"Las nubes marcianas que estamos estudiando están compuestas de hielo de agua, como algunas nubes en la Tierra. No obstante, se forman a muy bajas temperaturas, a veces por debajo de los 100°C bajo cero (148 grados Fahrenheit bajo cero), afirmaba Tony Colaprete, un científico del centro de investigación Ames de la NASA. "Lo que hemos encontrado en nuestro laboratorio es que es mucho más difícil de iniciar la formación de nubes a estas temperaturas de lo que habíamos pensado". "Esta dificultad genera grandes partículas de nubes, que cae en a la atmósfera más rápidamente y, por tanto, resulta una menor masa nubosa y una atmósfera más seca".
Anteriormente los científicos creían que las nubes marcianas se habían formado a un 100% de humedad relativa, pero este nuevo estudio muestra que el aire marciano debería estar más sobresaturado con agua para formar nubes de lo que los científicos habían estimado antes.
"Queremos entender el clima de Marte y como funciona el ciclo del agua marciano" comentaba Colaprete. "Las nubes son parte integral de éste sistema, como en la Tierra. De todas formas, asumir que las nubes se forman y comportan de igual manera que en la Tierra puede ser una suposición equivocada".
Un mayor entendimiento de los procesos que controlan las nubes marcianas y el ciclo del agua son críticos para entender el clima pasado y actual de Marte. Un gran casquete polar de agua en el polo norte marciano domina el ciclo marciano del agua. Durante el verano del hemisferio norte, este casquete polar sufre evaporación, y los vientos transportan el vapor de agua resultante al polo sur.
"La cantidad de agua en la atmósfera marciana varía enormemente en el espacio y en el tiempo" afirma Colaprete. Las nubes en la atmósfera controlan enormemente la cantidad de agua que se mueve entre un polo y otro. "El agua que alcanza el polo sur en invierno se congela la superficie". "En la primavera del hemisferio sur, este agua se vuelve a evapora y vuelve al casquete polar norte. El ciclo se repite año tras año marciana.
Si toda el agua de la atmósfera se volviera a congelar será superficie, crearía una capa de hielo de aproximadamente un quinto del espesor de un cabello humano. "La masa de nubes representa sólo el 10 por 20% del contenido total de agua. En todas formas, la liviana atmósfera marciana es mucho más sensible y reactiva a la influencia de estas nubes" finalizaba Colaprete.• Noticia Original: NASA
Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com
quinta-feira, 31 de janeiro de 2008
Menos agua en las nubes de Marte
Físicos brasileiros conseguem "despir" buraco negro
Publicidade
RAFAEL GARCIA
da Folha de S.Paulo
Uma dupla de físicos brasileiros conseguiu demonstrar como é possível "despir" um buraco negro para revelar o que há dentro desse estranho tipo de objeto cósmico.RAFAEL GARCIA
da Folha de S.Paulo
Usando conceitos de física quântica, George Matsas e André da Silva, do Instituto de Física Teórica da Unesp, elaboraram um modelo matemático que elimina a "fronteira" do buraco negro, o limite de aproximação a partir do qual não se pode escapar de sua atração.
O objeto, descrito em estudo na revista "Physical Review Letters", porém, é de uma classe especial.
Um buraco negro convencional pode se formar a partir do colapso de uma estrela, quando ocorre uma concentração colossal de matéria no espaço de um só ponto, chamado "singularidade".
Sua força gravitacional é tão grande que nada, nem mesmo a luz, consegue escapar da fronteira batizada de "horizonte de eventos" pelos físicos.
O que Matsas e Silva descrevem, contudo, é o que os físicos chamam de 'singularidade nua', um buraco negro sem horizonte. Em tese, energia e matéria podem escapar dos seus arredores e, portanto, a singularidade seria observável.
Para chegar ao resultado, porém, os físicos tiveram de resolver um problema imposto pela teoria da relatividade geral, de Einstein, que explica a gravidade.
Física fora da lei
"Nós chamamos de singularidade aquilo no qual as equações da natureza quebram, o que é uma situação muito ruim, porque nós físicos acreditamos que tudo pode ser matematizado", diz Matsas. "Mas quão ruim é ter uma singularidade na relatividade geral? Se ela estiver dentro de um horizonte de eventos, em princípio, tudo bem, porque mesmo que não se saiba descrevê-la, isso não influencia o resto do Universo, já que nada pode escapar de dentro [da fronteira do buraco]."
Há problemas, porém, em recorrer à relatividade para analisar o problema. Uma vez que a singularidade é um ponto infinitamente pequeno, há fenômenos nos buracos negros que só podem ser elucidados pelas equações da mecânica quântica, teoria que explica o mundo das partículas elementares.
Acontece que a relatividade e a mecânica quântica são teorias incompatíveis entre si. E a maneira com que os físicos concebem uma singularidade nua é essencialmente relativística.
Um buraco negro pode perder seu horizonte de eventos ao entrar em rotação com velocidade grande o suficiente para "expulsá-lo" por meio de força centrífuga --a mesma força que atira crianças para fora de um carrossel. Mas as equações de Einstein impedem que um objeto entre em um buraco negro com velocidade grande o suficiente para aumentar sua rotação e expor a singularidade.
Barreira energética
Na prática, o que acontece, é que uma partícula teria de romper uma espécie de "barreira energética" intransponível antes de contribuir para que a rotação do buraco negro ultrapasse o limite que o transformaria em singularidade nua.
Analisando o problema do ponto de vista quântico, porém, Matsas e Silva conseguiram fazer --em teoria, diga-se logo-- com que partículas entrassem no buraco negro por meio de um efeito chamado "tunelamento". É um fenômeno conhecido na física quântica, no qual uma partícula pode atravessar essa barreira energética tomando uma espécie de atalho, desaparecendo de um lado e aparecendo do outro.
Não é nenhuma mágica, diz Matsas: "O tunelamento é muito comum em situações microscópicas, só fica mais improvável nas macroscópicas".
Com o trabalho, os brasileiros procuram contribuir para superar o maior desafio atual da física: unificar a mecânica quântica e a relatividade geral em uma teoria só. Pode a descoberta ajudar nessa meta? "Pode ser que sim, mas não é garantido", diz Matsas.
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Céu claro para todos!
José Geraldo Mattos - Moderador
"A desarmonia do universo é a mais perfeita criação; não foi e jamais será imitada pelo gênio humano" - (Prof. A. Seixas Neto) 
Morning Sky Alert
Space Weather News for Jan. 31, 2008
http://spaceweather.com
http://spaceweather.com
MORNING SKY ALERT: Set your alarm for dawn. On Friday morning, February 1st,
Venus and Jupiter converge in the southeastern sky less than 1 degree apart;
they will beam through the rosy glow of dawn like a pair of celestial
headlights. It's a spectacular view worth waking up early to see. The
February 1st alignment kicks off four mornings of beautiful views as the
crescent Moon moves in to join Venus and Jupiter over the weekend. Visit
http://spaceweather.com for sky maps and photos.
Visite: http://astronomicando.blogspot.com/
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Lucimary Vargas de Oliveira Guardamino Espinoza
Além Paraíba-MG-Brasil
Presidente:
Observatório Astronômico Monoceros
Estacão Meteorológica Nº083/5ºDISME-INMET
CEPESLE -Centro de Estudos e Pesquisas Sertões do Leste
AHAP-Arquivo Histórico de Além Paraíba
http://www.monoceros.xpg.com.br
http://astronomicando.blogspot.com/
http://arqueoastronomy.blogspot.com/
http://www.arquivohistorico-mg.com.br
http://br.groups.yahoo.com/group/Observatorio_Monoceros/
MSN: observatoriomonoceros@hotmail.com
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Mars' Natural Sculptures Pose Mystery
Wind-sculpted Martian landscapes raise questions for scientists about the Red Planet's atmosphere and terrain.
Sand dunes are among the "bedforms" or wind-deposited landforms that appear in new images from NASA's Mars Reconnaissance Orbiter (MRO).
However, scientists remain unsure as to whether winds on present-day Mars are strong enough to create such geological features.
"We're seeing what look like smaller sand bedforms on the tops of larger dunes, and, when we zoom in more, a third set of bedforms topping those," said Nathan Bridges, NASA's Jet Propulsion Laboratory in Pasadena, Calif. "On Earth, small bedforms can form and change on time scales as short as a day."
Other bedforms on Mars take the shape of smaller and more linear ripples, in which sand is mixed with coarser particles.
New details emerged about sediments deposited by winds on the downwind side of rocks.
Such "windtails" show which way the most current winds have blown, Bridges said.
Only rovers and landers have seen such features before, as opposed to an orbiter.
With the University of Arizona's High Resolution Imaging Science Experiment camera (HiRISE), MRO sees features as small as 20 inches from 155 to 196 miles above the Martian surface.
Researchers can now use HiRISE images to infer wind directions over the entire planet.
Scientists also previously discovered miles-long, wind-scoured ridges called "yardangs" with the first Mars orbiter, Mariner 9, in the early 1970s. New HiRISE images reveal surface texture and fine-scale features that are giving insight into how yardangs form.
"HiRISE is showing us just how interesting layers in yardangs are," Bridges said. "For example, we see one layer that appears to have rocks in it. You can actually see rocks in the layer, and if you look downslope, you can see rocks that we think have eroded out from that rocky layer above."
New images show that some layers in the yardangs are made of softer materials that have been modified by wind, he added. The soft material could be volcanic ash deposits, or the dried-up remnants of what once were mixtures of ice and dust, or something else.
"The fact that we see layers that appear to be rocky and layers that are obviously soft says that the process that formed yardangs is no simple process but a complicated sequence of processes," Bridges added.
Some researchers have begun comparing HiRISE images with those taken by NASA's Mars Exploration Rover, in order to identify previously mysterious features such as dark streaks surrounding Victoria Crater. Others continue to find surprises while reexamining features once considered common and uninteresting.
"HiRISE keeps showing interesting things about terrains that I expected to be uninteresting," said Alfred McEwen of the University of Arizona Lunar and Planetary Laboratory, HiRISE principal investigator.
"I was surprised by the diversity of morphology of the thick dust mantles. Instead of a uniform blanket of smooth dust, there are often intricate patterns due to the action of the wind and perhaps light cementation from atmospheric volatiles."
Fonte: Original desta notícia pode ser acessada através do site: http://www.gea.org.br/mss.html
Céu claro para todos!
José Geraldo Mattos - Moderador
"A desarmonia do universo é a mais perfeita criação; não foi e jamais será imitada pelo gênio humano" - (Prof. A. Seixas Neto)
¿Cuál es el lugar más frío del universo?
31-Jan-2008
¿Cuál es el lugar más frío del universo?
No es Miami Beach, si eso es lo que estabas pensando, y tampoco es el polo norte. El lugar más frío conocido se encuentra en el interior de la Nebulosa Boomerang, ubicada en la constelación de Centauro, a 5.000 años luz de distancia de la Tierra.
Esta nebulosa planetaria se forma alrededor de una brillante estrella central, a partir del gas expelido por esta durante las últimas etapas de su vida.
Enlace: http://www.livescience.com/mysteries/080128-coldest-place.html
Posted by:
-------------------------------------------------------------------------
Lucimary Vargas de Oliveira Guardamino Espinoza
Além Paraíba-MG-Brasil
Presidente:
Observatório Astronômico Monoceros
Estacão Meteorológica Nº083/5ºDISME-INMET
CEPESLE -Centro de Estudos e Pesquisas Sertões do Leste
AHAP-Arquivo Histórico de Além Paraíba
http://www.monoceros.xpg.com.br/
http://astronomicando.blogspot.com/
http://arqueoastronomy.blogspot.com/
http://www.arquivohistorico-mg.com.br/
http://br.groups.yahoo.com/group/Observatorio_Monoceros/
MSN: observatoriomonoceros@hotmail.com
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¿Cuál es el lugar más frío del universo?
No es Miami Beach, si eso es lo que estabas pensando, y tampoco es el polo norte. El lugar más frío conocido se encuentra en el interior de la Nebulosa Boomerang, ubicada en la constelación de Centauro, a 5.000 años luz de distancia de la Tierra.
Esta nebulosa planetaria se forma alrededor de una brillante estrella central, a partir del gas expelido por esta durante las últimas etapas de su vida.
En 1995, empleando el telescopio de 15 metros ESO Submilímetro desde Chile, los astrónomos Sahai y Nyman revelaron que hasta el momento, este era el lugar más frío del universo. Con una temperatura de -272ºC, se encuentra apenas un grado por encima del cero absoluto (el límite inferior para cualquier temperatura). Incluso el leve fulgor de la radiación de fondo dejada por el Big Bang, cuya temperatura es de -270ºC, es más cálida que esta nebulosa. Hasta la fecha es el único objeto celeste hallado cuya temperatura es inferior al de la radiación cósmica de fondo.
La característica forma en lazo de la nebulosa Boomerang parece haber sido creada por un viento furioso, a 500.000 km/h, que expulsaba el gas ultrafrío lejos de la moribunda estrella central. Durante los últimos 1.500 años, la estrella ha venido perdiendo hasta una milésima de su masa solar al año, dicen los astrónomos. Esto es un ritmo entre 10 y 100 veces más elevado que el observado en otros cuerpos celestes similares. La rápida expansión de la nebulosa ha posibilitado que se convierta en la región más fría del universo conocido.
Editado por el equipo de Astroseti.
Colaboradores:
- Miguel Artime
- Vicente Díaz
La característica forma en lazo de la nebulosa Boomerang parece haber sido creada por un viento furioso, a 500.000 km/h, que expulsaba el gas ultrafrío lejos de la moribunda estrella central. Durante los últimos 1.500 años, la estrella ha venido perdiendo hasta una milésima de su masa solar al año, dicen los astrónomos. Esto es un ritmo entre 10 y 100 veces más elevado que el observado en otros cuerpos celestes similares. La rápida expansión de la nebulosa ha posibilitado que se convierta en la región más fría del universo conocido.
Editado por el equipo de Astroseti.
Colaboradores:
- Miguel Artime
- Vicente Díaz
Enlace: http://www.livescience.com/mysteries/080128-coldest-place.html
Posted by:
-------------------------------------------------------------------------
Lucimary Vargas de Oliveira Guardamino Espinoza
Além Paraíba-MG-Brasil
Presidente:
Observatório Astronômico Monoceros
Estacão Meteorológica Nº083/5ºDISME-INMET
CEPESLE -Centro de Estudos e Pesquisas Sertões do Leste
AHAP-Arquivo Histórico de Além Paraíba
http://www.monoceros.xpg.com.br/
http://astronomicando.blogspot.com/
http://arqueoastronomy.blogspot.com/
http://www.arquivohistorico-mg.com.br/
http://br.groups.yahoo.com/group/Observatorio_Monoceros/
MSN: observatoriomonoceros@hotmail.com
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Killer Space Rock Theory Is Soaking Wet
 | By SPACE.com Staff posted: 24 January 2008 04:48 am ET |
Dinosaur doomsday was wetter than scientists have thought, according to new images of the crater where the space rock that likely killed the jumbo reptiles landed.
Sixty-five million years ago the asteroid struck the coast of the Yucatan Peninsula, and most scientists think this event played a large role in causing the extinction of 70 percent of life on Earth, including non-avian dinosaurs.
Geophysicists now have created the most detailed 3-D seismic images yet of the mostly submerged Chicxulub impact crater. The data reveal that the asteroid landed in deeper water than previously assumed and therefore released about 6.5 times more water vapor into the atmosphere.
The images also show the crater contained sulfur-rich sediments that would have reacted with the water vapor to create sulfate aerosols. These compounds in the atmosphere would have made the impact deadlier by cooling the climate and producing acid rain.
"The greater amount of water vapor and consequent potential increase in sulfate aerosols needs to be taken into account for models of extinction mechanisms," said Sean Gulick, a geophysicist at the University of Texas at Austin who led the study.
The findings will be published in the February 2008 issue of the journal Nature Geosciences.
The asteroid impact alone was probably not responsible for the mass extinction, Gulick said. More likely, a combination of environmental changes over different time scales took their toll.
Many large land animals, including the dinosaurs, might have baked to death within hours or days of the impact as ejected material fell from the sky, heating the atmosphere and setting off firestorms. More gradual changes in climate and acidity might have had a larger impact in the oceans.
If there was more acid rain than scientists had previously calculated, that could help explain why many smaller marine creatures were affected, because the rain could have turned the oceans more acidic.
There is some evidence that marine organisms more resistant to a range of pH survived, while more sensitive creatures did not.
Fonte: Original desta notícia pode ser acessada através do site: http://www.gea.org.br/mss.html
Céu claro para todos!
José Geraldo Mattos - Moderador
"A desarmonia do universo é a mais perfeita criação; não foi e jamais será imitada pelo gênio humano" - (Prof. A. Seixas Neto)
Unusual supernovae may reveal black holes
UC-SANTA CRUZ NEWS RELEASE
Posted: January 29, 2008
A strange and violent fate awaits a white dwarf star that wanders too close to a moderately massive black hole. According to a new study, the black hole's gravitational pull on the white dwarf would cause tidal forces sufficient to disrupt the stellar remnant and reignite nuclear burning in it, giving rise to a supernova explosion with an unusual appearance. Observations of such supernovae could confirm the existence of intermediate-mass black holes, currently the subject of much debate among astronomers.
"Our supercomputer simulations show a peculiar supernova that would be a unique signature of an intermediate-mass black hole," said Enrico Ramirez-Ruiz, assistant professor of astronomy and astrophysics at the University of California, Santa Cruz.
Posted: January 29, 2008
A strange and violent fate awaits a white dwarf star that wanders too close to a moderately massive black hole. According to a new study, the black hole's gravitational pull on the white dwarf would cause tidal forces sufficient to disrupt the stellar remnant and reignite nuclear burning in it, giving rise to a supernova explosion with an unusual appearance. Observations of such supernovae could confirm the existence of intermediate-mass black holes, currently the subject of much debate among astronomers.
 This series of images shows the interaction of a white dwarf star with a black hole. As it passes the black hole, the white dwarf becomes strongly compressed and heated (top left), triggering an explosion. Most of the stellar mass is ejected into space (the "bubble" in the upper right part of the debris in the top right image), while the rest (the cusp-like part of the image) falls toward the black hole. While the ejected matter expands rapidly, the infalling matter builds a violent, thick accretion disk around the black hole. |
Ramirez-Ruiz and his collaborators--Stephan Rosswog of Jacobs University in Bremen, Germany, and William Hix of Oak Ridge National Laboratory--used detailed computer simulations to follow the entire process of tidal disruption of a white dwarf by a black hole. Their simulations included gas dynamics, gravity, and nuclear physics, requiring weeks of computer time to simulate events that would take place in a fraction of a second. A paper describing their results has been accepted for publication in Astrophysical Journal Letters, and a preprint is currently available online.
"Every star that is not too massive ends up as a white dwarf, so they are very common. We were interested in whether tidal disruption can bring this stellar corpse to life again," said Rosswog, the first author of the paper.
A white dwarf can explode as a "type Ia" supernova if it accumulates enough mass by siphoning matter away from a companion star. When it reaches a critical mass (about 1.4 times the mass of the Sun), the white dwarf collapses and explodes. Astronomers use these type Ia supernovae as "standard candles" for cosmic distance measurements because their brightness evolves over time in a predictable manner.
The new paper describes a distinctly different mechanism for igniting a white dwarf, in which tidal disruption by a black hole causes drastic compression of the stellar material. The white dwarf is flattened into a pancake shape aligned in the plane of its orbit around the black hole. As each section of the star is squeezed through a point of maximum compression, the extreme pressure causes a sharp increase in temperatures, which triggers explosive burning.
The explosion ejects more than half of the debris from the disrupted star, while the rest of the stellar material falls into the black hole. The infalling material forms a luminous accretion disk that emits x-rays and should be detectable by the Chandra X-ray Observatory, the researchers said.
"This is a new mechanism for ignition of a white dwarf that results in a very different type of supernova than the standard type Ia, and it is followed by an x-ray source," Ramirez-Ruiz said.
He estimated that this type of event would occur about 100 times less frequently than the standard type Ia supernovae, but should be detectable by future surveys designed to observe large numbers of supernovae. The Large Synoptic Survey Telescope (LSST), planned for completion in 2013, is expected to discover hundreds of thousands of type Ia supernovae per year.
"These exotic creatures will start showing up in the data from the LSST," Ramirez-Ruiz said. "We want to predict the light curves so we can look for them in the survey data."
The mechanism described in the paper requires a black hole that is neither too small nor too big. Such intermediate-mass black holes (500 to 1,000 times the mass of the Sun) may reside in some globular star clusters, but there is much less evidence for their existence than there is for the relatively small stellar black holes (tens of times the mass of the Sun) or for supermassive black holes (a few million times the mass of the Sun), found at the centers of galaxies.
The new paper describes in detail the disruption of a white dwarf with two-tenths the mass of the Sun by a black hole 1,000 times the mass of the Sun. The researchers also found that they can vary the mass of the white dwarf and still get the same outcome--tidal disruption and ignition of the white dwarf.
"We can ignite the whole mass range of white dwarfs if they get close enough to the black hole," Rosswog said.
This research was supported by the Department of Energy's Program for Scientific Discovery through Advanced Computing.
Fonte: Original desta notícia pode ser acessada através do site: http://www.gea.org.br/mss.html
Céu claro para todos!
José Geraldo Mattos - Moderador
"A desarmonia do universo é a mais perfeita criação; não foi e jamais será imitada pelo gênio humano" - (Prof. A. Seixas Neto)
Posted By:
-------------------------------------------------------------------------
Lucimary Vargas de Oliveira Guardamino Espinoza
Além Paraíba-MG-Brasil
Presidente:
Observatório Astronômico Monoceros
Estacão Meteorológica Nº083/5ºDISME-INMET
CEPESLE -Centro de Estudos e Pesquisas Sertões do Leste
AHAP-Arquivo Histórico de Além Paraíba
http://www.monoceros.xpg.com.br
http://astronomicando.blogspot.com/
http://arqueoastronomy.blogspot.com/
http://www.arquivohistorico-mg.com.br
http://br.groups.yahoo.com/group/Observatorio_Monoceros/
MSN: observatoriomonoceros@hotmail.com
--------------------------------------------------------------------------
Lucimary Vargas de Oliveira Guardamino Espinoza
Além Paraíba-MG-Brasil
Presidente:
Observatório Astronômico Monoceros
Estacão Meteorológica Nº083/5ºDISME-INMET
CEPESLE -Centro de Estudos e Pesquisas Sertões do Leste
AHAP-Arquivo Histórico de Além Paraíba
http://www.monoceros.xpg.com.br
http://astronomicando.blogspot.com/
http://arqueoastronomy.blogspot.com/
http://www.arquivohistorico-mg.com.br
http://br.groups.yahoo.com/group/Observatorio_Monoceros/
MSN: observatoriomonoceros@hotmail.com
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Mercury surprises from MESSENGER
MESSENGER's recent flyby of Mercury has provided scientists with an entirely new, and surprising, view of the innermost planet.
Provided by NASA
 This frame, taken by MESSENGER's Narrow Angle Camera, shows a region of Mercury's surface previously unseen by spacecraft and a large scarp crossing vertically through the scene, on the far right of the image. This scarp is the northern continuation of the one seen in the NAC image released on January 16. The width of this image is about about 125 miles (200 kilometers), showing that these scarps can be hundreds of kilometers long on Mercury. NASA/JHUAPL/CIW [View Larger Image] The recent flyby of Mercury by NASA's MESSENGER spacecraft has given scientists an entirely new look at a planet once thought to have characteristics similar to those of Earth's moon. Researchers are amazed by the wealth of images and data that show a unique world with a diversity of geological processes and a very different magnetosphere from the one discovered and sampled more than 30 years ago. After a journey of more than 2 billion miles and three and a half years, NASA's MErcury Surface, Space ENvironment, GEochemistry and Ranging spacecraft made its first flyby on Jan. 14. The mission is the first sent to orbit the planet closest to our sun. The spacecraft's cameras and other sophisticated, high-technology instruments collected more than 1,200 images and made other science observations. Data included the first up-close measurements of Mercury since the Mariner 10 spacecraft's third and final flyby on March 16, 1975. "This flyby allowed us to see a part of the planet never before viewed by spacecraft, and our little craft has returned a gold mine of exciting data," said Sean Solomon, MESSENGER's principal investigator, Carnegie Institution of Washington. "From the perspectives of spacecraft performance and maneuver accuracy, this encounter was near-perfect, and we are delighted that all of the science data are now on the ground." Unlike the moon, the spacecraft showed that Mercury has huge cliffs with structures snaking up hundreds of miles across the planet's face. These cliffs preserve a record of patterns of fault activity from early in the planet's history. The spacecraft also revealed impact craters that appear very different from lunar craters. Instruments provided a topographic profile of craters and other geological features on the night side of Mercury. The spacecraft also discovered a unique feature that scientists dubbed "The Spider." This formation never has been seen on Mercury before and nothing like it has been observed on the moon. It lies in the middle of a large impact crater called the Caloris basin and consists of more than 100 narrow, flat-floored troughs radiating from a complex central region. "The Spider has a crater near its center, but whether that crater is related to the original formation or came later is not clear at this time," said James Head, science team co-investigator at Brown University. Now that the spacecraft has shown scientists the full extent of the Caloris basin, its diameter has been revised upward from the Mariner 10 estimate of 800 miles to perhaps as large as 960 miles from rim to rim. The plains inside the Caloris basin are distinctive and more reflective than the exterior plains. Impact basins on the moon have opposite characteristics. The magnetosphere and magnetic field of Mercury during the flyby appeared to be different from the Mariner 10 observations. The spacecraft found the planet's magnetic field was generally quiet but showed several signatures indicating significant pressure within the magnetosphere. Magnetic fields like Earth's and their resulting magnetospheres are generated by electrical dynamos in the form of a liquid metallic outer core deep in the planet's center. Of the four terrestrial planets, only Mercury and Earth exhibit such a phenomenon. The magnetic field deflects the solar wind from the sun, producing a protective bubble around Earth that shields the surface of our planet from those energetic particles and other sources farther out in the galaxy. Similar variations are expected for Mercury's magnetic field, but the precise nature of its field and the time scales for internal changes are unknown. The next two flybys and the yearlong orbital phase will shed more light on these processes. The spacecraft's suite of instruments has provided insight into the mineral makeup of the surface terrain and detected ultraviolet emissions from sodium, calcium and hydrogen in Mercury's exosphere. It also has explored the sodium-rich exospheric "tail," which extends more than 25,000 miles from the planet. "We should keep this treasure trove of data in perspective," said project scientist Ralph McNutt of the Applied Physics Laboratory, Laurel, Maryland. "With two flybys to come and an intensive orbital mission to follow, we are just getting started to go where no one has been before." |
Fonte: Original desta notícia pode ser acessada através do site: http://www.gea.org.br/mss.html
Céu claro para todos!
José Geraldo Mattos - Moderador
"A desarmonia do universo é a mais perfeita criação; não foi e jamais será imitada pelo gênio humano" - (Prof. A. Seixas Neto)
Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com
Jupiter's giant storms caught in Hubble telescope images
UNIVERSITY OF ARIZONA NEWS RELEASE
Posted: January 24, 2008
A University of Arizona scientist, observing Jupiter with the Hubble Space Telescope last May, took some of the best images of two unusual giant storms that erupted from the planet last spring.
When the Pluto-bound New Horizons spacecraft flew by Jupiter in February 2007, it sent back images that showed a relatively quiet Jupiter, Karkoschka said. Then, on March 25, other astronomers using the Hubble telescope captured a view that showed the beginnings of an intense disturbance at Jupiter's middle northern latitudes, which is where the planet's strongest winds blow.
Karkoschka has been using the Hubble telescope to study how high small hazes reach into Jupiter's upper atmosphere. He makes these observations as the planet's largest moon, Ganymede, dips from view behind the planet. Hubble observations are scheduled months in advance, and the storms didn't appear on the side of the planet Karkoschka was monitoring on April 9.
Posted: January 24, 2008
A University of Arizona scientist, observing Jupiter with the Hubble Space Telescope last May, took some of the best images of two unusual giant storms that erupted from the planet last spring.
Erich Karkoschka of the UA's Lunar and Planetary Laboratory is co-author on a scientific paper being published about his observations in the Jan. 24 issue of the journal Nature.
 See larger image here |
Such giant storms are rare. The last ones occurred in 1990 and 1975, before Hubble and other high-resolution telescopes were in operation. Scientists are interested in such eruptive storms because they are clues to what's going on deeper inside giant gas planets to fuel the jet winds that dominate atmospheres such as those belonging to Jupiter and Saturn.
Augustin Sanchez-Lavega from Spain's Universidad del Pais Vasco coordinated professional and amateur astronomers who monitored the storms as they developed in the following days.
Amateur astronomers play a major role in these kinds of observations, Karkoschka said. "Since professional telescopes are relatively rigid in their schedules, it was great to have amateurs making observations."
 The background image is from Hubble Space Telescope and shows the turbulent pattern generated by the two plumes. The two bright plumes detach in the superimposed small infrared image obtained at the NASA-IRTF facility a month before. Credit: NASA, ESA, IRTF, A. Sanchez-Lavega and R. Hueso (Universidad del Pais Vasco, Spain) See larger image here |
But the storms, initially seen at 250 miles across, grew to about five times that size in less than a day. They rapidly formed two 19-mile-high plumes of ammonia ice and water spewing from Jupiter's deep water clouds.
On May 1, Karkoschka used filters ranging from ultraviolet to visible to infrared on the Hubble telescope to make some of the best images that characterize the structure of the disturbance. Astronomers won more time on the Hubble to view the storms again in early June, but by that time, the disturbance was gone, leaving behind a band of a different color, he noted.
Karkoschka has been studying the atmospheres of outer planets for more than 20 years, first as a graduate student and since as a researcher with the Lunar and Planetary Laboratory. He has used the Hubble Space Telescope to take images of Saturn and its moon Titan, as well as Uranus and Neptune, to study the vertical profile of their gases and aerosols.
Fonte: Original desta notícia pode ser acessada através do site: http://www.gea.org.br/mss.html
Céu claro para todos!
José Geraldo Mattos - Moderador
"A desarmonia do universo é a mais perfeita criação; não foi e jamais será imitada pelo gênio humano" - (Prof. A. Seixas Neto)
NASA scientists get first images of Earth flyby asteroid
It has been determined that there is no possibility of an impact with Earth.
Provided by the Jet Propulsion Laboratory
 This image shows asteroid 2007 TU24 and was taken by the Catalina Sky Survey, October 12, 2007. Steve Larson and Ed Beshore, Catalina Sky Survey [View Larger Image] Scientists at NASA's Jet Propulsion Laboratory in Pasadena, California, have obtained the first images of asteroid 2007 TU24 using high-resolution radar data. The data indicate the asteroid is somewhat asymmetrical in shape, with a diameter roughly 800 feet (250 meters) in size. Asteroid 2007 TU24 will pass within 1.4 lunar distances, or 334,000 miles (538,000 kilometers), of Earth on January 29 at 12:33 a.m. Pacific time (3:33 a.m. Eastern time). "With these first radar observations finished, we can guarantee that next week's 1.4-lunar-distance approach is the closest until at least the end of the next century," says Steve Ostro, JPL astronomer and principal investigator for the project. "It is also the asteroid's closest Earth approach for more than 2,000 years." Scientists at NASA's Near-Earth Object Program Office at JPL have determined that there is no possibility of an impact with Earth in the foreseeable future. |
 These low-resolution radar images of asteroid 2007 TU24 were taken over a few hours by the Goldstone Solar System Radar Telescope in California's Mojave Desert. Image resolution is approximately 20-meters per pixel. Next week, the plan is to have a combination of several telescopes provide higher resolution images. NASA/JPL-Caltech [View Larger Image] Ostro and his team plan further radar observations of asteroid 2007 TU24 using the National Science Foundation's Arecibo Observatory in Puerto Rico on January 27-28 and February 1-4. The asteroid will reach an approximate apparent magnitude 10.3 on January 29-30 before quickly becoming fainter as it moves farther from Earth. On that night, the asteroid will be observable in dark and clear skies through amateur telescopes with apertures of at least 3 inches (7.6 centimeters). An object with a magnitude of 10.3 is about 50 times fainter than an object just visible to the naked eye in a clear, dark sky. NASA detects and tracks asteroids and comets passing close to Earth. The Near Earth Object Observation Program, commonly called "Spaceguard," discovers, characterizes and computes trajectories for these objects to determine if any could be potentially hazardous to our planet. |
Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com
A Stardust-Free Comet
NASA's Stardust mission has just reminded us — for the second time — that we don't know as much about comets as we thought we did.
Comets are thought to be nearly unaltered relics from the formation of the solar system, and Stardust's target, 81P/Wild 2 (pronounced vilt) was considered a perfect target. These days Wild 2 can venture fairly near the Sun (just beyond Mars's orbit). But prior to a close brush with Jupiter in 1974, its orbit was much more distant.
So cosmochemists would have bet money (and maybe did) that the dust and gas coming off Wild 2 when Stardust flew through it in 2004 would be primordial building blocks, released from their deep-freeze confinement after 4½ billion years, that would unlock the key to the solar system's formation.
The smart money, it turns out, was wrong. Not long after Stardust returned to Earth in January 2006 with its precious cargo, it became clear that some of those building blocks came from a very hot kiln. Researchers found an array of minerals that formed at temperatures of at least 2,000°F (1,100°C). Not exactly "deep-freeze" conditions!
Now Stardust has stumped the scientists again. In Science for January 25th, a team led by Hope Ishii (Lawrence Livermore National Laboratory) reports that the captured cometary grains are closer matches to "an inner solar-system asteroid than an outer-solar-system comet with primitive unaltered dust."
In other words, silicate minerals that formed near the Sun were somehow transported to the outer system, where they mingled with ices to create Comet Wild 2. There are no mineral clusters untouched since the Sun first blazed to life, no infusions of exotic isotopes from distant supernovas — if it weren't so dynamically implausible, you might think Comet Wild 2 was an escapee from the asteroid belt.
Did all comets form this way? Probably not. High-flying jets have captured a host of interplanetary dust particles drifting into our atmosphere from space. These tiny treasures have the kind of primitive compositions and unique isotopic mixes that scientists had expected to find in the Stardust samples.
So maybe we just need to go sample another comet (Rosetta, a European-built craft, will do so in 2014). Or maybe our theories of solar-system formation need retooling. Whatver the reason, Stardust has lots of cosmochemists scratching their collective heads right now.
Comets are thought to be nearly unaltered relics from the formation of the solar system, and Stardust's target, 81P/Wild 2 (pronounced vilt) was considered a perfect target. These days Wild 2 can venture fairly near the Sun (just beyond Mars's orbit). But prior to a close brush with Jupiter in 1974, its orbit was much more distant.
NASA's Stardust dashed through the dusty coma of Comet Wild 2 on January 2, 2004, and returned the tiny samples it collected to Earth on January 15, 2006.
NASA / JPL
The smart money, it turns out, was wrong. Not long after Stardust returned to Earth in January 2006 with its precious cargo, it became clear that some of those building blocks came from a very hot kiln. Researchers found an array of minerals that formed at temperatures of at least 2,000°F (1,100°C). Not exactly "deep-freeze" conditions!
Now Stardust has stumped the scientists again. In Science for January 25th, a team led by Hope Ishii (Lawrence Livermore National Laboratory) reports that the captured cometary grains are closer matches to "an inner solar-system asteroid than an outer-solar-system comet with primitive unaltered dust."
In other words, silicate minerals that formed near the Sun were somehow transported to the outer system, where they mingled with ices to create Comet Wild 2. There are no mineral clusters untouched since the Sun first blazed to life, no infusions of exotic isotopes from distant supernovas — if it weren't so dynamically implausible, you might think Comet Wild 2 was an escapee from the asteroid belt.
Did all comets form this way? Probably not. High-flying jets have captured a host of interplanetary dust particles drifting into our atmosphere from space. These tiny treasures have the kind of primitive compositions and unique isotopic mixes that scientists had expected to find in the Stardust samples.
So maybe we just need to go sample another comet (Rosetta, a European-built craft, will do so in 2014). Or maybe our theories of solar-system formation need retooling. Whatver the reason, Stardust has lots of cosmochemists scratching their collective heads right now.
Fonte: Original desta notícia pode ser acessada através do site: http://www.gea.org.br/mss.html
Céu claro para todos!
José Geraldo Mattos - Moderador
"A desarmonia do universo é a mais perfeita criação; não foi e jamais será imitada pelo gênio humano" - (Prof. A. Seixas Neto)
Are We Living in a New Geologic Epoch?
Written by Nancy Atkinson
Have humans changed our planet Earth so much in the past 200 years that we are now living in a new geological age? A group of geologists believes this is the case. They have formally proposed designating a new geologic epoch, the Anthropocene, which would encompass the past 200 years or so of geologic history. The action is appropriate, they say, because during the past 2 centuries, human activity has caused most of the major changes in Earth's topography and climate.
Like rings in a tree, each layer in Earth's geologic record reflects the conditions of the time it was deposited and offers a glimpse into Earth's past. In this geologic history that is written in the rocks and soil of our planet, researchers have differentiated the layers into classifications of time called eons, eras, periods, epochs, and ages that reflect characteristic conditions. For example, the Carboniferous period, which lasted from 360 million to 300 million years ago, is known for the vast deposits of coal that formed from jungles and swamps. Even some of the longer stretches have been named based on biology, such as the Paleozoic ("old life") and the Cenozoic ("recent life").
Earth has been has always been subject to the same kinds of physical forces–wind, waves, sunlight–throughout the planet's existence. But the life that has arisen on the planet has had a much more varied impact such as the rise of plants that has shaped the planet in dramatic ways. But in the past 200 years, ever since the human population has reached 1 billion, our influences have affected the composition of Earth's strata, altering the physical and chemical nature of ocean sediments, ice cores and surface deposits. Some of these influences are the use of fossil fuels and the growth of large cities.
British Geologist Jan Zalasiewicz and several colleagues argue that the International Commission on Stratigraphy should officially mark the end of the current epoch. That would be the Holocene ("entirely recent"), which started after the end of the last ice age, about 10,000 years ago. The new epoch would be the Anthropocene.
The argument has merit, says American geologist Richard Alley. "In land, water, air, ice, and ecosystems, the human impact is clear, large, and growing," he says. "A geologist from the far distant future almost surely would draw a new line, and begin using a new name, where and when our impacts show up."
Original News Source: AAAS ScienceNow
Filed under: Earth
Fonte: Original desta notícia pode ser acessada através do site: http://www.gea.org.br/mss.html
Céu claro para todos!
José Geraldo Mattos - Moderador
"A desarmonia do universo é a mais perfeita criação; não foi e jamais será imitada pelo gênio humano" - (Prof. A. Seixas Neto)
BepiColombo
Ha comenzado oficialmente el desarrollo industrial de BepiColombo, la primera misión europea a Mercurio. El contrato principal, concedido por la ESA a Astrium, se firmó hoy durante una ceremonia celebrada en Friedrichshafen, Alemania. (Noticia traída directamente desde ESA-España)
BepiColombo, una misión que llevará a cabo el estudio más exhaustivo de Mercurio hasta la fecha, fue seleccionada por la ESA como una de sus misiones esenciales en octubre del año 2000. Desde entonces se han llevado a cabo varios estudios industriales y de su evaluación surgió la selección de Astrium como proveedor principal en el 2006.
ESA and Astrium sign the BepiColombo contract
El lanzamiento de BepiColombo está previsto para agosto de 2013 y su llegada a Mercurio para 2019, tras un viaje de seis años al interior del Sistema Solar. Es la primera misión dual a Mercurio, ya que estará formada por una nave espacial europea y otra suministrada por Japón. El programa se desarrolla como una misión conjunta dirigida por la ESA con la colaboración de la Agencia de Exploración Aeroespacial de Japón (JAXA).
"Las dos naves espaciales responderán a interrogantes científicas, como las referentes al origen y la evolución de un planeta cerca de su estrella mayor, o las condiciones del interior del planeta y su campo magnético. Además se pondrá a prueba la teoría general de la relatividad de Einstein", según explicó Johannes Benkhoff, Científico del proyecto BepiColombo de la ESA.
BepiColombo's planetary and magnetospheric orbiters at Mercury
Una de las naves, la Mercury Planetary Orbiter (MPO) de la ESA, llevará a bordo 11 instrumentos para el estudio de la composición tanto en la superficie como en el interior del planeta, mediante técnicas de longitudes de onda e investigación que ofrecerán una precisión sin precedentes.
La segunda nave, Mercury Magnetospheric Orbiter (MMO) de la JAXA, llevará cinco instrumentos para estudiar la magnetosfera del planeta, que es la zona espacial que lo rodea y que está dominada por su campo magnético.
En representación de la ESA, Astrium coordinará una red de subcontratistas que se encargará del diseño y la construcción de la nave MPO de la ESA y el módulo de transporte a Mercurio (Mercury Transfer Module) que llevará a la nave compuesta MPO-MMO a su destino.
"Astrium deberá resolver varias dificultades técnicas", añadió Jan van Casteren, Jefe del proyecto BepiColombo de la ESA. "En gran parte tienen que ver con la dificultad de manejar una nave en el difícil entorno de un planeta tan próximo al Sol, donde la radiación es unas diez veces más intensa que en las cercanías de la Tierra".
BepiColombo's propulsion
A esto se suma que para llegar a Mercurio y entrar en su órbita se requiere una gran cantidad de energía capaz de repeler la fuerza de atracción del Sol. Para lograrlo, en las fases de navegación y de entrada en órbita se recurrirá a propulsión electrosolar, complementada por diversas maniobras apoyadas en la gravedad planetaria y en la propulsión convencional (química).
Para obtener los mejores resultados científicos, la nave Mercury Planetary Orbiter situará su instrumental enfrentado al planeta, algo que nunca se ha intentado en Mercurio debido al intenso calor que irradia la superficie. También se dispondrá de la mayor velocidad de datos jamás utilizada en Mercurio, desde donde se enviará a la Tierra un gran volumen de información de alta calidad para obtener el máximo aprovechamiento científico.
- Noticia original: ESA
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Lucimary Vargas de Oliveira Guardamino Espinoza
Além Paraíba-MG-Brasil
Presidente:
Observatório Astronômico Monoceros
Estacão Meteorológica Nº083/5ºDISME-INMET
CEPESLE -Centro de Estudos e Pesquisas Sertões do Leste
AHAP-Arquivo Histórico de Além Paraíba
http://www.monoceros.xpg.com.br
http://astronomicando.blogspot.com/
http://arqueoastronomy.blogspot.com/
http://www.arquivohistorico-mg.com.br
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MSN: observatoriomonoceros@hotmail.com
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Lucimary Vargas de Oliveira Guardamino Espinoza
Além Paraíba-MG-Brasil
Presidente:
Observatório Astronômico Monoceros
Estacão Meteorológica Nº083/5ºDISME-INMET
CEPESLE -Centro de Estudos e Pesquisas Sertões do Leste
AHAP-Arquivo Histórico de Além Paraíba
http://www.monoceros.xpg.com.br
http://astronomicando.blogspot.com/
http://arqueoastronomy.blogspot.com/
http://www.arquivohistorico-mg.com.br
http://br.groups.yahoo.com/group/Observatorio_Monoceros/
MSN: observatoriomonoceros@hotmail.com
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¡Venus y Júpiter convergen!
Noticias Científicas de la NASA del 29 enero, 2008
Los dos planetas más brillantes del sistema solar estarán convergiendo el viernes 1 de febrero por la mañana en lo que será un espectacular encuentro cercano.
TODO EL REPORTAJE en
http://ciencia.nasa.gov/headlines/y2008/29jan_venusjupiter.htm?list1027835
Página principal: http://ciencia.nasa.gov/
Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com
Conjunción Venus e Jupiter un día antes de su máximo acercamiento
Haz clic en las imagenes para amplialas
Fonte: http://www.acodea.org/galeria/v/arquimag/Planetas/
Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
Buracos negros vagam pela galáxia
Astrônomos nos Estados Unidos disseram nesta semana que centenas de buracos negros podem estar vagando pela galáxia, prontos para
devorar planetas e estrelas pelo caminho.
A força gravitacional dos buracos é tão grande que nem mesmo a luz
conseguiria escapar deles, caso de aproxine a uma distância-limite
conhecida como horizonte de eventos.
A teoria dos astrônomos foi publicada durante um encontro científico
no Estado americano do Texas.
Os cientistas acreditam que centenas de buracos negros podem ter
sido formados da colisão de outros buracos negros. As simulações
msotram que, se dois buracos negros de tamanhos diferentes, ou
dotados de rotação, se chocam, as leis da física determinam que o
novo buraco, gerado pela fusão dos anteriores, deverá disparar pelo
espaço.
Simulações feitas em supercomputadores pela Vanderbilt University,
em um trabalho liderado pela astrônoma Kelly Holley-Bockelmann,
indicam que os buracos negros viajariam em uma velocidade de até
quatro mil quilômetros por segundo.
Segundo eles, os buracos negros não ameaçam diretamente a Terra.
Eles têm tamanho intermediário, e seus horizontes de eventos se
estendem a apenas algumas centenas de quilômetros do espaço.
Fonte:http://groups.
Posted by:
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com
.
Como sabemos que o universo está se expandindo?
O site LiveScience.
Astronomia no Planetário Adler e pesquisador da Universidade de
Chicago. Segue o que ele disse:
"Depois de alguns anos de Albert Einstein ter desenvolvido sua
famosa (e hoje em dia bastante testada) teoria da Relatividade
Geral, em 1915 ele a aplicou à todo o universo e descobriu algo
incrível. A teoria prevê que todo o universo ou está expandindo ou
está se contraindo. Não há outra alternativa. Para que o Universo
fique estático seria como um lápis equilibrado apenas em sua
ponta... possível mas muito, muito improvável e difícil de
permanecer desta maneira.
Em 1929 o astrônomo Edwin Hubble mediu as velocidades de uma grande
seleção de galáxias. Ele esperava similaridades entre a quantidade
de galáxias que estivesse se movendo em nossa direção e se afastando
de nós. Afinal, a Terra não é um ponto particularmente especial do
universo.
Ao invés disso ele descobriu que quase todas as galáxias estão se
distanciando de nós.
Desde os tempos de Hubble nós temos observado milhões de galáxias
com melhores equipamentos e verificado seus resultados. Como a
exceção de um punhado de galáxias próximas a nós, todas as demais
está se distanciando de nós.
E, em realidade, quanto mais distante ela está, mais rapidamente ela
se distancia. Isso se encaixa muito bem nas previsões de Einstein.
As galáxias parecem se distanciar de nós por que todo o universo
está aumentando. O espaço entre as galáxias está se esticando! E
quanto mais longe uma galáxia está, mais espaço há para esticar,
portanto a galáxia aparenta estar se distanciando de nós com maior
velocidade.
Nos últimos 50 anos astrônomos tem observado muitos outros fatos
sobre o universo que apontam para o fato dele estar se expandindo.
Enquanto teorias isoladas podem explicar uma ou duas destas
descobertas, a expansão do universo é a única teoria que pode
explicar todas de uma só vez. E a cada ano a pilha de evidências
fica maior!"
Essa também é uma das evidências, dentre muitas outras, da teoria do
Big Bang, pois se todo o universo está se expandindo provavelmente
houve uma grande explosão que iniciou este movimento.
Fonte:http://groups.
Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com
.
Grande passo para explicar mistério da aceleração em expansão do Universo
PARIS, 30 Jan 2008 (AFP) - Um novo método de observação astronômica permitiu preparar o terreno para elucidar o grande mistério sobre por que a expansão do Universo se acelerou, segundo o último número da revista britânica Nature, que sairá publicado nesta quinta-feira.
Uma equipe internacional de astrônomos acredita ter conseguido as ferramentas adequadas para explicar a enigmática descoberta realizada há uma década, segundo a qual, ao contrário do que se acreditava até então, o Universo se expande mais rapidamente agora do que há milhares de milhões de anos.
Duas hipóteses disputam adeptos na comunidade científica para explicar o fenômeno: a presença de uma energia escura mais poderosa que a força da gravidade, cuja tendência é frear a expansão iniciada com o Big Bang, ou melhor, um erro na teoria da gravitação de Albert Einstein.
O método de observação detalhado na Nature permite medir as posições e velocidades de galáxias distantes, segundo o coordenador do estudo, Luigi Guzzo, que liderou uma equipe de 50 cientistas de 24 instituições.
"A partir das velocidades de uma grande quantidade de galáxias, observadas a 7 bilhões de anos no passado, reconstituimos a estrutura em três dimensões de um volume importante do Universo próximo", escreve um co-autor do trabalho, Olivier Le Fevre.
O mapa evidenciou "as distorsões" registradas em diferentes épocas da história do Universo, que por sua vez permitiram aos astrônomos analisar a natureza da energia escura.
O novo método, que analisa volumes cerca de dez vezes "mais conseqüentes" que os estudados até agora, "deve ser capaz de nos dizer se a aceleração cósmica vem da energia escura ou requer uma modificação das leis de gravitação", explicou Guzzo.
Da AFP
Leila Ossola
Rio de Janeiro-RJ
.
__,_._,___
Surprises from Mercury
NASA's MESSENGER spacecraft has beamed back some surprising new data from the planet Mercury. Highlights include a weird crater nicknamed "the Spider," a planetary tail of hydrogen atoms, and measurements that show giant Caloris basin is even bigger than researchers imagined.
FULL STORY at
http://science.nasa.gov/headlines/y2008/30jan_mercurysurprise.htm?list1073279
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Lucimary Vargas
Além Paraíba-MG-Brasil
observatorio.monoceros@gmail.com
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