Operation Sigma Sigma

The Sigma is an experimental glider developed in Britain from 1966 by a team led by Nicholas Goodhart. After disappointing performance during flight testing the Sigma was passed on to a Canadian group which carried out modifications, making the Sigma more competitive.

Design and development

Designed to compete in the 1970 World Championships, the team aimed to develop a wing that would climb well through a high lift coefficient and a large wing area, but equally had the "maximum possible reduction of area for cruise at low lift coefficients". At the same time for the minimum possible drag they aimed for "extensive" laminar flow. To achieve this they employed flaps that would alter both wing area and wing camber. Based on analysis of the nature of thermals encountered in cross-country flying, they reasoned that by having a slow turning circle, their sailplane could stay close to the central (and strongest) part of the thermal and gain maximum benefit.

Its unusual feature is its ability to vary its wing area using Fowler flaps. It had been tried before by the Hannover Akaflieg in 1938 with their AFH-4, the South African Beatty-Johl BJ-2 Assegai and the SZD Zefir gliders.

Sigma (cosmology)

Sigma in cosmology was a property of galaxies used when trying to work out the mystery of galaxies and their supermassive black holes.

History

In the late 1990s the NUKER experts had made observations with a spectroscope of two galaxies, one of an active galaxy with an active galactic nucleus called NGC10-68 and a dormant galaxy next door to us named Andromeda.

The observations are shown. The light from the centre in Andromeda galaxy was distorted proving the existence of super-massive black holes.

Other observations proved most galaxies had a similar centre whether it be active or dormant.

They then realised that the black holes must have something to do with a galaxy's formation, so they turned to something they thought was useless: the speed of the stars around the edge of the galaxy. This was Sigma, the speed of the stars at the edge of the galaxy supposedly unaffected by the mass of the black hole at the centre.

Usage In Cosmology

The NUKER team calculated the sigma of several stars in different galaxies and the mass of the black hole at the (nucleus) centre. They expected no correlation what so ever. But when plotting their results on a Scatter diagram and drawing a line of best fit they ended up with a positive correlation. It appeared that the heavier the black hole at the centre was the faster the stars within the galaxy travelled.

Sigma (duo)

Sigma is an English drum and bass duo consisting of Cameron Edwards and Joe Lenzie. They met at Leeds University at drum and bass nights. Their 2010 collaboration with DJ Fresh, "Lassitude", peaked at number 98 on the UK Singles Chart. Their single "Nobody to Love" topped the UK Singles Chart, becoming their first UK number one. Follow-up single "Changing", featuring Paloma Faith, also got to number one.

Career

Formation

Lenzie and Edwards met in 2006 at Leeds University; Cameron was working in local record store Tribe Records and with Echo Location's Obi running local night Event Horizon, while Lenzie was DJing hip-hop and warming up Event Horizon for such acts as Rahzel and Grandmaster Flash. Once they had finished in Leeds, they relocated to London and became a three-piece with Edwards' school friend Ben Mauerhoff, being signed under DJ Fresh's Breakbeat Kaos. After a while, long distances took their toll – Edwards and Mauerhoff were based in Surrey, whereas Lenzie was based in Harpenden, Hertfordshire and they couldn't get three people into the Harpenden studio – and Mauerhoff left. In December 2008 they formed their own record label, Life Recordings (so called because, according to Lenzie, the industry demanded that it be their life). Its inaugural release was a VIP mix of their early Bingo Beats single "El Presidente".

Asteroid

Asteroids are minor planets, especially those of the inner Solar System. The larger ones have also been called planetoids. These terms have historically been applied to any astronomical object orbiting the Sun that did not show the disc of a planet and was not observed to have the characteristics of an active comet. As minor planets in the outer Solar System were discovered and found to have volatile-based surfaces that resemble those of comets, they were often distinguished from asteroids of the asteroid belt. In this article, the term "asteroid" refers to the minor planets of the inner Solar System including those in co-orbit with Jupiter.

There are millions of asteroids, many thought to be the shattered remnants of planetesimals, bodies within the young Sun's solar nebula that never grew large enough to become planets. The large majority of known asteroids orbit in the asteroid belt between the orbits of Mars and Jupiter, or are co-orbital with Jupiter (the Jupiter trojans). However, other orbital families exist with significant populations, including the near-Earth asteroids. Individual asteroids are classified by their characteristic spectra, with the majority falling into three main groups: C-type, M-type, and S-type. These were named after and are generally identified with carbon-rich, metallic, and silicate (stony) compositions, respectively.

Asteroids (video game)

Asteroids is an arcade space shooter released in November 1979 by Atari, Inc. and designed by Lyle Rains, Ed Logg, and Dominic Walsh. The player controls a spaceship in an asteroid field which is periodically traversed by flying saucers. The object of the game is to shoot and destroy asteroids and saucers while not colliding with either or being hit by the saucers' counter-fire. The game becomes harder as the number of asteroids increases.

Asteroids was one of the first major hits of the golden age of arcade games. The game sold over 70,000 arcade cabinets and proved both popular with players and influential with developers. It has since been ported to multiple platforms. Asteroids was widely imitated and directly influenced two popular and often cloned arcade games, Defender and Gravitar, as well as many other video games.

Asteroids was conceived during a meeting between Logg and Rains and used hardware developed by Howard Delman previously used for Lunar Lander. Based on an unfinished game titled Cosmos and inspired by Spacewar! and Computer Space, both early shoot 'em up video games, Asteroids' physics model and control scheme were derived by Logg from these earlier games and refined through trial and error. The game is rendered on a vector display in a two-dimensional view that wraps around in both screen axes.