version of himself. Shatner changed his mind when producer Harve Bennett convinced Shatner that he could age gracefully like Spencer Tracy. Spock's sacrifice at the end of the film allows for Kirk's spiritual rebirth; after commenting earlier that he feels old and worn out, Kirk states in the final scene that he feels "young." Additionally, Spock's self-sacrificing solution to the no-win Kobayashi Maru scenario, which Kirk had cheated his way through, forces Kirk to confront death and to grow as a character.

Both Shatner and test audiences were dissatisfied that Kirk was fatally shot in the back in the original ending of the film Star Trek Generations. An addendum inserted while Shatner's Star Trek Movie Memories memoir was being printed expresses his enthusiasm at being called back to film a rewritten ending. Despite the rewrite, Generations co-writer Ronald D. Moore said that Kirk's death, which was intended to "resonate throughout the Star Trek franchise", failed to "pay off the themes [of death and mortality] in the way we wanted". Malcolm McDowell, whose character kills Kirk, was dissatisfied with both versions of Kirk's death: he believed Kirk should have been killed "in a big way". McDowell claims to have received death threats after Generations was released.

Franchise "reboot"
In Star Trek (2009), screenwriters Alex Kurtzman and Roberto Orci focused their story on Kirk and Spock in the movie's alternative timeline while attempting to preserve key character traits from the previous depictions. Kurtzman said casting someone whose portrayal of Kirk would show that the character "is being honored and protected" was "tricky", but that the "spirit of Kirk is very much alive and well" in Pine's depiction. Due to his belief that he could not take himself seriously as a leader, Pine recalled having difficulty with his audition, which required him "to bark 'Trek jargon'", but his charisma impressed director J. J. Abrams. Pine's chemistry with Zachary Quinto, playing Spock, led Abrams to offer Pine the role. Jimmy Bennett played Kirk in scenes depicting the character's childhood. The writers turned to material from the novel Best Destiny for inspiration as to Kirk's childhood.

In preparing to play Kirk, Pine decided to embrace the character's key traits – "charming, funny, leader of men" – rather than try to fit the "predigested image" of Shatner's portrayal. Pine specifically did not try to mirror Shatner's cadence, believing that doing so would become "an impersonation". Pine said he wanted his portrayal of Kirk to most resemble Harrison Ford's Indiana Jones or Han Solo characters, highlighting their humor and "accidental hero" traits.

A misunderstanding arose during the film's production about the possibility of Shatner making a cameo appearance. According to Abrams, the production team considered ways to resurrect Shatner's deceased Kirk character, but could not devise a way that was not "lame". However, Abrams believed Shatner misinterpreted language about trying to get "him" into the movie as a reference to Shatner, and not his character. Shatner released a YouTube video expressing disappointment at not being approached for a cameo. Although Shatner questioned the wisdom of not including him in the film, he predicted the movie would be "wonderful" and that he was "kidding" about Abrams not offering him a cameo.

Star Trek: Strange New Worlds
Kirk also appears in Star Trek: Strange New Worlds, which is set six years before the events of the original series. He first appears in the final episode of Season 1, portrayed by Paul Wesley, and appeared as a recurring guest in Season 2. In this series, the Enterprise has another captain, Kirk's predecessor Christopher Pike, who first appeared in "The Cage". Other fellow crew characters from the original series, such as Uhura, Spock and Nurse Chapel are main characters in Strange New Worlds.

Reception
According to Shatner, early Star Trek reviewers described his performance as "wooden", with most of the show's acting praise and media interest going to Nimoy. However, Shatner's mannerisms when portraying Kirk have become "instantly recognizable" and Shatner won a Saturn Award for Best Actor in 1982 for The Wrath of Khan. Star Trek II director Nicholas Meyer said Shatner "gives the best performance of his life" in The Wrath of Khan. The Guardian called Pine's performance of Kirk an "unqualified success", and The Boston Globe said Pine is "a fine, brash boy Kirk". Slate, which called Pine "a jewel", described his performance as "channel[ing]" Shatner without being an impersonation.

Slate described Shatner's depiction of Kirk as an "expansive, randy, faintly ridiculous, and yet supremely capable leader of men, Falstaffian in his love of life and largeness of spirit". The Myth of the American Superhero refers to Kirk as a "superhuman redeemer" who "like a true superhero ... regularly escapes after risking battle with monsters or enemy spaceships". Although some episodes question Kirk's position as a hero, Star Trek "never left the viewer in doubt for long". Others have commented that Kirk's exaggerated "strength, intelligence, charm, and adventurousness" make him unrealistic. Kirk is described as able to find ways "through unanticipated problems to reach [his] goals" and his leadership style is most "appropriate in a tight, geographically identical team with a culture of strong leadership." Although Roddenberry conceived the character as being "in a very real sense ... 'married' " to the Enterprise, Kirk has been noted for "his sexual exploits with gorgeous females of every size, shape and type"; he has been called "promiscuous" and labeled a "womanizer". The Last Lecture author Randy Pausch believed he became a better teacher, colleague, and husband because he watched Kirk run the Enterprise; Pausch wrote that "for ambitious boys with a scientific bent, there could be no greater role model than James T. Kirk". David A. Goodman commented that Kirk "has as much reality as possible for a fictional character."

In 2012, IGN ranked the character Captain Kirk, as depicted in the original series, films, and the new Kirk in 2009 film Star Trek, as the number one top character of the Star Trek universe. In 2016, Kirk was ranked as the #1 most important character of Starfleet within the Star Trek science fiction universe by Wired magazine, out of 100 characters of the franchise.

In 2018, CBR ranked Kirk the best Starfleet character of Star Trek, including later television series.

In July 2019, Screen Rant ranked Kirk the 8th smartest character of Star Trek.

Cultural impact
In 1985, Riverside, Iowa petitioned Roddenberry and Paramount Pictures for permission to "adopt" Kirk as their town's "Future Son". Shatner and Roddenberry approved the proposal. Paramount wanted $40,000 for a license to reproduce a bust of Kirk, but the city instead set a plaque and built a replica of the Enterprise (named the "USS Riverside"), and the Riverside Area Community Club holds an annual "Trek Fest" in anticipation of Kirk's birthday.

Kirk has been the subject of a wide range of television spoofs that aired in many countries, including The Carol Burnett Show and KI.KA's Bernd das Brot. John Belushi's impression of Kirk for Saturday Night Live, which he described as his favorite role, was "dead-on". Jim Carrey has been praised for his satire of the character in a 1992 episode of In Living Color. Comedian Kevin Pollak is well known for his impressions of Shatner as Kirk.

Kirk's memorable scream of "Khan!" in the 1982 movie Star Trek II: The Wrath of Khan has become a pop culture icon in its own right, spawning internet memes and is widely parodied and paid tribute to.

Kirk has been referenced in the lyrics of many pop songs. Early examples include the 1979 song "Where's Captain Kirk?" by Spizzenergi, the 1982 rap song "Tough" by Kurtis Blow, and 1983's "99 Luftballons" by Nena (both German and English versions). More recently, in the 2003 remix of 1998’s "That Don't Impress Me Much", Shania Twain puts forth Captain Kirk as one of the unattainable ideals to whom her unappealingly haughty suitor apparently thinks himself equal.

Kirk has been merchandised in a variety of ways, including collectible busts, action figures, mugs, t-shirts, and Christmas tree ornaments. A Kirk Halloween mask was altered and used as the mask worn by the character Michael Myers in the Halloween film franchise. In 2002, Kirk's captain's chair from the original Star Trek was auctioned for $304,000.

In a 2010 Space Foundation survey, Kirk tied with cosmonaut Yuri Gagarin as the No. 6 most popular space hero.

Captain Kirk has also been portrayed in feline form. First, anthropomorphically, in two episodes of the 1975 Filmation Saturday morning animated children’s  series The Secret Lives of Waldo Kitty. The cartoon is based around the title character’s fantasies about being various heroic felines based on popular culture icons. Later came scientific illustrator Jenny Parks' 2017 book Star Trek Cats, in which Kirk is depicted as an orange tabby cat.

The Kirk crater on Pluto's moon, Charon, is named after the character.

Fan productions
In addition to television, feature films, books, and parodies, Kirk has also been portrayed in non-canon fan fiction.

Star Trek: New Voyages
The Star Trek: New Voyages fan production, known from 2008 until 2015 as Star Trek: Phase II, portrays the further voyages of the original Enterprise crew. The series' creators feel that "Kirk, Spock, McCoy and the rest should be treated as 'classic' characters like Willy Loman from Death of a Salesman, Gandalf from The Lord of the Rings or even Hamlet, Othello or Romeo. Many actors have and can play the roles, each offering a different interpretation of said character."

James Cawley played Kirk in most of the ten episode Phase II series from its beginning in 2004 before replacing himself with actor Brian Gross. Wired observes that while Cawley's depiction "lacks Shatner's vulnerability", the actor has enough swagger "to be passable in the role". Cawley's portrayal was well-known enough at Paramount that a group of Star Trek: Enterprise writers called for Cawley's attention at a science fiction convention by shouting "Hey, Kirk!" at him while Shatner sat nearby.

Star Trek Continues
First produced in 2013, the 11 episode series Star Trek Continues also looked to chronicle the "lost seasons" of Star Trek: The Original Series. The series developer and producer is anime voice actor Vic Mignogna, who also plays the role of Kirk. Rounding out the core cast is fellow voice actor Todd Haberkorn as Spock, Chris Doohan (son of the original Scotty actor James Doohan) as Scotty, and as McCoy first author-producer Larry Nemecek, followed by voice actor Chuck Huber. It also co-starred Grant Imahara (MythBusters) as Sulu.

The first episode, "Pilgrim of Eternity" (with Michael Forest reprising his role as Apollo from the original series episode "Who Mourns for Adonais?") was released in 2013. The second episode, "Lolani" (featuring guest star Lou Ferrigno), was released in February 2014, and a third episode, "Fairest of Them All" was released in June 2014 and won a Burbank International Film Festival award for "Best New Media – Drama". Star Trek Continues also won a Geekie Award for "Best Web Series". On June 19, 2015, Episode 4 of the series was posted and titled "White Iris". All eleven full episodes have been released as of December, 2017.

Legacy
In October 2021, Kirk's actor from The Original Series William Shatner flew to space aboard a Blue Origin sub-orbital capsule. At age 90, he became the oldest person to fly to space and one of the first 600 to do so.

title: James T. Kirk


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Mesosphere

The mesosphere is the third layer of the atmosphere, directly above the stratosphere and directly below the thermosphere. In the mesosphere, temperature decreases as altitude increases. This characteristic is used to define limits: it begins at the top of the stratosphere (sometimes called the stratopause), and ends at the mesopause, which is the coldest part of Earth's atmosphere, with temperatures below -143 C. The exact upper and lower boundaries of the mesosphere vary with latitude and with season (higher in winter and at the tropics, lower in summer and at the poles), but the lower boundary is usually located at altitudes from 47 to 51 km above sea level, and the upper boundary (the mesopause) is usually from 85 to 100 km.

The stratosphere and mesosphere are sometimes collectively referred to as the "middle atmosphere", which spans altitudes approximately between 12 and 80 km above Earth's surface. The mesopause, at an altitude of 80 –, separates the mesosphere from the thermosphere—the second-outermost layer of Earth's atmosphere. On Earth, the mesopause nearly co-incides with the turbopause, below which different chemical species are well-mixed due to turbulent eddies. Above this level the atmosphere becomes non-uniform because the scale heights of different chemical species differ according to their molecular masses.

The term near space is also sometimes used to refer to altitudes within the mesosphere. This term does not have a technical definition, but typically refers to the region roughly between the Armstrong limit (about 62,000 ft or 19 km, above which humans require a pressure suit in order to survive) and the Kármán line (where astrodynamics must take over from aerodynamics in order to achieve flight); or, by another definition, to the space between the highest altitude commercial airliners fly at (about 40,000 ft (12.2 km)) and the lowest perigee of satellites being able to orbit the Earth (about 45 mi (73 km)). Some sources distinguish between the terms "near space" and "upper atmosphere", so that only the layers closest to the Kármán line are described as "near space".

Temperature
Within the mesosphere, temperature decreases with increasing height. This is a result of decreasing absorption of solar radiation by the rarefied atmosphere having a diminishing relative ozone concentration as altitude increases (ozone being the main absorber in the UV wavelengths that survived absorption by the thermosphere). Additionally, this is also a result of increasing cooling by CO2 radiative emission. The top of the mesosphere, called the mesopause, is the coldest part of Earth's atmosphere. Temperatures in the upper mesosphere fall as low as about -100 C, varying according to latitude and season.

Dynamic features
The main most important features in this region are strong zonal (East-West) winds, atmospheric tides, internal atmospheric gravity waves (commonly called "gravity waves"), and planetary waves. Most of these tides and waves start in the troposphere and lower stratosphere, and propagate to the mesosphere. In the mesosphere, gravity-wave amplitudes can become so large that the waves become unstable and dissipate. This dissipation deposits momentum into the mesosphere and largely drives global circulation.

Noctilucent clouds are located in the mesosphere. The upper mesosphere is also the region of the ionosphere known as the D layer, which is only present during the day when some ionization occurs with nitric oxide being ionized by Lyman series-alpha hydrogen radiation. The ionization is so weak that when night falls, and the source of ionization is removed, the free electron and ion form back into a neutral molecule.

A 5 km deep sodium layer is located between 80 - 105 km. Made of unbound, non-ionized atoms of sodium, the sodium layer radiates weakly to contribute to the airglow. The sodium has an average concentration of 400,000 atoms per cubic centimetre. This band is regularly replenished by sodium sublimating from incoming meteors. Astronomers have begun utilizing this sodium band to create "guide stars" as part of the adaptive optical correction process used to produce ultra-sharp ground-based observations. Other metal layers, e.g. iron and potassium, exist in the upper mesosphere/lower thermosphere region as well.

Beginning in October 2018, a distinct type of aurora has been identified, originating in the mesosphere. Often referred to as 'dunes' due to their resemblance to sandy ripples on a beach, the green undulating lights extend toward the equator. They have been identified as originating about 96 km above the surface. Since auroras are caused by ultra-high-speed solar particles interacting with atmospheric molecules, the green color of these dunes has tentatively been explained by the interaction of those solar particles with oxygen molecules. The dunes therefore occur where mesospheric oxygen is more concentrated.

Millions of meteors enter the Earth's atmosphere, averaging 40,000 tons per year. The ablated material, called meteoric smoke, is thought to serve as condensation nuclei for noctilucent clouds.

Exploration
The mesosphere lies above altitude records for aircraft, while only the lowest few kilometers are accessible to balloons, for which the altitude record is 53.0 km. Meanwhile, the mesosphere is below the minimum altitude for orbital spacecraft due to high atmospheric drag. It has only been accessed through the use of sounding rockets, which are only capable of taking mesospheric measurements for a few minutes per mission. As a result, it is the least-understood part of the atmosphere, resulting in the humorous moniker ignorosphere. The presence of red sprites and blue jets (electrical discharges or lightning within the lower mesosphere), noctilucent clouds, and density shears within this poorly understood layer are of current scientific interest.

On February 1, 2003, broke up on reentry at about 62 km altitude, in the lower mesosphere, killing all seven crew members.

Phenomena in mesosphere and near space

 * Airglow
 * Atmospheric tides
 * Ionosphere
 * Meteors
 * Noctilucent clouds
 * Polar aurora
 * Sprite (lightning)
 * Upper atmospheric lightning (Transient luminous event)

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Mesosphere


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User:Karen Johnson

October 2004
It's been a long time between drinks... I recently got involved with the Distributed Proofreaders project, and somebody there had a link back to here and I clicked on it out of curiosity, only to find that I had messages, and that the photo policy had changed so my images needed reattribution. So I'm back to try and track them down and add it. If you see any image that says it was taken by Karen Johnson or Greg Johnson, please add the licence to the page - this means you are free to reproduce it or to alter it for noncommercial purposes, as long as I (or Greg) get credit as the original photographer. BTW, the new skin for the wikipedia looks fantastic! KJ 08:25, Oct 2, 2004 (UTC)

March/April 2004
I'm here but you won't see me... my primary task at the moment is copying relevant parts of the fruit and vegetable entries over to the wikibooks cookbook, and extending them in the culinary direction. I'm about up to vegies that aren't actually articles here yet, so you may see more contributions from me as I even the score.

February 2004
Somebody told me that things were improving around here and so I came back to look. I'm impressed, especially by the twenty new servers! It's great to see that my predictions of last year were entirely wrong, because the Wikipedia project has become an all-encompassing empire! Well done everyone who's made it happen. I'm trying to spend more time on reallife crafting projects (I started scrapbooking and card-making...) and less time online, but I'll be around every now and then... Now I'll have to try and remember my wiki-code - I've forgotten it ALL :( KJ 10:00, 15 Feb 2004 (UTC)

August 2003'
Sigh... I thought that the performance bugs would have been fixed or at least worked around by now. But I see that there is not even a basic search function activated, which makes the wikipedia to all intents and purposes utterly unusable. An encyclopedia is USELESS without an index. As I said way back in April, at which point improvements were promised, this project is collapsing under its own weight. It makes me very sad to see it because I thought it was such a Good Thing to be participating in. I have several thousand photos from my US/Canada trip that I was going to add to relevant places, but without an index I can't even find the relevant articles so they'll have to stay unpublished. I'll come back in a few weeks and see if things are looking any brighter... until then, goodbye! KJ 03:43, 6 Aug 2003 (UTC)

21 June 2003
Hi honey, I'm home... I'm far too jetlagged to try to do any contributing as yet but I'll be getting back to things soon - it doesn't even feel as if I went anywhere! KJ 09:04 21 Jun 2003 (UTC)

April 2003
I am temporarily withdrawing from this project because it has obviously failed in fundamental respects. If the database is not even searchable, then there is no point in having it at all. You CAN'T have a hundred-thousand page book without an index and expect people to use an outside index to find information in it... I'll be back from America at the end of June and hopefully matters will have improved considerably by then, so that the wikipedia will be properly usable. KJ 01:14 Apr 4, 2003 (UTC)

March 2003
Busy busy busy!!!!!!!! I'm off to the US of A and Canada in three weeks time, and I won't be back (or have net access) until the end of June 2003. This is my first overseas trip, and I'm looking forward to it! See you all much later :) KJ 11:45 Mar 21, 2003 (UTC)

December 7, 2002
I'm back! This is the first moment I've had to open the wikipedia since I got home... Canberra was surprisingly interesting, and I took lots of rolls of film and will hopefully be able to scan in some pics of my nation's capital for the wikipedia once they're developed...

November 26th 2002
I'm off again. Canberra this time. I'll be back next week...

About Me
I'm an Australian 33yo woman and I've always been interested in writing and information. I'm on disability, so I have plenty of time to kill and I spend a lot of time at my computer. My primary interests are writing and desktop publishing, papercrafts (cardmaking and scrapbooking), photography, and cooking. I love nature, travel (when I'm able to afford it!), and my country. My latest enthusiasms are digital scrapbooking, and the Distributed Proofreaders project.

Photography
NOTE - all images by me are licenced under the following Creative Commons license.

I was quite a keen photographer in the past, but I have boxes and boxes of photos of Australian plants, animals and scenery in my cupboard and I'm going through some of them and finding illustrations suitable for wikipedia articles. These are the articles I have illustrated with my own images thusfar:
 * banksia; black swan; blossom; boulder; correa; daffodil, eagle; emu; fairy penguin; fig; fur seal; hydrangea; Jack Russell terrier; koala; Melbourne; nectarine, otter; peahen; pelican; pentomino; pink heath; rhododendron; Red-necked Wallaby; wandering jew; wattle

Writing
Articles I have contributed substantial content to [usually by starting from scratch or adding to a stub article] Because I've started them from scratch they still need a lot of work, so if you have any information to add please do! Note - this list is a very old one... I stopped keeping track of substantial contributions and new articles after the first 500 or so. But it does give you a general overview of my areas of interest, so I'm keeping it for posterity.

Books and Writing

 * David Eddings; James White; Lawrence Durrell; Marion Zimmer Bradley; Mercedes Lackey; Steven Brust; Susan Cooper; The Belgariad; The Malloreon

Arts and Crafts

 * Arts and Crafts; cotton; cotton gin; embroidery; origami; sampler (needlework); pottery; textile;

Australiana

 * eucalyptus; tree fern;
 * ANZAC Day;
 * Play School; Sesame Street; Young Talent Time; Skippy the bush kangaroo; Judith Durham; The Seekers
 * National Parks (Tasmania, Australia); Dandenong Ranges National Park; Australian cuisine
 * Australian native animals; Australian native plants;

Health Issues

 * allergen; allergy; cyclothymia; dysthymia; ectopic pregnancy; emphysema; insomnia; MCS; melanin; menopause; Mental illness; mole (skin marking); MSG;panic attack; PCOS; pelvic ultrasound; pneumonia; psychosomatic illness; rabies; Seasonal Affective Disorder; social phobia;

Cooking/Food

 * cake; cardamom; cashew; citrus; custard; egg; enchilada; fructose; fruitmince; ice cream; Lime; milk bar; MSG; pastry; sago; sauce; soy sauce; sugar beet; tapioca; trifle;

Animals

 * Bengal cat; bicolor cat; black swan; butterfly; cat breeds; caterpillar; Difference between a butterfly and a moth; frog; koala; lyrebird; moggy; persian cat; ragdoll cat; show cat; Siamese cat; sparrow; swallow; swift; tabby cat

Other

 * Backstreet Boys; blossom; cornett; Demosthenes; detonator; Eddie Murphy; Great red spot; plum; Robin Williams; sailing ship; schooner; seed; sloop;

Contact Me
If you would like to see more of my [other] work, visit my homepage http://www.kajikitscorner.com to see a wide assortment of my stuff.

If you want to talk to me or ask me something, please leave any comments/queries on my talk page - http://www.wikipedia.com/wiki/User_talk:Karen_Johnson otherwise known as User talk:Karen Johnson

Or alternatively you are welcome to email me at kajikit@gmail.com My inbox is always open.

Karen Johnson, last modified Saturday 2 October 2004

title: User:Karen Johnson


text:
Thermosphere

The thermosphere is the layer in the Earth's atmosphere directly above the mesosphere and below the exosphere. Within this layer of the atmosphere, ultraviolet radiation causes photoionization/photodissociation of molecules, creating ions; the thermosphere thus constitutes the larger part of the ionosphere. Taking its name from the Greek θερμός (pronounced thermos) meaning heat, the thermosphere begins at about 80 km (50 mi) above sea level. At these high altitudes, the residual atmospheric gases sort into strata according to molecular mass (see turbosphere). Thermospheric temperatures increase with altitude due to absorption of highly energetic solar radiation. Temperatures are highly dependent on solar activity, and can rise to 2000 C or more. Radiation causes the atmospheric particles in this layer to become electrically charged, enabling radio waves to be refracted and thus be received beyond the horizon. In the exosphere, beginning at about 600 km (375 mi) above sea level, the atmosphere turns into space, although, by the judging criteria set for the definition of the Kármán line (100 km), most of the thermosphere is part of space. The border between the thermosphere and exosphere is known as the thermopause.

The highly attenuated gas in this layer can reach 2500 C. Despite the high temperature, an observer or object will experience low temperatures in the thermosphere, because the extremely low density of the gas (practically a hard vacuum) is insufficient for the molecules to conduct heat. A normal thermometer will read significantly below 0 C, at least at night, because the energy lost by thermal radiation would exceed the energy acquired from the atmospheric gas by direct contact. In the anacoustic zone above 160 km, the density is so low that molecular interactions are too infrequent to permit the transmission of sound. The dynamics of the thermosphere are dominated by atmospheric tides, which are driven predominantly by diurnal heating. Atmospheric waves dissipate above this level because of collisions between the neutral gas and the ionospheric plasma.

The thermosphere is uninhabited with the exception of the International Space Station, which orbits the Earth within the middle of the thermosphere between 408 and 410 km and the Tiangong space station, which orbits between 340 and 450 km.

Neutral gas constituents
It is convenient to separate the atmospheric regions  according to the two temperature minima at an altitude of about 12 km (the tropopause) and at about 85 km (the mesopause) (Figure 1). The thermosphere (or the upper atmosphere) is the height region above 85 km, while the region between the tropopause and the mesopause is the middle atmosphere (stratosphere and mesosphere) where absorption of solar UV radiation generates the temperature maximum near an altitude of 45 km and causes the ozone layer.

The density of the Earth's atmosphere decreases nearly exponentially with altitude. The total mass of the atmosphere is M = ρA H  ≃ 1 kg/cm2 within a column of one square centimeter above the ground (with ρA = 1.29 kg/m3 the atmospheric density on the ground at z = 0 m altitude, and H ≃ 8 km the average atmospheric scale height). Eighty percent of that mass is concentrated within the troposphere. The mass of the thermosphere above about 85 km is only 0.002% of the total mass. Therefore, no significant energetic feedback from the thermosphere to the lower atmospheric regions can be expected.

Turbulence causes the air within the lower atmospheric regions below the turbopause at about 90 km to be a mixture of gases that does not change its composition. Its mean molecular weight is 29 g/mol with molecular oxygen (O2) and nitrogen (N2) as the two dominant constituents. Above the turbopause, however, diffusive separation of the various constituents is significant, so that each constituent follows its barometric height structure with a scale height inversely proportional to its molecular weight. The lighter constituents atomic oxygen (O), helium (He), and hydrogen (H) successively dominate above an altitude of about 200 km and vary with geographic location, time, and solar activity. The ratio N2/O which is a measure of the electron density at the ionospheric F region is highly affected by these variations. These changes follow from the diffusion of the minor constituents through the major gas component during dynamic processes.

The thermosphere contains an appreciable concentration of elemental sodium located in a 10 km thick band that occurs at the edge of the mesosphere, 80 to 100 km above Earth's surface. The sodium has an average concentration of 400,000 atoms per cubic centimeter. This band is regularly replenished by sodium sublimating from incoming meteors. Astronomers have begun using this sodium band to create "guide stars" as part of the optical correction process in producing ultra-sharp ground-based observations.

Energy budget
The thermospheric temperature can be determined from density observations as well as from direct satellite measurements. The temperature vs. altitude z in Fig. 1 can be simulated by the so-called Bates profile:

(1) $$T = T_\infty - (T_\infty- T_0) e^{ -s(z - z_0)}$$

with T∞ the exospheric temperature above about 400 km altitude, To = 355 K, and zo = 120 km reference temperature and height, and s an empirical parameter depending on T∞ and decreasing with T∞. That formula is derived from a simple equation of heat conduction. One estimates a total heat input of qo≃ 0.8 to 1.6 mW/m2 above zo = 120 km altitude. In order to obtain equilibrium conditions, that heat input qo above zo is lost to the lower atmospheric regions by heat conduction.

The exospheric temperature T∞ is a fair measurement of the solar XUV radiation. Since solar radio emission F at 10.7 cm wavelength is a good indicator of solar activity, one can apply the empirical formula for quiet magnetospheric conditions.

(2) $$T_\infty \simeq 500 + 3.4 F_0$$

with T∞ in K, Fo in 10−2 W m−2 Hz−1 (the Covington index) a value of F averaged over several solar cycles. The Covington index varies typically between 70 and 250 during a solar cycle, and never drops below about 50. Thus, T∞ varies between about 740 and 1350 K. During very quiet magnetospheric conditions, the still continuously flowing magnetospheric energy input contributes by about 250 K to the residual temperature of 500  K in eq.(2). The rest of 250 K in eq.(2) can be attributed to atmospheric waves generated within the troposphere and dissipated within the lower thermosphere.

Solar XUV radiation
The solar X-ray and extreme ultraviolet radiation (XUV) at wavelengths < 170 nm is almost completely absorbed within the thermosphere. This radiation causes the various ionospheric layers as well as a temperature increase at these heights (Figure 1). While the solar visible light (380 to 780 nm) is nearly constant with the variability of not more than about 0.1% of the solar constant, the solar XUV radiation is highly variable in time and space. For instance, X-ray bursts associated with solar flares can dramatically increase their intensity over preflare levels by many orders of magnitude over some time of tens of minutes. In the extreme ultraviolet, the Lyman α line at 121.6 nm represents an important source of ionization and dissociation at ionospheric D layer heights. During quiet periods of solar activity, it alone contains more energy than the rest of the XUV spectrum. Quasi-periodic changes of the order of 100% or greater, with periods of 27 days and 11 years, belong to the prominent variations of solar XUV radiation. However, irregular fluctuations over all time scales are present all the time. During the low solar activity, about half of the total energy input into the thermosphere is thought to be solar XUV radiation. That solar XUV energy input occurs only during daytime conditions, maximizing at the equator during equinox.

Solar wind
The second source of energy input into the thermosphere is solar wind energy which is transferred to the magnetosphere by mechanisms that are not well understood. One possible way to transfer energy is via a hydrodynamic dynamo process. Solar wind particles penetrate the polar regions of the magnetosphere where the geomagnetic field lines are essentially vertically directed. An electric field is generated, directed from dawn to dusk. Along the last closed geomagnetic field lines with their footpoints within the auroral zones, field-aligned electric currents can flow into the ionospheric dynamo region where they are closed by electric Pedersen and Hall currents. Ohmic losses of the Pedersen currents heat the lower thermosphere (see e.g., Magnetospheric electric convection field). Also, penetration of high energetic particles from the magnetosphere into the auroral regions enhance drastically the electric conductivity, further increasing the electric currents and thus Joule heating. During the quiet magnetospheric activity, the magnetosphere contributes perhaps by a quarter to the thermosphere's energy budget. This is about 250 K of the exospheric temperature in eq.(2). During the very large activity, however, this heat input can increase substantially, by a factor of four or more. That solar wind input occurs mainly in the auroral regions during both day and night.

Atmospheric waves
Two kinds of large-scale atmospheric waves within the lower atmosphere exist: internal waves with finite vertical wavelengths which can transport wave energy upward, and external waves with infinitely large wavelengths that cannot transport wave energy. Atmospheric gravity waves and most of the atmospheric tides generated within the troposphere belong to the internal waves. Their density amplitudes increase exponentially with height so that at the mesopause these waves become turbulent and their energy is dissipated (similar to breaking of ocean waves at the coast), thus contributing to the heating of the thermosphere by about 250 K in eq.(2). On the other hand, the fundamental diurnal tide labeled (1, −2) which is most efficiently excited by solar irradiance is an external wave and plays only a marginal role within the lower and middle atmosphere. However, at thermospheric altitudes, it becomes the predominant wave. It drives the electric Sq-current within the ionospheric dynamo region between about 100 and 200 km height.

Heating, predominately by tidal waves, occurs mainly at lower and middle latitudes. The variability of this heating depends on the meteorological conditions within the troposphere and middle atmosphere, and may not exceed about 50%.

Dynamics
Within the thermosphere above an altitude of about 150 km, all atmospheric waves successively become external waves, and no significant vertical wave structure is visible. The atmospheric wave modes degenerate to the spherical functions Pnm with m a meridional wave number and n the zonal wave number (m = 0: zonal mean flow; m = 1: diurnal tides; m = 2: semidiurnal tides; etc.). The thermosphere becomes a damped oscillator system with low-pass filter characteristics. This means that smaller-scale waves (greater numbers of (n,m)) and higher frequencies are suppressed in favor of large-scale waves and lower frequencies. If one considers very quiet magnetospheric disturbances and a constant mean exospheric temperature (averaged over the sphere), the observed temporal and spatial distribution of the exospheric temperature distribution can be described by a sum of spheric functions:

(3) $$T(\varphi, \lambda, t) = T_\infty \{ 1 + \Delta T_2^0 P_2^0(\varphi) + \Delta T_1^0 P_1^0(\varphi) \cos [ \omega_a (t - t_a) ] + \Delta T_1^1 P_1^1(\varphi) \cos (\tau - \tau_d) + \cdots \}$$

Here, it is φ latitude, λ longitude, and t time, ωa the angular frequency of one year, ωd the angular frequency of one solar day, and τ =  ωdt + λ  the local time. ta = June 21 is the date of northern summer solstice, and τd = 15:00 is the local time of maximum diurnal temperature.

The first term in (3) on the right is the global mean of the exospheric temperature (of the order of 1000 K). The second term [with P20 = 0.5(3 sin2(φ)−1)] represents the heat surplus at lower latitudes and a corresponding heat deficit at higher latitudes (Fig. 2a). A thermal wind system develops with the wind toward the poles in the upper level and winds away from the poles in the lower level. The coefficient ΔT20 ≈ 0.004 is small because Joule heating in the aurora regions compensates that heat surplus even during quiet magnetospheric conditions. During disturbed conditions, however, that term becomes dominant, changing sign so that now heat surplus is transported from the poles to the equator. The third term (with P10 = sin φ) represents heat surplus on the summer hemisphere and is responsible for the transport of excess heat from the summer into the winter hemisphere (Fig. 2b). Its relative amplitude is of the order ΔT10 ≃ 0.13. The fourth term (with P11(φ) = cos φ) is the dominant diurnal wave (the tidal mode (1,−2)). It is responsible for the transport of excess heat from the daytime hemisphere into the nighttime hemisphere (Fig. 2d). Its relative amplitude is ΔT11≃ 0.15, thus on the order of 150 K. Additional terms (e.g., semiannual, semidiurnal terms, and higher-order terms) must be added to eq.(3). However, they are of minor importance. Corresponding sums can be developed for density, pressure, and the various gas constituents.

Thermospheric storms
In contrast to solar XUV radiation, magnetospheric disturbances, indicated on the ground by geomagnetic variations, show an unpredictable impulsive character, from short periodic disturbances of the order of hours to long-standing giant storms of several days' duration. The reaction of the thermosphere to a large magnetospheric storm is called a thermospheric storm. Since the heat input into the thermosphere occurs at high latitudes (mainly into the auroral regions), the heat transport is represented by the term P20 in eq.(3) is reversed. Also, due to the impulsive form of the disturbance, higher-order terms are generated which, however, possess short decay times and thus quickly disappear. The sum of these modes determines the "travel time" of the disturbance to the lower latitudes, and thus the response time of the thermosphere with respect to the magnetospheric disturbance. Important for the development of an ionospheric storm is the increase of the ratio N2/O during a thermospheric storm at middle and higher latitude. An increase of N2 increases the loss process of the ionospheric plasma and causes therefore a decrease of the electron density within the ionospheric F-layer (negative ionospheric storm).

Climate change
A contraction of the thermosphere has been observed as a possible result in part due to increased carbon dioxide concentrations, the strongest cooling and contraction occurring in that layer during solar minimum. The most recent contraction in 2008–2009 was the largest such since at least 1967.

title: Thermosphere


text:
Aten

Aten, also Aton, Atonu, or Itn (jtn, reconstructed ) was the focus of Atenism, the religious system formally established in ancient Egypt by the late Eighteenth Dynasty pharaoh Akhenaten. Exact dating for the Eighteenth Dynasty is contested, though a general date range places the dynasty in the years 1550 to 1292 BCE. The worship of Aten and the coinciding rule of Akhenaten are major identifying characteristics of a period within the Eighteenth Dynasty referred to as the Amarna Period (c. 1353 – 1336 BCE).

Atenism and the worship of the Aten as the sole god of ancient Egypt state worship did not persist beyond Akhenaten's death. Not long after his death, one of Akhenaten's Eighteenth Dynasty successors, Tutankhamun, reopened the state temples to other Egyptian gods and re-positioned Amun as the pre-eminent solar deity. Aten is depicted as a solar disc emitting rays terminating in human hands.

Etymology

The word Aten appears in the Old Kingdom as a noun meaning "disc" which referred to anything flat and circular; the sun was called the "disc of the day" where Ra was thought to reside. By analogy, the term "silver aten" was sometimes used to refer to the moon. High relief and low relief illustrations of the Aten show it with a curved surface, therefore, the late scholar Hugh Nibley insisted that a more correct translation would be globe, orb or sphere, rather than disk.

Origins
The Aten was the disc of the sun and originally an aspect of Ra, the sun god in traditional ancient Egyptian religion. While the Aten was worshiped under the reign of Amenhotep III, it was made the sole deity to receive state and official cult worship under his successor Akhenaten, though archaeological evidence suggests the closing of the state temples of other Egyptian gods likely did not stop household worship of the traditional pantheon. Inscriptions, such as the "Great Hymn to the Aten", found in temples and tombs during Akhenaten's reign showcase the Aten as the creator, giver of life, and nurturing spirit of the world. Aten does not have a creation myth or family but is mentioned in the Book of the Dead. The first known reference to Aten the sun-disk as a deity is in The Story of Sinuhe from the 12th Dynasty, in which the deceased king is described as rising as a god to the heavens and "uniting with the sun-disk, the divine body merging with its maker".

Religion
Aten was extensively worshipped as a solar deity during the reign of Amenhotep III where it was depicted as a falcon-headed god like Ra. While Aten was the preeminent creator deity of a pantheon of ancient Egyptian gods under Amenhotep III, it was not until his successor that Aten would be the only god acknowledged via state worship. During the reign of Amenhotep III's successor, Amenhotep IV, the Aten became the sole god of the Egyptian state religion, and Amenhotep IV changed his name to Akhenaten to reflect his close link with the supreme deity. The sole worship of Aten can be referred to as Atenism. Many of the core principles of Atenism were recorded in the capital city Akhenaten founded and moved his dynastic government to, Akhetaten, referred to as either Amarna, El-Amarna, or Tell el-Amarna by modern scholars.

In Atenism, night is a time to fear. Work is done best when the sun, and thus Aten, is present. The Aten created all countries and people, and cares for every creature. According to the inscriptions, the Aten created a Nile river in the sky (rain) for the Syrians. The rays of the sun disk only holds out life to the royal family, and because of this non-royals receives life from Akhenaten and Nefertiti, later Neferneferuaten, in exchange for loyalty to the Aten. In inscriptions, like the Hymn to the Aten and the King, the Aten is depicted as caring for the people through Akhenaten, placing the royal family as intermediaries for the worship of the Aten. There is only one known instance of the Aten talking.

In the Hymn to Aten, a love for humanity and the Earth is depicted in Aten's mannerisms:

"Aten bends low, near the earth, to watch over his creation; he takes his place in the sky for the same purpose; he wearies himself in the service of the creatures; he shines for them all; he gives them sun and sends them rain. The unborn child and the baby chick are cared for; and Akhenaten asks his divine father to 'lift up' the creatures for his sake so that they might aspire to the condition of perfection of his father, Aten."

Akhenaten represented himself as the son of Aten, mirroring many of his predecessors' claims of divine birth and their positions as the embodiment of Horus. Akhenaten positioned himself as the only intermediary who could speak to Aten, emphasizing the dominance of Aten as the preeminent deity. This has led to discussion of whether Atenism should be considered a monotheistic religion, and thus making it one of the first examples of monotheism.

Aten is both a unique deity and a continuation of the traditional idea of a sun-god in ancient Egyptian religion, deriving a lot of the concepts of power and representation from the earlier solar deities like Ra, but building on top of the power Ra and many of his contemporaries represents. Aten carried absolute power in the universe, representing the life-giving force of light to the world as well as merging with the concept and goddess Ma'at to develop further responsibilities for Aten beyond the power of light itself.

Worship
The cult-center of the Aten was at the capital city Akhenaten founded, Akhetaten, though other cult sites have been found in Thebes and Heliopolis. The use of Amarna as a capital city and religious center was relatively short lived compared to the 18th Dynasty or New Kingdom as a whole as it was shortly abandoned after the death of Akhenaten. Inscriptions found on boundary stela accredited to Akhenaten discuss his desire to make the city a place of worship to Aten, dedicating the city to the god and emphasizing the royal residences' efforts in worship. Major principals of the Aten's cult worship were recorded via inscriptions on temples and tombs from the period. Straying significantly from the tradition of ancient Egyptian temples being hidden and more enclosed the further one went into the site, temples of Aten were open and did not have roofs in order to allow the rays of the sun inside. No statues of Aten were allowed as they were seen as idolatry. However, these were typically replaced by functionally equivalent representations of Akhenaten and his family venerating the Aten and receiving the ankh, the breath of life, from him. Compared to periods before and after the Amarna Period, Priests had less to do since offerings, such as fruits, flowers, and cakes were limited, and oracles were not needed.

In the worship of the Aten, the daily service of purification, anointment, and clothing of the divine image that is traditionally found in ancient Egyptian worship was not performed. Instead, incense and food-stuff offerings such as meats, wines, and fruits were placed onto open-air altars. A common scene in carved depictions of Akhenaten giving offering to Aten has him consecrating the sacrificed goods with a royal scepter. Instead of barque-processions, the royal family rode in a chariot on festival days. Elite women were known to worship the Aten in sun-shade temples in Akhetaten.

Iconography
Aten was considered to have been everywhere and intangible as Aten was the sunlight and energy in the world. Therefore, he did not have physical representations that other traditional ancient Egyptian gods had, instead represented via the sun disc and reaching rays of light tipped with human-like hands. The explanation as to why the Aten could not be fully represented was that the Aten was beyond creation. Thus the inscriptions of scenes of gods carved in stone previously depicted animals and human forms instead showed the Aten as an orb above with life-giving rays stretching toward the royal figure. This power transcended human or animal form.

Later, iconoclasm was enforced, and even sun disc depictions of Aten were prohibited in an edict issued by Akhenaten. In the edict, he stipulated that Aten's name was to be spelt phonetically.

Architecture
Two temples were central to the city of Akhetaten. The larger of the two had an "open, unroofed structure covering an area of about 800 by 300 metres (2,600 ft × 1,000 ft) at the northern end of the city". Doorways had broken lintels and raised thresholds. Temples to the Aten were open-air structures with little-to-no roofing to maximize the amount of sunlight on the interior making them unique compared to other Egyptian temples of the time. Balustrades depict Akhenaten and the royal family embracing the rays of the Aten flanked stairwells, ramps, and altars. These fragments were initially identified as stele but were later reclassified as balustrades based on the presence of scenes on both sides.

Royal titulary
Inscriptions in tombs and temples during the Amarna Period often gave Aten a royal titulary enclosed in a double cartouche. Some have interpreted this to mean that Akhenaten was the embodiment of Aten, and the worship of Aten is directly worship of Akhenaten; but others have taken this as an indicator of Aten as the supreme ruler even over the current reigning royalty.

There were two forms of the title; the first had the names of other gods, and the second later one was more 'singular' and referred only to the Aten himself. The early form was Re-Horakhti who rejoices in the Horizon, in his name Shu, which is the Aten. The later form was Re, ruler of the two horizons, who rejoices in the Horizon, in his name of light, which is the Aten.

Question of monotheism
Ra-Horus, more usually referred to as Ra-Horakhty (Ra who is Horus of the two horizons), is a synthesis of two other gods, both of which are attested from very early on in ancient Egyptian religious practice. During the Amarna Period, this synthesis was seen as the invisible source of energy of the sun god, of which the visible manifestation was the Aten, the solar disk. Thus Ra-Horus-Aten was a development of old ideas which came gradually. The real change, as some see it, was the apparent abandonment of all other gods on the state level, especially Amun-Ra, prohibition of idolatry, and the debatable introduction of quasi-monotheism by Akhenaten. The syncretism is readily apparent in the Great Hymn to the Aten in which Re-Herakhty, Shu, and Aten are merged into the creator god. Others see Akhenaten as a practitioner of an Aten monolatry, as he did not actively deny the existence of other gods; he simply refrained from worshipping any but the Aten. Other scholars call the religion henotheistic.

End of Atenism
As pharaoh, Akhenaten was considered the 'high priest' or even a prophet of the Aten, and during his reign was one of the main propagators of Atenism in Egypt. After the death of Akhenaten, Tutankhamun reinstated the cult of Amun, and the ban on the state worship of non-Atenism deities was lifted in favor of a return to the traditional ancient Egyptian pantheon. The point of this transition can be seen in the name-change of Tutankhaten into Tutankhamun indicating the loss of favor in the worship of the Aten. While there was no purge of the cult after Akhenaten's death, the Aten persisted in Egypt for another ten years or so until it seemed to fade. When Tutankhamun came into power, his religious reign was one of tolerance, with the major difference being that the Aten was no longer the only god worshiped within official, state capacity. Tutankhamun made efforts to rebuild the state temples that were destroyed during Akhenaten's reign and reinstate the traditional pantheon of gods. This seemed to be "a move based publicly on the doctrine that Egypt's woes stemmed directly from its ignoring the gods, and in turn the gods' abandonment of Egypt".

Names derived from Aten

 * Akhenaten: "Effective spirit of the Aten".
 * Akhetaten: "Horizon of the Aten", Akhenaten's capital. The archaeological site is known as Amarna.
 * Ankhesenpaaten: "Her life is of the Aten".
 * Beketaten: "Handmaid of the Aten".
 * Meritaten: "She who is beloved of the Aten".
 * Meketaten: "Behold the Aten" or "Protected by Aten".
 * Neferneferuaten: "Beautiful are the beauties of Aten".
 * Paatenemheb: "The Aten on jubilee".
 * Tutankhaten: "Living image of the Aten". Early name of Tutankhamun.

title: Aten


text:
Mesopause

The mesopause is the point of minimum temperature at the boundary between the mesosphere and the thermosphere atmospheric regions. Due to the lack of solar heating and very strong radiative cooling from carbon dioxide, the mesosphere is the coldest region on Earth with temperatures as low as -100 °C (-148 °F or 173 K). The altitude of the mesopause for many years was assumed to be at around 85 km (53 mi), but observations to higher altitudes and modeling studies in the last 10 years have shown that in fact there are two mesopauses - one at about 85 km and a stronger one at about 100 km (62 mi), with a layer of slightly warmer air between them.

Another feature is that the summer mesopause is cooler than the winter (sometimes referred to as the mesopause anomaly). It is due to a summer-to-winter circulation giving rise to upwelling at the summer pole and downwelling at the winter pole. Air rising will expand and cool resulting in a cold summer mesopause and conversely downwelling air results in compression and associated increase in temperature at the winter mesopause. In the mesosphere the summer-to-winter circulation is due to gravity wave dissipation, which deposits momentum against the mean east–west flow, resulting in a small north–south circulation.

In recent years the mesopause has also been the focus of studies on global climate change associated with increases in CO2. Unlike the troposphere, where greenhouse gases result in the atmosphere heating up, increased CO2 in the mesosphere acts to cool the atmosphere due to increased radiative emission. This results in a measurable effect - the mesopause should become cooler with increased CO2. Observations do show a decrease of temperature of the mesopause, though the magnitude of this decrease varies and is subject to further study. Modeling studies of this phenomenon have also been carried out.

title: Mesopause


text:
Amor

Amor ("love" in Latin, Spanish and Portuguese) may refer to:

Albums

 * Amor (Julio Iglesias album), 1982
 * Amor (Andrea Bocelli album), 2006

Songs

 * "Amor" (Los Auténticos Decadentes song), 2000
 * "Amor" (Cristian Castro song), 1995
 * "Amor" (Gabriel Ruiz song), recorded by Bing Crosby in 1944, Ben E. King in 1961, and Luis Miguel in 2001
 * "Amor" (Ricky Martin song), 2001

Other uses

 * Amor (name), a list of notable people with the name
 * Amor, the Roman deity Cupid
 * 1221 Amor, an asteroid
 * Amor asteroid, a group of near-Earth asteroids named after 1221 Amor
 * Amor (automobile), a German car
 * Amor (film), a 1940 Argentine comedy
 * WAMR-FM, branded as 107.5 Amor,a radio station in Miami, Florida
 * WPAT-FM, branded as 93.1 Amor, a radio station in Paterson, New Jersey

title: Amor


text:
Apollo asteroid

The Apollo asteroids are a group of near-Earth asteroids named after 1862 Apollo, discovered by German astronomer Karl Reinmuth in the 1930s. They are Earth-crossing asteroids that have an orbital semi-major axis greater than that of the Earth (a > 1 AU) but perihelion distances less than the Earth's aphelion distance (q < 1.017 AU).

, the number of known Apollo asteroids is 18,874, making the class the largest group of near-Earth objects (cf. the Aten, Amor and Atira asteroids), of which 1,571 are numbered (asteroids are not numbered until they have been observed at two or more oppositions), and 2,041 are identified as potentially hazardous asteroids.

The closer their semi-major axis is to Earth's, the less eccentricity is needed for the orbits to cross. The Chelyabinsk meteor, that exploded over the city of Chelyabinsk in the southern Urals region of Russia on February 15, 2013, injuring an estimated 1,500 people with flying glass from broken windows, was an Apollo-class asteroid.

List
The largest known Apollo asteroid is 1866 Sisyphus, with a diameter of about 8.5 km. Examples of known Apollo asteroids include:

title: Apollo asteroid


text:
Algal bloom

An algal bloom or algae bloom is a rapid increase or accumulation in the population of algae in freshwater or marine water systems. It is often recognized by the discoloration in the water from the algae's pigments. The term algae encompasses many types of aquatic photosynthetic organisms, both macroscopic multicellular organisms like seaweed and microscopic unicellular organisms like cyanobacteria. Algal bloom commonly refers to the rapid growth of microscopic unicellular algae, not macroscopic algae. An example of a macroscopic algal bloom is a kelp forest.

Algal blooms are the result of a nutrient, like nitrogen or phosphorus from various sources (for example fertilizer runoff or other forms of nutrient pollution), entering the aquatic system and causing excessive growth of algae. An algal bloom affects the whole ecosystem.

Consequences range from the benign feeding of higher trophic levels to more harmful effects like blocking sunlight from reaching other organisms, causing a depletion of oxygen levels in the water, and, depending on the organism, secreting toxins into the water. Blooms that can injure animals or the ecology, especially those blooms where toxins are secreted by the algae, are usually called "harmful algal blooms" (HAB), and can lead to fish die-offs, cities cutting off water to residents, or states having to close fisheries. The process of the oversupply of nutrients leading to algae growth and oxygen depletion is called eutrophication.

Algal and bacterial blooms have persistently contributed to mass extinctions driven by global warming in the geologic past, such as during the end-Permian extinction driven by Siberian Traps volcanism and the biotic recovery following the mass extinction.

Characterization
The term algal bloom is defined inconsistently depending on the scientific field and can range from a "minibloom" of harmless algae to a large, harmful bloom event. Since algae is a broad term including organisms of widely varying sizes, growth rates, and nutrient requirements, there is no officially recognized threshold level as to what is defined as a bloom. Because there is no scientific consensus, blooms can be characterized and quantified in several ways: measurements of new algal biomass, the concentration of photosynthetic pigment, quantification of the bloom's negative effect, or relative concentration of the algae compared to the rest of the microbial community. For example, definitions of blooms have included when the concentration of chlorophyll exceeds 100 ug/L, when the concentration of chlorophyll exceeds 5 ug/L, when the species considered to be blooming exceeds concentrations of 1000 cells/mL, and when the algae species concentration simply deviates from its normal growth.

Blooms are the result of a nutrient needed by the particular algae being introduced to the local aquatic system. This growth-limiting nutrient is typically nitrogen or phosphorus, but can also be iron, vitamins, or amino acids. There are several mechanisms for the addition of these nutrients in water. In the open ocean and along coastlines, upwelling from both winds and topographical ocean floor features can draw nutrients to the photic, or sunlit zone of the ocean. Along coastal regions and in freshwater systems, agricultural, city, and sewage runoff can cause algal blooms.

Algal blooms, especially large algal bloom events, can reduce the transparency of the water and can discolor the water. The photosynthetic pigments in the algal cells, like chlorophyll and photoprotective pigments, determine the color of the algal bloom. Depending on the organism, its pigments, and the depth in the water column, algal blooms can be green, red, brown, golden, and purple. Bright green blooms in freshwater systems are frequently a result of cyanobacteria (colloquially known as "blue-green algae") such as Microcystis. Blooms may also consist of macroalgal (non-phytoplanktonic) species. These blooms are recognizable by large blades of algae that may wash up onto the shoreline.

Once the nutrient is present in the water, the algae begin to grow at a much faster rate than usual. In a mini bloom, this fast growth benefits the whole ecosystem by providing food and nutrients for other organisms.

Of particular note are the harmful algal blooms (HABs), which are algal bloom events involving toxic or otherwise harmful phytoplankton. Many species can cause harmful algal blooms. For example, Gymnodinium nagasakiense can cause harmful red tides, dinoflagellates Gonyaulax polygramma can cause oxygen depletion and result in large fish kills, cyanobacteria Microcystis aeruginosa can make poisonous toxins, and diatom Chaetoceros convolutus can damage fish gills.

Freshwater algal blooms
Freshwater algal blooms are the result of an excess of nutrients, particularly some phosphates. Excess nutrients may originate from fertilizers that are applied to land for agricultural or recreational purposes and may also originate from household cleaning products containing phosphorus.

The reduction of phosphorus inputs is required to mitigate blooms that contain cyanobacteria. In lakes that are stratified in the summer, autumn turnover can release substantial quantities of bio-available phosphorus potentially triggering algal blooms as soon as sufficient photosynthetic light is available. Excess nutrients can enter watersheds through water runoff. Excess carbon and nitrogen have also been suspected as causes. Presence of residual sodium carbonate acts as catalyst for the algae to bloom by providing dissolved carbon dioxide for enhanced photosynthesis in the presence of nutrients.

When phosphates are introduced into water systems, higher concentrations cause increased growth of algae and plants. Algae tend to grow very quickly under high nutrient availability, but each alga is short-lived, and the result is a high concentration of dead organic matter which starts to decompose. Natural decomposers present in the water begin decomposing the dead algae, consuming dissolved oxygen present in the water during the process. This can result in a sharp decrease in available dissolved oxygen for other aquatic life. Without sufficient dissolved oxygen in the water, animals and plants may die off in large numbers. This may also be known as a dead zone.

Blooms may be observed in freshwater aquariums when fish are overfed and excess nutrients are not absorbed by plants. These are generally harmful for fish, and the situation can be corrected by changing the water in the tank and then reducing the amount of food given.

Marine algal blooms

Turbulent storms churn the ocean in summer, adding nutrients to sunlit waters near the surface. This sparks a feeding frenzy each spring that gives rise to massive blooms of phytoplankton. Tiny molecules found inside these microscopic plants harvest vital energy from sunlight through photosynthesis. The natural pigments, called chlorophyll, allow phytoplankton to thrive in Earth's oceans and enable scientists to monitor blooms from space. Satellites reveal the location and abundance of phytoplankton by detecting the amount of chlorophyll present in coastal and open waters—the higher the concentration, the larger the bloom. Observations show blooms typically last until late spring or early summer, when nutrient stocks are in decline and predatory zooplankton start to graze. The visualization on the left immediately below uses NASA SeaWiFS data to map bloom populations.

The NAAMES study conducted between 2015 and 2019 investigated aspects of phytoplankton dynamics in ocean ecosystems, and how such dynamics influence atmospheric aerosols, clouds, and climate.

In France, citizens are requested to report coloured waters through the project PHENOMER. This helps to understand the occurrence of marine blooms.

Wildfires can cause phytoplankton blooms via oceanic deposition of wildfire aerosols.

Harmful algal blooms

A harmful algal bloom (HAB) is an algal bloom that causes negative impacts to other organisms via production of natural toxins, mechanical damage to other organisms, or by other means. The diversity of these HABs make them even harder to manage, and present many issues, especially to threatened coastal areas. HABs are often associated with large-scale marine mortality events and have been associated with various types of shellfish poisonings. Due to their negative economic and health impacts, HABs are often carefully monitored.

HAB has been proved to be harmful to humans. Humans may be exposed to toxic algae by direct consuming seafood containing toxins, swimming or other activities in water, and breathing tiny droplets in the air that contain toxins. Because human exposure can take place by consuming seafood products that contain the toxins expelled by HAB algae, food-borne diseases are present and can affect the nervous, digestive, respiratory, hepatic, dermatological, and cardiac systems in the body. Beach users have often experienced upper respiratory diseases, eye and nose irritation, fever, and have often needed medical care in order to be treated. Ciguatera fish poisoning (CFP) is very common from the exposure of algal blooms. Water-borne diseases are also present as our drinking waters can be contaminated by cyanotoxins.

If the HAB event results in a high enough concentration of algae the water may become discoloured or murky, varying in colour from purple to almost pink, normally being red or green. Not all algal blooms are dense enough to cause water discolouration.

Bioluminescence
Dinoflagellates are microbial eukaryotes that link bioluminesce and toxin production in algal blooms. They use a luciferin-luciferase reaction to create a blue light emission glow. There are seventeen major types of dinoflagellate toxins, in which the strains, Saxitoxin and Yessotoxin, are both bioluminescent and toxic. These two strains are found to have similar niches in coastal areas. A surplus of Dinoflagellates in the night time creates a blue-green glow, however, in the day, it presents as a red brown color which names algal blooms, Red Tides. Dinoflagellates have been reported to be the cause of seafood poisoning from the neurotoxins.

Management
There are three major categories for management of Algal blooms consisting of mitigation, prevention, and control, Within mitigation, routine monitoring programs are implemented for toxins in shellfish and an overall surveillance of the area. The HAB levels of the shellfish will be determined and can manage restrictions to keep contaminated shellfish off the food market. Moving fish pens away from algal blooms is also another form of mitigation. Within prevention, this category is less known but policy changes are implemented to control sewage and waste. Within control, there are mechanical, biological, chemical, genetic and environmental controls. Mechanical control involves dispersing clay into the water to aggregate with the HAB leading to less of these HAB to go through the process of sedimentation. Biological control varies largely and can be used through pheromones or releasing sterile males to reduce reproduction. Chemical control uses toxic chemical release. However, it may cause problems of mortality of other non targeted organisms. Genetic control involves genetically engineering species in their environmental tolerances and reproduction processes. However, there are problems of harming indigenous organisms. For environmental control, it can use water circulation and aeration.

title: Algal bloom