In The Field nature.com homepage Nature NewsblogNature Newsblog All the action from the world’s hottest science events as it happens, brought to you by Nature News.NOTE: The newsblog as it existed from January 2006 to August 2007 is no more. If you want to comment on a News story, you can now do so at the foot of the story itself. If you are hunting for older comments you'll find them archived here. AAS 2009: Pulsars spinning, on the dance floor  “Do you realize that we are up to our 11th year of parties?” says Gina Brissenden, who was hemmed within a scrum of astronomers on the patio, but utterly pleased about it. Hundreds of astronomers had turned out to the Rhythm Lounge in Long Beach, and were rapidly starting to get their groove on (aided and abetted by the 'Galileo 400' drink special). What began as an impromptu afterparty in a hotel room, organized by Gina, has since turned into a biannual bacchanalia for the young, the old; for those inclined to dance, and for those who you wish weren't so inclined.Above the dance floor, an endless short film loop was projected -- about the discovery of the period-luminosity function for Cepheid variables. I was pretty sure that it was entirely incidental, however, when the DJ played the Beastie Boys song, “Intergalactic.”They didn't need any help on the dance floor anyway. Astronomers are an interesting bunch. Individualists, each and every one of them, but as a fellow observer remarked to me: she had never seen a pack of people devote themselves so quickly and diligently to the collective task of getting down. The dance floor was a black hole, and at one point, there were demands that astronaut John Grunsfeld occupy its singularity (that he might be more concerned about fixing the Hubble space telescope was not an issue). “I heard there were astronomers in the house,” says Kevin Marvel, AAS executive officer, revving up the crowd from the DJ booth. With just a hint of cautionary worry, he implores them: “Don't go supernova.” Allright folks, it's been a pleasure, and it's time for me to catch a plane back to Washington, DC. And in case you were wondering what's in a 'Galileo 400', it's vodka, peach schnapps, and Sprite. Posted by Eric Hand at 04:15 PM | Permalink AAS 2009: Don't be shy, cuddle up to an M dwarf  Some 70% of the stars in the galaxy are M dwarfs, and so exoplanet surveys will be targeting these relatively cool, small stars. But the habitable zone for Earth-like planets in these systems will be at least five times closer to the M dwarf than the Earth is to the sun. That keeps the planet warm, but also subjects it to the star's capricious behavior. “They flare as powerfully or even more so than the Sun,” says Lucianne Walkowicz, of the University of California at Berkeley, who gauged the effects of an M dwarf flare on planetary habitability in an AAS poster session. “People assumed that this would just sterilize the planet.”Lucianne modeled a 4-hour flare -- a classic one that astronomers had observed carefully on a nearby M dwarf --and calculated its effects on an Earth-like planet, with an Earth-like atmosphere, orbiting at 0.16 astronomical units -- six times closer than the Earth is to the Sun. She measured the effect of the flare -- which for our Sun, can rise up to heights 50 times the diameter of the Earth -- on temperature, ozone, UV flux and water vapour. Turns out, the flare wasn't that big of a deal. Temperatures only changed a tenth of a degree. Most of the energy of the flare went into the upper atmosphere where it broke down ozone. The fraction of the radiation that did make it through, she says, is less than you'd get on a sunny day walking around Earth. Posted by Eric Hand at 08:43 AM | Permalink AAS 2009: The death rattle of the first stars? The 10-foot-tall tub, full of 500 gallons of liquid helium, dangled underneath a high-altitude balloon over the skies of Texas for just a few hours. But the bucket came back with a big mystery.In the 2006 flight, Alan Kogut of Goddard Space Flight Center in Greenbelt, Maryland and his colleagues were aiming to use the seven super-cooled antennae in the tub to hear the faint, relic radio signal of 'first light', the epoch a few hundred million years after the Big Bang when big lumbering stars ruled the roost. But instead, they heard a really loud radio hiss. “To our surprise, we found an unexplained radio static... that fills the early universe and is currently unexplained,” says Kogut, speaking at a press briefing on Wednesday.Astronomers, using balloons and satellites, have mapped the cosmic microwave background -- the faint, 2.7 degree Kelvin fabric created by the Big Bang itself -- at slightly shorter wavelengths, and ground based astronomers have conducted radio survey at longer wavelengths. But Kogut says his group was the first to notice something in this strange, in-between regime. In four papers submitted to the Astrophysical Journal, they are careful to rule out the possibility that the radio background signal came from the Milky Way. It's much bigger than the total signal from all known radio galaxies, and it's way too big to have anything to do with the first light stars (they would have looked for the radio signal associated with hot gas near these first stars). But they were reluctant to speculate what it could be. “We really don't know,” Kogut says. The balloon experiment didn't have much resolving power to pinpoint individual sources of the static, and it only looked at a few frequencies. Pressed for ideas, Kogut said that it could be radio radiation from the collapse of these huge, first stars into black holes. There would have hundreds, if not thousands, of these first stars in each proto-galaxy, he says, and their collective death rattle, so many of them across the sky, just might appear as a background signal to his relatively crude balloon instrument. “We may have accidentally backed into the epoch we were interested in.” It would be the first signal from one of the deepest, and heretofore darkest, reaches of the universe.I was just pleased to see yet again that simple balloon experiments can have a potentially big impact. At $4 million, the experiment, called ARCADE, is another example of how cost effective balloons can be. Posted by Eric Hand at 01:50 AM | Permalink AAS 2009: Fermi finds new pulsar classes  In just a matter of months, the Fermi gamma ray observatory since its launch has found dozens of new pulsars -- spinning, magnetized remnants of supernovae -- that emit a flashing signal in the gamma-ray part of the spectrum only. This new class of pulsar has revolutionized scientists' view of its general structure: Early in a pulsar's lifetime, it blasts a broad gamma-ray signal rather than a narrow polar one, as was previously thought. The findings, announced Tuesday at AAS, also includes a club within a club: a subclass of the gamma-ray-only pulsars that flash exceptionally quickly, an indication that they are revving up as they partially devour their dying partners in binary star systems.The supernovae that come at the end of a star's life cast off much of a star's mass, but what's left collapses to form a neutron star, a fantastically dense object just shy of being a black hole. The spinning magnetic fields produce a narrow cone of radio waves that jet out from the poles. Some 1,800 radio pulsars have been discovered this way. But there were only a handful that also produced gamma-rays, and these signals were also thought to emanate from the poles. Fermi has boosted the number of known gamma-ray pulsars up to 38, including 13 that lack a radio signal altogether -- an indication that the gamma rays can't be coming from the poles. The results, says mission scientist Roger Romani of Stanford University, “have put the nail in the coffin of the polar cap model.”He is still working out the mechanisms and geometries by which the intense magnetic fields create the powerful gamma-ray signal, which is expected to arise only in the first million years or so of the pulsar's life. His models show a trumpet-like bell shape that emerges and sweeps across the pulsar's face, higher in its magnetosphere, rather than only at the poles. “It means the gamma rays are being beamed widely across the sky,” he says. The newest phenomenon -- seven so-called 'millisecond' pulsars that flash hundreds of times faster than normal -- has led mission scientist Alice Harding, of Goddard Space Flight Center, to envision how this happens. In binary stars systems -- relatively common in the universe -- one may die first and become a pulsar. Before the second star explodes, it expands, and its excess material can be sucked into the spinning maw of the pulsar thereby speeding it up. “These guys must have strong stomachs,” Harding says. That's the scenario pictured here. After the jump, Fermi's all sky map, and the new gamma-ray pulsars. Continue reading "AAS 2009: Fermi finds new pulsar classes" » Posted by Eric Hand at 05:47 AM | Permalink AAS 2009: An Australian Space Agency? Dr. Penny Sackett began her term as Australia's chief scientist in November 2008 -- a government position akin to the presidential science adviser in the US -- but still feels enough of an allegiance to the community from which she hails (astronomy) to come and give an invited talk at AAS on Tuesday. Towards the end of the talk, which was an overview of Australian science and its place in the world, she mentioned in passing that the government is considering establishing a national space agency. After the talk, I asked her about it, and she said that the government is expected to deliver a white paper on the subject early this year, which would be a first step towards any eventual parliamentary establishment. She said if it does happen, it would be an agency more so than a funding program. Posted by Eric Hand at 02:09 AM | Permalink AAS 2009: A century of night  Many AAS sessions here are emphasizing temporal astronomy -- the idea that the heavens are by no means as static as was once thought. Two new projects, LSST and Pan-STARRS, will exploit wide fields of view and scan vast swaths of the sky night after night in the hopes of catching variable stars, supernovae, pulsars, even the occasional killer asteroid. While these projects look to the future, there is already a century's worth of information at hand, waiting to be tapped. The Harvard Plate stacks contain half a million photographic plates, dating back to 1885. That's 1.5 petabytes of data that Josh Grindlay, of Harvard Smithsonian Observatory, is eager to recover and rehabilitate in a project called DASCH. The plates, created in early, and often jungly, telescopic expeditions to both hemispheres, were brought back to the US, where 'computers' -- small armies of women -- hunched over the plates and performed the grueling task of cataloging them.Now Grindlay wants to digitize them, and fold them into a universal coordinate system using a special software that can synchronize just about any picture of the sky to the right time or place. They have already built what he describes as the world's fastest scanner, capable of scanning one 8 x 12 inch plate a minute. All he needs is a cool $4 million, so he can hire 10 people to do the manual feeding of the scanner. “We're begging to be done,” he says.He says he's had interest from Google and Microsoft, and he is also trying to approach foundations and invidual benefactors, but so far, no one has offered the money. C'mon millionaires, cough it up: DASCH is clearly an acronym that can disappear. Would you rather have your name on a century's worth of sky, or a yacht? Here's an image taken in 1896 with an 8-inch telescope in Arequipa, Chile, that happened to catch an alien invader in the act.Image: DASCH Posted by Eric Hand at 03:45 PM | Permalink | Comments (1) | TrackBacks (0) AAS 2009: Behold: the Milky Way The sharpest images yet of the central 300 light-years of our galaxy, courtesy Spitzer and Hubble space telescopes. Say no more. Image: NASA / ESA / Q.D.Wang / JPL / S.Stolovy Posted by Eric Hand at 06:34 AM | Permalink AAS 2009: Brown dwarfs ain't so brown  Kenneth Brecher, an astrophysicist at Boston University, gave a funny little talk today called 'How now brown cow dwarf'. The title of his talk, he says, is as meaningless as the term 'brown dwarf'. It's one of his many concerns with light perception at Project LITE, an umbrella for the psychophysical color experiements he runs.'Brown dwarf' was coined in the 1970s by Jill Tarter, now director of the SETI institute, and it was a term that stuck. “It was a mistake,” says Brecher. “'Infrared dwarfs' would have been a much better name.”The problem is that brown is a subtractive color -- made by 'desaturating' yellows and oranges with black. But since brown dwarfs are emissive bodies -- they glow -- they by definition can't be brown.Now Brecher knows that he's not going to change astronomers from using a term that is so much a part of the vernacular. But just like many involved in the debate over what constitutes a planet, Brecher seems to be a scientist who cares very much about names and definitions. “Astronomy is riddled with historical artifacts that nobody in their right mind would use today.”Here is Brecher holding a neon light, glowing with the color that he says we would perceive a brown dwarf emitting: yellowish-orange. Note, however, that Brecher is wearing a brown jacket. Posted by Eric Hand at 06:08 AM | Permalink AAS 2009: The blogiverse Lots of press people in attendance, but I would venture to say that, given the economy in general and the layoffs that have gutted the media in particular, there are fewer now than in years before. There are more public affairs officers than there are reporters, and so far, I have not seen a single newspaper reporter. There aren't too many live blogging the conference, either, as far as I can tell. Victoria Jaggard appears to be blogging a bit at National Geographic. And Wired science and Discover's Phil Plait are both blogging from distance, tuning into the press conferences streamed here. Anyone else out there? Posted by Eric Hand at 05:05 AM | Permalink AAS 2009: Glowing graveyards  The glowing graveyard of rubble that surrounds some dying 'white dwarf' stars is providing astronomers with clues to the composition of rocky extrasolar planetary systems. By looking at the faintly glowing, shredded remnants of asteroids that surround distant white dwarfs, astronomers at the University of California at Los Angeles are finding that they have similar chemical compositions to rocky planets and asteroids closer to home – in the inner solar system. “We have a tool for measuring the bulk composition of the planets,” UCLA's Michael Jura said at a AAS press conference on Monday. “It strengthens suspicions that Earth-like planets are common.”Geologists, Jura says, have long known that the Earth is rich in silica minerals, but poor in carbon, relative to the overall chemical composition of the sun. But whether that discrepancy holds elsewhere in the universe has been, until recently, a mystery. “Astronomers tend not to think about this,” he says. Using the Spitzer Space Telescope, Jura and others have assembled a small catalog of white dwarf stars that have rubble disks that glow brightly enough so that astronomers can tease out chemical compositions from their spectra. The latest white dwarf system, presented on Monday, brings the total up to eight.Jura showed a spectrum with a clear bump in the prevalence of silicate minerals – and a lack of carbon. This means that the inner solar systems of extrasolar systems might not be terribly different from our own. Jura's work has been accepted for publication in the Astrophysical Journal. Image: NASA/JPL-Caltech/M.Jura Posted by Eric Hand at 08:26 PM | Permalink Search this blog: Main navigation Subscribe Subscribe to this blog's feeds: Blog Posts Blog Posts & Comments [What is this?] Categories About Nature News About this blog Conference reports European Society of Human Reproduction & Embryology African Union Summit American Association for Cancer Research American Association for the Advancement of Science American Astronomical Society American Chemical Society American Geophysical Union American Heart Association American Physical Society American Society for Cell Biology American Society for Reproductive Medicine American Society of Human Genetics American Society of Microbiology Animal Behavior Society Carbon Market Insights conference Earth System Science Partnership Ecological Society of America Emerging technologies European Chemistry Congress European Geosciences Union Euroscience Open Forum Federation of European Neuroscience Societies Human Genome Organisation International AIDS conference International Astronomical Union International Society for Stem Cell Research International Union for Quaternary Research Lunar and Planetary Science Materials Research Society Poznan climate-change conference Primate genomics and human disease Society for American Archaeology Society for Conservation Biology Society for Developmental Biology Society for Neuroscience Society for the Study of Reproduction Synthetic Biology World Conference of Science Journalists World Conference on Research Integrity ESOF08 Events Awards Bird watching Canadian icebreaker Climate war game Everest expedition Global Seed Vault opening Mid-term elections 2006 NASA Phoenix Landing Performance art Space shuttle Atlantis launch Starting the LHC Recent Posts AAS 2009: Pulsars spinning, on the dance floor AAS 2009: Don't be shy, cuddle up to an M dwarf AAS 2009: The death rattle of the first stars? AAS 2009: Fermi finds new pulsar classes AAS 2009: An Australian Space Agency? Out of 5167 total comments, the most recent were: Charles Weber on AGU: Geoengineering costs Video Conference on Phoenix landing: A tale of two telltales Doug Borsom on AAS 2009: A century of night Recommended LinksNature NewsNature News archiveNature JournalThe Great BeyondNature Blogs Archives January 2009 December 2008 November 2008 October 2008 September 2008 August 2008 July 2008 June 2008 May 2008 April 2008 March 2008 February 2008 January 2008 December 2007 November 2007 October 2007 September 2007 August 2007 July 2007 June 2007 May 2007 April 2007 March 2007 February 2007 January 2007 December 2006 November 2006 October 2006 September 2006 August 2006 July 2006 June 2006 May 2006 April 2006 March 2006 February 2006 January 2006  |
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