Автор instml, 08.02.2012 11:43:24
0 Пользователей и 1 гость просматривают эту тему.
ЦитатаComet Lovejoy as seen by the Solar Optical Telescope (SOT) on Hinode as it approached the sun early on 16 December 2011. Hinode purposely adjusted its instruments during this time period to observer the side of the sun and track the comet. Scientists were rewarded with two images, taken 30 seconds apart before Comet Lovejoy vanished into the glare of scattered light from the sun. Using these images, scientists believe the coma -- the visible cloud of ice and dust surrounding the comet -- is about 450 miles across. Since the comet is so much fainter than the sun, the SOT's original image showed a saturated, over bright sun next to the comet; this image has been processed with a replacement, less bright image of the sun that was captured simultaneously. Credit: JAXA/Hinode/LMSAL
ЦитатаIn 2008 in the northern hemisphere of the sun (left) Hinode observed large patches of negative polarity, shown in orange. In 2011, the same area showed much smaller patches and a more even distribution of negative and positive (blue) regions. Credit: JAXA/HinodeApproximately every 11 years the magnetic field on the sun reverses completely - the north magnetic pole switches to south, and vice versa. It's as if a bar magnet slowly lost its magnetic field and regained it in the opposite direction, so the positive side becomes the negative side. But, of course, the sun is not a simple bar magnet and the causes of the switch, not to mention the complex tracery of moving magnetic fields throughout the eleven-year cycle, are not easy to map out.Mapping such fields, however, is a crucial part of understanding how - and, in turn, when - the sun will exercise its next flip. This flip coincides with the greatest solar activity seen on the sun in any given cycle, known as "solar maximum."While the cycle unfolds with seeming regularity every 11 years, in two upcoming papers scientists highlight just how asymmetrical this process actually is. Currently the polarity at the north of the sun appears to have decreased close to zero - that is, it seems to be well into its polar flip from magnetic north to south -- but the polarity at the south is only just beginning to decrease."Right now, there's an imbalance between the north and the south poles," says Jonathan Cirtain, a space scientist at NASA's Marshall Space Flight Center in Huntsville, Ala., who is also NASA's project scientist for a Japanese solar mission called Hinode. "The north is already in transition, well ahead of the south pole, and we don't understand why."One of the two papers relies on Hinode data that shows direct observations of this polar switch. The other paper makes use of a new technique observing microwave radiation from the sun's polar atmosphere to infer the magnetic activity on the surface. The asymmetry described in the papers belies models of the sun that assume that the sun's north and south polarities switch at the same time. In addition, both papers agree that the switch is imminent at the north pole, well in advance of general predictions that solar maximum for this cycle will occur in 2013. Lastly, the direct Hinode results also suggest a need to re-examine certain other solar models as well.Measuring the magnetic activity near the poles isn't easy because all of our solar telescopes view the sun approximately at its equator, offering only an oblique view of the poles, when they require a top-down view for accurate magnetic measurements. Hinode can observe this activity annually with its high resolution Solar Optical Telescope that can map magnetic fields when observing them from near the equator. The microwave radiation technique described in the second paper makes use of the discovery in 2003 that as the sun moves toward solar maximum, giant eruptions on the sun, called prominence eruptions - which during solar minimum, are concentrated at lower solar latitudes -- begin to travel toward higher latitudes near the poles. In addition, the polar brightness in the microwave wavelengths declines to very low values."These prominence eruptions are associated with increased solar activity such as coronal mass ejections or CMEs, so CMEs originating from higher latitudes also point to an oncoming solar maximum," says Nat Gopalswamy. Gopalswamy is a solar scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. who is the first author on the microwave observations paper, which was accepted by The Astrophysical Journal on April 11, 2012. "When we start to see prominence eruptions above 60 degrees latitude on the sun, then we know that we are reaching solar maximum."These images from Hinode show magnetism in the southern hemisphere in 2009 (left) and 2011 (right). The large blue patches show regions of positive polarity, which remain present even in 2011. Credit: JAXA/HinodeTo look at the prominence eruptions toward the poles, Gopalswamy and his team used observations from Japan's Nobeyama Solar Radio Observatory telescopes and the joint ESA/NASA mission the Solar Heliospheric Observatory (SOHO). They watched the sun in the microwave wavelengths - which are used to observe the area of the sun's atmosphere just above the surface, known as the chromosphere. Gopalswamy created precise techniques to use such microwave radiation to measure the intensity of magnetic activity on the sun's surface at the poles. By mapping the brightness of the microwave radiation throughout the chromosphere, the scientists showed that the intensity at the north pole has already dropped to the threshold that was reached in the last solar maximum cycle, suggesting the onset of solar max there. This is backed by the fact that prominence eruptions are also occurring at high latitudes in the north. Eruption activity in the south half of the sun, however, is only just beginning to increase - the first CME occurred there in early March 2012.The Hinode data also shows this discrepancy between the north and the south. The Hinode results are reported by a Japanese team, led by Daikou Shiota a solar scientist at RIKEN Institute of Physics and Chemical Research, and were recently submitted to The Astrophysical Journal for publication. Shiota and his team used Hinode to observe the magnetic map of the poles every month since September of 2008. Early maps showed large, strong concentrations of magnetic fields that are almost all magnetically negative in polarity. Recent maps, however, show a different picture. Not only are the patches of magnetism smaller and weaker, but now there is a great deal of positive polarity visible as well. What once pointed to a strongly negative north pole, is now a weakly magnetized, mixed pole that will become neutral - which occurs at solar maximum -- within the month according to the team's predictions."This is the first direct observation of this field reversal," says Cirtain. "And it is extremely important to understanding how the sun's magnetism generates the solar cycle."Ted Tarbell is the principal investigator for Hinode's Solar Optical Telescope at Lockheed Martin in Palo Alto, Calif., and he points out that the direct measurements showed the progress of the pole reversal, and highlights the earlier portion of the cycle in 2008. Typical models of the magnetic flip, suggest that as active regions rotate around the equator, their higher, trailing edge - which is almost always the opposite polarity from the pole in their hemisphere - drift upward, eventually dominating the status quo and turning positive to negative or negative to positive. The Hinode data show that this transition at the north began before such drifting had a chance to occur."This is one of the most interesting things in this Hinode paper to me," says Tarbell. "How did the polar reversal start so early, even though the onset of the solar cycle, that is, increased activity at lower latitudes, hadn't begun yet?"Tarbell thinks these observations mean that this model, too, may need to be re-examined.Such adjustments to models are of course expected whenever new and better data is collected. Indeed, David Hathaway, who is a solar scientist at NASA's Marshall, and who is a co-author on the microwave observations paper with Gopalswamy, points out that the idea that asymmetries exist in the sun is not completely new. Other work has recently emphasized symptoms of this asymmetry, measuring, for example, more sunspots in the northern hemisphere than in the south at the moment. "But most of the well-developed models don't incorporate the asymmetry in them," Hathaway says. "More complicated models that incorporate asymmetries do exist, but they have other ways in which they fail to match observations."Continued study on these differences, using the best observatories as well as new techniques for analysis will help expand and improve our understanding of the sun, its 11-year cycle, and the great eruptions that occur on its surface.Scientists will also keep their eye on the current cycle - numbered Solar Cycle 24 - because a polar switch at the north that is sooner than was expected also implies this may be a fairly small cycle in terms of the number of sunspots and amount of solar activity.
ЦитатаТОКИО, 23 апреля. /Корр. ИТАР-ТАСС Василий Головнин/. На Солнце в ближайшее время могут образоваться четыре магнитных полюса, что способно вызвать временное похолодание на Земле. С таким прогнозом, как сообщает сегодня токийская печать, выступили японская Национальная обсерватория и Институт естественных наук. Они основываются на длительных наблюдениях, которые ведет за Солнцем спутник "Хинодэ" /"Восход"/.На нашем светиле магнитные полюса обычно меняются местами каждые 11 лет. Как правило, они совпадают при этом с полюсами географическими. Очередной поворот ожидался в мае 2013 года. Однако, судя по всему, на сей раз на северном полюсе Солнца смена минуса на плюс произойдет раньше - уже в нынешнем мае. Не исключено, что южный полюс потом также сменит свой знак на отрицательный. Однако какое- то время оба географических полюса Солнца будут "плюсовыми".По мнению экспертов, в результате в районе экватора там образуются два временных отрицательных магнитных полюса. Такие явления на Солнце происходили и раньше - например, в XVII - XVIII веках. Тогда это совпало с существенным похолоданием на Земле. Японские специалисты полагают, что и нынешнее появление четырех магнитных полюсов на Солнце вызовет временное прекращение неуклонного потепления климата на нашей планете.
ЦитатаAn international research team mainly consisting of researchers from the National Astronomical Observatory of Japan and RIKEN has observed the north and south polar regions of the Sun using JAXA's Solar Physics Satellite "HINODE." As a result, they found that between 2008 and 2012, the reversal from minus to plus polarity of the magnetic field was taking place only in the north polar region, while the magnetic field did not change much in the south polar region.The magnetic field of the solar polar region is known to reverse every 11 years. However, as the reversal occurred only on the north pole, and also with the development of a sunspot that was related to the polar magnetic field reversal, the condition is very similar to the "Mounder Minimum," which brought a cold period to Earth in the mid 17th century. This phenomenon and its further movement need more attention.
ЦитатаHinode captured this image of the January 6, 2011 solar eclipse. Credit: Hinode On May 20-21, 2012 an annular eclipse of the Sun will be visible from within a narrow corridor along Earth's northern Hemisphere -- beginning in eastern Asia, crossing the North Pacific Ocean, and ending in the western United States. A partial eclipse will be visible from a much larger region covering East Asia, North Pacific, North America and Greenland.During an annular eclipse the moon does not block the entirety of the sun, but leaves a bright ring of light visible at the edges. For the May eclipse, the moon will be at the furthest distance from Earth that it ever achieves - meaning that it will block the smallest possible portion of the sun, and leave the largest possible bright ring around the outside.The joint JAXA/NASA Hinode mission will observe the eclipse and provide images and movies that will be available on the NASA website at http://www.nasa.gov/sunearth . Due to Hinode's orbit around the Earth, Hinode will actually observe 4 separate partial eclipses." Scientists often use an eclipse to help calibrate the instruments on the telescope by focusing in on the edge of the moon as it crosses the sun and measuring how sharp it appears in the images. An added bonus: Hinode's X-ray Telescope will be able to provide images of the peaks and valleys of the lunar surface.The orbits for NASA's Solar Dynamics Observatory (SDO), NASA's Solar Terrestrial Relations Observatory (STEREO), and the joint ESA/NASA mission the Solar Heliospheric Observatory will not provide them with a view of the eclipse.The next solar eclipse will be the total solar eclipse on November 13, 2012.More information on eclipses: http://eclipse.gsfc.nasa.gov/eclipse.htmlTo find information about the time of any eclipse in your location: http://eclipse.gsfc.nasa.gov/JSEX/JSEX-index.htmlShare your eclipse photos in our Flickr gallery.
ЦитатаHINODE сфотографировал транзит Венеры из космоса[/size]Астрономы, работающие с японским спутником HINODE, опубликовали фото прохождения Венеры по диску Солнца. Снимки и их описание доступны на сайте NASA. Транзит Венеры (именно так называется произошедшее событие) представляет для ученых значительный интерес. Астрономы используют его для подтверждения тех или иных данных. Первые масштабные наблюдения проводились в 1761 и 1769 годах. Периодичность прохождение Венеры по диску Солнца обусловлено особенностями орбит этой планеты и Земли. Подходящая конфигурация небесных тел случается четырежды в 243 года. Временные промежутки между транзитами составляют 8 лет, 121,5 года, 8 лет и 105,5 года соответственно. HINODE был запущен в космос 23 сентября 2006 года с японского космодрома Утиноура. Основным предназначением космического аппарата является изучение Солнца. Установленные на обсерватории инструменты позволяют спутнику наблюдать за солнечной короной, а также измерять скорость и направление солнечного ветра. В апреле 2009 года HINODE участвовал в исследовании Солнца, проводимом Японским космическим агентством совместно с Россией. Тогда спутник совместно с отечественным "Коронас-ФОТОН" сделал несколько десятков тысяч синхронных снимков светила, которые, среди прочего, позволили получить представления о трехмерной структуре корональных выбросов.