terça-feira, 28 de outubro de 2008

Divulgados vencedores do Prêmio Nobel de Medicina e Fí­sica

 

 

Os destaques da medicina são para estudos sobre vírus da Aids e câncer de colo de útero. Contribuições ao Modelo Padrão da Física de Partículas e à previsão de novas famílias de quarks foram os temas premiados da física.
 
Nesta semana, os olhares do mundo convergem para os vencedores do Prêmio Nobel de 2008. Ontem foram anunciados os vencedores na área de medicina, hoje foram divulgados os ganhadores do prêmio de física. Amanhã, será a vez da química e na 5ª e 6ª feira serão divulgados os vencedores em literatura e paz. Na próxima 2ª feira será a vez do vencedor em economia.

A primeira cerimônia de premiação para as áreas de literatura, física, química e fisiologia ou medicina ocorreu no Conservatório Real de Estocolmo, em 1901. Desde 1902, os prêmios são formalmente entregues pelo Rei da Suécia. A entrega do Nobel da Paz no entanto foi sempre feita em Oslo, pelo Rei da Noruega.

Os prêmios são entregues anualmente, no dia 10 de dezembro, aniversário da morte de Alfred Nobel ─ seu criador. Os premiados recebem além de quantia em dinheiro ─ quase R$ 3 milhões ─ uma medalha de ouro cunhada com a imagem de Nobel (como a da ilustração) e um diploma, além de terem seus nomes lembrados para sempre por suas realizações extraordinárias que acabam mudando os destinos da humanidade.

Alfred Bernhard Nobel, que foi químico e inventor nasceu em Estocolmo, Suécia, em, 21 de outubro de 1833 e faleceu em San Remo, Itália, em 10 de dezembro de 1896.
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Lucimary Vargas
Presidente
Observatório Astronômico Monoceros
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com

Um visitante que não voltará ao espaço

 
2008-10-07

Uma das imagens da descoberta do asteróide 2008 TC3 (circulo violeta). Crédito: Richard Kowalski e Ed Beshore, Catalina Sky Survey.
Há poucos dias, no quadro de um projecto da NASA
National Aeronautics and Space Administration (NASA)
Entidade norte-americana, fundada em 1958, que gere e executa os programas espaciais dos Estados Unidos da América.
para a vigilância da vizinhança do nosso planeta
planeta
Um planeta é um objecto que se forma no disco que circunda uma estrela em formação e cuja massa é superior à de Plutão (1/500 da massa da Terra) e inferior a 10 vezes a massa de Júpiter. Ao contrário das estrelas, os planetas não produzem luz, apenas reflectem a luz da estrela que orbitam.
, foi descoberto no espaço, próximo da Terra, um pequeno asteróide
asteróide
Um asteróide é um pequeno corpo rochoso que orbita em torno do Sol, com uma dimensão que pode ir desde os 100 m até aos 1000 km. A maioria dos asteróides encontra-se entre as órbitas de Marte e de Júpiter. Também são designados por planetas menores.
(de poucos metros de diâmetro). Após várias observações, tornou-se claro que esta pedra do espaço se dirigia mesmo para nós. A notícia não provocou qualquer alarme, já que as dimensões deste objecto não permitiriam que atravessasse a atmosfera
atmosfera
1- Camada gasosa que envolva um planeta ou uma estrela. No caso das estrelas, entende-se por atmosfera as suas camadas mais exteriores. 2- A atmosfera (atm) é uma unidade de pressão equivalente a 101 325 Pa.
intacto. Refinados os cálculos, foi determinado que a entrada no invólucro gasoso que nos protege seria feita sobre a África, numa trajectória para leste, na madrugada passada, e que em poucos segundos o asteróide se transformaria numa bola de fogo (numa descrição simplista), oferecendo um magnífico espectáculo a quem estivesse na região. Dados os problemas existentes na área, e o nível de desenvolvimento tecnológico das populações locais, é pouco provável que nos cheguem relatos do solo. No entanto, à hora prevista, a tripulação de um avião da KLM avistou, a uma considerável distância, o fenómeno luminoso previsto. Foi a primeira vez que se previu o encontro entre o nosso planeta e um objecto menor do Sistema Solar
Sistema Solar
O Sistema Solar é constituído pelo Sol e por todos os objectos que lhe estão gravitacionalmente ligados: planetas e suas luas, asteróides, cometas, material interplanetário.
. É verdade que existem objectos de muito maiores dimensões a vogar pelo espaço e a cruzar a órbita
órbita
A órbita de um corpo em movimento é a trajectória que o corpo percorre no espaço.
que a Terra descreve em torno do Sol
Sol
O Sol é a estrela nossa vizinha, que se encontra no centro do Sistema Solar. Trata-se de uma estrela anã adulta (dita da sequência principal) de classe espectral G. A temperatura na sua superfície é aproximadamente 5800 graus centígrados e o seu raio atinge os 700 mil quilómetros.
, mas não vale a pena ficar assustado: as probabilidades de um encontro são infinitesimais, e este caso demonstra que já existe um esforço para localizar os objectos potencialmente perigosos – o primeiro passo para, em caso de necessidade, intervir e desviá-los do nosso planeta. Que, no passado, já sofreu impactos de vastas consequências, nomeadamente para a biosfera.

O que sucedeu a este pequeno asteróide – baptizado 2008 TC3 – pode ser resumido numa explosão com o poder equivalente a mil toneladas
tonelada (t)
A tonelada (t) é uma unidade de massa equivalente a 1000 kg.
de TNT, que iluminou o céu em redor como se fosse a Lua
Lua
A Lua é o único satélite natural da Terra.
cheia e produziu um magnífico espectáculo visual. Este destino ilustra bem o que se passa num planeta como o nosso, cuja superfície está protegida deste tipo de objectos por uma atmosfera relativamente densa. Apesar de existirem diversos factores a ditarem o destino de um objecto que a penetra – as dimensões, claro, mas também a velocidade relativa, o ângulo de entrada e as propriedades físicas do objecto – a atmosfera cobra um elevado preço pela passagem. Todos já observaram uma "estrela
estrela
Uma estrela é um objecto celeste gasoso que gera energia no seu núcleo através de reacções de fusão nuclear. Para que tal possa suceder, é necessário que o objecto possua uma massa superior a 8% da massa do Sol. Existem vários tipos de estrelas, de acordo com as suas temperaturas efectivas, cores, idades e composição química.
cadente": não passa geralmente de uma partícula de muito pequenas dimensões que depressa é consumida pelo atrito na descida pela atmosfera. Quando se trata de objectos de maiores dimensões, uma analogia simples pode ajudar a perceber os acontecimentos: numa série televisiva que passa num canal de cabo, os "Caçadores de Mitos" experimentaram disparar armas de fogo contra a água, numa piscina. Quando utilizaram uma arma que imprimia grande velocidade ao projéctil, não o encontraram no fundo da piscina: ao penetrar na água, um meio muito mais resistente do que o ar, o projéctil tinha sido despedaçado. Imaginemos agora o que acontece a um asteróide que viaja pelo espaço, sem resistência, e entra numa atmosfera… A pressão, para lá de aquecer a frente do objecto, leva facilmente à sua destruição completa. Muitas vezes tudo o que chega ao solo são pequenos meteoritos
meteorito
Um meteorito é um corpo sólido que entra na atmosfera da Terra (ou de outro planeta), sendo suficientemente grande para não ser totalmente destruído pela fricção com as partículas da atmosfera, e assim atingir o solo. Os meteoritos dividem-se em três categorias, segundo a sua composição: aerolitos (rochosos), sideritos (ferro) e siderolitos (ferro e rochas).
, já sem a velocidade que traziam do espaço, o que explica que nem sequer cheguem a produzir crateras. Outras vezes, todo o objecto explode em altitude, embora possam sobreviver fragmentos importantes (como se pensa agora que sucedeu em Tunguska, em 1908). Claro que nem sempre isto se passa assim (veja-se o caso do Peru, no ano passado). E depois, há que contar com aqueles objectos de maiores dimensões, que fazem da atmosfera pouco mais do que uma película facilmente ultrapassável… como os dinossauros e muitos outros tipos de animais descobriram, há 65 milhões de anos atrás. Para isso, existem projectos, não apenas de vigilância sideral, mas mesmo de visita a asteróides por missões automáticas, de forma a compreender melhor a sua estrutura e as possibilidades de agir (destruir ou desviar) sobre objectos de dimensões e massas importantes.
 
 

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Lucimary Vargas
Presidente
Observatório Astronômico Monoceros
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com

Stars stop forming when big galaxies collide

YALE UNIVERSITY NEWS RELEASE
Posted: October 7, 2008


NEW HAVEN, Conn. - Astronomers studying new images of a nearby galaxy cluster have found evidence that high-speed collisions between large elliptical galaxies may prevent new stars from forming, according to a paper to be published in a November 2008 issue of The Astrophysical Journal Letters.


A deep image of part of the Virgo cluster revealing tendrils of ionized hydrogen gas 400,000 light-years long that connect the elliptical galaxy M86 (right) and the disturbed spiral galaxy NGC 4438 (left). Credit: Tomer Tal and Jeffrey Kenney/Yale University and NOAO/AURA/NSF
 
Led by Jeffrey Kenney, professor and chair of astronomy at Yale, the team saw a spectacular complex of warm gas filaments 400,000 light-years-long connecting the elliptical galaxy M86 and the spiral galaxy NGC 4438 in the Virgo galaxy cluster, providing striking evidence for a previously unsuspected high-speed collision between the galaxies. The view was constructed using the wide-field Mosaic imager on the National Science Foundation telescope at Kitt Peak National Observatory near Tucson, Arizona.

"Our data show that this system represents the nearest recent collision between a large elliptical galaxy and a large spiral galaxy," said Kenney, who is lead author of the paper. "This discovery provides some of the clearest evidence yet for high-speed collisions between large galaxies, and it suggests a plausible alternative to black holes as an explanation of what turns off star formation in the biggest galaxies."

Previously, scientists had seen the filaments of gas around both galaxies, but had not seen or inferred any connection between the two galaxies located approximately 50 million light-years from Earth. The new image shows extended and faint emissions that directly connect the two galaxies - and there are no obvious stars in the filaments.

As in most elliptical galaxies, gas within M86 is extremely hot, and radiates X-rays in a long plume, which had previously been interpreted as a tail of gas being stripped as M86 falls into the Virgo cluster. The new image suggests that most of the disturbances in M86 are instead due to the collision with NGC 4438.

"Like with a panoramic camera, the view from the telescope using the wide-field imager at Kitt Peak let us see the bigger picture," said Kenney. "We needed to look deep and wide to see the M86 complex."

A current mystery in astronomy is what causes the biggest galaxies in the universe -primarily elliptical galaxies like M86 - to stop forming stars. "Something needs to heat up the gas so it doesn't cool and form stars," Kenney says. "Our new study shows that gravitational interactions may do the trick."

According to the authors, low-velocity collisions between small- or medium-sized galaxies often produce an increase in the local star formation rate, but in high-velocity collisions that happen naturally between large galaxies, the energy of the collision can cause the gas to heat up so much that it cannot easily cool and form stars.

"The same physical processes occur in both strong and weak encounters, and by studying the observable effects in extreme cases like M86 we can learn about the role of gravity in the heating of galaxy gas, which appears to be quite significant," Kenney adds.

Co-authors of the study include Yale graduate student Tomer Tal, former Yale student Hugh Crowl, now at the University of Massachusetts, WIYN Observatory Director George Jacoby, and John Feldmeier of Youngstown State University.

Kitt Peak National Observatory is part of the National Optical Astronomy Observatory (NOAO), which is operated by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. The founding members of the WIYN Observatory partnership are the University of Wisconsin, Indiana University, Yale University, and NOAO.
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Lucimary Vargas
Presidente
Observatório Astronômico Monoceros
Além Paraíba-MG-Brasil

Arizona State University research team selected to guide search for life

New approach goes from "follow the water" to "follow the elements".
Provided by Arizona State University
eukaryote cell with a supernova exploding
This conceptual image of a eukaryote cell with a supernova exploding in its nucleus symbolizes the idea that the chemical elements that make up living things are produced in stars and stellar explosions, encapsulating the range of research in the project. Nahks Tr'Ehnl [View Larger Image]
October 6, 2008
The quest for habitable worlds has focused on searching for water, but following the water turns out to be too general a criterion. The list of planets and satellites that possess liquid water is growing faster than can be explored. As one of the new NASA Astrobiology Institute teams, Arizona State University (ASU) researchers intend to boost extraterrestrial exploration by refining the criteria that guide the search for life.

The multidisciplinary field of astrobiology explores the origin, evolution, distribution, and future of life on Earth and in the universe. The need for experts in areas as diverse as Earth and planetary science, astrophysics, microbiology, cosmochemistry, and evolutionary biology, gave rise to the NASA Astrobiology Institute (NAI). Established as part of NASA's Astrobiology Program, the NAI developed as a partnership between NASA and teams located at academic institutions, research laboratories, and NASA centers across the United States. More than 700 scientists and educators are associated with the NAI.

NASA announced October 2, that ASU's School of Earth and Space Exploration is one of 10 research teams from across the country to be awarded 5-year grants, averaging $7 million each. ASU previously operated as an NAI team and was a charter member of the NAI when the program was founded in 1998. The team is centered in the School of Earth and Space Exploration but also involves several faculty members from the School of Life Sciences, the Department of Chemistry and Biochemistry and the Beyond Center.

"Few scientific questions capture the imagination like studies of the origin of life. Such research is central to the mission of the School of Earth and Space Exploration," says Kip Hodges, director of the school.
Jupiter's moon Europa
This false-color image of the surface of Jupiter's moon Europa taken from the Galileo mission shows evidence of elements that could have come from a subsurface water ocean. NASA/JPL/University of Arizona [View Larger Image]
The ASU team is joined by researchers from partner institutions and centers including University of California at Riverside, University of California at Merced, Rice University, and University of Illinois at Chicago, as well as NASA Goddard Space Flight Center, the Australian Centre for Astrobiology at the University of New South Wales and the National Autonomous University of Mexico. Under the direction of Anbar, the team plans to refine the criteria to guide the search for life by characterizing life's elemental requirements.

Astrobiologists assume that life may develop and survive on any planet that has water and energy. But in the search for extraterrestrial life, these criteria are too vague. Within the solar system there is abundant evidence of water-rich environments. Focused exploration on Mars has identified many ancient aqueous environments, Galileo spacecraft data indicate that Europa's icy crust conceals a salty ocean, and the Cassini mission discovered water jets on Enceladus. Beyond the solar system, there are probably many Earth-like planets. Theories suggest that many of these planets are waterworlds, with oceans so deep that they have no exposed continents. All of these environments have sufficient energy to support microbial life.

"Water and energy are necessary but not sufficient," says Anbar. "Look at Earth. Nearly half the planet's surface is covered by ocean regions in which life is scarce. The reason is that these regions don't have high enough concentrations of the chemical elements necessary for life. So the next step in the search for life is to follow the elements."

The team will pursue a three-pronged research initiative to explore the relationship between the elemental composition of organisms and their environments, the impact of planetary processes on the abundance of bioessential elements, and the effects of astrophysical processes on the abundance of life-supporting elements.

Planetary missions within the solar system are expensive and rare and investigations outside the solar system are not feasible for all of the hundreds of anticipated Earth-like planets with liquid water. The resources available for astrobiology exploration are limited, so narrowing down the search criteria will be beneficial.

Yet impacts of this research extend beyond aiding in the targeting and interpretation of data from space missions. In line with the School of Earth and Space Exploration's mission of improving science literacy both on and off campus, the ASU team has plans to engage students and teachers in the discovery process through virtual field trips and educator workshops, and an innovative approach to training secondary school science teachers.

"The opportunities this provides for us to raise the profile of astrobiology in our graduate and undergraduate educational programs is especially exciting," says Hodges.
 
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Lucimary Vargas
Presidente
Observatório Astronômico Monoceros
Além Paraíba-MG-Brasil

Major Bolide Forecast Last Night

Update 9:30 a.m. EDT, Oct 7

So far, there has been one likely confirmation of the fireball by a KLM flight 750 nautical miles from the impact site, as reported on spaceweather.com. But there have been no reports from the ground, though thousands or even millions of people must have witnessed it. Stay tuned for further developments.

The original story continues below

Many telescopes around the world are dedicated to scanning the sky, looking for asteroids that might potentially hit Earth. Many candidates have been found, and some have received widespread coverage in the mainstream press. But when the trajectories have been computed, all of them have turned out to be false alarms — until now!

Last night (Sunday, October 5th), a telescope on Mount Lemmon, Arizona, detected a tiny moving blip, the signature of a small chunk of rock moving rapidly through space. Twenty-five observations have been done since then by professional and amateur astronomers around the world, and the object's orbit has been pinned down with fairly high precision. It is almost certain to hit Earth's atmosphere around 10:46 p.m. EDT tonight, October 6th. (That's 2:46 a.m. October 7th, Greenwich Mean Time.)

The rock is roughly 10 feet (3 meters) across, and it's expected to enter the atmosphere above northern Sudan at about 8 miles (12 km) per second. The energy released should be approximately equal to one kiloton of conventional explosives. Fortunately, no damage is expected, since the blast will take place in the upper atmosphere. Some fragments may fall to the ground, but the area is sparsely inhabited and they're unlikely to hit anyone.

The sight and sound, however, should be amazing — especially since the sky will still be dark when this meteor hits. The fireball may be visible over much of northern Africa, the Middle East, and possibly even southern Europe.
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Lucimary Vargas
Presidente
Observatório Astronômico Monoceros
Além Paraíba-MG-Brasil

Cassini flyby of Saturn moon to offer insight into solar system history

Scientists are preparing for spacecraft to venture deeper than ever before to sample atoms in Enceladus' atmosphere.
Provided by University of Michigan at Ann Arbor
Enceladus
This sweeping mosaic of Saturn's moon Enceladus provides broad regional context for the ultra-sharp, close-up views NASA's Cassini spacecraft acquired minutes earlier, during its flyby on Augugst 11, 2008. NASA/JPL/Space Science Institute [View Larger Image]
October 7, 2008
NASA's Cassini spacecraft is scheduled to fly within 16 miles (26 km) of Saturn's moon Enceladus October 9. During the flyby, the spacecraft will measure molecules in its space environment that could give insight into the history of the solar system.

"This encounter will potentially have far-reaching implications for understanding how the solar system was formed and how it evolved," said professor Tamas Gombosi, chair of the University of Michigan Department of Atmospheric, Oceanic and Space Sciences. Gombosi is the interdisciplinary scientist for magnetosphere and plasma science on the Cassini mission. He coordinates studies that involve multiple plasma instruments on the spacecraft.


Enceladus is Saturn's sixth largest moon, orbiting within the planet's outermost ring. It is approximately 313 miles (504 km) in diameter.

In this flyby, Cassini will be close enough to Enceladus to identify individual molecules in the moon's space environment, including ions and isotopes. An ion is a charged particle, or a version of an element that has lost or gained negatively charged electrons. An isotope is a version of an element that has in its nucleus the typical protons for that element, but a different number of neutrons, thus exhibiting a different atomic weight.

The atoms around Enceladus are expected to hold clues to the past because they come from interior regions that have changed little since the moon was formed. Geysers near the moon's south pole spew water and other molecules from the satellite's interior. Because of Enceladus' weak gravity and low atmospheric pressure, the water and gas molecules waft off to space.

The encounter will contribute to scientists' understanding of how particles become charged and energized in Saturn's magnetosphere. Also, when Cassini identifies the different isotopes in the space around the moon, it will help scientists discern the temperatures at various stages in Enceladus' formation eons ago.

Cassini discovered the geysers on Enceladus in 2005. Scientists believe that there could be a liquid ocean beneath the moon's surface. They also detected organic molecules at the moon in March. Organic molecules have carbon-hydrogen bonds, and are found in living organisms, and in comets.

"The mission as a whole is expected to bring central pieces of the solar system evolution puzzle into place," Gombosi said. "This encounter is expected to provide some of those puzzle pieces."

This will be Cassini's fifth encounter with Enceladus. A sixth encounter, during which it will approach within 122 miles (196 km) of the moon, is scheduled for October 31. Four more flybys are planned in the next 2 years of Cassini's extended mission, the Cassini Equinox Mission.
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Lucimary Vargas
Presidente
Observatório Astronômico Monoceros
Além Paraíba-MG-Brasil

Prêmio Nobel de Física de 2008, pelo trabalho co


física
Em Estocolmo
Dois cientistas japoneses e um norte-americano nascido em Tóquio dividiram o prêmio Nobel de Física de 2008, pelo trabalho com física subatômica, informou o comitê do prêmio na terça-feira.

  • Itsuo Inouye/AP O cientista japonês Makoto Kobayashi concede entrevista após saber que venceu o Nobel
    O comitê premiou Yoichiro Nambu, cidadão norte-americano nascido em Tóquio, pela descoberta do mecanismo de "quebra espontânea de simetria em física subatômica".
    Ele divide metade do prêmio de 10 milhões de coroas suecas (1,4 milhão de dólares) com Makoto Kobayashi e Toshihide Maskawa, laureados pelo trabalho que previu a existência de pelo menos três famílias de quarks (uma das três partículas hipotéticas que constituiriam a base de todas as partículas atômicas conhecidas) na natureza.
    O prêmio, concedido pelo Comitê Nobel de Física da Academia Real Sueca de Ciências, foi o segundo entregue este ano. Na segunda-feira, foram conhecidos os vencedores do prêmio Nobel de medicina.
    Os prêmios são entregues anualmente para pessoas que se destacam nas áreas de ciências, literatura, paz e economia. Os prêmios levam o nome de Alfred Nobel, milionário sueco que inventou a dinamite, e começaram no ano de 1901, como estabeleceu o testamento deixado por Nobel em 1895.
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    Lucimary Vargas
    Presidente
    Observatório Astronômico Monoceros
    Além Paraíba-MG-Brasil

    Swift catches farthest-ever gamma-ray burst

    NASA NEWS RELEASE
    Posted: September 19, 2008


    WASHINGTON -- NASA's Swift satellite has found the most distant gamma-ray burst ever detected. The blast, designated GRB 080913, arose from an exploding star 12.8 billion light-years away.


    This image merges the view through Swift's UltraViolet and Optical Telescope, which shows bright stars, and its X-ray Telescope, which captures the burst (orange and yellow). Credit: NASA/Swift/Stefan Immler
     
    "This is the most amazing burst Swift has seen," said the mission's lead scientist Neil Gehrels at NASA's Goddard Space Flight Center in Greenbelt, Md. "It's coming to us from near the edge of the visible universe."

    Because light moves at finite speed, looking farther into the universe means looking back in time. GRB 080913's "lookback time" reveals that the burst occurred less than 825 million years after the universe began.

    The star that caused this "shot seen across the cosmos" died when the universe was less than one-seventh its present age. "This burst accompanies the death of a star from one of the universe's early generations," says Patricia Schady of the Mullard Space Science Laboratory at University College London, who is organizing Swift observations of the event.

    Gamma rays from the far-off explosion triggered Swift's Burst Alert Telescope at 1:47 a.m. EDT on Sept. 13. The spacecraft established the event's location in the constellation Eridanus and quickly turned to examine the spot. Less than two minutes after the alert, Swift's X-Ray Telescope began observing the position. There, it found a fading, previously unknown X-ray source.

    Astronomers on the ground followed up as well. Using a 2.2-meter telescope at the European Southern Observatory in La Silla, Chile, a group led by Jochen Greiner at the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, captured the bursts fading afterglow.

    The telescope's software listens for alerts from Swift and automatically slewed to the burst position. Then, the team's Gamma-Ray Burst Optical/Near-Infrared Detector, or GROND, simultaneously captured the waning light in seven wavelengths. "Our first exposure began just one minute after the X-Ray Telescope started observing," Greiner says.

    In certain colors, the brightness of a distant object shows a characteristic drop caused by intervening gas clouds. The farther away the object is, the longer the wavelength where this fade-out begins. GROND exploits this effect and gives astronomers a quick estimate of an explosion's shift toward the less energetic red end of the electromagnetic spectrum, or "redshift," which suggests its record-setting distance.

    An hour and a half later, as part of Greiner's research, the Very Large Telescope at Paranal, Chile, targeted the afterglow. Analysis of the spectrum with Johan Fynbo of the University of Copenhagen established the blasts redshift at 6.7 -- among the most distant objects known.

    Gamma-ray bursts are the universe's most luminous explosions. Most occur when massive stars run out of nuclear fuel. As their cores collapse into a black hole or neutron star, gas jets -- driven by processes not fully understood -- punch through the star and blast into space. There, they strike gas previously shed by the star and heat it, which generates bright afterglows.

    The previous record holder was a burst with a redshift of 6.29, which placed it 70 million light-years closer than GRB 080913.

    Swift, launched in November 2004, has had a banner year. In March, the satellite detected the brightest gamma-ray burst, which was visible to the human eye despite occurring billions of light-years away. And in January, the spacecraft's instruments caught the first X-rays from a new supernova days before optical astronomers saw the exploding star.

    Swift is managed by Goddard. It was built and is being operated in collaboration with Penn State University, University Park, Pa., the Los Alamos National Laboratory in New Mexico, and General Dynamics of Gilbert, Ariz., in the U.S. International collaborators include the University of Leicester and Mullard Space Sciences Laboratory in the United Kingdom, Brera Observatory and the Italian Space Agency
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    Lucimary Vargas
    Presidente
    Observatório Astronômico Monoceros
    Além Paraíba-MG-Brasil

    Is This an Alien Planet?

    Discovering a planet around another star is no big deal these days — dozens of them have been reported in 2008 alone, and the total count now stands at more than 300.

    Of course, the burgeoning exoplanet population hasn't stopped astronomers from looking for more of them. Big gaps remain in the sampling statistics, because the most successful techniques (radial-velocity monitoring, microlensing events, and periodic transits) favor finding large bodies close to their parent stars. Far-out planets are rarely discovered this way because they have long orbital periods and even longer odds of crossing directly in front of their stars.

    But it should be possible to spot alien worlds directly by imaging very young nearby stars. This game plan assumes that any outlying gas-giant planets are still glowing warmly from having formed so recently, making them relatively easy pickings at infrared wavelengths. One of these came to light in 2004, though it orbits a feebly glowing brown dwarf rather than a proper star.

    Image of an alien planet?
    The young star 1RXS J160929.1-210524 and, at upper left, its putative planet. The separation is 2.2 arcseconds — about 330 astronomical units at the star's distance of about 500 light-years. This false-color composite utilizes images taken at three infrared wavelengths; north is up.
    Gemini Observatory
    Now a trio of astronomers from the University of Toronto has found a "planetary-mass candidate" next to a young star that has roughly the Sun's mass. To see it, last April they utilized an adaptive-optics-aided infrared imager attached to the Gemini North telescope atop Mauna Kea in Hawaii.

    The press release announcing the discovery touts the "First Picture of Likely Planet," but astronomers David Lafrenière, Ray Jayawardhana, and Marten van Kerkwijk are stopping short of calling it that.

    For one thing, there's no information yet on the characteristics of its orbit — or, indeed, whether it's even bound to the star at all. They do know that it's not a star, because it's not very hot (about 1,800 kelvins, or 2,700°F) and its infrared spectrum reveals the presence of water and carbon monoxide. Most likely it's about 8 times the mass of Jupiter.

    The parent star, which has the snappy designation 1RXS J160929.1-210524, lies about 500 light-years from Earth. So the putative planet's apparent separation of 2.2 arcseconds corresponds to about 330 astronomical units. That's already raised eyebrows among solar-system modelers, because it's highly unlikely that so massive a planet could have formed so far from its star.

    The observing team has looked at more than 80 other stars in a 5-million-year-old grouping called the Upper Scorpius Association, and this is the only candidate planet they've turned up to date.

    Jayawardhana admits that calling it a "planet" is a stretch; more likely, it's a "failed" binary star with a seriously stunted secondary. However, he notes that a massive planet might conceivably have formed closer in and then been tossed outward by a chance encounter with another large planet soon after the young star formed.

    The true nature of 1RXS J160929.1-210524's companion probably won't become clear anytime soon. Its orbital period is likely thousands of years. At best, the team hopes to confirm that the star and its companion are moving together in space. "If we confirm that this object is indeed gravitationally tied to the star, it will be a major step forward," says Lafrenière. Those observations will have to wait until next spring, when the pair emerges from behind the Sun.

    The observers have submitted their findings to Astrophysical Journal Letters for publication, but you can get a sneak peak in this online posting.
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    Lucimary Vargas
    Presidente
    Observatório Astronômico Monoceros
    Além Paraíba-MG-Brasil

     _,_._,___

    Europe's station resupply ship concludes mission

    BY STEPHEN CLARK
    SPACEFLIGHT NOW

    Posted: September 29, 2008


    An historic chapter in Europe's space program came to a close Monday when Jules Verne, a human-rated supply ship for the international space station, completed its mission with a fiery suicidal plunge into Earth's atmosphere.


    Credit: ESA
     
    Two engine firings Monday morning slowed the spacecraft's velocity by about 224 mph and lowered its orbit into the upper atmosphere. The 30,000-pound ship first encountered the outer fringes of the atmosphere at 1331 GMT (9:31 a.m. EDT) over an uninhabited part of the South Pacific.

    "The trajectory was pin-point and this, together with a break-up behavior close to our models, means that the re-entry posed no safety hazard," said Bob Chesson, head of the European Space Agency's human spaceflight and exploration operations.

    Chesson said telemetry from the doomed spacecraft showed the ship's four X-shaped solar arrays shearing away at an altitude of about 100 kilometers, or 62 miles.

    Engineers at the ATV control center in Toulouse, France, continued to receive data from the craft's transmitters at an altitude of 80 kilometers, or about 50 miles, Chesson said.

    Telemetry indicated the vehicle begin breaking apart a few moments later at an altitude of 75 kilometers, or 47 miles, according to Chesson.

    Burning up along with Jules Verne Monday was more than 1,800 pounds of discarded dry cargo and 582 pounds of liquid waste from the station. The crew filled the ship's pressurized cargo carrier and water tanks with garbage during its five-month stay at the outpost.

    Jules Verne delivered more than 10,000 pounds of supplies to the complex in early April. The Automated Transfer Vehicle employed a futuristic rendezvous and docking system using lasers to automatically approach the station.

    "Credit has to go to everyone involved in such a flawless mission," said John Ellwood, ATV project manager.

    The spacecraft, the first of its kind developed by Europe, launched March 9 aboard an Ariane 5 rocket from the Guiana Space Center in South America.

    The first ATV was named Jules Verne after the visionary 19th science fiction writer.

    Four more ATV missions are on the books through 2015 for more cargo delivery missions to the station. The next ATV launch is scheduled for the middle of 2010, according to ESA.

    "This is truly a wonderful spacecraft, and vital to the continued service of the ISS following shuttle retirement in 2010," Ellwood said.

    Since undocking from the space station Sept. 5, the first Automated Transfer Vehicle spent more than three weeks undergoing further tests and moving its orbit below the complex.

    The orbit maneuvers set up nighttime re-entry opportunities over the South Pacific and allowed the station's three-man crew to observe the demise of Jules Verne.

    Two NASA airplanes, a Gulfstream V research jet and a DC-8 airborne laboratory, flew from California to Tahiti Friday night with a group of more than 30 scientists and instruments to view the ATV's re-entry.

    The planes included optical, infrared and ultraviolent imagers and spectrometers, according to ESA officials.

    The scientists returned images and video to NASA and ESA when they returned to their staging base in Tahiti a few hours after Jules Verne's re-entry.

    The observation campaign was headed by NASA's Ames Research Center, ESA and the SETI Institute. It was similar to research missions that studied the re-entry of NASA's Stardust and Genesis probes.

    Officials hoped to gain insight into how spacecraft break apart during the heating of re-entry. Scientists were also interested in comparing data from the ATV entry to information about the fragmentation of meteorites burning up in Earth's atmosphere. 

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    Lucimary Vargas
    Presidente
    Observatório Astronômico Monoceros
    Além Paraíba-MG-Brasil


     


    __,_._,___

    Three-dimensional look at Venus' raging winds

    BY DR EMILY BALDWIN
    ASTRONOMY NOW

    Posted: September 22, 2008
    ESA's Venus Express spacecraft, the most powerful atmospheric investigator ever sent to Venus, has put together the first 3D picture of the fierce winds that roar across the planet's southern hemisphere.

    Click for animation of Venus' wind circulation, the first 3D picture of the venusian winds for an entire planetary hemisphere. Image: ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA/ Universidad del País Vasco (R.Hueso).

    Since 2006, the Venus Express Visual and Infrared Thermal Imaging Spectrometer (VIRTIS) has been studying the thick blanket of clouds that shroud Venus above the southern hemisphere, spanning altitudes of 45 to 70 kilometres (km) above the surface. It is above the southern hemisphere that Venus Express reaches its highest point in orbit (about 66,000 km), providing a global view of the planet's atmospheric phenomena. The study focused on the clouds and their movement, tracking them for long periods of time to determine the variation in the speeds of the winds.
    "We have determined simultaneously for the first time the vertical structure of the zonal winds of Venus within their main cloud decks," lead researcher Agustin Sanchez-Lavega from the Universidad del Pais Vasco in Bilbao, Spain, tells Astronomy Now. "This has been done for the whole southern hemisphere, from equator to pole. These and the other measurements (meridional wind, wind variability) will help to constraint existing models of Venus' general circulation."
    Because VIRTIS operates at different wavelengths, clouds at different altitudes can easily be tracked. The team studied three atmospheric layers and followed the movement of hundreds of clouds in each: 625 clouds at 66 km altitude, 662 at 61 km altitude, and 932 at 45-47 km altitude, on the day and night sides of the planet. The individual cloud layers were imaged over several months for about 1-2 hours each time, a first for atmospheric study of Venus, which has never been done before at such large temporal and spatial scales and with multi-wavelength coverage.

    VIRTIS measured wind speeds and cloud movements at three different altitudes using different infrared wavelengths to penetrate each layer. Image: R.Hueso, Universidad del Pais Vasco.

    "We have learnt that between the equator and 50-55? latitude south, the speed of the winds varies a lot, from about 370 km/hour at a height of 66 km down to about 210 km/hour at 45-47 km," says Sanchez-Lavega. "At latitudes higher than 65?, the situation changes dramatically - the huge hurricane-like vortex structure present over the poles takes over. All cloud levels are pushed on average by winds of the same speed, independently of the height, and their speed drops to almost zero at the centre of the vortex."
    Sanchez-Lavega and colleagues observed that the speed of the zonal winds (which blow parallel to the lines of latitude) strongly depend on local time, which could be related to differences in heat reaching Venus in the mornings and in the evenings. This effect, called the solar tide effect, influences the atmospheric dynamics greatly, making winds blow more strongly in the evenings.
    "Solar radiation is the only driver of Venus atmospheric motions," explains Sanchez-Lavega. "Most radiation is deposited at cloud level, although the high temperatures at the surface are due to the runaway greenhouse effect. The problem is that we do not know how this heating translates into the strong observed motions. This is an open problem in Venus."

    The study shows that on average, the winds regain their original speeds every five days, but the mechanism that produces this periodicity is unclear. VIRTIS is expected to provide the missing answers during its next few years of operation.

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    Lucimary Vargas
    Presidente
    Observatório Astronômico Monoceros
    Além Paraíba-MG-Brasil
    observatorio.monoceros@gmail.com

    Orbiter reveals rock fracture plumbing on Mars

    NASA/JPL NEWS RELEASE
    Posted: September 30, 2008


    PASADENA, Calif. -- NASA's Mars Reconnaissance Orbiter has revealed hundreds of small fractures exposed on the Martian surface that billions of years ago directed flows of water through underground Martian sandstone.


    Dense clusters of crack-like structures called deformation bands form the linear ridges prominent in this image from the HiRISE camera on Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/Univ. of Arizona
     
    Researchers used images from the spacecraft's High Resolution Imaging Science Experiment, or HiRISE, camera. Images of layered rock deposits at equatorial Martian sites show the clusters of fractures to be a type called deformation bands, caused by stresses below the surface in granular or porous bedrock.

    "Groundwater often flows along fractures such as these, and knowing that these are deformation bands helps us understand how the underground plumbing may have worked within these layered deposits," said Chris Okubo of the U.S. Geological Survey in Flagstaff, Ariz.

    Visible effects of water on the color and texture of rock along the fractures provide evidence that groundwater flowed extensively along the fractures.

    "These structures are important sites for future exploration and investigations into the geological history of water and water-related processes on Mars," Okubo and co-authors state in a report published online this month in the Geological Society of America Bulletin.

    Deformation band clusters in Utah sandstones, as on Mars, are a few yards wide and up to a few miles long. They form from either compression or stretching of underground layers, and can be precursors to faults. The ones visible at the surface have become exposed as overlying layers erode away. Deformation bands and faults can strongly influence the movement of groundwater on Earth and appear to have been similarly important on Mars, according to this study.

    "This study provides a picture of not just surface water erosion but true groundwater effects widely distributed over the planet," said Suzanne Smrekar, deputy project scientist for the Mars Reconnaissance Orbiter at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Ground water movement has important implications for how the temperature and chemistry of the crust have changed over time, which in turn affects the potential for habitats for past life."

    The recent study focuses on layered deposits in Mars' Capen crater, approximately 43 miles in diameter and 7 degrees north of the equator. This formerly unnamed crater became notable due to this discovery of deformation bands within it and was recently assigned a formal name. The crater was named for the late Charles Capen, who studied Mars and other objects as an astronomer at JPL's Table Mountain Observatory in southern California and at Lowell Observatory, Flagstaff, Ariz.

    The HiRISE camera is one of six science instruments on the orbiter. It can reveal smaller details on the surface than any previous camera to orbit Mars. The orbiter reached Mars in March 2006 and has returned more data than all other current and past missions to Mars combined.

    The mission is managed by JPL for NASA's Science Mission Directorate. Lockheed Martin Space Systems of Denver built the spacecraft. The University of Arizona operates the HiRISE camera, built by Ball Aerospace and Technology Corp. of Boulder, Colo.

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    Lucimary Vargas
    Observatório Astronômico Monoceros
    Além Paraíba-MG-Brasil

     

    Infrared echoes give Spitzer a supernova flashback

    NASA NEWS RELEASE
    Posted: October 1, 2008

    GREENBELT, Md. -- Hot spots near the shattered remains of an exploded star are echoing the blast's first moments, say scientists using data from NASA's Spitzer Space Telescope.

    Eli Dwek of NASA's Goddard Space Flight Center in Greenbelt, Md. and Richard Arendt of the University of Maryland, Baltimore County, say these echoes are powered by radiation from the supernova shock wave that blew the star apart some 11,000 years ago. "We're seeing the supernova's first flash," Dwek says.


    The Cassiopeia A supernova's first flash of radiation makes clumps of dust unusually hot. Credit: NASA/JPL-Caltech/E. Dwek and R. Arendt
     
    Other Spitzer researchers discovered hot spots near the Cassiopeia A supernova remnant and recognized their importance as light echoes of the original blast. Dwek and Arendt used Spitzer data to probe this hot dust and pin down the cause of the echoes more precisely.

    Six knots of silicate dust near the remnant show temperatures between -280° and -190° Fahrenheit. Although this might seem frigid by Earthly standards, such temperatures are downright hot compared to typical interstellar dust.

    Writing in the October 1 issue of The Astrophysical Journal, the scientists show that the only event that could make the grains this hot is the powerful and short-lived pulse of ultraviolet radiation and X-rays that heralded the death of the star. The flash was a hundred billion times brighter than the sun but lasted only a day or so.

    "They've identified the precise event during the demolition of the star that produces the echo we see," says Michael Werner, the Project Scientist for Spitzer at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

    Light from the explosion reached Earth in the 17th century, but no one noticed. The Spitzer find gives astronomers a second chance to study the supernova as it unfolds.

    Although the explosion originally escaped detection, its aftermath -- a hot, expanding gas cloud known as Cassiopeia A (Cas A, for short) -- is one of the best-studied supernova remnants. The blast zone lies 11,000 light-years away in the constellation Cassiopeia.

    When a massive star runs out of nuclear fuel, its core collapses into a superdense, city-sized object called a neutron star. As the neutron star forms, it stiffens and rebounds. This triggers a mammoth shock wave that blows the star's outer layers to smithereens. The exiting shock creates a high-energy flash that precedes the supernova's rise in visible light.

    Evidence for a flash associated with this "shock breakout" existed only in computer simulations until January 9, 2008. That's when NASA's Swift satellite detected a 5-minute-long X-ray pulse from galaxy NGC 2770. A few days later, a new supernova -- designated SN 2008D -- appeared in the galaxy.

    The infrared echoes from Cas A arise from dust clouds about 160 light-years farther away than the remnant. The supernova's initial radiation pulse expands through space at the speed of light, then encounters the clouds and heats their dust grains. The dust, in turn, reradiates the energy at infrared wavelengths.

    The breakout radiation took 160 years to reach the clouds and, once heated, the dust's infrared energy had to make up the same distance. This extra travel time results in a 320-year offset between the supernova's initial outward-moving flash and arrival of the dust's infrared echo at Earth. The researchers plan to use the echoes to paint an intimate portrait of the explosion, the star, and the immediate environment.

    Light from the Cas A supernova first reached Earth in the late 1600s, but no one back then reported seeing a new star. On August 16, 1680, the English astronomer John Flamsteed might have seen the supernova without recognizing it. He recorded a faint naked-eye star near the position of Cas A, but none exists there now.

    NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA.

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    Lucimary Vargas
    Observatório Astronômico Monoceros
    Além Paraíba-MG-Brasil

    Cosmic 'dark flow' detected across billions of light years

    NASA-GSFC NEWS RELEASE
    Posted: September 23, 2008

    WASHINGTON -- Using data from NASA's Wilkinson Microwave Anisotropy Probe (WMAP), scientists have identified an unexpected motion in distant galaxy clusters. The cause, they suggest, is the gravitational attraction of matter that lies beyond the observable universe.


    Galaxy clusters like 1E 0657-56 (inset) seem to be drifting toward a 20-degree-wide patch of sky (ellipse) between the constellations of Centaurus and Vela. Credit: NASA/WMAP/A. Kashlinsky et al.
     
    "The clusters show a small but measurable velocity that is independent of the universe's expansion and does not change as distances increase," says lead researcher Alexander Kashlinsky at NASA's Goddard Space Flight Center in Greenbelt, Md. "We never expected to find anything like this."

    Kashlinsky calls this collective motion a "dark flow" in the vein of more familiar cosmological mysteries: dark energy and dark matter. "The distribution of matter in the observed universe cannot account for this motion," he says.

    Hot X-ray-emitting gas in a galaxy cluster scatters photons from the cosmic microwave background. Clusters don't precisely follow the expansion of space, so the wavelengths of scattered photons change in a way that reflects each cluster's individual motion.

    This results in a minute shift of the microwave background's temperature in the cluster's direction. Astronomers refer to this change as the kinematic Sunyaev-Zel'dovich (SZ) effect.

    A related distortion, known as the thermal SZ effect, has been observed in galaxy clusters since the 1980s. But the kinematic version is less than one-tenth as strong and has not been detected in any cluster.

    In 2000, Kashlinsky and Fernando Atrio-Barandela from the University of Salamanca, Spain, showed that astronomers could, in essence, amplify the effect isolating the kinematic SZ term. The trick, they found, is to study large numbers of clusters.

    The astronomers teamed up with Dale Kocevski at the University of California, Davis, and Harald Ebeling from the University of Hawaii to identify some 700 X-ray clusters that could be used to find the subtle spectral shift. This sample includes objects up to 6 billion light-years - or nearly half of the observable universe - away.

    Using the cluster catalog and WMAP's three-year view of the microwave background, the astronomers detected bulk cluster motions of nearly 2 million miles per hour. The clusters are heading toward a 20-degree patch of sky between the constellations of Centaurus and Vela.

    What's more, this motion is constant out to at least a billion light-years. "Because the dark flow already extends so far, it likely extends across the visible universe," Kashlinsky says.

    The finding flies in the face of predictions from standard cosmological models, which describe such motions as decreasing at ever greater distances.

    Cosmologists view the microwave background - a flash of light emitted 380,000 years after the big bang - as the universe's ultimate reference frame. Relative to it, all large-scale motion should show no preferred direction.

    Big-bang models that include a feature called inflation offer a possible explanation for the flow. Inflation is a brief hyper-expansion early in the universe's history. If inflation did occur, then the universe we can see is only a small portion of the whole cosmos.

    WMAP data released in 2006 support the idea that our universe experienced inflation. Kashlinsky and his team suggest that their clusters are responding to the gravitational attraction of matter that was pushed far beyond the observable universe by inflation. "This measurement may give us a way to explore the state of the cosmos before inflation occurred," he says.

    The next step is to narrow down uncertainties in the measurements. "We need a more accurate accounting of how the million-degree gas in these galaxy clusters is distributed," says Atrio-Barandela.

    "We're assembling an even larger and deeper catalog of X-ray clusters to better measure the flow," Ebeling adds. The researchers also plan to extend their analysis by using the latest WMAP results, released in March.

    The results will appear this week in the electronic edition of Astrophysical Journal Letters.
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    Lucimary Vargas
    Observatório Astronômico Monoceros
    Além Paraíba-MG-Brasil

    Opportunity's Mad Dash

    Someone once said, "Opportunity knocks only once, but temptation bangs on your door for years." And ever since NASA plopped twin rovers onto the ruddy surface of Mars in early 2004, mission scientists have exploited the longevity of their mechanical marvels to explore ever-wider swaths of Martian real estate.

    Endeavour crater from orbit
    An orbital view of Victoria crater, which Opportunity explored for more than a year, and much larger Endeavour crater, where the rover is now headed. Endeavour is about 14 miles (22 km) across and 1,000 feet (300 m) deep. This scene is a mosaic of about 50 images captured by the THEMIS instrument aboard Mars Odyssey.
    NASA / JPL / Arizona State Univ.
    The rover Opportunity, in particular, recently wrapped up an entire year of scientific prospecting along the rocky inner slopes of Victoria crater — after rolling 4 miles (6 km) to get there. Measuring 2,400 feet across and about a tenth as deep, Victoria provided a ready-made "road cut" in the upper crust that allowed geologists to peer back into recent Martian history.

    Now rover-meister Steven Squyres wants to dispatch Opportunity on an even more audacious undertaking: a 7-mile (12-km) trek to an even larger crater named Endeavour. It's about as far away as the entire distance that the rover has traveled to date, and the craft is already well past its 90-day warranty.

    But reaching (or even nearing) 14-mile-wide Endeavour would provide a scientific boon, since the impact that created it undoubtedly unearthed countless rocks from deep crustal layers and lobbed them onto the surrounding terrain. Squyres also points out that heading south, toward that big pit, is where Opportunity would be heading next anyway.

    The craft is in excellent shape, though there's a balky motor in the shoulder joint of its instrument-tipped robotic arm. And it'll have two advantages that should make the going easier. One is the eagle-eyed Mars Reconnaissance Orbiter, whose High Resolution Imaging Science Experiment (HiRISE) camera can record surface details smaller than the rover itself. The other is new onboard programming that helps the both rovers optimize their routes to avoid hazards such as sand dunes.

    Still, Opportunity will have to hustle to reach Endeavour. Even clipping along at 110 yards per day, engineers estimate that the journey could take two years.

    By the way, NASA's exploration of Mars was featured last week on National Public Radio's "Talk of the Nation: Science Friday." If you missed the broadcast, you can listen to streamed audio here.

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    Lucimary Vargas
    Observatório Astronômico Monoceros
    Além Paraíba-MG-Brasil

    Ulysses reveals Sun is blowing a weaker solar wind

     
    SOUTHWEST RESEARCH INSTITUTE NEWS RELEASE
    Posted: September 23, 2008


    SAN ANTONIO -- Surprising data from NASA's Ulysses spacecraft show that the solar wind -- the continuous outflow of plasma and magnetic fields from the Sun's atmosphere (corona) into interplanetary space -- is only about three fourths as strong as it was a decade ago, during the last interval of low solar activity.


    Artist concept of heliosphere. Credit: NASA/Goddard Space Flight Center Conceptual Image Lab
     
    Since its launch in 1990, Ulysses has completed nearly three polar orbits around the Sun, enabling researchers to observe the three-dimensional structure of the solar wind and heliosphere, or region of space dominated by our Sun, for the first time.

    "This pioneering spacecraft has allowed us to discover new and fascinating things about the Sun's million-mile-per-hour solar wind and how it changes over time," says Dr. David J. McComas, principal investigator of the Solar Wind Observations Over the Poles of the Sun (SWOOPS) experiment onboard Ulysses and senior executive director of the Space Science and Engineering Division at Southwest Research Institute. "To see such a significant and consistent long-term reduction in the solar wind output is really remarkable."

    Over its 18 years in orbit about the Sun, Ulysses has observed the solar wind at both the minimum and maximum phases of the solar activity (or sunspot) cycle. During solar minimum, the wind is well ordered, with a fast, steady wind over the poles and a slow variable wind at lower latitudes; at solar maximum, the solar wind is highly chaotic, with fast and slow wind streams and more frequent coronal mass ejections at all solar latitudes.

    Now, three-quarters of the way through its third orbit, Ulysses is again observing a solar wind structure characteristic of low levels of solar activity. "During the third orbit, we weren't surprised to see a return to a solar minimum configuration," says McComas, "but we were surprised to find that the solar wind is much less powerful than it had been in the previous solar minimum. The wind speed is almost the same, but the density and pressure are significantly lower, and the wind is blowing out about a quarter less hard."

    The strength of the solar wind appears to be determined to a significant degree by where in the solar corona the energy that drives the solar wind is inserted. Energy inserted at low altitudes results in lower pressures and densities, without affecting solar wind speed. Energy inserted at higher coronal altitudes is expected to produce a change in the solar wind speed, which was not observed.

    To determine whether the weaker solar wind is a whole-sun phenomenon, the team compared Ulysses' high-latitude observations with measurements made by the Advanced Composition Explorer spacecraft at low solar latitudes. The data show a close correlation in the dynamic pressure of the wind measured at all latitudes, confirming that the unusually weak outflow is a global phenomenon.

    The effects of the weaker wind will be felt several billion miles beyond the orbit of Pluto, at the farthest limits of the Sun's influence. "The heliosphere is a big bubble that's inflated from the inside by the million-mile-per-hour solar wind blowing out in all directions," says McComas. "The size of the bubble is determined by the balance of pressure of the solar wind pushing from the inside out and the pressure of interstellar space pushing from the outside in. If the solar wind is blowing out a quarter less hard, that means the outer boundaries of the heliosphere must be shrinking. The entire heliosphere must be getting smaller."

    Some variations in the strength of the solar wind aren't unusual. In the early 1990s, the solar wind weakened for some time and regained strength over the following two years. Further observations will determine whether the solar wind continues to lose strength as the Sun moves from the solar minimum back toward maximum. If the strength of the solar wind stays weak, Voyager 1, which is headed outside of our solar system, should reach the edge of the solar system, called the heliopause, earlier than expected and will become the first spacecraft to enter interstellar space.

    Future NASA missions will help resolve some of the intriguing questions brought forth by Ulysses. NASA is scheduled to launch the Interstellar Boundary Explorer (IBEX) spacecraft in October to make the first global images of the outer boundaries of the solar system. IBEX will be able to image interactions in that region caused by a weaker solar wind. In addition, NASA is about to begin development of the Solar Probe mission to fly in close to the Sun and determine what heats its corona and accelerates the solar wind.

    The article "Weaker Solar Wind from the Polar Coronal Holes and the Whole Sun," by McComas, R.W. Ebert, H.A. Elliott, B.E. Goldstein, J.T. Gosling, N.A. Schwadron and R.M. Skoug, was published in Geophysical Research Letters, 35, L18103, doi:10.1029/2008GL034896.

    SwRI is an independent, nonprofit, applied research and development organization based in San Antonio, Texas, with more than 3,300 employees and an annual research volume of more than $501 million.

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    Lucimary Vargas
    Observatório Astronômico Monoceros
    Além Paraíba-MG-Brasil

     

    The Solar Wind Takes a Breather

     
    I've always had a soft spot for an interplanetary pioneer called Ulysses. Built by the European Space Agency, it was launched in 1990 toward Jupiter, where the planet's powerful gravity yanked the craft out of the ecliptic plane and onto a looping path that carries it over and under the Sun every six years.

    Ulysses' solar orbit
    The Ulysses spacecraft, launched in 1990, recently completed its third and final pass over the Sun's polar regions.
    European Space Agency
    The initial mission concept, known as the International Solar Polar Mission, called for two identical craft — one European and one American — to study high-latitude regions of the Sun that can't be studied from Earth. But NASA reneged on its end of the deal, so Ulysses has soldiered on alone.

    Recently it completed its third and final pass over the Sun's poles. That kind of longevity, far exceeding the planned 5-year-long mission, has really paid off. Ulysses's observations show that the solar wind is particularly feeble right now, with just 75% the strength it had a decade ago. In fact it's never been this weak since monitoring began a half century ago.

    Space physicists had expected the flow to tail off, because the Sun's 11-year activity cycle is now at a minimum. But it's got far less punch than that seen during the last minimum. "The wind speed is almost the same, but the density and pressure are significantly lower," notes investigator David McComas (Southwest Research Institute), whose SWOOPS instrument aboard Ulysses has been key to the new finding.

    The solar wind consists of plasma (ionized matter) and entrained solar magnetic field lines that pushed outward from the Sun's atmosphere into interplanetary space. Ulysses had previously shown that the wind comes off the Sun's poles faster and with less turbulence than it does from its midsection. But both the polar and equatorial flows have throttled back to historic lows.

    There'd been earlier hints, in deep-space observations from IMP 8 and Voyager 2, that the solar wind variously ebbed and flowed during a solar cycle. Still, McComas and his colleagues, who detail their results in the September 18th issue of Geophysical Research Letters, don't know why the solar wind is taking a breather. One suspicion: perhaps the outflow is somehow being energized higher up in the Sun's corona, where there's less mass available to push outward into space.

    Earth's magnetosphere (blue lines) protects our planet from space radiation and from the electromagnetic "wind" (at left) that continually flows from the Sun. During episodes of intense solar activity, as depicted here, the solar wind strengthens and can penetrate the magnetosphere more readily, triggering intense auroral displays.
    NASA / Goddard Space Flight Center
    In any case, the low flow means that the gigantic electromagnetic bubble that surrounds the Sun and planets must be shrinking inward and, with it, the solar system's boundary with interstellar space (called the heliopause). Both Voyager spacecraft are nearing this threshhold; they've aleady encountered a shock front inside the heliopause, and if this weak solar wind keeps up, Voyager 1 may find itself popping outside the heliosphere years sooner than expected.

    Meanwhile, Ulysses itself is nearing the end of its historic mission. FLight controllers have been keeping a death watch all year, because the craft's source of heat and power (radioactive plutonium) has dwindled so much that the fuel lines are in imminent danger of freezing.

    I contacted ESA project manager Richard Marsden for an update on the craft's health. "True to its name, Ulysses refuses to give up without a fight," he replied. "We're still getting science data, albeit only a few hours per day." The team has kept the fuel from freezing by firing thrusters every two hours. But the fuel is running low, and the team expects Ulysses to run dry sometime between the end of September and December. "With a bit of luck," Marsden adds, "we'll encounter the slow solar wind once again before then."

    Hang in there, Ulysses!

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    Lucimary Vargas
    Presidente
    Observatório Astronômico Monoceros
    Além Paraíba-MG-Brasil
    observatorio.monoceros@gmail.com

    Haumea: Dwarf-Planet Name Game

    On September 17th, the International Astronomical Union announced that an object in the Kuiper Belt — the fifth solar-system body large enough to qualify as a "dwarf planet" — had been named. It'll be called Haumea (pronounced how-MAY-uh), after the goddess of childbirth and fertility in Hawaiian mythology.

    But there's far more to the story. When it comes to naming Kuiper Belt objects, the IAU typically accommodates whatever's suggested by the discoverer(s). In the case of Haumea, formerly designated 2003 EL61 and now formally numbered minor planet 136108, there's debate — controversy, actually — over who discovered it.

    The shape of Haumea (formerly 2003 EL61) is roughly 1,960 by 1,000 km — making it a fast-rotating squashed football. Its two satellites are Hi'iaka and Namaka.
    NASA, ESA, and A. Feild (STScI)
    Haumea is the name suggested by Michael Brown (Caltech), who together with Chad Trujillo and David Rabinowitz spotted it on December 28, 2004. But Brown didn't report his team's observations right away to the IAU's clearinghouse for such discoveries, the Minor Planet Center in Cambridge, Massachusetts, as he explains on his website. Instead, he and others continued to scrutinize this relatively bright and thus sizable body — learning a month later, for example, that it had a moon. (They eventually found a second moon as well.)

    In July 2005, just as Brown was preparing to announce all this, Spanish astronomers Pablo Santos-Sanz and José Luis Ortiz Moreno sent the MPC some observations of the same object taken two years earlier at little-known Sierra Nevada Observatory. What's become clear since then is that the Spaniards accessed the American team's publicly accessible observing records 39 hours before submitting their discovery claim to the MPC but, they insist, after deducing the existence of 2003 EL61 themselves.

    To recap: Brown's team chanced upon the object first, but the Spanish observers reported its discovery first. There's still bad blood over this, and it's not likely to be resolved soon. For now, the MPC's record for asteroid 136108 lists "Sierra Nevada" as both the discoverer(s) and the discovery site, though those details are omitted from Haumea's official naming citation. But you won't find the discoverers' names listed next to Sierra Nevada (which is apparently how the Spaniards wanted it).

    So why didn't 2003 EL61 get christened Ataecina, the name suggested by Ortiz and his colleagues? Ataecina was a goddess worshiped by ancient inhabitants of the Iberian peninsula, and she was usually associated to Proserpina, Roman goddess of the underworld. Therein lies the problem: by IAU convention, deities of the underworld are reserved for objects in Pluto-like orbits (in resonance with Neptune), which 2003 EL61 is not.

    Brown's team proposed not only Haumea but also Hi'iaka and Namaka (two of Haumea's many children) for the two moons. It all fits together nicely.

    But there's been plenty of behind-the-scenes rancor about how these names gained approval. Two groups, the Working Group for Planetary System Nomenclature and the Committee for Small-Body Nomenclature, were under pressure from IAU general secretary General Secretary Karel van der Hucht to resolve the 2003 EL61 naming issue quickly. However, the CSBN's vote on Haumea ended in a tie or at best a slim majority, depending on who's doing the tallying (some of its members sit on the WGPSN as well).

    Since the IAU wasn't bound to accept the name proposed by either team, one wonders why the WGPSN and CSBN didn't work harder to come up with something more politically neutral.

    Oh, by the way, here's a question for any CSBN or WGPSN members who happen to read this: Is Ceres a dwarf planet? I know that was the IAU's intention when the controversial Pluto votes were cast back in 2006 — but unless I'm missing something, the approved resolutions never mention Ceres.
     

    A 'wild cousin' emerges from family tree of exploding stars

    UNIVERSITY OF CHICAGO NEWS RELEASE
    Posted: October 1, 2008


    Astronomers may have discovered the relative of a freakishly behaving exploding star once thought to be the only one of its kind.

    For more than two decades, astronomers have intensively studied supernova 1987A, an exploding star that had behaved like no other. Instead of growing dimmer with time, 1987A has grown brighter at X-ray and radio wavelengths.


    This composite image shows the central regions of the nearby Circinus galaxy, located about 12 million light years away. Data from NASA's Chandra X-ray Observatory is shown in blue and data from the Hubble Space telescope is shown in yellow, red, cyan and light blue. The blue source near the lower right hand corner of the image is the supernova SN 1996cr, that has finally beenidentified over a decade after it exploded. Credit: X-ray (NASA/CXC/Columbia/F.Bauer et al); Optical (NASA/STScI/UMD/A.Wilson et al.)
     
    A team of astronomers that includes the University of Chicago's Vikram Dwarkadas is asking if supernova 1996cr, discovered by Columbia University's Franz Bauer, is actually the "wild cousin" of supernova 1987A.

    "This may be the second case, after '87a, where we see emission that's increasing dramatically," said Dwarkadas, Senior Research Associate in Astronomy & Astrophysics at Chicago. "Normally, you would expect the emission to decrease over time."

    In a new paper that will appear in the Astrophysical Journal, Bauer, Dwarkadas and five co-authors call 1996cr a potential "wild cousin" of the earlier supernova. "These two look alike in many ways, except this newer supernova is intrinsically 1,000 times brighter," Bauer said.

    Supernova 1996cr is located 12 million light years from Earth in the spiral galaxy Circinus, making it one of the nearest-known exploding stars of the last quarter-century.

    When 1996cr exploded in the mid-1990s, no one noticed. Bauer first detected the object in 2001 using NASA's Chandra X-ray Observatory. Although intrigued by its exceptional qualities, Bauer, then at Pennsylvania State University, and his associates were unable to verify it as a supernova.

    But recently acquired data from the European Southern Observatory's Very Large Telescope in Chile prompted further investigation. After searching archival images from Australia's Anglo-Australian Telescope, Bauer determined that the explosion occurred between Feb. 28, 1995, and March 15, 1996.

    All told, Bauer's team examined data from 18 different telescopes, both orbiting and ground-based, nearly all of it coming from the observatories' Internet archives.

    Most supernovas grow dimmer with the passage of time as they release their energy. But the X-ray and radio emissions from 1987A grew brighter because its shock wave had crashed into a dense cloud of gas and dust. Supernova shock waves initially move at speeds of 10,000 miles or more each second.

    According to the calculations of Dwarkadas and other theoreticians, these interstellar gas clouds form a bubble around stars at least eight times more massive than the sun, possibly the product of smaller upheaval or a lifetime of mass-loss from solar wind emissions that took place before the supernova.

    These wind-blown bubbles, as astronomers call them, are like a balloon: empty in the middle with a shell around the outside. The explosion moves rapidly through the cavity for several years because there's almost nothing to stop it. "Then it hits this dense shell. It slows down and begins to give off a lot of emission," Dwarkadas said.

    Supernovas close enough to be studied in such detail come by only once a decade, Bauer said. "It's a bit of a coup to find SN1996cr in the manner we did, and we could never have nailed it without the serendipitous data taken by all of these telescopes. We've truly entered a new era of 'Internet astronomy,'" he said.

    Co-authors of the paper included Niel Brandt, Penn State; Stefan Immler, NASA Goddard Space Flight Center; Norbert Bartel, York University, Canada; and Michael Bietenholz, York University and Hartebeesthoek Radio Observatory, South Africa. The National Science Foundation, the National Aeronautic and Space Administration, and the European Science Foundation provided funding.

    Sharpening up Jupiter

    EUROPEAN SOUTHERN OBSERVATORY NEWS RELEASE
    Posted: October 2, 2008


    A record two-hour observation of Jupiter using a superior technique to remove atmospheric blur has produced the sharpest whole-planet picture ever taken from the ground. The series of 265 snapshots obtained with the Multi-Conjugate Adaptive Optics Demonstrator (MAD) prototype instrument mounted on ESO's Very Large Telescope (VLT) reveal changes in Jupiter's smog-like haze, probably in response to a planet-wide upheaval more than a year ago.


    Credit: ESO/F. Marchis, M. Wong, E. Marchetti, P. Amico, S. Tordo
    See a larger image here

     
    Being able to correct wide field images for atmospheric distortions has been the dream of scientists and engineers for decades. The new images of Jupiter prove the value of the advanced technology used by MAD, which uses two or more guide stars instead of one as references to remove the blur caused by atmospheric turbulence over a field of view thirty times larger than existing techniques.

    "This type of adaptive optics has a big advantage for looking at large objects, such as planets, star clusters or nebulae," says lead researcher Franck Marchis, from UC Berkeley and the SETI Institute in Mountain View, California, USA. "While regular adaptive optics provides excellent correction in a small field of view, MAD provides good correction over a larger area of sky. And in fact, were it not for MAD, we would not have been able to perform these amazing observations."

    MAD allowed the researchers to observe Jupiter for almost two hours on 16 and 17 August 2008, a record duration, according to the observing team. Conventional adaptive optics systems using a single Jupiter moon as reference cannot monitor Jupiter for so long because the moon moves too far from the planet. The Hubble Space Telescope cannot observe Jupiter continuously for more than about 50 minutes, because its view is regularly blocked by the Earth during Hubble's 96-minute orbit.

    Using MAD, ESO astronomer Paola Amico, MAD project manager Enrico Marchetti and Sébastien Tordo from the MAD team tracked two of Jupiter's largest moons, Europa and Io ­ one on each side of the planet ­ to provide a good correction across the full disc of the planet. "It was the most challenging observation we performed with MAD, because we had to track with high accuracy two moons moving at different speeds, while simultaneously chasing Jupiter," says Marchetti.

    With this unique series of images, the team found a major alteration in the brightness of the equatorial haze, which lies in a 16 000-kilometre wide belt over Jupiter's equator. More sunlight reflecting off upper atmospheric haze means that the amount of haze has increased, or that it has moved up to higher altitudes. "The brightest portion had shifted south by more than 6000 kilometres," explains team member Mike Wong.

    This conclusion came after comparison with images taken in 2005 by Wong and colleague Imke de Pater using the Hubble Space Telescope. The Hubble images, taken at infrared wavelengths very close to those used for the VLT study, show more haze in the northern half of the bright Equatorial Zone, while the 2008 VLT images show a clear shift to the south.

    "The change we see in the haze could be related to big changes in cloud patterns associated with last year's planet-wide upheaval, but we need to look at more data to narrow down precisely when the changes occurred," declares Wong.

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