Tau (sculpture)

American sculptor Tony Smith designed "“Tau”" in the early 1960s. It is 14’ high x 12’ wide x 12’ deep, and made from black painted steel. Its title refers to the Greek letter 'T', which also describes the shape of the sculpture. Fascinated by mathematics, biology and crystals, Smith designed Tau with geometry at its root. There are two extant versions of the large sculpture: Tau (AP), and Tau (1/3).

Description

Many of Smith's sculptures were made up of a space lattice: groupings of simple platonic solids, in Tau's case two such solids, octahedrons and tetrahedrons. The original model for the sculpture was created by Smith in 1961-62 using his signature process of joining small cardboard tetrahedrons, a process he began while recuperating after a severe automobile accident in the spring of 1961.

During this period, Smith was transitioning from his 20-year career in architecture to focus on painting and making sculptures. Smith had also started teaching at Hunter College, New York, in 1962. It took over 20 years for the piece to be installed outside the upper east side college at the 6 train's 68th Street entrance in 1984. In 2004, Hunter College held an exhibition, "Tracing Tau", curated by William C. Agee that offered an insight into the sculpture and its beginnings through paper models, drawings and plans of the work.

Pi

The number π is a mathematical constant, the ratio of a circle's circumference to its diameter, commonly approximated as 3.14159. It has been represented by the Greek letter "π" since the mid-18th century, though it is also sometimes spelled out as "pi" (/paɪ/).

Being an irrational number, π cannot be expressed exactly as a fraction (equivalently, its decimal representation never ends and never settles into a permanent repeating pattern). Still, fractions such as 22/7 and other rational numbers are commonly used to approximate π. The digits appear to be randomly distributed; however, to date, no proof of this has been discovered. Also, π is a transcendental number – a number that is not the root of any non-zero polynomial having rational coefficients. This transcendence of π implies that it is impossible to solve the ancient challenge of squaring the circle with a compass and straightedge.

Ancient civilizations needed the value of π to be computed accurately for practical reasons. It was calculated to seven digits, using geometrical techniques, in Chinese mathematics and to about five in Indian mathematics in the 5th century CE. The historically first exact formula for π, based on infinite series, was not available until a millennium later, when in the 14th century the Madhava–Leibniz series was discovered in Indian mathematics. In the 20th and 21st centuries, mathematicians and computer scientists discovered new approaches that, when combined with increasing computational power, extended the decimal representation of π to, as of 2015, over 13.3 trillion (10¹³) digits. Practically all scientific applications require no more than a few hundred digits of π, and many substantially fewer, so the primary motivation for these computations is the human desire to break records. However, the extensive calculations involved have been used to test supercomputers and high-precision multiplication algorithms.

Tau (particle)

The tau (τ), also called the tau lepton, tau particle, or tauon, is an elementary particle similar to the electron, with negative electric charge and a spin of ¹⁄₂. Together with the electron, the muon, and the three neutrinos, it is a lepton. Like all elementary particles with half-integral spin, the tau has a corresponding antiparticle of opposite charge but equal mass and spin, which in the tau's case is the antitau (also called the positive tau). Tau particles are denoted by τ− and the antitau by τ+.

Tau leptons have a lifetime of 6987290000000000000♠2.9×10⁻¹³ s and a mass of 7003177682000000000♠1776.82 MeV/c² (compared to 7002105700000000000♠105.7 MeV/c² for muons and 6999511000000000000♠0.511 MeV/c² for electrons). Since their interactions are very similar to those of the electron, a tau can be thought of as a much heavier version of the electron. Because of their greater mass, tau particles do not emit as much bremsstrahlung radiation as electrons; consequently they are potentially highly penetrating, much more so than electrons. However, because of their short lifetime, the range of the tau is mainly set by their decay length, which is too small for bremsstrahlung to be noticeable: their penetrating power appears only at ultra high energy (above PeV energies).

Main

Main may refer to:

Geography

People and organisations

Ocean

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Main (river)

The Main (German pronunciation: [ˈmaɪn]) is a river in Germany. With a length of 527 km (327 mi) (including the White Main: 574 km (357 mi)), it is the longest right tributary of the Rhine, and the longest river lying entirely in Germany (if we consider the Weser and the Werra as two separate rivers; together they are longer). The largest cities along the Main are Frankfurt am Main and Würzburg.

Geography

The Main River flows through the German states of Bavaria, Baden-Württemberg (forming the border with Bavaria for some distance) and Hesse. Its basin competes with the Danube for water; as a result, many of its boundaries are identical with those of the European Watershed.

The Main begins near Kulmbach in Franconia at the joining of its two headstreams, the Red Main (Roter Main) and the White Main (Weißer Main). The Red Main originates in the Franconian Jura mountain range, 50 km (31 mi) in length, and runs through Creussen and Bayreuth. The White Main originates in the mountains of the Fichtelgebirge; it is 41 km (25 mi) long. In its upper and middle section it runs through the valleys of the German Highlands. Its lower section crosses the Lower Main Lowlands (Hanau-Seligenstadt Basin and northern Upper Rhine Plain) to Wiesbaden, where it discharges into the Rhine. Major tributaries of the Main are the Regnitz, the Franconian Saale, the Tauber, and the Nidda.

Main (surname)

Main as a surname may refer to

See also