Solar cycle

The solar cycle or solar magnetic activity cycle is the nearly periodic 11-year change in the Sun's activity (including changes in the levels of solar radiation and ejection of solar material) and appearance (changes in the number of sunspots, flares, and other manifestations).

They have been observed (by changes in the sun's appearance and by changes seen on Earth, such as auroras) for centuries.

The changes on the sun cause effects in space, in the atmosphere, and on Earth's surface. While it is the dominant variable in solar activity, aperiodic fluctuations also occur.

Definition

Solar cycles have an average duration of about 11 years. Solar maximum and solar minimum refer respectively to periods of maximum and minimum sunspot counts. Cycles span from one minimum to the next.

Observational history

The solar cycle was discovered in 1843 by Samuel Heinrich Schwabe, who after 17 years of observations noticed a periodic variation in the average number of sunspots.Rudolf Wolf compiled and studied these and other observations, reconstructing the cycle back to 1745, eventually pushing these reconstructions to the earliest observations of sunspots by Galileo and contemporaries in the early seventeenth century.

Quiet Sun

Quiet Sun were an English progressive rock/jazz fusion band from the Canterbury Scene consisting of Phil Manzanera (guitars), Bill MacCormick (bass), Dave Jarrett (keyboards) and Charles Hayward (drums).

History

Having originated from a Dulwich College band by the name of Pooh and the Ostrich Feather, Quiet Sun was formed in 1970 after MacCormick had made friends with Robert Wyatt, the son of a friend of his mother's. The band integrated jazz elements and sparkling keyboard sounds into their complex music - similar to Soft Machine - but Manzanera's energetic guitar made their music very different from the Softs' who had not been using any guitar (other than bass guitar) on their regular albums before the 1975 release of Bundles, and had used reeds as the main other melody instruments aside from keyboards.

Quiet Sun split up in 1972, Manzanera to Roxy Music, MacCormick to Matching Mole, Hayward to This Heat, and Jarrett began to teach mathematics.

In 1975, Manzanera booked a studio for 26 days to record his album Diamond Head and got Quiet Sun together again to record an album from their old composed material in the studio at the same time. This first and only album of theirs, with participation of Brian Eno and the late Ian MacCormick, titled Mainstream was critically acclaimed and became the New Musical Express' album of the month. One of Quiet Sun's songs appears on Robert Wyatt's Ruth Is Stranger Than Richard, under the name "Team Spirit". Additionally, reworked versions of "Rongwrong" and "Mummy was an asteroid, Daddy was a small non-stick kitchen utensil" both appear on the album 801 Live (the latter is consolidated with a track from Diamond Head, "East of Echo", with the result titled "East of Asteroid").