space: 2015

Monday, January 19, 2015

Asteroid to fly by Earth safely on January 26

This graphic depicts the passage of asteroid 2004 BL86, which will come no closer than about three times the distance from Earth to the moon on Jan. 26, 2015. Due to its orbit around the sun, the asteroid is currently only visible by astronomers with large telescopes who are located in the southern hemisphere. But by Jan. 26, the space rock's changing position will make it visible to those in the northern hemisphere

An asteroid, designated 2004 BL86, will safely pass about three times the distance of Earth to the moon on January 26. From its reflected brightness, astronomers estimate that the asteroid is about a third of a mile (0.5 kilometers) in size. The flyby of 2004 BL86 will be the closest by any known space rock this large until asteroid 1999 AN10 flies past Earth in 2027.

At the time of its closest approach on January 26, the asteroid will be approximately 745,000 miles (1.2 million kilometers) from Earth.
"Monday, January 26 will be the closest asteroid 2004 BL86 will get to Earth for at least the next 200 years," said Don Yeomans, who is retiring as manager of NASA's Near Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, California, after 16 years in the position. "And while it poses no threat to Earth for the foreseeable future, it's a relatively close approach by a relatively large asteroid, so it provides us a unique opportunity to observe and learn more."
One way NASA scientists plan to learn more about 2004 BL86 is to observe it with microwaves (http://www.jpl.nasa.gov/news/news.php?release=2006-00a ). NASA's Deep Space Network antenna at Goldstone, California, and the Arecibo Observatory in Puerto Rico will attempt to acquire science data and radar-generated images of the asteroid during the days surrounding its closest approach to Earth.
"When we get our radar data back the day after the flyby, we will have the first detailed images," said radar astronomer Lance Benner of JPL, the principal investigator for the Goldstone radar observations of the asteroid. "At present, we know almost nothing about the asteroid, so there are bound to be surprises."
Asteroid 2004 BL86 was initially discovered on Jan. 30, 2004 by a telescope of the Lincoln Near-Earth Asteroid Research (LINEAR) survey in White Sands, New Mexico.
The asteroid is expected to be observable to amateur astronomers with small telescopes and strong binoculars.
"I may grab my favorite binoculars and give it a shot myself," said Yeomans. "Asteroids are something special. Not only did asteroids provide Earth with the building blocks of life and much of its water, but in the future, they will become valuable resources for mineral ores and other vital natural resources. They will also become the fueling stops for humanity as we continue to explore our solar system. There is something about asteroids that makes me want to look up."
NASA's Near-Earth Object Program Office is experiencing its first transition in leadership since it was formed almost 17 years ago. On Jan. 9, after a 39-year-long career at JPL, Yeomans retired. Paul Chodas, a long-time member of Yeomans' team at JPL, has been designated as the new manager.
NASA detects, tracks and characterizes asteroids and comets using both ground- and space-based telescopes. Elements of the Near-Earth Object Program, often referred to as "Spaceguard," discover these objects, characterize a subset of them and identify their close approaches to determine if any could be potentially hazardous to our planet.
JPL manages the Near-Earth Object Program Office for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena.
More information about asteroids and near-Earth objects is at:
http://www.jpl.nasa.gov/asteroidwatch.
To get updates on passing space rocks, follow:
http://twitter.com/asteroidwatch

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The above story is based on materials provided by NASA/Jet Propulsion Laboratory. Note: Materials may be edited for content and length.

Monday, January 12, 2015

Study casts doubt on mammoth-killing cosmic impact

Large asteroid hitting Earth (stock illustration)

Rock soil droplets formed by heating most likely came from Stone Age house fires and not from a disastrous cosmic impact 12,900 years ago, according to new research from the University of California, Davis. The study, of soil from Syria, is the latest to discredit the controversial theory that a cosmic impact triggered the Younger Dryas cold period.

The Younger Dryas lasted a thousand years and coincided with the extinction of mammoths and other great beasts and the disappearance of the Paleo-Indian Clovis people. In the 1980s, some researchers put forward the idea that the cool period, which fell between two major glaciations, began when a comet or meteorite struck North America.
In the new study, published online in the Journal of Archaeological Science, scientists analyzed siliceous scoria droplets -- porous granules associated with melting -- from four sites in northern Syria dating back 10,000 to 13,000 years ago. They compared them to similar scoria droplets previously suggested to be the result of a cosmic impact at the onset of the Younger Dryas.
"For the Syria side, the impact theory is out," said lead author Peter Thy, a project scientist in the UC Davis Department of Earth and Planetary Sciences. "There's no way that can be done."
The findings supporting that conclusion include:

The composition of the scoria droplets was related to the local soil, not to soil from other continents, as one would expect from an intercontinental impact.
The texture of the droplets, thermodynamic modeling and other analyses showed the droplets were formed by short-lived heating events of modest temperatures, and not by the intense, high temperatures expected from a large impact event.
And in a key finding, the samples collected from archaeological sites spanned 3,000 years. "If there was one cosmic impact," Thy said, "they should be connected by one date and not a period of 3,000 years."

So if not resulting from a cosmic impact, where did the scoria droplets come from? House fires. The study area of Syria was associated with early agricultural settlements along the Euphrates River. Most of the locations include mud-brick structures, some of which show signs of intense fire and melting. The study concludes that the scoria formed when fires ripped through buildings made of a mix of local soil and straw.

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The above story is based on materials provided by University of California - Davis. Note: Materials may be edited for content and length.

Journal Reference:

P. Thy, G. Willcox, G.H. Barfod, D.Q. Fuller. Anthropogenic origin of siliceous scoria droplets from Pleistocene and Holocene archaeological sites in northern Syria. Journal of Archaeological Science, 2015; 54: 193 DOI: 10.1016/j.jas.2014.11.027

Saturday, January 10, 2015

“Machine Learning” Helps Astronomers Identify Basic Properties of Stars

A Machine Learning Method to Learn About the Stars

A newly published study details how astronomers have turned to a method called “machine learning” to help them understand the properties of large numbers of stars

Astronomers are enlisting the help of machines to sort through thousands of stars in our galaxy and learn their sizes, compositions and other basic traits.
The research is part of the growing field of machine learning, in which computers learn from large data sets, finding patterns that humans might not otherwise see. Machine learning is in everything from media-streaming services that predict what you want to watch, to the post office, where computers automatically read handwritten addresses and direct mail to the correct zip codes.
Now astronomers are turning to machines to help them identify basic properties of stars based on sky survey images. Normally, these kinds of details require a spectrum, which is a detailed sifting of the starlight into different wavelengths. But with machine learning, computer algorithms can quickly flip through available stacks of images, identifying patterns that reveal a star’s properties. The technique has the potential to gather information on billions of stars in a relatively short time and with less expense.
“It’s like video-streaming services not only predicting what you would like to watch in the future, but also your current age, based on your viewing preferences,” said Adam Miller of NASA’s Jet Propulsion Laboratory in Pasadena, California, lead author of a new report on the findings appearing in the Astrophysical Journal. “We are predicting fundamental properties of the stars.”
Miller presented the results today at the annual American Astronomical Society meeting in Seattle.
Machine learning has been applied to the cosmos before; what makes this latest effort unique is that it is the first to predict specific traits of stars, such as size and metal content, using images of those stars taken over time. These traits are essential to learning about when a star was born, and how it has changed since that time.
“With more information about the different kinds of stars in our Milky Way galaxy, we can better map the galaxy’s structure and history,” said Miller.
Every night, telescopes around the world obtain thousands of images of the sky. The flood of new data is only expected to rise with upcoming wide-field surveys like the Large Synoptic Survey Telescope (LSST), a National Science Foundation and Department of Energy project that will be based in Chile. That survey will image the entire visible sky every few nights, gathering data on billions of stars and how some of those stars change in brightness over time. NASA’s Kepler mission has already captured the same kind of time-varying data on hundreds of thousands of stars.
Humans alone can’t easily make sense of all this data. That is where machines, or in this case, computers using specialized algorithms, can help out.
But before the machines can learn, they first need a “training period.” Miller and his colleagues started with 9,000 stars as their training set. They obtained spectra for these stars, which revealed several of their basic properties: sizes, temperatures and the amount of heavy elements, such as iron. The varying brightness of the stars had also been recorded by the Sloan Digital Sky Survey, producing plots called light curves. By feeding the computer both sets of data, it could then make associations between the star properties and the light curves.
Once the training phase was over, the computer was able to make predictions on its own about other stars by only analyzing light-curves.
“We can discover and classify new types of stars without the need for spectra, which are expensive and time-consuming to obtain,” said Miller.
The technique essentially works in the same way as email spam filters. The spam filters are programmed to identify key words associated with junk mail, and then remove the unwanted emails containing those words. With time, a user continues to “teach” the filtering program more key words, and the program becomes better at filtering spam. The machine learning program used by Miller and collaborators likewise becomes better at accurately predicting properties of the stars with additional training from the astronomers.
The team’s next goal is to get their computers smart enough to handle the more than 50 million variable stars that the LSST project will observe.
“This is an exciting time to be applying advanced algorithms to astronomy,” said Miller. “Machine learning allows us to mine for rare and obscure gems within the deep data sets that astronomers are only now beginning to acquire.”
Publication: A. A. Miller, et al., “A Machine-learning Method to Infer Fundamental Stellar Parameters from Photometric Light Curves,” 2015, ApJ, 798, 122; doi:10.1088/0004-637X/798/2/122
PDF Copy of the Study: A Machine Learning Method to Infer Fundamental Stellar Parameters from Photometric Light Curves
Source: Whitney Clavin, Jet Propulsion Laboratory

Wednesday, January 7, 2015

Planet-hunting satellite observes supermassive black hole

Joner in the observatory at BYU's Eyring Science Center

Fire consumes wood ferociously, in a deadly blaze -- but the substances used to treat wood to resist burning can also be noxious and toxic. A Stony Brook University Materials Science Professor guided an undergraduate and two Long Island high school students as they developed a patent-pending, environmentally sustainable way to render the wood used in construction flame retardant -- and 5x stronger -- using natural materials.

"Our Office of Technology Transfer and Industry Relations has already gotten interest from several companies regarding possible license," says Miriam Rafailovich, who oversaw the research. Rafailovich is Distinguished Professor in the Department of Materials Science and Co-Director of the Program in Chemical and Molecular Engineering at Stony Brook University.
The work took place at the Garcia Center for Polymers at Engineered Interfaces at Stony Brook as part of the Garcia Research Scholar Program. The pre-college program offers the opportunity for high school students and teachers to perform research at the forefront of polymer science and technology alongside Garcia Center faculty and staff.
"The students were the primary drivers in this work; I guided them in addressing the pertinent questions," Rafailovich says. The research was initiated by Tehila Stone, a former student in the Garcia program. Stone worked as an undergraduate mentor at Stony Brook this past summer with the high school students, Daniel Kim and Noah Davis.
Davis, a senior at Earl L. Vandermuelen High School on Long Island, says he has always been interested in math and the sciences. "This led me to look for research programs over the summer. I learned about the Garcia Program, and the focus on polymer-based engineering immediately drew my interest." Kim, a senior at Smithtown High School West -- also on Long Island -- says "the Garcia Program was the optimal choice for access to a quality lab and great mentorship."
The team started off with a simple 2x4 from Lowe's; the flame retardant is a phosphor-based material safe for the environment. The researchers engineered a compound that impregnates wood's natural structure, forming a wood-plastic composite that exceeds UL 94 V-O criteria for safety of flammability. "The breakthrough was in the formulation of a compound that extinguishes a flame without decomposing into toxic byproducts," Rafailovich says.
That's ideal for the construction industry. Says Kim, "What interested me the most was that it could be used to safeguard homes and buildings. The idea that the world can really benefit from flame retardant wood was my greatest motivation for this project."
The interdisciplinary effort involved Dr. Marcia Simon, Professor and Director for Graduate Studies in the Department of Oral Biology and Pathology at the Stony Brook University School of Dental Medicine. Simon is also Director of the Living Skin Bank, and helped design the toxicology testing and evaluate EPA reports.
"The students chose to use resorcinol bis(diphenyl phosphate) (RDP), which the EPA has declared a preferred substitute for halogenated flame retardants," Simon says. "Preliminary data in our laboratory confirms that when RDP is reacted with cellulose, or clays, such as was done by the students, it is safe and non-cytoxic. Although the finished product is safe, in vitro tests suggest that the unreacted RDP liquid, used in industrial plants, can be cytotoxic and should be handled with care."
Rafailovich is pleased the young learners had this opportunity. "I believe that a great deal of innovation is possible if we encourage students to explore their ideas," she says. "Students are more in-tune than older adults with the latest science developments in the consumer arena, but don't have the tools and knowledge to act on these ideas. We hope that by helping them do that, they will learn the power of science and be inspired to remain in the field."
Davis certainly feels that way. "Dan and I worked with different chemicals and beakers to measure out volumes; we used heating ovens to create reactions between the wood and chemicals; after the wood samples were created, we tested their properties with the UL-94 flame test and an Izod impact test. While I already had a large interest in science before the program, the experience only furthered that interest. I currently want to study biomedical engineering, and see this as a direct result of my experiences within the program."
Says Rafailovich, "Stony Brook is a unique place where all this is possible. New science is problem-focused, and requires interdisciplinary collaborations across all areas of the campus. With its medical, dental, and engineering facilities, and proximity to Brookhaven National Laboratory and outstanding industrial parks, Stony Brook is ideal for this type of research."
It's also a good place for translating research into applications. "Our Office of Technology Transfer and Industry Relations is exceptional," Rafailovich says. "It requires a special staff to keep up with the diversity of science and industry, and over the years Stony Brook has established this network. A technology transfer staff that teaches and involves student is even more rare, making the Stony Brook years very memorable for any student who is fortunate to experience this."

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8 Newfound Alien Worlds Could Potentially Support Life

Astronomers have discovered eight new exoplanets that may be capable of supporting life as we know it, including what they say are the two most Earthlike alien worlds yet found.
All eight newfound alien planets appear to orbit in their parent stars' habitable zone — that just-right range of distances that may allow liquid water to exist on a world's surface — and all of them are relatively small, researchers said.
"Most of these planets have a good chance of being rocky, like Earth," study lead author Guillermo Torres, of the Harvard-Smithsonian Center for Astrophysics (CfA), said in a statement

The haul doubles the number of known habitable-zone planets that are potentially rocky, study team members said.
The newly discovered worlds were all detected by NASA's prolific Kepler space telescope, then confirmed using observations by other telescopes and a computer program that assessed the statistical probability that they are bona fide planets (as opposed to false positives).
While none of the eight is a true "alien Earth," two of them — known as Kepler-438b and Kepler-442b — stand out for their similarities to our home planet (though both worlds orbit red dwarfs, stars that are smaller and dimmer than Earth's sun)

Kepler-438b, which lies 470 light-years from our solar system, is just 12 percent wider than Earth and has a 70 percent chance of being rocky, study team members said. The planet completes one orbit every 35 days and receives about 40 percent more energy from its star than Earth does from the sun.
Kepler-442b is about one-third larger than Earth, and has a 60 percent chance of being rocky. The exoplanet's orbital period is 112 days, and it gets about two-thirds as much energy as Earth, scientists said. Kepler-442b is about 1,100 light-years from Earth.
As intriguing as these two worlds are, there's no guarantee that either of them could actually host life, team members stressed.
"We don't know for sure whether any of the planets in our sample are truly habitable," co-author David Kipping, also of the CfA, said in the same statement. "All we can say is that they're promising candidates." [The Search For Another Earth (Video)]
Such hedging is unavoidable at this point, because researchers just don't have enough information. For starters, there's the uncertainty about the planets' composition, as evidenced by the estimated rockiness probabilities. (Nobody knows for sure where the dividing line lies between rocky and gaseous worlds, in terms of planet size.)
Furthermore, a planet's surface temperature is highly dependent on the composition and thickness of its atmosphere, and nothing is known about the air surrounding Kepler-438b, Kepler-442b or any of the other newfound worlds.
And some scientists employ a more restrictive definition of "habitable zone" than others. Indeed, study team member Douglas Caldwell, who presented the results today (Jan. 6) at the annual winter meeting of the American Astronomical Society (AAS) in Seattle, said that only three of the newly confirmed planets are "securely" in the habitable zone.
But he's not discounting the life-hosting chances of the other five.
"All of these planets are small, all of them are potentially habitable — and, in fact, have a more than a 50 percent chance of being in the slightly extended habitable zone — and all are interesting," Caldwell, who's based at the SETI (Search for Extraterrestrial Intelligence) Institute in Mountain View, California, said during a AAS press briefing today.

Tuesday, January 6, 2015

Milky Way core drives wind at 2 million miles per hour

This graphic shows how NASA's Hubble Space Telescope probed the light from a distant quasar to analyze the so-called Fermi Bubbles, two lobes of material being blown out of the core of our Milky Way galaxy. The quasar's light passed through one of the bubbles. Imprinted on that light is information about the outflow's speed, composition, and eventually mass. The outflow was produced by a violent event that happened about 2 million years ago in our galaxy's core

At a time when our earliest human ancestors had recently mastered walking upright, the heart of our Milky Way galaxy underwent a titanic eruption, driving gases and other material outward at 2 million miles per hour.

Now, at least 2 million years later, astronomers are witnessing the aftermath of the explosion: billowing clouds of gas towering about 30,000 light-years above and below the plane of our galaxy.
The enormous structure was discovered five years ago as a gamma-ray glow on the sky in the direction of the galactic center. The balloon-like features have since been observed in X-rays and radio waves. But astronomers needed NASA's Hubble Space Telescope to measure for the first time the velocity and composition of the mystery lobes. They now seek to calculate the mass of the material being blown out of our galaxy, which could lead them to determine the outburst's cause from several competing scenarios.
Astronomers have proposed two possible origins for the bipolar lobes: a firestorm of star birth at the Milky Way's center or the eruption of its supermassive black hole. Although astronomers have seen gaseous winds, composed of streams of charged particles, emanating from the cores of other galaxies, they are getting a unique, close-up view of our galaxy's own fireworks.
"When you look at the centers of other galaxies, the outflows appear much smaller because the galaxies are farther away," said Andrew Fox of the Space Telescope Science Institute in Baltimore, Maryland, lead researcher of the study. "But the outflowing clouds we're seeing are only 25,000 light-years away in our galaxy. We have a front-row seat. We can study the details of these structures. We can look at how big the bubbles are and can measure how much of the sky they are covering."
Fox's results will be published in The Astrophysical Journal Letters and will be presented at the American Astronomical Society meeting in Seattle, Washington.
The giant lobes, dubbed Fermi Bubbles, initially were spotted using NASA's Fermi Gamma-ray Space Telescope. The detection of high-energy gamma rays suggested that a violent event in the galaxy's core aggressively launched energized gas into space. To provide more information about the outflows, Fox used Hubble's Cosmic Origins Spectrograph (COS) to probe the ultraviolet light from a distant quasar that lies behind the base of the northern bubble. Imprinted on that light as it travels through the lobe is information about the velocity, composition, and temperature of the expanding gas inside the bubble, which only COS can provide.
Fox's team was able to measure that the gas on the near side of the bubble is moving toward Earth and the gas on the far side is travelling away. COS spectra show that the gas is rushing from the galactic center at roughly 2 million miles an hour (3 million kilometers an hour).
"This is exactly the signature we knew we would get if this was a bipolar outflow," explained Rongmon Bordoloi of the Space Telescope Science Institute, a co-author on the science paper. "This is the closest sightline we have to the galaxy's center where we can see the bubble being blown outward and energized."
The COS observations also measure, for the first time, the composition of the material being swept up in the gaseous cloud. COS detected silicon, carbon, and aluminum, indicating that the gas is enriched in the heavy elements produced inside stars and represents the fossil remnants of star formation.
COS measured the temperature of the gas at approximately 17,500 degrees Fahrenheit, which is much cooler than most of the super-hot gas in the outflow, thought to be at about 18 million degrees Fahrenheit. "We are seeing cooler gas, perhaps interstellar gas in our galaxy's disk, being swept up into that hot outflow," Fox explained.
This is the first result in a survey of 20 faraway quasars whose light passes through gas inside or just outside the Fermi Bubbles -- like a needle piercing a balloon. An analysis of the full sample will yield the amount of mass being ejected. The astronomers can then compare the outflow mass with the velocities at various locations in the bubbles to determine the amount of energy needed to drive the outburst and possibly the origin of the explosive event.
One possible cause for the outflows is a star-making frenzy near the galactic center that produces supernovas, which blow out gas. Another scenario is a star or a group of stars falling onto the Milky Way's supermassive black hole. When that happens, gas superheated by the black hole blasts deep into space. Because the bubbles are short-lived compared to the age of our galaxy, it suggests this may be a repeating phenomenon in the Milky Way's history. Whatever the trigger is, it likely occurs episodically, perhaps only when the black hole gobbles up a concentration of material.
"It looks like the outflows are a hiccup," Fox said. "There may have been repeated ejections of material that have blown up, and we're catching the latest one. By studying the light from the other quasars in our program, we may be able to detect the fossils of previous outflows."
Galactic winds are common in star-forming galaxies, such as M82, which is furiously making stars in its core. "It looks like there's a link between the amount of star formation and whether or not these outflows happen," Fox said. "Although the Milky Way overall currently produces a moderate one to two stars a year, there is a high concentration of star formation close to the core of the galaxy."

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The above story is based on materials provided by Space Telescope Science Institute (STScI). Note: Materials may be edited for content and length.

Journal Reference:

Andrew J. Fox, Rongmon Bordoloi, Blair D. Savage, Felix J. Lockman, Edward B. Jenkins, Bart P. Wakker, Joss Bland-Hawthorn, Svea Hernandez, Tae-Sun Kim, Robert A. Benjamin, David V. Bowen, Jason Tumlinson. Probing the Fermi Bubbles in Ultraviolet Absorption: A Spectroscopic Signature of the Milky Way's Biconical Nuclear Outflow. The Astrophysical Journal Letters, 2015 [link]

Record-breaking black hole outburst detected

An image of a simulation of the gas cloud's encounter with Sgr A*. The blue lines mark the orbits of the so-called "S" stars that are in close orbits around the supermassive black hole

Last September, after years of watching, a team of scientists led by Amherst College astronomy professor Daryl Haggard observed and recorded the largest-ever flare in X-rays from a supermassive black hole at the center of the Milky Way. The astronomical event, which was detected by NASA's Chandra X-ray Observatory, puts the scientific community one step closer to understanding the nature and behavior of supermassive black holes.

Haggard and her colleagues discussed the flare today during this year's meeting of the American Astronomical Society in Seattle.
Supermassive black holes are the largest of black holes, and all large galaxies have one. The one at the center of our galaxy, the Milky Way, is called Sagittarius A* (or, Sgr A*, as it is called), and scientists estimate that it contains about four and a half million times the mass of our Sun.
Scientists working with Chandra have observed Sgr A* repeatedly since the telescope was launched into space in 1999. Haggard and fellow astronomers were originally using Chandra to see if Sgr A* would consume parts of a cloud of gas, known as G2.
"Unfortunately, the G2 gas cloud didn't produce the fireworks we were hoping for when it got close to Sgr A*," she said. "However, nature often surprises us and we saw something else that was really exciting."
Haggard and her team detected an X-ray outburst last September that was 400 times brighter than the usual X-ray output from Sgr A*. This "megaflare" was nearly three times brighter than the previous record holder that was seen in early 2012. A second enormous X-ray flare, 200 times brighter than Sgr A* in its quiet state, was observed with Chandra on October 20, 2014.
Haggard and her team have two main ideas about what could be causing Sgr A* to erupt in this extreme way. One hypothesis is that the gravity of the supermassive black hole has torn apart a couple of asteroids that wandered too close. The debris from such a "tidal disruption" would become very hot and produce X-rays before disappearing forever across the black hole's point of no return (called the "event horizon").
"If an asteroid was torn apart, it would go around the black hole for a couple of hours -- like water circling an open drain -- before falling in," said colleague and co-principal investigator Fred Baganoff of the Massachusetts Institute of Technology in Cambridge, MA. "That's just how long we saw the brightest X-ray flare last, so that is an intriguing clue for us to consider."
If that theory holds up, it means astronomers have found evidence for the largest asteroid ever to be torn apart by the Milky Way's black hole.
Another, different idea is that the magnetic field lines within the material flowing towards Sgr A* are packed incredibly tightly. If this were the case, these field lines would occasionally interconnect and reconfigure themselves. When this happens, their magnetic energy is converted into the energy of motion, heat and the acceleration of particles -- which could produce a bright X-ray flare. Such magnetic flares are seen on the Sun, and the Sgr A* flares have a similar pattern of brightness levels to the solar events.
"At the moment, we can't distinguish between these two very different ideas," said Haggard. "It's exciting to identify tensions between models and to have a chance to resolve them with present and future observations."
In addition to the giant flares, Haggard and her team also collected more data on a magnetar -- a neutron star with a strong magnetic field -- located close to Sgr A*. This magnetar is undergoing a long X-ray outburst, and the Chandra data are allowing astronomers to better understand this unusual object.
As for the G2: Astronomers estimate that the gas cloud made its closest approach -- still about 15 billion miles away from the edge of the black hole -- in the spring of 2014. The researchers estimate the record breaking X-ray flares were produced about a hundred times closer to the black hole, making it very unlikely that the Chandra flares were associated with G2.

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Hubble's high-definition panoramic view of Andromeda galaxy

The largest NASA Hubble Space Telescope image ever assembled, this sweeping bird's-eye view of a portion of the Andromeda galaxy (M31) is the sharpest large composite image ever taken of our galactic next-door neighbor. Though the galaxy is over 2 million light-years away, the Hubble telescope is powerful enough to resolve individual stars in a 61,000-light-year-long stretch of the galaxy's pancake-shaped disk. It's like photographing a beach and resolving individual grains of sand. And, there are lots of stars in this sweeping view -- over 100 million, with some of them in thousands of star clusters seen embedded in the disk. The panorama is the product of the Panchromatic Hubble Andromeda Treasury (PHAT) program. Images were obtained from viewing the galaxy in near-ultraviolet, visible, and near-infrared wavelengths, using the Advanced Camera for Surveys and the Wide Field Camera 3 aboard Hubble. This cropped view shows a 48,000-light-year-long stretch of the galaxy in its natural visible-light color, as photographed with Hubble's Advanced Camera for Surveys in red and blue filters July 2010 through October 2013.

This ambitious photographic cartography of the Andromeda galaxy represents a new benchmark for precision studies of large spiral galaxies that dominate the universe's population of over 100 billion galaxies. Never before have astronomers been able to see individual stars inside an external spiral galaxy over such a large contiguous area. Most of the stars in the universe live inside such majestic star cities, and this is the first data that reveal populations of stars in context to their home galaxy.
Hubble traces densely packed stars extending from the innermost hub of the galaxy, seen at left. Moving out from this central galactic bulge, the panorama sweeps from the galaxy's central bulge across lanes of stars and dust to the sparser outer disk. Large groups of young blue stars indicate the locations of star clusters and star-forming regions. The stars bunch up in the blue ring-like feature toward the right side of the image. The dark silhouettes trace out complex dust structures. Underlying the entire galaxy is a smooth distribution of cooler red stars that trace Andromeda's evolution over billions of years.
Because the galaxy is only 2.5 million light-years from Earth, it is a much bigger target in the sky than the myriad galaxies Hubble routinely photographs that are billions of light-years away. This means that the Hubble survey is assembled together into a mosaic image using 7,398 exposures taken over 411 individual pointings.
The panorama is the product of the Panchromatic Hubble Andromeda Treasury (PHAT) program. Images were obtained from viewing the galaxy in near-ultraviolet, visible, and near-infrared wavelengths, using the Advanced Camera for Surveys and the Wide Field Camera 3 aboard Hubble. This cropped view shows a 48,000-light-year-long stretch of the galaxy in its natural visible-light color, as photographed with Hubble's Advanced Camera for Surveys in red and blue filters July 2010 through October 2013.
The panorama is being presented at the 225th Meeting of the Astronomical Society in Seattle, Washington.

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Monday, January 5, 2015

For 15 days in June, sun to block all communication with Mangalyaan | sci-spacescience.blogspot.com

MUMBAI: There will be a nail-biting fortnight in June for the Isro team because there will be absolutely no communication with the Mars Orbiter Mission (MOM) during that period.
"It [communication break] will be for the first time for such a long period since its launch on November 5, 2013," former Isro chairman K Radhakrishnan said at the Indian Science Congress on Friday.
In a question-and-answer session with former Isro scientist Pramod Kale at the first plenary meeting of the 102nd edition of the congress, Radhakrishnan said that the blackout will be the result of an eclipse.

MOM project director Subbiah Arunan, who is scheduled to address the congress on Monday, said the blackout will be from June 8 to 22 because the Sun will come between Earth and Mars, blocking the view of the Red Planet.
Arunan said that during the blackout data cannot be transmitted to the spacecraft or downlinked. "MOM will be fully in autonomous mode," he said.
Arunan said the scenario had been tested in the mission simulation tests.
"There have been many manoeuvres when there has been a communication blackout, but this is the first time it is happening for as long as 14 day," Arunan said. "We are confident that there will be no problems."
Arunan said in May 2016 there will be what is known as a "whiteout" period when Earth will come between the Sun and Mars, blocking communication with the spacecraft for about a fortnight again.
Radhakrishnan, who retired on Wednesday, told the large gathering of students and scientists that the quality of data downloaded from the five payloads on board MOM was excellent. "After a series of reviews, they will get published," he said.
Moving to other matters, he said the cryogenic stage for the new LVM 3 rocket would be ready in two years and will be three times more powerful than the existing ones.
He said that 300 industrial firms were participating in the space programme and that in the next few years "we want a launcher like the PSLV coming out of an industry".
About the participation of students in the space programme, Radhakrishnan said they were looking for centres of excellence in space technology in the academic world. To a question about the human space flight programme, he said some more developments had to take place before the country could declare itself ready for such a mission.