- Video: The Different Shapes of Iciclology
- Dark Energy and Exoplanets Top List of Astronomy Priorities
- New Titi Monkey Species Discovered In Amazon
- Haiti Quake Occurred on Previously Unknown Fault
- Citizen Scientists Make First Deep Space Discovery With Einstein@Home
- Why Russians Don’t Get Depressed
Posted: 13 Aug 2010 10:35 AM PDT
A team of Canadian iciclologists has put to rest the notion that one frozen cone of drips is exactly the same as the next. By growing lots of icicles in controlled laboratory conditions, the scientists have uncovered evidence that runs counter to an earlier theory saying that all icicles should, by and large, assume the same uniform, Platonic icicle shape. They posted their observations online Aug. 11 at arXiv.org, with a supplementary series of videos on YouTube.
Physicists Stephen Morris and Antony Szu-Han Chen of the University of Toronto set out to test the existing theory's prediction — that most icicles should assume a conical shape. Break off one of these perfect icicles anywhere along its length, and the fragment will be the exact same shape as the whole thing.
"As far as we know, no one has really systematically studied the shape of icicles and how they grow," Morris says. "Nobody has really tried to fill in the physics of how the shape emerges."
To grow icicles, the researchers built a frosty contraption made of a refrigerated box with a water drip at the top. The growing icicles rotated once every four minutes, like a rotisserie chicken, so that on average, the whole surface got the same treatment.
The lab-grown icicles grew to about half-a-meter long, and while some assumed the iconic icicle shape, others came out looking much less than perfect. What's more, the earlier theory posited that growing a perfectly shaped icicle required still air. But Morris and Chen found the opposite in their experiments: Most of the icicles grown in still air sprouted odd little legs at their tips, while those grown in the presence of moving air tended to be more ideally shaped.
Water quality also matters, Morris and Chen found. Icicles grown from distilled water were more likely to be perfectly conical than those grown from tap water, the team found. Tiny impurities in the tap water might be responsible for the lumpy and rippled shapes. "This is Toronto tap water, which is not especially wonderful," Morris says.
Icicles are interesting in their own right (perhaps even more so to Canadians), but studying how they form is important for engineering problems such as ice on airplane wings or power lines. "If you can't understand an icicle, you're not going to understand how ice develops on a fast-blowing airplane wing," Morris says.
Image: A. Szu-Han Chen and S. W. Morris/Experimental Nonlinear Physics/University of Toronto.
Videos: 1) A nearly perfect icicle, created with distilled water in the presence of gently stirred air, forms over the course of about 10 hours. The icicle rotates about once every four minutes./A. Szu-Han Chen and S. W. Morris, Experimental Nonlinear Physics, University of Toronto. 2) An icicle grown with tap water turns bulbous and crooked as it grows in the presence of gently stirred air./A. Szu-Han Chen and S. W. Morris, Experimental Nonlinear Physics, University of Toronto.
Posted: 13 Aug 2010 08:21 AM PDT
Dark energy and extra-solar planet studies received strong endorsement today in a once-a-decade astronomy and astrophysics prioritization report. The National Research Council recommended that the highest priority large-scale projects for the next decade should be the $1.6-billion Wide-Field Infrared Survey Telescope, or WFIRST, and the $465-million Large Synoptic Survey Telescope, or LSST.
The report, titled "New Worlds, New Horizons in Astronomy and Astrophysics," provides recommendations to U.S. funding agencies on the most important astronomy and astrophysics programs that are currently being proposed while accounting for their risks, readiness and costs. Two years in the making, it considered input from a large proportion of the U.S. astronomy community.
Tony Tyson, LSST director, said, "The community, both scientific and the American public, has come together around this notion of surveying the universe in a complete way."
LSST, the top-ranked large ground-based project, would be an 8.4-meter telescope in Chile with a 3-gigapixel camera, able to scan the entire southern sky once every three nights. It would investigate the distributions of visible and dark matter and supernovae throughout the universe and use that to infer details of the structure of the universe through time.
The results would allow scientists to test various theories of dark energy and how it is driving the expansion of the universe. In addition it could watch for near-Earth objects such as asteroids that could pose a risk to Earth in the future.
The top-ranked large space project is the newly named WFIRST, a 1.5-meter telescope that would orbit a point in space called the second Lagrange point, 1.5 million km from Earth. It would investigate dark energy, the poorly understood effect that is causing the universe to expand at an accelerating rate.
The project is based on the previous Joint Dark Energy Mission "Omega" proposal but is expanded to include searches for extra-solar planets. WFIRST would find them by looking for the small deviations in brightness as planetary systems pass in front of distant stars.
The dark-energy community had been split over which of a few competing proposals should go forward, while rising costs and tangles over the relative roles of NASA and the Department of Energy looked like they might doom the project. In October, Jon Morse, director of NASA's astrophysics division, said NASA would wait until it saw the recommendations of this report to assess their position on a dark-energy mission. A proposed 2013 start on WFIRST could enable launch in 2020.
A similar European project called Euclid is competing with other astronomy proposals for a 2017 or 2018 launch slot in the European Space Agency's Cosmic Vision program and the report suggests that collaboration with Europe should be considered.
Astronomers see LSST and WFIRST as complementary approaches to understanding dark energy, although if budgets remain tight, each camp makes arguments for its own superiority in different ways.
Steve Kahn, deputy project director for LSST, said some astronomers have questioned whether a space mission is absolutely necessary to solve the dark energy problem but, "It's what the problem requires. The principle benefit of space is to look into the infrared, which is blocked by the atmosphere. We can combine those results with the LSST visible light observations to reduce the systematic errors which are really limiting our measurements."
The NRC committee emphasized the complementary nature of space and ground missions and also made recommendations about medium- and small-sized projects. The exoplanets theme arose in all sizes of mission.
"The study of exoplanets is of such enormous intellectual importance and it helps us understand our place in the universe," said Louis Friedman, executive director of the Planetary Society.
However, he was cautious about the overall approach. "What's the effect and what's the cost? You never know the trades that will go on once it gets into the bureaucracy."
Friedman sees a strong need for small projects, such as the recommended increase in U.S. participation in Gemini, a pair of twin telescopes in Hawaii and Chile. "Extra support for Gemini might just lead to some discovery that allows you to create a space experiment that makes a definitive discovery of a planet with habitable conditions."
A NASA public affairs official who would only comment anonymously because the agency was still in the process of digesting the report said, "There are a few differences between what we are doing and what is in the report."
He said that because the FY11 budget was already locked in place that NASA would need to work through the recommendations to see what was possible. The agencies involved will get together in the next few weeks to look at their plans in light of the report.
With considerable pressure on the government to reduce spending, there is always a question of whether basic science research will be cut in favor of shorter term priorities.
"This is a challenging time for anywhere in the world," Tyson said. "But if there is a will there will be money found. I think there is a will."
Image: Artist's rendering of he LSST, a proposed 8.4-meter ground-based telescope that will survey the entire visible sky deeply in multiple colors every week from a mountaintop in Chile. LSST Corporation / NOAO)
Posted: 13 Aug 2010 12:19 AM PDT
A newly discovered species of titi monkey purrs like a cat and looks like a leprechaun.
Although it was first spotted in 1976 by biologist Martin Moynihan in the southern Caqueta province of Colombia, frequent armed conflict in the region has prevented scientists from being able to confirm its existence until now.
The new species, named the Caqueta titi monkey or Callicebus caquetensis, is one of about 20 species of titi monkeys, which all live in the Amazon basin, according to primatologist Thomas Defler, who led the expedition that made the discovery announced Aug. 12 in Primate Conservation.
"The titi monkey genus is so speciose that it is likely there are many species that we don't know now," Defler added.
The Caqueta titi monkey is being recommended for classification as Critically Endangered. The population size has been estimated at less than 250 individuals, and its habitat has been fragmented by clearing for agricultural land.
Titi monkeys are one of the only species of primate that are monogamous, gibbons being one of the only other ones.
"Even human beings aren't all that monogamous," Defler said.
Defler raised a couple titi monkeys once, and says that their monogamous behavior causes them to be endearing. He called one of their behaviors "space saving," where they encourage the other monkey to get closer to them.
"All of the babies purr like cats too," Defler added. "When they feel very content they purr towards each other, and the ones we raised would purr to us."
After years of wanting to go to the Caqueta region to search for the monkey, Defler was finally able to go in part because of a new government that has made the region safer, and in part because he met a biology student named Javier Garcia who was from the region, which also made it safer for them to go, Defler said. Conservation International provided funding for the project.
They spotted the monkey just a few days after they arrived in the region in August 2008. They returned to the region in 2009 to study the distribution of the species.
Defler hopes that the discovery will help lead to the creation of new preserves for the monkey. Garcia also plans to study the monkey for his master's degree.
Images: 1) Javier Garcia. 2) Illustration by Stephen Nash. 3) Javier Garcia. 4) Thomas Defler.
Posted: 12 Aug 2010 01:09 PM PDT
IGUAÇÚ FALLS, Brazil — The devastating quake that slammed Haiti on Jan. 12 occurred on a previously unrecognized fault zone, report scientists who are still trying to determine the implications for the region's long-term seismic risk.
The newly discovered fault hasn't been officially named yet but is informally known as the Léogane fault, after one of the Haitian cities that sits directly atop it, study leader Eric Calais told Science News.
Just after the magnitude-7 temblor struck, scientists presumed that the epicenter of the quake was located on the well-known Enriquillo fault, says Calais, a geophysicist at Purdue University in West Lafayette, Indiana. In fact, Calais notes, he and his colleagues published a paper in 2008 suggesting that the Enriquillo fault, which runs east-west through a long valley south of Port-au-Prince, Haiti, was ripe for a magnitude-7.2 quake.
But data collected after the quake didn't jibe with the notion of an Enriquillo-spawned quake, Calais reported Aug. 10 at a geophysics conference called the Meeting of the Americas. For one thing, the edges of that fault are vertical and the two sides slide past each other horizontally, but comparisons of space-based images taken before and after the quake revealed that the area north of the fault had been forced substantially upward, as well as southward, during the event. During a post-quake field survey along the coastline west of Port-au-Prince, scientists also found that formerly submerged corals died when the quake lifted them above the tides by as much as 60 centimeters.
Altogether, this data points to a different culprit and suggest that this previously unknown fault is about 30 kilometers long, says Calais. Unlike the Enriquillo fault, which extends vertically into the ground, the newly discovered fault dips steeply northward into the earth at an angle of about 60 degrees.
"This is part of a whole system of faults that we hadn't recognized before," Calais notes. The fault had escaped detection largely because Haiti has no network of seismometers, and the neighboring Dominican Republic has only a few such instruments.
During the January quake, deep parts of the Léogane fault slipped past each other as much as 5 meters. Despite the significant slippage that occurred at depths between 5 and 20 kilometers, there was — unusually, Calais says — no rupture of the ground at Earth's surface.
Posted: 12 Aug 2010 12:40 PM PDT
While your computer is running idle, it could be finding new pulsars and black holes in deep space.
Three volunteers running the distributed computing program Einstein@Home have discovered a new pulsar in the data from the Arecibo Observatory radio telescope. Their computers, one in Iowa (owned by two people) and one in Germany, downloaded and processed the data that found the pulsar, which is in the Milky Way, approximately 17,000 light years from Earth inconstellationVulpecula.
"The way that we found the pulsar using distributed computing with volunteers is a new paradigm that we're going to make better use of in astronomy as time goes on," said astronomer Jim Cordes of Cornell University. "This really has legs."
About 250,000 volunteers run Einstein@Home, on average donating about 250 teraflops of computing power — equivalent to a quarter of the capacity of the largest supercomputer in the world, says program developer David Anderson ofUniversityofCalifornia at Berkeley's Space SciencesLaboratory, co-author of the Aug. 12 discovery announcement in Science.
Einstein@Home has been searching for gravitational waves in the data from the US LIGO Observatory since 2005, and since March 2009 has dedicated one-third of its power to searching for radio pulsars and black holes in the Arecibo data. As of this week, it will start dedicating half of its processing power to data from Arecibo, the world's largest and most sensitive radio telescope, physicist Bruce Allen of the Max Plank Institute for Gravitational Physics in Germany and co-author of the study announced a press conference Aug. 12.
The new pulsar, dubbed PSR J2007+2722, is a neutron star rotating 41 times per second. Pulsars are birthed when stars five to 10 times as massive as our sun explode into a supernova and then collapse into stars composed almost entirely of neutrons.
The data from Arecibo was processed on the computer in Iowa June 11, and then also processed on a computer in Germany June 14 for validation. The finding was part of a larger search that returned results on July 10, which was the first time a human being was aware of the discovery.
The person who looked at the results notified Greenbank Observatory in West Virginia, which immediately pointed their telescope at the new pulsar to verify it. Within hours, Arecibo Observatory in Puerto Rico also pointed their telescope at it.
"This is the first time I've worked closely with radio astronomers making a discovery," said Allen. "It was like watching 5-year-olds tearing Christmas presents. Or likewatchingsomeone throw chunks of meat at starving sharks."
Pulsars are named after the pulsing signals they send to Earth. The pulse comes from the spin and the magnetic field of the neutron star being on two different axes, which acts like an electric generator and creates a beamed signal that rotates like a lighthouse. Cordes says theoretical predictions are that only about 20 percent of the pulsars in the galaxy are detectable on Earth because the beam needs to point directly at us to be detected.
Often, pulsars have a companion star or neutron star that was originally born in the same cloud of gas. But this new pulsar doesn't and is likely a disrupted recycled pulsar. This means the pulsar once had a companion star that it sucked matter from as the star swelled up into a red giant, which caused the pulsar to cycle faster (recycle). The red giant star then exploded into a supernova and blasted the pulsar away, leaving it alone in space (disrupted).
The new pulsar is one of around 2000 pulsars that have been discovered using radio telescopes in the past 43 years, said Cordes. He estimates there are 20,000 pulsars in the Milky Way that could be detected.
"I see this as a long-term effort where we're going to find really interesting objects," said Cordes. "We'd like to find a pulsar orbiting a black hole, or a pulsar orbiting another neutron star so that we can test some of Einstein's predictions of the general theory of relativity"
You can become part of the effort by downloading BOINC. The program has been used to create 70 different distributed computing projects (almost every one in existence except Folding@Home), and you can decide what fraction of your spare computing power you want to dedicate to each of the 70 projects.
In case you need more incentive, Cordes announced that a second pulsar has been already been discovered in the last month by Einstein@Home users in the United Kingdom and Russia. He's keeping details to himself for now.
"We have a very large data set," Cordes added at the press conference. "We just need to cull through it, and Einstein@Home lets us use a much finer comb."
Images: 1) Screen shot of Einstein@Home/B. Knispel, Albert Einstein Institute. 2) Copyright Cornell University.
Posted: 12 Aug 2010 11:50 AM PDT
The saddest short story I've ever read is "The Overcoat," by Gogol. (It starts out bleak and only gets bleaker.) The second saddest story is "Grief," by Chekhov. (Nabokov famously said that Chekhov wrote "sad books for humorous people; that is, only a reader with a sense of humor can really appreciate their sadness.")And then, if I had to make a list of really depressing fiction, I'd probably put everything written by Dostoyevsky. Those narratives never end well.
Notice a theme? Russians write some seriously sad stuff. This has led to the cultural cliche of Russians as a brooding people, immersed in gloomy moods and existential despair. In a new paper in Psychological Science, Igor Grossmann and Ethan Kross of the University of Michigan summarize this stereotype:
This cliche raises two questions. Firstly, is it true? And if it is true, then what are the psychological implications of thinking so many sad thoughts?
The first experiment was straightforward. The psychologists gave subjects in Moscow and Michigan a series of vignettes that described a protagonist who either does or does not analyze her feelings when she is upset. After reading the short stories, the students were then asked to choose the protagonist that most closely resembled their own coping tendencies. The results were clear: While the American undergraduates were evenly divided between people who engaged in self-analysis (the brooders) and those who didn't, the Russian students were overwhelmingly self-analytical. (Eighty-three Russians read the vignettes; sixty-eight of them identified with the brooders.) In other words, the cliche is true: Russians are ruminators. They are obsessed with their problems.
At first glance, this data would seem like really bad news for Russian mental health. It's long been recognized, for instance, that the tendency to ruminate on one's problems is closely correlated with depression. (The verb is derived from the Latin word for "chewed over," which describes the process of digestion in cattle, in which they swallow, regurgitate and then rechew their food.) The mental version of rumination has a darker side, as it leads people to fixate on their flaws and mistakes, preoccupied with their problems. What separates depression from ordinary sadness is the intensity of these ruminations, and the tendency of depressed subjects to get stuck in a recursive loop of negativity.
According to Grossman and Kross, however, notall brooders and ruminators are created equal. While American brooders showed extremely high levels of depressive symptomatology (as measured by the Beck Depression Inventory, or BDI), Russian brooders were actually less likely to be depressed than non-brooders. This suggests that brooding, or ruminative self-reflection, has extremely different psychiatric outcomes depending on the culture. While rumination makes Americans depressed, it actually seems to provide an emotional buffer for Russians.
What explains these cultural differences? Grossman and Krossthen asked students in Moscow and Michigan to "recall and analyze their "deepest thoughts and feelings surrounding a recent anger-related interpersonal experience". Then, the subjects were quizzed about the details of their self-analysis. They were asked to rate, on a seven point scale, the extent to which they adopted a self-immersed perspective (a 1 rating meant that they "saw the event replay through your own eyes as if you were right there") versus a self- distanced perspective (a 7 rating meant that they "watched the event unfold as an observer, in which you could see yourself from afar"). Finally, the subjects were asked about how the exercise made them feel. Did they get angry again when they recalled the "anger-related" experience? Did the memory trigger intense emotions?
Here's where the cultural differences became clear.* When Russians engaged in brooding self-analysis, they were much more likely to engage in self-distancing, or looking at the past experience from the detached perspective of someone else. Instead of reliving their confused and visceral feelings, they reinterpreted the negative memory , which helped them make sense of it. According to the researchers, this led to significantly less "emotional distress" among the Russian subjects. (It also made them less likely to blame another person for the event.) Furthermore, the habit of self-distancing seemed to explain the striking differences in depressive symptoms between Russian and Americans. Brooding wasn't the problem. Instead, it was brooding without self-distance. Here's Grossman and Kross:
The lesson is clear: If you're going to brood, then brood like a Russian. Just remember to go easy on the vodka.
*I think cross-cultural studies like this are an important reminder than American undergrads are W.E.I.R.D.
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