史丹佛大學的威考太陽觀測站，由美國太空總署（NASA）與美國國家科學基金會等單位贊助，專門研究太陽對地球的影響及宇宙氣候。威考觀測站自1975年就開始觀測太陽的磁力現象，是全球少數幾個嚴密監控太陽磁場轉換的觀測站。對於磁場翻轉的現象，站長陶德‧霍克斯瑪解釋，太陽是一顆活生生的天體，有著頻繁且猛烈的活動，其噴發出的高能粒子太陽風能影響地球磁極與大氣層。太陽黑子的物理活動如閃焰、爆發日珥與日冕物質噴發等，在太陽黑子活動達到高峰期時，都會變得比平常更加頻繁和活躍。
當每11年太陽星體的物理活動達到高峰期時，就會造成磁場反轉。原本應是磁N極的太陽北極、磁S極的太陽南極，此時會反轉成北極為磁S極、南極為磁N極。如此一來，將會在太陽表面引起壯闊波瀾，甚至會影響整個太陽系的磁場。史丹佛大學的太陽物理學家費爾薛表示，一般而言，在磁場反轉的瞬間，太陽兩極磁場的力量會同時削弱，近乎消失，接著隨即又以相反磁極出現。
霍克斯瑪說，目前太陽活動頻繁，先前已有許多科學家發現太陽磁場轉換的徵兆，但今年卻出現一些不尋常的現象。《國家地理雜誌》報導，根據威考觀測站的資料，今年太陽南北半球的磁極不同步，南半球比北半球慢半拍。當北半球的磁極轉換到南半球，但南半球的磁極慢一步時，就會有兩個磁極同時出現在南極的現象發生。但科學家表示，目前南半球磁極正在努力趕上，很快太陽磁極就會開始逆轉，大約3、4個月就會翻轉完全。隨著磁場逆轉，太陽赤道外輻射狀的曲流層會開始波動，根據美國《太空網》指出，NASA官員表示，地球環繞太陽運行時，會進入取流層的波動處然後離開，而這段期間將在地球附近形成暴風雨。除此之外，太陽磁極改變也將影響地球的磁極與洋流，恐將造成氣候異常。
威考太陽觀測站今年首次將歷年的統計資料彙整到網路上。費爾薛表示，威考觀測站是全世界唯一擁有如此豐富太陽磁場資料的觀測站，能夠將累積了40年的數據與一般民眾分享，站內的科學家們都感到很興奮。圖說：太陽物理活動高峰期會造成閃焰、爆發日珥與日冕物質噴發，最後將產生磁場反轉的現象。
Sun Will Flip Its Magnetic Field Soon
Editor's Note: See our update on what the sun's magnetic flip means for Earth here: Sun's Magnetic Field Flip Won't Doom Earth, Scientists SayThe sun is gearing up for a major solar flip, NASA says.
In an event that occurs once every 11 years, the magnetic field of the sun will change its polarity in a matter of months, according new observations by NASA-supported observatories.
The flipping of the sun's magnetic field marks the peak of the star's 11-year solar cycle and the halfway point in the sun's "solar maximum" — the peak of its solar weather cycle. NASA released a new video describing the sun's magnetic flip on Monday (Aug. 5).
"It looks like we're no more than three to four months away from a complete field reversal," Todd Hoeksema, the director of Stanford University's Wilcox Solar Observatory, said in a statement. "This change will have ripple effects throughout the solar system."
As the field shifts, the "current sheet" — a surface that radiates billions of kilometers outward from the sun's equator — becomes very wavy, NASA officials said. Earth orbits the sun, dipping in and out of the waves of the current sheet. The transition from a wave to a dip can create stormy space weather around Earth, NASA officials said.
The sun's magnetic field is gearing up to shift, a once in 11 year event, according to NASA officials.Credit: NASA
"The sun's polar magnetic fields weaken, go to zero, and then emerge again with the opposite polarity," Stanford solar physicist Phil Scherrer said in a statement. "This is a regular part of the solar cycle."
While the polarity shift can stir up some stormy weather, it also provides extra shielding from dangerous cosmic rays. These high-energy particles, which are accelerated by events like supernova explosions, zip through the universe at nearly the speed of light. They can harm satellites and astronauts in space, and the wrinkled current sheet better protects the planet from these particles.
The effects of the rippled sheet can also be felt throughout the solar system, far beyond Pluto and even touching the Voyager probes near the barrier of interstellar space.
"The sun's north pole has already changed sign, while the south pole is racing to catch up," Scherrer said. "Soon, however, both poles will be reversed, and the second half of solar max will be underway."
The current solar maximum is the weakest in 100 years, experts have said. Usually, at the height of a solar cycle, sunspot activity increases. These dark regions on the sun's surface can give birth to solar flares and ejections, but there have been fewer observed sunspots this year than in the maximums of previous cycles.
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