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Yeast In Space
Cell-directed assembly - lead author Helen Baca
The sample devices are riding on the International Space Station (courtesy of Sandia National Laboratories and the University of New Mexico, NASA and US Air Force) to test whether nanostructures whose formations were directed by yeast and other single cells can create more secure homes for their occupants - even in the vacuum and radiation of outer space - than those created by more standard chemical procedures. Sandia is a National Nuclear Security Administration laboratory. "Cheap, tiny, and very lightweight sensors of chemical or biological agents could be made from long-lived cells that require no upkeep, yet sense and then communicate effectively with each other and their external environment," says former UNM graduate student and Sandia consultant Helen Baca, lead author on the paper. Baca was advised by Sandia Fellow and UNM professor of chemical engineering, molecular genetics & microbiology Jeff Brinker. Groups of such long-lived cells may also serve as models to investigate how tuberculosis bacteria survive long periods of dormancy within human bodies. En masse, they also may be used to generate signals to repel harmful bacteria from the surfaces of surgical tools like catheters......... Posted by: Brooke Permalink Nuclear explosion on a dead star
During the night of 12 February this year Japanese astronomers reported that a star called RS Ophiuchi had suddenly brightened and become clearly visible in the night sky. Although this was the latest in a series of such outbursts that have been spotted over the last hundred years or so, it was the first since 1985 and therefore an opportunity to bring to bear new, more powerful, telescopes in an effort to understand the causes and consequences of these eruptions. Dr Tim OBrien of The University of Manchesters Jodrell Bank Observatory requested urgent observations with the VLBA (the Very Long Baseline Array of radio telescopes extending from Hawaii to the Caribbean). Our first observations, made only two weeks after the explosion was reported, showed an expanding blast wave already comparable in size to Saturns orbit around the Sun. However, we needed to use the worlds most powerful radio telescopes because, from a distance of 5,000 light years, its apparent size on the sky was only 5 millionths of a degree the size of a football seen from 2,700 km (1,700 miles) away......... Posted by: Brooke Permalink Source Cluster Hits The Magnetic Bull's-eye
Credits: Dr. Xiao/Chinese Academy of Sciences (Beijing)
This is the first time such an observation has been made and gives astronomers a unique insight into the physical process responsible for the most powerful explosions that can occur in the Solar System: the magnetic reconnection. When looking at the static pattern of iron filings around a bar magnet, it is difficult to imagine how changeable and violent magnetic fields can be in other situations. In space, different regions of magnetism behave somewhat like large magnetic bubbles, each containing electrified gas known as plasma. When the bubbles meet and are pushed together, their magnetic fields can break and reconnect, forming a more stable magnetic configuration. This reconnection of magnetic fields generates jets of particles and heats the plasma. At the very heart of a reconnection event, there must be a three dimensional zone where the magnetic fields break and reconnect. Researchers call this region the null point but, until now, have never been able to positively identify one, as it requires at least four simultaneous points of measurements......... Posted by: Brooke Permalink Source Black Holes At The Center Of Galaxies?
Cosmologists know that most galaxies host a compact, supermassive object at their centre and they believe these must be black holes. Such a black hole is believed to be responsible for the X-ray flares coming from the middle of our galaxy, which would be caused by the black hole devouring surrounding matter. But recent observations show that these flares fire roughly every 20 minutes - a regularity that is hard to explain in terms of the behaviour of a black hole. Now Anatoly Svidzinsky, a physicist at Texas A&M University in College Station, Texas, thinks that hypothetical particles called axions could solve the mystery. Axions have very little mass and no electric charge, and they barely interact with other particles. They were originally proposed to fix a problem with the strong force in particle physics, but have more recently been considered as possible candidates for dark matter, the unseen stuff thought to make up nearly 90 per cent of a galaxy's mass. In the 1990s, computer simulations of clouds of dark matter made of axions showed that giant bubbles of these particles would burst out from the clouds. Svidzinsky thinks that such bubbles exist at the centre of galaxies. His model shows that the axion bubbles would expand and contract with a period of 20 minutes - matching the period of infrared and X-ray flares from Sagittarius A*, the location of the supermassive compact object at the centre of our galaxy. The model predicts that stable axion bubbles would weigh between about 1 million and 2.5 billion times the mass of the sun - exactly the mass range observed for compact objects at the centres of galaxies (www.arxiv.org/ astro-ph/0607179)......... Posted by: Brooke Permalink Source Flying over the cloudy world
Global dynamics of Venus northern hemisphere
If taking the first ever clear images of the double-eye vortex at Venus' south pole - imaged by Venus Express during its very first orbit - was already a first in the history of planetary exploration and a very pleasant surprise for the scientists, nobody could expect that the vortex had a structure even more complicated than possibly foreseen. Infrared images taken by the Ultraviolet/Visible/Near-Infrared spectrometer (VIRTIS) on board the spacecraft not only provided the first clear view of the vortex, but also gave a much closer insight into it when Venus Express flew over the south pole at the end of May this year. VIRTIS is an instrument that can operate at different wavelengths. Each infrared wavelength provides a view of the Venusian atmosphere at a different altitude, like a 'cross-section'. "When we looked at this gigantic vortex at different depths, we realised how much its shape is varying over altitude," said Pierre Drossart, VIRTIS co-Principal Investigator, from the Observatoire de Paris, France. "It is like if we were looking at different structures, rather than a single one. And the new data we have just started gathering and analysing reveal even stronger differences"......... Posted by: Brooke Permalink Source Gassendi crater
This mosaic of two images, taken by the advanced Moon Imaging Experiment (AMIE) on board ESA’s SMART-1 spacecraft, shows the inside of crater Gassendi on the Moon.
AMIE obtained these images on 13 January 2006, one minute apart from each other, from a distance of about 1220 kilometres (top frame) and 1196 kilometres (bottom frame) from the surface, with a ground resolution of 110 and 108 metres per pixel, respectively. The area shown in the top image is centred at a latitude of 16.2º South and longitude 40.2º West, while the bottom images is centred at a latitude of 17.9º South and longitude 40.2º West. Gassendi is an impact feature located on the near side of the Moon, at the northern edge of Mare Humorum. The crater is actually much larger than the field of view visible in this image. The hills on the lower right of the mosaic are the central peak of the crater, with a height of roughly 1.2 kilometres. The crater almost fully visible on the top is called 'Gassendi A'. Gassendi is a scientifically interesting site because it offers lunar landers the possibility of sampling ancient highland rocks (in the crater's central peak) as well as providing ages for both the Humorum impact basin and the Gassendi crater itself. However, because the terrain just outside the crater is quite rough, if a crew landed in this region, it would be pretty difficult to reach Gassendi's central peaks for sampling. Gassendi was considered as one of the three potential sites for the Apollo 17 mission, that eventually touched ground in the Taurus-Littrow valley......... Posted by: Brooke Permalink Source Supernova And A Mysterious Object
Puzzling pulsation from the heart of RCW103
The object is in the heart of supernova remnant RCW103, the gaseous remains of a star that exploded about 2 000 years ago. Taken at face value, RCW103 and its central source would appear to be a textbook example of what is left behind after a supernova explosion: a bubble of ejected material and a neutron star. A deep, continuous 24.5-hour observation has revealed something far more complex and intriguing, however. The team, from the Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF) of the Istituto Nazionale di Astrofisica (INAF) in Milan, Italy, has found that the emission from the central source varies with a cycle that repeats itself every 6.7 hours. This is an astonishingly long period, tens of thousands of times longer than expected for a young neutron star. Also, the object's spectral and temporal properties differ from an earlier XMM-Newton observation of this very source in 2001. "The behaviour we see is especially puzzling in view of its young age, less than 2 000 years," said Andrea De Luca of IASF-INAF, the lead author. "It is reminiscent of a multimillion-year-old source. For years we have had a sense that the object is different, but we never knew how different until now."........ Posted by: Brooke Permalink Source cracking the secret codes of Galileo satellite
Mark Psiaki, left, professor of mechanical and aerospace engineering, hooks up an experimental GPS/Galileo digital storage receiver and patch antenna with the assistance of graduate students Todd Humphreys, center, and Shan Mohiuddin in Rhodes Hall. Copyright © Cornell Universit
Jason Koski/University Photography The codes and the methods used to extract them were reported in the recent issue of GPS World. The navigational satellite, GIOVE-A (Galileo In-Orbit Validation Element-A), is a prototype for 30 satellites that by 2010 will compose Galileo, a $4 billion joint venture of the European Union, European Space Agency and private investors. Galileo is Europe's answer to the United States' GPS. Because GPS satellites, which were put into orbit by the Department of Defense, are funded by U.S. taxpayers, the signal is free -- consumers need only purchase a receiver. Galileo, conversely, must make money to reimburse its investors -- presumably by charging a fee for PRN codes. Because Galileo and GPS will share frequency bandwidths, Europe and the United States signed an agreement whereby some of Galileo's PRN codes must be "open source." Nevertheless, after broadcasting its first signals on Jan. 12, 2006, none of GIOVE-A's codes had been made public......... Posted by: Brooke Permalink Source Earth Observation Satellites And Polar Year 2007-2008
Having access to near-continuous satellite data of these regions over long periods of time is important for researchers to identify and analyse long-term climatic trends and changes. ESA will provide current and historical data, dating back 15 years, from its ERS-1, ERS-2 and Envisat satellites as well as data collected from many non-ESA satellites. Dr. David Carlson, Director of the International Programme Office for the Polar Year, predicts a number of uses of satellite data: "A number of scientists use satellite data as part of their daily activities. During IPY those scientists will push to extract more and more information from the satellites, especially to understand recent and current distributions of snow and ice. We will use every form of satellite data - passive visual, active microwave, and even sensitive gravity measurements - to understand changes in the global ice sheets". Since their advent satellites have contributed to a greater understanding of polar regions, helped identify the strong links these regions have with Earth's terrestrial, ocean and atmospheric processes and made startling observations. For example, within days of its launch in 2002, ESA's environmental satellite Envisat captured the disintegration of the Larsen-B ice shelf in Antarctica, surprising researchers because of the rapid rate at which the shelf broke apart......... Posted by: Brooke Permalink Source Space Shuttle Launch Countdown Begins
NASA reports that good imagery of all areas of the strut and bracket were acquired using a special visual inspection device (borescope) which provides a high level of confidence in the integrity of the remaining strut insulation. The aero thermal loads were concluded to be within the acceptable limits. An ice liberation test concluded that no excessive ice build-up nor ice shedding is expected in/from the damaged area. The third launch attempt of Space Shuttle Discovery on flight STS-121 is scheduled for 20:38 CEST (18:38 UT) today......... Posted by: Brooke Permalink Source |
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