The kelvin is the base unit of temperature in the International System of Units, having the unit symbol K. It is named after the Belfast-born, Glasgow University engineer and physicist William Thomson, 1st Baron Kelvin; the kelvin is now defined by fixing the numerical value of the Boltzmann constant k to 1.380 649×10−23 J⋅K−1. This unit is equal to kg⋅m2⋅s−2⋅K−1, where the kilogram and second are defined in terms of the Planck constant, the speed of light, the duration of the caesium-133 ground-state hyperfine transition. Thus, this definition depends only on universal constants, not on any physical artifacts as practiced such as the International Prototype of the Kilogram, whose mass diverged over time from the original value. One kelvin is equal to a change in the thermodynamic temperature T that results in a change of thermal energy kT by 1.380 649×10−23 J. The Kelvin scale fulfills Thomson's requirements as an absolute thermodynamic temperature scale, it uses absolute zero as its null point.

Unlike the degree Fahrenheit and degree Celsius, the kelvin is not referred to or written as a degree. The kelvin is the primary unit of temperature measurement in the physical sciences, but is used in conjunction with the degree Celsius, which has the same magnitude. In 1848, William Thomson, created Lord Kelvin, wrote in his paper, On an Absolute Thermometric Scale, of the need for a scale whereby "infinite cold" was the scale's null point, which used the degree Celsius for its unit increment. Kelvin calculated; this absolute scale is known today as the Kelvin thermodynamic temperature scale. Kelvin's value of "−273" was the negative reciprocal of 0.00366—the accepted expansion coefficient of gas per degree Celsius relative to the ice point, giving a remarkable consistency to the accepted value. In 1954, Resolution 3 of the 10th General Conference on Weights and Measures gave the Kelvin scale its modern definition by designating the triple point of water as its second defining point and assigned its temperature to 273.16 kelvins.

In 1967/1968, Resolution 3 of the 13th CGPM renamed the unit increment of thermodynamic temperature "kelvin", symbol K, replacing "degree Kelvin", symbol °K. Furthermore, feeling it useful to more explicitly define the magnitude of the unit increment, the 13th CGPM held in Resolution 4 that "The kelvin, unit of thermodynamic temperature, is equal to the fraction 1/273.16 of the thermodynamic temperature of the triple point of water."In 2005, the Comité International des Poids et Mesures, a committee of the CGPM, affirmed that for the purposes of delineating the temperature of the triple point of water, the definition of the Kelvin thermodynamic temperature scale would refer to water having an isotopic composition specified as Vienna Standard Mean Ocean Water. On 16 November 2018, a new definition was adopted, in terms of a fixed value of the Boltzmann constant. With this change the triple point of water became an empirically determined value of 273.16 kelvin. For legal metrology purposes, the new definition came into force on 20 May 2019, the 144th anniversary of the Metre Convention.

According to the International Bureau of Weights and Measures, when spelled out or spoken, the unit is pluralised using the same grammatical rules as for other SI units such as the volt or ohm. When reference is made to the "Kelvin scale", the word "kelvin"—which is a noun—functions adjectivally to modify the noun "scale" and is capitalized; as with most other SI unit symbols there is a space between the kelvin symbol. Before the 13th CGPM in 1967–1968, the unit kelvin was called a "degree", the same as with the other temperature scales at the time, it was distinguished from the other scales with either the adjective suffix "Kelvin" or with "absolute" and its symbol was °K. The latter term, the unit's official name from 1948 until 1954, was ambiguous since it could be interpreted as referring to the Rankine scale. Before the 13th CGPM, the plural form was "degrees absolute"; the 13th CGPM changed the unit name to "kelvin". The omission of "degree" indicates that it is not relative to an arbitrary reference point like the Celsius and Fahrenheit scales, but rather an absolute unit of measure which can be manipulated algebraically.

In science and engineering, degrees Celsius and kelvins are used in the same article, where absolute temperatures are given in degrees Celsius, but temperature intervals are given in kelvins. E.g. "its measured value was 0.01028 °C with an uncertainty of 60 µK". This practice is permissible because the degree Celsius is a special name for the kelvin for use in expressing relative temperatures, the magnitude of the degree Celsius is equal to that of the kelvin. Notwithstanding that the official endorsement provided by Resolution 3 of the 13th CGPM states "a temperature interval may be expressed in degrees Celsius", the practice of using both °C and K is widespread throughout the scientific world; the use of SI prefixed forms of the degree Celsius to express a temperature interval has not been adopted. In 2005 t

Templebryan Stone Circle is a stone circle, located 2.5 km north of Clonakilty, County Cork, Ireland. Grid ref: W386 438. Close by lies an Early Christian site; the stone circle is a 9.5m wide axial stone circle. It consisted of nine large flat topped standing stones; these include the axial-stone and one of the portal stones, 210 cm high. A large block of quartz lying in the circle centre is known locally as Cloich Griene. All four remaining standing stones are in the eastern half of the circle, including one that may be a portal stone, it is not known how many made up the circle, but in 1743 nine stones were still standing, although by 1837 only the five stones seen today remained. About 300m north-west is an enclosure containing graves, a square ruined oratory, a souterrain, a well, a bullaun, a monolith 3.3m high with faint Ogham inscriptions. These were carved on the existing standing stone and may have had some connection with the stone circle. There is a small cross pattee inscribed on the western side of this Bronze Age megalith.

The single bullaun is known locally as the ` wart well'. List of megalithic monuments in Cork Megalithics - Templebryan Recumbent Stone Circle - Co. Cork Megalithomania - Templebryan Stone Circle

Thomas Weldon Anderson known as Thomas Weldon Atherstone, was an English music hall star and victim of an unsolved murder. His body was found in an empty London apartment on 16 July 1910. Atherstone was born Thomas Weldon Anderson in Liverpool in 1862, he was a classically trained actor who became prominent in music halls during the early 1880s and 1890s, although by the turn of the century his presence in vaudeville had been reduced with the exception of occasional performances, such as poetry readings. Although married with four children, he began living with actress Elizabeth Earle at an apartment in London's Battersea district around 1899. While Atherstone's career continued declining over the next decade, Earle retired from the music hall and turned to teaching, he and Earle began arguing regarding his accusations of Earle carrying on an affair as well as his resentment towards her success as a professional schoolteacher. Earle sent him to live with his two sons Thomas Frederick and William Gordon.

Earle remained on friendly terms with the son Thomas and when visiting her one evening for supper they heard gunshots from the yard downstairs. Thomas investigated and saw the body of a man, violently shot to death. After calling for the police, it was discovered to be the body of Atherstone. Although an investigation found several witnesses who claimed to have seen a man jumping over a back wall fleeing the scene, police believed Atherstone had been spying on the two when he encountered a burglar who shot him and fled the scene. However, the murder remains unsolved. Whittington-Egan, Richard. Mr Atherstone Leaves the Stage... The Battersea Murder Mystery: A Twisting and Tragic Tale of Love and Violence in the age of Vaudeville London: Amberley Publishing, 2015. Macnaghten, Sir Melville Leslie. Days of My Years. London: Edward Arnold, 1914