NASA 태양극이동 2013년말쯤 일어날것으로 예측

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Sun's pending magnetic flip has physicists on edge

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The Sun’s magnetic field will soon make a dramatic flip, which it does every 10 to 13 years, and scientists are keeping a close eye to see if that reverses the bizarre behaviour they’ve been seeing for the past decade.

Last week, the sun unleashed the biggest solar flare of the year, an X3.3 flare, which was followed with an only slightly less intense X1 flare from a Jupiter-sized sunspot.

X-class flares are the most powerful class of solar flares, and in late October the sun fired off four in the space of a week.

All indications suggest the sun is ramping up to the midpoint of its solar cycle — which is the peak moment at which it is expected to reverse its magnetic field.

The sun has been behaving particularly strangely since the last time its magnetic field flipped in 2003.

So solar physicists such as Ken Tapping at the National Research Council of Canada are watching carefully.

“As you can imagine, we’re concerned about what’s going to happen next,” said Tapping, who leads a team that monitors the sun’s magnetic activity using a radio telescope in Penticton, B.C.

“Obviously, we would feel happier if we saw the sun doing business as usual, rather than heading off into some territory where we basically are not sure we understand what’s going to happen.”

The sun’s magnetic field is produced by the movement of hot gases as it rotates and as heat rises from the sun’s core to its surface.

Tapping says the magnetic field is what makes the sun appear like a solid sphere rather than a transparent ball of gas: "It changes the fuzzy blob into something that’s more like a block of rubber."

The effects of this magnetic field extend far beyond the planets of the solar system to the edge of interstellar space.

The polarity of the sun’s magnetic field flips every 10 to 13 years, an average of 11 years, marking the peak and midpoint of each solar cycle. The most recent cycle, Solar Cycle 24, started in 2008 and is now approaching its midpoint.

According to NASA, the next flip is expected by the end of the year.

Tapping says the event typically takes one to a few months, and can be observed via the strength of the magnetic field over the sun’s surface — something that the Penticton measurements help calculate.

The beginning of the flip is also marked by the appearance of sunspots at high solar latitudes that are "magnetically the other way round" compared to those at thesun's equator, Tapping said.

Sunspots typically form close to the "poles" of the sun at the beginning of a solar cycle, and gradually move toward the equator over the course of the cycle. The cycles overlap so that sunspots from two cycles typically coexist for a period of time.

Tapping added that the flip will probably have little effect on us humans, other than temporarily increasing the chance of significant solar flares.

Solar flares are eruptions of magnetic energy from the sun’s surface.

If they are directed toward Earth, they can interact with the Earth's magnetic field, knocking out man-made satellites and power grids, affecting navigation equipment on airplanes, and interfering with other electronics and communications systems.

The potential damage to electronic infrastructure on and around Earth are one of the main reasons scientists keep such a close eye on the sun’s magnetic activity.

Around the solar cycle peak and magnetic flip of 2003, the midpoint of Solar Cycle 23, the sun blasted off 17 major eruptions over the space of three weeks, including a record-setting X28 flare.

The resulting geomagnetic storms generated blood-red auroras on Halloween and partially disabled half of NASA's satellite fleet, permanently damaging some satellites.

The rise in powerful solar flares at the peak of a solar cycle is due to the increased complexity of the sun’s magnetic field as it prepares to flip.

While this year's solar storms are far weaker than the ones in 2003, they are "a bigger surprise even as they do less damage," NASA says, since they come at the peak of one of the weakest solar cycles in a century.

The 2003 magnetic flip marked the beginning of some unexpected behaviour. The relationship between two measurements of the sun’s magnetic activity that normally correspond — the magnetic field strength and sunspot counts — started to diverge.

The next solar cycle was supposed to start in 2008, but "things just sat," Tapping said. "And then the next cycle was about two years late in starting."

Since then, it has been a cycle of unusually low magnetic activity.

"When we see the flip and start to get an idea of how activity starts to build up for the next cycle," Tapping said, "I think that will give us an indication of whether the sun will sit there smouldering or whether it's going to come back to usual behaviour."

He noted, however, that usual behaviour is relative term, since scientists have only been monitoring sunspots since the 1700s, and taking more comprehensive measurements of the 4.5-billion-year-old sun since the mid-20th century.

"In all probability," Tapping added. "The sun has done this before."

잦은 x급흑점폭발등 모든태양지표가 태양주기의 중간지점을 향하고 있음을 가르키는데 중간지점에서 태양의 자기장 역전이 있을것으로 예상한다.지난 자기장 역전은 과학자들이 태양주기에 일련번호를 매긴이래 23번째 주기의 중간지점인 2003년에 발생했다 2008년에 23번째 주기가 끝난후 다시 11~13년의 24번째 태양주기가 시작 2013~2014년에 주기의 중간지점에 도달 흑점폭발을 일으키고 태양자기장이 역전될것으로 예측한다 ~~중간생략

싸이클의 중간지점인 정점에서 강한 플레어가 발생하는것은 태양자기극이 역전을 준비하며 자기장의 복잡성이 증가하기때문이다

올해는 2003년에 비하면 흑점폭발 강도가 약한편이다