Terra esquenta mais que o previsto, diz painel da ONU
CLAUDIO ANGELO
Enviado especial da Folha de S.Paulo ao Rio

O aquecimento global está ocorrendo de forma mais rápida do que se imaginava e as temperaturas médias da Terra em 2100 serão ainda mais altas do que previam os cientistas.

Quem diz é o vice-presidente do IPCC, o maior painel de climatologistas do mundo, que daqui a um ano divulgará um relatório com tudo o que a ciência sabe sobre o efeito estufa.

O cingalês Mohan Munasinghe esteve no Brasil participando do simpósio Dimensões Éticas das Mudanças Climáticas, promovido pelo Fórum Brasileiro de Mudanças Climáticas e pela Coppe (Coordenação de Pós-Graduação em Engenharia) da UFRJ e encerrado anteontem no Rio. Ele disse à Folha que o 4º Relatório de Avaliação do IPCC (Painel Intergovernamental sobre Mudança Climática) reduz a incerteza que havia sobre o impacto da ação humana no clima e sobre suas dimensões --como quanto o planeta esquentará, em média, no fim do século.

"Eu não posso dar o valor, porque isso seria revelar o resultado. Mas a previsão anterior foi 3,5ºC, e a nova não deve ser menor que isso. Provavelmente será maior", afirmou.

O último Relatório de Avaliação do painel, divulgado em 2001, estabelece que as temperaturas do planeta em 2100 estarão de 1,5ºC a 5,8ºC mais altas. Ambos os extremos têm probabilidade baixa de acontecer. O cenário mais provável fala em mais de 3ºC, o que já seria suficiente para uma catástrofe global: a essa temperatura, por exemplo, a floresta amazônica entraria em colapso.

Uma versão preliminar do 4º relatório foi obtida pelo Congresso dos EUA e vazou para a imprensa em maio. Ela fala em até 4,5ºC de aumento nas médias globais. Munasinghe afirmou que a confiança nas projeções da temperatura aumentou bastante em relação à avaliação anterior do IPCC, órgão oficial da ONU para o tema aquecimento global, principalmente pelo aperfeiçoamento dos novos modelos climáticos existentes. Além disso, "temos agora um número muito maior de modelos. Isso dá mais confiança no sentido de direção, e alguma confiança sobre o valor médio das temperaturas."

Evidências frias

Segundo o pesquisador, as evidências de aceleração da mudança climática a serem apresentadas pelo IPCC vêm sobretudo de estudos geofísicos, como os que evidenciam o derretimento de geleiras e gelo marinho no Ártico e a aceleração do fluxo de geleiras na calota polar da Antártida ocidental. Nos últimos dois anos, várias pesquisas têm sido publicadas que indicam uma contribuição maior do degelo antártico para a elevação do nível do mar.

"Esses estudos dão essa indicação mesmo antes do quarto relatório", afirmou o cientista.

Criado nos anos 1990 para compilar toda a informação científica sobre o aquecimento global, o IPCC tem sofrido pressões políticas fortes, principalmente da administração dos EUA de George W. Bush --que em 2002 trocou a presidência do painel a pedido da Exxon. Bush acusa o IPCC de ser politicamente enviesado e de ter baixa representação americana -apesar de mais de 40% dos 3.000 cientistas do painel serem americanos.

"É difícil fazer as coisas mesmo sem pressão política num painel desses", afirma o cingalês. Ele diz que as recomendações do 4º Relatório de Avaliação aos governos do mundo todo são simples: "É preciso tomar providências o quanto antes. Deveria haver pressões éticas dos cientistas por um corte maior de emissões. Mas isso não vai acontecer, na minha opinião, porque os países tomam decisões com base em interesses nacionais".

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José Geraldo Mattos

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

 

 

 

 

 

 

New Horizons’ Telescope Sees First Light

September 5th, 2006

Although New Horizons is still more than 9 years away from reaching Pluto, it’s ready to do some science along the way. The spacecraft passed an important milestone this week when it opened the protective cover on its Long Range Reconnaissance Imager (LORRI) and took a photograph of the Messier 7 star cluster. Stars were visible in this cluster down to 12th magnitude, which matches the instrument’s pre-launch calibration. New Horizons will start imaging Jupiter with LORRI as it approaches a Feb. 28, 2007 flyby.

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The highest-resolution camera on NASA’s Pluto-bound New Horizons spacecraft is seeing stars, and mission scientists and engineers couldn’t be more excited.

This week the Long Range Reconnaissance Imager (LORRI) opened its protective cover and took its first image in space, of Messier 7, a star cluster in our Milky Way galaxy. The electronic snapshot also meant that all seven New Horizons science instruments have now operated in space and returned good data since the spacecraft launched in January 2006.

Developed by the Johns Hopkins University Applied Physics Laboratory (APL), which also built and operates the New Horizons spacecraft, LORRI is the long focal length, reflecting telescope on New Horizons, designed to acquire the highest-resolution images of Pluto and its moons during a flyby in summer 2015.

“LORRI is our ‘eagle eyes’ on New Horizons, providing the most detailed images we have,” says New Horizons Principal Investigator Alan Stern, of the Southwest Research Institute (SwRI), Boulder, Colo. “This week’s virtuoso first-light performance by LORRI is the best news any Pluto fan could hope for.”

Operating on commands stored in the spacecraft’s computer, the hinged cover door popped open just after 2:40 a.m. EDT on Aug. 29, and LORRI snapped its first image about five and a half minutes later. Data reached the APL Mission Operations Center in Maryland during a scheduled connection through NASA’s Deep Space Network just after 11 a.m. EDT. First came data that temperatures on the camera were cooling, indicating that the door had opened. Then the image arrived on operators’ screens. “I see stars!” said APL’s Steve Conard, who led the engineering team that built and tested LORRI.

“Our hope was that LORRI’s first image would prove not only that the cover had opened completely, but that LORRI was capable of providing the required high-resolution imaging of Pluto and Charon,” says Andy Cheng, LORRI principal investigator, from APL. “Our hopes were not only met, but exceeded.”

The image shows the center of the famous star cluster Messier 7, which was catalogued by Charles Messier in 1764, and described by Ptolemy around 130 A.D. Stars to at least 12th magnitude are clearly visible, meaning LORRI’s sensitivity and noise levels in space are consistent with its pre-launch calibrations on the ground.

LORRI is a panchromatic high-magnification imager, consisting of a telescope with an 8.2-inch (20.8-centimeter) aperture that focuses visible light onto a charge-coupled device (CCD). It’s essentially a digital camera with a large telephoto telescope, only fortified to operate in the cold, hostile environs near Pluto. LORRI has no color filters or moving parts; operators take images by pointing the LORRI side of the spacecraft at their target. The instrument’s silicon carbide construction kept its mirror focused even after the its temperature plunged by more than 120 degrees F (50 degrees C) once the door opened. LORRI is now approximately at the same temperature it will be when takes close-up images of Pluto nine years from now.

Before then LORRI will focus on the Jupiter system, taking its first pictures of the giant planet on Sept. 4. Next Feb. 28 the spacecraft will pass within 1.4 million miles (2.27 million kilometers) of Jupiter, getting a gravity assist toward Pluto and training its instruments on Jupiter and several jovian moons. While there, LORRI will study many aspects of Jupiter, including the planet’s weather and aurora, its rings, and its fascinating satellite system.
Part of NASA’s New Frontiers Program, New Horizons is the first mission to Pluto and the Kuiper Belt of rocky, icy objects beyond. Dr. Stern leads the mission and science team as principal investigator; SwRI led development of the New Horizons science payload. APL, in Laurel, Md., manages the mission for NASA’s Science Mission Directorate.

SMART-1 Smashed into the Moon

September 3rd, 2006

ESA’s SMART-1 spacecraft ended its productive mission on September 3, 2006 when it crashed into the lunar soil in the “Lake of Excellence” region of the Moon. The impact took place on the near side of the Moon, in full view of Earth and space-based telescopes; even amateurs captured a tiny flash in their telescopes as the spacecraft obliterated, and carved out a small crater. This final act of science will hopefully give researchers some insights into the minerals that lie underneath the lunar surface, which were briefly excavated by the impact.

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Early this morning, a small flash illuminated the surface of the Moon as the European Space Agency’s SMART-1 spacecraft impacted onto the lunar soil, in the ‘Lake of Excellence’ region. The planned impact concluded a successful mission that, in addition to testing innovative space technology, had been conducting a thorough scientific exploration of the Moon for about a year and a half.

SMART-1 scientists, engineers and space operations experts witnessed the final moments of the spacecraft’s life in the night between Saturday 2 and Sunday 3 September at ESA’s European Space Operations Centre (ESOC), in Darmstadt, Germany. The confirmation of the impact reached ESOC at 07:42:22 CEST (05:42:22 UT), when ESA’s New Norcia ground station in Australia suddenly lost radio contact with the spacecraft. SMART-1 ended its journey in the Lake of Excellence, in the point situated at 34.4º South latitude and 46.2º West longitude.

The SMART-1 impact took place on the near side of the Moon, in a dark area just near the terminator (the line separating the day side from the night side), at a “grazing” angle between 5 and 10 degrees and a speed of about 2 kilometres per second. The impact time and location was planned to favour observations of the impact event from telescopes on Earth, and it was achieved by a series of orbit manoeuvres and corrections performed during the course of summer 2006, the last of which was done on 1 September.

Professional and amateur ground observers all around the world – from South Africa to the Canary Islands, South America, the continental United States, Hawaii, and many other locations – were watching before and during the small SMART-1 impact, hoping to spot the faint impact flash and to obtain information about the impact dynamics and about the lunar surface excavated by the spacecraft. The quality of the data and images gathered from the ground observatories – a tribute to the end of the SMART-1 mission and a possible additional contribution to lunar science - will be assessed in the days to come.

For the last 16 months and until its final orbits, SMART-1 has been studying the Moon, gathering data about the morphology and mineralogical composition of the surface in visible, infrared and X-ray light.

“The legacy left by the huge wealth of SMART-1 data, to be analysed in the months and years to come, is a precious contribution to lunar science at a time when the exploration of the Moon is once again getting the world’s interest” said Bernard Foing, ESA SMART-1 Project Scientist. “The measurements by SMART-1 call into question the theories concerning the Moon’s violent origin and evolution,” he added. The Moon may have formed from the impact of a Mars-size asteroid with the Earth 4500 million years ago. “SMART-1 has mapped large and small impact craters, studied the volcanic and tectonic processes that shaped the Moon, unveiled the mysterious poles, and investigated sites for future exploration,” Foing concluded.

“ESA’s decision to extend the SMART-1 scientific mission by a further year ( it was initially planned to last only six months around the Moon) allowed the instrument scientists to extensively use a number of innovative observing modes at the Moon,” added Gerhard Schwehm, ESA’s SMART-1 Mission Manager. In addition to plain nadir observations (looking down on the ‘vertical’ line for lunar surveys), they included targeted observations, moon-spot pointing and ‘push-broom’ observations (a technique SMART-1 used to obtain colour images). “This was tough work for the mission planners, but the lunar data archive we are now building is truly impressive.”

“SMART-1 has been an enormous success also from a technological point of view,” said Giuseppe Racca, ESA SMART-1 Project Manager. The major goal of the mission was to test an ion engine (solar electric propulsion) in space for the first time for interplanetary travel, and capture a spacecraft into orbit around another celestial body, in combination with gravity assist manoeuvres.

SMART-1 also tested future deep-space communication techniques for spacecraft, techniques to achieve autonomous spacecraft navigation, and miniaturised scientific instruments, used for the first time around the Moon. “It is a great satisfaction to see how well the mission achieved its technological objectives, and did great lunar science at the same time,” Racca concluded.

“Operating SMART-1 has been an extremely complex but rewarding task,” said Octavio Camino-Ramos, ESA SMART-1 Spacecraft Operations Manager. “The long spiralling trajectory around Earth to test solar electric propulsion (a low-thrust approach), the long exposure to radiation, the strong perturbations of the gravity fields of the Earth-Moon system and then the reaching of a lunar orbit optimised for the scientific investigations, have allowed us to gain valuable expertise in navigation techniques for low-thrust propulsion and innovative operations concepts: telemetry distribution and alerting through the internet, and a high degree of ground operations automation - a remarkable benchmark for the future,” he explained.

“For ESA’s Science Programme, SMART-1 represents a great success and a very good return on investment, both from the technological and the scientific point of view,” said Professor Southwood, ESA’s Director of Science. “It seems that right now everyone in the world is planning on going to the Moon. Future scientific missions will greatly benefit from the technological and operational experience gained thanks to this small spacecraft, while the set of scientific data gathered by SMART-1 is already helping to update our current picture of the Moon.”

SMART-1, (Small Mission for Advanced Research and Technology) is the first European mission to the Moon. It was launched on 27 September 2003 on board an Ariane 5 rocket, from the CSG, Europe’s Spaceport in Kourou, French Guiana and reached its destination in November 2004 after following a long spiralling trajectory around Earth.

In this phase, the spacecraft successfully tested for the first time in space the series of advanced technologies it carried on board. The technology demonstration part of the mission was declared successfully concluded when SMART-1 reached the Moon and was captured by the lunar gravity field in mid-November 2004.

SMART-1 started its scientific observations of the Moon in March 2005, running on an elliptical polar orbit that ranged from about 500 to 3000 kilometres over the lunar surface. The instruments on board included a miniaturised imaging camera (AMIE), an X-ray telescope (D-CIXS) to identify the key chemical elements in the lunar surface, an infrared spectrometer (SIR) to chart the Moon’s minerals and an X-ray solar monitor (XSM) to complement the D-CIXS measurements and study the solar variability.

SMART-1 was a small unmanned satellite weighing 366 kilograms and roughly fitting into a cube just 1 metre across, excluding its 14-metre solar panels. It was manufactured by the Swedish Space Corporation, Solna (Sweden), leading a consortium of more than 20 European industrial teams.

Original Source: ESA News Release

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Crater Melanthius on Tethys

August 31st, 2006

Cassini took this photograph of the 245-km (150-mile) crater Melanthius on the surface of Saturn’s moon Tethys. The central mountains at the heart of Melanthius are left over from when the crater first formed millions of years ago. Cassini took the photo on July 23, 2006 when it was 120,000 kilometers (75,000 miles) from Tethys.

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Cassini looks into the 245-kilometer (150-mile) wide crater Melanthius in this view of the southern terrain on Tethys. The crater possesses a prominent cluster of peaks in its center which are relics of its formation.

Notable here is a distinct boundary in crater abundance — the cratering density is much higher in the farthest western terrain (left side of the image) than elsewhere.

North on Tethys (1,071 kilometers, or 665 miles across) is up and rotated 45 degrees to the left.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 23, 2006 at a distance of approximately 120,000 kilometers (75,000 miles) from Tethys and at a Sun-Tethys-spacecraft, or phase, angle of 29 degrees. Image scale is 715 meters (2,345 feet) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

Magnetar Crackles with Radio Waves

August 30th, 2006

Astronomers have discovered a rapidly spinning pulsar with a powerful magnetic field - called a magnetar - that’s demonstrating some brand new tricks. Located about 10,000 light years from Earth, this magnetar is sending out powerful pulses of radio waves at regular intervals; normally magnetars are only seen in the X-ray spectrum. The discoverers think that the magnetic field around the star is twisting, causing huge electric currents to flow - these currents are generating the radio pulses.

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Astronomers using radio telescopes from around the world have discovered a spinning neutron star with a superpowerful magnetic field — called a magnetar — doing things no magnetar has been seen to do before. The strange behavior has forced them to scrap previous theories about radio pulsars and promises to give new insights on the physics behind these extreme objects.

The magnetar, approximately 10,000 light-years from Earth in the direction of the constellation Sagittarius, is emitting powerful, regularly-timed pulses of radio waves just like radio pulsars, which are neutron stars with far less intense magnetic fields. Usually, magnetars are visible only in X-rays and sometimes very weakly in optical and infrared light.

“No one has ever found radio pulses coming from a magnetar before. We thought that magnetars didn’t do this,” said Fernando Camilo of Columbia University. “This object is going to teach us new things about magnetar physics that we would never have learned otherwise,” Camilo added.

Neutron stars are the remnants of massive stars that have exploded as supernovae. Containing more mass than the Sun, they are compressed to a diameter of only about 15 miles, making them as dense as atomic nuclei. Ordinary pulsars are neutron stars that emit “lighthouse beams” of radio waves along the poles of their magnetic fields. As the star spins, the beam of radio waves is flung around, and when it passes the direction of Earth, astronomers can detect it with radio telescopes.

Scientists have found about 1700 pulsars since their first discovery in 1967. While pulsars have strong magnetic fields, about a dozen neutron stars have been dubbed magnetars because their magnetic fields are 100-1,000 times stronger than those of typical pulsars. It is the decay of those incredibly strong fields that powers their strange X-ray emission.

“The magnetic field from a magnetar would make an aircraft carrier spin around and point north quicker than a compass needle moves on Earth,” said David Helfand, of Columbia University. A magnetar’s field is 1,000 trillion times stronger than Earth’s, Helfand pointed out.

The new object — named XTE J1810-197 — was first discovered by NASA’s Rossi X-ray Timing Explorer when it emitted a strong burst of X-rays in 2003. While the X-rays were fading in 2004, Jules Halpern of Columbia University and collaborators identified the magnetar as a radio-wave emitter using the National Science Foundation’s (NSF) Very Large Array (VLA) radio telescope in New Mexico. Any radio emission is highly unusual for a magnetar.

Because magnetars had not been seen to regularly emit radio waves, the scientists presumed that the radio emission was caused by a cloud of particles thrown off the neutron star at the time of its X-ray outburst, an idea they soon would realize was wrong.

With knowledge that the magnetar emitted some form of radio waves, Camilo and his colleagues observed it with the Parkes radio telescope in Australia in March and immediately detected astonishingly strong radio pulsations every 5.5 seconds, corresponding to the previously-determined rotation rate of the neutron star.

As they continued to observe XTE J1810-197, the scientists got more surprises. Whereas most pulsars become weaker at higher radio frequencies, XTE J1810-197 does not, remaining a strong emitter at frequencies up to 140 GHz, the highest frequency ever detected from a radio pulsar. In addition, unlike normal pulsars, the object’s radio emission fluctuates in strength from day to day, and the shape of the pulsations changes as well. These variations likely indicate that the magnetic fields around the pulsar are changing as well.

What’s causing this behavior? At the moment, the scientists believe that the magnetar’s intense magnetic field is twisting, causing changes in the locations where huge electric currents flow along the magnetic-field lines. These currents likely generate the radio pulsations.

“To solve this mystery, we’ll continue monitoring this crazy object with as many telescopes as we can get our hands on and as often as possible. Hopefully, seeing all these changes with time will give us a deeper understanding of what is really going on in this very extreme environment,” said team member Scott Ransom of the National Radio Astronomy Observatory.

Because they expect that XTE J1810-197 will fade at all wavelengths, including the radio, the scientists also have observed it with the NSF’s Robert C. Byrd Green Bank Telescope and Very Long Baseline Array (VLBA), Parkes and the Australia Telescope Compact Array in Australia, the IRAM telescope in Spain, and the Nancay Observatory in France. John Reynolds and John Sakissian of Parkes Observatory, Neil Zimmerman of Columbia University and Juan Penalver and Aris Karastergiou of IRAM also are members of the research team. The scientists reported their initial findings in the August 24 issue of the scientific journal Nature.

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Original Source: NRAO News Release

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Estudo confirma parentesco entre asteróides e meteoritos 09/09/2006 Estadão - Asteróides e meteoritos são feitos dos mesmo materiais: ao menos, é o que os professores dizem a seus alunos há décadas. Mas, até recentemente, os dados não se encaixavam exatamente nessa história: quando os cientistas comparavam a luz infravermelha refletida pelos asteróides (medida a partir da Terra) com a dos meteoritos (coletados na Terra), apareciam diferenças suficientes para levantar dúvidas sobre se os asteróides poderiam mesmo ser a fonte das pedras que acém do céu. Leia também: Cientista diz ter encontrado "células-alien" Uma nova comparação, detalhada, do asteróide Itokawa e amostras de meteorito confirma que o processo de erosão no espaço pode explicar a diferença nos padrões de reflexão entre asteróides e condritos, como é conhecida a classe mais comum de meteorito. "Eles (meteoritos condríticos) são tão abundantes, têm tantas fontes nos asteróides, mas nunca conseguimos encontrar nenhum que batesse tão claramente. Estas observações realmente nos deixam ver a erosão espacial em ação", disse Takahiro Hiroi, principal autor do artigo sobre o assunto, publicado na revista Nature. Ao longo de milhões de anos, o fluxo de íons de alta energia e de partículas microscópicas que existe no espaço vaporiza a superfície dos asteróides, depositando uma camada fina que altera as propriedades ópticas desses corpos celestes.

 

 

 

 

 

 

Missão espacial vai investigar explosões do Sol 11/09/2006 Yahoo - Cientistas vão lançar uma nova missão espacial no final deste mês para estudar as mais violentas explosões do sistema solar. Por meio da monitoração dos campos magnéticos do Sol, a missão Solar-B --uma parceria de britânicos, japoneses e norte-americanos para descobrir mais sobre chamas solares (estouros de energia equivalentes à explosão de dezenas de milhões de bombas de hidrogênio em uma questão de minutos. "O que queremos é explorar as explosões mais energéticas do sistema solar, então podemos realmente prever quando elas irão ocorrer e porque elas ocorrem", afirmou o professor Louise Harra, do Laboratório de Ciência Espacial Mullard, da Universidade College London, durante conferência científica. Os instrumentos da espaçonave vão medir os movimentos dos campos magnéticos e observar como a atmosfera do Sol responde a eles. A missão vai se focar na fase de explosão das chamas solares. As chamas solares ocorrem quando a energia armazenada em campos magnéticos retorcidos é subitamente liberada. As maiores chamas ocorrem onde estão os maiores campos magnéticos. As chamas são geralmente associadas com as manchas solares, áreas escuras causadas pelo impacto de intensos campos magnéticos na superfície do sol. Elas representam perigo aos astronautas e espaçonaves e podem causar falhas em transmissão de satélites, redes elétricas e redes de telefones celulares na Terra. A Solar B deverá ser lançada em 22 de setembro a partir do centro espacial de Uchinoura, no sul do Japão, e sua missão tem prazo de três anos. Harra afirmou que um melhor entendimento das chamas solares pode fornecer informação sobre como os campos magnéticos liberam grandes montantes de energia e se pode existir vida em outros lugares do universo.

 

 

 

 

 

 

Estudo revela probabilidade de planetas parecidos com a Terra 11/09/2006 Yahoo - A existência de planetas semelhantes à Terra em outras galáxias, com ambientes que poderiam dar origem à vida, é muito mais provável do que se imaginava até agora, segundo revela um estudo divulgado hoje na revista "Science". A pesquisa, realizada por cientistas das universidades do Colorado e da Pensilvânia, indica que mais de um terço dos gigantescos conjuntos planetários identificados fora de nosso sistema solar podem abrigar corpos semelhantes à Terra. Segundo os cientistas, muitos deles contam com oceanos nos quais poderia haver condições para o desenvolvimento de algum tipo de vida. "Agora acreditamos que existe em outros sistemas solares um novo tipo de planetas cobertos por oceanos que possivelmente são habitáveis", indica no relatório sobre o estudo Sean Raymond, pesquisador da Universidade do Colorado. O cientista assinala que a pesquisa se concentra em um sistema planetário, muito diferente de um sistema solar, que contém gigantes gasosos conhecidos como "Júpiteres incandescentes", que orbitam muito perto de suas estrelas. Até hoje, os especialistas supunham que os "Júpiteres incandescentes" arrastavam consigo material protoplanetário, que era expulso do sistema. "Mas os modelos indicam que é provável que estas idéias estivessem equivocadas", afirmou Raymond. Os pesquisadores chegaram à conclusão de que provavelmente há planetas semelhantes por meio de simulações digitais que trabalhavam com discos protoplanetarios teóricos com mais de mil corpos de rochas, gelo e até de luas. As condições iniciais de cada modelo se basearam nas teorias sobre a formação de planetas no sistema solar ao longo de 200 milhões de anos de evolução. Segundo Raymond, o grupo de pesquisadores determinou, graças a esse estudo, que um de cada três sistemas planetários pode ter evoluído em "zonas habitáveis" como a Terra. Além disso, as simulações mostraram que planetas rochosos, conhecidos como "Terras incandescentes", com freqüência se formam dentro da órbita dos "Júpiteres incandescentes". O estudo lembra que uma equipe da Universidade da Califórnia descobriu no ano passado uma "Terra incandescente" que tem um raio duas vezes maior do que o de nosso planeta, e que orbita a não mais do que 3,6 milhões de quilômetros de sua estrela. Segundo Raymond, as simulações mostraram que os planetas similares à Terra se formaram com grandes quantidades de água e provavelmente continham uma pequena percentagem de ferro, elemento importante na evolução e possível oxigenação de uma atmosfera parecida com a nossa. Além disso, afirmou que as "Terras incandescentes" podem se formar muito rápido, em apenas 100 mil anos. Segundo os geólogos, a Terra passou de seu estado gasoso ao sólido e à sua formação definitiva entre 30 e 50 milhões de anos atrás. "Definitivamente, acredito que há planetas habitáveis", indicou o cientista. No entanto, advertiu que "qualquer tipo de vida nesses planetas poderia ser muito diferente da nossa". "Há muitos passos evolutivos entre a formação destes planetas em outros sistemas e a presença de formas de vida", afirmou. Segundo a equipe de cientistas, cujo trabalho foi financiado pelo Instituto de Astrobiologia da Nasa, a pesquisa poderia ajudar os "caçadores de planetas" a determinar os parâmetros para sua busca. "As próximas missões espaciais ajudarão a descobrir e descrever planetas similares à Terra que giram em torno de outras estrelas", dizem os autores do estudo. Eles se atrevem a afirmar que será descoberto "que uma grande parte dos sistemas de planetas gigantes contam com `Terras incandescentes´ ou potencialmente habitáveis, com planetas ricos em água e em órbitas estáveis".

 

 

 

 

 

 

Amazônia tem novo vigia a partir desta segunda CLAUDIO ANGELO
editor de Ciência da Folha de S. Paulo

Se a Amazônia acabar de fato, não há de ser por falta de vigilância. Uma organização de pesquisas de Belém lança hoje o primeiro sistema independente para monitorar o desmatamento em tempo real, por meio de imagens de satélite. A idéia é ter informações sobre a devastação da floresta disponíveis na internet e atualizadas todo mês --não só para diagnosticar a situação da floresta mas também para prever desmatamentos futuros.

O SAD (Sistema de Alerta de Desmatamento), como foi batizada a ferramenta, é uma criação de uma equipe do Instituto do Homem e Meio Ambiente da Amazônia, o Imazon. Ele deve permitir o cálculo mensal da área devastada na região Norte, uma cifra que o governo brasileiro hoje só divulga uma vez por ano --o último dado oficial, referente a 2004-2005, saiu na terça-feira passada, confirmando uma queda prevista de 31,5% na taxa de destruição.

"Assim como a inflação, que tem vários índices, esperamos ter o dado mensal do desmatamento como um indicador a mais", compara Adalberto Veríssimo, pesquisador do Imazon e um dos criadores do SAD.

A analogia é mais do que justificada. Afinal, o que os números do desmatamento divulgados anualmente pelo Inpe (Instituto Nacional de Pesquisas Espaciais) medem é a perda de um ativo econômico, cujo valor --em forma de seu estoque de carbono, vital para a regulação do clima-- agora começa a ser reconhecido pelo governo.

Foi justamente para monitorar as emissões de carbono causadas pelo desmatamento que o SAD foi concebido, com uma doação de R$ 200 mil da Fundação Packard. "Nós precisávamos de um sistema independente de acompanhamento, porque os dados do Deter não tinham muita regularidade", diz Carlos Souza Jr., que desenvolveu a metodologia de processamento de imagens do sistema do Imazon.

O Deter é o sistema de detecção do desmatamento em tempo real do governo, criado pelo Inpe a pedido do Ministério do Meio Ambiente. Ele usa imagens dos satélites americanos Modis para monitorar a floresta e guiar a fiscalização do Ibama sobre desmates ilegais.

O Deter foi criado em 2004 com a promessa de ter dados atualizados de desmatamento na internet todo mês, mas isso nunca aconteceu. O sistema também tem baixa resolução --ele foi feito para ser ágil e não preciso, e só consegue "enxergar" desmatamentos acima de 20 hectares devido a uma limitação do Modis. Por isso o Inpe não o utiliza para calcular a área total desmatada, embora o governo o tenha utilizado para avaliar tendências de desmatamento.

Cego que vê

O novo sistema do Imazon usa as mesmas imagens que o Deter, mas processadas de outra forma. Isso amplia sua capacidade de detecção para desmatamentos acima de 5 hectares. O SAD também permite estimar, pela visualização de pequenos desmatamentos, onde o corte raso da floresta tende a acontecer --e fazer alertas.

O primeiro teste do SAD foi feito em Mato Grosso. Até o fim do ano, toda a Amazônia deve ser coberta. Hoje, o Imazon a ONG mato-grossense ICV divulgam um boletim com uma análise da situação do Estado em 2004-2005 e em 2005-2006. O número do SAD para este biênio é de 6.086 km2 desflorestados, algo próximo dos 5.450 km2 medidos pelo Deter. O boletim "Transparência Florestal Mato Grosso" está na internet (www.imazon.org.br).

Outro lado

O coordenador de Monitoramento Ambiental da Amazônia no Inpe, Dalton Valeriano, elogiou o novo sistema do Imazon.

"É mais do que bem-vindo um levantamento paralelo de desmatamento. Será uma oportunidade para aprimorarmos o Deter."

Apesar de as imagens de satélite serem atualizadas a cada duas semanas, hoje o Deter ainda usa identificação visual, para garantir que os fiscais do Ibama não dêem de cara com um alarme falso. Isso torna o processamento mais demorado. Valeriano reconhece há problema nas atualizações mensais do Deter na internet (www.obt.inpe.br/deter). "Isso é falha nossa. O Deter é feito para servir ao Ibama, e a demanda por dados dele é maior do que eu imaginava". O Inpe promete resolver o problema.

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Novo sistema do Ibama já sofre fraudes

Governo registra queda na taxa de desmatamento da Amazônia

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Céu claro pra todos!

 

José Geraldo Mattos

Moderador

 

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

 

 

 

 

 

 

11/09/2006 - 08h28

Atlantis acopla-se com sucesso à Estação Espacial Internacional

da Folha Online

O ônibus espacial Atlantis acoplou-se nesta segunda-feira com sucesso à Estação Espacial Internacional (ISS, em inglês). A chegada marca o reinício da construção da estação, interrompida desde o acidente do Columbia, em 2003.

A tripulação de seis astronautas vai fazer a instalação de dois módulos, de uma antena solar e de geradores que permitirão dobrar a capacidade energética da ISS.

Os astronautas levaram 16 toneladas de equipamentos na espaçonave. O objetivo da Nasa (agência espacial americana) é que a estação fique pronta até 2010.

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Confira a ficha técnica da missão do ônibus espacial Atlantis

Imagens mostram que pedaços de espuma não danificaram o Atlantis

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Fonte:http://www1.folha.uol.com.br/folha/ciencia/ult306u15167.shtml

 

Céu claro pra todos!

 

José Geraldo Mattos

Moderador

 

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

 

 

 

 

 

 

Transístor molecular: cientistas criam transistores de uma única molécula 11/09/2006 Inovação Tecnológica - Cientistas da Universidade do Arizona, Estados Unidos, descobriram como transformar moléculas individuais em transistores. É mais um caminho rumo aos computadores do futuro, já que estamos nos aproximando rapidamente dos limites físicos da atual tecnologia da eletrônica. Os pesquisadores já apresentaram um pedido de patente para o seu Transístor de Efeito de Interferência Quântica, batizado de QuIET ("Quantum Interference Effect Transistor"). A imagem mostra uma concepção artística do novo transístor QuIET. As esferas coloridas representam átomos individuais de carbono (verdes), hidrogênio (violetas) e enxofre (amarelas). As três estruturas douradas representam os contatos metálicos do novo transístor. Uma voltagem aplicada no eletrodo à esquerda controla o fluxo de corrente entre os outros dois. O transístor é a base de toda a eletrônica atual, do radinho de pilha ao computador mais moderno. Esse componente semicondutor é essencialmente uma chave, capaz de ligar e desligar a passagem de uma corrente. Os transistores com que são feitos os chips de computador mais modernos têm 65 nanômetros de comprimento e acredita-se que eles não possam ser construídos menores do que 25 nanômetros. Um transístor molecular, como o QuIET, poderá medir apenas 1 nanômetro. Os transistores atuais desligam a corrente elétrica criando uma barreira energética. Já no transístor molecular, os cientistas utilizaram elementos da mecânica quântica para fazer isso, explorando a combinação dos elétrons enquanto ondas. A molécula mais simples com que poderia ser construído um transístor assim seria o benzeno, uma molécula em forma de anel. Os cientistas propõem inserir dois eletrodos no anel do benzeno, formando dois caminhos para a corrente elétrica. "Na física clássica, as duas correntes passando em cada braço do anel simplesmente se somam," explica o cientista Charles Stafford. Mas, na mecânica quântica, as duas ondas eletrônicas interferem uma com a outra destrutivamente, de forma que não passa nenhuma corrente. Este é o estado desligado do transístor." Alterando-se a fase das ondas, é possível alterar esse padrão de interferência e permitir que a corrente flua, deixando o transístor ligado. Os cientistas levaram cerca de duas semanas para fazer os cálculos básicos. "Mas levará algum tempo para considerar todas as interações eletrônicas que demonstrem que este é realmente um dispositivo robusto," alerta Stafford. O cientista afirma que os dados mostram que leva cerca de 12 anos para que uma idéia inicialmente publicada em um periódico científico se transforme em um produto comercial.

 

 

 

 

 

 

Imagens mostram que pedaços de espuma não danificaram o Atlantis da Efe, em Washington

Os astronautas da Nasa não detectaram dano algum no corpo do ônibus espacial Atlantis durante a inspeção realizada neste domingo com sensores e câmeras acoplados a um braço robótico da nave, informou hoje a agência espacial dos EUA.

Em seu primeiro dia no espaço, os astronautas a bordo do Atlantis usaram o braço para ver se os pedaços de espuma que soltaram durante o lançamento causaram danos à fuselagem da nave.

Segundo a Nasa, era necessário ter certeza de que os pedaços de gelo e da espuma isolante que cobre o tanque externo de combustível da nave, os quais se soltaram pouco mais de quatro minutos após a decolagem de ontem, não a tinham danificado.

Em entrevista coletiva, o diretor de vôo do Atlantis, Paul Dye, disse que as imagens indicam, após uma primeira avaliação, que não há algum dano aparente.

"Temos que analisar as imagens, mas o que vimos é bom", disse Dye, que acrescentou que a nave receberá sinal verde depois que os dados foram analisados a fundo.

Um pedaço de espuma isolante que se soltou durante o lançamento fez a nave Columbia se desintegrar no dia 1º de fevereiro de 2003 durante seu retorno à Terra, matando seus sete tripulantes.

Um problema similar ocorreu, sem conseqüências, durante o lançamento do Discovery para uma missão na Estação Espacial Internacional (ISS), em julho do ano passado.

Desde então, a Nasa ordena uma inspeção externa da nave 24 horas depois da decolagem.

A missão do Atlantis, com uma tripulação de seis astronautas, durará 11 dias. Durante este período, deverão ser realizados três passeios espaciais.

Leia mais

Confira a ficha técnica da missão do ônibus espacial Atlantis

Especial

Leia o que já foi publicado sobre o Atlantis

Fonte:http://www1.folha.uol.com.br/folha/ciencia/ult306u15165.shtml

 

Céu claro pra todos!

 

José Geraldo Mattos

Moderador

 

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

 

 

 

 

 

 

SMART-1 despenhou-se na Lua

2006-09-08

 

 

 

 

 

 

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Planet or failed star? Hubble finds strange object
SPACE TELESCOPE SCIENCE INSTITUTE NEWS RELEASE
Posted: September 7, 2006

Astronomers using NASA's Hubble Space Telescope have photographed one of the smallest objects ever seen around a normal star beyond our Sun. Weighing in at 12 times the mass of Jupiter, the object is small enough to be a planet. The conundrum is that it's also large enough to be a brown dwarf, a failed star.

This Hubble image shows the brown dwarf candidate, called CHXR 73 B, as the bright spot at lower right. It orbits a red dwarf star, dubbed CHXR 73, which is a third less massive than the Sun. Credit: NASA, ESA and K. Luhman (Penn State University) Download larger image version here

The Hubble observation of the diminutive companion to the low-mass red dwarf star CHXR 73 is a dramatic reminder that astronomers do not have a consensus in deciding which objects orbiting other stars are truly planets -- even though they have at last agreed on how they will apply the definition of "planet" to objects inside our solar system.

Kevin Luhman of Penn State University in University Park, Pa., leader of the team that found the object, called CHXR 73 B, is casting his vote for a brown dwarf. "New, more sensitive telescopes are finding smaller and smaller objects of planetary-mass size," said Luhman. "These discoveries have prompted astronomers to ask the question, are planetary-mass companions always planets?"

Some astronomers suggest that an extrasolar object's mass determines whether it is a planet. Luhman and others advocate that an object is only a planet if it formed from the disk of gas and dust that commonly encircles a newborn star. Our solar system planets formed 4.6 billion years ago out of a dust disk around our Sun.

Brown dwarfs, by contrast, form just like stars: from the gravitational collapse of large, diffuse clouds of hydrogen gas. Unlike stars, brown dwarfs do not have quite enough mass to ignite hydrogen fusion reactions in their cores, which power stars such as our Sun.

CHXR 73 B is 19.5 billion miles from its red dwarf sun. That's roughly 200 times farther than Earth is from our Sun. At 2 million years old, the star is very young when compared with our middle-aged 4.6-billion-year-old Sun.

"The object is so far away from its star that it is unlikely to have formed in a circumstellar disk," Luhman explained. Disks around low-mass stars are about 5 to 10 billion miles in diameter. There isn't enough material at that distance from the red dwarf to create a planet. Theoretical models show that giant planets like Jupiter form no more than about 3 billion miles from their stars.

This is an artist's concept of the red dwarf star CHXR 73 (upper left) and its companion CHXR 73 B in the foreground (lower right) weighing in at 12 Jupiter masses. Credit: NASA, ESA and G. Bacon (STScI) Download larger image version here

Hubble's Advanced Camera for Surveys discovered the object while conducting a survey of free-floating brown dwarfs. Astronomers have found hundreds of brown dwarfs in our galaxy since the first brown dwarfs were spied about a decade ago. Most of them are floating through space and not orbiting stars.

"It is important to study young star systems to understand how small bodies formed. Young brown dwarfs are brighter than older, cooler brown dwarfs. This allows them to be seen even at lower masses, where older dwarfs would still be undetectable," said team member John Wilson of the University of Virginia in Charlottesville.

One way to further settle the uncertainty would be if a disk of dust could be observed around CHXR 73's companion. Like stars, brown dwarfs have circumstellar disks, too. They would be no more than about 2 billion miles in diameter.

NASA's Spitzer Space Telescope has detected disks around several free-floating brown dwarfs. But CHXR 73 B is too close to its star for Spitzer to detect the disk. So astronomers will have to wait for the launch of the James Webb Space Telescope in 2013 to determine if this companion has a disk. The Webb telescope will combine Hubble's sharpness, which is needed for detecting close companions, and Spitzer's infrared sensitivity, which is necessary for seeing cool, dusty disks.

The team's result will appear in the Sept. 20 issue of the Astrophysical Journal.

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Descoberta origem verdadeira das auroras boreais 08/09/2006 Estadão - O brilho da aurora boreal não se deve aos ventos solares, como se achava até agora, mas às "subtempestades" magnéticas, revelou um cientista chinês que participou de uma pesquisa conjunta com Estados Unidos e Europa. Leia outras notícias sobre astronomia "Descobrimos que as auroras causadas por ventos solares são muito fracas e mal podem ser vistas a olho nu. As esplêndidas e coloridas auroras que vemos são causadas na realidade pelas subtempestades magnéticas", disse Cao Jinbin, do Centro de Pesquisa Espacial. A descoberta foi possível graças aos dados recolhidos pelos quatro satélites da Agência Espacial Européia (ESA). Segundo o cientista chinês, o próximo passo será instalar um sistema de controle das auroras, capaz de prever e analisar seus movimentos. A aurora, que deve seu nome à deusa romana do amanhecer, ocorre quando velozes fluxos de prótons e elétrons vindos do Sol são guiados pelo campo magnético da Terra e se chocam com os átomos e moléculas atmosféricos. Suas diversas formas, cores e estruturas têm fascinado durante séculos o ser humano. O fenômeno é mais visível normalmente de setembro a outubro e de março a abril. Conhecida como "boreal" no norte e "austral" no sul, a aurora não é um fenômeno exclusivo da Terra. Outros planetas, como Marte e Saturno, são iluminados também pelo seu brilho.

 

 

 

 

 

 

Storms cover the surface of a water world in this artist’s conception. In the distance, a “hot Earth” and “hot Jupiter” appear close to the setting Sun. New computer simulations suggest such a scenario is plausible. Nahks Tr 'Ehnl [larger image]

September 11, 2006 A series of state-of-the-art computer simulations show that earthlike planets form readily in the wake of a giant planet spiraling in toward its star. The authors of a new study estimate that more than a third of the nearly 200 known stars with giant planets may also harbor watery, Earth-size planets. Forty percent of extrasolar planetary systems discovered so far sport "hot Jupiters" — giant planets that formed far from their star, but which, unlike Jupiter, fell inward for 100,000 years or so before settling into star-hugging orbits smaller than Mercury's. Until now, most astronomers assumed a giant planet elbowing its way through a star's planet-forming dust disk would scatter the material needed to grow earthlike planets, halting further planet formation. Sean Raymond, at the University of Colorado, Boulder, plus Steinn Sigurdsson and Avi Mandell, both at Pennsylvania State University, devoted 8 months of computer time to simulating the impact of a migrating gas giant on subsequent planet formation. Their results appear in the September 8, 2006, issue of Science. They started with a gas and dust disk twice as massive as the one that spawned our solar system, but well within the known range of planet-forming disks. They seeded it with hundreds of planetesimals and Moon- to Mars-size planetary embryos. They then sent a Jupiter-size planet from a distant orbit down to one just a quarter the size of Earth's, and watched what happened for the next 200 million years. Although the giant planet did fling many objects into highly eccentric orbits, gravitational resonances and drag from the protoplanetary disk eventually let planets form. In two of the four simulations, one Earth-mass planet formed inside the giant planet's orbit — a "hot Earth" — while a second formed outside, nestled in the star's habitable zone. "We have these big gas giants very close to the star," says Raymond, "but despite that, we have an earthlike planet around one astronomical unit [the average Earth-Sun distance], where life might develop." A second surprise was the huge amount of water that rained onto the planets. The water took the form of icy, comet-like chunks from the disk's outer reaches. It was enough water to cover the planets to a depth of several miles. "I had no idea there would be so much water," says Raymond. "It opens a new realm of possibilities of where to look for life." Other researchers cautiously support the findings. Richard Nelson, at Queen Mary University of London, says his group's simulations, still in press, show similar results. Still, he and several other experts emphasize that many different simulations will need to be run before we can know just how frequently stars harbor hot Jupiters and warm, wet Earths.

Robert Adler, based in Santa Rosa, California, is the author of Science Firsts: From the Creation of Science to the Science of Creation.

Long-lasting Mars rover nears 'bowl' goal
LOCKHEED NEWS RELEASE
Posted: September 7, 2006

NASA's Mars rover Opportunity is closing in on what may be the grandest overlook and richest science trove of its long mission.

During the next two weeks, the robotic geologist is likely to reach the rim of a hole in the Martian surface wider and deeper than any it has visited. The crater, known as "Victoria," is approximately 750 meters (half a mile) wide and 70 meters (230 feet) deep.

Victoria is the large crater near the bottom of this map. The gold line traces Opportunity's path eastward then southward from "Eagle Crater," where it landed, to Endurance Crater, where it spent six months, and nearly to Victoria. The south end of the line indicates Opportunity's location as of the rover's 930th Martian day, or sol, (Sept. 5, 2006). Credit: NASA/JPL/MSSS/Ohio State University Download larger image version here

Images from NASA's Mars Global Surveyor orbiter show the crater walls expose a stack of rock layers approximately 30 to 40 meters (100 to 130 feet) thick. Opportunity will send back its initial view into the crater as soon as it gets to the rim. Scientists and engineers will use Opportunity's observations from points around the rim to plot the best route for entering the crater.

"Victoria has been our destination for more than half the mission," said Ray Arvidson of Washington University, St. Louis. Arvidson is deputy principal investigator for Opportunity and its twin rover, Spirit. "Examination of the rocks exposed in the walls of the crater will greatly increase our understanding of past conditions on Mars and the role of water. In particular, we are very interested in whether the rocks continue to show evidence for having been formed in shallow lakes."

The NASA rovers have been exploring landscapes on opposite sides of Mars since January 2003. Their prime missions lasted three months. Both rovers are still investigating Mars' rocks, soils and atmosphere after more than 30 months. Opportunity works in a region where rock layers hundreds of meters or yards in thickness cover older, heavily cratered terrain.

"We have a fully functional vehicle with all the instruments working. We're ready to hit Victoria with everything we've got," said Byron Jones, a rover mission manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Though it's still winter in Mars' southern hemisphere, days have begun getting longer again, and Opportunity's power supply from its solar panels is increasing daily.

During its first two months on Mars, Opportunity examined a 30-centimeter (one-foot) stack of rock layers at its landing site inside "Eagle Crater" and found geological evidence that water had flowed across the surface long ago. The rover spent the next nine months driving to and exploring a larger crater, "Endurance." There it examined a stack of exposed layers 7 meters (23 feet) thick. Over the drive from Endurance to Victoria, the rocks tell a history of shallow lakes, drier periods of shifting dunes and groundwater levels that rose and fell. Minerals indicate the ancient water was very acidic.

The much thicker stack of revealed rock layers at Victoria beckons. Arvidson said, "We want to examine the thick section of rocks exposed on the walls in Victoria crater to understand whether the environment that produced these materials was similar to the environment recorded in the rocks that we have seen so far. Is there a record of a different type of deposition? Was there a wet environment that was less acidic, perhaps even more habitable? Where do the layers from Endurance fit in this thicker sequence?"

NASA's Mars Reconnaissance Orbiter reached Mars in March 2006. It will begin its primary science phase in November, offering higher resolution images and mineral mapping than have been possible with previous orbiters. Victoria will be one target for the orbiter. "By combining the data from Opportunity and Mars Reconnaissance Orbiter, we'll be able to do some fantastic coordinated analysis," Arvidson said. Such analysis will enhance the science return of both missions and aid in interpreting orbiter data taken of potential landing sites for future missions elsewhere on Mars.

"It's an amazing accomplishment that Spirit and Opportunity have completed the equivalent of 10 prime missions," said John Callas, rover project manager at JPL. "Each of them shows some signs of aging, though. We can't say how long the rovers will last, but we will push to get the best possible science out of these national treasures as long as they keep operating. Victoria could very well be the most productive and exciting science of the entire mission."

JPL manages the rovers and the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate

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On August 29, 2006, the New Horizons Long Range Reconnaissance Imager (LORRI) opened its launch cover door and took its first image in space, of M7, a star cluster in our Milky Way galaxy. The image shows the center of M7, which Charles Messier catalogued in 1764. NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute [larger image]

September 6, 2006 Launched earlier this year, NASA's New Horizons is scheduled to encounter Pluto in July 2015. With a long way to go, the spacecraft's Long Range Reconnaissance Imager (LORRI) opened its eye on August 29 and captured its first picture in space: M7, an open cluster in the constellation Scorpius. And the New Horizons team couldn't be happier. "Our hope was that LORRI's first image would prove not only that the cover had opened completely, but that LORRI was capable of providing the required high-resolution imaging of Pluto and Charon," explains Andy Cheng, LORRI's Principal Investigator. "Our hopes were not only met, but exceeded." The imager is an 8.2-inch reflector and panchromatic high-magnification camera system aboard New Horizons. LORRI will obtain the highest-resolution images of Pluto and its moons during its flyby in summer 2015. With this successful exercise, all seven of New Horizons' instruments have worked properly in space and provided quality data. "LORRI is our eagle eyes on New Horizons, providing the most detailed images we have," says New Horizons Principal Investigator Alan Stern. "This week's virtuoso first-light performance by LORRI is the best news any Pluto fan could hope for." LORRI's next big photo shoot will be in February 2007 with the jovian system. New Horizons will pass within 1.4 million miles (2.27 million kilometers) of Jupiter, receiving a gravity assist toward Pluto. While there, the New Horizons team will point LORRI toward Jupiter and its moons.

Rings Behind Saturn

September 12th, 2006

In this Cassini photograph, Saturn’s B and C rings pass behind the Ringed Planet. Right at the point where they meet Saturn’s upper atmosphere, they appear to bend slightly. This is caused by refraction, as the light from the rings is bent as it passes through the atmosphere. Cassini took this photo on August 16, 2006 when it was 256,000 kilometers (159,000 miles) from Saturn.

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Saturn’s B and C rings disappear behind the immense planet. Where they meet the limb, the rings appear to bend slightly owing to upper-atmospheric refraction.

Crenulations — irregularly wavy or serrated features — in the planet’s clouds denote the locations of turbulent belt/zone boundaries.

The image was taken using a spectral filter sensitive to wavelengths of infrared light centered at 728 nanometers. The view was obtained with the Cassini spacecraft wide-angle camera on Aug. 16, 2006 at a distance of approximately 256,000 kilometers (159,000 miles) from Saturn. Image scale is 12 kilometers (7 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

Hubble Sees the First Bright Galaxies

September 13th, 2006

A new view from the Hubble Space Telescope shows some of the first bright galaxies to emerge in the Universe, appearing around 13 billion years ago, or 900 million years after the Big Bang. Galaxies like these weren’t visible 700 million years after the Big Bang, so smaller galaxies must have merged together quite rapidly for them to get large and bright. The discoveries were made in the Hubble Ultra Deep Field and the Great Observatory Origins Deep Survey Fields.

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A systematic search for the first bright galaxies to form in the early universe has revealed a dramatic jump in the number of such galaxies around 13 billion years ago. These observations of the earliest stages in the evolution of galaxies provide new evidence for the hierarchical theory of galaxy formation–the idea that large galaxies built up over time as smaller galaxies collided and merged.

Astronomers Rychard Bouwens and Garth Illingworth at the University of California, Santa Cruz, used the Hubble Space Telescope to explore the formation of galaxies during the first 900 million years after the Big Bang. They reported their latest findings in the September 14 issue of the journal Nature.

Deep observations in three dark patches of sky–the Hubble Ultra Deep Field and the Great Observatories Origins Deep Survey fields–gathered the faint light emitted 13 billion years ago by stars in primeval galaxies. Only the brightest galaxies could be detected at such great distances.

“These are the deepest infrared and optical data ever taken. We’re looking at a very early stage in the buildup of galaxies,” said Illingworth, a professor of astronomy and astrophysics at UCSC.

The researchers observed hundreds of bright galaxies at around 900 million years after the Big Bang. But when they looked deeper, about 200 million years earlier in time, they only found one. Relaxing their search criteria a bit turned up a few more candidates, but clearly a lot of changes took place during those 200 million years, Illingworth said.

“The bigger, more luminous galaxies just were not in place at 700 million years after the Big Bang. Yet 200 million years later there were many more of them, so there must have been a lot of merging of smaller galaxies during that time,” he said.

Astronomers can determine when light was emitted from a distant source by its redshift, a measure of how the expansion of the universe stretched the wavelengths of the light as it traveled through space across vast distances. Bouwens, a postdoctoral fellow at UCSC and first author of the Nature paper, developed software to systematically sift through the Hubble data in search of high-redshift galaxies.

The data came from two powerful instruments on Hubble, the Advanced Camera for Surveys (ACS) and the Near Infrared Camera and Multi-Object Spectrograph (NICMOS). The researchers compared the numbers of galaxies detected at a redshift of 7 to 8 (700 million years after the Big Bang) with what they might have expected to find if the population of galaxies then were like the population they had observed at redshift 6 (200 million years later). Depending on the strictness of their selection criteria, they found one galaxy where they would have expected 10, or four where they would have expected 17.

“Our approach provides a very quantitative way of measuring the buildup of structure in the universe, so we can see how fast it changed over time as smaller galaxies merged to form larger ones,” Bouwens said.

The galaxies observed in this survey are much smaller than our own Milky Way and other giant galaxies seen today in the nearby universe. These early galaxies were also ablaze with star formation, emitting bluish light that was shifted to red light during its 13-billion-year journey to Hubble’s sensitive detectors.

“It’s quite amazing that we are able to look back across 13 billion years of time. We’re looking at galaxies that have already evolved from smaller precursors, but it’s only a few hundred million years after the formation of the first stars,” Illingworth said.

If the Milky Way is a galactic senior citizen, then these galaxies are toddlers or preschoolers. For now, researchers are unable to detect the even smaller infant galaxies that must have merged to form these first bright galaxies.

But the seeds of those first galaxies can be seen in the the cosmic microwave background radiation, measured most recently and accurately by the Wilkinson Microwave Anisotropy Probe (WMAP), which shows slight fluctuations of density in a remarkably homogeneous universe about 400,000 years after the Big Bang.

“Very early in the evolution of the universe, everything was very smooth. But over time the universe became more and more clumpy as gravity pulled more matter into the denser areas,” Bouwens said. “Our observations of early galaxies allow us to measure how fast the universe was evolving from smaller to larger clumps.”

Detection of the very first galaxies to form will be possible with the successor to Hubble, the James Webb Space Telescope, currently planned for launch in 2013, Illingworth said. Additional information about the search for the first galaxies is available on the web at http://firstgalaxies.ucolick.org/.

Original Source: UCSC News Release

Polar Ice is Melting Fast

September 13th, 2006

New data gathered by NASA’s QuikScat satellite has found that ice at the Arctic polar ice cap is disappearing rapidly. Just between 2004 and 2005, the spacecraft measured a loss of 14% of the perennial sea ice; ice that normally lasts all year round. This is an amount of ice measuring 720,000 square kilometers (280,000 square miles), an area the size of Texas. Scientists expect that the coverage of perennial sea ice will continue to decrease this year as well.

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NASA data show that Arctic perennial sea ice, which normally survives the summer melt season and remains year-round, shrunk abruptly by 14 percent between 2004 and 2005. According to researchers, the loss of perennial ice in the East Arctic Ocean was even higher, nearing 50 percent during that time as some of the ice moved from the East Arctic to the West.

The overall decrease in winter Arctic perennial sea ice totals 720,000 square kilometers (280,000 square miles) — an area the size of Texas. Perennial ice can be 3 or more meters (10 or more feet) thick. It was replaced by new, seasonal ice only about 0.3 to 2 meters (one to seven feet) thick that is more vulnerable to summer melt.

The decrease in the perennial ice raises the possibility that Arctic sea ice will retreat to another record low extent this year. This follows a series of very low ice-cover years observed over the past four summers from active and passive microwave satellite data.

A team led by Son Nghiem of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., used NASA’s QuikScat satellite to measure the extent and distribution of perennial and seasonal sea ice in the Arctic. While the total area of all the Arctic sea ice was stable in winter, the distribution of seasonal and perennial sea ice changed significantly.

“Recent changes in Arctic sea ice are rapid and dramatic,” said Nghiem. “If the seasonal ice in the East Arctic Ocean were to be removed by summer melt, a vast ice-free area would open up. Such an ice-free area would have profound impacts on the environment, as well as on marine transportation and commerce.”

The researchers are examining what caused the rapid decrease in the perennial sea ice. Data from the National Centers for Environmental Prediction, Boulder, Colo., suggest that winds pushed perennial ice from the East to the West Arctic Ocean (primarily located above North America) and significantly moved ice out of the Fram Strait, an area located between Greenland and Spitsbergen, Norway. This movement of ice out of the Arctic is a different mechanism for ice shrinkage than the melting of Arctic sea ice, but it produces the same results - a reduction in the amount of perennial Arctic sea ice.

Researchers indicate that if the sea ice cover continues to decline, the surrounding ocean will get warmer, further accelerating summer ice melts and impeding fall freeze-ups. This longer melt season will, in turn, further diminish the Arctic ice cover.

Nghiem cautioned the recent Arctic changes are not well understood and many questions remain. “It’s vital that we continue to closely monitor this region, using both satellite and surface-based data,” he said.

This is one of three sea ice study results being released today by NASA. These findings are the result of a new study by NASA; the U.S. Army Cold Region Research and Engineering Laboratory, Hanover, N.H.; and the National Ice Center, Washington, D.C. Study results are published in a recent issue of Geophysical Research Letters.

Original Source: NASA/JPL News Release

First Female Space Tourist Will Participate in Several Experiments

September 12th, 2006

The International Space Station is going to be a busy place. Right after Atlantis undocks, the next Soyuz mission, carrying the crew of Expedition 14, as well as a space tourist will launch on September 18. Iranian-American entrepreneur Anousheh Ansari will live on board the station for a week, partly as a tourist, and partly as a test subject for several research experiments. Four experiments are planned for Ansari, including two that test her blood, one to seek the cause of astronaut low-back pain, and a search for bacteria around the station.

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Scheduled to lift off on 18 September 2006 from the Baikonur Cosmodrome, Kazakhstan, along with Expedition 14 crew members, NASA astronaut Michael Lopez-Alegria and Russian cosmonaut Mikhail Tyurin, Iranian-American entrepreneur Anousheh Ansari will be the test subject for four ESA experiments during her stay on board the International Space Station.

The experiments in which Ansari will participate are in the area of human physiology: from the search of the effects of space radiation on the crew, to the investigation of the mechanisms governing the development of muscle atrophy in astronauts. The experiments aim to investigate the reaction of the human organism to the space environment, with the ultimate objective of optimizing the conditions for human permanence in space, and to cast light on common diseases affecting people on Earth.

The European Experiment Programme that is currently carried out by ESA on the International Space Station (ISS) covers a large range of scientific disciplines, which encompass physics, chemistry, biology, physiology, psychology and related topics.

Astronauts on the ISS perform experiments every day
Astronauts on board the ISS have a very busy schedule, performing every day experiments on behalf of scientists on Earth, and acting as subjects of experiments themselves.

A number of experiments - especially in the area of human physiology - fall under a long-term plan and require a high number of observations to be carried out in various sessions and on a considerable number of different subjects. For this reason such experiments involve not only the permanent crew of the ISS, currently constituting three members, but also short term visitors, who are regularly ferried to the Station with the Soyuz or with the Shuttle.

This is the case for ESA astronauts, who normally perform a series of experiments during their short missions to the ISS. In 2005, it was Spaceflight Participant Gregory Olsen who acted as a subject for ESA experiments in the frame of an agreement between ESA and Space Adventures, the company who organises the participation to spaceflight missions for private explorers. Soon it will be the turn of the next spaceflight participant Anousheh Ansari to contribute to ESA’s scientific programme.

Effect of space radiation on the human body: Chromosome-2 Experiment
During space flights, crew members are constantly exposed to different types of radiation. Such radiation damages the cellular DNA, and may induce mutations, which could be associated with an enhanced risk of developing cancer. Induced mutations can be analyzed in lymphocytes (white blood cells): the Chromosome-2 Experiment studies chromosome change and sensitivity to radiation in lymphocytes of ISS crew members, with the objective to assess the genetic impact of radiation on the crew.

The quality of the radiation field cannot be simulated on Earth and it is therefore necessary to conduct the analyses in the space environment. The results of the study will enable a better assessment of the genetic risk for humans in space and, in the long-term, will contribute to optimise radiation shielding for future space exploration missions.

Ansari will act as a test subject providing blood samples before and after her flight.

Looking for bacteria onboard the ISS: SAMPLE Experiment
The danger of contamination by pathogenic organisms is a serious problem on space missions. In weightlessness, some bacteria grow faster than under conditions on Earth, and they are much more antibiotic resistant. However, it is not known whether and to which extent this different behaviour of bacteria could affect the health of the crew or damage technical equipment on board.

The SAMPLE experiment’s aim is to investigate what kind of microbial species are to be found on board the International Space Station and how these adapt to space environment conditions. Ansari will take samples from herself and from certain areas of the Station, by rubbing swab sticks over surfaces susceptible to having bacteria, for example switches, keyboards and personal hygiene equipment.

Where does back pain come from? Low Back Pain Experiment
In the weightless conditions of space, astronauts often experience some form of lower back pain. This is extraordinary since, on Earth, back pain is associated with heavy spinal load, mainly as a consequence of gravity.

Scientists have therefore developed a hypothesis that lower back pain may develop without compression of the vertebrae. The explanation of the problem comes from the fact that the lower part of the vertebrae, the sacral bone, has to be kept in position between the two hipbones. And a deep ‘muscle corset’ plays an important role in this process, with the tonic postural muscles being activated when getting up in the morning and deactivated when resting.

It is hypothesised that this protective mechanism does not work in space. In space astronauts’ bones lose calcium and strength, their muscles lose mass: therefore, it is thought that the deep muscle corset atrophies during spaceflight, leading to strain in certain ligaments, in particular in the lower region in the back, and causing as a consequence low back pain in astronauts.

The Low Back Pain experiment aims at studying the development of low back pain on crews during spaceflight, with the objective to assess the level of atrophy in the deep muscle corset in response to exposure to microgravity.

Ansari will complete a daily questionnaire during her flight reporting on back complaints. The results will be compared with similar pre-flight and post-flight ground measurements, in order to obtain a better understanding of the correlation between muscle use/disuse and back pain, which would be useful for developing countermeasures for this problem not only in space but also on Earth.

What are the causes of anaemia? NEOCYTOLYSIS experiment
The NEOCYTOLYSIS experiment aims at studying the effects of weightlessness on the hemopoietic system, the system of the body responsible for the formation of blood cells.

The experiment will study a process called neocytolysis, i.e. the selective destruction of young red blood cells. This process has been observed in astronauts as an adaptive response of the body to the specific condition of weightlessness. In space, in absence of gravity, the blood which is normally held in the extremities by gravity shifts centrally, causing high red cells density in blood vessels in the upper part of the body; this induces a response, which aims at resetting the mass of red blood cells by means of their selective destruction, and that causes in turn a temporary anaemia in astronauts over the first days after landing.

This process is therefore regarded for astronauts as a natural response to specific environmental conditions. However, it may also occur in pathological conditions, for example as anaemia in patients affected by renal failure. The experiment will be therefore of crucial importance for casting light and possibly for contributing to the development of solutions for this serious disease.

Ansari will act as a test subject providing blood samples before and after her flight.

Original Source: ESA News Release

Earth-Sized Planets are Probably Common

September 8th, 2006

Of the many extrasolar planetary systems discovered so far, more than a third could contain Earth-like planets. This is according to a new study by scientists associated with NASA’s Center for Astrobiology. It was originally thought that Jupiter-sized planets should clear out their star systems as they form, but some new calculations show that they actually promote the formation of rocky planets - and even help pull in icy objects that deliver water to the inner planets.

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More than one-third of the giant planet systems recently detected outside our solar system may harbor Earth-like planets covered in deep global oceans that offer abundant potential for life, according to a new study by scientists associated with NASA’s Astrobiology Institute.

The study focuses on planetary systems that contain “Hot Jupiters”: gas giant planets that orbit extremely close to their parent stars — even closer than Mercury to our own sun. Hot Jupiters are believed to have migrated inward toward their parent stars just as the planetary systems were forming, disrupting the space environment and triggering the formation of ocean-covered, Earth-like planets in a “habitable zone” conducive to the evolution of life, according to the new study.

Previous studies have indicated that as Hot Jupiters plowed through proto-planetary material on their inward migrations toward their parent stars, all the surrounding material would be vacuumed up or ejected from the system. “The new models indicate these early ideas were probably wrong,” said co-author Sean Raymond of the University of Colorado, Boulder.

Published in the Sept. 8 issue of Science, the study indicates Hot Jupiters push and pull proto-planetary disk material during their journeys, flinging rocky debris outward where it is likely to coalesce into Earth-like planets. At the same time, turbulent forces from the surrounding dense gas slow the small, icy bodies in the outer reaches of the disk, causing them to spiral inward and deliver water to the fledgling planets. These planets may eventually host oceans several miles deep, according to the study.

The research team ran exhaustive simulations lasting more than eight months each on more than a dozen desktop computers, starting from a disk of more than a thousand rocky and icy protoplanets about the size of the moon. The initial conditions for each computer model were based on current theories of how planets formed in our own solar system and simulated about 200 million years of planetary evolution.

The team concluded that approximately one out of three of the known planetary systems could have formed as-yet-undetected Earth-like planets in so-called habitable zones similar to the one in which Earth’s orbit resides. “The fraction of known systems that could have the potential for life may be significantly higher than we had thought,” said co-author Mandel Avi of Pennsylvania State University, University Park and NASA’s Goddard Space Flight Center, Greenbelt, Md.

The new collaborative research effort may allow planet hunters to determine rough limits for where to search for habitable planets in known systems of giant planets. “We hope other researchers may be able to use our new model to narrow the list of potential targets in the search for other Earths”, said co-author Steinn Sigurdsson of Pennsylvania State University.

Original Source: NASA News Release

The Milky Way’s Bulge Formed Early

September 12th, 2006

Although our Milky Way formed from a single, giant cloud of gas and dust, new research has found that the stars in the disc are different from those in the bulge. A new survey has measured the amount of oxygen in 50 stars in the Milky Way using the ESO’s Very Large Telescope to determine when and how the stars formed. The survey found that stars in the bulge probably formed in less than a billion years after the Big Bang, when the Universe was still young; the stars in the disc came later.

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Looking in detail at the composition of stars with ESO’s VLT, astronomers are providing a fresh look at the history of our home galaxy, the Milky Way. They reveal that the central part of our Galaxy formed not only very quickly but also independently of the rest.

“For the first time, we have clearly established a ‘genetic difference’ between stars in the disc and the bulge of our Galaxy,” said Manuela Zoccali, lead author of the paper presenting the results in the journal Astronomy and Astrophysics [1]. “We infer from this that the bulge must have formed more rapidly than the disc, probably in less than a billion years and when the Universe was still very young.”

The Milky Way is a spiral galaxy, having pinwheel-shaped arms of gas, dust, and stars lying in a flattened disc, and extending directly out from a spherical nucleus of stars in the central region. The spherical nucleus is called a bulge, because it bulges out from the disc. While the disc of our Galaxy is made up of stars of all ages, the bulge contains old stars dating from the time the galaxy formed, more than 10 billion years ago. Thus, studying the bulge allows astronomers to know more about how our Galaxy formed.

To do this, an international team of astronomers [2] analysed in detail the chemical composition of 50 giant stars in four different areas of the sky towards the Galactic bulge. They made use of the FLAMES/UVES spectrograph on ESO’s Very Large Telescope to obtain high-resolution spectra.

The chemical composition of stars carries the signature of the enrichment processes undergone by the interstellar matter up to the moment of their formation. It depends on the previous history of star formation and can thus be used to infer whether there is a ‘genetic link’ between different stellar groups. In particular, comparison between the abundance of oxygen and iron in stars is very illustrative. Oxygen is predominantly produced in the explosion of massive, short-lived stars (so-called Type II supernovae), while iron instead originates mostly in Type Ia supernovae [3], which can take much longer to develop. Comparing oxygen with iron abundances therefore gives insight on the star birth rate in the Milky Way’s past.

“The larger size and iron-content coverage of our sample allows us to draw much more robust conclusions than were possible until now,” said Aurelie Lecureur, from the Paris-Meudon Observatory (France) and co-author of the paper.

The astronomers clearly established that, for a given iron content, stars in the bulge possess more oxygen than their disc counterparts. This highlights a systematic, hereditary difference between bulge and disc stars.

“In other words, bulge stars did not originate in the disc and then migrate inward to build up the bulge but rather formed independently of the disc,” said Zoccali. “Moreover, the chemical enrichment of the bulge, and hence its formation timescale, has been faster than that of the disc.”

Comparisons with theoretical models indicate that the Galactic bulge must have formed in less than a billion years, most likely through a series of starbursts when the Universe was still very young.

Notes
[1]: “Oxygen abundances in the Galactic bulge: evidence for fast chemical enrichment” by Zoccali et al. It is freely available from the publisher’s web site as a PDF file.

[2]: The team is composed of Manuela Zoccali and Dante Minniti (Universidad Catolica de Chile, Santiago), Aurelie Lecureur, Vanessa Hill and Ana Gomez (Observatoire de Paris-Meudon, France), Beatriz Barbuy (Universidade de Sao Paulo, Brazil), Alvio Renzini (INAF-Osservatorio Astronomico di Padova, Italy), and Yazan Momany and Sergio Ortolani (Universita di Padova, Italy).

[3]: Type Ia supernovae are a sub-class of supernovae that were historically classified as not showing the signature of hydrogen in their spectra. They are currently interpreted as the disruption of small, compact stars, called white dwarfs, that acquire matter from a companion star. A white dwarf represents the penultimate stage of a solar-type star. The nuclear reactor in its core has run out of fuel a long time ago and is now inactive. However, at some point the mounting weight of the accumulating material will have increased the pressure inside the white dwarf so much that the nuclear ashes in there will ignite and start burning into even heavier elements. This process very quickly becomes uncontrolled and the entire star is blown to pieces in a dramatic event. An extremely hot fireball is seen that often outshines the host galaxy.

Original Source: ESO News Release

Connection Found Between the Earth and Space Weather

September 12th, 2006

Researchers have found a connection between weather here on Earth, and the weather in space. The connection comes from the ionosphere, a high-altitude region of the Earth’s atmosphere formed by solar X-rays and ultraviolet light. NASA satellites found that regions of the ionosphere become more dense above areas of thunderstorm activity in the lower atmosphere. This is a surprising discovery because the ionosphere and the lower atmosphere are separated by hundreds of kilometres.

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Weather on Earth has a surprising connection to space weather occurring high in the electrically-charged upper atmosphere, known as the ionosphere, according to new results from NASA satellites.

“This discovery will help improve forecasts of turbulence in the ionosphere, which can disrupt radio transmissions and the reception of signals from the Global Positioning System,” said Thomas Immel of the University of California, Berkeley, lead author of a paper on the research published August 11 in Geophysical Research Letters.

Researchers discovered that tides of air generated by intense thunderstorm activity over South America, Africa and Southeast Asia were altering the structure of the ionosphere.

The ionosphere is formed by solar X-rays and ultraviolet light, which break apart atoms and molecules in the upper atmosphere, creating a layer of electrically-charged gas known as plasma. The densest part of the ionosphere forms two bands of plasma close to the equator at a height of almost 250 miles. From March 20 to April 20, 2002, sensors on board NASA’s Imager for Magnetopause to Aurora Global Exploration (IMAGE) satellite recorded these bands, which glow in ultraviolet light.

Using pictures from IMAGE, the team discovered four pairs of bright regions where the ionosphere was almost twice as dense as the average. Three of the bright pairs were located over tropical rainforests with lots of thunderstorm activity — the Amazon Basin in South America, the Congo Basin in Africa, and Indonesia. A fourth pair appeared over the Pacific Ocean. Researchers confirmed that the thunderstorms over the three tropical rainforest regions produce tides of air in our atmosphere using a computer simulation developed by the National Center for Atmospheric Research, Boulder, Colo., called the Global Scale Wave Model.

The connection to plasma bands in the ionosphere surprised scientists at first because these tides from the thunderstorms can not affect the ionosphere directly. The gas in the ionosphere is simply too thin. Earth’s gravity keeps most of the atmosphere close to the surface. Thunderstorms develop in the lower atmosphere, or troposphere, which extends almost 10 miles above the equator. The gas in the plasma bands is about 10 billion times less dense than in the troposphere. The tide needs to collide with atoms in the atmosphere above to propagate, but the ionosphere where the plasma bands form is so thin, atoms rarely collide there.

However, the researchers discovered the tides could affect the plasma bands indirectly by modifying a layer of the atmosphere below the bands that shapes them. Below the plasma bands, a layer of the ionosphere called the E-layer becomes partially electrified during the day. This region creates the plasma bands above it when high-altitude winds blow plasma in the E-layer across the Earth’s magnetic field. Since plasma is electrically charged, its motion across the Earth’s magnetic field acts like a generator, creating an electric field. This electric field shapes the plasma above into the two bands. Anything that would change the motion of the E-layer plasma would also change the electric fields they generate, which would then reshape the plasma bands above.

The Global Scale Wave Model indicated the tides should dump their energy about 62 to 75 miles above the Earth in the E-layer. This disrupts the plasma currents there, which alters the electric fields and creates dense, bright zones in the plasma bands above.

“The single pair of bright zones over the Pacific Ocean that is not associated with strong thunderstorm activity shows the disruption is propagating around the Earth, making this the first global effect on space weather from surface weather that’s been identified,” said Immel. “We now know that accurate predictions of ionospheric disturbances have to incorporate this effect from tropical weather.”

“This discovery has immediate implications for space weather, identifying four sectors on the Earth where space storms may produce greater ionospheric disturbances. North America is in one of these sectors, which may help explain why the U.S. suffers uniquely extreme ionospheric conditions during space weather events,” Immel said.

Measurements made by NASA’s Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite from March 20 to April 20, 2002, have confirmed that the dense zones exist in the plasma bands. Researchers now want to understand whether the effect changes with seasons or large events, like hurricanes.

The research was funded by NASA. The National Center for Atmospheric Research is sponsored by the National Science Foundation, Arlington, Va.

The team includes Immel, Scott England, Stephen Mende, and Harald Frey of the University of California, Berkeley; Eiichi Sagawa of the National Institute of Information and Communications Technology, Tokyo, Japan; Sid Henderson and Charles Swenson of Utah State University, Logan, Utah; Maura Hagan of the National Center for Atmospheric Research High Altitude Observatory, Boulder, Colo.; and Larry Paxton of the Johns Hopkins University Applied Physics Laboratory, Laurel, Md.

Original Source: NASA News Release