- Astronomers Reveal the Hidden Surface of Venus
- Intergalactic GPS Will Guide You through the Stars
- Sun Emits a Mid-Level Solar Flare
- Carina Nebula Survey Reveals Details of Star Formation
- The World’s Largest Radio Telescope Takes a Major Step Towards Construction
- JAXA Advances in Space-Based Solar Power
- Testing Astronauts' Lungs in Space Station Airlock
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Posted: 10 Mar 2015 12:19 AM PDT
From earthbound optical telescopes, the surface of Venus is shrouded beneath thick clouds made mostly of carbon dioxide. To penetrate this veil, probes like NASA’s Magellan spacecraft use radar to reveal remarkable features of this planet, like mountains, craters, and volcanoes. Recently, by combining the highly sensitive receiving capabilities of the National Science Foundation’s (NSF) Green Bank Telescope (GBT) and the powerful radar transmitter at the NSF’s Arecibo Observatory, astronomers were able to make remarkably detailed images of the surface of this planet without ever leaving Earth. The radar signals from Arecibo passed through both our planet’s atmosphere and the atmosphere of Venus, where they hit the surface and bounced back to be received by the GBT in a process known as bistatic radar.
This capability is essential to study not only the surface as it appears now, but also to monitor it for changes. By comparing images taken at different periods in time, scientists hope to eventually detect signs of active volcanism or other dynamic geologic processes that could reveal clues to Venus's geologic history and subsurface conditions.
High-resolution radar images of Venus were first obtained by Arecibo in 1988 and most recently by Arecibo and GBT in 2012, with additional coverage in the early 2000s by Lynn Carter of NASA's Goddard Spaceflight Center in Greenbelt, Md. The first of those observations was an early science commissioning experiment for the GBT.
“It is painstaking to compare radar images to search for evidence of change, but the work is ongoing. In the meantime, combining images from this and an earlier observing period is yielding a wealth of insight about other processes that alter the surface of Venus,” said Bruce Campbell, Senior Scientist with the Center for Earth and Planetary Studies at the Smithsonian’s National Air and Space Museum in Washington, D.C. A paper discussing the comparison between these two observations was accepted for publication in the journal Icarus.
The 100-meter Green Bank Telescope is the world's largest fully steerable radio telescope. Its location in the National Radio Quiet Zone and the West Virginia Radio Astronomy Zone protects the incredibly sensitive telescope from unwanted radio interference, enabling it to perform unique observations.
The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
Credit: nrao.edu
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Posted: 09 Mar 2015 04:04 PM PDT
Lost in the Universe? Need some precise navigation through the bulk of stars in the night sky? Don’t worry, there will be an instrument for that - the Multi-Object Optical and Near-infrared Spectrograph (MOONS) at the European Southern Observatory’s (ESO) Very Large Telescope (VLT) in northern Chile. The spectrograph, dubbed the intergalactic GPS, will help us navigate through the billions of stars in our galaxy and create a comprehensive map of its structure. “One of the first science cases is to help build up maps of the central region of our galaxy,” William Taylor of the UK Astronomy Technology Centre (UK ATC) in Edinburgh, UK, told astrowatch.net. “With infrared light we have the power to see through the dust that obscures many of the objects in the central region of our galaxy, and so we can map the speeds and types of stars in the central bulge of the Milky Way.”
The MOONS project is led by a team from UK ATC and the Royal Observatory in Edinburgh. The UK ATC will lead the Project Office managing the multinational consortium that will construct MOONS, and will also play a vital design role for key components.
“There’s a host of different countries building parts of MOONS; Italy, France, Switzerland, Portugal and Chile,” Taylor said. “The UK is leading the project and will be responsible for putting it all together here in Edinburgh before shipping it south to Chile. The other major UK partner in building the thing is the University of Cambridge.”
MOONS is a large field (500 square arcminutes), multi-object (500 object + 500 sky fibers) instrument with spectral resolution of 5000 and 20 000 proposed for the VLT Nasmyth focus. It will allow astronomers to see obscured areas in the Milky Way at a distance of around 40,000 light years away, and enable them to create a 3D map of our galaxy.
“It can record spectra of many objects simultaneously. It does this by using small robotic arms to position 1000 fibers at the back of the telescope. The optical fibers connected to the VLT feed the light into a van-sized spectrograph. Once in the spectrograph, the light is split into its constituent parts, much like water droplets can split sunlight into its constituent colors and form a rainbow,” Taylor explained. “MOONS will look at light from objects that extends from what our eyes see as red, to the region of the infrared, where our eyes seize to be sensitive.”
MOONS will use the color of light emitted by objects to reveal their chemical composition, mass, speed and other properties. Breaking new ground by simultaneously observing 1000 objects using fiber-optic cables to feed their visible and infrared light into the instrument, it will survey large samples of objects far faster than any existing instrument and conduct surveys that would be virtually impossible using today’s technologies.
Michele Cirasuolo of the UK ATC, the Principal Investigator of the MOONS project revealed that the instrument would be able to pioneer a wide range of galactic, extragalactic and cosmological studies and provide crucial follow-up for major facilities such as ESA’s Gaia mission, the Visible and Infrared Survey Telescope for Astronomy (VISTA), Euclid spacecraft and the Large Synoptic Survey Telescope (LSST).
MOONS will complement the ongoing and planned surveys including the new large Gaia-ESO public spectroscopic survey. The unique features of MOONS will clarify the nature of the extinct regions of the Bulge, but will also assess the chemo-dynamical structure of the Thin and Thick Disc, understand the importance of satellites and streams in the Halo, ultimately creating an accurate 3D map of our Galaxy to provide essential insight into its origin and evolution.
MOONS will also be a powerful instrument to unveil ‘the redshift desert’ and study this crucial epoch around the peak of star-formation, the assembly of the most massive galaxies, the effect of the environment and the connection with the shining of powerful active nuclei.
“We will also use MOONS to study distant galaxies. On large scales we evidence for the alignment of galaxies, knowledge of which helps us to understand what our Universe is made of. Due to the expansion of the Universe, light emitted from the more distant galaxies is red-shifted into the infrared and so we really need something like MOONS to map out large portions of the galaxy,” Taylor noted.
The instrument is scheduled to become operational by 2019. Once MOONS is up and running, the international consortium will receive 300 nights of observations using the instrument. In particular, this will benefit two ground-breaking projects: one to produce an unprecedented sophisticated survey of the center of the Milky Way; the other to look far back in time at ultra-distant galaxies to uncover the secrets of their early evolution.
“In terms of exploiting the science that we can do with MOONS, we have interest from a whole host of UK universities - over 14 at the last count. When the UK invests in building an instrument like this, we get a number of guaranteed nights on the telescope in return. With the consortium’s 300 nights on one of the world’s largest telescopes we have the potential to do some huge surveys, with millions of objects,” Taylor said. “The data from this instrument is going to keep UK scientists busy for many years to come.”
Taylor also underlined the uniqueness of MOONS: “There are systems that gather light from lots of objects, but only in the visible wavelengths of light. Equally, there are some devices that gather light from a few objects in the infrared. MOONS will be the first to do both. Well, maybe the first - the Japanese are building something similar to go on their telescope in Hawaii. I’m not saying it is a race, but we’d like to be first! The trouble is IR instruments are generally more expensive than visible ones, and so things like MOONS are rare beasts,” he concluded.
The MOONS project brings together scientists and engineers in a consortium led by the Science and Technology Facilities Council – UK ATC, Royal Observatory, Edinburgh, UK; and including CAAUL – Centre for Astronomy and Astrophysics of University of Lisbon, Portugal; GEPI, Observatoire de Paris, France; Italian National Institute for Astrophysics (INAF) with its centers in Florence, Bologna, Milan and Rome, Italy; AIUC, Centre for Astro-Engineering, Pontificia Universidad Católica de Chile, Santiago Chile; Cavendish Laboratory and Institute of Astronomy, University of Cambridge, United Kingdom; ETH Zürich, Institute for Astronomy, Switzerland; the University of Geneva, through its Astronomical Observatory, Sauverny, Switzerland and ESO.
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Posted: 09 Mar 2015 02:04 PM PDT
The sun emitted a mid-level solar flare, peaking at 5:22 pm EST on March 7, 2015, which resulted in an impressive coronal mass ejection (CME). This flare is classified as an M9.2-class flare. Forecasters have analyzed and modeled this CME and determined that this event will miss the Earth and is directed east of the Sun-Earth line. NASA’s Solar Dynamics Observatory, which watches the sun constantly, captured an image of the event. More flares are in the offing. Active Region 2297 has developed a 'beta-gamma-delta' magnetic field that harbors energy for X-class solar flares. NOAA forecasters estimate a 10% chance of such an explosion on March 9th.
Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however -- when intense enough -- they can disturb the atmosphere in the layer where GPS and communications signals travel.
M-class flares are a tenth the size of the most intense flares, the X-class flares. The number provides more information about its strength. An M2 is twice as intense as an M1, an M3 is three times as intense, etc.
Radiation from Saturday's flare ionized the upper layers of Earth's atmosphere on the dayside of the planet. This caused a moderate HF radio blackout over the Pacific Ocean. Mariners and hams operating at frequencies below 10 MHz would likely have noticed disturbed and/or attenuated signals.
A slight chance for an S1 or greater solar radiation storm exists due to the potential of significant flare activity from Region 2297.
No G1 (Minor) or greater geomagnetic storms are expected. Unsettled to active periods (Below G1-Minor) are expected over the next two days due to coronal hole high speed stream activity.
To see how this event may affect Earth, please visit NOAA's Space Weather Prediction Center athttp://spaceweather.gov, the U.S. government's official source for space weather forecasts, alerts, watches and warnings.
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Posted: 09 Mar 2015 01:35 PM PDT
A new Rice University-led survey of one of the most active star-forming regions in the galactic neighborhood is helping astronomers better understand the processes that may have contributed to the formation of the sun 4.5 billion years ago. The survey of Carina Nebula is available online in the Astronomical Journal. “Most stars form in giant molecular clouds, regions where the density of matter is sufficient for hydrogen atoms to pair up and form H2 molecules,” said Patrick Hartigan, professor of physics and astronomy at Rice and lead author of the new study. “The Carina Nebula is an ideal place to observe how this happens because there are dozens of examples of forming stars at various stages of development.”
The Carina Nebula spans more than 100 light-years and is visible to the naked eye as a bright glowing patch in the Milky Way for observers in the Southern Hemisphere. In addition to thousands of stars similar in mass to the sun, Carina contains more than 70 O-type stars, each with a mass between 15 and 150 times that of the sun. O-stars burn hot and bright and die young, typically within 10 million years. These massive stars play a key role in how less-massive, solar-type stars in the same region evolve because O-stars evaporate and disperse dust and gas that might otherwise collect in a disk to form planets around the low-mass stars.
Hartigan said O-stars also have a profound influence on their parent molecular clouds.
“Ultraviolet radiation from these hot, massive stars ionizes molecular hydrogen, and as the radiation evaporates the molecular cloud, O-stars carve beautiful pillars and clear the space around smaller stars that exist nearby,” Hartigan said.
A famous example of these pillars is found in the Eagle Nebula and was the subject of the “Pillars of Creation,” one of the most-recognized images from the Hubble Space Telescope.
Hartigan said the sculpting process that creates such pillars marks one stage of the destruction of a molecular cloud. In the first stage, the outer wall of the cloud appears largely unbroken. Fat pillars form first and are steadily eroded into skinny pillars that eventually become isolated globules that are disconnected from the receding wall. Often, a young star with a disk is present at the apex of a pillar or within a globule. The entire evaporation process takes about a million years, and astronomers believe it is an essential aspect in the creation of solar systems like our own, Hartigan said.
The Carina star-formation region is about 7,500 light-years from Earth, about five times farther away than the Orion Nebula, which is visible in the northern hemisphere but is only about one-tenth the size of the Carina Nebula.
The new images of Carina show multiple examples of each of the different stages of cloud destruction.
“There is huge variety in Carina, in part because it is so large,” Hartigan said. “It spans more than a degree on a side, which means that it covers more of the sky than four full moons. In addition, Carina is young enough to have a great deal of ongoing star formation. But it is also old enough that the most massive stars have cleared away enough material to reveal a dizzying array of globules and pillars.”
In the new survey, Hartigan and colleagues Megan Reiter and Nathan Smith of the University of Arizona and John Bally of the University of Colorado used the National Optical Astronomy Observatory’s Extremely Wide-Field Infrared Imager and its Mosaic camera to photograph the entire Carina region from the four-meter Blanco telescope at Cerro Tololo in northern Chile. Both the optical and near-infrared imagers use large-format detectors to obtain high-resolution shots of wide swaths of the sky. Each of the images isolates a specific wavelength of infrared or optical light. By looking at these wavelengths separately and in composite, Hartigan and colleagues were able to penetrate Carina’s nebular dust and hone in the pillar-carving processes caused by O-type stars.
Hartigan said numerical simulations in recent decades have suggested that strong stellar winds from O-stars also induce star formation by compressing material in a molecular cloud to the point where it becomes gravitationally unstable, a process known as triggering. He said the new images reveal important constraints on this process.
“We observe two star clusters in which the pillars are being carved both from within, by young, newly formed stars inside the pillar, and from without by O-type stars,” Hartigan said. “It appears that the stars in the cluster already existed before the O-stars evaporated the cloud material, which implies that triggering did not create these clusters.”
While many of the pillars, globules and other structures that were detailed in the study were previously known to astronomers, Hartigan said the new images reveal details about the underlying physics of the region.
“Our images are sharper and deeper than previous ones, and they provide the best snapshot so far of a massive star-formation region at one point in time,” he said.
The research was supported by the Department of Energy.
Credit: rice.edu
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Posted: 09 Mar 2015 01:10 PM PDT
At their meeting last week at the Square Kilometre Array (SKA) Organisation Headquarters near Manchester, UK, the SKA Board of Directors unanimously agreed to move the world’s largest radio telescope forward to its final pre-construction phase. The design of the €650M first phase of the SKA (SKA1) is now defined, consisting of two complementary world-class instruments – one in Australia and one in South Africa – both expecting to deliver exciting and transformational science. “I was impressed by the strong support from the Board and the momentum to take the project forward”, said Professor Philip Diamond, Director General of the SKA Organisation. “The SKA will fundamentally change our understanding of the Universe. We are talking about a facility that will be many times better than anything else out there.”
Presently in its design phase, the international project, currently consisting of 11 nations, has been engaged over the last 20 months in a rigorous and extremely challenging science-driven, engineering process with teams from around the world working to refine the design of SKA1.
The SKA instruments will be located in two countries – South Africa and Australia. In the first phase of the project, South Africa will host about 200 parabolic antennas or dishes – similar to, but much larger than a standard domestic satellite dish – and Australia more than 100,000 ‘dipole’ antennas, which resemble domestic TV aerials.
“Thanks to these two complementary instruments, we will address a broad range of exciting science, such as observing pulsars and black holes to detect the gravitational waves predicted by Einstein, testing gravity, and looking for signatures of life in the galaxy”, said Professor Robert Braun, Science Director of the SKA Organisation. “We will also observe one of the last unexplored periods in the history of our Universe – the epoch of re-ionisation – looking back to the first billion years of the Universe at a time when the first stars and galaxies are forming.”
The Australian SKA Pathfinder (ASKAP) telescope, a precursor telescope already operating as a first-class instrument in its own right in Western Australia, will continue to provide world-leading survey capability which will complement the overall SKA programme. The SKA will incorporate a programme for the development of next-generation Phased Array Feeds (PAFs), a technology that greatly enhances the field of view of radio telescopes, allowing for observations of a larger portion of the sky in any given time. In South Africa, the MeerKAT telescope, another precursor to the SKA, will be integrated into the dish array.
“This will build on South Africa’s considerable investment in science and in particular radio astronomy, it’s something we can rightly be very proud of”, said Dr Phil Mjwara, Director General of the South African Department of Science and Technology. “Being involved in this exciting global science project spanning two continents alongside our Australian colleagues and colleagues from around the world is great for the country and for the African continent.”
“The Australian astronomical community are delighted to be working with their colleagues from around the world in one of the most thrilling science endeavours of the 21st century”, said Professor Brian Boyle, Australia’s SKA Director. “This outcome recognises the confidence the global community has placed in the world-class observatory we have built in Western Australia and the leading-edge radio-astronomy technology Australia has developed for the pathfinder telescopes located there.”
“The next step is to work with the SKA partner countries to develop an international Organisation before the start of the construction in 2018”, said Professor John Womersley, Chair of the SKA Board of Directors. “This incredible telescope has a design, it is within budget, construction is around the corner, it will drive technology development in the era of Big Data, and it is going to deliver Nobel prize-winning science. In short, it will have an invaluable impact on society like very few enterprises before it.”
The Square Kilometre Array (SKA) project is an international effort to build the world’s largest radio telescope, led by the SKA Organisation from Jodrell Bank Observatory in the UK. The SKA will conduct transformational science to improve our understanding of the Universe and the laws of fundamental physics, monitoring the sky in unprecedented detail and mapping it hundreds of times faster than any current facility.
The SKA is not a single telescope, but a collection of telescopes or instruments, called an array, to be spread over long distances. The SKA is to be constructed in two phases: Phase 1 (called SKA1) in South Africa and Australia; Phase 2 (called SKA2) expanding into other African countries, with the Australian component also being expanded.
Already supported by 11 member countries – Australia, Canada, China, Germany, India, Italy, New Zealand, South Africa, Sweden, The Netherlands and the United Kingdom – the Organisation has brought together some of world’s finest scientists, engineers and policy makers and more than 100 companies and research institutions across 20 countries in the design and development of the telescope. Construction of the SKA is set to start in 2018, with early science observations in 2020.
Credit: skatelescope.org
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Posted: 09 Mar 2015 12:55 PM PDT
Japan’s space agency has successfully transmitted electricity converted into microwaves in an experiment that moves the world closer to receiving energy generated by orbiting solar panels. The experiment was conducted March 8 by the Japan Aerospace Exploration Agency (JAXA) and other organizations at Mitsubishi Electric Corp.’s outdoor testing ground in Hyogo Prefecture. The researchers fine-tuned their equipment to transmit the microwaves to a receiving antenna over a distance of about 55 meters.
"Being able to control microwaves is an important technology in transmitting electricity safely and without loss," said Kazuo Ohashi, director of JAXA's Advanced Mission Research Group. "The successful test was a big step for us."
Although there are still many remaining obstacles, such as the massive costs associated with setting up such a system, JAXA and partners estimate that a solar panel in orbit with a diameter of two to three kilometers could generate a gigawatt of electricity, equivalent to the power created by a nuclear reactor.
Having solar power generated in outer space has the advantage of the operation being unaffected by weather or nightfall.
Because powerful microwaves are potentially harmful and dangerous to humans and the environment, the direction to which the beam is emitted has to be precisely controlled.
JAXA is developing what it calls the Space Solar-Power System, which is designed to transmit electricity generated by solar arrays back to Earth by converting the energy into microwaves or other beams.
Research on such a system first took off in Japan in the 1980s.
Credit: ajw.asahi.com
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Posted: 09 Mar 2015 12:17 PM PDT
The International Space Station’s air lock was pumped free of air for the first time in the name of science last week. Inside the cylindrical Quest airlock, ESA astronaut Samantha Cristoforetti and NASA’s Terry Virts monitored their breathing for researchers back on Earth. With each lungful of air, our bodies absorb oxygen and exhale waste-product molecules such as carbon dioxide and the important ‘signalling’ molecule nitric oxide. The Airway Monitoring experiment looks at the amount of nitric oxide the astronauts expelled by the astronauts in the airlock. Nitric oxide is a gas found in cigarette smoke and car exhaust, for example, and it is produced in our bodies to regulate blood vessels and act as an antibacterial agent.
Doctors measure the amount of nitric oxide exhaled by patients to help diagnose inflamed lungs and asthma.
On Earth, dust drifts to the floor where vacuum cleaners or a damp cloth remove it easily. In weightlessness, dust circulates freely and often irritates and inflames eyes and lungs.
In addition, dust on the Moon and probably Mars sticks to astronauts through static electricity and has sharp edges – all making it more likely that dust will enter astronauts’ lungs and do harm.
The Airway Monitoring experiment will test the use of nitric oxide as a tool to monitor lung inflammation as well as charting lung health in astronauts.
Four sessions will see the pair exhale into the equipment. Samantha and Terry made their first contributions before flight at NASA and ran their first space session in space in January.
On Friday, they entered the Station’s Quest airlock for their last run and reduced the pressure by 30% – equivalent to being on a mountain at 3000 m altitude.
They are the first of eight astronauts to collect data on their lungs for this experiment. It is also the first time that Quest is used for scientific purposes – the module was installed to allow astronauts to venture outside on spacewalks.
Testing the nitric oxide diagnostic technique in space adds to the data for use on Earth. More than 300 million people suffer from asthma, so a quick and simple lung test would be of great benefit.
Lars Karlsson, lead investigator for this experiment from the Karolinska Institutet of Sweden, is hopeful that the experiment in the airlock will open up new fields of research in reduced pressure in space: “In the future, it is quite likely that drugs could be designed based on exhaled nitric oxide measurements, to find the most effective molecules to treat inflamed airways and lungs. This type of research is a first step down this road.”
Credit: ESA
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