GREAT BALL OF FIRE!From about 150 million km (93 million mi) away, the sun provides light and heat that are essential to our survival. That's why it's crucial to know how the sun works, how it evolves and changes, and how it affects us here on Earth. With the help of the Solar and Heliospheric Observatory The Solar and Heliospheric Observatory (SOHO) is a spacecraft that was launched on an Atlas IIAS launch vehicle on 2 December 1995 to study the Sun, and began normal operations in May 1996. (SOHO Soho (sōhō`, sə–), district of Westminster, London, England, known for its continental restaurants. Once a fashionable quarter, it became popular among writers and artists in the 19th cent. ), a satellite built specifically to study the sun, scientists have uncovered some of the sun's best-kept secrets. Rivers of Fire Scientists have discovered "rivers" of hot flowing plasma, or electrically charged gas, rushing beneath the sun's surface near the poles. These rivers surge at about 1,400 km/h (880 mph)--about 130 km/h (80 mph) faster than surrounding gases. Sun Belts Similar to Earth's trade winds, bands of plasma loop around the sun at different speeds relative to each other. The faster-moving belts measure more than 64,000 km (40,000 mi) across and move about 16 km/h (10 mph) faster than their surroundings. Scientists suspect that this difference in speeds may generate solar magnetic activity that produces sunspots sunspots, dark, usually irregularly shaped spots on the sun's surface that are actually solar magnetic storms. The Chinese recorded dark features on the sun seen with the naked eye in 28 B.C. and solar flares solar flare Sudden intense brightening of a small part of the Sun's surface, often near a sunspot group. Flares develop in a few minutes and may last several hours, releasing intense X rays and streams of energetic particles. . Fast-moving Equator Gases at the sun's equator rotate at a faster rate than those near the poles, circling the sun in about 25 days. The poles take more than a month to complete a rotation. SOLAR MAGNET The sun's 11-year cycle is driven by its magnetic field. 1 At the beginning of the solar cycle solar cycle Period in which several important kinds of solar activity repeat, discovered in 1843 by Samuel Heinrich Schwabe (1789–1875). Lasting about 22 years on average, it includes two 11-year cycles of sunspots, whose magnetic polarities alternate between the , the sun's magnetic field lines run directly from one pole to the other. 2 The sun's equator, which moves faster than the poles, tugs at each field line and pulls it out of shape. 3 By the cycle's peak, the constant pulling and stretching leaves the field lines all tangled up. Spiraling solar gases, however, bring together field lines of the same magnetic orientation. This realignment re·a·lign tr.v. re·a·ligned, re·a·lign·ing, re·a·ligns 1. To put back into proper order or alignment. 2. To make new groupings of or working arrangements between. eventually puts the magnetic field lines back in order. |
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