The technology industry’s newest high-powered political lobby, FWD.us, is unraveling just a month after it launched, as two of its biggest partners, Tesla’s Elon Musk and Yammer’s David Sacks, leave the organization. Begun with a reported $20 million of Mark Zuckerberg’s own money, and rare op-ed by the politically shy Facebook founder, FWD.us has faced a torrent of criticism over funding advertisements that praise Republicans who support the controversial Keystone pipeline (below). Environmental groups were up in arms and circulated a boycott of FWD.us that had, ironically, had more supporters than FWD.us’s call to action. The Sierra Club, Progressives United and MoveOn.org were among a littany of progressive groups that are now boycotting Facebook?advertisements.? ?Immigration reform ? fine. Oil expansion and pipelines? NOT fine. Where?s the transparency here, rich dudes? Or does FWD actually stand for Fine With Drilling?,? wrote one angry commenter on the FWD.us Facebook page. Elon Musk, as founder of Tesla Motors, prides himself on a sterling environmental record, so it’s easy to see why he couldn’t tolerate being associated with a group indirectly funding pro-Keystone pipeline ads. But, David Sacks doesn’t have as much to lose publically as Musk, which means that Musk is likely hooking more high-level partners with his departure. Nor is this the group’s first PR disaster. Even before the group began, FWD.us director and Zuckerberg’s old Harvard roommate, Joe Green, had to issue a statement of regret for a leaked perspectus. “Given the status of our funders and quality of our team, we will drive national and local narratives to properly frame our agenda,” read the brash strategy note. As we’ve written about before, FWD.us has kept a tight lid on their funding and tactics. We do know that FWD.us splits its organization into Democratic and Republican teams, offering quid pro quo cash in exchange for support of its key initiative — immigration. This kind of back-door compromising may work in D.C., but it’s evidently not as well tolerated in the Valley. In my own off-the-record conversations with supporters, no one is happy with FWD.us right now. It’s going to become a political landmine to stay on board, let alone join the group. FWD.us is unraveling, and we predict it won’t be around much longer unless it becomes a lot more transparent and ditches the D.C. tactics. Stay tuned for more.
May 9, 2013 ? In a joint project between the Universities of Strathclyde and Glasgow, Imperial College London and the National Physical Laboratory, researchers have developed a portable way to produce ultracold atoms for quantum technology and quantum information processing.
Their research has been published in the journal Nature Nanotechnology.
Many of the most accurate measurement devices, including atomic clocks, work by observing how atoms transfer between individual quantum states. The highest precision is obtained with long observation times, often using slow-moving ultracold atoms prepared in a large apparatus.
Dr Aidan Arnold, a Lecturer in Strathclyde's Department of Physics, said: "The longer the transition of atoms can be observed, the more precisely they can be measured. It is possible to shine laser light on atoms to slow them down using the Doppler effect. We can now do this in a really small device."
The researchers have developed technology which is far more compact than previous setups but can still cool and trap large numbers of atoms for use in portable devices. They pattern the surface of a semiconductor chip to form a diffraction grating, splitting a laser into many beams that cool the atoms.
Professor Ed Hinds, who directs the Centre for Cold Matter at Imperial College London, said: "These specially micro-fabricated diffraction gratings create the perfect laser beams for trapping and cooling atoms."
Portable clocks, magnetometers and accelerometers have wide-ranging applications, including navigation on earth and in space, telecomunications, geological exploration, and medical imaging.
Dr Alastair Sinclair, Principal Scientist at the National Physical Laboratory, said: "The miniaturisation of atomic sensors using these optical gratings can make an important contribution to metrology and high-precision measurement."
Professor Charlie Ironside of the School of Engineering at the University of Glasgow said: "The specialized optical diffraction gratings were co-designed by the groups in the collaboration and some of them were microfabricated in the James Watt Nanofabrication Centre at the University of Glasgow -- the work is a good example of how a team of physicists and engineers can collaborate to produce cutting edge technology."
The project was funded by the Engineering and Physical Sciences Research Council, ESA, the EU AQUTE project, the Wellcome Trust, the UK National Measurement Office, the Royal Society of Edinburgh and the Royal Society.
Researchers studying a filament of hydrogen between the Andromeda and Triangulum galaxies found rotating clumps of gas the size of dwarf galaxies. But questions remain.
By Pete Spotts / May 8, 2013
This combined graphic shows new, high-resolution GBT imaging of recently discovered hydrogen clouds between M31 (upper r.) and M33.
Bill Saxton, NRAO/AUI/NSF
Enlarge
New observations of a bridge of tenuous hydrogen gas stretching between two nearby galaxies may help solve a longstanding puzzle: Billions of years after star formation peaked in the universe, what continues to fuel the formation of new stars in spiral galaxies like the Milky Way?
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Newly published radiotelescope observations of this segment of what researchers have dubbed the ?cosmic web? reveal that about half of the neutral hydrogen gas in the bridge is contained in rotating clumps the size of dwarf galaxies. Neutral hydrogen ? atoms with one proton and one electron ? represents the raw material for new stars.
?If this gas is being accreted by the galaxies, then we need to understand how they're doing that. That information could, in principle, help us understand how galaxies like Andromeda, like our own Milky Way, can acquire gas to form new stars,? says Spencer Wolfe, a PhD candidate in astronomy at West Virginia University and the lead scientist on the project.
Over the past decade, astronomers have come to appreciate the potential of gas between galaxies to provide fresh fuel for making stars in spiral galaxies.
Star formation in the universe appears to have peaked some 10 billion to 11 billion years ago. Stellar birthrates these days are less than 10 percent of what they were then, notes Robert Braun, an astronomer at the Australia Telescope National Facility in Epping, New South Wales.
Left to their own devices, galaxies have on average about 1 billion to 2 billion years worth of gas in the cosmic tank, a condition that has existed throughout most of the universe's history, Dr. Braun writes in an e-mail. Many of them, therefore, should have stopped forming stars billions of years ago.?Moreover, the total mass of stars in the universe today is about five times higher than the amount of neutral hydrogen available 12 billion years ago, suggesting that the universe's larger inventory of ionized hydrogen kept star formation going in some way.
Researchers have identified other mechanisms for the galactic equivalent of in-flight refueling. For instance, gas gets recycled for a time through successive generations of stars. Collisions, mergers, and even near-misses between galaxies can trigger bursts of star formation.?But filaments of ionized hydrogen appear to be the only features persistent enough to keep galaxies stocked with stars over billions of years of cosmic history. Somehow, within those filaments, enough of the ionized gas condenses into the neutral form to serve as new stellar nurseries.
The filament or bridge Mr. Wolfe and his team studied appears between the Milky Way's nearest neighbor, the Andromeda Galaxy, and the Triangulum Galaxy. Andromeda is some 2.5 million light-years from Earth, while the Triangulum is roughly 3 million light-years away.
The presence of neutral hydrogen in the bridge was first reported in 2004 and confirmed in follow-up observations published last year. But it's fiendishly difficult to detect. One way neutral hydrogen betrays its presence is via radio waves, with a tell-tale signal at about the same frequency that a typical cell-phone uses. But the clumps are so wispy that their radio emissions were too faint for detailed studies with the radio telescopes used in the early work.
In this May 6, 2013 photo, Michael Gore, center, who is paralyzed from a spinal injury, walks with the use of the Indego wearable robot under the supervision of physical therapist Clare Hartigan during a meeting of the American Spinal Injury Association at a downtown hotel in Chicago. Eleven years ago, Gore was paralyzed from the waist down in a workplace accident, but with the aid of the 27-pound gadget that snaps together from pieces that fit into a backpack he stands and walks with the assistance of science and engineering. The device is among several competing products that hold promise for people with spinal injuries, like Gore, and for people with multiple sclerosis and cerebral palsy or for those recovering from strokes. (AP Photo/M. Spencer Green)
In this May 6, 2013 photo, Michael Gore, center, who is paralyzed from a spinal injury, walks with the use of the Indego wearable robot under the supervision of physical therapist Clare Hartigan during a meeting of the American Spinal Injury Association at a downtown hotel in Chicago. Eleven years ago, Gore was paralyzed from the waist down in a workplace accident, but with the aid of the 27-pound gadget that snaps together from pieces that fit into a backpack he stands and walks with the assistance of science and engineering. The device is among several competing products that hold promise for people with spinal injuries, like Gore, and for people with multiple sclerosis and cerebral palsy or for those recovering from strokes. (AP Photo/M. Spencer Green)
In this May 6, 2013 photo, Michael Gore, center, who is paralyzed from a spinal injury, walks with the use of the Indego wearable robot under the supervision of physical therapist Clare Hartigan during a meeting of the American Spinal Injury Association at a downtown hotel in Chicago. Eleven years ago, Gore was paralyzed from the waist down in a workplace accident, but with the aid of the 27-pound gadget that snaps together from pieces that fit into a backpack he stands and walks with the assistance of science and engineering. The device is among several competing products that hold promise for people with spinal injuries, like Gore, and for people with multiple sclerosis and cerebral palsy or for those recovering from strokes. (AP Photo/M. Spencer Green)
In this May 6, 2013 photo, Jennifer French, center, questions, Michael Gore, who is paralyzed from a spinal injury walking with the use of the Indego wearable robot under the supervision of physical therapist Clare Hartigan, second from left, during a meeting of the American Spinal Injury Association at a downtown hotel in Chicago. Eleven years ago, Gore was paralyzed from the waist down in a workplace accident, but with the aid of the 27-pound gadget that snaps together from pieces that fit into a backpack he stands and walks with the assistance of science and engineering. The device is among several competing products that hold promise for people with spinal injuries, like Gore, and for people with multiple sclerosis and cerebral palsy or for those recovering from strokes. (AP Photo/M. Spencer Green)
In this May 6, 2013 photo, Michael Gore, center, who is paralyzed from a spinal injury, walks with the use of the Indego wearable robot during a meeting of the American Spinal Injury Association at a downtown hotel in Chicago. Eleven years ago, Gore was paralyzed from the waist down in a workplace accident, but with the aid of the 27-pound gadget that snaps together from pieces that fit into a backpack he stands and walks with the assistance of science and engineering. The device is among several competing products that hold promise for people with spinal injuries, like Gore, and for people with multiple sclerosis and cerebral palsy or for those recovering from strokes. (AP Photo/M. Spencer Green)
In this May 6, 2013 photo, Michael Goldfarb, left, and Ryan Farris, co-inventors of the Indego wearable robot, speak during a meeting of the American Spinal Injury Association at a downtown hotel in Chicago. Their 27-pound invention snaps together from pieces and fits into a backpack and their goal is for the user to be able to carry it on a wheelchair, put it together, strap it on and walk independently. The device is among several competing products that hold promise for people with spinal injuries, like Gore, and for people with multiple sclerosis and cerebral palsy or for those recovering from strokes. (AP Photo/M. Spencer Green)
CHICAGO (AP) ? When Michael Gore stands, it's a triumph of science and engineering. Eleven years ago, Gore was paralyzed from the waist down in a workplace accident, yet he rises from his wheelchair to his full 6-foot-2-inches and walks across the room with help from a lightweight wearable robot.
The technology has many nicknames. Besides "wearable robot," the inventions also are called "electronic legs" or "powered exoskeletons." This version, called Indego, is among several competing products being used and tested in U.S. rehab hospitals that hold promise not only for people such as Gore with spinal injuries, but also those recovering from strokes or afflicted with multiple sclerosis and cerebral palsy.
Still at least a year away from the market, the 27-pound Indego is the lightest of the powered exoskeletons. It snaps together from pieces that fit into a backpack. The goal is for the user to be able to carry it on a wheelchair, put it together, strap it on and walk independently. None of the products, including the Indego, are yet approved by federal regulators for personal use, meaning they must be used under the supervision of a physical therapist.
Gore, 42, of Whiteville, N.C., demonstrated the device this week at the American Spinal Injury Association meeting in Chicago, successfully negotiating a noisy, crowded hallway of medical professionals and people with spinal injuries in wheelchairs.
When he leans forward, the device takes a first step. When he tilts from side to side, it walks. When Gore wants to stop, he leans back and the robotic leg braces come to a halt. Gore uses forearm crutches for balance. A battery in the hip piece powers the motors in the robotic legs.
"Being able to speak with you eye-to-eye is just a big emotional boost," Gore said to a reporter. "Being able to walk up to you and say hello is not a big thing until you cannot do it."
The devices won't replace wheelchairs, which are faster. None of the devices are speedy enough, for example, for a paralyzed person to walk across a street before the light changes, said Arun Jayaraman of the Rehabilitation Institute of Chicago, who is testing a number of similar devices.
"None of them have fall prevention technology," Jayaraman said. "If the person falls, they can hurt themselves badly. If you fall down, how do you get off a robot that is strapped into you?" They need to be even lighter and have longer-lasting batteries, he said.
Still, Jayaraman said, the devices might help prevent pressure sores from sitting too long in a wheelchair, improve heart health, develop muscle strength, lift depression and ultimately bring down medical costs by keeping healthier patients out of the hospital.
Companies in Israel, New Zealand and California make competing devices, and all the products are becoming less bulky as they are refined. The Indego was invented at Vanderbilt University in Nashville and tested at the Shepherd Center, a rehabilitation hospital in Atlanta. It's now licensed to Cleveland-based Parker Hannifin Corp., which makes precision engineered products like aircraft wheels and brakes.
Like many other research participants in clinical studies, Gore receives a stipend for his participation from Vanderbilt University.
It's unclear exactly how much the devices will cost if they become available for personal use. Some technology news media reports have said $50,000 to $75,000. Indego's makers want to bring the cost below that, said co-inventor Ryan Farris of Parker Hannifin. Experts say it will take years of research to prove health benefits before Medicare and private insurance companies would consider covering the expense.
Paul Tobin, president of the nonprofit advocacy group United Spinal, said wearable robots present an exciting opportunity but that patients should keep their expectations realistic.
"It's going to be critical that people have a thorough medical evaluation before trying something like this, especially if they've been injured for some time," Tobin said. "It won't be appropriate for everyone. For some people, it will be a godsend."
___
AP Medical Writer Carla K. Johnson can be reached at http://www.twitter.com/CarlaKJohnson
An Alvar beach in Manitoulin, Ontario ? one of several sites studied for the IUCN's new Red List of endangered ecosystems.
By Becky Oskin, OurAmazingPlanet
With many of the world's ecosystems threatened or endangered by human activities like logging and urbanization, the International Union for Conservation of Nature (IUCN) published its criteria for a new "Red List" of endangered ecosystems Wednesday in the journal PLOS ONE.
The list, which measures an ecosystem's risk of collapse, will be similar to the group's authoritative Red List of Endangered Species, which created internationally accepted criteria for assessing extinction risk.
"The Red Lists for species and ecosystems will together provide a more comprehensive view of the status of the environment and its biodiversity than either can on its own," said lead study author David Keith, a professor at the University of New South Wales in Australia.
"The Ecosystem Red List focuses on a high level of biodiversity, the habitats for species, as well as their interactions and dependencies, including food webs,? Keith told OurAmazingPlanet in an email interview. ?These are difficult or impossible to address in Red List assessments of individual species, but very important for the functioning of ecosystems and the services that they provide to support our standards of living."
Through 20 case studies, Keith and an international team of biologists and conservationists designed criteria that could assess the health of all of Earth's varied ecosystems, from spring-fed limestone caves to sparkling coral reefs.
"This is really a unifying framework," said study co-author Richard Kingsford, also a professor at the University of New South Wales. "The most important thing here, from my point of view, is providing evidence that pushes governments to do things to protect these magnificent parts of the world."
Of the ecosystems examined in the case studies, the most endangered site was the Aral Sea. Drained by a massive irrigation project and further devastated by drought and pollution, the inland sea's ecosystem has collapsed ? the equivalent of species extinction, the study concludes.The rest of the ecosystem threat categories mirror those for species: critically endangered, endangered, vulnerable and least concern.
North American ecosystems appearing in the case studies included Alaska's giant kelp forests; the Great Lakes' rare Alvar beaches, a legacy of glaciers grinding across the landscape; and Caribbean coral reefs.
The IUCN group that developed the Red List of Ecosystems criteria plans to formally propose the framework to IUCN leadership this year. Funding is in place for listing ecosystems in the Americas, and the organization hopes to have a global list in place by 2025.
Development of ecosystem and species Green Lists are also underway ? the carrot to the Red Lists' stick ? to help the IUCN promote conservation by rewarding successes.
Here are the 20 case studies published today, from most to least endangered, with the ecosystem type noted if available.
Aral Sea ? Uzbekistan and Kazakhstan: freshwater, collapsed
Raised bogs ? Germany: critically endangered
Gonakier forests ? Senegal River floodplain: freshwater, critically endangered
Cape Sand Flats ? Fynbos, South Africa: terrestrial, critically endangered
Great Lakes Alvars ? United States and Canada: terrestrial, vulnerable/endangered
Reed beds ? Europe: freshwater, vulnerable
Floodplain ecosystem of river red gum and black box ? southeastern Australia: freshwater, vulnerable
Tepui shrubland - Venezuela: terrestrial, least concern
Granite gravel fields and sand plains - New Zealand: terrestrial, least concern
Email Becky Oskin or follow her @beckyoskin. Follow us?@OAPlanet, Facebook?& Google+. Original article on LiveScience's OurAmazingPlanet.
Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
All Europeans are related, sharing a common ancestor as recently as 1,000 years ago, according to a gene study published today.
By Tia Ghose,?Live Science Staff Writer / May 7, 2013
Maps that show where the distant cousins of modern-day people in the UK live, at three different levels of relatedness (recent on top, older on the right, oldest on the bottom). Bigger circles mean more ancestors, and numbers give average number of shared genetic alleles.
Ralph P, Coop G/PLOS ONE
Enlarge
Europeans all shared a common ancestor just 1,000 years ago, new genetic research reveals.
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Scientists drew this conclusion, detailed today (May 7) in the journal PLOS Biology, by calculating the length of regions of shared DNA from 2,000 Europeans.
The same technique hasn't been applied to other continents, but people in other parts of the world are just as likely to be closely related, the researchers said.
"In fact, it's likely that everyone in the world is related over just the past few thousand years," said study co-author Graham Coop, a geneticist at the University of California, Davis.?
All in the family
For more than a decade, researchers calculated theoretically that all people shared common ancestors fairly recently.
To test that theory, Coop and his colleagues analyzed 500,000 spots on the genome of Europeans, from Turkey to the United Kingdom. To untangle European ancestry, they calculated the length of shared segments of DNA, or the molecules that contain the genetic instructions for life. When two people share a longer stretch of identical DNA, they are likely to share a more recent common ancestor, since over time those gene segments evolve and diversify.
The researchers found that all Europeans shared a common ancestor just 1,000 years ago.
There were also some regional surprises.
For instance, Italians are slightly less related to one another than people from other European countries are to one another, perhaps because Italians have had a large, fairly stable population for a few thousand years.
In addition, people from the United Kingdom are more related to people from Ireland than they are to other people from the United Kingdom. That's possibly because many people have migrated from the smaller country of Ireland to the bigger United Kingdom in the past several hundred years, Coop told LiveScience.
The researchers also showed that people in Eastern Europe were slightly more related to each other than were those in Western Europe.
Recent history
That may be he signature of Slavic expansion and migrations, such as those of the Huns and the Goths, about 1,000 years ago, said John Novembre, a population geneticist at the University of Chicago, who was not involved in the study.
The new findings are exciting because they allow researchers to trace much more recent human history.
"In the past human geneticists have been able to focus on the types of population movement that have taken place over tens of thousands of years ? like moving out of Africa and into Eurasia," Novembre told LiveScience. "They're starting to see population movements that have taken place in the middle ages."
Follow Tia Ghose on Twitter @tiaghose.?Follow?LiveScience @livescience, Facebook?& Google+. Original article on?LiveScience.com.
Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Hubble finds dead stars 'polluted' with planetary debrisPublic release date: 9-May-2013 [ | E-mail | Share ]
Contact: Nicky Guttridge nguttrid@partner.eso.org 49-893-200-6855 ESA/Hubble Information Centre
The stars, known as white dwarfs small, dim remnants of stars once like the Sun reside 150 light-years away in the Hyades star cluster, in the constellation of Taurus (The Bull). The cluster is relatively young, at only 625 million years old.
Astronomers believe that all stars formed in clusters. However, searches for planets in these clusters have not been fruitful of the roughly 800 exoplanets known, only four are known to orbit stars in clusters. This scarcity may be due to the nature of the cluster stars, which are young and active, producing stellar flares and other outbursts that make it difficult to study them in detail.
A new study led by Jay Farihi of the University of Cambridge, UK, instead observed "retired" cluster stars to hunt for signs of planet formation [1].
Hubble's spectroscopic observations identified silicon in the atmospheres of two white dwarfs, a major ingredient of the rocky material that forms Earth and other terrestrial planets in the Solar System. This silicon may have come from asteroids that were shredded by the white dwarfs' gravity when they veered too close to the stars. The rocky debris likely formed a ring around the dead stars, which then funnelled the material inwards.
The debris detected whirling around the white dwarfs suggests that terrestrial planets formed when these stars were born. After the stars collapsed to form white dwarfs, surviving gas giant planets may have gravitationally nudged members of any leftover asteroid belts into star-grazing orbits [2].
"We have identified chemical evidence for the building blocks of rocky planets," says Farihi. "When these stars were born, they built planets, and there's a good chance that they currently retain some of them. The signs of rocky debris we are seeing are evidence of this it is at least as rocky as the most primitive terrestrial bodies in our Solar System."
Besides finding silicon in the Hyades stars' atmospheres, Hubble also detected low levels of carbon. This is another sign of the rocky nature of the debris, as astronomers know that carbon levels should be very low in rocky, Earth-like material. Finding its faint chemical signature required Hubble's powerful Cosmic Origins Spectrograph (COS), as carbon's fingerprints can be detected only in ultraviolet light, which cannot be observed from ground-based telescopes.
"The one thing the white dwarf pollution technique gives us that we won't get with any other planet detection technique is the chemistry of solid planets," Farihi says. "Based on the silicon-to-carbon ratio in our study, for example, we can actually say that this material is basically Earth-like."
This new study suggests that asteroids less than 160 kilometres across [3] were gravitationally torn apart by the white dwarfs' strong tidal forces, before eventually falling onto the dead stars [4].
The team plans to analyse more white dwarfs using the same technique to identify not only the rocks' composition, but also their parent bodies. "The beauty of this technique is that whatever the Universe is doing, we'll be able to measure it," Farihi said. "We have been using the Solar System as a kind of map, but we don't know what the rest of the Universe does. Hopefully with Hubble and its powerful ultraviolet-light spectrograph COS, and with the upcoming ground-based 30- and 40-metre telescopes, we'll be able to tell more of the story."
###
Notes
1] The two "polluted" Hyades white dwarfs are part of a search of planetary debris around more than 100 white dwarfs, led by Boris Gnsicke of the University of Warwick, United Kingdom. Using computer models of white dwarf atmospheres, Detlev Koester from the University of Kiel in Germany is determining the abundances of various elements that can be traced to planets in the COS data.
[2] Seeing evidence of asteroids points to the possibility of Earth-sized planets in the same system. Asteroids are the building blocks of major planets. Planet-forming processes are inefficient, and spawn many times more small bodies than large bodies but once rocky embryos the size of asteroids are built, planets are sure to follow.
[3] The team estimated the size of the infalling asteroids by measuring the amount of dust being gobbled up by the stars about 10 million grams per second, equal to the flow rate of a small river. They then compared that data with measurements of material falling onto other white dwarfs.
[4] The Hyades study offers insight into what will happen in the Solar System when the Sun burns out, five billion years from now.
Notes for editors
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
[1] The international team of astronomers in this study consists of J. Farihi (University of Cambridge, UK; STFC Ernest Rutherford Fellow), B. T. Gnsicke (University of Warwick, UK), D. Koester (University of Kiel, Germany).
[2] The new study is appearing in the Monthly Notices of the Royal Astronomical Society.
More information
Image credit: NASA, ESA, STScI and G. Bacon (STScI)
Links
Contacts
Jay Farihi
Institute of Astronomy, University of Cambridge
Cambridge, UK
Tel: +44 (0)12 2333 0896
Email: jfarihi@ast.cam.ac.uk
Robert Massey
Royal Astronomical Society
London, UK
Tel: +44 (0)20 7734 3307
Cell: +44 (0)794 124 8035
Email: rm@ras.org.uk
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.
Hubble finds dead stars 'polluted' with planetary debrisPublic release date: 9-May-2013 [ | E-mail | Share ]
Contact: Nicky Guttridge nguttrid@partner.eso.org 49-893-200-6855 ESA/Hubble Information Centre
The stars, known as white dwarfs small, dim remnants of stars once like the Sun reside 150 light-years away in the Hyades star cluster, in the constellation of Taurus (The Bull). The cluster is relatively young, at only 625 million years old.
Astronomers believe that all stars formed in clusters. However, searches for planets in these clusters have not been fruitful of the roughly 800 exoplanets known, only four are known to orbit stars in clusters. This scarcity may be due to the nature of the cluster stars, which are young and active, producing stellar flares and other outbursts that make it difficult to study them in detail.
A new study led by Jay Farihi of the University of Cambridge, UK, instead observed "retired" cluster stars to hunt for signs of planet formation [1].
Hubble's spectroscopic observations identified silicon in the atmospheres of two white dwarfs, a major ingredient of the rocky material that forms Earth and other terrestrial planets in the Solar System. This silicon may have come from asteroids that were shredded by the white dwarfs' gravity when they veered too close to the stars. The rocky debris likely formed a ring around the dead stars, which then funnelled the material inwards.
The debris detected whirling around the white dwarfs suggests that terrestrial planets formed when these stars were born. After the stars collapsed to form white dwarfs, surviving gas giant planets may have gravitationally nudged members of any leftover asteroid belts into star-grazing orbits [2].
"We have identified chemical evidence for the building blocks of rocky planets," says Farihi. "When these stars were born, they built planets, and there's a good chance that they currently retain some of them. The signs of rocky debris we are seeing are evidence of this it is at least as rocky as the most primitive terrestrial bodies in our Solar System."
Besides finding silicon in the Hyades stars' atmospheres, Hubble also detected low levels of carbon. This is another sign of the rocky nature of the debris, as astronomers know that carbon levels should be very low in rocky, Earth-like material. Finding its faint chemical signature required Hubble's powerful Cosmic Origins Spectrograph (COS), as carbon's fingerprints can be detected only in ultraviolet light, which cannot be observed from ground-based telescopes.
"The one thing the white dwarf pollution technique gives us that we won't get with any other planet detection technique is the chemistry of solid planets," Farihi says. "Based on the silicon-to-carbon ratio in our study, for example, we can actually say that this material is basically Earth-like."
This new study suggests that asteroids less than 160 kilometres across [3] were gravitationally torn apart by the white dwarfs' strong tidal forces, before eventually falling onto the dead stars [4].
The team plans to analyse more white dwarfs using the same technique to identify not only the rocks' composition, but also their parent bodies. "The beauty of this technique is that whatever the Universe is doing, we'll be able to measure it," Farihi said. "We have been using the Solar System as a kind of map, but we don't know what the rest of the Universe does. Hopefully with Hubble and its powerful ultraviolet-light spectrograph COS, and with the upcoming ground-based 30- and 40-metre telescopes, we'll be able to tell more of the story."
###
Notes
1] The two "polluted" Hyades white dwarfs are part of a search of planetary debris around more than 100 white dwarfs, led by Boris Gnsicke of the University of Warwick, United Kingdom. Using computer models of white dwarf atmospheres, Detlev Koester from the University of Kiel in Germany is determining the abundances of various elements that can be traced to planets in the COS data.
[2] Seeing evidence of asteroids points to the possibility of Earth-sized planets in the same system. Asteroids are the building blocks of major planets. Planet-forming processes are inefficient, and spawn many times more small bodies than large bodies but once rocky embryos the size of asteroids are built, planets are sure to follow.
[3] The team estimated the size of the infalling asteroids by measuring the amount of dust being gobbled up by the stars about 10 million grams per second, equal to the flow rate of a small river. They then compared that data with measurements of material falling onto other white dwarfs.
[4] The Hyades study offers insight into what will happen in the Solar System when the Sun burns out, five billion years from now.
Notes for editors
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
[1] The international team of astronomers in this study consists of J. Farihi (University of Cambridge, UK; STFC Ernest Rutherford Fellow), B. T. Gnsicke (University of Warwick, UK), D. Koester (University of Kiel, Germany).
[2] The new study is appearing in the Monthly Notices of the Royal Astronomical Society.
More information
Image credit: NASA, ESA, STScI and G. Bacon (STScI)
Links
Contacts
Jay Farihi
Institute of Astronomy, University of Cambridge
Cambridge, UK
Tel: +44 (0)12 2333 0896
Email: jfarihi@ast.cam.ac.uk
Robert Massey
Royal Astronomical Society
London, UK
Tel: +44 (0)20 7734 3307
Cell: +44 (0)794 124 8035
Email: rm@ras.org.uk
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The technology industry’s newest high-powered political lobby, FWD.us, is unraveling just a month after it launched, as two of its biggest partners, Tesla’s Elon Musk and Yammer’s David Sacks, leave the organization. Begun with a reported $20 million of Mark Zuckerberg’s own money, and rare op-ed by the politically shy Facebook founder, FWD.us has faced a torrent of criticism over funding advertisements that praise Republicans who support the controversial Keystone pipeline (below). Environmental groups were up in arms and circulated a boycott of FWD.us that had, ironically, had more supporters than FWD.us’s call to action. The Sierra Club, Progressives United and MoveOn.org were among a littany of progressive groups that are now boycotting Facebook?advertisements.? ?Immigration reform ? fine. Oil expansion and pipelines? NOT fine. Where?s the transparency here, rich dudes? Or does FWD actually stand for Fine With Drilling?,? wrote one angry commenter on the FWD.us Facebook page. Elon Musk, as founder of Tesla Motors, prides himself on a sterling environmental record, so it’s easy to see why he couldn’t tolerate being associated with a group indirectly funding pro-Keystone pipeline ads. But, David Sacks doesn’t have as much to lose publically as Musk, which means that Musk is likely hooking more high-level partners with his departure. Nor is this the group’s first PR disaster. Even before the group began, FWD.us director and Zuckerberg’s old Harvard roommate, Joe Green, had to issue a statement of regret for a leaked perspectus. “Given the status of our funders and quality of our team, we will drive national and local narratives to properly frame our agenda,” read the brash strategy note. As we’ve written about before, FWD.us has kept a tight lid on their funding and tactics. We do know that FWD.us splits its organization into Democratic and Republican teams, offering quid pro quo cash in exchange for support of its key initiative — immigration. This kind of back-door compromising may work in D.C., but it’s evidently not as well tolerated in the Valley. In my own off-the-record conversations with supporters, no one is happy with FWD.us right now. It’s going to become a political landmine to stay on board, let alone join the group. FWD.us is unraveling, and we predict it won’t be around much longer unless it becomes a lot more transparent and ditches the D.C. tactics. Stay tuned for more.
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Public release date: 9-May-2013
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