Unusual magnetic changes in the Sun - The north pole of the Sun had started flipping about a year earlier than expected
While scientists had predicted that the next flip would begin from May 2013, the solar observation satellite Hinode found that the north pole of the sun had started flipping about a year earlier than expected. There was no noticeable change in the south pole.
The researchers found signs of unusual magnetic changes in the sun. Normally, the sun’s magnetic field flips about once every 11 years. In 2001, the sun’s magnetic north pole, which was in the northern hemisphere, flipped to the south. If that trend continues, magnetic field polarity at the solar poles will reverse and become quadrupolar in May, meaning positive fields will emerge in the North and South poles and negative fields will emerge on the equator, according to the National Astronomical Observatory of Japan and other institutes. A research team led by Saku Tsuneta, a professor at the observatory, analyzed solar magnetic fields data using Hinode, an observational satellite, and confirmed that the polarity of the magnetic field at the North Pole began to reverse in July last year.
The research team believes the quadrupolar pattern also emerged in the 17th to 18th century. The Japanese study found that the trend of current sunspot activity is similar to records from Maunder Minimum, period about 300 years ago when temperatures are estimated to have been about 2.5 degrees lower than in the second half of the 20th century. Officials of the National Astronomical Observatory of Japan and the Riken research foundation said on April 19 that the activity of sunspots appeared to resemble a 70-year period in the 17th century in which London’s Thames froze over and cherry blossoms bloomed later than usual in Kyoto.
The Sun's PolesLike Earth, the Sun has a North Pole, a South Pole, and an equator. The poles of the Sun are different in several ways from the areas near the Sun's equator. About every 11 years, the Sun's magnetic poles flip - North becomes South and vice versa. This flip happens around the peak of the sunspot cycle, when there are lots of sunspots. Earth's magnetic poles sometimes flip, too. However, it is usually many thousands or even millions of years between flips of Earth's field - not just 11 years! The last polar reversal occurred around 750,000 years ago, but it can happen at shorter intervals, depending on prevailing circumstances. Some researchers think our planet is overdue for another one, but nobody knows exactly when the next reversal might occur. Many scientists, including Einstein, have predicted that another polar shift is close at hand. Several ancient civilisations have left records predicting global devastation and change. The Hopi Indian and Mayan calendars have predicted global devastation and an era of change starting in the year 2012.
The ongoing changes are not confined to the space immediately around our star, Hathaway added. The Sun's magnetic field envelops the entire solar system in a bubble that scientists call the "heliosphere." The heliosphere extends 50 to 100 astronomical units (AU) beyond the orbit of Pluto. Inside it is the solar system - outside is interstellar space.
Sunspots are places on the "surface" of the Sun where the magnetic field is much, much stronger than normal. Sunspots only appear near the Sun's equator, between about 40° North and 40° South latitude. Sunspots never appear near the Sun's poles. Some parts of the Sun rotate more slowly than other parts. At the equator, the Sun spins pretty fast. It takes 25 days to turn all the way around. It turns more slowly at the poles. The poles take 34 days to spin around once. The Sun's atmosphere at the poles is also different from the atmosphere above the Sun's equator. The corona, part of the Sun's atmosphere, sticks out further from the Sun's surface near the equator. The corona doesn't stick out as far above the poles. The solar wind is also different at the poles. It "blows" much faster above the poles than it does above the Sun's equator.
The Sun's magnetic fieldThe Sun has a very large and very complex magnetic field. The magnetic field at an average place on the Sun is around 1 Gauss, about twice as strong as the average field on the surface of Earth (around 0.5 Gauss). Since the Sun's surface is more than 12,000 times larger than Earth's, the overall influence of the Sun's magnetic field is vast. The magnetic field of the Sun actually extends far out into space, beyond the furthest planet. This distant extension of the Sun's magnetic field is called the Interplanetary Magnetic Field (IMF). The solar wind, the stream of charged particles that flows outward from the Sun, carries the IMF to the planets and beyond. The solar wind and IMF interact with planetary magnetic fields in complex ways, generating phenomena such as the aurora.
Places where the Sun's magnetic field is especially strong are called active regions, and often produce telltale sunspots. The local magnetic field in the neighborhood of a large sunspot can be as strong as 4,000 Gauss... much, much greater than the Sun's average field. Disruptions in magnetic fields near active regions can spawn energetic explosions on the Sun such as solar flares and Coronal Mass Ejections (CME). The degree of complexity of the Sun's field waxes and wanes over the course of each sunspot cycle.
The exact nature and source of the Sun's magnetic field are areas of ongoing research. Turbulent motions of charged plasmas in the Sun's convective zone clearly play a role. Some of the Sun's magnetism may even be a remnant from the primordial cloud from which the Sun formed. Some of the spectacular structures seen in the solar atmosphere, such as solar prominences and coronal loops, are fantastic visible indicators of material flowing along magnetic field lines which arc thousands of kilometers above the Sun's surface.
HinodeHinode project is exploring the magnetic fields of the Sun, and is improving our understanding of the mechanisms that power the solar atmosphere and drive solar eruptions. Solar-B, now named Hinode (Sunrise), was successfully launched from Japan's Uchinoura Space Center. (Click HERE for RealVideo or HERE for Windows Media)
The Hinode mission is a follow-on to the highly successful Japan/US/UK Yohkoh (Solar-A) satellite which operated between 1991 and 2001. Led by the Japanese Aerospace Exploration Agency's (JAXA) Space Science Research Division (formerly the Institute of Space and Astronautical Science (ISAS)), Hinode consists of a coordinated set of optical, EUV, and X-ray instruments that will investigate the interaction between the Sun's magnetic field and its corona. The result will be an improved understanding of the mechanisms that power the solar atmosphere and drive solar eruptions. This information will tell us much about how the Sun generates magnetic disturbances and high-energy particle storms that propagate from the Sun to the Earth and beyond; in this sense, Hinode will help us predict "space weather."
Hinode (Solar-B) has been placed in a sun-synchronous orbit around Earth at an altitude of about 600 km. A sun-synchronous orbit is a special type of polar orbit in which a satellite passes over the same part of the Earth at roughly the same local time each day.