“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 on January 08, 2009
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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 on January 08, 2009
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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 on January 08, 2009
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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 on January 07, 2009
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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 on January 07, 2009
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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 on January 06, 2009
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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 on January 06, 2009
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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 on January 06, 2009
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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 on January 06, 2009
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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 on January 05, 2009
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Welome to Long Beach, California for the 2009 conference of the American Astronomical Society. This means, at least for me, palm trees in January. They've also shipped in a container-load of astronomers, here in Long Beach, south of Los Angeles, the site of one of the largest ports in the world. There are 2,450 registrants so far, according to AAS staff. It's a beautiful day out there, but most of us are in the basement of the conference center listenting to AAS president John Huchra greet us.

It's five days after the new year, and thus five days into the International Year of Astronomy, or IYA for short. I have yet to hear this acronym pronounced out loud, but I hope that it is said 'eee-yah', like a cross between 'hell yeah!' and 'enya'. That accurately describes my feelings about astronomy – it takes the excitment of discovering new worlds and sets it to a backdrop of ethereal lounge music.

But John Huchra just pronounced it 'eye why ay' – and this makes sense too, because the reason for the IYA is that it is the 400th birthday of Galileo's telescope: the first eye on the sky, and the instrument that led to many 'why' questions. Looking forward to hearing new why questions this week.

Posted by Eric Hand on January 05, 2009
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If you didn't realize it, Ithaca was a good place for DPS. Cornell put on a concert for the planets. The art museum has a special Saturn exhibit going. But one of my favorite things is down the hill from Cornell: the planet walk. Named in honor of Carl Sagan, the planet walk was unveiled in 1997, but has a slightly retro, 1970s feel to it. A little hokey, but endearingly earnest and fun nonetheless. You start at the heart of the Ithaca Commons, downtown, with a concrete monument to the sun, adorned with factoids. A circular hole within the monument sets the scale: that is the diameter of the sun, at one 5-billionth of its size. The planets, each with their own monument, stretch out from there, their distances based proportionately on their orbits. I decided to go for a jog out to Pluto, to really get a sense of the solar system's scale.

The inner planets all lie within a block. Jupiter, the size of a silver dollar in its sun-sized hole, sits by the famous vegetarian Moosewood Restaurant a couple blocks away. Saturn, its plastic all scratched up, is further out, in front of the Tompkins County library. I only had to run for less than 10 minutes to get this far, but the next stages of the jog were daunting. Uranus was in a little residential park, Neptune out along a canal that leads to Lake Cayuga. Pluto, finally, was tucked away by Ithaca's "Sciencenter" a mile or two away (it seemed like billions and billions), a perfect resting place for our favorite dwarf planet (Sciencenter staff said that they would be updating Pluto's factoids to reflect the current controversy). And with the conference over, I could use some rest myself. Ithaca was wonderful. If, as Sagan said, the universe was bigger than anything anyone has dreamed of, then Ithaca was my cozy little solar system for nearly a week. Until next time, Eric.

Posted by Eric Hand on October 15, 2008
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They're still arguing the 'is Pluto a planet' question. I've got to be honest: without much of a stake in the debate (i.e., not being a PI to an icy planet that became a dwarf one) I can't muster that much energy for it. But I'd still be scared of arguing with Hal Levison, who spoke earlier this weekend at a special session on the question.
Hal works at Southwest Research Institute in Colorado, and is an expert on solar system dynamics, and the processes by which little planetesimal pieces coagulate into bigger bodies. He's a big body himself: burly, bearded and boom-voiced, dressed in baggy blue jeans and boots. Eyes flashing, he could be a viking without a helmet. He thinks the whole Pluto debate is kind of absurd. Just look at the distribution, he says. (A nice graphic that Hal refers to, courtesy Cassini scientist John Spencer, after the jump). In the graphic, which shows body size on the y-axis and orbital radius on the x-axis – in logarithmic scale – eight things clearly stand out. They are the planets. Everything else is part of a distribution: asteroids, trojans, KBOs, etc. It's obvious.

Continue reading "AAS DPS 2008: Pluto" »

Posted by Eric Hand on October 14, 2008
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Lots of weather-related Titan talks at this DPS, and it's no surprise, coming from a confluence of maturing Cassini science and an approaching equinox. Titan, which has a year of 30 Earth years, had its summer solstice in 2002. In the next couple years, its north pole will heat up (relatively speaking) as it emerges from winter, and the prevalent methane and ethane lakes will begin to evaporate as clouds form and carry moisture in a giant convective cell that stretches from pole to pole. Pictured here is a Cassini snap from February, with a streaky cloud visible near the north pole: an early sign of spring. “The weather patterns are likely to change fairly rapidly, and that could be quite exciting,” says Ralph Lorenz of Applied Physics Lab in Maryland. The polar lakes grow in winter and shrink in summer, the thinking goes. Ralph points out that sci-fi master Arthur C. Clarke had that same thought back in 1976 in "Imperial Earth". “It was sort of prophetic, in a way,” he says. An excerpt, courtesy Ralph:
The most impressive meteorological phenomenon was the so-called 'Methane Monsoon', which often - though not invariably - occurred with the onset of spring in the northern hemisphere. During the long winter, some of the methane in the atmosphere condensed in local cold spots and formed shallow lakes, up to a thousand kilometers square but seldom more than a few meters deep ...

Posted by Eric Hand on October 14, 2008
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Sometime soon, astronomers are going to announce an Earth-sized extrasolar planet in the habitable zone of its star. And not too long after that, telescopes are going to be able to actually get an image of these things – albeit as a crude, unresolved, disc-averaged blob within a single pixel of the telescope's camera. There are modelers who spend their time thinking about what that blob should look like, and whether its spectroscopic signals would represent something Earth-like. But the models are quirky and need some ground-truthing. They need some Earth-truthing.
And so two current missions, ESA's Venus Express and NASA's EPOXI, a secondary mission for the old Deep Impact spacecraft, are turning their cameras around and taking some fuzzy pictures of Earth. Scientists on the two teams gave talks about the observations over the weekend here. “The crudeness of our observation is really our strength,” says David Grinspoon, astrobiology curator at the Denver Museum of Nature and Science and also a scientist on Venus Express.
This is not first time that Earth has been imaged from afar. In 1990, Voyager 1 took a snapshot of Earth from 4 billion miles away. We are the speck in the middle of the blue circle, pictured here. Carl Sagan used the picture as the inspiration for his book “Pale Blue Dot”. But the Voyager pic and others were one-off, snapshot sort of things. Grinspoon says this is the first time anyone has tried to do good, disc-averaged imaging and spectroscopy on Earth from afar, over time. How does that little blob, and its spectroscopic signature, change with the seasons? With a day, as oceans spin past?
You might think it trivial to calculate this, by just averaging the sum-total of observations from fancy satellites. Turns out that it's very difficult. Ocean and continental signatures are very different; sunlight glints off of oceans in weird ways; atmospheric edge effects are problematic. “Our models are not doing that well right now,” says Tim Livengood of the EPOXI mission. “We have so much information about the Earth, that you have to thin it down to a practical level.”
Both groups, in their 'bad' pictures, found something called the “red edge”, a sudden shelf of brightness in the infrared part of the spectrum caused by plant life. Grinspoon says that a team of Venusian astronomers would thus conclude that Earth indeed has the signature of life.

Posted by Eric Hand on October 13, 2008
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Could a renegade, retrograde ice ball signal a new population of distant bodies in the solar system? Brett Gladman of the University of British Columbia in Vancouver was on hand at a press briefing here to describe his discovery earlier this year of a 50-kilometre chunk of ice that doesn't fit with known populations. It was discovered with a Hawaiian telescope, as a part of a Canadian-French survey of objects beyond the orbit of Neptune. The body, called 2008 KV42, has an orbit that is past perpendicular (104 degrees) to the ecliptic plane of the solar system, and its motion is opposite that of the planets. “That must be due to where it comes from,” says Gladman. The strange orbit has Gladman speculating about a third source of bodies besides the Kuiper Belt and the Oort Cloud. Compositionally, the ice ball fits well with the Kuiper Belt, the ring of Pluto-like ice and rock balls past Neptune, but it's orbit doesn't gibe at all. And while comets from the more distant Oort Cloud have retrograde, highly inclined orbits, this isn't a comet. The team has nicknamed the object Drac, after Dracula, for its ability to walk on walls. Ron Cowen over at Science News has more here.

Posted by Eric Hand on October 13, 2008
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Laura Venner, presenting a poster yesterday, wasn't doing much to dispel stereotypes about New Jersey. Venner is an astronomy educator at the Meadowlands Environment Center in Lyndhurst, New Jersey. She has a new 20-inch telescope that she uses to show schoolchildren binary star systems and all the usual solar system attractions, when the light pollution from New York City isn't too bad. The telescope sits high on a hill -- one that happens to be a rehabilitated sanitary landfill. Of all the rolling hills around her in the Lyndhurst area, she says that only one, called Snake Hill, is real. “All the rest of them are dumps,” she says. “It is very cliché, I know.”

Posted by Eric Hand on October 12, 2008
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Sho Sakada, of Japan's national astronomical observatory, was on hand yesterday to show off the latest results from Kaguya / SELENE, the lunar orbiter launched last year by the Japanese space agency JAXA.
SELENE doesn't have the power that Maria Zuber hopes her GRAIL mission will have. But Sakada showed some of the first high-resolution gravity anomaly maps of the lunar far side, made from radio tracking maps of the surface, as SELENE is tugged ever so slightly up and down by differential gravity. A gravity anomaly map shows where the force of gravity strays from the mean. If there's more mass under you, you weigh more. So standing above a topographic high, or on top of a really dense lode of rock, you'd be slightly heavier: a high gravity anomaly.

What Sakada found was expected: the far side of the moon is full of gravitational lows. Scientists have long thought that the near side cooled more slowly, and that the moon's warm mantle and core were tugged closer to the Earth. This dense rock is much closer to the surface on the near side, as evidenced by the mare basalt flows in all of the basins. The far side has a much thicker crust.

Continue reading "AAS DPS 2008: The moon's thick backside" »

Posted by Eric Hand on October 12, 2008
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What a treat last night. A massive combination of the student symphony orchestras from Cornell and nearby Ithaca College performed Gustav Holtz' “The Planets”, set to an impressive slideshow of planetary images from the last quarter century. I went with my uncle, a space geek who ended up becoming one of Ithaca's orthodonists (he always brags about doing Steve Squyres' kids), and we got two of the last seats in the the balcony of Bailey Hall.

While “The Planets” was thoroughly enjoyably, I was chilled by a special opener, the world premiere of a percussive piece called “Anillos”, Spanish for “Rings”. Music professor Roberto Sierra composed the spooky piece, with its unnerving xylophone swells and timpanic thunder, with images from the Cassini-Huygens mission in mind. It's amazing how visuals can inform your aural experience, and vice versa. I had always thought of Saturn as one of the most regal of planets: the crown prince to Jupiter's king. After “Anillos”, I think of Saturn as the most menacing. The image that sends chills down my spine after the jump: a Cassini pic taken from Saturn's lonely backside, the eclipsed sun nothing but a backlight.

Continue reading "AAS DPS 2008: A symphonic solar system" »

Posted by Eric Hand on October 12, 2008
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Everybody knows about the tiger stripes on Enceladus: the four parallel, long-running 'sulci' or cracks from which plumes of ice and gas spew into Saturn's neighborhood. Now Enceladus has got 'shark fins': raised medial ridges, visible within the tiger stripes. That was the term introduced by Paul Helfenstein of Cornell University, who works on Cassini's main imaging team. “It's turning into a real zoo here,” he says.

He didn't have any new pics from the recent flyby on October 9 (the closest yet), but the team is starting to come up with better explanations for the jumble of faults at the Enceladus' south pole. The shark fins – one of which is the pillowy feature bottom right in the photo – are a feature borrowed from terrestrial geology, when shear and compressive stresses are combined. The oil people call them 'positive flower structures.' The space geeks call them 'shark fins'. Gotta love it. A cartoon explaining the sharks a little more clearly after the jump.

Continue reading "AAS DPS 2008: Tigers and sharks" »

Posted by Eric Hand on October 12, 2008
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Well, I've arrived at the Division for Planetary Sciences meeting of the American Astronomical Society here at Cornell University in Ithaca, New York. And lemme tell you, Ithaca is GORGES. (For those that don't get the town slogan, just navigate the hilly campus for a bit: most traverses of campus involve a suspension bridge or two.)

It's not just pretty terrain but also a pretty time of year: The leaf pundits have us at near peak foliage. The view out over Lake Cayuga, one of New York's finger lakes, is stunning. One can understand why Carl Sagan loved it here. A lovely and fitting place for a planetary science conference. Some 800 other people seem to agree. The lucky 200 that booked years in advance (planetary scientists have a knack for planning long into the future – at least those bound for Pluto) got to stay on site at the Statler Hotel, the Cornell-operated hotel that serves as a something of a classroom for those in Cornell's famous School of Hotel Administration. Onward to the book o' abstracts: 650 of them await...(note to eds: the clock on the library tower reads 8:30 am -- on time for the first session!)

Posted by Eric Hand on October 11, 2008
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First it’s rogue black holes on the loose, now it’s giant gas clouds speeding toward the Milky Way. Astronomers have identified a big glob of hydrogen that’s zooming towards us at more than 150 miles per second – and will hit our galaxy 20 million to 40 million years from now.

Scientists have known about the cloud since 1963, when astronomer Gail Smith identified it before dropping out of research. At the time, no one knew whether the cloud was headed for us, away from us, or something in between.

New observations from the Green Bank radiotelescope – the big dish in the West Virginia mountains that’s surrounded by a zone of cellphone silence, so as not to interfere with the telescope – have pinned down the cloud’s trajectory.

“I’ve been going around calling it the most interesting hydrogen cloud in the known universe,” says Jay Lockman, an astronomer at the National Radio Astronomy Observatory who is also known for his banjo-playing skills. Lockman and his colleagues looked at the cloud nearly 40,000 times with the Green Bank telescope and put together a detailed three-dimensional picture of it.

Right now Smith’s Cloud is about 40,000 light-years from Earth. But when it gets here, it is likely to slam into one of the spiral arms of the Milky Way – fortunately a couple of arms over from the one in which the sun, and you, reside. The collision will probably trigger a burst of star formation – lighting up the local sky in true celestial fireworks.

Lockman said that he was able to reach Gail Smith by telephone just within the past week, to let her know that her discovery of decades ago was literally about to come home. For pictures of where exactly it will hit, check out the NRAO's press release here.

Posted by Alex Witze on January 11, 2008
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Astronomers have gotten pretty worked up lately about what they see as a serious criticism of the way they do business – a paper published last spring by Simon White, director of the Max Planck Institute for Astrophysics in Germany. The paper is called ‘Fundamentalist physics: Why dark energy is bad for astronomy’ and as soon as White started circulating it among the physics and astronomy community, sparks started to fly. (Nature article here, subscription required)

I have to say that I’ve had a hard time getting worked up about the White paper. Basically he’s saying that certain work practices that are common in high-energy physics are threatening the very foundation of astronomy today. These are practices such as creating massive collaborations of coauthors to work on projects, like those needed at detectors at particle accelerators. According to White, astronomy is in danger of moving in the same direction – building giant facilities for doing astronomical research that will consume the creativity of individual scientists. There’s a lot more to his argument than that, but I’d refer you to his paper for the gorey details.

Anyway, last night came a much-ballyhooed ‘debate’ between White and cosmologist Rocky Kolb of the University of Chicago who has written in response to the White work. In my opinion, the debate ended up being a lot of griping about the nature of large collaborations and large facilities, and a lot of worrying about whether young astronomers are being driven away from the field because they don’t want to be the 300th coauthor on a massive paper.

Are you an astronomer? How are important are such working conditions to you? Or do you think creativity will win the day no matter what you’re working on – that there is plenty of good science to be done even under the framework of a massive, faceless machine?

Posted by Alex Witze on January 10, 2008
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Here’s the closest ‘look’ yet at dark matter in a massive galaxy cluster. Dark matter is that stuff that astronomers cannot see but know must exist, because without its gravitational glue to hold galaxies together, they would fly apart into pieces. Naturally, spotting dark matter is a hard thing to do, because it’s, well…invisible.

A team led by Meghan Gray, of the University of Nottingham, and Catherine Heymans, of the University of British Columbia, used gravitational lensing – the same trick described below – to measure how dark matter in space distorts the light from a massive cluster of galaxies known as Abell 901/902. This is a big thing: more than 2.6 billion light-years away, it measures a whopping 16 million light-years across and is composed of more than a thousand galaxies.

The concentrations of pink stuff shows where the dark matter lies. For more images see the main Hubble press release site here.

Posted by Alex Witze on January 10, 2008
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Those intrigued by the question posed in this post,

- What rock group had its members' names included in a reference in the Astrophysical Journal, unbeknownst to the editor?

Continue reading "AAS: Rock'n'Roll'n'ApJ" »

Posted by Oliver Morton on January 10, 2008
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Some talks have titles you just can’t pass up. So it was with “How astronomers die,” a presentation by historian Thomas Hockey of the University of Northern Iowa. Hockey exercised tact in not including perhaps the most famous astronomical death of recent decades, when a young researcher named Marc Aaronson was crushed in 1987 by a rotating observatory dome on Kitt Peak in Arizona. Such modern tragedies aside, Hockey clearly relished the gorey details of astronomers biting the dust in eras long past.

Most astronomers, he told his clearly relieved audience, die natural deaths. But others have gone down in flames in the annals of history – literally. Giordano Bruno, after all, was burned at the stake in 1600, though his crime was heresy, not astronomy. The philosopher Boethius, whose writings covered astronomical topics, was executed by having a cord tightened around his forehead so tightly that his eyes “cracked in their sockets,” says Hockey, and then was bludgeoned to death. And the 4th-century mathematician Hypatia of Alexandria (right) suffered a gruesome death at the hands of Christian mob, who pulled her from her chariot and skinned her alive with oyster shells, as some accounts have it.

War has claimed a fair number of promising astronomers -- from Archimedes who expired via a Roman sword, to British astronomer William Gascoigne, who died at the battle of Marston Moor in Yorkshire in 1644. Travel has also been “quite a grim reaper,” Hockey noted – taking out astronomers in car crashes, shipwrecks, and even a freak blimp accident. Finally, John James Waterston may have actually given his life for his work – while attempting to precisely measure solar radiant energy, he suffered heatstroke that later brought him regular fits of dizziness and may have contributed to his falling, and drowning, in an Edinburgh canal in 1883.

Posted by Alex Witze on January 10, 2008
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Sometimes a picture can be more profound than it looks. This unassuming black-and-white image shows something never seen before – a double ‘Einstein ring’ created by a chance cosmic alignment.

Look closely – you should see not only a bright, nearly circular ring, but also fainter, interrupted arcs of light outside it. That second concentric ring is what makes it a double Einstein ring.

The regular Einstein rings are pretty cool in themselves. They’re optical illusions of a sort, created when light from a distant object (like a galaxy) gets bent by the gravity of a second object that lies along the line of sight between us and the first object. Tommaso Treu, of the University of California Santa Barbara, likens it to holding up a wine glass and looking at a candle through its stem; the distortions in the glass smear out the candle flame into arc-like shapes.

There are only about 50 regular Einstein rings known to date, and Treu and his colleagues were recently hunting for more. And that’s when they stumbled across the double ring. The geometry is complicated: first there’s us; then, 3 billion light-years away, the ‘lens’ which is some object like a massive galaxy; then, 6 billion light-years away, another galaxy whose light has been smeared by the lens to create the inner, bright ring; and finally, 11 billion light-years away, the galaxy whose light has been similarly smeared into the outer, fainter arcs.

It’s a rare alignment, but Treu thinks there may be more out there. Future space missions could potentially spot as many as 50 of the double rings, he says. And with that, astronomers might be able to use the rings to start answering questions about how matter and energy is distributed throughout the universe.

Posted by Alex Witze on January 10, 2008
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It’s almost as startling as 60-year-old women giving birth. Astronomers think they have spotted two stars that are well into middle age and shockingly may still be forming planets around themselves.

Most of the time, planets are born soon after their parent star is. Think of our sun, which in its infancy 4.5 billion years ago also saw planets forming right away, condensing out of the cocoon of dust and gas that swirled around it. You don’t see any newborn planets popping into existence in our solar system today.

But that may be exactly what’s happening at two puzzling stars, says Carl Melis, a graduate student at the University of California, Los Angeles. Despite being well advanced in age, both appear to be surrounded by a dust disk that could be forming planets now. It could, in fact, be a second wave of planetary formation for these stars; the first coming soon after they were born, possibly hundreds of millions of years ago, and the second happening now.

The two stars are odd. One, called BP Piscium in the constellation Pisces (right), was thought to be a young star because of the dusty disk that surrounds it. But studies of its chemical composition and other factors revealed that it is in fact quite old – maybe not to menopause yet, but definitely pushing the limit. The second star, called TYC 4144 392 2 in the constellation Ursa Major, has a dust disk and itself orbits a separate star, which does not have such a disk.

So how did these two old stars end up with dust disks around them? Melis thinks they may have, in the recent past, each swallowed another companion object – something a bit too small to be called a proper star – and, in the digestive process, belched out a giant wave of dust. That dust settled into orbit around the star.

Sara Seager, an expert on extrasolar planets at MIT, says Melis’ idea is plausible. There’s no getting around the fact that these two stars have dust disks, she says. The question now is, how exactly did they get there, and are planets in fact actually forming within them?

Posted by Alex Witze on January 09, 2008
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Stop the presses: Hundreds of rogue black holes are on the loose in the Milky Way!

It’s a good thing that black holes are only dangerous if you’re within about 100 kilometres of them. And the Milky Way is a big enough place that we needn’t worry, says Kelly Holley-Bockelmann, an astronomer at Pennsylvania State University.

Her research team discovered the errant black holes – each of which is 100 to 1,000 times the mass of our sun -- by studying clumps of ancient stars known as globular clusters. These are rough environments, in which black holes are constantly sinking toward the center of the cluster, occasionally meeting in a violet merger that throws one or the other of them out of the cluster at speeds up to 9 million miles per hour. Holley-Bockelmann’s computer simulations show that scientists haven’t spotted nearly as many black holes getting kicked out of globular clusters as one might expect. And so, she says, there must be extra black holes lurking there, invisibly -- some of the biggest rogues ever spotted in our galaxy.

Posted by Alex Witze on January 09, 2008
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I'll be sad to miss the public lecture tomorrow night by Andy Fraknoi, as there is a previously scheduled press event at the same time. But for you science/pop culture buffs out there, see if you can answer some of the questions Fraknoi poses in his abstract:

- In what popular movie does Daryl Hannah play an astronomer? (Answer.)
- What Japanese car company is named after a well-known star cluster? (Answer.)
- What science fiction story, written by an astronomer under a pseudonym, features a Hertzsprung-Russell diagram of stellar evolution? (Answer.)
- Can you recite the most famous neutrino poem, and name the poet? (Answer.)

And here's really geeky one I haven't a clue about - if you know, comment below please!
- What rock group had its members' names included in a reference in the Astrophysical Journal, unbeknownst to the editor?

Posted by Alex Witze on January 08, 2008
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Young stars floating together in isolated gangs, nowhere near adults and asking for trouble. It sounds like the perfect setup for a teen slasher flick, but it’s really a cosmic mystery just discovered 12 million light-years from Earth.

Diulia de Mello, of the Catholic University of America and the Goddard Space Flight Center, and colleagues spotted the stragglers near a smashup of three galaxies (including the well-known pair M81 and M82, right). De Mello calls them “blue blobs”. They are “weird,” she adds – “in regions they are not supposed to be.” That’s because they appear relatively far away from the galaxies, where gas and dust – ingredients generally needed to make stars -- are sparse.

It turns out that the blobs are actually clusters of young stars, born as the galaxies collided with each other over the past 200 million years. The cosmic disruption led to spots locally richer in gas, which then condensed under its own gravity to form newborn stars.

Eventually, the young hoodlums could grow up to throw their own trash into space – by exploding at the ends of their lives and spewing their chemical elements back into intergalactic space. It seems they may never be up to any good.

More details and images are available here.

Posted by Alex Witze on January 08, 2008
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Shuttle schedules willing, astronauts will be going back to the orbiting Hubble Space Telescope this summer. The next and final servicing mission to the telescope (right) is slated for early August, and top NASA brass were out at the astronomy meeting today to tout it.

It’s a far cry from a couple of years ago, when in the wake of the disintegration of the shuttle Columbia NASA’s chief at the time, Sean O’Keefe, cited safety reasons in canceling the final trip to Hubble. That decision prompted an outcry from astronomers and others (Nature story, subscription required) and NASA eventually reversed its decision – after first looking into options to send robots instead of astronauts, and then getting a new administrator in the form of Mike Griffin.

Now the trip is hostage only to delays in shuttle launches; right now, the shuttle is backed up on delivering the European Columbus science module to the international space station, a trip that was supposed to go in December but now looks more likely for February. If other launches continue to slip, an August date for the Hubble mission doesn’t look likely.

No matter – astronomers don’t seem to mind waiting. The next servicing mission will bring two new scientific instruments up to Hubble, plus fix two other ones already up there.

Continue reading "AAS: Return to Hubble" »

Posted by Alex Witze on January 08, 2008
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Join Alexandra Witze at the American Astronomical Society meeting in Austin, Texas from 8-11 January. She'll be sending diary reports back here as astronomers gear up for the International Year of Astronomy in 2009.

Posted by Nicola Jones on January 08, 2008
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Astronomers make startling discoveries in our own back yard.

Astronomers are beginning to realize that we don't know our cosmic neighbourhood very well after all. Some of the galaxies next door to our very own Milky Way are speeding past us so fast that they threaten to rewrite the textbooks, whereas others are so teeny that they may deserve the entirely new name of 'hobbit' galaxies.

Read the story here.

Posted by Nicola Jones on January 10, 2007
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Ever wondered how basketball stars manage to sink a jump shot just-so? John Fontanella, an instructor at the US Naval Academy in Annapolis, Maryland, has the explanation for you.

By comparing videotapes of himself with, er, a slightly more accomplished basketball player, Fontanella calculated that the best players attempt to minimize the speed of the ball when it reaches the basket. That makes intuitive sense, he says - players want a 'soft' shot that sinks right into the basket. But when you hear it described in the context of gravity vs. drag vs. lift vs. buoyance -- well, it's enough to think Shaquille O'Neal might learn enough to improve his free throw percentage.

Posted by Alex Witze on January 10, 2007
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Few scientific presentations really make one hungry (or thirsty), but today's demonstration of the 'hot chocolate effect' did just that.

Tap a spoon on the inside bottom of a mug of hot chocolate, and you'll hear a rising pitch that keeps rising as you keep tapping. It's a fascinating physics experiment that can be done apres-ski. But don't limit yourself to just hot chocolate, says Bradley Carroll of Weber State University in Utah. It works for other beverages, including instant coffee and even cold beer.

It all has to do with tiny bubbles in the liquid. They slow down the speed of sound, so the pitch you hear is lower at first. As the bubbles rise to the surface and break, the speed of sound in the liquid rises, so the pitch rises in tone.

Try it out for yourself. Don't take my word for it.

Posted by Alex Witze on January 10, 2007
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You can say this for intelligent design: It has really inspired the science teachers of America. Today's session on the teaching of intelligent design - the notion that an intelligent 'creator' shaped biological organisms - was jam-packed. In fact, it was so overcrowded that the organizers moved it from a small lecture hall to a section of the giant ballroom.

If science educators such as these get out there and teach kids, one can only think that science will soon triumph over the pseudoscientific arguments of intelligent design.

Posted by Alex Witze on January 10, 2007
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Colliding galaxies in the early Universe produced dance of superbright objects.

Astronomers have found a new record-breaker: a triplet of quasars.

Read about it here.

Posted by Nicola Jones on January 09, 2007
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Here's a new way to reach kids via astronomy: a planetarium in Second Life.

Anthony Crider, an astronomy professor at Elon University in North Carolina, has had his students creating astronomy adventures in the virtual world of Second Life. He set up a planetarium there, and watched 30 to 40 people - their avatars, at least - wait in line for planetarium shows. He has his students test out their class telescope in virtual life before they fumble with it in real life. And he's working with NASA Ames and others to try to create a 'SciLands' area for scientifically interested people to congregate in in Second Life.

Finding like-minded people in the virtual world can be a challenge, though. Crider says he was inspired to purchase his own land and set up a new planetarium after his old location got some new neighbors: a casino, and a shop specializing in lesbian vampire pornography.

Now, though, he sees people coming into Second Life to debate the planetary status of Pluto, or to watch launches of spacecraft on NASA-TV. It's a weird world out there, but there are plenty of astronomy buffs wherever you go.

Posted by Alex Witze on January 09, 2007
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This is fun, if a bit specialized. As seen at a poster here at the AAS meeting: the Slackerpedia Galactica.

It's Wikipedia for astronomy, as you always wished it could be. So far, my favorite entry is the one describing quasars as "vicious little dots".

The entry for Pluto needs a bit of expansion, but shows promise.

Posted by Alex Witze on January 09, 2007
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Wes Traub, of the Jet Propulsion Laboratory in California, reminded the AAS audience today of how an Earth-centric view can help us understand other worlds. Somehow I missed this back in September when it came out - but he and colleagues have done a nifty piece of work looking at Earth's evolution as seen from space. In other words, how has Earth's atmosphere changed composition through time? More specifically, how would aliens looking at Earth interpret life on our planet depending on when they spotted us?

Posted by Alex Witze on January 09, 2007
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The easiest way to guarantee a headline on CNN is to say you've found life on Mars. Or, to be more specific, that NASA once found it but didn't really know it.

At the meeting here today, Dirk Schulze-Makuch of Washington State University described his theory that the Viking landers may have detected signs of microbial Martian life in 1976. The key: hydrogen peroxide, which in addition to bleaching your hair may have formed the basis for alien life forms, he argues.

The problem is that no one has ever been able to agree on what the Viking landers found. One of the key scientists for one of the key instruments has long insisted that it found evidence of life. Few others believe him. So Schultze-Makuch can speculate all day long about life forms based on hydrogen peroxide -- but until someone demonstrates that these kinds of critters really can exist, it'll be awfully tough to prove.

You can read more about the Viking experiments here.

Posted by Alex Witze on January 08, 2007
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Gleaned from astronaut Kathryn Thornton, who flew aboard the space shuttle four times:

If the Earth were the size of a basketball, spacecraft in orbit wouldn't be more than a quarter to a half inch off its surface.

Thornton's point: humans aren't exploring any more. They're stuck repeating experiments in an environment they already know. Most astronauts, of course, are strongly in favor of President Bush's plan to send astronauts back to the moon and then on to Mars. Many scientists are not, which makes her presence at a AAS meeting particularly intriguing.

Posted by Alex Witze on January 07, 2007
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The American Astronomical Society meeting starts here today at the Washington state convention center. They're handing out perhaps the most useful goodies I've ever gotten: a sturdy umbrella. This being Seattle, it is of course raining.

The meeting is joint with the American Association of Physics Teachers, so the usual crowd of typical astronomers is mingling with a younger, more diverse group of educators. As a bonus, the Seattle wedding show is also going on this weekend in the center. So the place is positively buzzing -- I've yet to see any astronomers slinking over to pick up a killer wedding dress, though.

Posted by Alex Witze on January 07, 2007
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Join Alex Witze at the annual meeting of the American Astronomical Society in Seattle from 5-10 January. She'll be blogging about the planets and stars here!

Posted by Nicola Jones on January 05, 2007
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