Astronomy blog




March 15, 2011, 7:35 AM CT

Hubble Rules Out One Alternative to Dark Energy

Hubble Rules Out One Alternative to Dark Energy
The brilliant, blue glow of young stars trace the graceful spiral arms of galaxy NGC 5584 in this Hubble Space Telescope image. Thin, dark dust lanes appear to be flowing from the yellowish core, where older stars reside. The reddish dots sprinkled throughout the image are largely background galaxies. Credit: NASA, ESA, A. Riess (STScI/JHU), L. Macri (Texas A&M University), and Hubble Heritage Team (STScI/AURA)
Astronomers using NASA's Hubble Space Telescope have ruled out an alternate theory on the nature of dark energy after recalculating the expansion rate of the universe to unprecedented accuracy.

The universe may be expanding at an increasing rate. Some think that is because the universe is filled with a dark energy that works in the opposite way of gravity. One alternative to that hypothesis is that an enormous bubble of relatively empty space eight billion light-years across surrounds our galactic neighborhood. If we lived near the center of this void, observations of galaxies being pushed away from each other at accelerating speeds would be an illusion.

This hypothesis has been invalidated because astronomers have refined their understanding of the universe's present expansion rate. Adam Riess of the Space Telescope Science Institute (STScI) and Johns Hopkins University in Baltimore, Md., led the research. The Hubble observations were conducted by the SHOES (Supernova Ho for the Equation of State) team that works to refine the accuracy of the Hubble constant to a precision that allows for a better characterization of dark energy's behavior. The observations helped determine a figure for the universe's current expansion rate to an uncertainty of just 3.3 percent. The new measurement reduces the error margin by 30 percent over Hubble's prior best measurement of 2009. Riess' results appear in the April 1 issue of The Astrophysical Journal.........

Posted by: Edwin      Read more         Source


September 25, 2010, 8:23 AM CT

"Coreshine" sheds light on the birth of stars

The molecular cloud CB 244 in the constellation Cepheus, 650 light-years from Earth. In such clouds, the Milky Way's light is scattered in different ways: Visible light is predominantly scattered by small grains of dust in the cloud's outer regions ("cloudshine"). The false-colour image shows mid-infrared light scattered by larger grains of dust in the interior of the cloud, the newly discovered "coreshine".
Stars are formed as the dense core regions of cosmic clouds of gas and dust ("molecular clouds") collapse under their own gravity. As a result, matter in these regions becomes ever denser and hotter until finally nuclear fusion is ignited: a star is born. This is how our own star, the Sun, came into being; the fusion processes are responsible for the Sun's light, on which life on Earth depends. The dust grains contained in the collapsing clouds are the raw material out of which an interesting by-product of star formation is made: solar systems and Earth-like planets.

What happens during the earliest phases of this collapse is largely unknown. Enter an international team of astronomers led by Laurent Pagani (LERMA, Observatoire de Paris) and J├╝rgen Steinacker (Max Planck Institute for Astronomy, Heidelberg, Gera number of), who have discovered a new phenomenon which promises information about the crucial earliest phase of the formation of stars and planets: "coreshine", the scattering of mid-infrared light (which is ubiquitous in our galaxy) by dust grains inside such dense clouds. The scattered light carries information about the size and density of the dust particles, about the age of the core region, the spatial distribution of the gas, the prehistory of the material that will end up in planets, and about chemical processes in the interior of the cloud.........

Posted by: Edwin      Read more         Source


August 26, 2010, 11:00 PM CT

Two Planets Transiting Same Star

Two Planets Transiting Same Star
This artist's concept illustrates the two Saturn-sized planets discovered by NASA's Kepler mission. The star system is oriented edge-on, as seen by Kepler, such that both planets cross in front of, or transit, their star. This is the first star system found to have multiple transiting planets.
Credit: NASA/Ames/JPL-Caltech
NASA's Kepler Mission has discovered the first confirmed planetary system with more than one planet transiting the same star.

Today's announcement of the discovery of the two planets, Kepler 9b and 9c, is based on seven months of observations of more than 156,000 stars being monitored for subtle brightness changes as part of an ongoing search for Earth-like planets outside our solar system. Researchers designated the sun-like star Kepler-9.

The inner world, Kepler 9-b, orbits its star every 19.2 days at a distance of 13 million miles, while the outer world orbits once in 38.9 days at a distance of 21 million miles. (In comparison, Mercury has an orbital period of 88 days.) They orbit nearly in resonance, with the inner planet completing two orbits for every one of the outer planet. Both are Saturn-sized gas giants, with the inner world weighing in at 0.25 Jupiter mass (80 Earths) while the outer world is a slimmer 0.17 Jupiter mass (54 Earths).

"This is the first confirmed system of more than one planet transiting the same star," said Matthew Holman, a Kepler Mission scientist from the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass. Researchers confirmed the multiple transits with radial velocity observations conducted at the W.M Keck Observatory in Hawaii.........

Posted by: Edwin      Read more         Source


August 26, 2010, 7:06 AM CT

Why are sunspots a source of radio emissions?

Why are sunspots a source of radio emissions?
Why sunspots are a strong source of radio emissions and what information those emissions carry will be the focus of an invited talk by NJIT Research Professor Jeongwoo Lee.

Credit: New Jersey Institute of Technology
Why sunspots are a strong source of radio emissions and what information those emissions carry will be the focus of an invited talk by NJIT Research Professor Jeongwoo Lee tomorrow at the International Astronomical Union Symposium on the Physics of Sun and Star Spots in Ventura, CA. http://www.csun.edu/physicsandastronomy/IAUS273/ The event numbers among the top gatherings in the U.S. for people studying sunspots and related phenomena.

Lee, who will speak Aug. 26, 2010, will highlight Owens Valley Solar Array (OVSA), one of the two unique frequency-agile radio telescopes in the world. NJIT has managed and operated the facility since 1997. Research opportunities there coupled with Lee's earlier article-- "Radio Emissions from Solar Active Regions" Space Science Reviews, Vol. 133, 73-102 http://www.springerlink.com/content/6533674378432313/ --will be the foundation for the talk.

Owens Valley Solar Array features an uncommonly large number of frequencies (up to 86) in the range of 118 GHz, which can exploit the unique sensitivity of the gyroresonant spectrum to coronal magnetic fields. The imaging spectroscopy (a technique for constructing spectrum in every spatial point of interest) of sunspots implemented with the OVSA is one of the best examples for unambiguous observational determination of the coronal magnetic field and temperature.........

Posted by: Edwin      Read more         Source


December 11, 2007, 8:35 PM CT

Software Helps Mars Rovers Find Winter Havens

Software Helps Mars Rovers Find Winter Havens
Ron Li
New software is helping NASA find safe places for the Spirit rover to ride out future Martian winters -- and also plan where Spirit and its companion rover, Opportunity, will explore in the future.

The steep Martian mesa dubbed "Von Braun" would be a safe haven, the software and data analysis determined -- but the path that Spirit would have to follow to get there is a little too risky to travel with winter on the way, explained Ron Li, professor of civil and environmental engineering and geodetic science at Ohio State University.

That's one reason why Spirit is currently headed to the northern rim of a depression called "Home Plate" for the winter -- though, as of early December, it was rolling through loose soil that was hampering its progress.

Li and his research team are in the process of developing several software programs to help the rovers navigate. The latest program used satellite images, as well as rover images, to determine that Von Braun's more than 25-degree incline is steep enough for the rover's solar panels to gather critical energy from the low winter sun. But it also determined that there are no safe winter sites on the route to Von Braun where the rover could hide out in a pinch.

Should Spirit set out on the 400-foot journey to Von Braun and not be able to reach it, there are not enough bail out spots along the route where it could take refuge, the software found. Even in ideal driving conditions, the trip would take many days. And with the winter approaching, Spirit might need to stop at steep slopes where it could better angle its solar panels to gather light.........

Posted by: Edwin      Read more         Source


December 7, 2007, 9:33 PM CT

James Webb Space Telescope Testing

James Webb Space Telescope Testing
A model of the James Webb Space Telescope's Mid-InfraRed Instrument will be tested before Christmas at the Rutherford Appleton Laboratory in Oxfordshire, England to ensure the final instrument can see infrared light.

Observing the universe in the infrared light portion of the spectrum is important because a number of objects researchers want to observe in space are far too cold to radiate at shorter wavelengths that can be seen as visible light, but they radiate strongly in infrared light.

The Mid-InfraRed Instrument (MIRI) is one of four sophisticated instruments onboard the Webb telescope which will study the early universe and properties of materials forming around new born stars in unprecedented detail. It will also be able to image directly massive planets orbiting other stars.

Speaking at the 3rd Appleton Space Conference on Dec. 6, European Consortium Lead for MIRI, Dr. Gillian Wright from the U.K. Astronomy Technology Centre (ATC) in Edinburgh said, "It is extremely exciting, after working on the project since 1998, to begin to test a complete instrument. This will provide researchers with real data which they can use to understand the best ways of making discoveries with the instrument".

MIRI's development is an effort between NASA and the European Space Agency (ESA). NASA's Jet Propulsion Laboratory in Pasadena (JPL), Calif, leads the NASA effort and is responsible for the development of MIRI's detectors, its cryocooler, and flight software.........

Posted by: Edwin      Read more         Source


October 24, 2007, 7:27 PM CT

NASA Views Southern California Fires and Winds

NASA Views Southern California Fires and Winds
With a click of the mouse button, the public can see NASA views from space, including some at Google Earth, of Southern California's raging wildfires and the ferocious Santa Ana winds that are driving them.

Images taken by the Moderate Resolution Imaging Spectroradiometer (Modis) on NASA's Terra and Aqua satellites are processed daily and made available by the JPL OnEarth Web Map Server, and at Google Earth. This effort is part of an ongoing collaboration with JPL, Google Earth, and NASA Ames Research Center, Moffett Field, Calif., to make remote satellite imagery available to the public and decision makers. Latest Modis fire images at onearth.jpl.nasa.gov/socalfires.........

Posted by: Edwin      Read more         Source


October 23, 2007, 10:04 PM CT

Fifty Times sharper than Hubble

Fifty Times sharper than Hubble
The Inner Jet of the Radio Galaxy M87 located in the Virgo cluster. The angular resolution of this false-color radio image observed by the VLBA at 2 cm wavelength is approximately one milli-arcsecond, fifty times better than that of the Hubble Space Telescope at optical wavelengths. The image shows a limb brightened jet and a faint counter-jet. The central gap is consistent with the presence of a fast inner jet which is beamed away from the observer surrounded by a slower moving outer plasma seen by the VLBA.
Image: Y.Y. Kovalev, MPIfR Bonn
M87, the central galaxy of the Virgo cluster in a distance of only 50 million light years, was observed by Yuri Kovalev from the Max Planck Institute for Radio Astronony (MPIfR) in Bonn and colleagues with the VLBA (Very Long Baseline Array) at 2 cm wavelength. The resulting image provides details down to a resolution of one milli-arcsecond, corresponding to a linear resolution of only three light months. The new image of the inner radio jet of M87 shows a highly collimated jet which appears limb-brightened, and also a faint counter-jet. It is unprecedented in its combination of sensitivity and spatial resolution.

The observations were performed with the Very Long Baseline Array (VLBA) of the National Radio Astronomy Observatory (NRAO), consisting of ten radio antennas in North America including Hawaii and Virgin Island and an additional telescope from the Very Large Array (VLA) near Socorro, New Mexico. The Effelsberg 100m radio telescope is regularly used for transatlantic baselines extending the VLBA observations. "With the 100m radio telescope, we plan to increase the spatial resolution and provide an even more detailed image of the M87 jet", says Yuri Kovalev.........

Posted by: Edwin      Read more         Source


August 3, 2007, 9:54 PM CT

Satellite Data Can Warn Of Famine

Satellite Data Can Warn Of Famine
A NASA researcher has developed a new method to anticipate food shortages brought on by drought. Molly Brown of NASAs Goddard Space Flight Center in Greenbelt, Md., and her colleagues created a model using data from satellite remote sensing of crop growth and food prices.

Brown conceived the idea while working with organizations in Niger, West Africa, that provide information regarding failed crops and help address local farmers' worries about feeding their families. Brown's new approach could improve the ability for government and humanitarian aid officials to plan and respond to drought-induced food price increases in Niger and elsewhere.

Supply and demand largely dictate food prices, with greater supply leading to lower prices and less supply leading to higher prices. During a food crisis in semi-arid regions like Niger, food shortages are often brought on when lack of rainfall significantly reduces the amount of grain farmers are able to grow. Farmers in regions like Niger are able only to grow a few drought-resistant crops, and therefore must buy grain at unaffordably high prices at the end of the year to make up for shortfalls in production. This scenario could drive a drought-driven food security crisis. A lack of locally-produced and affordable grain, coupled with increased prices and reduced access to food, could lead to starvation and hunger-related illness in the most vulnerable segments of society.........

Posted by: Edwin      Read more         Source


July 30, 2007, 9:43 PM CT

First ALMA Transporter Ready to Go

First ALMA Transporter Ready to Go
Transporting an ALMA Antenna (Artist's Impression)

The first of two spectacular vehicles for the ALMA (Atacama Large Millimeter/submillimeter Array) Observatory rolled out of its hangar and passed successfully a series of tests. This vehicle, the ALMA antenna transporter, is a rather exceptional 'lorry' driving on 28 tyres. It is 10m wide, 20m long and 6m high, weighs 130 tons and has as much power as two Formula 1 engines. This colossus will be able to transport a 115-ton antenna and set it down on a concrete pad within millimetres of a prescribed position.

The ALMA Project is a giant, international observatory currently in construction on the high-altitude Chajnantor site in Chile, and composed initially of 66 high-precision telescopes, operating at wavelengths of 0.3 to 9.6 mm. The ALMA antennas will be electronically combined and provide astronomical observations which are equivalent to a single large telescope of tremendous size and resolution. ALMA will be able to probe the Universe at millimetre and submillimetre wavelengths with unprecedented sensitivity and resolution, with an accuracy up to ten times better than the Hubble Space Telescope, and complementing images made with ESO's Very Large Telescope Interferometer.

The telescopes can be moved across the high-altitude desert Chajnantor plateau, covering antenna configurations as compact as 150 metres to as wide as 15 kilometres. Changing the relative positions of the antennas and thus also the configuration of the array allows for different observing modes, comparable to using a zoom lens on a camera.........

Posted by: Edwin      Read more         Source


July 4, 2007, 5:05 AM CT

Stellar fireworks are ablaze in galaxy NGC 4449

Stellar fireworks are ablaze in galaxy NGC 4449
Credit: NASA, ESA, A. Aloisi (STScI/ESA), and The Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration
Hundreds of thousands of vibrant blue and red stars are visible in this new image of galaxy NGC 4449 taken by the NASA/ESA Hubble Space Telescope. Hot bluish white clusters of massive stars are scattered throughout the galaxy, interspersed with numerous dustier reddish regions of current star formation. Massive dark clouds of gas and dust are silhouetted against the flaming starlight.

NGC 4449 has been forming stars since several billion years ago, but currently it is experiencing a star formation event at a much higher rate than in the past. This unusual explosive and intense star formation activity qualifies as a starburst. At the current rate, the gas supply that feeds the stellar production would only last for another billion years or so.

Starbursts commonly occur in the central regions of galaxies, but NGC 4449 has a more widespread star formation activity, since the very youngest stars are observed both in the nucleus and in streams surrounding the galaxy.

A "global" starburst like NGC 4449 resembles primordial star forming galaxies which grew by merging with and accreting smaller stellar systems. Since NGC 4449 is close enough to be observed in great detail, it is the ideal laboratory for the investigation of what may have occurred during galactic formation and evolution in the early Universe.........

Posted by: Edwin      Read more         Source


June 20, 2007, 10:55 AM CT

Case researchers may have solved

Case researchers may have solved
"Nothing there," is what Case Western Reserve University physicists concluded about black holes after spending a year working on complex formulas to calculate the formation of new black holes. In nearly 13 printed pages with a host of calculations, the research may solve the information loss paradox that haccording toplexed physicists for the past 40 years.

Case physicists Tanmay Vachaspati, Dejan Stojkovic and Lawrence M. Krauss report in the article, "Observation of Incipient Black Holes and the Information Loss Problem, that has been accepted for publication by Physical Review D.

"It's complicated and very complex," noted the researchers, regarding both the general problem and their particular approach to try to solve it.

The question that the physicists set out to solve is: what happens once something collapses into a black hole" If all information about the collapsing matter is lost, it defies the laws of quantum physics. Yet, in current thinking, once the matter goes over the event horizon and forms a black hole, all information about it is lost.

"If you define the black hole as some place where you can lose objects, then there is no such thing because the black hole evaporates before anything is seen to fall in," said Vachaspati.........

Posted by: Edwin      Read more         Source


May 14, 2007, 10:47 PM CT

Cluster makes a shocking discovery

Cluster makes a shocking discovery
The image shows a bow shock around the very young star, LL Ori.
ESA's Cluster was in the right place and time to make a shocking discovery. The four spacecraft encountered a shock wave that kept breaking and reforming - predicted only in theory.

On 24 January 2001, Cluster's spacecraft observed shock reformation in the Earth's magnetosphere, predicted only in theory, over 20 years ago. Cluster provided the first opportunity ever to observe such an event, the details of which have been published in a paper on 9 March this year.

The shock wave that sits above the Earth's surface is a natural phenomenon. It is located on the side facing the Sun, at approximately one quarter of the distance to the Moon, and is caused by the flow of electrically charged particles from the Sun.

This flow of electrically charged particles known as solar wind is emitted in a gusty manner by the Sun. When it collides with the Earth's magnetic field, it is abruptly slowed down and this causes a barrier of electrified gas, called the bow shock, to build up. It behaves in the same way as water being pushed out of the way by the front of a ship.

On 24 January 2001, the four Cluster spacecraft were flying at an approximate altitude of 105 000 kilometres, in tetrahedron formation. Each spacecraft was separated from the others by a distance of about 600 kilometres. With such a distance between them, as they approached the bow shock, researchers expected that every spacecraft would record a similar signature of the passage through this region.........

Posted by: Edwin      Read more         Source


April 24, 2007, 10:40 PM CT

Back to the Moon

Back to the Moon
Of the two luminaries that dominate our sky, it is the moon that is of particular interest to the Lunar Reconnaissance Orbiter (LRO) project. The LRO will travel to the moon in late fall 2008, mapping the surface to help pave the way for humans to return. It will help prepare us for extended surface exploration on the moon and for subsequent missions to Mars and other distant destinations. Lunar surface exploration will help us to practice living, working, and gathering science data before we venture into riskier territory.

The Lunar Reconnaissance Orbiter will take the first strides in researching a complex habitat -- a hostile environment without atmosphere or clouds, with daytime temperatures reaching as high as 250 degrees Fahrenheit (123 degrees Celsius) and as low as minus 450 degrees Fahrenheit (233 degrees Celsius), and sunlight lasting two weeks. The spacecraft will identify the volatile terrain so we can land safely. It should also be able to identify water on the surface, if it sees it.

The spacecraft being built at NASA's Goddard Space Flight Center in Greenbelt, Md., will include six instruments and a technology demonstration. The objective is to collect the highest resolution and most comprehensive data set ever returned from the moon, or gathered by any planetary mission, to help achieve NASA's goal of returning human explorers safely to the moon. The data gathered by instruments on the Lunar Reconnaissance Orbiter will provide more information than all six Apollo surface missions managed to produce. While the Apollo missions focused on gaining science from the band around the moon's equator, the Lunar Reconnaissance Orbiter will circle the poles. It will spend at least one year in low, polar orbit, with all the instruments working simultaneously to collect detailed information about the lunar environment. Data sets will be deposited in the publicly accessible Planetary Data System within six months of its primary mission completion.........

Posted by: Edwin      Read more         Source


April 11, 2007, 9:20 PM CT

Nongreen Plants On Other Planets

Nongreen Plants On Other Planets
NASA scientists believe they have found a way to predict the color of plants on planets in other solar systems.

Green, yellow or even red-dominant plants may live on extra-solar planets, according to scientists whose two scientific papers appear in the recent issue of the journal, Astrobiology. The scientists studied light absorbed and reflected by organisms on Earth, and determined that if astronomers were to look at the light given off by planets circling distant stars, they might predict that some planets have mostly non-green plants.

"We can identify the strongest candidate wavelengths of light for the dominant color of photosynthesis on another planet," said Nancy Kiang, lead author of the study and a biometeorologist at NASA's Goddard Institute for Space Studies, New York. Kiang worked with a team of scientists from the Virtual Planetary Laboratory (VPL) at the California Institute of Technology, Pasadena, Calif. VPL was formed as part of the NASA Astrobiology Institute (NAI), based at the NASA Ames Research Center in California's Silicon Valley.

"This work broadens our understanding of how life may be detected on Earth-like planets around other stars, while simultaneously improving our understanding of life on Earth," said Carl Pilcher, director of the NAI at NASA Ames. "This approach -- studying Earth life to guide our search for life on other worlds -- is the essence of astrobiology".........

Posted by: Edwin      Read more         Source


March 19, 2007, 9:30 PM CT

Most Energetic Form Of Light

Most Energetic Form Of Light
n 2002, when astronomers first detected cosmic gamma rays - the most energetic form of light known - coming from the constellation Cygnus they were surprised and perplexed. The region lacked the extreme electromagnetic fields that they thought were required to produce such energetic rays. But now a team of theoretical physicists propose a mechanism that can explain this mystery and may also help account for another type of cosmic ray, the high-energy nuclei that rain down on Earth in the billions.

The new mechanism is described in a Physical Review Letters paper published online on March 20. The theoretical study was headed by Thomas Weiler, professor of physics at Vanderbilt, working with Luis Anchordoqui at the University of Wisconsin-Milwaukee; John Beacom at Ohio State University; Haim Goldberg at Northeastern University; and Sergio Palomares-Ruiz at the University of Durham.

Existing methods for producing cosmic gamma rays require the ultra-strong electromagnetic fields found only in some of the most extreme conditions in the universe, such as stellar explosions and regions surrounding the massive black holes found at the core of many galaxies. So they couldn't explain how a "starburst" region in the Cygnus galaxy dominated by young, hot, bright stars could produce such energetic rays. The newly proposed mechanism, however, shows how two constituents present in such an area - fast-moving nuclei found in stellar winds and ultraviolet light - can interact to produce cosmic gamma rays.........

Posted by: Edwin      Read more         Source


March 15, 2007, 9:15 PM CT

Water Quantity Around Mars South Pole

Water Quantity Around Mars South Pole
The amount of water trapped in frozen layers over Mars' south polar region is equivalent to a liquid layer about 11 metres deep covering the planet.

This new estimate comes from mapping the thickness of the dusty ice by the Mars Express radar instrument that has made more than 300 virtual slices through layered deposits covering the pole. The radar sees through icy layers to the lower boundary, which in places is as deep as 3.7 kilometres below the surface.

"The south polar layered deposits of Mars cover an area as wide as a big portion of Europe. The amount of water they contain has been estimated before, but never with the level of confidence this radar makes possible," said Dr. Jeffrey Plaut of NASA's Jet Propulsion Laboratory, Pasadena (California), co-Principal Investigator for the radar and lead author of the study.

The instrument, named the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS), is also mapping the thickness of similar layered deposits at the north pole of Mars.

Our radar is doing its job extremely well, said Prof. Giovanni Picardi of the University of Rome La Sapienza, Principal Investigator for the instrument. MARSIS is showing to be a very powerful tool to probe underneath the Martian surface, and its showing how our teams goals such as probing the polar layered deposits - are being successfully achieved, he continued. Not only MARSIS is providing us with the first ever views of Mars subsurface at those depths, but the details we are seeing are truly amazing. We are expecting even greater results when we will have concluded an on-going, sophisticated fine-tuning of our data processing methods. These should enable us to understand even better the surface and subsurface composition.........

Posted by: Edwin      Read more         Source


February 27, 2007, 8:00 PM CT

About The Extrasolars

About The Extrasolars This artist's concept shows a cloudy Jupiter-like planet, similar to HD 209458b, that orbits very close to its fiery hot star. Image / NASA/JPL-Caltech/T. Pyle (SSC)
So far, astronomers have discovered about 200 planets outside our solar system, known as "extrasolar" planets. Very little is known about most of them, but for the first time, researchers have obtained new information about the atmospheres of two such planets by splitting apart the light emitted from them.

Sara Seager, MIT associate professor of earth, atmospheric and planetary sciences, is part of a research group based at Goddard Space Flight Center that studied a planet about 904 trillion miles from Earth, known as HD 209458b. The scientists used NASA's Spitzer Space Telescope to capture the most detailed information yet about an extrasolar planet.

Seager's team is one of three that are reporting spectral observations of extrasolar planets this week. Two groups studied HD 209458b, and one studied another planet in a different solar system. The work by Seager's team is published in the Feb. 22 issue of Nature.

Astronomers often learn about distant objects, such as stars and galaxies, by studying the composition of light emitted by them, Seager said. But extrasolar planets are much dimmer than stars and thus far more difficult to study.

Light from extrasolar planets is "very, very hard to measure because the stars are so bright and the planets are faint. This planet is right at the edge of what we can detect with this telescope," said Seager, who arrived at MIT in January to start a program devoted to studying extrasolar planets.........

Posted by: Edwin      Read more         Source


February 26, 2007, 7:10 PM CT

South Pole Telescope achieves first light

South Pole Telescope achieves first light
Researchers aimed the South Pole Telescope at Jupiter on the evening of Feb. 16 and successfully collected the instrument's first test observations. Soon, far more distant quarry will fall under the SPT's sights as a team from nine institutions tackles one of the.

biggest mysteries of modern cosmological research. That mystery: What is dark energy, the force that dominates the universe?

"The telescope, camera and optics are all working as.

designed," said John Carlstrom, the S. Chandrasekhar Distinguished Service Professor in Astronomy & Astrophysics at the University of.

Chicago, who heads the SPT Team. "First light with the SPT is a major milestone for the project and is a fitting conclusion to a remarkably productive summer season for the South Pole Station. We now look.

forward to fully characterizing the instrument and beginning cosmological observations," he said.

The $19.2 million SPT is funded primarily by the National Science Foundation, with additional support from the Kavli Foundation of Oxnard, Calif., and the Gordon and Betty Moore Foundation of San Francisco.

The telescope stands 75 feet tall, measures 33 feet across and weighs 280 tons. It was test-built in Kilgore, Texas, then taken apart, shipped by boat to New Zealand, and flown to the South Pole. Since November, the SPT team under the guidance of project manager Steve Padin, Senior Scientist in Astronomy & Astrophysics at the University of Chicago, has worked furiously to reassemble and deploy the telescope.........

Posted by: Edwin      Read more         Source


February 20, 2007, 8:45 PM CT

Formation of auroras

Formation of auroras Auroras form in high latitude regions of Earth, and appear in many different shapes.
Credits: Jan Curtis, Fairbanks, Alask
Giant electrical circuits power the magical open-air light show of the auroras, forming arcs in high-latitude regions like Scandinavia. New results obtained thanks to ESA's Cluster satellites provide a new insight into the source of the difference between the two types of electrical circuits currently known to be associated to the auroral arcs.

The deep mechanisms that rule the creation of the beautiful auroras, or polar lights, have been the subject of studies that are keeping solar and plasma researchers busy since years. While early rockets and ground-observations have already provided a few important clues for the understanding of these phenomena, the real break-throughs in our knowledge have started with dedicated auroral satellites, such as S3-3, Dynamics Explorer, Viking, Freja and FAST, and have now come to full fruition with ESA's multi-point mission Cluster.

The basic process generating auroras is similar to what happens in an old TV tube. In the TV tube, accelerated electrons hit the screen and make its phosphore glow; electrons in the atmosphere get accelerated in an 'acceleration region' situated between about 5000 and 8000 kilometres altitude, and rush down to the Earth's ionosphere - a region of the upper atmosphere. Here, they crash into ionospheric atoms and molecules, transfer to them some of their energy and so cause them to glow, creating aurorae.........

Posted by: Edwin      Read more         Source


February 19, 2007, 8:27 PM CT

Where is Beagle 2?

Where is Beagle 2?
NASA's Mars Reconnaissance Orbiter (MRO) spacecraft has used its onboard High Resolution Imaging Science Experiment camera (HiRISE) to take a colour image of a region of Mars in the vicinity of the intended landing site of Beagle 2.

H20 crater.

Credit: NASA's Mars Reconnaissance OrbiterIncluded in the image is new coverage of the crater H2O which was considered by the Beagle 2 team as unique in the area that had been searched for evidence of the missing Lander. Beagle 2 was targeted to land in an ellipse approximately 50km x 10km in size.

The new image does not show any features inside the crater that can be reconciled with peculiarities (i.e. possible components of the entry descent and landing system) encountered in the two prior lower resolution images taken soon after Beagle 2 was due to arrive on Mars in December 2003. The prior images were captured by the Mars Orbiter Camera on NASA's Mars Global Surveyor spacecraft.

Commenting on the latest image, Prof Colin Pillinger of the Open University and lead scientist for Beagle 2, said "Of course this is disappointing. We had hoped that the HiRISE camera would clarify the oddities we had seen in the crater but this is not the case. Nevertheless, I am extremely grateful to the camera team at NASA's Jet Propulsion Laboratory and the University of Arizona for trying and congratulate them on the exceptional quality of the images. I remain optimistic that future images may yet show us where Beagle 2 finally came to rest".........

Posted by: Edwin      Read more         Source


February 8, 2007, 8:48 PM CT

Cosmic graffiti artist

Cosmic graffiti artist
Astronomers from the University of Virginia and other institutions have observed that Enceladus, the sixth-largest moon of Saturn, is a "cosmic graffiti artist," pelting the surfaces of at least 11 other moons of Saturn with ice particles sprayed from its spewing surface geysers. This ice sandblasts the other moons, creating a reflective surface that makes them among the brightest bodies in the solar system (Enceladus, itself a ball of mostly ice, is the single most reflective body in our solar system).

"Enceladus' art is a work-in-progress, constantly altering the surfaces of other moons orbiting within this moon's beautiful swirl of ice particles," said Anne Verbiscer, a research scientist in the astronomy department at the University of Virginia and the study's lead investigator. "We've dubbed Enceladus a graffiti artist because of its ability to alter the appearance of the other moons".

A paper about her and her colleagues' findings appears in the Feb. 9 issue of the journal Science.

The ring of ice particles Enceladus forms around Saturn is known as the E-ring. At least 11 other moons orbit within the E-ring and are constantly subjected to high velocity collisions with Enceladus's icy wake.

A series of geysers at Enceladus's south pole continually erupt, ejecting ice particles, spewing a swirling wispy trail in the moon's wake and ultimately forming a cloudy ring of ice particles. The ring is added to over and over as Enceladus repeats its orbit. The particles may persist for thousands of years, until they collide with one of the embedded moons, including Enceladus as it flows through its own emissions.........

Posted by: Edwin      Read more         Source

 
Older Blog Entries   1   2   3   4   5   6   7   8   9   10   11   12   13   14   15   16   17   18   19   20  

New technology blog Computer science Health news blog Biology blog
Psychology Blog Media Blog Astronomy Blog Science Blog
Future Blog