Solar poles to become quadrupolar in May
The Yomiuri Shimbun
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.
When a similar phenomenon occurred about 300 years ago, the Earth’s average temperature fell slightly.
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 researchers also found the magnetic field at the South Pole, which was expected to reverse along with the North Pole, maintained a positive polarity, ensuring the formation of a quadrupole magnetic field.
The cause behind the shifts in polar fields is not understood. However, it is known that the shifts coincide with the increase and decrease in the number of sunspots over an about 11-year cycle.
The current sunspot cycle has stretched for close to 13 years. A similar situation occurred in the 17th to 18th century, when the average temperature of the Northern Hemisphere decreased by 0.6 C. The research team believes the quadrupolar pattern also emerged at that time.
According to U.S. clocks, May 5, 2012 features the closest and largest full moon of this year. Calendars say May 6, by the way, for this same close full moon as seen from Europe, the Middle East, Africa and Asia. We astronomers call this sort of close full moon a perigee full moon. The word perigee describes the moon’s closest point to Earth for a given month. But last year, when the closest and largest full moon occurred on March 19, 2011, many used a term we’d never heard: supermoon. We’ll probably hear that term again at this 2012 close full moon. What does it mean exactly? And how special is it?