Meteorologia Espacial - Seguimento 2007

Luis França

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Claro que sim. Este ano acabámos de sair do mínimo solar, por isso agora vamos entrar num máximo solar até 2011-2012. Até lá o Árctico derrete como prevêem num estudo recente. Alguém duvida disso? :lmao:
 

Luis França

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Ainda este ano o Sol pode reservar-nos alguma surpresa no sapatinho. Porquê? Porque este mês tem tido anomalias muito pouco vulgares. já é 3ª vez que a sua superfície fica anormalmente "escura", como na seguinte imagem, e agora parece que a sua rotação abrandou pois neste link verificarão que as sunpots mal mudaram de posição. Ou sou eu que estou a precisar de lentes novas?

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Minho

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Ainda este ano o Sol pode reservar-nos alguma surpresa no sapatinho. Porquê? Porque este mês tem tido anomalias muito pouco vulgares. já é 3ª vez que a sua superfície fica anormalmente "escura", como na seguinte imagem, e agora parece que a sua rotação abrandou pois neste link verificarão que as sunpots mal mudaram de posição. Ou sou eu que estou a precisar de lentes novas?


Quem pode precisar de umas lentes novas é o SOHO, ou substituir os sensores CCD's ou corrigir algum bug no software que produz estas lindas imagens do Sol. Desde que a luz do Sol entra na lente do SOHO até chegar às nossas casas sofre inúmeros tratamentos, conversões, correcções, etc... O facto de uma imagem estar mais escura ou clara nada tem a ver com a luminosidade do Sol...
 

Luis França

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Pois. Se reparares na sequência indicada no link verás a descontinuidade entre o antes e o depois; porque é que aquele fotograma aparece mais escuro? Assim como em séries anteriores, se calhar tenho de colocar os gráficos e tabelas para se ver essa descontinuidade...

Era óptimo que não passasse nada de grave com o nosso querido Sol. :)


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Vince

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Pois. Se reparares na sequência indicada no link verás a descontinuidade entre o antes e o depois; porque é que aquele fotograma aparece mais escuro? Assim como em séries anteriores, se calhar tenho de colocar os gráficos e tabelas para se ver essa descontinuidade...
Era óptimo que não passasse nada de grave com o nosso querido Sol. :)

Luis, as imagens do observatório SOHO (e outros) são matéria prima frequente para todo o tipo de especulações. Qualquer interferência nos sensores, na transmissão de dados ou no software de tratamento de imagens aparece logo nos sites do costume: Ovnis, Teorias alternativas, da Conspiração, Cataclismos, Esotérico e Divino, etc,etc. E também explicam como as pessoas que alimentam esse tipo de especulações pegam nas imagens com defeito e "douram" a pilula com variados efeitos em photoshop.

No próprio site do SOHO até tens informação sobre esse tipo de erros, por exemplo aqui está um texto divertido, e sobretudo didático, sobre como fabricar um Ovni a partir de uma imagem com defeito, e de como uma fabricação deste género até foi parar aos jornais.

How to Make Your Own UFO

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ORIGINAL
Cut-out of EIT 195 image from 2001/01/18 at 16:24 UT, taken from the public SOHO archive, with standard processing & color table. The circle highlights a cosmic ray hit


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STEP 1:
Further cut-out, showing the cosmic ray pixels highlighed on the image to the left, with a little different color scaling.


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STEP 2:
Still the same data, but interpolated (using one of a zillion possible methods) instead of simply resampled as the previous one.

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STEP 3:
Voila! Finally, after a "touch-up" of the color table, we have what may look like a nice UFO with a glow and exhaust fumes!

See how the same image, having gone through a strikingly similar "enhancement" is used to "prove" the existence of UFOs, in pitches resulting in e.g. this newspaper article (Perth Sunday Times (Australia), 2003/01/19, p. 44). Yes, this was a picture from SOHO, but didn't show any UFO! We believe similar "enhancements", possibly starting with other types of image artifacts (see below for details), are behind all of the recently published "UFO proof" claims. Claims without the time and date of the picture are close to worthless, because the data processing cannot be verified by others.

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Caption:

Ever since launch, there's been a number of people who've claimed to have seen flying saucers and other esoteric objects in SOHO images. Although some of these supposed pictures of UFOs can seem quite intriguing, they have always turned out to have a quite ordinary cause when examined by experienced SOHO scientists. In recent days, we've been receiving so many questions and claims that we'd like to set the record straight: We've never seen anything that even suggests that there are UFOs "out there".

In the past we've been accused of "covering up" UFO evidence when we present our explanations, and of "refusing to comment" (or "clamming up") when we give up on somebody who won't accept our explanations. While we don't expect to convince everybody, we hope that this page (and links herein) can provide some information for the curious who want to investigate the claims on their own.

Most commonly, UFO claims are due to perfectly natural flaws or artifacts in our publicly available data. Quoting from one of the replies sent by a SOHO scientist in response to a question from the public:

The most common sources of UFO claims are:

* Planets: These always look very strange in LASCO images, because they're so bright that the image blooms, and the CCD pixels bleed along the readout rows. Some people try to claim that they're flying saucers, based on their appearance. I've also heard the claim that they're previously unknown Saturn-like planets with rings around them. You can see what I'm talking about on this SOHO Hot Shot page.

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* Cosmic rays: High energy particles from the solar wind, and from the galaxy as a whole, whip around the SOHO spacecraft and interact with the detectors. These produce spots and streaks on the detector ranging from a single pixel, to large streaks that span a large fraction of the image. These are most evident during a solar storm, as can be seen on this Hot Shot page, but are always present at some level. I know that some people have claimed that they've seen spacecraft-looking things that seem to be moving around, but which are obviously cosmic rays when examined by an experienced observer. People see a cosmic ray at one location in one image, and then another random cosmic ray hit nearby in the next image, and claim they're both the same thing moving between frames.

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Sometimes you'll see a cosmic ray seem to persist in the web images for two or more frames. This is because we lose a certain percentage of the data coming down from the spacecraft. In LASCO such losses appear as square blocks in the image. The software which puts the images up on the web will fill in these blocks from the last good image, and if there's a cosmic ray in that block from the previous image, it will appear in this image as well. The way to check for this is to look at the raw data files, which are also available on the web through the SOHO catalog interface.


* Software glitches: Occasionally we'll have some problems with the software which produce the images for the web, and strange artifacts will appear in the data. These glitches are usually corrected within a few days. In fact, we had a couple of instances of that recently.

* Detector defects: There are defects which appear in the cameras from time to time, sometimes temporary and sometimes permanent. I remember seeing a web site which claimed that strange lights were hovering over the lower left limb of the Sun in EIT images, and thought to myself "You only just noticed that?". Those defects have been around forever, and were seen in the lab even before SOHO was launched.

Debris: Small pieces of aging insulation on the outside of the spacecraft, dust particles, micrometeorites etc can show up in pictures. Visit the LASCO Debris Lists and Images page for more details.

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On the general subject of UFO claims from SOHO images, one should be aware that a lot of the supposed UFO pictures taken by SOHO have been modified by the proponents. For example, looking at the image that is distributed with the news release for the upcoming UFO conference, it's obvious that the picture is taken from a tiny number of pixels in the camera, and then passed through some kind of smoothing filter to make it look like a craft with rounded edges. They should at least have the courage to show the actual data, and not something which has been manipulated in Photoshop. In the example above, where the original image was "revealed" through the timestamp, we have shown how easy it can be to manipulate pictures into showing UFO-like features.

That all said, it should be noted that we do see objects moving in SOHO images. Over 500 comets have been discovered in SOHO images, most by amateurs using LASCO data which have been downloaded from the web. That's more comets than from any other observatory, either from the ground or in space. People are looking for moving objects in these pictures all the time, and are highly motivated to find them. None of them have ever turned out to be anything other than comets.More about comets observed by SOHO on this SOHO Hot Shot page.

http://sohowww.nascom.nasa.gov/hotshots/2003_01_17/
(c) SOHO
 

Luis França

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Óptimo fiquei perfeitamente elucidado quanto a essas dúvidas. Tomara que sim, que seja só isso. Pena é nunca sabermos a verdade.

Que tenhamos um Natal bem gélido graças ao aquecimento global e que o Sol esteja de perfeita saúde para nos aquecermos quando precisarmos.
 

Vince

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Óptimo fiquei perfeitamente elucidado quanto a essas dúvidas. Tomara que sim, que seja só isso. Pena é nunca sabermos a verdade.

Se alguém estivesse a esconder alguma coisa nem sequer disponibilizariam as imagens :p
Uma alteração do brilho do sol dessa ordem se fosse real e não um erro do sensor ou do software seria um evento catastrófico e a esta hora já nem sequer estariamos aqui a falar.
 

Luis França

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Imagens da SOHO/NASA do último ciclo solar

The Solar and Heliospheric Observatory (SOHO) celebrates its 12th launch anniversary on December 2. In late 1996, shortly after its launch, SOHO was able to observe the last minimum of the roughly 11-year activity cycle of the Sun. The minimum was followed by a rapid rise in solar activity, peaking 2001 and 2002. Activity levels have slowly declined since then, but we haven't reached solar minimum yet, despite passing 11.1 years since the last minimum — the average length of a solar cycle.

In fact, the sunspot cycles measured since the mid-18th century vary in length from 9.0 to 13.5 years, and while a team of experts assembled by NOAA, NASA, and ISES has attempted to predict when the next solar minimum will be, we won't really know until we get there. The experts, in fact, were sharply divided about the time of the next minimum and the intensity of the next maximum, which should arrive about 2012 or 2013.
Whenever the next cycle begins, SOHO will be there to observe it.


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Luis França

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The geomagnetic field is expected to be quiet to major storm on December 17 and quiet to active on December 18-22 due to effects from CH304.
Latest Alert: December 17 1602 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected.
AURORA WATCH: Sky watchers, be alert for auroras. Earth is entering a solar wind stream and this is causing high-latitude geomagnetic storms.

Ora nem mais. Vamos ter animação geomagnética a acompanhar a situação meteorológica de 18 a 22 Dezembro, mesmo nas vésperas da conjunção.

The party is about to begin... :malandro::assobio::bombar:
 

Luis França

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O Sol hoje esteve bem forte (em termos de densidade) mas já voltou ao normal. Irá começar o novo ciclo solar?

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"The average density of the solar wind at 1 AU is about 7 protons/cm^3 with large variations. The solar wind confines the magnetic field of Earth and governs phenomena such as geomagnetic storms and aurorae. The solar wind confines the magnetic fields of other planets as well.

The heliosphere is the immense magnetic bubble containing our solar system, solar wind, and the entire solar magnetic field. It extends well beyond the orbit of Pluto. While the density of particles in the heliosphere is very low (it's a much better vacuum than is created in a laboratory), it is full of particles of interest to heliospheric scientists. Check out the image below for a diagram of the heliosphere.

More about the Sun's magnetic field...

The solar wind near our Sun's surface contains alternating streams of high and low speed. These streams corotate with the Sun, that is, they rotate along with it. The high-speed streams originate in coronal holes and extend toward the solar poles; the low-speed streams come from near the Sun's equator. There are compositional differences between the high and low speed streams of the solar wind.

With increasing distance from the Sun, the high-speed streams overtake the slower plasma, producing corotating interaction regions (CIRs) on their leading edges. CIRs are bounded by two shocks at the front and rear edges called the forward and reverse shocks. At these shocks, the density, pressure, and magnetic field strength are all higher. These regions are quite effective as energetic particle accelerators. When ions that have been accelerated at a CIR are observed, they are called corotating ion events.

Energetic storm particles (ESPs), accelerated by shocks associated with solar flares and CMEs, are another example of interplanetary acceleration.

The heliopause is the name for the blurred boundary between the heliosphere and the interstellar gas outside the solar system. As the solar wind approaches the heliopause, it slows suddenly, forming a shock wave. This solar wind termination shock is exceptionally good at accelerating particles."

[link to helios.gsfc.nasa.gov]