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All your base are belong to us

"All your base are belong to us" is an Internet meme based on a poorly translated phrase from the opening cutscene of the Japanese video game Zero Wing. The phrase first appeared on the European release of the 1991 Sega Mega Drive, also known as the Sega Genesis, port of the 1989 Japanese arcade game.

By the early 2000s, a GIF animation depicting the opening text became widespread on web forums. A music video accompanied by an EDM remix of the clip, originally posted on the comedy forum Something Awful, gained popularity and became a derivative Internet meme in its own right. The original meme has been referenced many times in media outside of the forums.

Zero Wing transcript
Below are some other examples of text as it appeared in the poorly translated English release, alongside a more accurate translation from the original Japanese.

History
Zero Wing was released in Japanese arcades by developer Toaplan on 1 July 1989, and in North America in April 1990. The European release of the game on the Sega Mega Drive, also known as the Sega Genesis, which contained the script of the meme's origin, occurred in July 1991.

The first references of the meme could be seen in 1999 and the early 2000s when an animated GIF of the scene appeared on forums and sites like Zany Video Game Quotes, OverClocked, and TribalWar forums. In November 2000, Kansas City computer programmer and part-time disc jockey Jeffrey Ray Roberts (1977–2011), of the gabber band The Laziest Men on Mars, made a techno dance track, "Invasion of the Gabber Robots," which remixed some of the Zero Wing video game music with a voice-over of the phrase, "All your base are belong to us". (The original music for Zero Wing was written by Tatsuya Uemura and arranged by Noriyuki Iwadare.) On 16 February 2001, user Bad_CRC posted an animated music video accompanying the song onto the Flash game and animation sharing site Newgrounds. The video was shared rapidly, soon becoming an Internet meme and receiving widespread media attention. The meme's popularity was seen throughout the early 2000s when it was broadcast unauthorized onto the ticker of a Raleigh, North Carolina TV channel, used as a placeholder message by YouTube while under maintenance, and reproduced onto T-shirts.

The meme was addressed by Toaplan representatives Tatsuya Uemura (programmer and music composer of Zero Wing and Toaplan founding member) and Masahiro Yuge (fellow Toaplan composer and founder) in interviews during the 2010s. Uemura stated that the poor English translation in the Mega Drive version was handled by a member of Toaplan in charge of export and overseas business.

The 15th and 20th anniversaries of the posting of the remix on Newgrounds were recognized by numerous culture sites. The meme has been highlighted for its uniqueness in that, unlike other memes of the time, it lacked sexual innuendos or vulgarity.

Mentions in media
The phrase or some variation of lines from the game has appeared numerous times in films, commercials, news broadcasts, other games, and social media posts.

On 12 March 2001, American comic strip Foxtrot featured the phrase spoken by one of the strip's main characters, Jason Fox. Jason approaches his parents, speaking the phrase, much to their confusion, speaking it twice more before leaving while laughing.

In Empire Earth, a 2001 real-time strategy video game developed by Stainless Steel Studios, "All your base are belong to us" is a cheat code that can be used by the player during the game to obtain 100,000 of all resources. Additionally, "Somebody set up us the bomb" is another code that gives the player an instant victory.

On 1 April 2003, in Sturgis, Michigan, seven people placed signs through the town that read: "All your base are belong to us. You have no chance to survive make your time." They claimed to be playing an April Fools' joke, but most people who saw the signs were unfamiliar with the phrase. Many residents were upset that the signs appeared while the US was at war with Iraq, and police chief Eugene Alli said the signs could be "a borderline terrorist threat, depending on what someone interprets it to mean".

In February 2004, North Carolina State University students and members of TheWolfWeb in Raleigh, North Carolina, exploited a web-based service used by local schools and businesses to report weather-related closures to display the phrase within a news ticker on a live news broadcast on News 14 Carolina.

On 1 June 2006, the phrase "ALL YOUR VIDEO ARE BELONG TO US" appeared below the YouTube logo as a placeholder while YouTube was under maintenance. Some users believed the site had been hacked, leading YouTube to add the message "No, we haven't be [sic] hacked. Get a sense of humor."

Counter-Strike: Source and Counter-Strike: Global Offensive, two tactical multiplayer first-person shooters developed by Valve, both feature the phrase "Someone Set Up Us The Bomb" as one of the game's achievements.

On 19 January 2019, American Congresswoman Alexandria Ocasio-Cortez (D-NY) tweeted "All your base (are) belong to us" in response to a poll by "Hill-HarrisX" indicating that 45% of the Republicans who were polled approved of Ocasio-Cortez's suggested implementation of a 70% marginal tax rate for individual income over $10 million per year.

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

title: All your base are belong to us


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Boreal

Boreal may refer to:

Climatology and geography

 * Boreal (age), the first climatic phase of the Blytt-Sernander sequence of northern Europe, during the Holocene epoch
 * Boreal climate, a climate characterized by long winters and short, cool to mild summers
 * Boreal ecosystem, an ecosystem with a subarctic climate in the Northern Hemisphere
 * Boreal forest, a biome characterized by coniferous forests
 * Boreal Sea, a Mesozoic-era seaway

Companies and organizations

 * Boreale, a Quebec microbrewery
 * Boreal Mountain Resort, a ski resort in the Lake Tahoe area of California
 * Boreal Norge, a Norwegian public transport operator
 * Collège Boréal, a francophone college in Ontario, Canada

Other uses

 * Boreal (horse), a racehorse
 * Carlo Boreal, a fictional character in Philip Pullman's His Dark Materials trilogy
 * Le Boreal, a French cruise ship
 * Borealism, the exoticisation of the northern regions of the Earth and their cultures

title: Boreal


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Northern

Northern may refer to the following:

Geography

 * North, a point in direction
 * Northern Europe, the northern part or region of Europe
 * Northern Highland, a region of Wisconsin, United States
 * Northern Province, Sri Lanka
 * Northern Range, a range of hills in Trinidad

Schools

 * Northern Collegiate Institute and Vocational School (NCIVS), a school in Sarnia, Canada
 * Northern Secondary School, Toronto, Canada
 * Northern Secondary School (Sturgeon Falls), Ontario, Canada
 * Northern University (disambiguation), various institutions
 * Northern Guilford High School, a public high school in Greensboro, North Carolina

Companies

 * Arriva Rail North, a former train operating company in northern England
 * Chemins de fer du Nord (Northern Railway Company), a former rail transport company in northern France
 * Nord-Aviation (Northern Aviation), a former state-owned French aircraft manufacturer.
 * Northern Bank, commercial bank in Northern Ireland
 * Northern Foods, based in Leeds, England
 * Northern Pictures, an Australian-based television production company
 * Northern Rail, a former train operating company in northern England
 * Northern Railway of Canada, a defunct railway in Ontario
 * Northern Records, a Southern California independent record label
 * Northern Store, a food and general merchandise store owned and operated by The North West Company
 * Northern Trains, a train operating company in northern England
 * Northern Trust, an international financial services company based in Chicago, Illinois

Transport

 * Northern (automobile), an early American car
 * Northern line, a part of the London Underground network
 * Northern line (Merseyrail), a part of the Merseyrail network
 * Northern line (Sri Lanka)
 * Northern Line (Sydney)
 * Northern Line (Thailand)
 * Northern Railway (disambiguation), various railroads
 * Northern Explorer, a New Zealand long distance train
 * Northern locomotive, a type of (4-8-4) steam locomotive

Other uses

 * Bradford Northern, former name of the Bradford Bulls, a British rugby league football club
 * Northern (Australian film genre), a sub-genre of the Australian Western
 * Northern (genre), a genre of Western films set in Canada or Alaska
 * Northern AFC, an association football club based in Dunedin, New Zealand
 * Northern (constituency), various districts
 * Northern Hotel, a historic hotel in Billings, Montana
 * Northern Hotel (Nevada), a former hotel in Ely, Nevada
 * Northern pike, fish often called a "northern"

title: Northern


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Brightness temperature

Brightness temperature or radiance temperature is a measure of the intensity of electromagnetic energy coming from a source. In particular, it is the temperature at which a black body would have to be in order to duplicate the observed intensity of a grey body object at a frequency $$\nu$$. This concept is used in radio astronomy, planetary science, materials science and climatology.

The brightness temperature provides "a more physically recognizable way to describe intensity".

When the electromagnetic radiation observed is thermal radiation emitted by an object simply by virtue of its temperature, then the actual temperature of the object will always be equal to or higher than the brightness temperature. Since the emissivity is limited by 1, the brightness temperature is a lower bound of the object’s actual temperature.

For radiation emitted by a non-thermal source such as a pulsar, synchrotron, maser, or a laser, the brightness temperature may be far higher than the actual temperature of the source. In this case, the brightness temperature is simply a measure of the intensity of the radiation as it would be measured at the origin of that radiation.

In some applications, the brightness temperature of a surface is determined by an optical measurement, for example using a pyrometer, with the intention of determining the real temperature. As detailed below, the real temperature of a surface can in some cases be calculated by dividing the brightness temperature by the emissivity of the surface. Since the emissivity is a value between 0 and 1, the real temperature will be greater than or equal to the brightness temperature. At high frequencies (short wavelengths) and low temperatures, the conversion must proceed through Planck's law.

The brightness temperature is not a temperature as ordinarily understood. It characterizes radiation, and depending on the mechanism of radiation can differ considerably from the physical temperature of a radiating body (though it is theoretically possible to construct a device which will heat up by a source of radiation with some brightness temperature to the actual temperature equal to brightness temperature).

Nonthermal sources can have very high brightness temperatures. In pulsars the brightness temperature can reach 1030 K. For the radiation of a helium–neon laser with a power of 1 mW, a frequency spread Δf = 1 GHz, an output aperture of 1 mm$2$, and a beam dispersion half-angle of 0.56 mrad, the brightness temperature would be $1.5 K$.

For a black body, Planck's law gives: $$I_\nu = \frac{2 h\nu^3}{c^2} \frac{1}{e^{\frac{h\nu}{kT}}-1}$$ where $$I_\nu$$ (the Intensity or Brightness) is the amount of energy emitted per unit surface area per unit time per unit solid angle and in the frequency range between $$\nu$$ and $$\nu + d\nu$$; $$T$$ is the temperature of the black body; $$h$$ is the Planck constant; $$\nu$$ is frequency; $$c$$ is the speed of light; and $$k$$ is the Boltzmann constant.

For a grey body the spectral radiance is a portion of the black body radiance, determined by the emissivity $$\epsilon$$. That makes the reciprocal of the brightness temperature: $$T_b^{-1} = \frac{k}{h\nu}\, \text{ln}\left[1 + \frac{e^{\frac{h\nu}{kT}}-1}{\epsilon}\right]$$

At low frequency and high temperatures, when $$h\nu \ll kT$$, we can use the Rayleigh–Jeans law: $$I_{\nu} = \frac{2 \nu^2k T}{c^2}$$ so that the brightness temperature can be simply written as: $$T_b=\epsilon T\,$$

In general, the brightness temperature is a function of $$\nu$$, and only in the case of blackbody radiation it is the same at all frequencies. The brightness temperature can be used to calculate the spectral index of a body, in the case of non-thermal radiation.

Calculating by frequency
The brightness temperature of a source with known spectral radiance can be expressed as: $$T_b=\frac{h\nu}{k} \ln^{-1}\left( 1 + \frac{2h\nu^3}{I_{\nu}c^2} \right)$$

When $$h\nu \ll kT$$ we can use the Rayleigh–Jeans law: $$T_b=\frac{I_{\nu}c^2}{2k\nu^2}$$

For narrowband radiation with very low relative spectral linewidth $$\Delta\nu \ll \nu$$ and known radiance $$I$$ we can calculate the brightness temperature as: $$T_b=\frac{I c^2}{2k\nu^2\Delta\nu}$$

Calculating by wavelength
Spectral radiance of black-body radiation is expressed by wavelength as: $$I_{\lambda}=\frac{2 hc^2}{\lambda^5}\frac{1}{ e^{\frac{hc}{kT \lambda}} - 1}$$

So, the brightness temperature can be calculated as: $$T_b=\frac{hc}{k\lambda} \ln^{-1}\left(1 + \frac{2hc^2}{I_{\lambda}\lambda^5} \right)$$

For long-wave radiation $$hc/\lambda \ll kT$$ the brightness temperature is: $$T_b = \frac{I_{\lambda}\lambda^4}{2kc}$$

For almost monochromatic radiation, the brightness temperature can be expressed by the radiance $$I$$ and the coherence length $$L_c$$: $$T_b = \frac{\pi I \lambda^2 L_c}{4kc \ln{2} }$$

In oceanography
In oceanography, the microwave brightness temperature, as measured by satellites looking at the ocean surface, depends on salinity as well as on the temperature and roughness (e.g. from wind-driven waves) of the water.

title: Brightness temperature


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Calibration

In measurement technology and metrology, calibration is the comparison of measurement values delivered by a device under test with those of a calibration standard of known accuracy. Such a standard could be another measurement device of known accuracy, a device generating the quantity to be measured such as a voltage, a sound tone, or a physical artifact, such as a meter ruler.

The outcome of the comparison can result in one of the following:

 * no significant error being noted on the device under test
 * a significant error being noted but no adjustment made
 * an adjustment made to correct the error to an acceptable level

Strictly speaking, the term "calibration" means just the act of comparison and does not include any subsequent adjustment.

The calibration standard is normally traceable to a national or international standard held by a metrology body.

BIPM Definition
The formal definition of calibration by the International Bureau of Weights and Measures (BIPM) is the following: "Operation that, under specified conditions, in a first step, establishes a relation between the quantity values with measurement uncertainties provided by measurement standards and corresponding indications with associated measurement uncertainties (of the calibrated instrument or secondary standard) and, in a second step, uses this information to establish a relation for obtaining a measurement result from an indication." This definition states that the calibration process is purely a comparison, but introduces the concept of measurement uncertainty in relating the accuracies of the device under test and the standard.

Modern calibration processes
The increasing need for known accuracy and uncertainty and the need to have consistent and comparable standards internationally has led to the establishment of national laboratories. In many countries a National Metrology Institute (NMI) will exist which will maintain primary standards of measurement (the main SI units plus a number of derived units) which will be used to provide traceability to customer's instruments by calibration.

The NMI supports the metrological infrastructure in that country (and often others) by establishing an unbroken chain, from the top level of standards to an instrument used for measurement. Examples of National Metrology Institutes are NPL in the UK, NIST in the United States, PTB in Germany and many others. Since the Mutual Recognition Agreement was signed it is now straightforward to take traceability from any participating NMI and it is no longer necessary for a company to obtain traceability for measurements from the NMI of the country in which it is situated, such as the National Physical Laboratory in the UK.

Quality of calibration
To improve the quality of the calibration and have the results accepted by outside organizations it is desirable for the calibration and subsequent measurements to be "traceable" to the internationally defined measurement units. Establishing traceability is accomplished by a formal comparison to a standard which is directly or indirectly related to national standards (such as NIST in the USA), international standards, or certified reference materials. This may be done by national standards laboratories operated by the government or by private firms offering metrology services.

Quality management systems call for an effective metrology system which includes formal, periodic, and documented calibration of all measuring instruments. ISO 9000 and ISO 17025 standards require that these traceable actions are to a high level and set out how they can be quantified.

To communicate the quality of a calibration the calibration value is often accompanied by a traceable uncertainty statement to a stated confidence level. This is evaluated through careful uncertainty analysis. Some times a DFS (Departure From Spec) is required to operate machinery in a degraded state. Whenever this does happen, it must be in writing and authorized by a manager with the technical assistance of a calibration technician.

Measuring devices and instruments are categorized according to the physical quantities they are designed to measure. These vary internationally, e.g., NIST 150-2G in the U.S. and NABL-141 in India. Together, these standards cover instruments that measure various physical quantities such as electromagnetic radiation (RF probes), sound (sound level meter or noise dosimeter), time and frequency (intervalometer), ionizing radiation (Geiger counter), light (light meter), mechanical quantities (limit switch, pressure gauge, pressure switch), and, thermodynamic or thermal properties (thermometer, temperature controller). The standard instrument for each test device varies accordingly, e.g., a dead weight tester for pressure gauge calibration and a dry block temperature tester for temperature gauge calibration.

Instrument calibration prompts
Calibration may be required for the following reasons:
 * a new instrument
 * after an instrument has been repaired or modified
 * moving from one location to another location
 * when a specified time period has elapsed
 * when a specified usage (operating hours) has elapsed
 * before and/or after a critical measurement
 * after an event, for example
 * after an instrument has been exposed to a shock, vibration, or physical damage, which might potentially have compromised the integrity of its calibration
 * sudden changes in weather
 * whenever observations appear questionable or instrument indications do not match the output of surrogate instruments
 * as specified by a requirement, e.g., customer specification, instrument manufacturer recommendation.

In general use, calibration is often regarded as including the process of adjusting the output or indication on a measurement instrument to agree with value of the applied standard, within a specified accuracy. For example, a thermometer could be calibrated so the error of indication or the correction is determined, and adjusted (e.g. via calibration constants) so that it shows the true temperature in Celsius at specific points on the scale. This is the perception of the instrument's end-user. However, very few instruments can be adjusted to exactly match the standards they are compared to. For the vast majority of calibrations, the calibration process is actually the comparison of an unknown to a known and recording the results.

Purpose and scope
The calibration process begins with the design of the measuring instrument that needs to be calibrated. The design has to be able to "hold a calibration" through its calibration interval. In other words, the design has to be capable of measurements that are "within engineering tolerance" when used within the stated environmental conditions over some reasonable period of time. Having a design with these characteristics increases the likelihood of the actual measuring instruments performing as expected. Basically, the purpose of calibration is for maintaining the quality of measurement as well as to ensure the proper working of particular instrument.

Frequency
The exact mechanism for assigning tolerance values varies by country and as per the industry type. The measuring of equipment is manufacturer generally assigns the measurement tolerance, suggests a calibration interval (CI) and specifies the environmental range of use and storage. The using organization generally assigns the actual calibration interval, which is dependent on this specific measuring equipment's likely usage level. The assignment of calibration intervals can be a formal process based on the results of previous calibrations. The standards themselves are not clear on recommended CI values:
 * ISO 17025
 * "A calibration certificate (or calibration label) shall not contain any recommendation on the calibration interval except where this has been agreed with the customer. This requirement may be superseded by legal regulations.”
 * ANSI/NCSL Z540
 * "...shall be calibrated or verified at periodic intervals established and maintained to assure acceptable reliability..."
 * ISO-9001
 * "Where necessary to ensure valid results, measuring equipment shall...be calibrated or verified at specified intervals, or prior to use...”
 * MIL-STD-45662A
 * "... shall be calibrated at periodic intervals established and maintained to assure acceptable accuracy and reliability...Intervals shall be shortened or may be lengthened, by the contractor, when the results of previous calibrations indicate that such action is appropriate to maintain acceptable reliability."

Standards required and accuracy
The next step is defining the calibration process. The selection of a standard or standards is the most visible part of the calibration process. Ideally, the standard has less than 1/4 of the measurement uncertainty of the device being calibrated. When this goal is met, the accumulated measurement uncertainty of all of the standards involved is considered to be insignificant when the final measurement is also made with the 4:1 ratio. This ratio was probably first formalized in Handbook 52 that accompanied MIL-STD-45662A, an early US Department of Defense metrology program specification. It was 10:1 from its inception in the 1950s until the 1970s, when advancing technology made 10:1 impossible for most electronic measurements.

Maintaining a 4:1 accuracy ratio with modern equipment is difficult. The test equipment being calibrated can be just as accurate as the working standard. If the accuracy ratio is less than 4:1, then the calibration tolerance can be reduced to compensate. When 1:1 is reached, only an exact match between the standard and the device being calibrated is a completely correct calibration. Another common method for dealing with this capability mismatch is to reduce the accuracy of the device being calibrated.

For example, a gauge with 3% manufacturer-stated accuracy can be changed to 4% so that a 1% accuracy standard can be used at 4:1. If the gauge is used in an application requiring 16% accuracy, having the gauge accuracy reduced to 4% will not affect the accuracy of the final measurements. This is called a limited calibration. But if the final measurement requires 10% accuracy, then the 3% gauge never can be better than 3.3:1. Then perhaps adjusting the calibration tolerance for the gauge would be a better solution. If the calibration is performed at 100 units, the 1% standard would actually be anywhere between 99 and 101 units. The acceptable values of calibrations where the test equipment is at the 4:1 ratio would be 96 to 104 units, inclusive. Changing the acceptable range to 97 to 103 units would remove the potential contribution of all of the standards and preserve a 3.3:1 ratio. Continuing, a further change to the acceptable range to 98 to 102 restores more than a 4:1 final ratio.

This is a simplified example. The mathematics of the example can be challenged. It is important that whatever thinking guided this process in an actual calibration be recorded and accessible. Informality contributes to tolerance stacks and other difficult to diagnose post calibration problems.

Also in the example above, ideally the calibration value of 100 units would be the best point in the gauge's range to perform a single-point calibration. It may be the manufacturer's recommendation or it may be the way similar devices are already being calibrated. Multiple point calibrations are also used. Depending on the device, a zero unit state, the absence of the phenomenon being measured, may also be a calibration point. Or zero may be resettable by the user-there are several variations possible. Again, the points to use during calibration should be recorded.

There may be specific connection techniques between the standard and the device being calibrated that may influence the calibration. For example, in electronic calibrations involving analog phenomena, the impedance of the cable connections can directly influence the result.

Manual and automatic calibrations
Calibration methods for modern devices can be manual or automatic.

As an example, a manual process may be used for calibration of a pressure gauge. The procedure requires multiple steps, to connect the gauge under test to a reference master gauge and an adjustable pressure source, to apply fluid pressure to both reference and test gauges at definite points over the span of the gauge, and to compare the readings of the two. The gauge under test may be adjusted to ensure its zero point and response to pressure comply as closely as possible to the intended accuracy. Each step of the process requires manual record keeping.

An automatic pressure calibrator is a device that combines an electronic control unit, a pressure intensifier used to compress a gas such as Nitrogen, a pressure transducer used to detect desired levels in a hydraulic accumulator, and accessories such as liquid traps and gauge fittings. An automatic system may also include data collection facilities to automate the gathering of data for record keeping.

Process description and documentation
All of the information above is collected in a calibration procedure, which is a specific test method. These procedures capture all of the steps needed to perform a successful calibration. The manufacturer may provide one or the organization may prepare one that also captures all of the organization's other requirements. There are clearinghouses for calibration procedures such as the Government-Industry Data Exchange Program (GIDEP) in the United States.

This exact process is repeated for each of the standards used until transfer standards, certified reference materials and/or natural physical constants, the measurement standards with the least uncertainty in the laboratory, are reached. This establishes the traceability of the calibration.

See Metrology for other factors that are considered during calibration process development.

After all of this, individual instruments of the specific type discussed above can finally be calibrated. The process generally begins with a basic damage check. Some organizations such as nuclear power plants collect "as-found" calibration data before any routine maintenance is performed. After routine maintenance and deficiencies detected during calibration are addressed, an "as-left" calibration is performed.

More commonly, a calibration technician is entrusted with the entire process and signs the calibration certificate, which documents the completion of a successful calibration. The basic process outlined above is a difficult and expensive challenge. The cost for ordinary equipment support is generally about 10% of the original purchase price on a yearly basis, as a commonly accepted rule-of-thumb. Exotic devices such as scanning electron microscopes, gas chromatograph systems and laser interferometer devices can be even more costly to maintain.

The 'single measurement' device used in the basic calibration process description above does exist. But, depending on the organization, the majority of the devices that need calibration can have several ranges and many functionalities in a single instrument. A good example is a common modern oscilloscope. There easily could be 200,000 combinations of settings to completely calibrate and limitations on how much of an all-inclusive calibration can be automated.

To prevent unauthorized access to an instrument tamper-proof seals are usually applied after calibration. The picture of the oscilloscope rack shows these, and prove that the instrument has not been removed since it was last calibrated as they will possible unauthorized to the adjusting elements of the instrument. There also are labels showing the date of the last calibration and when the calibration interval dictates when the next one is needed. Some organizations also assign unique identification to each instrument to standardize the record keeping and keep track of accessories that are integral to a specific calibration condition.

When the instruments being calibrated are integrated with computers, the integrated computer programs and any calibration corrections are also under control.

Origins
The words "calibrate" and "calibration" entered the English language as recently as the American Civil War, in descriptions of artillery, thought to be derived from a measurement of the calibre of a gun.

Some of the earliest known systems of measurement and calibration seem to have been created between the ancient civilizations of Egypt, Mesopotamia and the Indus Valley, with excavations revealing the use of angular gradations for construction. The term "calibration" was likely first associated with the precise division of linear distance and angles using a dividing engine and the measurement of gravitational mass using a weighing scale. These two forms of measurement alone and their direct derivatives supported nearly all commerce and technology development from the earliest civilizations until about AD 1800.

Calibration of weights and distances (c. 1100 CE)
Early measurement devices were direct, i.e. they had the same units as the quantity being measured. Examples include length using a yardstick and mass using a weighing scale. At the beginning of the twelfth century, during the reign of Henry I (1100-1135), it was decreed that a yard be "the distance from the tip of the King's nose to the end of his outstretched thumb." However, it wasn't until the reign of Richard I (1197) that we find documented evidence.
 * Assize of Measures
 * "Throughout the realm there shall be the same yard of the same size and it should be of iron."

Other standardization attempts followed, such as the Magna Carta (1225) for liquid measures, until the Mètre des Archives from France and the establishment of the Metric system.

The early calibration of pressure instruments
One of the earliest pressure measurement devices was the Mercury barometer, credited to Torricelli (1643), which read atmospheric pressure using Mercury. Soon after, water-filled manometers were designed. All these would have linear calibrations using gravimetric principles, where the difference in levels was proportional to pressure. The normal units of measure would be the convenient inches of mercury or water.

In the direct reading hydrostatic manometer design on the right, applied pressure Pa pushes the liquid down the right side of the manometer U-tube, while a length scale next to the tube measures the difference of levels. The resulting height difference "H" is a direct measurement of the pressure or vacuum with respect to atmospheric pressure. In the absence of differential pressure both levels would be equal, and this would be used as the zero point. The Industrial Revolution saw the adoption of "indirect" pressure measuring devices, which were more practical than the manometer. An example is in high pressure (up to 50 psi) steam engines, where mercury was used to reduce the scale length to about 60 inches, but such a manometer was expensive and prone to damage. This stimulated the development of indirect reading instruments, of which the Bourdon tube invented by Eugène Bourdon is a notable example.

In the front and back views of a Bourdon gauge on the right, applied pressure at the bottom fitting reduces the curl on the flattened pipe proportionally to pressure. This moves the free end of the tube which is linked to the pointer. The instrument would be calibrated against a manometer, which would be the calibration standard. For measurement of indirect quantities of pressure per unit area, the calibration uncertainty would be dependent on the density of the manometer fluid, and the means of measuring the height difference. From this other units such as pounds per square inch could be inferred and marked on the scale.

title: Calibration


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Carbon cycle

The carbon cycle is that part of the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of Earth. Other major biogeochemical cycles include the nitrogen cycle and the water cycle. Carbon is the main component of biological compounds as well as a major component of many minerals such as limestone. The carbon cycle comprises a sequence of events that are key to making Earth capable of sustaining life. It describes the movement of carbon as it is recycled and reused throughout the biosphere, as well as long-term processes of carbon sequestration (storage) to and release from carbon sinks.

To describe the dynamics of the carbon cycle, a distinction can be made between the fast and slow carbon cycle. The fast carbon cycle is also referred to as the biological carbon cycle. Fast carbon cycles can complete within years, moving substances from atmosphere to biosphere, then back to the atmosphere. Slow or geological cycles (also called deep carbon cycle) can take millions of years to complete, moving substances through the Earth's crust between rocks, soil, ocean and atmosphere.

Humans have disturbed the carbon cycle for many centuries. They have done so by modifying land use and by mining and burning carbon from ancient organic remains (coal, petroleum and gas). Carbon dioxide in the atmosphere has increased nearly 52% over pre-industrial levels by 2020, resulting in global warming. The increased carbon dioxide has also caused a reduction in the ocean's pH value and is fundamentally altering marine chemistry. Carbon dioxide is critical for photosynthesis.

Main compartments
The carbon cycle was first described by Antoine Lavoisier and Joseph Priestley, and popularised by Humphry Davy. The global carbon cycle is now usually divided into the following major reservoirs of carbon (also called carbon pools) interconnected by pathways of exchange:
 * Atmosphere
 * Terrestrial biosphere
 * Ocean, including dissolved inorganic carbon and living and non-living marine biota
 * Sediments, including fossil fuels, freshwater systems, and non-living organic material.
 * Earth's interior (mantle and crust). These carbon stores interact with the other components through geological processes.

The carbon exchanges between reservoirs occur as the result of various chemical, physical, geological, and biological processes. The ocean contains the largest active pool of carbon near the surface of the Earth. The natural flows of carbon between the atmosphere, ocean, terrestrial ecosystems, and sediments are fairly balanced; so carbon levels would be roughly stable without human influence.

Atmosphere
Carbon in the Earth's atmosphere exists in two main forms: carbon dioxide and methane. Both of these gases absorb and retain heat in the atmosphere and are partially responsible for the greenhouse effect. Methane produces a larger greenhouse effect per volume as compared to carbon dioxide, but it exists in much lower concentrations and is more short-lived than carbon dioxide. Thus, carbon dioxide contributes more to the global greenhouse effect than methane.

Carbon dioxide is removed from the atmosphere primarily through photosynthesis and enters the terrestrial and oceanic biospheres. Carbon dioxide also dissolves directly from the atmosphere into bodies of water (ocean, lakes, etc.), as well as dissolving in precipitation as raindrops fall through the atmosphere. When dissolved in water, carbon dioxide reacts with water molecules and forms carbonic acid, which contributes to ocean acidity. It can then be absorbed by rocks through weathering. It also can acidify other surfaces it touches or be washed into the ocean.

Human activities over the past two centuries have increased the amount of carbon in the atmosphere by nearly 50% as of year 2020, mainly in the form of carbon dioxide, both by modifying ecosystems' ability to extract carbon dioxide from the atmosphere and by emitting it directly, e.g., by burning fossil fuels and manufacturing concrete.

In the far future (2 to 3 billion years), the rate at which carbon dioxide is absorbed into the soil via the carbonate–silicate cycle will likely increase due to expected changes in the sun as it ages. The expected increased luminosity of the Sun will likely speed up the rate of surface weathering. This will eventually cause most of the carbon dioxide in the atmosphere to be squelched into the Earth's crust as carbonate. Once the concentration of carbon dioxide in the atmosphere falls below approximately 50 parts per million (tolerances vary among species), C3 photosynthesis will no longer be possible. This has been predicted to occur 600 million years from the present, though models vary.

Once the oceans on the Earth evaporate in about 1.1 billion years from now, plate tectonics will very likely stop due to the lack of water to lubricate them. The lack of volcanoes pumping out carbon dioxide will cause the carbon cycle to end between 1 billion and 2 billion years into the future.

Terrestrial biosphere

The terrestrial biosphere includes the organic carbon in all land-living organisms, both alive and dead, as well as carbon stored in soils. About 500 gigatons of carbon are stored above ground in plants and other living organisms, while soil holds approximately 1,500 gigatons of carbon. Most carbon in the terrestrial biosphere is organic carbon, while about a third of soil carbon is stored in inorganic forms, such as calcium carbonate. Organic carbon is a major component of all organisms living on earth. Autotrophs extract it from the air in the form of carbon dioxide, converting it into organic carbon, while heterotrophs receive carbon by consuming other organisms.

Because carbon uptake in the terrestrial biosphere is dependent on biotic factors, it follows a diurnal and seasonal cycle. In CO2 measurements, this feature is apparent in the Keeling curve. It is strongest in the northern hemisphere because this hemisphere has more land mass than the southern hemisphere and thus more room for ecosystems to absorb and emit carbon.

Carbon leaves the terrestrial biosphere in several ways and on different time scales. The combustion or respiration of organic carbon releases it rapidly into the atmosphere. It can also be exported into the ocean through rivers or remain sequestered in soils in the form of inert carbon. Carbon stored in soil can remain there for up to thousands of years before being washed into rivers by erosion or released into the atmosphere through soil respiration. Between 1989 and 2008 soil respiration increased by about 0.1% per year. In 2008, the global total of CO2 released by soil respiration was roughly 98 billion tonnes, about 3 times more carbon than humans are now putting into the atmosphere each year by burning fossil fuel (this does not represent a net transfer of carbon from soil to atmosphere, as the respiration is largely offset by inputs to soil carbon). There are a few plausible explanations for this trend, but the most likely explanation is that increasing temperatures have increased rates of decomposition of soil organic matter, which has increased the flow of CO2. The length of carbon sequestering in soil is dependent on local climatic conditions and thus changes in the course of climate change.

Ocean
The ocean can be conceptually divided into a surface layer within which water makes frequent (daily to annual) contact with the atmosphere, and a deep layer below the typical mixed layer depth of a few hundred meters or less, within which the time between consecutive contacts may be centuries. The dissolved inorganic carbon (DIC) in the surface layer is exchanged rapidly with the atmosphere, maintaining equilibrium. Partly because its concentration of DIC is about 15% higher but mainly due to its larger volume, the deep ocean contains far more carbon—it is the largest pool of actively cycled carbon in the world, containing 50 times more than the atmosphere —but the timescale to reach equilibrium with the atmosphere is hundreds of years: the exchange of carbon between the two layers, driven by thermohaline circulation, is slow.

Carbon enters the ocean mainly through the dissolution of atmospheric carbon dioxide, a small fraction of which is converted into carbonate. It can also enter the ocean through rivers as dissolved organic carbon. It is converted by organisms into organic carbon through photosynthesis and can either be exchanged throughout the food chain or precipitated into the oceans' deeper, more carbon-rich layers as dead soft tissue or in shells as calcium carbonate. It circulates in this layer for long periods of time before either being deposited as sediment or, eventually, returned to the surface waters through thermohaline circulation.

Oceans are basic (with a current pH value of 8.1 to 8.2). The increase in atmospheric CO2 shifts the pH of the ocean towards neutral in a process called ocean acidification. Oceanic absorption of CO2 is one of the most important forms of carbon sequestering. The projected rate of pH reduction could slow the biological precipitation of calcium carbonates, thus decreasing the ocean's capacity to absorb CO2.

Geosphere
The geologic component of the carbon cycle operates slowly in comparison to the other parts of the global carbon cycle. It is one of the most important determinants of the amount of carbon in the atmosphere, and thus of global temperatures.

Most of the Earth's carbon is stored inertly in the Earth's lithosphere. Much of the carbon stored in the Earth's mantle was stored there when the Earth formed. Some of it was deposited in the form of organic carbon from the biosphere. Of the carbon stored in the geosphere, about 80% is limestone and its derivatives, which form from the sedimentation of calcium carbonate stored in the shells of marine organisms. The remaining 20% is stored as kerogens formed through the sedimentation and burial of terrestrial organisms under high heat and pressure. Organic carbon stored in the geosphere can remain there for millions of years.

Carbon can leave the geosphere in several ways. Carbon dioxide is released during the metamorphism of carbonate rocks when they are subducted into the earth's mantle. This carbon dioxide can be released into the atmosphere and ocean through volcanoes and hotspots. It can also be removed by humans through the direct extraction of kerogens in the form of fossil fuels. After extraction, fossil fuels are burned to release energy and emit the carbon they store into the atmosphere.

Types of dynamic

There is a fast and a slow carbon cycle. The fast cycle operates in the biosphere and the slow cycle operates in rocks. The fast or biological cycle can complete within years, moving carbon from atmosphere to biosphere, then back to the atmosphere. The slow or geological cycle may extend deep into the mantle and can take millions of years to complete, moving carbon through the Earth's crust between rocks, soil, ocean and atmosphere.

The fast carbon cycle involves relatively short-term biogeochemical processes between the environment and living organisms in the biosphere (see diagram at start of article). It includes movements of carbon between the atmosphere and terrestrial and marine ecosystems, as well as soils and seafloor sediments. The fast cycle includes annual cycles involving photosynthesis and decadal cycles involving vegetative growth and decomposition. The reactions of the fast carbon cycle to human activities will determine many of the more immediate impacts of climate change.

The slow (or deep) carbon cycle involves medium to long-term geochemical processes belonging to the rock cycle (see diagram on the right). The exchange between the ocean and atmosphere can take centuries, and the weathering of rocks can take millions of years. Carbon in the ocean precipitates to the ocean floor where it can form sedimentary rock and be subducted into the Earth's mantle. Mountain building processes result in the return of this geologic carbon to the Earth's surface. There the rocks are weathered and carbon is returned to the atmosphere by degassing and to the ocean by rivers. Other geologic carbon returns to the ocean through the hydrothermal emission of calcium ions. In a given year between 10 and 100 million tonnes of carbon moves around this slow cycle. This includes volcanoes returning geologic carbon directly to the atmosphere in the form of carbon dioxide. However, this is less than one percent of the carbon dioxide put into the atmosphere by burning fossil fuels.

Terrestrial carbon in the water cycle

The movement of terrestrial carbon in the water cycle is shown in the diagram on the right and explained below:

 * 1) Atmospheric particles act as cloud condensation nuclei, promoting cloud formation.
 * 2) Raindrops absorb organic and inorganic carbon through particle scavenging and adsorption of organic vapors while falling toward Earth.
 * 3) Burning and volcanic eruptions produce highly condensed polycyclic aromatic molecules (i.e. black carbon) that is returned to the atmosphere along with greenhouse gases such as CO2.
 * 4) Terrestrial plants fix atmospheric CO2 through photosynthesis, returning a fraction back to the atmosphere through respiration. Lignin and celluloses represent as much as 80% of the organic carbon in forests and 60% in pastures.
 * 5) Litterfall and root organic carbon mix with sedimentary material to form organic soils where plant-derived and petrogenic organic carbon is both stored and transformed by microbial and fungal activity.
 * 6) Water absorbs plant and settled aerosol-derived dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) as it passes over forest canopies (i.e. throughfall) and along plant trunks/stems (i.e. stemflow). Biogeochemical transformations take place as water soaks into soil solution and groundwater reservoirs and overland flow occurs when soils are completely saturated, or rainfall occurs more rapidly than saturation into soils.
 * 7) Organic carbon derived from the terrestrial biosphere and in situ primary production is decomposed by microbial communities in rivers and streams along with physical decomposition (i.e. photo-oxidation), resulting in a flux of CO2 from rivers to the atmosphere that are the same order of magnitude as the amount of carbon sequestered annually by the terrestrial biosphere.  Terrestrially-derived macromolecules such as lignin and black carbon are decomposed into smaller components and monomers, ultimately being converted to CO2, metabolic intermediates, or biomass.
 * 8) Lakes, reservoirs, and floodplains typically store large amounts of organic carbon and sediments, but also experience net heterotrophy in the water column, resulting in a net flux of CO2 to the atmosphere that is roughly one order of magnitude less than rivers. Methane production is also typically high in the anoxic sediments of floodplains, lakes, and reservoirs.
 * 9) Primary production is typically enhanced in river plumes due to the export of fluvial nutrients. Nevertheless, estuarine waters are a source of CO2 to the atmosphere, globally.
 * 10) Coastal marshes both store and export blue carbon.  Marshes and wetlands are suggested to have an equivalent flux of CO2 to the atmosphere as rivers, globally.
 * 11) Continental shelves and the open ocean typically absorb CO2 from the atmosphere.
 * 12) The marine biological pump sequesters a small but significant fraction of the absorbed CO2 as organic carbon in marine sediments (see below).

Terrestrial runoff to the ocean

Terrestrial and marine ecosystems are chiefly connected through riverine transport, which acts as the main channel through which erosive terrestrially derived substances enter into oceanic systems. Material and energy exchanges between the terrestrial biosphere and the lithosphere as well as organic carbon fixation and oxidation processes together regulate ecosystem carbon and dioxygen (O2) pools.

Riverine transport, being the main connective channel of these pools, will act to transport net primary productivity (primarily in the form of dissolved organic carbon (DOC) and particulate organic carbon (POC)) from terrestrial to oceanic systems. During transport, part of DOC will rapidly return to the atmosphere through redox reactions, causing "carbon degassing" to occur between land-atmosphere storage layers. The remaining DOC and dissolved inorganic carbon (DIC) are also exported to the ocean. In 2015, inorganic and organic carbon export fluxes from global rivers were assessed as 0.50–0.70 Pg C y−1 and 0.15–0.35 Pg C y−1 respectively. On the other hand, POC can remain buried in sediment over an extensive period, and the annual global terrestrial to oceanic POC flux has been estimated at 0.20 (+0.13,-0.07) Gg C y−1.

Biological pump in the ocean

The ocean biological pump is the ocean's biologically driven sequestration of carbon from the atmosphere and land runoff to the deep ocean interior and seafloor sediments. The biological pump is not so much the result of a single process, but rather the sum of a number of processes each of which can influence biological pumping. The pump transfers about 11 billion tonnes of carbon every year into the ocean's interior. An ocean without the biological pump would result in atmospheric CO2 levels about 400 ppm higher than the present day.

Most carbon incorporated in organic and inorganic biological matter is formed at the sea surface where it can then start sinking to the ocean floor. The deep ocean gets most of its nutrients from the higher water column when they sink down in the form of marine snow. This is made up of dead or dying animals and microbes, fecal matter, sand and other inorganic material.

The biological pump is responsible for transforming dissolved inorganic carbon (DIC) into organic biomass and pumping it in particulate or dissolved form into the deep ocean. Inorganic nutrients and carbon dioxide are fixed during photosynthesis by phytoplankton, which both release dissolved organic matter (DOM) and are consumed by herbivorous zooplankton. Larger zooplankton - such as copepods, egest fecal pellets - which can be reingested, and sink or collect with other organic detritus into larger, more-rapidly-sinking aggregates. DOM is partially consumed by bacteria and respired; the remaining refractory DOM is advected and mixed into the deep sea. DOM and aggregates exported into the deep water are consumed and respired, thus returning organic carbon into the enormous deep ocean reservoir of DIC.

A single phytoplankton cell has a sinking rate around one metre per day. Given that the average depth of the ocean is about four kilometres, it can take over ten years for these cells to reach the ocean floor. However, through processes such as coagulation and expulsion in predator fecal pellets, these cells form aggregates. These aggregates have sinking rates orders of magnitude greater than individual cells and complete their journey to the deep in a matter of days.

About 1% of the particles leaving the surface ocean reach the seabed and are consumed, respired, or buried in the sediments. The net effect of these processes is to remove carbon in organic form from the surface and return it to DIC at greater depths, maintaining a surface-to-deep ocean gradient of DIC. Thermohaline circulation returns deep-ocean DIC to the atmosphere on millennial timescales. The carbon buried in the sediments can be subducted into the earth's mantle and stored for millions of years as part of the slow carbon cycle (see next section).

Sub-processes within slow carbon cycle

Slow or deep carbon cycling is an important process, though it is not as well-understood as the relatively fast carbon movement through the atmosphere, terrestrial biosphere, ocean, and geosphere. The deep carbon cycle is intimately connected to the movement of carbon in the Earth's surface and atmosphere. If the process did not exist, carbon would remain in the atmosphere, where it would accumulate to extremely high levels over long periods of time. Therefore, by allowing carbon to return to the Earth, the deep carbon cycle plays a critical role in maintaining the terrestrial conditions necessary for life to exist.

Furthermore, the process is also significant simply due to the massive quantities of carbon it transports through the planet. In fact, studying the composition of basaltic magma and measuring carbon dioxide flux out of volcanoes reveals that the amount of carbon in the mantle is actually greater than that on the Earth's surface by a factor of one thousand. Drilling down and physically observing deep-Earth carbon processes is evidently extremely difficult, as the lower mantle and core extend from 660 to 2,891 km and 2,891 to 6,371 km deep into the Earth respectively. Accordingly, not much is conclusively known regarding the role of carbon in the deep Earth. Nonetheless, several pieces of evidence—many of which come from laboratory simulations of deep Earth conditions—have indicated mechanisms for the element's movement down into the lower mantle, as well as the forms that carbon takes at the extreme temperatures and pressures of said layer. Furthermore, techniques like seismology have led to a greater understanding of the potential presence of carbon in the Earth's core.

Carbon in the lower mantle

Carbon principally enters the mantle in the form of carbonate-rich sediments on tectonic plates of ocean crust, which pull the carbon into the mantle upon undergoing subduction. Not much is known about carbon circulation in the mantle, especially in the deep Earth, but many studies have attempted to augment our understanding of the element's movement and forms within the region. For instance, a 2011 study demonstrated that carbon cycling extends all the way to the lower mantle. The study analyzed rare, super-deep diamonds at a site in Juina, Brazil, determining that the bulk composition of some of the diamonds' inclusions matched the expected result of basalt melting and crystallisation under lower mantle temperatures and pressures. Thus, the investigation's findings indicate that pieces of basaltic oceanic lithosphere act as the principle transport mechanism for carbon to Earth's deep interior. These subducted carbonates can interact with lower mantle silicates, eventually forming super-deep diamonds like the one found.

However, carbonates descending to the lower mantle encounter other fates in addition to forming diamonds. In 2011, carbonates were subjected to an environment similar to that of 1800 km deep into the Earth, well within the lower mantle. Doing so resulted in the formations of magnesite, siderite, and numerous varieties of graphite. Other experiments—as well as petrologic observations—support this claim, indicating that magnesite is actually the most stable carbonate phase in most part of the mantle. This is largely a result of its higher melting temperature. Consequently, scientists have concluded that carbonates undergo reduction as they descend into the mantle before being stabilised at depth by low oxygen fugacity environments. Magnesium, iron, and other metallic compounds act as buffers throughout the process. The presence of reduced, elemental forms of carbon like graphite would indicate that carbon compounds are reduced as they descend into the mantle.

Polymorphism alters carbonate compounds' stability at different depths within the Earth. To illustrate, laboratory simulations and density functional theory calculations suggest that tetrahedrally coordinated carbonates are most stable at depths approaching the core–mantle boundary. A 2015 study indicates that the lower mantle's high pressure causes carbon bonds to transition from sp2 to sp3 hybridised orbitals, resulting in carbon tetrahedrally bonding to oxygen. CO3 trigonal groups cannot form polymerisable networks, while tetrahedral CO4 can, signifying an increase in carbon's coordination number, and therefore drastic changes in carbonate compounds' properties in the lower mantle. As an example, preliminary theoretical studies suggest that high pressure causes carbonate melt viscosity to increase; the melts' lower mobility as a result of its increased viscosity causes large deposits of carbon deep into the mantle.

Accordingly, carbon can remain in the lower mantle for long periods of time, but large concentrations of carbon frequently find their way back to the lithosphere. This process, called carbon outgassing, is the result of carbonated mantle undergoing decompression melting, as well as mantle plumes carrying carbon compounds up towards the crust. Carbon is oxidised upon its ascent towards volcanic hotspots, where it is then released as CO2. This occurs so that the carbon atom matches the oxidation state of the basalts erupting in such areas.

Carbon in the core
Although the presence of carbon in the Earth's core is well-constrained, recent studies suggest large inventories of carbon could be stored in this region. Shear (S) waves moving through the inner core travel at about fifty percent of the velocity expected for most iron-rich alloys. Because the core's composition is believed to be an alloy of crystalline iron and a small amount of nickel, this seismic anomaly indicates the presence of light elements, including carbon, in the core. In fact, studies using diamond anvil cells to replicate the conditions in the Earth's core indicate that iron carbide (Fe7C3) matches the inner core's wave speed and density. Therefore, the iron carbide model could serve as an evidence that the core holds as much as 67% of the Earth's carbon. Furthermore, another study found that in the pressure and temperature condition of the Earth's inner core, carbon dissolved in iron and formed a stable phase with the same Fe7C3 composition—albeit with a different structure from the one previously mentioned. In summary, although the amount of carbon potentially stored in the Earth's core is not known, recent studies indicate that the presence of iron carbides can explain some of the geophysical observations.

Human influence on fast carbon cycle
Since the industrial revolution, and especially since the end of WWII, human activity has substantially disturbed the global carbon cycle by redistributing massive amounts of carbon from the geosphere. Humans have also continued to shift the natural component functions of the terrestrial biosphere with changes to vegetation and other land use. Man-made (synthetic) carbon compounds have been designed and mass-manufactured that will persist for decades to millennia in air, water, and sediments as pollutants. Climate change is amplifying and forcing further indirect human changes to the carbon cycle as a consequence of various positive and negative feedbacks.

Climate change

Current trends in climate change lead to higher ocean temperatures and acidity, thus modifying marine ecosystems. Also, acid rain and polluted runoff from agriculture and industry change the ocean's chemical composition. Such changes can have dramatic effects on highly sensitive ecosystems such as coral reefs, thus limiting the ocean's ability to absorb carbon from the atmosphere on a regional scale and reducing oceanic biodiversity globally.

The exchanges of carbon between the atmosphere and other components of the Earth system, collectively known as the carbon cycle, currently constitute important negative (dampening) feedbacks on the effect of anthropogenic carbon emissions on climate change. Carbon sinks in the land and the ocean each currently take up about one-quarter of anthropogenic carbon emissions each year.

These feedbacks are expected to weaken in the future, amplifying the effect of anthropogenic carbon emissions on climate change. The degree to which they will weaken, however, is highly uncertain, with Earth system models predicting a wide range of land and ocean carbon uptakes even under identical atmospheric concentration or emission scenarios. Arctic methane emissions indirectly caused by anthropogenic global warming also affect the carbon cycle and contribute to further warming.

Fossil carbon extraction and burning
The largest and one of the fastest growing human impacts on the carbon cycle and biosphere is the extraction and burning of fossil fuels, which directly transfer carbon from the geosphere into the atmosphere. Carbon dioxide is also produced and released during the calcination of limestone for clinker production. Clinker is an industrial precursor of cement.

, about 450 gigatons of fossil carbon have been extracted in total; an amount approaching the carbon contained in all of Earth's living terrestrial biomass. Recent rates of global emissions directly into the atmosphere have exceeded the uptake by vegetation and the oceans. These sinks have been expected and observed to remove about half of the added atmospheric carbon within about a century. Nevertheless, sinks like the ocean have evolving saturation properties, and a substantial fraction (20–35%, based on coupled models) of the added carbon is projected to remain in the atmosphere for centuries to millennia.

Halocarbons
Halocarbons are less prolific compounds developed for diverse uses throughout industry; for example as solvents and refrigerants. Nevertheless, the buildup of relatively small concentrations (parts per trillion) of chlorofluorocarbon, hydrofluorocarbon, and perfluorocarbon gases in the atmosphere is responsible for about 10% of the total direct radiative forcing from all long-lived greenhouse gases (year 2019); which includes forcing from the much larger concentrations of carbon dioxide and methane. Chlorofluorocarbons also cause stratospheric ozone depletion. International efforts are ongoing under the Montreal Protocol and Kyoto Protocol to control rapid growth in the industrial manufacturing and use of these environmentally potent gases. For some applications more benign alternatives such as hydrofluoroolefins have been developed and are being gradually introduced.

Land use changes
Since the invention of agriculture, humans have directly and gradually influenced the carbon cycle over century-long timescales by modifying the mixture of vegetation in the terrestrial biosphere. Over the past several centuries, direct and indirect human-caused land use and land cover change (LUCC) has led to the loss of biodiversity, which lowers ecosystems' resilience to environmental stresses and decreases their ability to remove carbon from the atmosphere. More directly, it often leads to the release of carbon from terrestrial ecosystems into the atmosphere.

Deforestation for agricultural purposes removes forests, which hold large amounts of carbon, and replaces them, generally with agricultural or urban areas. Both of these replacement land cover types store comparatively small amounts of carbon so that the net result of the transition is that more carbon stays in the atmosphere. However, the effects on the atmosphere and overall carbon cycle can be intentionally and/or naturally reversed with reforestation.

title: Carbon cycle


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Queen (chess)

The queen (♕, ♛) is the most powerful piece in the game of chess. It can move any number of squares vertically, horizontally or, combining the powers of the rook and bishop. Each player starts the game with one queen, placed in the middle of the first next to the king. Because the queen is the strongest piece, a pawn is promoted to a queen in the vast majority of cases.

The predecessor to the queen is the ferz, a weak piece only able to move or capture one step diagonally, originating from the Persian game of shatranj. The modern queen gained its power and its modern move in Spain in the 15th century.

Placement and movement
The white queen starts on d1, while the black queen starts on d8. With the chessboard oriented correctly, the white queen starts on a white square and the black queen starts on a black square—thus the mnemonics "queen gets her color", "queen on [her] [own] color", or "the dress [queen piece] matches the shoes [square]" (Latin: servat rēgīna colōrem).

The queen can be moved any number of unoccupied squares in a straight line vertically, horizontally, or diagonally, thus combining the moves of the rook and bishop. The queen captures by moving to the square on which an enemy piece stands.

Although both players start with one queen each, a pawn can be promoted to any of several types of pieces, including a queen, when the pawn is moved to the player's furthest rank (the opponent's first rank). Such a queen created by promotion can be an additional queen or, if the player's queen has been captured, a replacement queen. The queen is by far the most common piece type a pawn is promoted to due to the relative power of a queen; promotion to a queen is colloquially called queening.

Piece value
The queen is typically worth about nine pawns, which is slightly stronger than a rook and a bishop together, but slightly weaker than two rooks, though there are exceptions. It is almost always disadvantageous to exchange the queen for a single piece other than the enemy's queen.

The reason that the queen is stronger than a combination of a rook and bishop, even though they control the same number of squares, is twofold. First, the queen is more mobile than the rook and the bishop, as the entire power of the queen can be transferred to another location in one move, while transferring the entire firepower of a rook and bishop requires two moves, the bishop always being restricted to squares of one color. Second, unlike the bishop, the queen is not hampered by an inability to control squares of the opposite color to the square on which it stands. A factor in favor of the rook and bishop together is that they can attack (or defend) a square twice, while a queen can only do so once. However, experience has shown that this factor is usually less significant than the points favoring the queen.

The queen is strongest when the board is open, the enemy king is poorly defended, or there are loose (i.e. undefended) pieces in the enemy camp. Because of its long range and ability to move in multiple directions, the queen is well-equipped to execute forks. Compared to other long range pieces (i.e. rooks and bishops), the queen is less restricted and stronger in closed positions.

Strategy
A player should generally delay developing the queen, as developing it too quickly can expose it to attacks by enemy pieces, causing the player to lose time removing the queen from danger. Despite this, beginners often the queen early in the game, hoping to plunder the enemy position and deliver an early checkmate, such as the scholar's mate.

Early queen attacks are rare in high-level chess, but there are some openings with early queen development that are used by high-level players. For example, the Scandinavian Defense (1.e4 d5), which often features queen moves by Black on the second and third moves, is considered sound and has been played at the world championship level. Some less common examples have also been observed in high-level games. The Danvers Opening (1.e4 e5 2.Qh5), which is widely characterized as a beginner's opening, has occasionally been played by the American grandmaster Hikaru Nakamura.

A queen exchange often marks the beginning of the endgame, but there are queen endgames, and sometimes queens are exchanged in the opening, long before the endgame. A common goal in the endgame is to promote a pawn to a queen. As the queen has the largest range and mobility, queen and king vs. lone king is an easy win when compared to some other basic mates. Queen and king vs. rook and king is also a win for the player with the queen, but it is not easy.

Queen sacrifice
A queen sacrifice is the deliberate sacrifice of a queen in order to gain a more favorable tactical position. One of the most widely known examples of this was in the game Anderssen–Kieseritzky, 1851, where Anderssen sacrificed a queen (along with three other pieces) to reach checkmate.

History
The queen was originally the counsellor or prime minister or vizier (Sanskrit mantri, Persian farzīn, Arabic firzān, firz or wazīr). Initially, its only move was one square diagonally. Around 1300, its abilities were enhanced to allow it to jump two squares diagonally (onto a same-colored square) for its first move.

The fers changed into the queen over time. The first surviving mention of this piece as a queen or similar is the Latin regina in the Einsiedeln Poem, a 98-line Medieval Latin poem written around 997 and preserved in a monastery at Einsiedeln in Switzerland. Some surviving early medieval pieces depict the piece as a queen. The word fers became grammatically feminized in several languages, such as alferza in Spanish and fierce or fierge in French. The Carmina Burana also refer to the queen as femina (woman) and coniunx (spouse), and the name Amazon has sometimes been seen.

During the great chess reform at the end of the 15th century, Catholic nations kept using an equivalent of Latin domina ("lady"), such as dama in Spanish, donna in Italy, and dame in France, all of which evoke "Our Lady". However, Protestant nations such as Germany and England refused any derivatives of domina as it might have suggested some cult of the Virgin Mary and instead opted for secular terms such as Königin in German and "queen" in English.

In Russian, the piece keeps its Persian name of ferz; koroleva (queen) is colloquial and is never used by professional chess players. However, the names korolevna (king's daughter), tsaritsa (tsar's wife), and baba (old woman) are attested as early as 1694. In Arabic countries, the queen remains termed and, in some cases, depicted as a vizier.

Historian Marilyn Yalom proposes several factors that might have been partly responsible for influencing the piece towards its identity as a queen and its power in modern chess: the prominence of medieval queens such as Eleanor of Aquitaine, Blanche of Castile, and more particularly Isabella I of Castile; the cult of the Virgin Mary; the power ascribed to women in the troubadour tradition of courtly love; and the medieval popularity of chess as a game particularly suitable for women to play on equal terms with men. She points to medieval poetry depicting the Virgin as the chess-queen of God or Fierce Dieu.

Significantly, the earliest surviving treatise to describe the modern movement of the queen (as well as the bishop and pawn), Repetición de amores e arte de axedres con CL iuegos de partido (Discourses on Love and the Art of Chess with 150 Problems) by Luis Ramírez de Lucena, was published during the reign of Isabella I of Castile. Even before that, the Valencian poem Scachs d'amor ("Chess of Love") depicted a chess game between Francesc de Castellví and Narcís de Vinyoles and commented on by Bernat Fenollar, which clearly had the modern moves of the queen and the bishop. Well before the queen's powers expanded, it was already being romantically described as essential to the king's survival, so that when the queen was lost, there was nothing more of value on the board.

Marilyn Yalom wrote that:
 * The chess queen, rather than ferz or similar, is known of in what is now Spain and Portugal only from the 12th century, but started sooner elsewhere.
 * The modern move of the Queen started in Spain during Isabella I's reign, perhaps inspired by her great political power, and spread from there, perhaps being spread by the invention of printing and the 1492 Expulsion from Spain of the Jews who carried the new chess rule with them as they fled.

During the 15th century, the queen's move took its modern form as a combination of the move of the rook and the current move of the bishop. Starting from Spain, this new version – called "queen's chess" (in Italian, scacchi della donna) or, pejoratively, "madwoman's chess" (scacchi alla rabiosa) – spread throughout Europe rapidly, partly due to the advent of the printing press and the popularity of new books on chess. The new rules faced a backlash in some quarters, ranging from anxiety over a powerful female warrior figure to frank abuse against women in general.

At various times, the ability of pawns to be queened was restricted while the original queen was still on the board, so as not to cause scandal by providing the king with more than one queen. An early 12th-century Latin poem refers to a queened pawn as a ferzia, as opposed to the original queen or regina, to account for this.

When the queen was attacked, it was customary to warn the opponent by announcing "gardez la reine" or simply "gardez", similar to the announcement of "check". Some published rules even required this announcement before the queen could be legally captured. This custom was largely abandoned in the 19th century.

In Russia, for a long time, the queen could also move like a knight; some players disapproved of this ability to "gallop like the horse" (knight). The book A History of Chess by H.J.R. Murray, says that William Coxe, who was in Russia in 1772, saw chess played with the queen also moving like a knight. Such an augmented queen piece is now known as the fairy chess piece amazon.

Around 1230, the queen was also independently invented as a piece in Japan, where it formed part of the game of dai shogi. The piece was retained in the smaller and more popular chu shogi, but does not form a part of modern shogi.

Nomenclature
In most languages the piece is known as "queen" or "lady" (e.g. Italian regina or Spanish dama). Asian and Eastern European languages tend to refer to it as vizier, minister or advisor (e.g. Arabic/Persian وزیر wazir (vazir), Russian/Persian ферзь/فرز ferz). In Polish it is known as the hetman, the name of a major historical military-political office, while in Estonian it is called lipp ("flag", "standard").

Unicode
Unicode defines three codepoints for a queen:

♕ U+2655 White Chess Queen

♛ U+265B Black Chess Queen

🨁 U+1FA01 Neutral Chess Queen

title: Queen (chess)


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520s BC

This article concerns the period 529 BC – 520 BC.

Events

 * 529 BC—The Chinese state of Zhoulai is conquered by Wu.
 * 528 BC—Gautama Buddha attains Enlightenment, and begins his ministry.
 * 527 BC - Jain Tirthankara Mahavira attains Moksha, according to the Swetambara Tradition.
 * 527 BC—Peisistratos a tyrant of Athens dies: his son Hippias inherits his power.
 * 526 BC—Psammetichus III succeeds Amasis II as king of Egypt.
 * 526 BC—King Liao of Wu ascends to power in the State of Wu in China during the Zhou Dynasty.
 * 525 BC—Cambyses II, ruler of Persia, conquers Egypt, defeating Psammetichus III. This is considered the end of the Twenty-sixth Dynasty, and the start of the Persian Twenty-seventh Dynasty.
 * c. 525 BC—Coins start to have an image on two sides.
 * 522 BC—Bardiya succeeds Cambyses II as ruler of Persia.
 * 522 BC—Babylon rebels against Persian rule.
 * 522 BC—Darius I succeeds Bardiya as ruler of Persia. He is the son of a government official.
 * 521 BC—The Babylonian rebellion against Persian rule is suppressed.
 * 520 BC—Dao becomes King of the Zhou dynasty of China but dies before the end of the year.
 * 520 BC—Cleomenes I succeeds Anaxandridas as king of Sparta (approximate date).
 * c. 520 BC—Darius I decrees that work on Jerusalem resume as per the decree of Cyrus the Great.
 * c. 520 BC—Kore, from Chios(?), is made. It is now at Acropolis Museum, Athens.
 * c. 520 BC—Sarcophagus, from Cerveteri is made. It is now at National Etruscan Museum, Rome (approximate date).
 * 520 BC–510 BC—The Priam Painter makes "Women at a Fountain House", black-figure decoration on a hydria. It is now at Museum of Fine Arts, Boston.

Births

 * 521 BC—Leonidas I. King of Sparta
 * 525 BC—Aeschylus, author of Greek tragedies (d. 456 BC)
 * 522 BC—Pindar, Greek poet
 * 520 BC—Panini, Hindu Indian grammarian (d. 460 BC)

Deaths

 * July, 529 BC—Cyrus the Great, ruler of ancient Persia
 * 528 BC—Anaximenes of Miletus, Greek philosopher (b. 585 BC)
 * 527 BC—Peisistratos, Athenian tyrant
 * 525 BC—Psammetichus III, the last Pharaoh of the Twenty-sixth Dynasty of Egypt
 * 522 BC—Cambyses II, ruler of ancient Persia
 * 522 BC — Polycrates, tyrant of Samos
 * September, 522 BC—Bardiya, ruler of ancient Persia

title: 520s BC


text:
510s BC

This article concerns the period 519 BC – 510 BC.

Events and trends

 * 519 BC—Zhou Jing Wang becomes King of the Zhou Dynasty of China.
 * c. 518 BC—Darius I began construction of Parsa (Persepolis).
 * 518 BC—Construction of Apadana of Darius and Xerxes, ceremonial complex, at Persepolis, Iran started.
 * 516 BC—Indian subcontinent—The occupation of Punjab is completed by the Persian King Darius I.
 * 516 BC—Construction is completed on the Second Temple in Jerusalem.
 * c. 515 BC—Euphronios completes Death of Sarpedon, a red-figure decoration on a calyx krater. Euxitheos is a potter. It is now at The Metropolitan Museum of Art, New York.
 * 514 BC—King Helü of Wu ascends to the throne of Wu in China during the Zhou Dynasty. He established the "Great City of Helu", the ancient name for Suzhou, as his capital.
 * 514 BC—Darius I led his Persian army over the Bosphorus and campaigned unsuccessfully against the Scythians on the Danube.
 * 513 BC—Darius I subdues the Getae and east Thrace in his war against the Scythians.
 * c. 513 BC—Western India becomes the Achaemenid satrapy of Hindush, which included the valley of the Indus River.
 * c. 512 BC—Sun Tzu, author of The Art of War, begins serving Helü of Wu as general and military strategist in the Wu army.
 * 510 BC—Hippias, second son of Pisistratus and tyrant of Athens, is expelled by a popular revolt supported by Cleomenes I, King of Sparta and his forces.
 * 510 BC—End of reign of Lucius Tarquinius Superbus, last king of the traditional seven Kings of Rome.
 * 510 BC—Fall of the Roman Kingdom and establishment of the Roman Republic.
 * 510 BC—Demaratus succeeds Ariston as king of Sparta. (approximate date)
 * 510 BC—Defeat and destruction of Sybaris.
 * c. 510 BC–430 BC—Stelae were banned in Athenian cemeteries.

Births

 * c. 519 BC—Xerxes I of Persia

Deaths

 * King Liao of Wu, China
 * Zhuan Zhu, assassin, China (executed)

title: 510s BC