Followers

Google+ Followers

Monday, May 31, 2010

May 28 - Solar Scientists Agree That the Sun's Recent Behavior Is Odd, but the Explanation Remains Elusive‏

Dear Friends,
Click the link if you can't access the links.
http://www.scientificamerican.com/article.cfm?id=solar-minimum-forecasting
Be Well.
David

Solar Scientists Agree That the Sun's Recent Behavior Is Odd, but the Explanation Remains Elusive

The most recent solar minimum was both long and pronounced. But why?

SDO image of the sun

SOLAR SURPRISES: An image from the new Solar Dynamics Observatory shows activity on the sun's surface; the solar cycle has proved difficult to accurately predict.

MIAMI—In very rough terms, the sun's activity ebbs and flows in an 11-year cycle, with flares, coronal mass ejections and other energetic phenomena peaking at what is called solar maximum and bottoming out at solar minimum. Sunspots, markers of magnetic activity on the sun's surface, provide a visual proxy to mark the cycle's evolution, appearing in droves at maximum and all but disappearing at minimum. But the behavior of our host star is not as predictable as all that—the most recent solar minimum was surprisingly deep and long, finally bottoming out around late 2008 or so.

Solar physicists here at the semiannual meeting of the American Astronomical Society this week offered a number of mechanisms to shed light on what has been happening on the sun of late, but conceded that the final answer—or more likely answers—remains opaque. Beyond scientific understanding, motivations for better solar weather forecasts include hopes to use them to safeguard against electrical grid disruptions, damage to Earth-orbiting satellites and threats to the health of space travelers posed by solar radiation flare-ups.

One researcher has looked for clues to solar weather in the meridional flow, which moves from the solar equator toward the poles, and which seems to change speed during the shifting solar cycle. Another looked at the solar "jet stream," a slow current that originates at solar mid-latitudes and pushes in a bifurcated stream toward both the equator and the poles. Another scientist examined the inner workings of the sun through the oscillation of sound waves propagating through the solar interior; yet another looked at magnetic maps to chart the shifting flux across the sun.

"I think we're almost in violent agreement that this is an interesting minimum," said David Hathaway of the NASA Marshall Space Flight Center in Huntsville, Ala. By several measures—geomagnetic activity, weakness of polar magnetic fields, flagging solar deflection of galactic cosmic rays—the minimum was the deepest on record, Hathaway said, although some of those records contain just a few cycles. Hathaway focused on shifting speeds of the meridional flow, finding that the flow was anomalously fast at the most recent minimum. But, speaking of heliophysics forecasting techniques in general, he cautioned against leaping to any conclusions based on small-number statistics. "We need to be careful about extending what we've seen in one or two cycles to all of them," he said.

Frank Hill of the National Solar Observatory (NSO) instead examined the jet stream, a periodic east–west flow of material that corresponds with the onset and end of the solar cycle. With helioseismology data, which track acoustic oscillations on the sun, researchers can check in on the progress of the jet stream at depths of roughly 1,000 kilometers, potentially allowing for better forecasts of the timing of the solar cycle. But it is "still too early to tell" if the jet stream can robustly predict solar activity, Hill acknowledged, noting that the stream could be a cause or an effect of the cycle.

Hill's NSO colleague Sushanta Tripathy also turned to helioseismology to investigate the recent solar minimum, finding that in acoustic oscillations deep within the sun there were in fact two separate minima—one in late 2007 that did not correspond to the sunspot minimum, and one around late 2008 that did. In prior data, from 1995 to 2007, the frequency shifts in the oscillations had matched up well with the sunspot counts. And at shallower depths within the sun, the seismic and sunspot activity were in phase for the most recent solar minimum as well. All in all, the cycle was definitely unusual, Tripathy said.

Julia Saba of SP Systems, Inc., and the NASA Goddard Space Flight Center in Greenbelt, Md., had yet another approach, turning to magnetic maps to track regional differences on the sun. Her approach accurately forecast the timing of the 2008 solar minimum 18 months in advance, she said, but acknowledged that the forecast had been revised from an earlier prediction. Based on current data, Saba said, the next solar cycle looks like it will be weak and prolonged. But that could all change—her predictions assume "that the sun doesn't change on us again."

After hearing his colleagues' various approaches to investigating the sun's behavior, Hill took stock of a field with many open questions. "My main impression of all this is I'm gratified to see that we all agree that this is an interesting minimum," Hill said. "What's not so gratifying is we have no clue why any of these effects are happening."

No comments:

Post a Comment

esoteric



SUBTITLES IN ENGLISH, ESPAÑOL, PORTUGUÊS

Click upon the circle after the small square for captions

MUFON

How to Digitally Record/Video a UFO sighting:


Como registar digitalmente ou gravar um vídeo de um avistamento de um UFO:




Stabilize the camera on a tripod. If there is no tripod, then set it on top of a stable, flat surface. If that is not possible lean against a wall to stabilize your body and prevent the camera from filming in a shaky, unsteady manner.

Estabilize a camera com um tripé. Se não tiver um tripé, então coloque-a em cima de uma superfície estável. Se não for possível, então encoste-se a uma parede para estabilizar o corpo e evitar que a camera registe de maneira tremida e instável.

Provide visual reference points for comparison. This includes the horizon, treetops, lampposts, houses, and geographical landmarks (i.e., Horsetooth Reservoir, Mt. Adams, etc.) Provide this in the video whenever is appropriate and doesn’t detract from what your focus is, the UFO.

Forneça pontos visuais de referência para comparação. Isso inclui o horizonte, cimo das árvores, postes de iluminação, pontos de referência geográficos (como o Reservatório de Horsetooth, Mone Adams, etc) Forneça esses pontos no vídeo sempre que for apropriado e não se distraia do que é o seu foco, o UFO/a Nave.

Narrate your videotape. Provide details of the date, time, location, and direction (N,S,E,W) you are looking in. Provide your observations on the weather, including approximate temperature, windspeed, any visible cloud cover or noticeable weather anomalies or events. Narrate on the shape, size, color, movements, approximate altitude of the UFO, etc and what it appears to be doing. Also include any unusual physical, psychological or emotional sensations you might have. Narrate any visual reference points on camera so they correlate with what the viewer will see, and thereby will be better able to understand.

Faça a narração do vídeo. Forneça pormenores sobre a data, hora, local e direcção (Norte, Sul, Este, Oeste) que está a observar. Faça observações sobre as condições atmosféricas, incluindo a temperatura aproximada, velocidade do vento, quantidade de nuvens, anomalias ou acontecimentos meteorológicos evidentes. Descreva a forma, o tamanho, a cor, os movimentos, a altitude aproximada onde se encontra o UFO/nave, etc e o que aparenta estar a fazer. Inclua também quaisquer aspectos pouco habituais de sensações físicas, psicológicas ou emocionais que possa ter. Faça a narração de todos os pontos de referência visual que o espectador irá ver e que, deste modo, será capaz de compreender melhor.

Be persistent and consistent. Return to the scene to videotape and record at this same location. If you have been successful once, the UFO sightings may be occurring in this region regularly, perhaps for specific reasons unknown, and you may be successful again. You may also wish to return to the same location at a different time of day (daylight hours) for better orientation and reference. Film just a minute or two under “normal” circumstances for comparison. Write down what you remember immediately after. As soon as you are done recording the experience/event, immediately write down your impressions, memories, thoughts, emotions, etc. so it is on the record in writing. If there were other witnesses, have them independently record their own impressions, thoughts, etc. Include in this exercise any drawings, sketches, or diagrams. Make sure you date and sign your documentation.

Seja persistente e não contraditório. Volte ao local da cena e registe o mesmo local. Se foi bem sucedido uma vez, pode ser que nessa região ocorram avistamentos de UFOs/naves com regularidade, talvez por razões específicas desconhecidas, e talvez possa ser novamente bem sucedido. Pode também desejar voltar ao mesmo lugar a horas diferentes do dia (durante as horas de luz)para ter uma orientação e referência melhor. Filme apenas um ,inuto ou dois em circunstâncias “normais” para ter um termo de comparação. Escreva tudo o que viu imediatamente após o acontecimento. Logo após ter feito o registo da experiência/acontecimento, escreva imediatamente as impressões, memórias, pensamentos, emoções, etc para que fiquem registadas por escrito. Se houver outras testemunhas, peça-lhes para registar independentemente as suas próprias impressões, pensamentos, etc. Inclua quaisquer desenhos, esbolos, diagramas. Certifique-se que data e assina o seu documento/testemunho.

Always be prepared. Have a digital camera or better yet a video camera with you, charged and ready to go, at all times. Make sure you know how to use your camera (and your cell phone video/photo camera) quickly and properly. These events can occur suddenly, unexpectedly, and often quite randomly, so you will need to be prepared.

Esteja sempre preparado, Tenha sempre uma camera digital, melhor ainda, uma camera vídeo consigo, carregada e pronta a usar sempre que necessário. Certifique-se que sabe como lidar com a sua camera (ou com o seu celular/camera fotográfica) rápida e adequadamente. Esses acontecimentos podem acontecer súbita e inesperadamente e, por vezes, acidentalmente, por isso, necessita estar preparado.

Look up. Be prepared. Report. Share.

Olhe para cima, Esteja preparado, Relate, Partilhe.

MUFON.COM

ESOTERIC



Pf., clique no símbolo do YouTube e depois no quadrado pequeno, em baixo, ao lado direito para obter as legendas CC, e escolha PORTUGUÊS

埋め込み画像 4埋め込み画像 5

What time is Around the World?

Translate

AND YOU AND I - click image

JAIL THE BANKERS

ET CONTACT MEDITAWTION

NGC - UFO's in EUROPE (Porugal included)

FEBRUARY 7, 2013 - 7:00PM EST

FEBRUARY 7, 2013 - 7:00PM EST
T O R O N T O