Big ideas from the smallest world Feb 1, 2008
A: Snowflakes are crystals that grow by accretion of water vapor from the air, and the details depend on how the crystal boundary interacts with the cloud of water vapor. There is a feedback effect that promotes branching and the formation of dendrites [arms]: If some part of the surface is more exposed to the cloud, that accentuates its ability to attract more stuff, so as it becomes further out, it gets easier for the diffusing particles to find this part of the surface. (Why Files)
Supernova Surprise: Black Holes May Pull Apart, Reignite White Dwarf Stars Feb 1, 2008
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 ... While the ejected matter expands rapidly, the infalling matter builds a violent, thick accretion disk around the black hole. (Science Daily)
Black holes spin near the speed of light Jan 16, 2008
Researchers previously found that the greater the amount of gas falling into supermassive black holes known as the accretion rate the greater the energy of the jets shooting out ... The observed jet power and accretion rates were huge one black hole ate 10 Earth masses per month and, from its surroundings, spat out 50 times the annual energy of our sun per second. (MSNBC -- Technology)
Light Echo Show From Black Hole Predicted Jan 11, 2008
This artist rendition shows an accretion disk swirling around a black hole. The two hot spots could give off powerful X-ray flares. (Science Daily)
Rapidly Whirling Black Holes Revealed Jan 11, 2008
Computer simulations by other authors have suggested that black holes may acquire their rapid spins when galaxies merge, and through the accretion of gas from their surroundings. "Extremely fast spin might be very common for large black holes," said co-investigator Richard Bower of Durham University. (Science Daily)
Planets form twice for old stars Jan 10, 2008
These include the active, rapid accretion of gas, an extended orbiting disc of dust and gas, excess emission in the infrared spectrum and - in the case of BP Piscium - jets of gas being fired off into space. After star formation, the dust and gas left over gradually forms planetesimals, like comets and asteroids, as well as planets. (BBC News -- Science)
10,000 Earths' Worth Of Fresh Dust Found Near Star Explosion Dec 22, 2007
7, 2007) A team of European astronomers offer new evidence that high-mass stars could form in a similar way to low-mass stars, that is, from accretion of gas and dust through a disk surrounding the forming. (May 18, 1998) In a paper published in the May 14 issue of Nature, Alan Boss of the Carnegie Institution of Washington explains that by looking for wobbles in young stars, a clear-cut test can be applied that will. (Science Daily)
Neptune and Uranus traded cosmic places Dec 19, 2007
While Desch cautioned other theorists may find the updated model difficult to swallow, he explained that it's compatible with either of two competing theories of gas giant formation: a or an accretion of it around a rocky core. "Whatever the case, nobody's ever been able to explain how to form Neptune and Uranus within the window of 10 million years," he said. (MSNBC -- Technology)
New findings explain Saturn's flying-saucer moons Dec 8, 2007
These findings could shed light on the behavior of "accretion disks" disks that build up as matter falls toward a gravitational pull. Understanding how the icy particles piled up to make these shapes could explain how matter in the protoplanetary disk that accreted around our newborn sun could have clumped together to make planets, Charnoz added. (Xinhuanet, China)
Flying saucers around Saturn explained Dec 7, 2007
These findings could shed light on the behavior of "accretion disks" disks that build up as matter falls toward a gravitational pull. "Accretion disks are found everywhere in the universe , around stars, around Jupiter," said astrophysicist Sebastien Charnoz at University of Paris Diderot in France. (MSNBC -- Technology)
New views show Mars was once red hot Nov 28, 2007
"The primitive atmosphere was composed mostly of hydrogen left over from accretion into a rocky planet," Debaille said. "But [it] was removed, probably by impacts, about 100 million years after the planet formed.". (MSNBC -- Technology)
Earth was molten before formation Nov 26, 2007
The primitive atmosphere was composed mostly of hydrogen left over from accretion into a rocky planet, but was removed, probably by impacts, about 100 million years after the planet formed, said another researcher. In fact, they performed precise measurements of neodymium isotope compositions of nine rare Martian meteorites called shergottites using mass spectrometers at JSC and UCD before coming to the conclusion. (India Times, India -- Health/Science)
New Light On Early Formation Of Earth And Mars Nov 25, 2007
The primitive atmosphere was composed mostly of hydrogen left over from accretion into a rocky planet, but was removed, probably by impacts, about 100 million years after the planet formed, said Debaille ... Debaille and her colleagues found that the scenario that best fits the data is one where a global-scale magma ocean formed from melting in Mars during the final stages of accretion and then slowly solidified over this time period. (Science Daily)
Another Way That Stars May Evolve Nov 22, 2007
7, 2007) A team of European astronomers offer new evidence that high-mass stars could form in a similar way to low-mass stars, that is, from accretion of gas and dust through a disk surrounding the forming. (Feb. (Science Daily)
Black holes suck stuff in, blow it away Nov 8, 2007
Astronomers have long thought that such "accretion disks" give off mighty winds that shape the host galaxies, profoundly influencing how they grow ... Scientists had only theorized that accretion disks launched these winds ... "These accretion disks are comparable in size to our solar system -- big for us, but on the scale of galaxies they're really tiny, and far away to boot, making it virtually impossible to distinguish any details such as winds," Robinson said. (Xinhuanet, China)
Supermassive Black Holes Produce Powerful Galaxy-shaping Winds Nov 2, 2007
The RIT team has, for the first time, observed the vertical launch of rotating winds from glowing disks of gas, known as accretion disks, surrounding supermassive black holes in the centers of galaxies. Gas flowing into a supermassive black hole first accumulates in a rapidly spinning accretion disk, which forms the engine of a quasar, a type of active galactic nucleus found in some galaxies and an extremely powerful source of radiation ... It has long been thought that such winds are launched... (Science Daily)
Hubble spies shells of sparkling stars around quasar Oct 26, 2007
The accretion onto the black hole is the quasars energy-source. This observation supports the idea that some quasars are born from interactions between galaxies, said Canalizo, an assistant professor of astrophysics in the , and a member of the. (EurekAlert!)
Shouldn't Be Possible Oct 20, 2007
An artist's representation of M33 X-7, where a massive blue star feeds material to a black hole surrounded by a small accretion disk. A stellar black hole much more massive than theory predicts is possible has astronomers puzzled. (Fox News)
Monster black hole busts theory Oct 18, 2007
An artist's representation of M33 X-7: a binary system in the nearby galaxy M33, containing a massive blue star feeding material to a black hole surrounded by a small accretion disk. . (MSNBC -- Technology)
Scientists shave 15 minutes off Saturn's day Sep 7, 2007
According to the "core accretion" model, gas giants form in a similar manner to rocky planets, by gradually accreting rocky debris until they become so large that they draw vast quantities of hydrogen and helium gas unto themselves. In the competing "" model, gas planets form when large clumps of gas orbiting in debris disks around young stars collapse under their own gravity to eventually form planets. (MSNBC -- Technology)
New Method for Probing Exotic Matter Aug 29, 2007
Besides using these iron lines to test Einsteins general theory of relativity, astronomers can probe conditions in the inner part of a neutron stars accretion disk. The XMM-Newton paper appeared in the August 1 Astrophysical Journal Letters. (SkyAndTelescope.com)
Space-time Distorts Near Neutron Stars As Einstein Predicted Aug 29, 2007
Besides using these iron lines to test Einstein s general theory of relativity, astronomers can probe conditions in the inner part of a neutron star s accretion disk. The XMM-Newton paper appeared in the August 1 Astrophysical Journal Letters. (Science Daily)
Neutron stars warp space-time, U-M astronomers observe Aug 29, 2007
Besides using these iron lines to test Einstein's general theory of relativity, astronomers can probe conditions in the inner part of a neutron star's accretion disk. "Now that we've seen this relativistic iron line around three neutron stars, we have established a new technique," Miller said. (EurekAlert!)
Will Titan Lose Its Veil? Aug 28, 2007
Dr Dimitrov said, The conditions of Titan s accretion and evolution are poorly understood, so we cannot yet say how many of the cages were filled and how much methane is contained in the reserve. In addition, we need to do some more experiments in the laboratory to find out more about the transfer of materials between layers. (Science Daily)
WorldWater & Solar Technologies Announces Second Quarter Results Aug 14, 2007
9% Operating Expenses: Marketing, general and administrative expenses $ 3,005,812 $ 1,704,251 $ 5,305,434 $ 3,654,815 Research and development expense $ 70,023 $ 62,548 $ 117,501 $ 151,281 ------------ ------------ ------------ ------------ Total Expenses 3,075,835 1,766,799 5,422,935 3,806,096 ------------ ------------ ------------ ------------ Loss from Operations (2,738,570) (1,489,666) (4,886,279) (3,398,049) ------------ ------------ ------------ ------------ Other (Expense) Income Debt... (Primezone Releases)
Giant planets usually snuggle up to their suns Jul 18, 2007
The two leading theories about how planets form-core accretion and disk instability-have problems making gas giants out at distances beyond 20 AU. "There just isn't enough disk mass out there unless the disk is implausibly massive," Boss told SPACE.com. "Any planets formed out at those distances are probably the result of orbital interactions between unstable systems, and unstable systems are expected to form rarely, if at all," Boss added. (MSNBC -- Technology)
Astronomers Get Better View Of Density Waves In Galaxies Jul 13, 2007
These early secular evolution proposals, however, stressed mostly the accretion of the gas component, and thus were limited to the evolution of the more-flattened types of galaxies which have smaller bulges, since the bulk of a galaxy's luminous mass, in particular its bulge mass, is made of stars ... A new dynamical mechanism that allows the secular exchange of energy and angular momentum between the disk matter and the density wave is found to underlie both the stellar and gaseous accretion... (Science Daily)
Significant new method developed for characterizing density wave features Jul 10, 2007
Zhang and Buta have also confirmed that a previously proposed internal physical process termed "secular dynamical evolution, which is driven by these density waves, can transform the shapes of galaxies over their lifetime. This provides an important link to our understanding of how galaxies in the universe were formed and how they evolve. Observed galaxies can be roughly grouped into two kinds: highly flattened disk-shaped galaxies, such as the Milky Way, and ellipsoidal galaxies. More... (EurekAlert!)
Neutron Star Has Monster X-Ray Jet Jul 1, 2007
"Jets are these mysterious beams of matter. These are plasma beams that get launched in the inner regions of accretion flows," explains Heinz. Finding a neutron star powering a massive jet instead of a black hole has brought the realization that "gravity appears to be the key to creating these jets, not some trick of the event horizon." A startlingly high percentage of the energy that comes from the infalling matter must be used to power the jet. (Suite101.com)
NYC's First Solar-Powered Oyster Reef - Art Meets Science Jun 30, 2007
The project will employ a mineral accretion process known as Biorock, which uses low voltage, direct-current electricity to grow solid limestone underwater. The electrical current causes minerals that are naturally dissolved in seawater to precipitate and adhere to a metal structure, and the resulting limestone has a strength similar to that of concrete. (Yahoo News -- Press Releases)
Computer Models Suggest Planetary And Extrasolar Planet Atmospheres Jun 22, 2007
"The theory about the Gas Giant planets (Jupiter, Saturn, Uranus, and Neptune) is that they have primary atmospheres, which means that their atmospheres were captured directly from the solar nebula during accretion of the planets," Fegley said. Gas Giants. (Science Daily)
Why Monster Black Holes Don't Run Away Jun 13, 2007
The black holes orbit each other within this disk, and each monster draws gas from the disk to form a smaller accretion disk. These much smaller disks will torque the spin axes of the two black holes, causing both their axes to realign perpendicular to the orbital plane. (SkyAndTelescope.com)
The Loneliest Black Holes In The Universe Jun 6, 2007
The researchers also found that the accretion of matter onto these void black holes is slower than in denser galactic environments ... Constantin adds that, the more isolated accreting black holes are however not as active as the ones in more populous environs, and the fuel seems less available for accretion in voids than in urban galaxies ... The smaller accretion rate observed in void galaxies means that this gas is just not getting down to the nuclear region where accretion happens. (Science Daily)
Two new planets lack heavy foundations Jun 6, 2007
The alternative to this 'core accretion' model is a process in which the disk itself breaks up into clumps that gradually collapse into planets ... Core accretion is generally the favoured theory for the formation of the small, Earth-like planets in our own Solar System, but some researchers think that disk instability might account for our gas-giant neighbours, such as Jupiter ... "I think these two new planets present a major challenge for the core-accretion model.". (Nature News Service)
Physicist Says Testing Technique For Gravitomagnetic Field Is Ineffective Jun 3, 2007
"If the existence of the gravitomagnetic field is confirmed, then our understanding of general relativity is correct and can be used to explain things such as quasar jets and accretion disks in black holes," said Sergei Kopeikin, associate professor of physics in MU's College of Arts and Science. "General relativity explains the origin of the universe, and that's important for all humankind, irrespective of religion or creed. We all live in the same world, and we must understand this place in... (Science Daily)
XMM-Newton Deciphers The Magnetic Physics Around Forming Stars Jun 2, 2007
The sensitive spectroscopy of the Taurus project has provided clear confirmation that those stars onto which gas streams are still falling from their gaseous surroundings emit less X-rays than stars in which these accretion processes have ceased ... The cool accretion streams originate in gas disks orbiting the star ... These jets in turn generate X-rays that heat the disk and further enhance accretion. (Science Daily)
XMM-Newton Reveals X-rays From Gas Streams Around Young Stars Jun 2, 2007
Most of these stars are still accumulating matter, a process known as accretion ... "This emission must come from outside the accretion streams," says Guedel. (Science Daily)
Loner black holes lurk in cosmic voids Jun 2, 2007
In crowded galactic regions, they identified more supermassive black holes at later stages in their evolutionary process, suggesting "cities" are conducive for faster accretion rates ... "The void galaxy black holes might take longer to reach the mature, low accretion rate phase, which might explain why the most massive, lazy black holes are less frequent in voids," Constantin said ... So perhaps interactions between galaxies could explain the different accretion rates, the scientists said. (MSNBC -- Technology)
'Seat belts' restrain galaxies' black holes May 31, 2007
A giant disc of gas forms around the still-separate black holes, roughly in the same plane as their orbit, and each black hole draws matter from this giant disc into a small "accretion disc" aligned with the holes equator. The accretion disc acts like a handle on the hole ... Over a million years or so the gravity of the larger disc pulls each accretion disc into line, and along with it the spinning black hole. (New Scientist (subscription))
How To Spot The Speediest Black Holes May 31, 2007
Some doubted that the quarry could be spotted, since a black hole must be gobbling matter from an accretion disk in order for that matter to shine. And if a black hole is ripped from the core of its home galaxy and sent hurling into the outskirts, the thinking goes, then its accretion disk might be left behind ... Loeb showed that, generically, a black hole ejected from the center of a galaxy could bring its accretion disk along for the ride and remain visible for millions of years. (Science Daily)
Astronomers Discover 28 New Exoplanets And Four Multi-Planet Systems May 30, 2007
As would be expected from the core accretion model of planet formation, large planets are more often observed around massive stars, probably because these stars start out with more material in their disks during the early formation period. Johnson will continue to focus on retired A stars, 450 of which have been added to the teams' target list. (Science Daily)
Mystery of runaway black holes solved May 30, 2007
The black hole drags part of its surrounding accretion disk along for the ride ... The group's research built upon the findings from , in which scientists concluded that a runaway black hole can carry its accretion disk on its journey as long as the disk spins around the black hole faster than the black hole's ejection speed ... "We were looking for signs that the kicked black hole was carrying its accretion disk with it," Bonning said. (MSNBC -- Technology)
'Failed star' spews jets from its poles May 29, 2007
"It seems like almost any time you have accretion disk around an object, some of the material that's accreted is also spewed out," Jayawardhana said. Both Saturn and Jupiter are thought to have grown out of accretion disks. (MSNBC -- Technology)
USGS Has Science That Weathers the Storm May 26, 2007
Hurricane Research Scientific research at the USGS related to hurricanes includes: 1) radar- tracking of migratory birds during the fall migration period to assess possible effects of hurricanes on migration patterns; 2) studying global climate change and effects of sea-level rise on coastal wetlands and forests; 3) predicting the persistence of coastal wetlands to global climate change effects, including effects of altered temperature and atmospheric carbon dioxide; 4) biogenic accretion... (PR Newswire)
> read more May 23, 2007
Gas from the blue supergiant star orbits the black hole in an accretion disk ... This transferred gas rotates around the black hole in an accretion disk, emitting X-rays as it becomes energized and occasionally clumping together in what Titarchuk refers to as a "traffic jam." He finds that the farther these clumps form from the black hole, the more massive it is ... One uses the black hole's energy output to estimate its mass (the more luminous it is, the more massive), and the other uses the... (SkyAndTelescope.com)
Astrophysicists try to weigh a black hole May 22, 2007
Instead of using gravity, astronomers examine the spinning disk of hot gases that gobble up from neighboring stars-also called the accretion disk ... Once that's done, he said, the weight of newly-discovered black holes may quickly be discovered by examining the QPO of their accretion disks. (MSNBC -- Technology)
NASA Scientists Pioneer Technique For 'Weighing' Black Holes May 17, 2007
Titarchuk s method takes advantage of a relationship between a black hole and the surrounding disk of matter spiraling into it, called an accretion disk ... When a black hole s accretion rate increases to a high level, material piles up near the black hole in a hot region that Titarchuk likens to a traffic jam ... The QPOs are accompanied by simple, predictable changes in the system s spectrum as the surrounding gas heats and cools in response to the changing accretion rate. (Science Daily)
Energy diplomacy with attitude Apr 18, 2007
So too, reducing China's fear of being left alone in the cold may reduce its accretion of influence in Africa and Latin America through aggressive purchases of oil assets there. Second, if four of the world's most technologically innovative countries sit down together, it could prompt a broader, deeper dialogue about both technology gains and conservation. (Asia Times Online)
Black hole caught in an eclipse Apr 13, 2007
Scientists think the supermassive , also called an active galactic nucleus, or AGN, is fed by a steady stream of material swirling around it in the form of a so-called accretion disk ... Even more challenging, the accretion disk of NGC 1365 is too small for astronomers to resolve directly with a telescope ... During five of the observations, high energy X-rays generated by swirling material in the accretion disk was visible. (MSNBC -- Technology)
Magnetic Fields Get Reconnected In Turbulent Plasma Too, Cluster Reveals Mar 29, 2007
One of the most turbulent environments in the near-Earth space, the terrestrial magnetosheath is an accessible laboratory to study in-situ turbulence, unlike the solar atmosphere or accretion disks. Characterising the properties of the magnetic turbulence in this region is of prime importance to understand its role in fundamental processes such as energy dissipation and particle acceleration. (Science Daily)
Hughes Communications, Inc. Announces Fourth Quarter and Full Year 2006 Results Mar 27, 2007
01 par value; no shares authorized, issued or outstanding as of December 31, 2006; 50,000,000 shares authorized, and 4,495,106 shares issued and outstanding as of December 31, 2005 45 Additional paid in capital 626,927 473,737 Accumulated deficit (410,408) (371,295) Accumulated other comprehensive loss (1,149) (4,106) Total stockholders' equity 215,389 98,385 Total liabilities and stockholders' equity $931,644 $205,337 HUGHES COMMUNICATIONS, INC. Consolidated Statements of Operations (Dollars in... (PR Newswire)
Shrivastava: Development in India Mar 12, 2007
Only the ecological future global and local climate change, to name only one of dozens of environmental ailments brought on by mindless industrialization will reveal the ultimately suicidal nature of this putatively free market economics which is in fact a case of active promotion of private corporate profit by the state, even if it means rampant exploitation of the poor citizens (who are citizens for one day and subjects for 5 years) of a famous democracy, in addition to the... (Zmag.org)
Jet Of Molecular Hydrogen Arising From A Forming High-mass Star Mar 8, 2007
A team of European astronomers offer new evidence that high-mass stars could form in a similar way to low-mass stars, that is, from accretion of gas and dust through a disk surrounding the forming star ... This detection confirms the hypothesis based on their earlier discovery that this forming high-mass star is surrounded by a large accretion disk ... Recent astronomical observations suggest that high-mass stars could form through accretion processes, just like low-mass stars do. (Science Daily)
Black holes shed light on galaxy formation Feb 21, 2007
This started locally with the discovery of the very close correlations between the masses of black holes and the properties of their host galaxies, and then moved on to the realization that galaxy formation and had to be partly controlled by the effects of black holes and accretion, said Christopher Kochanek of Ohio State University. While scientists have yet to observe a black hole directly, they have spotted X-ray radiation created by friction near the , the perimeter around a black hole... (MSNBC -- Technology)
Some light on black holes Feb 21, 2007
"This started locally with the discovery of the very close correlations between the masses of black holes and the properties of their host galaxies, and then moved on to the realization that galaxy formation and star formation had to be partly controlled by the effects of black holes and accretion," said Christopher Kochanek of Ohio State University. Black hole spin. (USA Today -- Tech)
The give and take of black holes Jan 9, 2007
The wind seen coming from the central region of the active galaxies studied by orbiting observatories appears to originate from the disc of matter orbiting the black hole, called the accretion disc, once thought to consist of material destined only to fall into the black hole. Researchers now suggest that a wind - created by the pressure of radiation - could blow away material from an accretion disc and seed interstellar space with heavier elements out of which stars could form with the right... (BBC News -- Science)
Computer Scientists Discover New Way To Spin Up Pulsars Jan 8, 2007
The darkest portion of the accretion shock denotes the front edge of the wave as it rotates around the supernova's center. Three-dimensional computer models are the only models that show this effect. (Science Daily)
