Astronomy blog

February 3, 2010, 2:23 PM CT

Merging galaxies create a binary quasar

Astronomers have found the first clear evidence of a binary quasar within a pair of actively merging galaxies. Quasars are the extremely bright centers of galaxies surrounding super-massive black holes, and binary quasars are pairs of quasars bound together by gravity. Binary quasars, like other quasars, are believed to be the product of galaxy mergers. Until now, however, binary quasars have not been seen in galaxies that are unambiguously in the act of merging. But images of a new binary quasar from the Carnegie Institution's Magellan telescope in Chile show two distinct galaxies with "tails" produced by tidal forces from their mutual gravitational attraction.

"This is really the first case in which you see two separate galaxies, both with quasars, that are clearly interacting," says Carnegie astronomer John Mulchaey who made observations crucial to understanding the galaxy merger.

Most, if not all, large galaxies, such as our galaxy the Milky Way, host super-massive black holes at their centers. Because galaxies regularly interact and merge, astronomers have assumed that binary super-massive black holes have been common in the Universe, particularly during its early history. Black holes can only be detected as quasars when they are actively accreting matter, a process that releases vast amounts of energy. A leading theory is that galaxy mergers trigger accretion, creating quasars in both galaxies. Because most of such mergers would have happened in the distant past, binary quasars and their associated galaxies are very far away and therefore difficult for most telescopes to resolve......... Posted by: Sean      Read more         Source

January 28, 2010, 0:19 AM CT

Student-built satellite

A tiny communications satellite designed and built by University of Colorado at Boulder undergraduates has been selected as one of three university research satellites to be launched into orbit in November as part of a NASA space education initiative.

The three satellites, dubbed "CubeSats" because of their shape, were built by CU-Boulder, Montana State University and Kentucky Space, which is a consortium of state universities. CubeSats are roughly four inches on a side, have a volume of about one quart and weigh about 2.2 pounds. The satellites are being flown as part of NASA's Educational Launch of Nanosatellite, or ELaNA, mission, said Chris Koehler, director of the Colorado Space Grant Consortium, or COSGC, which is headquartered at CU-Boulder.

The CU-Boulder satellite, named Hermes, was designed, built and tested by roughly 100 COSGC students on the CU-Boulder campus -- nearly all undergraduates -- over a period of about two and one-half years, said Koehler. The goal of the mission is to improve communications systems in tiny satellites through on-orbit testing of a high data-rate communication system that will allow researchers and engineers to downlink large quantities of information.

"This is great news for the students and for the Colorado Space Grant Consortium," said Koehler. "This is a homegrown CU-Boulder satellite and these students have pushed the capabilities of communication systems by integrating them into a very tiny satellite." Based in the CU-Boulder College of Engineering and Applied Science, COSGC is funded by NASA and is a statewide organization involving 16 colleges, universities and institutions around Colorado......... Posted by: Sean      Read more         Source

January 25, 2010, 8:15 AM CT

New Research On Star Formation

"Crazy" and "cool" are two of the words Michigan State University astronomer Megan Donahue uses to describe the two distinct "tails" found on a long tail of gas that is thought to beforming stars where few stars have been formed before.

Donahue was part of an international team of astronomers that viewed the gas tail with a very long, new observation made by the Chandra X-ray Observatory and detailed it in a paper published this month in the publication Astrophysical Journal.

"The double tail is very cool - that is, interesting - and ridiculously hard to explain," said Donahue, a professor in MSU's Department of Physics and Astronomy. "It could be two different sources of gas or something to do with magnetic fields. We just don't know".

What is also unusual is the gas tail, which is more than 200,000 light years in length, extends well outside any galaxy. It is within objects such as this that new stars are formed, but commonly within the confines of a galaxy.

"This system is really crazy because where we're seeing the star formation is well away from any galaxy," Donahue said. "Star formation happens primarily in the disks of galaxies. What we're seeing here is very unexpected".

This gas tail was originally spotted by astronomers three years ago using a multitude of telescopes, including NASA's Chandra X-ray Observatory and the SOuthern Astrophysical Research telescope, a Chilean-based observatory in which MSU is one of the partners. The new observations show a second tail, and a fellow galaxy, ESO 137-002, that also has a tail of hot X-ray-emitting gas......... Posted by: Sean      Read more         Source

January 25, 2010, 0:01 AM CT

Differences between Ganymede and Callisto

Differences in the number and speed of cometary impacts onto Jupiter's large moons Ganymede and Callisto some 3.8 billion years ago can explain their vastly different surfaces and interior states, as per research by researchers at the Southwest Research Institute appearing online in Nature Geoscience Jan. 24, 2010.

Ganymede and Callisto are similar in size and are made of a similar mixture of ice and rock, but data from the Galileo and Voyager spacecraft show that they look different at the surface and on the inside. A conclusive explanation for the differences between Ganymede and Callisto has eluded researchers since the Voyager Jupiter encounters 30 years ago.

Dr. Amy C. Barr and Dr. Robin M. Canup of the SwRI Planetary Science Directorate created a model of melting by cometary impacts and rock core formation to show that Ganymede and Callisto's evolutionary paths diverged about 3.8 billion years ago during the Late Heavy Bombardment, the phase in lunar history dominated by large impact events.

"Impacts during this period melted Ganymede so thoroughly and deeply that the heat could not be quickly removed. All of Ganymede's rock sank to its center the same way that all the chocolate chips sink to the bottom of a melted carton of ice cream," says Barr. "Callisto received fewer impacts at lower velocities and avoided complete melting"......... Posted by: Sean      Read more         Source

Mon, 25 Jan 2010 05:36:26 GMT

Meteorite hits doctor's office

Of course, it happened with a doctor’s office, what else? An excerpt from the Washington Post report:

“The floor just outside examination room No. 2 — about 10 feet from where Ciampi had been doing paperwork — was littered with small pieces of wood, plaster and insulation. Upon inspection, more debris lay inside the room. He saw three chunks of stone on the floor that together formed a rock about the size of a tennis ball, with a glassy-smooth surface. Then he saw a hole about the size of the rock in the tile ceiling, and a tear in the maroon carpet where the rock had landed,” writes Paul Duggan of the Washington Post.

Posted by: Bertalan      Read more     Source

January 13, 2010, 7:45 AM CT

First Comprehensive Sky Map

Ever since NASA's Interstellar Boundary Explorer, or IBEX, mission researchers released the first comprehensive sky map of our solar system's edge in particles, solar physicists have been busy revising their models to account for the discovery of a narrow "ribbon" of bright emission that was completely unexpected and not predicted by any model at the time.

Further study by a team of researchers funded through NASA's Heliophysics Guest Investigator program has produced a revised model that explains and closely reproduces the IBEX result by incorporating a single new effect into an existing model. The new effect, put forward by the IBEX team soon after sighting of the ribbon, is that the magnetic field surrounding our solar systemcalled the local galactic magnetic fieldacts like a mirror for the particles that IBEX sees.

The results appear in the January 10 issue of the Astrophysical Journal Letters Jacob Heerikhuisen, a solar physicist at the University of Alabama in Huntsville, is the main author of the paper. Heerikhuisen and colleagues believe the orientation of the local galactic magnetic field is closely correlation to the location of the ribbon in the sky.

Charged particles "orbit" magnetic field lines. When they suddenly lose their charge, they fly off in a straight line maintaining their current direction. Only particles that orbit the magnetic mirror, where it faces us directly, can flow back toward us and are captured by IBEX......... Posted by: Sean      Read more         Source

January 11, 2010, 8:04 AM CT

Fossil fireballs from supernovae

Studies of two supernova remnants using the Japan-U.S. Suzaku observatory have revealed never-before-seen embers of the high-temperature fireballs that immediately followed the explosions. Even after thousands of years, gas within these stellar wrecks retain the imprint of temperatures 10,000 times hotter than the sun's surface.

"This is the first evidence of a new type of supernova remnant -- one that was heated right after the explosion," said Hiroya Yamaguchi at the Institute of Physical and Chemical Research in Japan.

A supernova remnant commonly cools quickly due to rapid expansion following the explosion. Then, as it sweeps up tenuous interstellar gas over thousands of years, the remnant gradually heats up again.

Capitalizing on the sensitivity of the Suzaku satellite, a team led by Yamaguchi and Midori Ozawa, a graduate student at Kyoto University, detected unusual features in the X-ray spectrum of IC 443, better known to amateur astronomers as the Jellyfish Nebula.

The remnant, which lies some 5,000 light-years away in the constellation Gemini, formed about 4,000 years ago. The X-ray emission forms a roughly circular patch in the northern part of the visible nebulosity.

Suzaku's X-ray Imaging Spectrometers (XISs) separate X-rays by energy in much the same way as a prism separates light into a rainbow of colors. This allows astronomers to tease out the types of processes responsible for the radiation......... Posted by: Sean      Read more         Source

January 6, 2010, 8:15 AM CT

Galactic GPS

Radio astronomers have uncovered 17 millisecond pulsars in our galaxy by studying unknown high-energy sources detected by NASA's Fermi Gamma-ray Space Telescope. The astronomers made the discovery in less than three months. Such a jump in the pace of locating these hard-to-find objects holds the promise of using them as a kind of "galactic GPS" to detect gravitational waves passing near Earth.

A pulsar is the rapidly spinning and highly magnetized core left behind when a massive star explodes. Because only rotation powers their intense gamma-ray, radio and particle emissions, pulsars gradually slow as they age. But the oldest pulsars spin hundreds of times per second -- faster than a kitchen blender. These millisecond pulsars have been spun up and rejuvenated by accreting matter from a companion star.

"Radio astronomers discovered the first millisecond pulsar 28 years ago," said Paul Ray at the Naval Research Laboratory in Washington. "Locating them with all-sky radio surveys requires immense time and effort, and we've only found a total of about 60 in the disk of our galaxy since then. Fermi points us to specific targets. It's like having a treasure map".

Millisecond pulsars are nature's most precise clocks, with long-term, sub-microsecond stability that rivals human-made atomic clocks. Precise monitoring of timing changes in an all-sky array of millisecond pulsars may allow the first direct detection of gravitational waves -- a long-sought consequence of Einstein's relativity theory......... Posted by: Sean      Read more         Source

January 6, 2010, 8:12 AM CT

A Sun Glint on Earth

n two new videos from NASA's Deep Impact spacecraft, bright flashes of light known as sun glints act as beacons signaling large bodies of water on Earth. These observations give scientists a way to pick out planets beyond our solar system (extrasolar planets) that are likely to have expanses of liquid, and so stand a better chance of having life.

These sun glints are like sunshine glancing off the hood of a car. We can see them reflecting off a smooth surface when we are positioned in just the right way with respect to the sun and the smooth surface. On a planetary scale, only liquids and ice can form a surface smooth enough to produce the effectland masses are too roughand the surface must be very large. To stand out against a background of other radiation from a planet, the reflected light must be very bright. We won't necessarily see glints from every distant planet that has liquids or ice.

"But these sun glints are important because, if we saw an extrasolar planet which had glints that popped up periodically, we would know that we were seeing lakes, oceans or other large bodies of liquid, such as water," says Drake Deming, of NASA's Goddard Space Flight Center in Greenbelt, Md. Deming is the deputy principal investigator who leads the team that works on the Extrasolar Planet Observations and Characterization (EPOCh) part of Deep Impact's extended mission, called EPOXI. "And if we found large bodies of water on a distant planet, we would become much more optimistic about finding life"......... Posted by: Sean      Read more         Source

January 6, 2010, 8:06 AM CT

New mathematical model for early universe

Researchers have made a number of discoveries about the origins of our 13 billion-year-old universe. But a number of scientific mysteries remain. What exactly happened during the Big Bang, when rapidly evolving physical processes set the stage for gases to form stars, planets and galaxies? Now astrophysicists using supercomputers to simulate the Big Bang have a new mathematical tool to unravel those mysteries, says Daniel R. Reynolds, assistant professor of mathematics at SMU.

Reynolds collaborated with astrophysicists at the University of California at San Diego as part of a National Science Foundation project to simulate cosmic reionization, the time from 380,000 years to 400 million years after the universe was born.

Together the researchers built a computer model of events during the "Dark Ages" when the first stars emitted radiation that altered the surrounding matter, enabling light to pass through. The team tested its model on two of the largest existing NSF supercomputers, "Ranger" at the University of Texas at Austin and "Kraken" at the University of Tennessee.

The new mathematical model tightly couples a myriad of physical processes present during cosmic reionization, such as gas motion, radiation transport, chemical kinetics and gravitational acceleration due to star clustering and dark matter dynamics, Reynolds says......... Posted by: Sean      Read more         Source

December 18, 2009, 6:59 PM CT

Fog on Titan

Saturn's largest moon, Titan, looks to be the only place in the solar systemaside from our home planet, Earthwith copious quantities of liquid (largely, liquid methane and ethane) sitting on its surface. As per planetary astronomer Mike Brown of the California Institute of Technology (Caltech), Earth and Titan share yet another feature, which is inextricably linked with that surface liquid: common fog.

The presence of fog provides the first direct evidence for the exchange of material between the surface and the atmosphere, and thus of an active hydrological cycle, which previously had only been known to exist on Earth.

In a talk to be delivered December 18 at the American Geophysical Union's 2009 Fall Meeting in San Francisco, Brown, the Richard and Barbara Rosenberg Professor and professor of planetary astronomy, details evidence that Titan's south pole is spotted "more or less everywhere" with puddles of methane that give rise to sporadic layers of fog. (Technically, fog is just a cloud or bank of clouds that touch the ground).

Brown and colleagues also describe their findings in a recent paper published in The Astrophysical Journal Letters

The scientists made their discovery using data from the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft, which has been observing Saturn's system for the past five years......... Posted by: Sean      Read more         Source

December 11, 2009, 7:53 AM CT

VISTA: Pioneering new survey telescope

VISTA is the latest telescope to be added to ESO's Paranal Observatory in the Atacama Desert of northern Chile. It is housed on the peak adjacent to the one hosting the ESO Very Large Telescope (VLT) and shares the same exceptional observing conditions. VISTA's main mirror is 4.1 metres across and is the most highly curved mirror of this size and quality ever made its deviations from a perfect surface are less than a few thousandths of the thickness of a human hair and its construction and polishing presented formidable challenges.

VISTA was conceived and developed by a consortium of 18 universities in the United Kingdom [1] led by Queen Mary, University of London and became an in-kind contribution to ESO as part of the UK's accession agreement. The telescope design and construction were project-managed by the Science and Technology Facilities Council's UK Astronomy Technology Centre (STFC, UK ATC). Provisional acceptance of VISTA was formally granted by ESO at a ceremony at ESO's Headquarters in Garching, Gera number of, attended by representatives of Queen Mary, University of London and STFC, on 10 December 2009 and the telescope will now be operated by ESO.

"VISTA is a unique addition to ESO's observatory on Cerro Paranal. It will play a pioneering role in surveying the southern sky at infrared wavelengths and will find a number of interesting targets for further study by the Very Large Telescope, ALMA and the future European Extremely Large Telescope," says Tim de Zeeuw, the ESO Director General......... Posted by: Sean      Read more         Source

December 10, 2009, 10:29 PM CT

Super-massive black holes

An international team of researchers has observed four super-massive black holes at the center of galaxies, which may provide new information on how these central black hole systems operate. Their findings appear in December's first issue of the journal Astronomy and Astrophysics

These super-massive black holes at the center of galaxies are called active galactic nuclei. For the first time, the team observed a quasar with an active galactic nucleus, as part of the group of four, which is located more than a billion light years from Earth. The researchers used the two Keck telescopes on top of Mauna Kea in Hawaii. These are the largest optical/infrared telescopes in the world.

The team also used the United Kingdom Infrared Telescope (UKIRT) to follow up the Keck observations, to obtain current near-infrared images of the target galaxies.

"Astronomers have been trying to see directly what exactly is going on in the vicinity of these accreting super-massive black holes," said co-author Robert Antonucci, a UC Santa Barbara astrophysicist.

He explained that the nuclei of a number of galaxies show intense radiation from X-ray to optical, infrared, and radio, where the nucleus may exhibit a strong jet a linear feature carrying particles and magnetic energy out from a central super-massive black hole. Researchers believe these active nuclei are powered by accreting super-massive black holes. The accreting gas and dust are particularly bright in the optical and infrared regions of the electromagnetic spectrum......... Posted by: Sean      Read more         Source

December 9, 2009, 11:34 PM CT

Brightest-Ever Blazar Flare

A galaxy located billions of light-years away is commanding the attention of NASA's Fermi Gamma-ray Space Telescope and astronomers around the globe. Thanks to a series of flares that began September 15, the galaxy is now the brightest source in the gamma-ray sky -- more than ten times brighter than it was in the summer.

Astronomers identify the object as 3C 454.3, an active galaxy located 7.2 billion light-years away in the constellation Pegasus. But even among active galaxies, it's exceptional.

"We're looking right down the barrel of a particle jet powered by the galaxy's supermassive black hole," said Gino Tosti at the National Institute of Nuclear Physics in Perugia, Italy. "Some change within that jet -- we don't know what -- is likely responsible for these flares."

Blazars, like a number of active galaxies, emit oppositely directed jets of particles traveling near the speed of light when matter falls toward their central supermassive black holes. What makes a blazar so bright in gamma rays is its orientation: One of the jets happens to be aimed straight at us.

Most of the time, the brightest persistent source in the gamma-ray sky is the Vela pulsar, which at a distance of about 1,000 light-years lies practically next door.

"3C 454.3 is millions of times farther away, yet the current flare makes it twice as bright as Vela," said Lise Escande at the Center for Nuclear Studies in Gradignan, near Bordeaux, France. "That represents an incredible energy release, and one the source can't sustain for very long."........ Posted by: Sean      Read more         Source

December 8, 2009, 8:02 AM CT

NRL's MISSE7 l

The Materials on the International Space Station Experiment (MISSE) 7, designed and built by the Naval Research Laboratory (NRL), launched aboard STS-129 on November, 16, for transport to the International Space Station.

MISSE7 consists of two Passive Experiment Carriers (PEC7a and PEC7b) and three experiments mounted to the Express Pallet Assembly (ExPA). The individual experiments on MISSE7 include in situ monitoring of materials exposure, environmental monitoring including temperature, atomic oxygen exposure, and ionizing radiation. "The results will provide a better understanding of the durability of advanced materials and electronics when they are exposed to vacuum, solar radiation, atomic oxygen, and extremes of heat and cold," explains Mr. Phillip Jenkins, principal investigator. These materials and electronics, including solar cells, coatings, thermal protection, optics, sensors, and computing elements, have the potential to increase the performance and useful life of the next generation of satellites and launch systems.

NRL is responsible for the overall hardware integration and operation of MISSE7, including the power and data interfaces between the ISS and over 20 experiments included on MISSE7. NRL designed and built the power supply and thermal control system. The Communications Interface Board (CIB), which serves as the communication link between the ISS and the MISSE7 experiments, was designed, built, programmed and delivered to NRL by the Mobile And Remote Sensing (MARS) Lab at NASA GRC. Individual experiments that make up MISSE7 include researchers from NASA, DoD, DOE and university derived experiments. MISSE7 was integrated and flown under the direction of DoD's Space Test Program. NRL scientists from the Spacecraft Engineering Department and Electronics Science & Technology Division worked in conjunction on the MISSE7 project......... Posted by: Sean      Read more         Source

November 25, 2009, 8:17 AM CT

About first black holes

The first large black holes in the universe likely formed and grew deep inside gigantic, starlike cocoons that smothered their powerful x-ray radiation and prevented surrounding gases from being blown away, says a newly released study led by the University of Colorado at Boulder.

The formation process involved two stages, said Mitchell Begelman, a professor and the chair of CU-Boulder's astrophysical and planetary sciences department. The predecessors to black hole formation, objects called supermassive stars, probably started forming within the first few hundred million years after the Big Bang some 14 billion years ago. A supermassive star eventually would have grown to a huge size -- as much as tens of millions of times the mass of our sun -- and would have been short-lived, with its core collapsing in just in few million years, he said.

In the newly released study to be published in Monthly Notices of the Royal Astronomical Society in London, Begelman calculated how supermassive stars might have formed, as well as the masses of their cores. These calculations allowed him to estimate their subsequent size and evolution, including how they ultimately left behind "seed" black holes.

Begelman said the hydrogen-burning supermassive stars would had to have been stabilized by their own rotation or some other form of energy like magnetic fields or turbulence in order to facilitate the speedy growth of black holes at their centers. "What's new here is we think we have found a new mechanism to form these giant supermassive stars, which gives us a new way of understanding how big black holes may have formed relatively fast," said Begelman......... Posted by: Sean      Read more         Source

November 17, 2009, 8:33 AM CT

Hidden Details in the Birth of Super-Suns

The constellation of Orion is a hotbed of massive star formation, most prominently in the Great Nebula that sits in Orion's sword. The glowing gas of the Nebula is powered by a group of young massive stars, but behind it is a cluster of younger stars and clumps of gas. Still gathering together under gravity's pull, these gas clumps will eventually ignite into stars.

The youthful cluster cannot be seen with traditional telescopes because of the surrounding gas and dust, but a new high-resolution time-lapse movie reveals the process of massive star formation with radio images a thousand times sharper and more detailed than any previously obtained. The movie shows that massive stars form like their smaller siblings, with disk accretion and magnetic fields playing crucial roles.

The way that massive stars form remains mysterious, in part, because massive stars are rare and tend to spend their youth enshrouded by dust and gas hiding them from view.

"We know how these stars die, but not how they are born," said Lincoln Greenhill, a principal investigator of the study and part of a team comprising researchers from the Harvard-Smithsonian Center for Astrophysics (CfA) and the National Radio Astronomy Observatory (NRAO).

Unlike Hubble and other visible-light telescopes, radio telescopes can penetrate dusty veils around stars. The research astronomers studied a massive young protostar called Source I (pronounced "eye") at radio wavelengths, using the National Science Foundation's Very Long Baseline Array (VLBA) as a powerful "zoom lens."........ Posted by: Sean      Read more         Source

November 2, 2009, 11:09 PM CT

Light On Longstanding Cosmic Mystery

An international collaboration that includes researchers from the University of Delaware's Bartol Research Institute in the Department of Physics and Astronomy has discovered very-high-energy gamma rays in the Cigar Galaxy (M82), a bright galaxy filled with exploding stars 12 million light years from Earth.

The gamma rays observed by the team have energies more than a trillion times higher than the energy of visible light and are the highest-energy photons ever detected from a galaxy undergoing large amounts of star formation.

The discovery, made from data taken over a two-year-long observing campaign by the VERITAS collaboration of more than 100 researchers from 22 different institutions in the United States, Ireland, United Kingdom, and Canada, appears in the Nov. 1 advance online edition of the scientific journal Nature.

VERITAS (Very Energetic Radiation Imaging Telescope Array System) is a gamma ray observatory located at the Fred Lawrence Whipple Observatory near Amado, Ariz.

The finding provides "good evidence" that exploding stars are the origin of cosmic rays, as per Jamie Holder, assistant professor of physics and astronomy at the University of Delaware and deputy spokesperson for the VERITAS collaboration.

Produced in violent processes in our own galaxy and beyond, cosmic rays are actually energetic particles that continually bombard Earth's atmosphere. They are important, Holder says, because they make up a large fraction of the energy budget of our galaxy, The Milky Way. The amount of energy in cosmic rays is comparable to the energy contained in both starlight, and in Galactic magnetic fields, Holder notes......... Posted by: Sean      Read more         Source

October 29, 2009, 10:28 PM CT

New Celestial Map Gives Directions for GPS

A number of of us have been rescued from unfamiliar territory by directions from a Global Positioning System (GPS) navigator. GPS satellites send signals to a receiver in your GPS navigator, which calculates your position based on the location of the satellites and your distance from them. The distance is determined by how long it took the signals from various satellites to reach your receiver.

The system works well, and millions rely on it every day, but what tells the GPS satellites where they are in the first place?.

"For GPS to work, the orbital position, or ephemeris, of the satellites has to be known very precisely," said Dr. Chopo Ma of NASA's Goddard Space Flight Center in Greenbelt, Md. "In order to know where the satellites are, you have to know the orientation of the Earth very precisely."

This is not as obvious as simply looking at the Earth - space is not conveniently marked with lines to determine our planet's position. Even worse, "everything is always moving," says Ma. Earth wobbles as it rotates due to the gravitational pull (tides) from the moon and the sun. Even apparently minor things like shifts in air and ocean currents and motions in Earth's molten core all influence our planet's orientation.

Just as you can use landmarks to find your place in a strange city, astronomers use landmarks in space to position the Earth. Stars seem the obvious candidate, and they were used throughout history to navigate on Earth. "However, for the extremely precise measurements needed for things like GPS, stars won't work, because they are moving too," says Ma......... Posted by: Sean      Read more         Source

October 14, 2009, 7:08 AM CT

The Milky Way's tiny neighbor

In the new ESO image, Barnard's Galaxy glows beneath a sea of foreground stars in the direction of the constellation of Sagittarius (the Archer). At the relatively close distance of about 1.6 million light-years, Barnard's Galaxy is a member of the Local Group (ESO 11/96), the archipelago of galaxies that includes our home, the Milky Way. The nickname of NGC 6822 comes from its discoverer, the American astronomer Edward Emerson Barnard, who first spied this visually elusive cosmic islet using a 125-millimetre aperture refractor in 1884.

Astronomers obtained this latest portrait using the Wide Field Imager (WFI) attached to the 2.2-metre MPG/ESO telescope at ESO's La Silla Observatory in northern Chile. Even though Barnard's Galaxy lacks the majestic spiral arms and glowing, central bulge that grace its big galactic neighbours, the Milky Way, the Andromeda and the Triangulum galaxies, this dwarf galaxy has no shortage of stellar splendour and pyrotechnics. Reddish nebulae in this image reveal regions of active star formation, where young, hot stars heat up nearby gas clouds. Also prominent in the upper left of this new image is a striking bubble-shaped nebula. At the nebula's centre, a clutch of massive, scorching stars send waves of matter smashing into the surrounding interstellar material, generating a glowing structure that appears ring-like from our perspective. Other similar ripples of heated matter thrown out by feisty young stars are dotted across Barnard's Galaxy......... Posted by: Sean      Read more         Source

October 7, 2009, 8:44 PM CT

New aluminum-water rocket propellant

Scientists are in the process of developing a new type of rocket propellant made of a frozen mixture of water and "nanoscale aluminum" powder that is more environmentally friendly than conventional propellants and could be manufactured on the moon, Mars and other water-bearing bodies.

The aluminum-ice, or ALICE, propellant might be used to launch rockets into orbit and for long-distance space missions and also to generate hydrogen for fuel cells, said Steven Son, an associate professor of mechanical engineering at Purdue University.

Purdue is working with NASA, the Air Force Office of Scientific Research and Pennsylvania State University to develop ALICE, which was used earlier this year to launch a 9-foot-tall rocket. The vehicle reached an altitude of 1,300 feet over Purdue's Scholer farms, about 10 miles from campus.

"It's a proof of concept," Son said. "It could be improved and turned into a practical propellant. Theoretically, it also could be manufactured in distant places like the moon or Mars instead of being transported at high cost".

Findings from spacecraft indicate the presence of water on Mars and the moon, and water also may exist on asteroids, other moons and bodies in space, said Son, who also has a courtesy appointment as an associate professor of aeronautics and astronautics......... Posted by: Sean      Read more         Source

October 6, 2009, 7:00 AM CT

The female astronaut

In the early years of the "space race" (1957-1975) two men sought to test a scientifically simple yet culturally complicated theory: that women might be innately better suited for space travel than men. In 1960 the thought of a woman in space was a radical one, and justifiably so. On the ground 75% of American women did not work outside the home and females were banned from military flight service altogether. In marriage, wives were mandatory to have their husband's permission to take out a bank loan, buy property, or purchase large household goods such as a refrigerator. Despite the social odds, a Harvard-educated surgeon and a U.S. Air Force General sought to determine if, from a purely practical perspective, women were suitable for space flight.

The latest look at the intersection of physiology, spaceflight and politics is captured in a new article entitled "A Forgotten Moment in Physiology: The Lovelace Woman in Space Program (1960-1962)," written by Kathy Ryan, Jack Loeppky and Donald Kilgore*. Their article appears in the September edition of Advances in Physiology (http://advan.physiology.org/cgi/reprint/33/3/157), a publication of the American Physiological Society (APS; www.the-aps.org/press). The APS has been an integral part of the scientific discovery process since it was founded in 1887......... Posted by: Sean      Read more         Source

September 30, 2009, 6:46 AM CT

Cosmic Rays Hit Space Age High

Planning a trip to Mars? Take plenty of shielding. As per sensors on NASA's ACE (Advanced Composition Explorer) spacecraft, galactic cosmic rays have just hit a Space Age high.

"In 2009, cosmic ray intensities have increased 19% beyond anything we've seen in the past 50 years," says Richard Mewaldt of Caltech. "The increase is significant, and it could mean we need to re-think how much radiation shielding astronauts take with them on deep-space missions".

The cause of the surge is solar minimum, a deep lull in solar activity that began around 2007 and continues today. Scientists have long known that cosmic rays go up when solar activity goes down. Right now solar activity is as weak as it has been in modern times, setting the stage for what Mewaldt calls "a perfect storm of cosmic rays".

"We're experiencing the deepest solar minimum in nearly a century," says Dean Pesnell of the Goddard Space Flight Center, "so it is no surprise that cosmic rays are at record levels for the Space Age".

Galactic cosmic rays come from outside the solar system. They are subatomic particles--mainly protons but also some heavy nuclei--accelerated to almost light speed by distant supernova explosions. Cosmic rays cause "air showers" of secondary particles when they hit Earth's atmosphere; they pose a health hazard to astronauts; and a single cosmic ray can disable a satellite if it hits an unlucky integrated circuit......... Posted by: Sean      Read more         Source

September 23, 2009, 7:19 AM CT

First Full Simulation of Star's Final Hours

The precise conditions inside a white dwarf star in the hours leading up to its explosive end as a Type Ia supernova are one of the mysteries confronting astrophysicists studying these massive stellar explosions. But now, a team of researchers, composed of three applied mathematicians at the U.S. Department of Energy's (DOE) Lawrence Berkeley National Laboratory and two astrophysicists, has created the first full-star simulation of the hours preceding the largest thermonuclear explosions in the universe.

In a paper to be reported in the recent issue of Astrophysical Journal, Ann Almgren, John Bell and Andy Nonaka of Berkeley Lab's Computational Research Division, with Mike Zingale of Stony Brook University and Stan Woosley of University of California, Santa Cruz, describe the first-ever three-dimensional, full-star simulations of convection in a white dwarf leading up to ignition of a Type Ia supernova. The project was funded by the DOE Office of Science.

Type Ia supernovae are of particular interest to astrophysicists as they are all thought to besurprisingly similar to each other, leading to their use as "standard candles" which researchers use to measure the expansion of the universe. Based on observations of these massive stellar explosions-a single supernova is as bright as an entire galaxy-researchers believe our universe is expanding at an accelerating rate. But what if Type Ia supernovae have not always exploded in the same way? What if they aren't standard?........ Posted by: Sean      Read more         Source

September 20, 2009, 7:04 PM CT

More to Solar Cycle than Sunspots

Challenging conventional wisdom, new research finds that the number of sunspots provides an incomplete measure of changes in the sun's impact on Earth over the course of the 11-year solar cycle. The study, led by researchers at the National Center for Atmospheric Research (NCAR) and the University of Michigan, finds that Earth was bombarded last year with high levels of solar energy at a time when the sun was in an uncommonly quiet phase and sunspots had virtually disappeared.

"The sun continues to surprise us," says main author Sarah Gibson of NCAR's High Altitude Observatory. "The solar wind can hit Earth like a fire hose even when there are virtually no sunspots".

The study, also written by researchers at NOAA and NASA, is being published recently in the Journal of Geophysical Research. It was funded by NASA and by the National Science Foundation, NCAR's sponsor.

"It is vitally important to realize that the 'quiet' sun really isn't all that quiet," says Rich Behnke, program director in NSF's Division of Atmospheric Sciences. "These high-speed streams of wind can affect a number of of our communications and navigation systems. And they can come at any time, during any part of the solar cycle".

Researchers for centuries have used sunspots, which are areas of concentrated magnetic fields that appear as dark patches on the solar surface, to determine the approximately 11-year solar cycle. At solar maximum, the number of sunspots peaks. During this time, intense solar flares occur daily and geomagnetic storms frequently buffet Earth, knocking out satellites and disrupting communications networks......... Posted by: Sean      Read more         Source