Nearby planet-forming disk holds water for thousands of oceans

ScienceDaily (Oct. 20, 2011) — For the first time, astronomers have detected around a burgeoning solar system a sprawling cloud of water vapor that's cold enough to form comets, which could eventually deliver oceans to dry planets.

Water is an essential ingredient for life. Scientists have found thousands of Earth-oceans' worth of it within the planet-forming disk surrounding the star TW Hydrae. TW Hydrae is 176 light years away in the constellation Hydra and is the closest solar-system-to-be.

University of Michigan astronomy professor Ted Bergin is a co-author of a paper on the findings published in the Oct. 21 edition of Science.

The researchers used the Heterodyne Instrument for the Far-Infrared (HIFI) on the orbiting Hershel Space Observatory to detect the chemical signature of water.

"This tells us that the key materials that life needs are present in a system before planets are born," said Bergin, a HIFI co-investigator. "We expected this to be the case, but now we know it is because have directly detected it. We can see it."

Scientists had previously found warm water vapor in planet-forming disks close to the central star. But until now, evidence for vast quantities of water extending into the cooler, far reaches of disks where comets and giant planets take shape had not emerged. The more water available in disks for icy comets to form, the greater the chances that large amounts will eventually reach new planets through impacts.

"The detection of water sticking to dust grains throughout the planet-forming disk would be similar to events in our own solar system's evolution, where over millions of years, these dust grains would then coalesce to form comets. These would be a prime delivery mechanism for water on planetary bodies," said principal investigator Michiel Hogerheijde of Leiden University in the Netherlands.

Other recent findings from HIFI support the theory that comets delivered a significant portion of Earth's oceans. Researchers found that the ice on a comet called Hartley 2 has the same chemical composition as our oceans.

HIFI is helping astronomers gain a better understanding of how water comes to terrestrial planets -- Earth and beyond. If TW Hydrae and its icy disk are representative of many other young star systems, as researchers think they are, then the process for creating planets around numerous stars with abundant water throughout the universe appears to be in place, NASA officials say.

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Journal Reference:

M. R. Hogerheijde, E. A. Bergin, C. Brinch, L. I. Cleeves, J. K. J. Fogel, G. A. Blake, C. Dominik, D. C. Lis, G. Melnick, D. Neufeld, O. Panic, J. C. Pearson, L. Kristensen, U. A. Yildiz, E. F. van Dishoeck. Detection of the Water Reservoir in a Forming Planetary System. Science, 2011; 334 (6054): 338 DOI: 10.1126/science.1208931

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iPhone turned into spiPhone: Smartphone senses nearby keyboard vibrations and deciphers sentences

ScienceDaily (Oct. 18, 2011) — It's a pattern that no doubt repeats itself daily in hundreds of millions of offices around the world: People sit down, turn on their computers, set their mobile phones on their desks and begin to work. What if a hacker could use that phone to track what the person was typing on the keyboard just inches away?

A research team at Georgia Tech has discovered how to do exactly that, using a smartphone accelerometer -- the internal device that detects when and how the phone is tilted -- to sense keyboard vibrations and decipher complete sentences with up to 80 percent accuracy. The procedure is not easy, they say, but is definitely possible with the latest generations of smartphones.

"We first tried our experiments with an iPhone 3GS, and the results were difficult to read," said Patrick Traynor, assistant professor in Georgia Tech's School of Computer Science. "But then we tried an iPhone 4, which has an added gyroscope to clean up the accelerometer noise, and the results were much better. We believe that most smartphones made in the past two years are sophisticated enough to launch this attack."

Previously, Traynor said, researchers have accomplished similar results using microphones, but a microphone is a much more sensitive instrument than an accelerometer. A typical smartphone's microphone samples vibration roughly 44,000 times per second, while even newer phones' accelerometers sample just 100 times per second -- two full orders of magnitude less often. Plus, manufacturers have installed security around a phone's microphone; the phone's operating system is programmed to ask users whether to give new applications access to most built-in sensors, including the microphone. Accelerometers typically are not protected in this way.

The technique works through probability and by detecting pairs of keystrokes, rather than individual keys (which still is too difficult to accomplish reliably, Traynor said). It models "keyboard events" in pairs, then determines whether the pair of keys pressed is on the left versus right side of the keyboard, and whether they are close together or far apart. After the system has determined these characteristics for each pair of keys depressed, it compares the results against a preloaded dictionary, each word of which has been broken down along similar measurements (i.e., are the letters left/right, near/far on a standard QWERTY keyboard). Finally, the technique only works reliably on words of three or more letters.

For example, take the word "canoe," which when typed breaks down into four keystroke pairs: "C-A, A-N, N-O and O-E." Those pairs then translate into the detection system's code as follows: Left-Left-Near, Left-Right-Far, Right-Right-Far and Right-Left-Far, or LLN-LRF-RRF-RLF. This code is then compared to the preloaded dictionary and yields "canoe" as the statistically probable typed word. Working with dictionaries comprising about 58,000 words, the system reached word-recovery rates as high as 80 percent.

"The way we see this attack working is that you, the phone's owner, would request or be asked to download an innocuous-looking application, which doesn't ask you for the use of any suspicious phone sensors," said Henry Carter, a PhD student in computer science and one of the study's co-authors. "Then the keyboard-detection malware is turned on, and the next time you place your phone next to the keyboard and start typing, it starts listening."

Mitigation strategies for this vulnerability are pretty simple and straightforward, Traynor said. First, since the study found an effective range of just three inches from a keyboard, phone users can simply leave their phones in their purses or pockets, or just move them further away from the keyboard. But a fix that puts less onus on users is to add a layer of security for phone accelerometers.

"The sampling rate for accelerometers is already pretty low, and if you cut it in half, you start to approach theoretical limitations that prevent eavesdropping. The malware simply does not have the data to work with," Traynor said. "But most phone applications can still function even with that lower accelerometer rate. So manufacturers could set that as the default rate, and if someone downloads an application like a game that needs the higher sampling rate, that would prompt a permission question to the user to reset the accelerometer."

In the meantime, Traynor said, users shouldn't be paranoid that hackers are tracking their keystrokes through their iPhones.

"The likelihood of someone falling victim to an attack like this right now is pretty low," he said. "This was really hard to do. But could people do it if they really wanted to? We think yes."

The finding is reported in the paper, "(sp)iPhone: Decoding Vibrations From Nearby Keyboards Using Mobile Phone Accelerometers," and will be presented on Oct. 20, at the 18th ACM Conference on Computer and Communications Security in Chicago. In addition to Carter, Traynor's coauthors include Georgia Tech graduate student Arunabh Verman and Philip Marquardt of the MIT Lincoln Laboratory.

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Note: If no author is given, the source is cited instead.

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How the Milky Way killed off nearby galaxies

ScienceDaily (Oct. 18, 2011) — Two researchers from Observatoire Astronomique de Strasbourg have revealed for the first time the existence of a new signature of the birth of the first stars in our galaxy, the Milky Way. More than 12 billion years ago, the intense ultraviolet light from these stars dispersed the gas of our Galaxy's nearest companions, virtually putting a halt to their ability to form stars and consigning them to a dim future. Now Pierre Ocvirk and Dominique Aubert, members of the Light in the Dark Ages of the Universe (LIDAU) collaboration, have explained why some galaxies were killed off, while stars continued to form in more distant objects.

The two scientists publish their results in the October issue of the letters of the journal Monthly Notices of the Royal Astronomical Society.

The first stars of the Universe appeared about 150 million years after the Big Bang. Back then, the hydrogen and helium gas filling the universe was cold enough for its atoms to be electrically neutral. As the ultraviolet (UV) light of the first stars propagated through this gas, it broke apart the proton-electron pairs that make up hydrogen atoms, returning them to the so-called plasma state they experienced in the first moments of the Universe. This process, known as reionisation, also resulted in significant heating, which had dramatic consequences: the gas became so hot that it escaped the weak gravity of the lowest mass galaxies, thereby depriving them of the material needed to form stars.

It is now widely accepted that this process can explain the small number and large ages of the stars seen in the faintest dwarf galaxy satellites of the Milky Way. It also helps scientists understand why galaxies like the Milky Way have so few satellites around them -- the 'missing satellites' problem. The stripping out of gas from these galaxies makes them sensitive probes of the UV radiation in the reionisation epoch.

The satellite galaxies are also relatively close, from 30000 to 900000 light-years away, which allows us to study them in great detail, something that will be enhanced by the coming generation of larger telescopes. Comparing the population of their stars in each galaxy with its position could give us a unique insight into the structure of the UV radiation emitted from the earliest stars in the Milky Way.

Until now, models for this process assumed that the radiation leading to the removal of gas from galaxy satellites was produced collectively by all the large galaxies nearby, resulting in a uniform background of UV light. The new model put together by the two French researchers proves this assumption wrong.

Ocvirk and Aubert looked at the way the invisible 'dark matter' that makes up about 23% of the Universe structured itself with the stars in our Galaxy and its environs from shortly after the Big Bang to the present day. They used the high resolution numerical simulation Via Lactea II to model the formation of stars in gas trapped in the dark matter haloes that envelop galaxies, and then to describe how this gas reacted to UV radiation.

Pierre Ocvirk comments, "This is the first time that a model accounts for the effect of the radiation emitted by the first stars formed at the centre of the Milky Way on its satellite galaxies.

'In contrast to previous models, the radiation field produced is not uniform, but decreases in intensity as one moves away from the centre of the Milky Way.

'The satellite galaxies close to the galactic centre see their gas evaporate very quickly. They form so few stars that they can be undetectable with current telescopes. At the same time, the more remote satellite galaxies experience on average a weaker irradiation. Therefore they manage to keep their gas longer, and form more stars. As a consequence they are easier to detect and appear more numerous."

The new model appears to be a close match to observations of our Galaxy and its neighbourhood and suggests that the first stars of our galaxy played a major role in the photo-evaporation of the satellite galaxies' gas, adds Dr Ocvirk. "It is not large nearby galaxies but our own that caused the demise of its tiny neighbours, asphyxiating them through its intense radiation."

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The above story is reprinted from materials provided by Royal Astronomical Society (RAS).

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Journal Reference:

Pierre Ocvirk, Dominique Aubert. A signature of the internal reionisation of the Milky Way? Monthly Notices of the Royal Astronomical Society, 2011 [link]

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View the original article here

Nearby planet-forming disk holds water for thousands of oceans

ScienceDaily (Oct. 20, 2011) — For the first time, astronomers have detected around a burgeoning solar system a sprawling cloud of water vapor that's cold enough to form comets, which could eventually deliver oceans to dry planets.

Water is an essential ingredient for life. Scientists have found thousands of Earth-oceans' worth of it within the planet-forming disk surrounding the star TW Hydrae. TW Hydrae is 176 light years away in the constellation Hydra and is the closest solar-system-to-be.

University of Michigan astronomy professor Ted Bergin is a co-author of a paper on the findings published in the Oct. 21 edition of Science.

The researchers used the Heterodyne Instrument for the Far-Infrared (HIFI) on the orbiting Hershel Space Observatory to detect the chemical signature of water.

"This tells us that the key materials that life needs are present in a system before planets are born," said Bergin, a HIFI co-investigator. "We expected this to be the case, but now we know it is because have directly detected it. We can see it."

Scientists had previously found warm water vapor in planet-forming disks close to the central star. But until now, evidence for vast quantities of water extending into the cooler, far reaches of disks where comets and giant planets take shape had not emerged. The more water available in disks for icy comets to form, the greater the chances that large amounts will eventually reach new planets through impacts.

"The detection of water sticking to dust grains throughout the planet-forming disk would be similar to events in our own solar system's evolution, where over millions of years, these dust grains would then coalesce to form comets. These would be a prime delivery mechanism for water on planetary bodies," said principal investigator Michiel Hogerheijde of Leiden University in the Netherlands.

Other recent findings from HIFI support the theory that comets delivered a significant portion of Earth's oceans. Researchers found that the ice on a comet called Hartley 2 has the same chemical composition as our oceans.

HIFI is helping astronomers gain a better understanding of how water comes to terrestrial planets -- Earth and beyond. If TW Hydrae and its icy disk are representative of many other young star systems, as researchers think they are, then the process for creating planets around numerous stars with abundant water throughout the universe appears to be in place, NASA officials say.

Recommend this story on Facebook, Twitter,
and Google +1:

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Story Source:

The above story is reprinted from materials provided by University of Michigan.

Note: ScienceDaily reserves the right to edit materials for content and length. For further information, please contact the source cited above.

Journal Reference:

M. R. Hogerheijde, E. A. Bergin, C. Brinch, L. I. Cleeves, J. K. J. Fogel, G. A. Blake, C. Dominik, D. C. Lis, G. Melnick, D. Neufeld, O. Panic, J. C. Pearson, L. Kristensen, U. A. Yildiz, E. F. van Dishoeck. Detection of the Water Reservoir in a Forming Planetary System. Science, 2011; 334 (6054): 338 DOI: 10.1126/science.1208931

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

iPhone turned into spiPhone: Smartphone senses nearby keyboard vibrations and deciphers sentences

ScienceDaily (Oct. 18, 2011) — It's a pattern that no doubt repeats itself daily in hundreds of millions of offices around the world: People sit down, turn on their computers, set their mobile phones on their desks and begin to work. What if a hacker could use that phone to track what the person was typing on the keyboard just inches away?

A research team at Georgia Tech has discovered how to do exactly that, using a smartphone accelerometer -- the internal device that detects when and how the phone is tilted -- to sense keyboard vibrations and decipher complete sentences with up to 80 percent accuracy. The procedure is not easy, they say, but is definitely possible with the latest generations of smartphones.

"We first tried our experiments with an iPhone 3GS, and the results were difficult to read," said Patrick Traynor, assistant professor in Georgia Tech's School of Computer Science. "But then we tried an iPhone 4, which has an added gyroscope to clean up the accelerometer noise, and the results were much better. We believe that most smartphones made in the past two years are sophisticated enough to launch this attack."

Previously, Traynor said, researchers have accomplished similar results using microphones, but a microphone is a much more sensitive instrument than an accelerometer. A typical smartphone's microphone samples vibration roughly 44,000 times per second, while even newer phones' accelerometers sample just 100 times per second -- two full orders of magnitude less often. Plus, manufacturers have installed security around a phone's microphone; the phone's operating system is programmed to ask users whether to give new applications access to most built-in sensors, including the microphone. Accelerometers typically are not protected in this way.

The technique works through probability and by detecting pairs of keystrokes, rather than individual keys (which still is too difficult to accomplish reliably, Traynor said). It models "keyboard events" in pairs, then determines whether the pair of keys pressed is on the left versus right side of the keyboard, and whether they are close together or far apart. After the system has determined these characteristics for each pair of keys depressed, it compares the results against a preloaded dictionary, each word of which has been broken down along similar measurements (i.e., are the letters left/right, near/far on a standard QWERTY keyboard). Finally, the technique only works reliably on words of three or more letters.

For example, take the word "canoe," which when typed breaks down into four keystroke pairs: "C-A, A-N, N-O and O-E." Those pairs then translate into the detection system's code as follows: Left-Left-Near, Left-Right-Far, Right-Right-Far and Right-Left-Far, or LLN-LRF-RRF-RLF. This code is then compared to the preloaded dictionary and yields "canoe" as the statistically probable typed word. Working with dictionaries comprising about 58,000 words, the system reached word-recovery rates as high as 80 percent.

"The way we see this attack working is that you, the phone's owner, would request or be asked to download an innocuous-looking application, which doesn't ask you for the use of any suspicious phone sensors," said Henry Carter, a PhD student in computer science and one of the study's co-authors. "Then the keyboard-detection malware is turned on, and the next time you place your phone next to the keyboard and start typing, it starts listening."

Mitigation strategies for this vulnerability are pretty simple and straightforward, Traynor said. First, since the study found an effective range of just three inches from a keyboard, phone users can simply leave their phones in their purses or pockets, or just move them further away from the keyboard. But a fix that puts less onus on users is to add a layer of security for phone accelerometers.

"The sampling rate for accelerometers is already pretty low, and if you cut it in half, you start to approach theoretical limitations that prevent eavesdropping. The malware simply does not have the data to work with," Traynor said. "But most phone applications can still function even with that lower accelerometer rate. So manufacturers could set that as the default rate, and if someone downloads an application like a game that needs the higher sampling rate, that would prompt a permission question to the user to reset the accelerometer."

In the meantime, Traynor said, users shouldn't be paranoid that hackers are tracking their keystrokes through their iPhones.

"The likelihood of someone falling victim to an attack like this right now is pretty low," he said. "This was really hard to do. But could people do it if they really wanted to? We think yes."

The finding is reported in the paper, "(sp)iPhone: Decoding Vibrations From Nearby Keyboards Using Mobile Phone Accelerometers," and will be presented on Oct. 20, at the 18th ACM Conference on Computer and Communications Security in Chicago. In addition to Carter, Traynor's coauthors include Georgia Tech graduate student Arunabh Verman and Philip Marquardt of the MIT Lincoln Laboratory.

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The above story is reprinted from materials provided by Georgia Institute of Technology.

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Note: If no author is given, the source is cited instead.

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View the original article here

Smartphone Accelerometers Could Be Used To Eavesdrop On Nearby Devices

Smartphone Accelerometers Could Be Used To Eavesdrop On Nearby Devices | Popular Science@import "/files/css/1857af3413d9ad8bd2f9d3926af8ec39.css";@import "/files/css/33f6b7ecb4513ed2fe6c670880a27187.css"; home Login/Register Newsletter Subscribe RSS GadgetsComputersCamerasSmartphonesVideo GamesCarsConceptsHybridsElectric CarsScienceFuture of the EnvironmentEnergyHealthPopSci Eco TourTechnologyMilitaryAviationSpaceRobotsEngineeringDIYProjectsHacksToolsAuto DIYMore From Our Partner: Toolmonger GalleriesVideosColumnsThe GrouseSex FilesGreen Dream Innovation ChallengesHow It WorksFeatures Tweet Digg Smartphone Accelerometers Could Be Used To Eavesdrop On Nearby Devices By Rebecca Boyle Posted 10.19.2011 at 11:07 am 3 Comments
SpyPhone Patrick Traynor shows off the "SpiPhone" app he created to tap keystrokes with phone accelerometers. Georgia Tech

As you logged in to write a comment this morning, think about where your smartphone was sitting. Was it next to your keyboard, where you could ensure you didn’t miss any notifications? If so, your phone could track everything you wrote. It could use the accelerometer to detect keyboard vibrations, deciphering every word of your insightful anonymous commentary. A hacker could conceivably use it to find out everything you write, with up to 80 percent accuracy, researchers say.

Here’s how it would work: An accelerometer samples a phone’s vibration about 100 times per second, so it would be able to detect pairs of keystrokes, according to a Georgia Tech news release about this research. It would model “keyboard events” and determine where the pairs of keys are located on the keyboard, and how far apart they are. Then it would compare the results against a dictionary the researchers developed for this demonstration. The dictionary defines words based on their locations on a typical QWERTY keyboard, like left/right or near/far. So in Georgia Tech’s example, the word “canoe” would translate to c-a, a-n, n-o, o-e possibilities. That works out to left-left-near, and so on. The location code is checked against the dictionary, and it turns up “canoe” as the most likely word.

Related ArticlesA DIY UAV That Hacks Wi-Fi Networks, Cracks Passwords, and Poses as a Cell Phone TowerYour iPhone Keeps a Secret Log of Everywhere You Go, Security Experts FindLast Shuttle Mission Will Carry iPhones to the Space StationTagsTechnology, Rebecca Boyle, accelerometer, iphone, keystrokes, malware, smartphones, spying, spyware, typingUsing a dictionary of about 58,000 words, the researchers were able to decipher typing with about 80 percent accuracy.

Researchers have studied smartphone as spy-phone before, using the phones’ microphones to sample vibrations and decipher keystrokes. But they are very sensitive and so a much more obvious security risk — many smartphones now will ask users to give a new app permission to access sensors like microphones. Not accelerometers, however. So how would an app with this capability get onto your smartphone? The authors of this study say it would probably be included as malware on an innocent-seeming app. Then when the phone is placed next to a keyboard, the malware turns on and starts listening, sending data to a hacker who wants to know what you have to say.

Granted, this all works only if your phone is pretty proximate to your keyboard, admits Patrick Traynor, an assistant professor in Georgia Tech’s School of Computer Science who was involved in the study. So just keep it elsewhere on your desk or in your bag. Plus it’s unlikely that anyone has to worry about this right now, he added.

“This was really hard to do. But could people do it if they really wanted to? We think yes.”

The work is being presented Thursday at the ACM Conference on Computer and Communications Security in Chicago.

Previous Article: Wearable Projector and Kinect-Like Camera Turns Any Object Into a TouchscreenNext Article: Germany's ROSAT Satellite Could Come Crashing Down Somewhere On Earth As Soon As Friday 3 Comments Link to this comment Midoman 10/19/11 at 11:39 am

SuperPhones take Phreaking to a whole new level.

Link to this comment Q 10/19/11 at 12:42 pm

The CIA, FBI, others and other countries have been doing this for years, but with big large electronics. I suppose what is novel today it's now an App.

Besides Governmental offices locking down what type of cell phones can be brought into their areas, this also applies to civilian companies.

This will open the door to gaining access to logins and passwords, everywhere.

Just listen and record the clicks several days in a row. Will an average 80% copy quality; it should only take a few days of listening to find the login and password.

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October 2011: The Search for Alien Life

This month, we examine all the ways we're looking for extraterrestrial life, within our solar system and beyond.

Plus: Our annual Brilliant 10 list of young researchers, the story behind that "arsenic-based life form found" story, birth control for wildlife, and much more.

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NASA's Spitzer detects comet storm in nearby solar system

ScienceDaily (Oct. 19, 2011) — NASA's Spitzer Space Telescope has detected signs of icy bodies raining down in an alien solar system. The downpour resembles our own solar system several billion years ago during a period known as the "Late Heavy Bombardment," which may have brought water and other life-forming ingredients to Earth.

During this epoch, comets and other frosty objects that were flung from the outer solar system pummeled the inner planets. The barrage scarred our moon and produced large amounts of dust.

Now Spitzer has spotted a band of dust around a nearby bright star in the northern sky called Eta Corvi that strongly matches the contents of an obliterated giant comet. This dust is located close enough to Eta Corvi that Earth-like worlds could exist, suggesting a collision took place between a planet and one or more comets. The Eta Corvi system is approximately one billion years old, which researchers think is about the right age for such a hailstorm.

"We believe we have direct evidence for an ongoing Late Heavy Bombardment in the nearby star system Eta Corvi, occurring about the same time as in our solar system," said Carey Lisse, senior research scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., and lead author of a paper detailing the findings. The findings will be published in the Astrophysical Journal. Lisse presented the results at the Signposts of Planets meeting at NASA's Goddard Space Flight Center in Greenbelt, Md., on Oct. 19.

Astronomers used Spitzer's infrared detectors to analyze the light coming from the dust around Eta Corvi. Certain chemical fingerprints were observed, including water ice, organics and rock, which indicate a giant comet source.

The light signature emitted by the dust around Eta Corvi also resembles the Almahata Sitta meteorite, which fell to Earth in fragments across Sudan in 2008. The similarities between the meteorite and the object obliterated in Eta Corvi imply a common birthplace in their respective solar systems.

A second, more massive ring of colder dust located at the far edge of the Eta Corvi system seems like the proper environment for a reservoir of cometary bodies. This bright ring, discovered in 2005, looms at about 150 times the distance from Eta Corvi as Earth is from the sun. Our solar system has a similar region, known as the Kuiper Belt, where icy and rocky leftovers from planet formation linger. The new Spitzer data suggest that the Almahata Sitta meteorite may have originated in our own Kuiper Belt.

The Kuiper Belt was home to a vastly greater number of these frozen bodies, collectively dubbed Kuiper Belt objects. About 4 billion years ago, some 600 million years after our solar system formed, scientists think the Kuiper Belt was disturbed by a migration of the gas-giant planets Jupiter and Saturn. This jarring shift in the solar system's gravitational balance scattered the icy bodies in the Kuiper Belt, flinging the vast majority into interstellar space and producing cold dust in the belt. Some Kuiper Belt objects, however, were set on paths that crossed the orbits of the inner planets.

The resulting bombardment of comets lasted until 3.8 billion years ago. After comets impacted the side of the moon that faces Earth, magma seeped out of the lunar crust, eventually cooling into dark "seas," or maria. When viewed against the lighter surrounding areas of the lunar surface, those seas form the distinctive "Man in the Moon" visage. Comets also struck Earth or incinerated in the atmosphere, and are thought to have deposited water and carbon on our planet. This period of impacts might have helped life form by delivering its crucial ingredients.

"We think the Eta Corvi system should be studied in detail to learn more about the rain of impacting comets and other objects that may have started life on our own planet," Lisse said.

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

For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer .

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Nearby galaxy boasts two monster black holes, both active

ScienceDaily (June 11, 2011) — A study using NASA's Swift satellite and the Chandra X-ray Observatory has found a second supersized black hole at the heart of an unusual nearby galaxy already known to be sporting one.

The galaxy, which is known as Markarian 739 or NGC 3758, lies 425 million light-years away toward the constellation Leo. Only about 11,000 light-years separate the two cores, each of which contains a black hole gorging on infalling gas.

The study will appear in a forthcoming issue of The Astrophysical Journal Letters.

"At the hearts of most large galaxies, including our own Milky Way, lies a supermassive black hole weighing millions of times the sun's mass," said Michael Koss, the study's lead author at NASA's Goddard Space Flight Center in Greenbelt, Md., and the University of Maryland in College Park (UMCP). "Some of them radiate billions of times as much energy as the sun."

Astronomers refer to galaxy centers exhibiting such intense emission as active galactic nuclei (AGN). Yet as common as monster black holes are, only about one percent of them are currently powerful AGN. Binary AGN are rarer still: Markarian 739 is only the second identified within half a billion light-years.

Many scientists think that disruptive events like galaxy collisions trigger AGN to switch on by sending large amounts of gas toward the black hole. As the gas spirals inward, it becomes extremely hot and radiates huge amounts of energy.

Since 2004, the Burst Alert Telescope (BAT) aboard Swift has been mapping high-energy X-ray sources all around the sky. The survey is sensitive to AGN up to 650 million light-years away and has uncovered dozens of previously unrecognized systems. Follow-up studies by Koss and colleagues published in 2010 reveal that about a quarter of the Swift BAT AGN were either interacting or in close pairs, with perhaps 60 percent of them poised to merge in another billion years.

"If two galaxies collide and each possesses a supermassive black hole, there should be times when both black holes switch on as AGN," said coauthor Richard Mushotzky, professor of astronomy at UMCP. "We weren't seeing many double AGN, so we turned to Chandra for help."

Swift's BAT instrument is scanning one-tenth of the sky at any given moment, its X-ray survey growing more sensitive every year as its exposure increases. Where Swift's BAT provided a wide-angle view, the X-ray telescope aboard the Chandra X-ray Observatory acted like a zoom lens and resolved details a hundred times smaller.

For decades, astronomers have known that the eastern nucleus of Markarian 739 contains a black hole that is actively accreting matter and generating prodigious energy. The Chandra study shows that its western neighbor is too. This makes the galaxy one of the nearest and clearest cases of a binary AGN.

The distance separating the two black holes is about a third of the distance separating the solar system from the center of our own galaxy. The dual AGN of Markarian 739 is the second-closest known, both in terms of distance from one another and distance from Earth. However, another galaxy known as NGC 6240 holds both records.

How did the second AGN remain hidden for so long? "Markarian 739 West shows no evidence of being an AGN in visible, ultraviolet and radio observations," said coauthor Sylvain Veilleux, a professor of astronomy at UMCP. "This highlights the critical importance of high-resolution observations at high X-ray energies in locating binary AGN."

The research team also includes Ezequiel Treister and David Sanders at the University of Hawaii's Institute for Astronomy in Honolulu, Kevin Schawinski at Yale University in New Haven, Conn., and Ranjan Vasudevan, Neal Miller and Margaret Trippe at the University of Maryland, College Park.

Swift, launched in November 2004, is managed by Goddard. It was built and is being operated in collaboration with Penn State University, the Los Alamos National Laboratory in New Mexico, and General Dynamics in Falls Church, Va.; the University of Leicester and Mullard Space Sciences Laboratory in the United Kingdom; Brera Observatory and the Italian Space Agency in Italy; plus additional partners in Germany and Japan.

The Marshall Space Flight Center manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

For more information, images and video, please visit: http://www.nasa.gov/mission_pages/swift/bursts/monster-black-holes.html

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by NASA/Goddard Space Flight Center.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Nearby galaxy boasts two monster black holes, both active

ScienceDaily (June 11, 2011) — A study using NASA's Swift satellite and the Chandra X-ray Observatory has found a second supersized black hole at the heart of an unusual nearby galaxy already known to be sporting one.

The galaxy, which is known as Markarian 739 or NGC 3758, lies 425 million light-years away toward the constellation Leo. Only about 11,000 light-years separate the two cores, each of which contains a black hole gorging on infalling gas.

The study will appear in a forthcoming issue of The Astrophysical Journal Letters.

"At the hearts of most large galaxies, including our own Milky Way, lies a supermassive black hole weighing millions of times the sun's mass," said Michael Koss, the study's lead author at NASA's Goddard Space Flight Center in Greenbelt, Md., and the University of Maryland in College Park (UMCP). "Some of them radiate billions of times as much energy as the sun."

Astronomers refer to galaxy centers exhibiting such intense emission as active galactic nuclei (AGN). Yet as common as monster black holes are, only about one percent of them are currently powerful AGN. Binary AGN are rarer still: Markarian 739 is only the second identified within half a billion light-years.

Many scientists think that disruptive events like galaxy collisions trigger AGN to switch on by sending large amounts of gas toward the black hole. As the gas spirals inward, it becomes extremely hot and radiates huge amounts of energy.

Since 2004, the Burst Alert Telescope (BAT) aboard Swift has been mapping high-energy X-ray sources all around the sky. The survey is sensitive to AGN up to 650 million light-years away and has uncovered dozens of previously unrecognized systems. Follow-up studies by Koss and colleagues published in 2010 reveal that about a quarter of the Swift BAT AGN were either interacting or in close pairs, with perhaps 60 percent of them poised to merge in another billion years.

"If two galaxies collide and each possesses a supermassive black hole, there should be times when both black holes switch on as AGN," said coauthor Richard Mushotzky, professor of astronomy at UMCP. "We weren't seeing many double AGN, so we turned to Chandra for help."

Swift's BAT instrument is scanning one-tenth of the sky at any given moment, its X-ray survey growing more sensitive every year as its exposure increases. Where Swift's BAT provided a wide-angle view, the X-ray telescope aboard the Chandra X-ray Observatory acted like a zoom lens and resolved details a hundred times smaller.

For decades, astronomers have known that the eastern nucleus of Markarian 739 contains a black hole that is actively accreting matter and generating prodigious energy. The Chandra study shows that its western neighbor is too. This makes the galaxy one of the nearest and clearest cases of a binary AGN.

The distance separating the two black holes is about a third of the distance separating the solar system from the center of our own galaxy. The dual AGN of Markarian 739 is the second-closest known, both in terms of distance from one another and distance from Earth. However, another galaxy known as NGC 6240 holds both records.

How did the second AGN remain hidden for so long? "Markarian 739 West shows no evidence of being an AGN in visible, ultraviolet and radio observations," said coauthor Sylvain Veilleux, a professor of astronomy at UMCP. "This highlights the critical importance of high-resolution observations at high X-ray energies in locating binary AGN."

The research team also includes Ezequiel Treister and David Sanders at the University of Hawaii's Institute for Astronomy in Honolulu, Kevin Schawinski at Yale University in New Haven, Conn., and Ranjan Vasudevan, Neal Miller and Margaret Trippe at the University of Maryland, College Park.

Swift, launched in November 2004, is managed by Goddard. It was built and is being operated in collaboration with Penn State University, the Los Alamos National Laboratory in New Mexico, and General Dynamics in Falls Church, Va.; the University of Leicester and Mullard Space Sciences Laboratory in the United Kingdom; Brera Observatory and the Italian Space Agency in Italy; plus additional partners in Germany and Japan.

The Marshall Space Flight Center manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

For more information, images and video, please visit: http://www.nasa.gov/mission_pages/swift/bursts/monster-black-holes.html

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by NASA/Goddard Space Flight Center.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Spitzer detects shadow of 'super-Earth' in front of nearby star

ScienceDaily (May 5, 2011) — NASA's Spitzer Space Telescope has detected the crossing of a solid planet  in front of a star located at only 42 light-years in the constellation Cancer. Thanks to this detection, astronomers know that this "super-Earth" measures 2.1 times the size of our Earth. This is the smallest exoplanet detected in the neighborhood of our Sun.

The discovery is based on data acquired by the Spitzer spacecraft last January. The data allowed astronomers to detect the "transit" of the planet, i.e. the tiny decrease of the star's brightness occurring when the planet passes in front of it.

"So far, the exquisite capabilities of Spitzer have been extensively used to study known transiting exoplanets, all of them being giant planets similar to Jupiter or Neptune. For the first time, Spitzer is used to detect the transit of a super-Earth, a solid planet not much larger than our own Earth," says Michaël Gillon from University of Liège (Belgium), the leader of the team that made this detection. "Thanks to the high-precision of Spitzer, we now know the nature of this planet, and, interestingly, it is very different from all the planets of our solar System."

The planet name is 55 Cancri e. With 8 times the mass of the Earth, for a size 2.1 larger, it is simply too big to be purely rocky, meaning that it must have a significant fraction of ice, the favored composition being a massive shell of water ice on top of a rocky nucleus. "We could call this planet a 'naked Neptune', as it is very similar to Neptune except that it has no gazeous envelope of hydrogen above its ice shell," says Brice-Olivier Demory from the Massachusets Institute of Technology (MIT), the first author of the paper describing the discovery. "But the analogy with Neptune stops here: 55 Cancri e is more than 1900 times closer to its star than Neptune to the Sun. At such a short distance, the planet is literally baked by the intense stellar radiation."

The host star itself  has a particularity that makes this planet very interesting for astronomers. It is not a dim star that can only be seen with a telescope, but a very bright star of the solar neighborhood (42 light-years), visible even for the human eye. "The brightness of the host star will make possible the first throrough characterization of a solid planet orbiting a star similar to our Sun," says Gillon. "If this planet has an atmosphere, we will be able to study it details, unlike the other solid planets found  so far around farer and dimmer stars."

Interestingly, the study of the atmosphere of 55 Cancri e has maybe already begun. Indeed, another team of astronomers indepently announced April 29, the detection of the transits of the same planet with another space telescope, MOST. This team observed at a different wavelength than Spitzer, and their measured planet radius is 1.3 times smaller. "A possible explanation for this discrepancy would be the presence of a huge molecular enveloppe outgassed by the planet, making the planet appear larger for Spitzer," says Demory. "Only new measurements will tell us."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Liège.

Journal References:

B.-O. Demory, M. Gillon, D. Deming, D. Valencia, S. Seager, B. Benneke, C. Lovis, P. Cubillos, J. Harrington, K. B. Stevenson, M. Mayor, F. Pepe, D. Queloz, D. Segransan, S. Udry. Detection of a transit of the super-Earth 55 Cnc e with Warm Spitzer. Astronomy & Astrophysics, 2011; (submitted) [link]Joshua N. Winn, Jaymie M. Matthews, Rebekah I. Dawson, Daniel Fabrycky, Matthew J. Holman, Thomas Kallinger, Rainer Kuschnig, Dimitar Sasselov, Diana Dragomir, David B. Guenther, Anthony F.J. Moffat, Jason F. Rowe, Slavek Rucinski, Werner W. Weiss. A Super-Earth Transiting a Naked-Eye Star. Astrophysical Journal Letters, 2011; (submitted) [link]

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Spitzer detects shadow of 'super-Earth' in front of nearby star

ScienceDaily (May 5, 2011) — NASA's Spitzer Space Telescope has detected the crossing of a solid planet  in front of a star located at only 42 light-years in the constellation Cancer. Thanks to this detection, astronomers know that this "super-Earth" measures 2.1 times the size of our Earth. This is the smallest exoplanet detected in the neighborhood of our Sun.

The discovery is based on data acquired by the Spitzer spacecraft last January. The data allowed astronomers to detect the "transit" of the planet, i.e. the tiny decrease of the star's brightness occurring when the planet passes in front of it.

"So far, the exquisite capabilities of Spitzer have been extensively used to study known transiting exoplanets, all of them being giant planets similar to Jupiter or Neptune. For the first time, Spitzer is used to detect the transit of a super-Earth, a solid planet not much larger than our own Earth," says Michaël Gillon from University of Liège (Belgium), the leader of the team that made this detection. "Thanks to the high-precision of Spitzer, we now know the nature of this planet, and, interestingly, it is very different from all the planets of our solar System."

The planet name is 55 Cancri e. With 8 times the mass of the Earth, for a size 2.1 larger, it is simply too big to be purely rocky, meaning that it must have a significant fraction of ice, the favored composition being a massive shell of water ice on top of a rocky nucleus. "We could call this planet a 'naked Neptune', as it is very similar to Neptune except that it has no gazeous envelope of hydrogen above its ice shell," says Brice-Olivier Demory from the Massachusets Institute of Technology (MIT), the first author of the paper describing the discovery. "But the analogy with Neptune stops here: 55 Cancri e is more than 1900 times closer to its star than Neptune to the Sun. At such a short distance, the planet is literally baked by the intense stellar radiation."

The host star itself  has a particularity that makes this planet very interesting for astronomers. It is not a dim star that can only be seen with a telescope, but a very bright star of the solar neighborhood (42 light-years), visible even for the human eye. "The brightness of the host star will make possible the first throrough characterization of a solid planet orbiting a star similar to our Sun," says Gillon. "If this planet has an atmosphere, we will be able to study it details, unlike the other solid planets found  so far around farer and dimmer stars."

Interestingly, the study of the atmosphere of 55 Cancri e has maybe already begun. Indeed, another team of astronomers indepently announced April 29, the detection of the transits of the same planet with another space telescope, MOST. This team observed at a different wavelength than Spitzer, and their measured planet radius is 1.3 times smaller. "A possible explanation for this discrepancy would be the presence of a huge molecular enveloppe outgassed by the planet, making the planet appear larger for Spitzer," says Demory. "Only new measurements will tell us."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Liège.

Journal References:

B.-O. Demory, M. Gillon, D. Deming, D. Valencia, S. Seager, B. Benneke, C. Lovis, P. Cubillos, J. Harrington, K. B. Stevenson, M. Mayor, F. Pepe, D. Queloz, D. Segransan, S. Udry. Detection of a transit of the super-Earth 55 Cnc e with Warm Spitzer. Astronomy & Astrophysics, 2011; (submitted) [link]Joshua N. Winn, Jaymie M. Matthews, Rebekah I. Dawson, Daniel Fabrycky, Matthew J. Holman, Thomas Kallinger, Rainer Kuschnig, Dimitar Sasselov, Diana Dragomir, David B. Guenther, Anthony F.J. Moffat, Jason F. Rowe, Slavek Rucinski, Werner W. Weiss. A Super-Earth Transiting a Naked-Eye Star. Astrophysical Journal Letters, 2011; (submitted) [link]

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here