terça-feira, 29 de janeiro de 2008

Participação de Fábio Carvalho em trabalho sobre tempestades em Júpiter




28/01/2008 - 08h43 - Folha de São Paulo

Tempestades varrem Júpiter e mudam a face do planeta


IGOR ZOLNERKEVIC
Colaboração para a Folha de S.Paulo

Quando estiver preso em um engarrafamento causado pelas chuvas, relaxe.


Olhe para o céu e pense:


"Podia ser dez vezes pior, podia ser uma tempestade monstro de Júpiter".


Ano passado, nuvens tempestuosas com mais de 100 km de altura varreram o planeta Júpiter, dando uma retocada em seu famoso visual de faixas coloridas.


Uma equipe internacional de 25 astrônomos profissionais e amadores, incluindo um brasileiro, observou duas dessas tempestades tingir de vermelho uma faixa branca no hemisfério norte do maior planeta do sistema solar.


Fotos tiradas no início de 2007 no quintal de casa por Fábio Carvalho, de São Carlos (SP), e por mais dois astrônomos amadores na Austrália, chamaram a atenção de pesquisadores que consultavam na internet os arquivos de associações internacionais de astrofotógrafos.


Eles notaram o que parecia o topo redondo de uma coluna de nuvens brancas tempestuosas crescendo e emergindo, como um cogumelo de bomba atômica, acima da eterna cobertura jupiteriana de nuvens em redemoinhos.


Em 25 de março de 2007, nove horas depois do telescópio espacial Hubble começar a monitorar a tempestade em Júpiter, outra coluna surgiu na mesma região do planeta.

As duas se formaram na crista da corrente de ar mais veloz de Júpiter, situada no meio de seu hemisfério norte.

Em pouco mais de um dia atingiram 2.000 km de extensão, e mais tarde cobriam uma área maior do que a da Lua.

Elas circundaram Júpiter a uma velocidade de 600km/h, deixando um rastro rubro de turbulência que coloriu a faixa branca.


Durante mais de 45 dias, astrônomos amadores em vários países ajudaram a acompanhar o movimento das duas tempestades, complementando as observações pontuais do Hubble e do Telescópio Infravermelho da Nasa, no Havaí.


A análise dessas observações, publicada na revista científica "Nature" da semana passada, ajuda a entender melhor ventos fortes e estreitos chamados de correntes de jatos, que circulam tanto na alta atmosfera de Júpiter quanto na terrestre.

"Em Júpiter, há 16 desses jatos que, ninguém sabe como, criam o padrão de faixas coloridas do planeta", explica Augustín Sánchez-Lavega, da Universidade do País Basco, Espanha, principal autor do estudo.


Planeta azul


Na Terra, há apenas dois jatos, um em cada hemisfério.

Eles serpenteiam constantemente ao redor do globo a uma altura de mais ou menos 12 km.

Suas freqüentes mudanças influenciam o tempo em todo o planeta.

"Muitas entradas de frentes frias em São Paulo são causadas por variações nas correntes de jato", diz o meteorologista Amauri de Oliveira, da Universidade de São Paulo, que não participou da pesquisa.


Os jatos de Júpiter, pelo contrário, são quase retos e mudam pouco. Muito raramente --como foi observado em 1975, 1990 e agora em 2007--, duas tempestades brotam do pico dos jatos e perturbam os céus do planeta.

"Parece um fenômeno periódico, algo surpreendente em uma atmosfera turbulenta e caótica como a de Júpiter", diz Sánchez-Lavega.


O estudo dele indica que as tempestades se formam quando uma coluna de 120 km de nuvens sobe 30 km acima do topo da cobertura normal de nuvens da atmosfera de Júpiter.

Essas nuvens trazem à tona cristais de gelo de água, amônia e sulfidrato de amônio, que em contato com a luz do sol deixam o ar avermelhado.


Essas nuvens sobem movidas pelo calor produzido no interior de Júpiter, concluíram os pesquisadores.

Ao contrário da Terra, onde a força de ventos e chuvas vem do calor do Sol, acredita-se que a principal fonte de energia da circulação atmosférica em Júpiter é o calor produzido quando o seu núcleo de hidrogênio líquido e metálico encolhe, comprimido pelo próprio peso.

O planeta é essencialmente uma bola de gás 1.300 vezes maior que a Terra, mas que diminui de tamanho mais ou menos 3 cm todo ano.


"Nós examinamos só o creme por cima de um bolo de informações", diz Glenn Orton, do Laboratório de Propulsão a Jato da NASA, co-autor do estudo.

A campanha de observações de 2007 coincidiu com a passagem por Júpiter da sonda New Horizons da Nasa, em sua jornada rumo a Plutão.

A New Horizons fotografou de perto tempestades estranhas no hemisfério sul que os pesquisadores também estão analisando.

Outros trabalhos fotográficos de Fábio Carvalho em



Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com



http://br.groups.yahoo.com/group/Observatorio_Monoceros/





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Los perdurables misterios del Sistema Solar exterior

24-Jan-2008

Los perdurables misterios del Sistema Solar exterior


En los últimos confines de nuestro Sistema Solar permanecen algunas de las áreas más misteriosas alrededor del Sol.

Resolver estos misterios del Sistema Solar exterior podría arrojar luz sobre cómo surgió el sistema, así como la vida en la Tierra.

¿Por qué ese arco iris de colores en el cinturón de Kuiper?

Por ejemplo, el cinturón de Kuiper, más allá de Neptuno, se sospecha que sea la casa de los cometas que sólo necesitan unas décadas, o como mucho siglos, para completar sus órbitas solares, los llamados "cometas de período corto". Sorprendentemente, los objetos del cinturón de Kuiper "muestran un amplio rango de colores, neutros o incluso ligeramente azules siguiendo todo el camino hasta el rojo intenso", dijo el astrofísico de la Universidad de Hawai David Jewitt.

El color de un objeto ayuda a revelar detalles sobre la composición de su superficie. Aún es un misterio el por qué los objetos del cinturón de Kuiper muestran un rango más amplio de colores, y por tanto de composiciones de superficie, que otros planetoides, tales como los asteroides.
Algunos investigadores han sugerido que la actividad volcánica podría haber llevado a esos colores, "absurdo en el contexto de cuerpos de 100 kilómetros de tamaño", dijo Jewitt, ya que el vulcanismo necesita algo más grande.

Jewitt y sus colegas han sugerido que los rayos cósmicos podrían haber creado los objetos del cinturón de Kuiper más rojos, mientras que los impactos con otras rocas podrían haber dejado al descubierto materia más prístina que los hace menos rojos. Hoy día Jewitt cree que debe haber otra explicación para este arco iris, pero permanece desconocida.

¿Qué es la materia ultrarroja?

Parece existir un material conocido como "materia ultrarroja" que aparece sólo en aproximadamente la mitad de todos los objetos del cinturón de Kuiper y su progenie inmediata, conocidos como centauros, helados planetoides que orbitan entre Júpiter y Neptuno que escaparon muy recientemente del cinturón de Kuiper.

Esta materia ultrarroja no existe en el Sistema Solar interior, "ni siquiera en los cometas que proceden del cinturón de Kuiper. Esto sugiere que la materia ultrarroja es de alguna forma inestable a las altas temperaturas cerca del sol", explicó Jewitt.

Los colores rojos sugieren que esta sustancia podría contener moléculas orgánicas. Es común la idea de que cometas y otros planetoides han ayudado a traer moléculas orgánicas a la Tierra.

"En los objetos del cinturón de Kuiper, los componentes orgánicos podrían haber sido "cocinados" por la radiación de los rayos cósmicos, dándoles esas superficies de color rojo oscuro, pero no hay prueba de ello", dijo Jewitt. Idealmente una nave podría ir allí y descubrirlo, añadió.



¿Ha menguado el cinturón de Kuiper?

Los cálculos teóricos sugieren que el cinturón de Kuiper estuvo en una época cientos o incluso miles de veces más poblado de lo que está ahora. "¿Cómo se perdió el 99 por ciento o 99,9 por ciento de la masa, y cuándo?", preguntó Jewitt.

Una conjetura sugiere que cuando Saturno y Júpiter desplazaron sus órbitas hace aproximadamente 4 mil millones de años, su tirón gravitatorio lanzó los objetos del cinturón de Kuiper fuera del Sistema Solar. Otros dicen que los objetos del cinturón de Kuiper se pulverizaron, y el polvo fue barrido por la radiación del Sol. Otra posibilidad "es que estemos pasando por alto algo crucial y la conclusión de que el cinturón está en su mayor parte vacío sea incorrecta", dijo Jewitt. "Todas estas posibilidades son igualmente difíciles de asumir, pero serían sorprendentes de ser ciertas".

¿Secretos en la nube de Oort?

Una reserva distante de billones de comentas conocida como la nube de Oort podría estar a más de 100.000 unidades astronómicas del Sol, (una unidad astronómica o UA son aproximadamente 150 millones de kilómetros). Esto significa que la nube de Oort está a un quinto de la distancia de la estrella más cercana, tan lejana que los objetos dentro de ella nunca se han observado de forma directa, sólo inferido, pero deben existir, dados todos los cometas vistos a lo largo de los años.

Se conjetura que la nube de Oort es la fuente de los cometas que necesitan siglos o milenios para completar su recorrido a lo largo del Sol. Dado que estos "cometas de período largo" proceden de todas las direcciones, se piensa a menudo que la nube de Oort es esférica. No obstante, aunque los cometas como el Halley no proceden del cinturón de Kuiper, sus órbitas tampoco encajan con una nube de Oort esférica, explicó Jewitt. Esto sugiere que puede haber una "nube de Oort interior" con una forma similar a la de una rosquilla.

Los astrofísicos piensan que la nube de Oort es un remanente del disco protoplanetario que se formó alrededor del Sol aproximadamente hace 4.600 millones de años. Aprender más sobre la nube de Oort arrojaría luz sobre cómo nació nuestro Sistema Solar ( y la Tierra), dijo Jewitt.

¿Existen más planetas enanos?

Hasta ahora, se han reconocido tres planetas-enanos; Ceres, Plutón y Eris. El cinturón de Kuiper, que yace aproximadamente a 50 UA del Sol, podría albergar 200 o más. Más allá podría haber registros de cuerpos del tamaño de planetas-enanos aproximadamente a 100 UA del Sol "que nadie ha visto antes debido a su débil brillo y movimiento lento", dijo el astrónomo Chad Trujillo del Observatorio Gemini en Hawai. "Incluso un cuerpo tan grande como Marte podría pasar desapercibido a nuestras actuales investigaciones si se moviese más allá de un par de cientos de UA".

Trujillo apunta que proyectos como Pan-STARRS (Telescopio de Investigación Panorámica y Sistema de Respuesta Rápida) y el LSST (Gran Telescopio de Investigación Sinóptica) "deberían llenar estos huecos de nuestro conocimiento en la próxima década".

¿De dónde vinieron los planetas enanos?

Existen teorías sobre que los planetas-enanos del Sistema Solar exterior pudieron haber vivido en el Sistema Solar interior hace miles de millones de años, basándonos en las actuales trayectorias orbitales. Si es así, "¿por qué hay tanto hielo en sus superficies?", pregunta Trujillo. Se espera que los cuerpos del Sistema Solar interior pierdan su hielo debido a la luz solar.

Trujillo y sus colegas sospechan que el hielo que vemos ahora en estos planetas enanos es relativamente nuevo, con dicho reemplazo de hielo procedente tal vez de dentro de estos mundos, en erupciones de "criovulcanismo". Por supuesto, se necesita más investigación para ver si dicha renovación del hielo es suficiente para cubrir al planeta enano después de que viajase del Sistema Solar interior al exterior, añadió.

¿Los rayos cósmicos proceden de una burbuja alrededor del Sistema Solar?

Cuando el viento supersónico de partículas cargadas que fluye desde nuestro Sol, colisiona con el fino gas que se encuentra entre las estrellas, el viento solar básicamente infla una burbuja en este medio interestelar, una bola conocida como heliósfera.

Los científicos han pensado que los inusualmente débiles rayos cósmicos (partículas de energía que vuelan a toda velocidad del espacio a la Tierra), proceden de la heliósfera. Específicamente, se cree que estos rayos proceden del "choque de terminación", una onda de choque de partículas calientes comprimidas que resulta del frenazo abrupto del viento solar contra el gas interestelar. (El choque de terminación parece estar a aproximadamente entre 75 y 85 UA del Sol).

Sin embargo, la Voyager 1 no vio ningún signo de que estos anómalos rayos cósmicos se produjesen en el choque de terminación. "Tal vez no cruzó el choque en el lugar o momento adecuado", dijo el astrofísico del MIT John Richardson, o tal vez la visión estándar de cómo se generan estos rayos cósmicos anómalos es incorrecta. La Voyager 2 cruzó el choque de terminación en 2007 aproximadamente a 1.600 millones de kilómetros de distancia de donde lo hizo la Voyager 1 en 2004, y sus datos, que aún están siendo analizados, "pueden ayudarnos a comprender dónde se producen estas partículas", explicó.

"Se ha informado que los rayos cósmicos afectan al clima de la Tierra por lo que comprender su origen es importante", añadió Richardson. Además, las partículas de alta de energía de estas ondas de choque disparadas por las enormes erupciones solares conocidas como eyecciones de masa coronal (CME) pueden dañar a naves y astronautas, y comprender mejor el choque de terminación podría ayudar a comprender mejor estas otras partículas potencialmente peligrosas.



Crédito de la imagen: Don Dixon/cosmographica.com, Universidad de Arizona.

Traducido y editado por el equipo de Astroseti.
Colaboradores:
- Manuel Hermán Capitán
- Xavier Civit






Posted by:

-------------------------------------------------------------------------
Lucimary Vargas de Oliveira Guardamino Espinoza

Além Paraíba-MG-Brasil
Presidente:
Observatório Astronômico Monoceros

Estacão Meteorológica Nº083/5ºDISME-INMET
CEPESLE -Centro de Estudos e Pesquisas Sertões do Leste
AHAP-Arquivo Histórico de Além Paraíba
http://www.monoceros.xpg.com.br/
http://astronomicando.blogspot.com/
http://arqueoastronomy.blogspot.com/
http://www.arquivohistorico-mg.com.br/
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MSN: observatoriomonoceros@hotmail.com
--------------------------------------------------------------------------

Lançamentos Russos e Europeus até 2009


Olá!

O calendário de lançamentos dos vaivéns espaciais foi actualizado. Assim, o
calendário que havia enviado anteriormente para a lista deverá ser
actualizado para o seguinte (na seguinte lista só estão incluídos os voos
russos e europeus até 2009):

05 Fevereiro - Progress M-63
07 Fevereiro - Atlantis STS-122 / ISS-1E Columbus
22 Fevereiro - ATV-1 'Jules Verne'
13 Março - Endeavour STS-123 / ISS-1J/A Kibo
08 Abril - Soyuz TMA-12
24 Abril - Discovery STS-124 / ISS-1J
14 Maio - Progress M-64
05 Setembro - Atlantis STS-125 HSM-SM-04
12 Agosto - Progress M-65
11 Setembro - Progress M-66
12 Outubro - Soyuz TMA-13
16 Outubro - Endeavour STS-126 / ISS-ULF-2
26 Novembro - Progress M-67
04 Dezembro - Discovery STS-119 / ISS-15A
2009
10 Fevereiro - Progress M-68
25 Março - Soyuz TMA-14
23 Abril - Endeavour STS-127 / ISS-2J/A
?? Maio - Soyuz TMA-15
16 Julho - Atlantis STS-128
?? Agosto - Soyuz TMA-16
03 Setembro - Discovery STS-129
22 Outubro - Endeavour STS-130
?? Novembro - Soyuz TMA-17
2010
21 Janeiro - Atlantis STS-131
18 Março - Discovery STS-132
29 Abril - Endeavour STS-133

Abraço!

Rui C. Barbosa
www.zenite.nu/orbita
http://www.carris-geres.blogspot.com/
Braga - Portugal


-----------------------------------
Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com

Celestial orchestra

A rare quartet of stars may unlock secrets of stellar evolution.

Provided by the University of Hawaii

Artist's view of the gaseous disk that may have once engulfed and maneuvered the quadruple stellar system into its unusually small orbit. Institute for Astronomy/University of Hawaii [View Larger Image]
January 14, 2008
Astronomers using telescopes on Mauna Kea have found an extremely rare quartet of stars that orbit each other within a region smaller than Jupiter's orbit around the Sun. The quartet appears as a speck of light even when viewed with the world's most powerful telescopes, but its spectrum reveals not one, but four distinct stars arranged in two pairs. Astronomers are now struggling to work out whether they could have been born that way, or were forced together by a dense disk of gas in their youth.

This discovery of the star, called BD -22º5866, is really a very rare system of four closely orbiting stars. The findings were announced by Dr. Evgenya Shkolnik of the University of Hawaii's Institute for Astronomy and the NASA Astrobiology Institute on January 8, 2008, at the annual meeting of the American Astronomical Society in Austin, TX. She and collaborators Dr. Michael C. Liu, also of the University of Hawaii, and Dr. I. Neill Reid of the Space Telescope Science Institute in Baltimore were monitoring several hundred nearby low-mass stars when one observation caught their attention because it was unlike anything they had seen before.

At the time of the observations, two of the stars were orbiting each other at 133 km/s (300,000 mph, a speed that would get you from Honolulu to New York in less than a minute), while the second pair moved at a more modest speed of 52 km/s (120,000 mph). Using these speeds and the stars' masses, astronomers were able to determine the maximum sizes of their oddly tight orbits. Less than 1 in 2,000 stars observed might be such tightly bound systems, making this quadruple stellar system extremely rare.

This image shows a to-scale schematic of the quadruple stellar system overlayed for comparison with a diagram of the solar system's planetary orbits. Evgenya Shkolnik [View Larger Image]
The first pair orbits each other in less than 5 days with the orbit's radius of at most 0.06 AU (where 1 AU is the distance from Earth to the Sun). The second pair orbits with a period of less than 55 days and a maximum radius of 0.26 AU. The two pairs are orbiting each other with a maximum radius of only 5.8 AU, an orbital period of less than 9 years, about the same as Jupiter's distance from the Sun.

"The extraordinarily tight configuration of this stellar system tells us that there may have been a single gaseous disk that forced them into such small orbits within the first 100,000 years of their evolution, as the stars could not have formed so close to one another. This is the first evidence of a disk completely encompassing four stars," says Dr. Shkolnik. "It is remarkable how much a single stellar spectrum can tell us about both the present and the past of these stars."

The data were acquired at the Keck I 10-m (33-foot) telescope and on the Canada-France-Hawaii 3.6-m (12-foot) telescope, both located on the summit of Mauna Kea, a 14,000-foot-high dormant volcano on the Big Island of Hawaii. Each telescope is equipped with a high-resolution spectrograph, an instrument capable of breaking up the star's light into different colors (or wavelengths), known as a spectrum.

The stellar system is 51 pc (or 166 light-years) away from the Sun and lies just south of the constellation Aquarius (The Water Bearer). Though BD -22º5866 cannot be seen without a telescope, it is relatively bright and will be carefully monitored to map the orbits in more detail. Since most stars form as part of a binary- or multiple-star system, the enormous potential of this quadruple system to give us previously unavailable physical information makes it a key to unlocking a few mysteries of stellar evolution.

Fonte: Original desta notícia pode ser acessada através do site: http://www.gea.org.br/mss.html
Céu claro para todos!
José Geraldo Mattos - Moderador
"A desarmonia do universo é a mais perfeita criação; não foi e jamais será imitada pelo gênio humano" - (Prof. A. Seixas Neto)
Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com

Monster Black Holes Soon to Collide?

Imagine a binary system consisting of two monstrous black holes locked in a tight orbital embrace. One of the beasts contains an astonishing 100 million times the mass of our Sun, outweighing the Milky Way's central black hole by a factor of 25. But compared to its master, it's a pipsqueak — a pathetic excuse for a black hole.
OJ 287
Active galaxy OJ 287 in Cancer is thought to have two supermassive black holes in its nucleus, one of them possibly the most massive such object known in the universe. In the model pictured here, flares occur when the smaller black hole plunges through a disk of gas around the larger one twice during each 12-year orbit.

Not to scale. In reality the large hole is 170 times the diameter of the small one, and even the large one (700 a.u. wide) is about the size of a pixel at the scale of their separation here.
S&T: Gregg Dinderman
The primary black hole contains 17 or 18 billion solar masses, making it the heaviest single object known to science.

An international team led by Mauri J. Valtonen (University of Turku, Finland) not only claims that such a system exists, but that the team has measured a decay in the period of the binary's 12-year, highly elongated orbit. As Valtonen and his colleagues reported at last week's American Astronomical Society meeting in Austin, Texas, the two black holes are drawing slowly but inexorably nearer during each orbital passage as they radiate gravitational waves, ripples in the fabric of space-time predicted by Einstein's general theory of relativity.

If their analysis is correct, the system, located in the active galaxy OJ 287, contains one of the most massive black holes in the universe and is the most extreme binary system ever discovered. Moreover, OJ 287 presents scientists with an extraordinary opportunity to test Einstein's greatest theory in the strongest gravitational fields the universe has to offer.

"I'd like it to be true, since it would be a tremendously exciting discovery," says Cole Miller (University of Maryland). "But there are observational and theoretical reasons to be skeptical."

Valtonen and his colleagues are hinging their conclusion on a series of optical outbursts, or pulses, that seem to repeat every 12 years, but with a shrinking time interval between each outburst. These pulses, argues the team, occur when the smaller black hole plunges into a gaseous disk that feeds the larger black hole. Last year the team predicted that OJ 287's next outburst would occur within one or two days of September 13, 2007. Valtonen organized an observing campaign among 30 professional and amateur astronomers in 10 nations. The group saw OJ 287 flare exactly on cue.

"The size of the outburst was predicted theoretically, as well as its 4-day length," says Valtonen. He adds that the polarization of the light also disappeared, as his group's model predicts. If the orbit were not shrinking due to gravitational waves, the outburst would have occurred about 20 days later. "It would be a huge coincidence to have all of these observations fit our model by chance," says Valtonen. "There is no other explanation except for Einstein's theory. The timing of the outbursts shows that Einstein's theory is correct to the 10% level."

OJ 287, located 3 billion light-years from Earth in Cancer, has been monitored since the 1890s. The observations show sporadic outbursts, but their frequency doesn't match up perfectly with a 12-year orbit. "The time separation increased from the 1970s to the 80s and 90s," says Tod Strohmayer (NASA/Goddard Space Flight Center). "That appears to me to be opposite to what one would expect if the orbit were shrinking, in which case the period should show a regular decrease. In order to explain these variations," says Strohmayer, "they need very fast precession of the orbit, and the only way to explain that in the context of their model is to invoke a problematically high black hole mass. I think they are over-interpreting the data."

Miller adds that OJ 287 belongs to a class of active galaxies known as blazars, which are highly variable in their light output. "OJ 287 shows a plethora of other brightness peaks not related to these 12-year cycles," says Miller. "Some of these peaks are higher than the ones from this recent cycle."

Miller also notes that as two supermassive black holes orbit each other in a binary, the orbit should slowly circularize itself. But the orbit in Valtonen's model is highly elongated. Only a third supermassive black hole, lurking somewhere nearby, could gravitationally perturb the system enough to explain the elongated orbit. Such a black hole cannot be ruled out, but at present there is no evidence for it.

If future observations confirm Valtonen's model, however, astronomers have struck gold. The two black holes will collide and merge within 10,000 years — a cosmic blink of an eye. The collision will release powerful gravitational waves that will convulse the fabric of space-time, releasing more total energy for several minutes than all the stars in the visible universe combined.

The binary black hole is already releasing gravitational waves, but not at a frequency that can be detected by current gravitational-wave observatories such as the Laser Interferometer Gravitational-Wave Observatory (LIGO) or future space missions such as the Laser Interferometer Space Antenna (LISA). But the existence of a relatively nearby supermassive black hole binary so close to coalescence would demonstrate unequivocally that such remarkable systems exist, bolstering the already impressive science case for developing LISA, which would catch their final inspiral, merger, and ringdown.



Fonte: Original desta notícia pode ser acessada através do site: http://www.gea.org.br/mss.html
Céu claro para todos!
José Geraldo Mattos - Moderador
"A desarmonia do universo é a mais perfeita criação; não foi e jamais será imitada pelo gênio humano" - (Prof. A. Seixas Neto)
Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com

Spinning-black-holes survey

New Chandra data reveal rapidy whirling black holes.

Provided by Chandra X-Ray Center

This illustration shows a close-up view of a supermassive black hole in a galaxy's center. NASA/CXC/M.Weiss [View Larger Image]
January 10, 2008
Results from NASA's Chandra X-ray Observatory, combined with new theoretical calculations, provide one of the best pieces of evidence yet that many supermassive black holes are spinning extremely rapidly.

The Chandra images show pairs of huge bubbles, or cavities, in the hot gaseous atmospheres of the galaxies, created in each case by jets produced by a central supermassive black hole. Studying these cavities allows the power output of the jets to be calculated.

The Chandra images were also used to estimate how much fuel is available for each supermassive black hole, using a simple model for the way matter falls towards such an object.

This artist's impression shows gas within a "sphere of influence" falling straight inwards towards a black hole before joining a rapidly spinning disk of matter near the center. NASA/CXC/M.Weiss [View Larger Image]
Previous work with these Chandra data showed that the higher the rate at which matter falls towards these supermassive black holes, the higher their power output is in jets. However, without detailed theory the implications of this result for black hole behavior were unclear. The new study uses these Chandra results combined with the leading theoretical models for the production of jets, plus general relativity, to show that the supermassive black holes in these galaxies must be spinning close to the maximum rate. If black holes are spinning at this limit, material can be dragged around them at close to the speed of light, the speed from Einstein's theory of relativity.


Fonte: Original desta notícia pode ser acessada através do site: http://www.gea.org.br/mss.html
Céu claro para todos!
José Geraldo Mattos - Moderador
"A desarmonia do universo é a mais perfeita criação; não foi e jamais será imitada pelo gênio humano" - (Prof. A. Seixas Neto)
Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com

Nuvens de gelo projetam sombras e neve de CO2 sobre superfície de Marte

Publicidade
da Efe, em Madri
A sonda européia Mars Express detectou nuvens de gelo tão densas que projetam sombras e produzem neves de CO2 (dióxido de carbono) sobre a superfície de Marte, afirma o cientista Agustín Chicarro.
O diretor-científico da missão, patrocinada pela ESA (Agência Espacial Européia), afirmou que os dados confirmam a presença de nuvens de dióxido de carbono que, junto com as mais conhecidas de vapor de água, formam o céu do planeta vermelho.
A descoberta é um passo importante no estudo do passado climático do quarto planeta do Sistema Solar, que sugere que este poderia ser muito mais quente há milhões de anos e fornece pistas para saber como aconteceu seu "resfriamento global".
O processo, inverso ao aquecimento da Terra, também permitirá comparar os dois fenômenos, mesmo sabendo que "as duas atmosferas são muito diferentes", ressaltou o cientista.
Os pesquisadores observaram pela primeira vez que as nuvens de CO2 --mais freqüentes no equador do planeta-- podem produzir "precipitações de neve". De acordo com os cientistas, trata-se de "um fenômeno muito curioso", que não havia sido observado antes em nenhum outro planeta do Sistema Solar.


Fonte:Original desta notícia pode ser acessada através do site: http://www.gea.org.br/mss.html

Céu claro pra todos!

José Geraldo Mattos
Moderador

"O que é inconcebível a respeito do universo é que ele é absolutamente concebível".(Albert Einstein)



Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com

verweight Neutron Stars?

Like many of us, neutron stars sometimes pack on more pounds than they should. We all know how humans get fat: by eating too much and exercising too little. But nobody knows how a handful of neutron stars end up heavier than the rest. So the apparent discovery of two new examples left astronomers scratching their heads at last week's meeting of the American Astronomical Society in Austin, Texas.

#checkImageURL M5
Globular cluster Messier 5 is about 25,000 light-years away in Serpens. Among its hundreds of thousands of stars is at least one millisecond pulsar — possibly one of the most massive neutron stars in our galaxy.
Sally & Curt King / Adam Block / NOAO / AURA / NSF
A neutron star is the remnant core of an intermediate-mass star, one that began its life with 8 to 20 or 30 times the mass of the Sun. As such a star evolves, it fuses light atomic nuclei into heavier and heavier ones. Eventually an iron core begins to build up at the star's center. Under the incredible pressure of the star's overlying layers, the core gets so highly compressed that the electrons in its constituent atoms pack down as tightly as the laws of quantum mechanics allow — a state termed electron degeneracy. If the core's mass grows to 1.44 Suns, the so-called Chandrasekhar limit, not even electron degeneracy can hold it up. The core suddenly collapses; its protons and electrons merge to form neutrons, and the sudden release of energy blows the rest of the star to smithereens in a supernova explosion. What's left is a 5- to 10-mile-wide neutron star — now held up by neutron degeneracy — surrounded by a glowing cloud of gas filaments.

That's the theory, anyway. It explains why nearly every neutron star discovered so far weighs less than 1.4 solar masses. It also explains why astronomers are puzzled by what Paulo Freire (Arecibo Observatory) and his colleagues think they've found in the globular clusters Messier 5 in Serpens and NGC 6440 in Sagittarius: neutron stars with masses of about 1.9 and 2.7 Suns, respectively.

The objects in question are millisecond pulsars: highly magnetic neutron stars spinning hundreds of times per second and spewing streams of particles and radiation that sweep past Earth with every turn. These objects are members of binary systems. Isolated neutron stars spin "only" a few times per second, but those in binaries can spin up to much higher rotation rates by accreting matter and angular momentum from their companions. Globular clusters are particularly rich hunting grounds for millisecond pulsars, because their high stellar density leads to an abundance of multiple-star systems.

M5 B is the more compelling of the two new discoveries. Using the giant radio telescope at Arecibo, Puerto Rico, Freire and his colleagues have monitored its pulses over a period of 18 years, leading to an extremely precise characterization of the binary. They derive masses of 1.94 ± 0.18 Suns for the pulsar and 0.16 ± 0.10 Sun for the companion. They can even detect the slow wander of the system's orbital axis predicted by Einstein's general theory of relativity. The millisecond pulsar in NGC 6440 was first detected only last year, so it'll be a while before Freire's team has enough timing measurements to confidently claim that it's even more massive than the one in M5 — though that's what they're guessing based on the observations they've made so far.

Our understanding of neutron-star interiors is still in its infancy. "Nobody really knows how matter behaves deep inside such an object," says Freire. To permit masses as high as that of M5 B, astronomers' models will have to be modified to treat neutron-star matter as more incompressible ("harder") than theorists expected.

The existence of such heavy neutron stars also argues that their inner material does not get squeezed into a sea of exotic "quark matter" rather than remaining as discrete neutrons (each of which consists of three quarks bound together in a package). An undifferentiated sea of free quarks should be (physicists think) more compressible than a sea of neutrons.

There's also the question of where the extra mass comes from. Perhaps a bit of stellar flotsam falls back onto the neutron star after its supernova blast. Or maybe there's a mechanism we haven't hit upon by which neutron stars form with masses above the Chandrasekhar limit. If that's the case, then neutron stars may be more prevalent than we thought — and, by extension, it may take more mass than we thought to overcome neutron degeneracy and produce a black hole.

You can learn more by reading these two technical papers by Freire and his colleagues: "A Massive Neutron Star in the Globular Cluster M5" and "Eight New Millisecond Pulsars in NGC 6440 and NGC 6441."

Fonte: Original desta notícia pode ser acessada através do site: http://www.gea.org.br/mss.html
Céu claro para todos!
José Geraldo Mattos - Moderador
"A desarmonia do universo é a mais perfeita criação; não foi e jamais será imitada pelo gênio humano" - (Prof. A. Seixas Neto)
Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com

Weird object may be result of colliding protoplanets

UNIVERSITY OF ARIZONA NEWS RELEASE
Posted: January 10, 2008


Something bizarre orbiting a young, failed star 170 light-years from Earth may be the progeny of two protoplanets that collided and merged, astronomers announced at the American Astronomical Society meeting in Austin, Texas.

Given its hotter-than-expected temperature, dim luminosity, young age and location, the orbiting object, known as 2M1207B, should be a physical impossibility, scientists say.

"This is a strange enough object that it needs a strange explanation," Eric Mamajek of the Harvard-Smithsonian Center for Astrophysics said.

Mamajek and Michael Meyer of The University of Arizona propose that the object orbiting brown dwarf 2M1207A is small, about the size of Saturn. The "brown dwarf," or failed star, in the system is believed to be 25 times as massive as Jupiter and only about eight million years old.

The brown dwarf might be the outcome of a collision between a Saturn-sized gas giant and a planet about three times the size of Earth, Mamajek and Meyer suggest. The two smacked into each other and fused, forming one larger world still boiling from the heat generated in the titanic collision.

"Most, if not all, planets in our solar system were hit early in their history," Mamajek said. "A collision created Earth's moon and knocked Uranus on its side. It's quite likely that major collisions happen in other young planetary systems, too."

"The Earth was hit by something one-tenth its mass, and it's likely that other planets in our solar system were, too, including Venus and Uranus," Meyer said. "If that one-tenth scale holds in other planetary systems, then we could be seeing the aftermath of a collision between a 72 Earth-mass gas giant and an eight Earth-mass planet."

The collision theory is reasonable from a timescale point of view, Mamajek said. A 2400-degree Fahrenheit, Saturn-sized object would radiate its heat away over about 100,000 years. If the system were billions of years old, it is unlikely that astronomers would be looking at the right time, but because the system is only eight million years old, chances are much better that they would catch it shortly after the collision, when they could still see the hot aftermath.

The collision hypothesis makes several predictions that astronomers can test. Chief among them is a low surface gravity, which depends on a planet's mass and radius. To check this prediction, astronomers will need to get a better spectrum of 2M1207B. That's challenging because the object is very faint and very close to the brown dwarf 2M1207A.

Mamajek emphasized that while a planet collision may not be the correct explanation for the weirdness of 2M1207B, examples of colliding planets are likely to be found by the next generation of ground-based telescopes.

"Hot, post-collision planets might be a whole new class of objects we will see with the Giant Magellan Telescope."

Harvard and UA are members of an international consortium building the Giant Magellan Telescope, which is slated for completion in 2016 at a site in northern Chile. It will be composed of seven 8.4-meter primary mirrors arranged in a hexagonal pattern, giving it 4.5 times the collecting area of any current optical telescope. The UA Steward Observatory Mirror Lab cast the first GMT mirror in 2005.

"Even if we're wrong, I wouldn't be surprised if someone finds a clear-cut case in the next 10 years," Mamajek added.


Fonte: Original desta notícia pode ser acessada através do site: http://www.gea.org.br/mss.html
Céu claro para todos!
José Geraldo Mattos - Moderador
"A desarmonia do universo é a mais perfeita criação; não foi e jamais será imitada pelo gênio humano" - (Prof. A. Seixas Neto)
Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com

Via Láctea abriga buracos negros solitários, afirmam pesquisadores

Publicidade
da France Presse, em Chicago
Centenas de buracos negros solitários perambulam pela Via Láctea à espera de estrelas e planetas que cruzem seu caminho e que possam ser envolvidos. A descoberta foi anunciada na quarta-feira (9) por astrônomos norte-americanos.
Os cientistas afirmam que estes buracos negros "de massa intermediária" são invisíveis --salvo em raras circunstâncias-- e foram produzidos por fusões de buracos negros de grupos globulares (enxames de estrelas que se mantiveram unidas por sua gravidade mútua).
Buracos negros são formações espaciais com enorme força gravitacional. Tanto que nada, nem mesmo a luz, pode escapar de sua ação. Por isso é que essas regiões ganharam tal nome.
Estes novos buracos negros dificilmente representariam uma ameaça à Terra, mas poderiam envolver nuvens, estrelas e planetas que atravessassem seu caminho, indicaram os pesquisadores.
"É extremamente improvável que estes buracos negros solitários causem algum dano na vida do universo", disse Holley-Bockelmann, professora assistente de física e astronomia da Universidade Vanderbilt em Nashville, no Tennessee.
"Sua zona de perigo, o Raio de Schwarzschild, (o raio gravitacional) é realmente minúsculo, com algumas poucas centenas de quilômetros. Há coisas muito mais perigosas na nossa vizinhança", explicou.
A evidência de buracos negros "de massa intermediária" e não buracos negros supermassivos é ainda teórica e, por isso, controversa. Só duas observações de corpos deste tipo foram realizadas até agora.


Fonte:Original desta notícia pode ser acessada através do site: http://www.gea.org.br/mss.html

Céu claro pra todos!

José Geraldo Mattos
Moderador

"O que é inconcebível a respeito do universo é que ele é absolutamente concebível".(Albert Einstein)


Posted by Lucimary Vargas

Para Guatemala.: El Asteroide cercano a la Tierra 2007 TU24 pasará cerca el 29 de enero


La fecha en la carta celeste debe decir 28 de enero de
2008. (se adjunta corregida)

Saludos,

La ubicación exacta de este asteroide, debido a que
pasará relativamente cerca de la tierra, depende de la
ubicación goegráfica desde donde se observe; Puede
variar más de un grado respecto de cualquier
información geocéntrica que pueda obtenerse en la
internet, sin embargo creo que sí es es posible
hallarlo con un telescopio de buena apertura y con un
aumento no mayor de 45x.

Para nuestra latitud en Guatemala la observación debe
hacerse esta noche del 28 de enero cuando el 2007TU24
cruce la constelación de Andrómeda, que es cuando su
movimiento aparente será de unos 2.9 grados por hora y
alcance su máximo brillo para nosotros (magnitud 10 o
ligeramente menor), de acuerdo a la trayectoria que se
muestra en la carta celeste adjunta. Más allá de
las 11 de la noche el asteroide estará muy bajo en el
horizonte oeste.

Para mañana martes 29 por la noche, el asteroide se
verá en la Osa Mayor, pero su movimiento aparente
habrá disminuido a menos de la mitad, aunque se espera
que su brillo sólo decaiga levemente.

Cielos despejados,

Jorge Solano
AGA

Earth Observatory

The latest from NASA's Earth Observatory
------------------------------------------------------------------------


In the News:
http://earthobservatory.nasa.gov/Newsroom/

* Latest Images:
La Nina Rainfall Patterns

http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17901

MESSENGER Views Mercury, Sends Earth a Postcard

http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17900

Great Sand Dunes National Park and Preserve, Colorado

http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17899

Kyushu, Japan

http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17898

Small Tropical Cyclones Contribute More to Annual Rainfall

http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17897

Ramsar Convention and Wetlands in Vietnam

http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17896

The Dawn of a New Solar Cycle

http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17895

La Nina Still Going in January 2008

http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17894

* NASA News

http://earthobservatory.nasa.gov/Newsroom/NasaNews/
- NASA Tsunami Research Makes Waves in Science Community
- 2007 Tied as Earth's Second Warmest Year

* Media Alerts

http://earthobservatory.nasa.gov/Newsroom/MediaAlerts/
- Record Warm Summers Cause Extreme Ice Melt in Greenland
- Alaska Glacier Speed-Up Tied to Internal 'Plumbing' Issues
- Evidence of Glaciation in 'Super Greenhouse' World
- A Warming Climate Can Support Glacial Ice
- Older Arctic Sea Ice Replaced by Young, Thin Ice
- Quakes Under Pacific Floor Reveal Unexpected Circulatory System
- Electric Sand Findings Could Lead to Better Climate Models

* Headlines from the press, radio, and television:

http://earthobservatory.nasa.gov/Newsroom/Headlines/
- Ancient Tsunami Behind Huge Yellowstone Explosion
- Northeast Winters Warming Fast
- Ice Sheets Existed During Global Heat Wave
- Desert Mystery Has Electrifying Answer
- Antarctic Trips to Boost Research
- As Arctic Ice Melts, South Pole Ice Grows
- 2007 was Another Warm Year for USA
- Deep Sea Vents: Hot, Wet, Weird
- Humans Blamed in Coral Reef Disappearance
- 'No Clear Trend' In Forest Loss
- Deep Sea Corals Under Scrutiny
- Placing Blame for Corals' Demise
- Climate researcher tackles New Guinea glaciers
- Reason for Earthquake Season Revealed
- Baby Mammoth Could Shed Light on Warming


---------------------------------------------------------------------
Earth Observatory weekly mailing -- http://earthobservatory.nasa.gov/

A Violent History of Time


NASA Science News for January 24, 2008

NASA is preparing to launch a new space telescope named GLAST to study the most violent explosions in the history of our Universe.

FULL STORY at

http://science.nasa.gov/headlines/y2008/24jan_glast.htm?list1073279

Check out our RSS feed at http://science.nasa.gov/rss.xml!

Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com

NOSSOS CÁLCULOS - LUA - FEVEREIRO DE 2008

NOSSOS CÁLCULOS – LUA

Fenômeno

Data

Hora (TU)

Nodo ascendente

07/2/2008

22h40

Nodo descendente

22/2/2008

12h13

Perigeu

14/02/2008

01h08

Apogeu

28/02/2008

01h27

Lua Nova

07/02/2008

03h45

Quarto Crescente

14/02/2008

03h34

Lua Cheia

21/02/2008

03h31

Quarto Minguante

29/02/2008

02h19

ECLIPSE DA LUA DE 20/21 DE FEVEREIRO (HORA DE BRASÍLIA)

Primeiro contato com a penumbra

9h38

Primeiro contato com a umbra

22h45

Início da fase total

0h02

Máximo do Eclipse

0h26

Final da fase total

0h51

Último contato com a umbra

2h08

Último contato com a penumbra

3h15

Atenciosamente

Marco Aurélio Álvares da Silva

Pirassununga - SP


.

__,_._,___

Asteroid Flyby

Space Weather News for Jan. 28, 2008
http://spaceweather.com

ASTEROID FLYBY: Asteroid 2007 TU24 is flying past Earth this wek at a
distance of only 334,000 miles (1.4 lunar distances). NASA radars tracking the asteroid confirm that there is no danger of a collision, but
it will be close enough for amateur astronomers to photograph through
mid-sized backyard telescopes. At closest approach on Jan. 29th, the
asteroid will glide through the constellations Andromeda and Cassiopeia
glowing like a 10th magnitude star. Visit http://spaceweather.com for
celestial coordinates and a low-resolution radar image of the approaching
rock.

HALO BONUS: A photographer in Finland has captured the long-sought "Kern
arc", a rare sun halo created by triangular ice crystals. Experts are
calling it the "halo photo of the decade" and it is featured on today's
edition of http://spaceweather.com.

Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com

.

MRO HiRISE Images - January 24, 2008

"Ron Baalke - Mars Exploration Program"


MARS RECONNAISSANCE ORBITER HIRISE IMAGES
January 24, 2008

o Southern Dunes and Spiders

http://hirise.lpl.arizona.edu/PSP_006538_1035

o Layered Sediments in Terby Crater

http://hirise.lpl.arizona.edu/PSP_006475_1525

o Splotches and Channels Near Sisyphi Montes

http://hirise.lpl.arizona.edu/PSP_005424_1075

o Polar Pit Gullies

http://hirise.lpl.arizona.edu/PSP_005410_1115


All of the HiRISE images are archived here:

http://hirise.lpl.arizona.edu/

Information about the Mars Reconnaissance Orbiter is online at
http://www.nasa.gov/mro. The mission is managed by NASA's Jet Propulsion
Laboratory, a division of the California Institute of Technology, for the
NASA
Science Mission Directorate, Washington, D.C. Lockheed Martin Space Systems,
of Denver, is the prime contractor and built the spacecraft. HiRISE is
operated by t
he University of Arizona. Ball Aerospace and Technologies Corp., of Boulder,
Colo.,
built the HiRISE instrument.


Visite nosso site: http://www.monoceros.xpg.com.br

Comunidade no Orkut: http://www.orkut.com/Community.aspx?cmm=11100690

Para visitar o site do seu grupo na web, acesse:
http://br.groups.yahoo.com/group/Observatorio_Monoceros/


Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com

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