Day: 01/12/2012

Astronomers release unprecedented data set on celestial objects that brighten and dim.

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Astronomers from the California Institute of Technology (Caltech) and the University of Arizona have released the largest data set ever collected that documents the brightening and dimming of stars and other celestial objects—two hundred million in total.

 

The night sky is filled with objects like asteroids that dash across the sky and others—like exploding stars and variable stars—that flash, dim, and brighten. Studying such phenomena can help astronomers better understand the evolution of stars, massive black holes in the centers of galaxies, and the structure of the Milky Way. These types of objects were also essential for the recent discovery of dark energy—the mysterious energy that dominates the expansion of the universe—which earned last year’s Nobel Prize.

Using the Catalina Real-Time Transient Survey (CRTS), a project led by Caltech, the astronomers systematically scanned the heavens for these dynamic objects, producing an unprecedented data set that will allow scientists worldwide to pursue new research.

“Exploring variable objects and transient phenomena like stellar explosions is one of the most vibrant and growing research areas in astrophysics,” says S. George Djorgovski, professor of astronomy at Caltech and principal investigator on the CRTS. “In many cases, this yields unique information needed to understand these objects.”

The new data set is based on observations taken with the 0.7-meter telescope on Mt. Bigelow in Arizona. The observations were part of the Catalina Sky Survey (CSS), a search for Near-Earth Objects (NEOs)—asteroids that may pose a threat to Earth—conducted by astronomers at the University of Arizona. By repeatedly taking pictures of large swaths of the sky and comparing these images to previous ones, the CRTS is able to monitor the brightness of about half a billion objects, allowing it to search for those that dramatically brighten or dim. In this way, the CRTS team identified tens of thousands of variables, maximizing the science that can be gleaned from the original data.

The new data set contains the so-called brightness histories of a total of two hundred million stars and other objects, incorporating over 20 billion independent measurements. “This set of objects is an order of magnitude larger than the largest previously available data sets of their kind,” says Andrew Drake, a staff scientist at Caltech and lead author on a poster to be presented at the meeting of the American Astronomical Society in Austin on January 12. “It will enable many interesting studies by the entire astronomical community.”

One of the unique features of the survey, Drake says, is that it emphasizes an open-data philosophy. “We discover transient events and publish them electronically in real time, so that anyone can follow them and make additional discoveries,” he explains.

“It is a good example of scientific-data sharing and reuse,” Djorgovski says. “We hope to set an example of how data-intensive science should be done in the 21st century.”

The data set includes over a thousand exploding stars called supernovae, including many unusual and novel types, as well as hundreds of so-called cataclysmic variables, which are pairs of stars in which one spills matter onto another, called a white dwarf; tens of thousands of other variable stars; and dwarf novae, which are binary stars that dramatically change in brightness.

“We take hundreds of images every night from each of our telescopes as we search for hazardous asteroids,” adds Edward Beshore, principal investigator of the University of Arizona’s asteroid-hunting CSS. “As far back as 2005, we were asking if this data could be useful to the community of astronomers. We are delighted that we could forge this partnership. In my estimation, it has been a great success and is a superb example of finding ways to get greater value from taxpayers’ investments in basic science.”

The team says they soon plan to release additional data taken with a 1.5-meter telescope on Mt. Lemmon in Arizona and a 0.5-meter telescope in Siding Spring in Australia.

Source:California Institute of Technology

 

Over 160 bn alien planets may exist in Milky Way.

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Alien planets are incredibly common in our own galaxy Milky Way and it may be having as many as 160 billion planets, a six-year-long study has suggested.

According to the study, published in the journal Nature, there are over 100 billion stars in our galaxy and each of them hosts at least 1.6 planets on average, bringing the number of likely alien worlds to more than 160 billion.

And large numbers of these exoplanets are likely to be small and rocky, roughly like Earth, since low—mass planets appear to be much more abundant than large ones, it claimed.

“This statistical study tells us that planets around stars are the rule, rather than the exception,” said study author Arnaud Cassan of the Paris Institute of Astrophysics.

“From now on, we should see our galaxy populated not only with billions of bright stars, but imagine them surrounded by as many hidden extra solar worlds,” Cassan told SPACE.com.

Till date, astronomers have discovered over 700 planets beyond our own solar system, with 2,300 “candidates” found by NASA’s Kepler space telescope awaiting confirmation.

In the new study, the researchers looked at data gathered by a variety of Earth-based telescopes, which scanned millions of stars from 2002 to 2007 for microlensing events.

The team closely analysed about 40 of these events and discovered that three betrayed the presence of an alien planet around a star. One of these planets is a bit more massive than Jupiter, one is comparable to Neptune and the third is a so-called “super-Earth” with a mass about five times that of our home planet.

Considering how perfectly aligned multiple bodies must be to yield an exoplanet detection via microlensing, that’s a pretty impressive haul, researchers said.

The astronomers used all of this data and information about seven additional planets detected by other microlensing efforts, to put a number on their planet-detection efficiency — and, by extension, the number of alien worlds that may populate the Milky Way.

The team determined that about one-sixth of our galaxy’s stars harbour Jupiter-mass planets, half have Neptune-like worlds, and nearly two-thirds host super-Earths.

And that’s just in the stretch of orbital space from 0.5 to 10 astronomical units — distance from Earth to the sun — from each star, the limit of the study’s sensitivity.

“Moreover, we confirm that low-mass planets, such as super-Earths (up to 10 Earths) and Neptune-like planets are much more abundant than giant planets such as Saturn and Jupiter (with estimates that there are six to seven times more low-mass than giant planets),” Cassan said.

Further, according to the researchers’ calculations, every planet in the Milky Way harbours an average of 1.6 planets in the 0.5-10 AU range, which in our solar system corresponds roughly to the swath of space between Venus and Saturn.

Since astronomers estimate that our galaxy contains about 100 billion stars, that works out to at least 160 billion alien planets.

However, the true number of alien worlds may be quite a bit larger than 160 billion, as some planets hug their host stars more closely than 0.5 AU, and others are more far-flung than 10 AU. And a great many likely have no host star at all, the researchers added.

Source:Nature

Hemp Seeds: The Most Nutritionally Complete Food Source In The World!

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Hemp Seeds, are the most nutritionally complete food source in the world! Hemp has been eaten for thousands of years in different parts of the world. It’s the seed that we eat, and it’s beneficial in terms of protein and essential fatty acids. There’s evidence that goes back thousands of years that it was being eaten in China and in different places around the world for there health benefits.

Hemp seeds have an astonishing balanced nutritional make-up. It is one of the plant kingdom’s most concentrated, complete and balanced sources of all 10 essential amino acids (EAA’s) and essential fatty acids (EFA’s) which are necessary to maintain healthy human life. You can divide it roughly into three components.

First: There are the essential fatty acids in the oil — omega-6, omega-3, omega-9 — and also minor fatty acids like gamma linolenic acid (GLA) and stearidonic acid, which is biosynthesized from the alpha-linolenic acid (ALA).

 

GLA and ALA cannot be made by the human body and must be obtained through the diet, so they are called essential fatty acids (EFA). GLA and ALA are the most important fatty acids in human nutrition and health. They are involved in producing life energy from food and the movement of that energy throughout the body. EFAs govern growth, vitality and state of mind. Still, much is unknown about their functioning in the body. This oil comprises 35% of the total seed weight and has the lowest amount of saturated fatty acids at 8%, and the highest amount of the polyunsaturated essential fatty acids at 80%. Flax seed oil comes in second at 72% combined total essential fatty acids.

Second: 35% consists mostly of fiber, both soluble and insoluble. Insoluble fiber possesses passive water-attracting properties that help to increase bulk, soften stool and shorten transit time through the intestinal tract. Soluble fiber undergoes metabolic processing via fermentation, yielding end-products with broad, significant health effects.

Thirdly: 25% consists of a complete and highly-digestible protein, 65% high-quality edestin protein, the most potent protein of any plant source, 35% albumin protein and glutamic acid. The globulin edestin in hemp seed closely resembles the globulin in blood plasma, and is compatible with the human digestive system. It is vital to the maintance of a healthy immune system and is also used to manufacture antibodies. Albumin is a protein manufactured by the liver that is supportive of liver and kidney health. Its high quality amino acid composition is closer to “complete” sources of proteins (meat, milk, eggs) than all other oil seeds except quinoa and soy.

Hemp seeds are also high in essential nutrients including chlorophyll, magnesium, potassium, sulfur, phytosterols, ascorbic acid, beta-carotene, calcium, fiber, histidine, iron, potassium, phosphorus, riboflavin, niacin and thiamin.

Omega 3 to Omega 6 Ratio:

A variety of studies have documented the importance of the ratio of Omega 3 to Omega 6 consumption. Hemp seed oil is the closest to this optimum ratio of any naturally occurring oil. Hemp seed oil has a ratio of at least one-to-three, Omega 3 to Omega 6. Oils with unbalanced ratios have been shown to have detrimental physiological effects.

My Thoughts:

I love hemp seeds and my favorite product is ‘Organic Shelled Hemp Seeds‘ from Nutiva. Hemp seeds have a great nutty flavor with a variety of uses. Nutiva uses the finest certified organic ingredients, there organic seeds are grown without any chemical pesticides, herbicides or chemical fertilizers and there not genetically modified–safer for you and the planet. There products are certified by Quality Assurance International(QAI)-which is a USDA authorized organic certifier.

Another great way to get the health benefits of hemp seeds is to purchase, ‘Cold-Pressed Hemp Seed Oil‘, which is nutritionally superior to olive or flax oil, and so, makes a great alternative in salads, smoothies, and other non-frying uses.

It should be noted that you can also purchase ‘whole hemp seeds’ that are not ‘hulled’ (outer shell removed). They are a bit harder to find at your local grocery store, but there are lots of places on the internet where you can buy them. Whole hemp seeds are an excellent source of minerals and much more stable out in the air then hulled seed. However Nutiva takes great care in processing and packaging there ‘hulled’ hemp seeds creating maximum nutritional potential. I have recently ordered ‘whole hemp seeds’ from several manufactures and will be writing a future article on the best place to find them.

On a separate note: I highly recommend everyone reading this, to watch a documentary called: Emperor of Hemp by Jack Herer. You will be amazed at how hemp fiber could revolutionize the world we live in, but as always the harvesting of hemp is outlawed to protect ‘Big Corporation’ from massive profit loss. All of which is truly at the expense of our planet.

How To Eat Hemp Seeds:

Incorporating hemp seeds in your diet is so easy. You can purchase whole hemp seeds, hulled hemp seeds, hemp seed protein powder, and hemp seed oil. Simply just eat them raw, add them to a salad, replace olive oil with hemp seed oil, etc. I add 2 tbs of Hemp Seeds everyday to my ‘health shake’. Post a comment below and tell us how you use hemp seeds!

Remember it’s best to keep hemp seeds refrigerated and air tight. If you purchase a bulk 5-pound bag, consider adding a pound to a container for daily use, and seal up the 5-pound bag and place it in the freezer. This will help protect the seed and the nourishing Omega-3s which are sensitive to heat and oxygen.

Where To Buy Hemp Seeds:

You can buy them at Whole Foods and many grocery and health stores, there usually located in the vitamin department. I personally buy them online at www.Nutiva.com. Some grocery and health food stores have hemp seeds in the ‘dry bin’ section. The only reservation I have about this, is hemp seeds should be stored in a dark, sealed, air tight container and then kept at a cool temperature to preserve the nourishing Omega-3s which are sensitive to heat and oxygen, With the ‘dry bins’ you don’t know where the hemp seeds came from, how long they have been there and they’re usually not sealed, in a cool place or certified organic.

Source:Organic Jar Blog.

 

Diabetes Medications May Double as Weight Loss Drugs.

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Research Review Shows Byetta and Victoza Can Help Overweight People Shed Pounds

Two drugs approved to treat type 2 diabetes may also aid weight loss in overweight people with or without diabetes, a new study shows.

The drugs Byetta and Victoza mimic gut hormones that decrease appetite.

They are typically prescribed when patients need medication to help control their blood sugar. A new research review, published in BMJ, reanalyzed data from 25 separate studies.

The review reveals that the drugs helped overweight people without diabetes shed an average of 7 pounds and those with diabetes lose an average of 6 pounds when injected daily or weekly for at least five months.

That makes these agents promising treatments for obesity, study authors say.

“It’s not a cure, but it’s a good treatment. And you still need to combine it with lifestyle changes,” says researcher Tina Vilsboll, MD, DMSc, an endocrinologist and associate professor at Gentofte Hospital in Hellerup, Denmark.

Vilsboll says the modest weight loss many of her diabetic patients see on the drugs helps encourage them to kick up their diet and exercise programs to lose even more weight.

“They use it as a tool for changing their lifestyle,” she says.

Weighing Risks and Benefits

The medications also appear to lower blood pressure and cholesterol slightly, which may help heart disease risks.

But the drugs, known as glucagon-like peptide-1 (GLP-1) receptor agonists, also come with side effects. They work, in part, by slowing the movement of food through the stomach. That can sometimes cause a good deal of nausea or even vomiting, especially after a large meal.

But Vilsboll says that side effect generally fades over time and doesn’t usually cause people to stop taking the medication.

Experts who were not involved in the review say they are cautiously optimistic about the drugs’ prospects for weight loss.

“We do have an obesity epidemic. Weight loss by traditional means — diet and exercise — is extremely hard, and for people who are successful initially, it’s also very hard to maintain,” says Susan Spratt, MD, an endocrinologist and the director of diabetes services at Duke University Health System in Durham, N.C.

“If we could use these drugs just in people with obesity and know that it’s safe, I think it would be a fantastic addition to our ability to treat obesity,” Spratt says.

“I’ve had [diabetic] patients lose 60 pounds with these medications. Now, those folks were 400 pounds, so they lost 10% to 15% of their body weight,” she says. “Somebody who’s 200 pounds isn’t going to lose that much.”

Drugs Can Be Used Already, but Should They?

Because the drugs are already on the market, doctors have the ability to prescribe them solely for weight loss.

But experts say such “off-label” use of the drugs can be risky.

“Off-label use happens quite a bit, actually, for obesity drugs because people are so desperate to try something,” says Raj Padwal, MD, an associate professor of internal medicine at the Walter C. Mackenzie Health Sciences Centre in Edmonton, Alberta, Canada.

Large studies testing the drugs for weight loss in people without diabetes are ongoing.

Until the results of those studies are known, “I think the off-label use of these agents would be premature,” Padwal tells WebMD.

He says Byetta and Victoza are already known to be associated with uncommon but potentially serious health risks.

In 2009, the FDA warned doctors about the possibility of kidney problems in patients taking Byetta.

Last June, the FDA sent a letter to doctors reminding them to keep a close eye on patients taking Victoza. In animal studies, the use of Victoza was associated with an increase of certain thyroid cancers. And in clinical trials, people taking the drug had more cases of pancreatitis than people who got other kinds of diabetes medications. “We don’t know the long-term safety, and that is a huge concern,” Spratt says.

Cost is another concern. Without insurance, Padwal says Byetta and Victoza can cost $300 to $500 for a month’s supply. “Given that cost, you kind of want to stick to the indications for the drug, which right now are sugar control in diabetes,” he says.

Source:Medicine.net

Improvement in Survival of Older Adults with Multiple Myeloma: Results of an Updated Period Analysis of SEER Data.

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Treatment of multiple myeloma has changed significantly over the past several years with clinical trials reporting superior survival results using newer agents. Previous work has shown that the survival rate has improved for younger, but not older, patients with myeloma. Here, we update survival estimates for patients with myeloma in the early 21st century to determine whether continued improvement can be seen on a population level and whether or not it now extends to older patients.

Methods. Using period analysis to examine data from the Surveillance, Epidemiology, and End Results database, we estimate changes in the 5- and 10-year relative survival rates (RSRs) from 1998–2002 to 2003–2007.

Results. The 5- and 10-year RSRs have improved for patients with myeloma overall, from 32.8% and 15% in 1998–2002 to 40.3% and 20.8%, respectively, in 2003–2007. The greatest improvements were observed for patients aged 15–44 years, with 5- and 10-year RSRs reaching >70% and ∼50%, respectively, but improvements were also seen for patients aged >70 years.

Conclusion. Overall, survival continues to improve for patients with myeloma, including older patients, suggesting that newer treatment options continue to make a population-wide impact.

Source:The Oncologist.

The First Oxygen Users?

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None of us would be here today if, billions of years ago, a tiny, single-celled organism hadn’t started using oxygen to make a living. Researchers don’t know exactly when this happened, or why, but a team of scientists has come closer than ever before to finding out. They’ve identified the earliest known example of aerobic metabolism, the process of using oxygen as fuel. The discovery may even provide clues as to where the oxygen came from in the first place.

To travel so far back in time, evolutionary bioinformaticist Gustavo Caetano-Anollés of the University of Illinois, Urbana-Champaign, along with colleagues in China and South Korea, did a bit of molecular sleuthing. They scoured published genomes from all groups of organisms-although they didn’t include viruses in this study-focusing on pieces of proteins known as domains. These pieces have their own distinguishing shapes that provide clues to the protein’s function and can be categorized based on various characteristics. Just like a Victorian house has certain features that set it apart from a Tudor mansion, researchers can tell the difference between different domains based on their shape.

Over time, proteins with multiple domains can switch them in and out like Lego blocks, Caetano-Anollés says. This is problematic because the shuffling can obscure the evolutionary origin of a domain. So his group analyzed only proteins with one domain that encoded one function. The researchers hoped that by limiting their study to domains that were involved in aerobic metabolism, they could trace the history of the process.

The team produced a kind of molecular clock by establishing an evolutionary sequence for single-domain proteins. Caetano-Anollés and his colleagues could then tie that sequence to the geologic timeline. By correlating the appearance of domains integral to events such as the rise of eukaryotes, organisms with membrane-bound cellular structures, they could determine an approximate date for the origin of particular domains. “Molecular clocks aren’t perfect,” Caetano-Anollés acknowledges. “And sometimes they misbehave. But the [domains] that we sampled that were linked to clear-cut events had good agreement.”

The researchers found that the most ancient aerobic process was the production of pyridoxal, or the active form of vitamin B6, they report today in Structure. This reaction appeared about 2.9 billion years ago, along with an oxygen-producing enzyme called manganese catalase. This enzyme detoxifies hydrogen peroxide by breaking it down into water and oxygen. Caetano-Anollés hypothesizes that early organisms got the oxygen they needed to produce vitamin B6 from this breakup of hydrogen peroxide. The authors argue that these ancient organisms would have encountered massive amounts of hydrogen peroxide in their environment due to the bombardment of glacial ice by ultraviolet radiation, which can generate the compound.

“It’s a great paper in terms of the evolution of protein [domains],” says Paul Falkowski, an evolutionary biogeochemist at Rutgers University in New Brunswick, New Jersey, who wasn’t involved in the study. But Timothy Lyons, a biogeochemist at the University of California, Riverside, is skeptical that high levels of hydrogen peroxide were produced by glaciers. “There is little direct evidence for a hydrogen peroxide spike at this time,” he says. Still, he says the study is a compelling effort at pinpointing the evolutionary origin of aerobic metabolism.

Source:Science.

 

 

Battery, heal thyself: Inventing self-repairing batteries.

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A team of researchers from the University of Illinois at Urbana-Champaign (UIUC) and the U.S. Department of Energy’s (DOE) Argonne National Laboratory are exploring ways to design batteries that heal themselves when damaged.

“This would help electronics survive daily use—both the long-term damage caused by charging over and over again, and also the inevitable physical damage of everyday life,” said Jeff Moore, a UIUC scientist on the team.

Scientists think that loss of electrical conductivity is what causes a battery to fade and die. Theories abound on the specific molecular failures; perhaps chemicals build up on electrodes, or the electrodes themselves pull away. Perhaps it’s simply the inevitable stress fractures in materials forced to expand and contract repeatedly as the battery is charged and used.

In any case, the battery’s storage capacity drops due to loss of electrical conductivity. This is what the team wants to address.

The idea is to station a team of “emergency repairmen” already contained in the battery. These are tiny microspheres, each smaller than a single red blood cell, and containing liquid metal inside. Added along with the battery components, they lie dormant for most of the battery’s lifetime.

But if the battery is damaged, the capsules burst open and release their liquid metal into the battery. The metal fills in the gaps in the electrical circuit, connecting the broken lines, and power is restored.

Capsules could be designed to be triggered by different events—some that respond to physical damage and others that respond to overheating, for example. This would allow scientists to tailor the contents of the different capsules to repair specific situations.

Microcapsules have been manufactured in large scale since the 1950s. When you press your pencil down on carbonless copy paper, microcapsules full of ink burst open to leave an imprint on the paper layers beneath. Microcapsules full of perfume burst when you rub a scratch-and-stiff sticker.

“We hope that using microcapsules, which are a well-known technology, could make this technology easy to scale up for commercial use,” Moore said.

The team’s first step was to test the system in a simple system, connecting an electrode with a wire to see if the capsules could “heal” the circuit if cut. (Watch a demonstration of this in the video above).

“Our new self-healing materials can completely repair the circuit in less than a millisecond,” Moore said.

The next step, which the researchers are beginning, is to test the capsules in a prototype battery. Argonne materials scientist and battery expert Khalil Amine is helping the team adapt the capsules for lithium-ion batteries. Other collaborators are UIUC scientists Nancy Sottos and Scott White.

The work is funded through the Center for Electrical Energy Storage (CEES), one of three Argonne-led Energy Frontier Research Centers (EFRCs). Established in 2009 by a special block grant from DOE, the EFRCs are five-year interdisciplinary programs focused around specific scientific challenges that are believed to be key to breakthroughs in energy technology.

The CEES is addressing the problems that limit electrochemical energy storage technologies—such as batteries and supercapacitors—for transportation, residential and commercial use.

 

Source: Argonne National Laboratory .

Two New specias of Frog discovered.

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“It was particularly difficult to locate Paedophryne amauensis due to its diminutive size and the males’ high pitched insect-like mating call,” said Austin. “But it’s a great find. New Guinea is a hotspot of biodiversity, and everything new we discover there adds another layer to our overall understanding of how biodiversity is generated and maintained.”

Austin, curator of herpetology at LSU’s Museum of Natural Science and associate professor of biological sciences, is no stranger to discovering new species, having described numerous species previously unknown to science, including frogs, lizards and parasites.

These most recent species descriptions, which will be published in PLoS ONE on Jan. 11, highlight an interesting trend among the discovery of extremely small vertebrates. The research was supported by the National Science Foundation.

“The size limit of vertebrates, or creatures with backbones, is of considerable interest to biologists because little is understood about the functional constraints that come with extreme body size, whether large or small,” said Austin.

With more than 60,000 vertebrates currently known to man, the largest being the blue whale with an average size of more than 25 meters (75 feet) and the smallest previously being a small Indonesian fish averaging around 8 millimeters, there was originally some thought that extreme size in vertebrates might be associated with aquatic species, as perhaps the buoyancy offers support and facilitates the development of extremism. However, both new species of frogs Austin described are terrestrial, suggesting that living in water is not necessary for small body size.

“The ecosystems these extremely small frogs occupy are very similar, primarily inhabiting leaf litter on the floor of tropical rainforest environments,” said Austin. “We now believe that these creatures aren’t just biological oddities, but instead represent a previously undocumented ecological guild – they occupy a habitat niche that no other vertebrate does.”

Source:PLOS one

 

 

Calculating what’s in the universe from the biggest color 3-D map.

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The Sloan Digital Sky Survey III surveyed 14,000 square degrees of the sky, more than a third of its total area, and delivered over a trillion pixels of imaging data. This image shows over a million luminous galaxies at redshifts indicating times when the universe was between seven and eleven billion years old, from which the sample in the current studies was selected. Credit: David Kirkby of the University of California at Irvine and the SDSS collaboration

Since 2000, the three Sloan Digital Sky Surveys (SDSS I, II, III) have surveyed well over a quarter of the night sky and produced the biggest color map of the universe in three dimensions ever. Now scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and their SDSS colleagues, working with DOE’s National Energy Research Scientific Computing Center (NERSC) based at Berkeley Lab, have used this visual information for the most accurate calculation yet of how matter clumps together – from a time when the universe was only half its present age until now.

“The way galaxies cluster together over vast expanses of the sky tells us how both ordinary visible matter and underlying invisible dark matter are distributed, across space and back in time,” says Shirley Ho, an astrophysicist at Berkeley Lab and Carnegie Mellon University, who led the work. “The distribution gives us cosmic rulers to measure how the universe has expanded, and a basis for calculating what’s in it: how much dark matter, how much dark energy, even the mass of the hard-to-see neutrinos it contains. What’s left over is the ordinary matter and energy we’re familiar with.”

For the present study Ho and her colleagues first selected 900,000 luminous galaxies from among over 1.5 million such galaxies gathered by the Baryon Oscillation Spectrographic Survey, or BOSS, the largest component of the still-ongoing SDSS III. Most of these are ancient red galaxies, which contain only red stars because all their faster-burning stars are long gone, and which are exceptionally bright and visible at great distances. The galaxies chosen for this study populate the largest volume of space ever used for galaxy clustering measurements. Their brightness was measured in five different colors, allowing the redshift of each to be estimated.

“By covering such a large area of sky and working at such large distances, these measurements are able to probe the clustering of galaxies on incredibly vast scales, giving us unprecedented constraints on the expansion history, contents, and evolution of the universe,” says Martin White of Berkeley Lab’s Physics Division, a professor of physics and astronomy at the University of California at Berkeley and chair of the BOSS science survey teams. “The clustering we’re now measuring on the largest scales also contains vital information about the origin of the structure we see in our maps, all the way back to the epoch of inflation, and it helps us to constrain – or rule out – models of the very early universe.”

After augmenting their study with information from other data sets, the team derived a number of such cosmological constraints, measurements of the universe’s contents based on different cosmological models. Among the results: in the most widely accepted model, the researchers found – to less than two percent uncertainty – that dark energy accounts for 73 percent of the density of the universe.

“The way mass clusters on the largest scales is graphed in an angular power spectrum, which shows how matter statistically varies in density across the sky,” says Ho. “The power spectrum gives a wealth of information, much of which is yet to be exploited.” For example, information about inflation – how the universe rapidly expanded shortly after the big bang – can be derived from the power spectrum.

Closely related to the power spectrum are two “standard rulers,” which can be used to measure the history of the expansion of the universe. One ruler has only a single mark – the time when matter and radiation were exactly equal in density.

“In the very early universe, shortly after the big bang, the universe was hot and dominated by photons, the fundamental particles of radiation,” Ho explains. “But as it expanded, it began the transition to a universe dominated by matter. By about 50,000 years after the big bang, the density of matter and radiation were equal. Only when matter dominated could structure form.”

The other cosmic ruler is also big, but it has many more than one mark in the power spectrum; this ruler is called BAO, for baryon acoustic oscillations. (Here, baryon is shorthand for ordinary matter.) Baryon acoustic oscillations are relics of the sound waves that traveled through the early universe when it was a hot, liquid-like soup of matter and photons. After about 50,000 years the matter began to dominate, and by about 300,000 years after the big bang the soup was finally cool enough for matter and light to go their separate ways.

Differences in density that the sound waves had created in the hot soup, however, left their signatures as statistical variations in the distribution of light, detectable as temperature variations in the cosmic microwave background (CMB), and in the distribution of baryons. The CMB is a kind of snapshot that can still be read today, almost 14 billion years later. Baryon oscillations – variations in galactic density peaking every 450 million light-years or so – descend directly from these fluctuations in the density of the early universe.

BAO is the target of the Baryon Oscillation Spectroscopic Survey. By the time it’s completed, BOSS will have measured the individual spectra of 1.5 million galaxies, a highly precise way of measuring their redshifts. The first BOSS spectroscopic results are expected to be announced early in 2012.

Meanwhile the photometric study by Ho and her colleagues deliberately uses many of the same luminous galaxies but derives redshifts from their brightnesses in different colors, extending the BAO ruler back over a previously inaccessible redshift range, from z = 0.45 to z = 0.65 (z stands for redshift).

“As an oscillatory feature in the power spectrum, not many things can corrupt or confuse BAO, which is why it is considered one of the most trustworthy ways to measure dark energy,” says Hee-Jong Seo of the Berkeley Center for Cosmological Physics at Berkeley Lab and the UC Berkeley Department of Physics, who led BAO measurement for the project. “We call BAO a standard ruler for a good reason. As dark energy stretches the universe against the gravity of dark matter, more dark energy places galaxies at a larger distance from us, and the BAO imprinted in their distribution looks smaller. As a standard ruler the true size of BAO is fixed, however. Thus the apparent size of BAO gives us an estimate of the cosmological distance to our target galaxies – which in turn depends on the properties of dark energy.”

Says Ho, “Our study has produced the most precise photometric measurement of BAO. Using data from the newly accessible redshift range, we have traced these wiggles back to when the universe was about half its present age, all the way back to z = 0.54.”

Seo adds, “And that’s to an accuracy within 4.5 percent.”

“With such a large volume of the universe forming the basis of our study, precision cosmology was only possible if we could control for large-scale systematics,” says Ho. Systematic errors are those with a physical basis, including differences in the brightness of the sky, or stars that mimic the colors of distant galaxies, or variations in weather affecting “seeing” at the SDSS’s Sloan Telescope – a dedicated 2.5 meter telescope at the Apache Point Observatory in southern New Mexico.

After applying individual corrections to these and other systematics, the team cross-correlated the effects on the data and developed a novel procedure for deriving the best angular power-spectrum of the universe with the lowest statistical and systematic errors.

With the help of 40,000 central-processing-unit (CPU) hours at NERSC and another 20,000 CPU hours on the Riemann computer cluster at Berkeley Lab, NERSC’s powerful computers and algorithms enabled the team to use all the information from galactic clustering in a huge volume of sky, including the full shape of the power spectrum and, independently, BAO, to get excellent cosmological constraints. The data as well as the analysis output are stored at NERSC.

“Our dataset is purely imaging data, but our results are competitive with the latest large-scale spectroscopic surveys,” Ho says. “What we lack in redshift precision, we make up in sheer volume. This is good news for future imaging surveys like the Dark Energy Survey and the Large Synoptic Survey Telescope, suggesting they can achieve significant cosmological constraints even compared to future spectroscopy surveys.”

“Acoustic scale from the angular power spectra of SDSS-III DR8 photometric luminous galaxies,” by Hee-Jong Seo, Shirley Ho, Martin White, Antonio Cuesta, Ashley Ross, Shun Saito, Beth Reid, Nikhil Padmanabhan, Will J. Percival, Roland de Putter, David Schlegel, Daniel Eisenstein, Xiaoying Xu, Donald Schneider, Ramin Skibba, Licia Verde, Robert Nichol, Dmitry Bizyaev, Howard Brewington, J. Brinkmann, Luiz Costa, J. Gott III, Elena Malanushenko, Viktor Malanushenko, Dan Oravetz, Nathalie Palanque-Delabrouille, Kaike Pan, Francisco Prada, Nicholas Ross, Audrey Simmons, Fernando Simoni, Alaina Shelden, Stephanie Snedden, and Idit Zehavi, has been submitted to Astrophysical Journal and will be available online shortly.

Source: Lawrence Berkeley National Laboratory

Astronomers determine color of the Milky Way Galaxy.

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A team of astronomers in Pitt’s Kenneth P. Dietrich School of Arts and Sciences announced today the most accurate determination yet of the color of the (aptly named) Milky Way Galaxy: “a very pure white, almost mirroring a fresh spring snowfall.” Jeffrey Newman, Pitt professor of physics and astronomy, and Timothy Licquia, a PhD student in physics at Pitt, reported their findings during a presentation at the 219th American Astronomical Society (AAS) Meeting in Austin, Texas.

While color is one of the most important properties of galaxies that astronomers study, it has been difficult to make the measurement for the Milky Way, as our solar system is located well within the Galaxy. Because of this, clouds of gas and dust obscure all but the closest regions of the Galaxy from view, preventing researchers from getting the “big picture” (see http://home.arcor.de/AXEL.MELLINGER/ for a full-color view of the Milky Way, where the obscuration is visible).

“The problem is similar to determining the overall color of the Earth, when you’re only able to tell what Pennsylvania looks like,” Newman noted.

To circumvent this problem, Newman and Licquia set out to determine the Milky Way’s color by using images from other, more distant galaxies that can be viewed more clearly. These galaxies were observed by the Sloan Digital Sky Survey (SDSS), a project in which Pitt had an instrumental role that measured the detailed properties of nearly a million galaxies and has obtained color images of roughly a quarter of the sky. Without the large set of galaxies studied by SDSS to compare to, an accurate color determination was not possible. The new color measurement is allowing Pitt researchers to better understand the development of the Milky Way Galaxy and how it is related to other objects astronomers observe.

“The problem we faced was similar to determining the outside climate when you are in a room with no windows.” said Newman. “You can’t see what’s happening, but you can look online and find current weather conditions someplace where they should be about the same—the local airport, for example.”

The Pitt team identified galaxies similar to the Milky Way in properties that were able to be determined—specifically, their total amount of stars and the rate at which they are creating new stars, which are both related to the brightness and color of a galaxy. The Milky Way Galaxy, the Pitt researchers realized, should then fall somewhere within the range of colors of these matching objects.

“Thanks to SDSS, the large, uniform sample needed to select Milky Way analogs already existed. We just needed to think of the idea for the project, and it was possible,” said Newman. “Although it is a relatively small telescope, only 2.5 meters (100 inches) in diameter, SDSS has been one of the most scientifically productive in history, enabling thousands of new projects like this one.”

Newman described the overall spectrum of light from the Milky Way as being very close to the light seen when looking at spring snow in the early morning, shortly after dawn. Michael Ramsey, Pitt associate professor of geology, notes that new spring snow is the whitest (natural) thing on Earth. Many cultures around the world have given the Milky Way names associated with milk—human vision is not sensitive to colors seen in faint light, so the diffuse glow of the Galaxy at night appears white. That association has proven to be very appropriate, given the Milky Way’s true color.

Astronomers divide most galaxies into two broad categories based on their colors– relatively red galaxies that rarely form new stars and blue galaxies where stars are still being born. (The brightest stars are generally blue, but they are very short-lived on cosmic scales and die out quickly.) The new measurements place the Milky Way near the division between the two classes.

This adds to the evidence that although the Milky Way is still producing stars, it is “on it’s way out,” according to Newman. “A few billion years from now, our Galaxy will be a much more boring place, full of middle-aged stars slowly using up their fuel and dying off, but without any new ones to take their place. It will be less interesting for astronomers in other galaxies to look at, too: The Milky Way’s spiral arms will fade into obscurity when there are no more blue stars left.”

The Milky Way’s color is exceedingly close to the “cosmic color” measured by Ivan Baldry, a professor of astrophysics at Liverpool John Moores University in England, and his collaborators in 2002; these researchers measured the average color of galaxies in the local universe.

“This close match shows that in many ways the Milky Way is a pretty typical galaxy,” said Newman. “This also agrees well with the ‘Copernican Principle’ embraced by the field of cosmology—that, just as the Earth is not in a special place in the solar system, we should not expect to live in an unusual place in the Universe.”

The light from the Milky Way closely matches the light from a D48.4 standard illuminant, or a light bulb with a color temperature of 4700-5000K. “It is well within the range our eye can perceive as white—roughly halfway between the light from old-style incandescent light bulbs and the standard spectrum of white on a television,” said Newman.

Source: University of Pittsburgh