Singing Stars May Be a Reality in the Universe

Scientists may have discovered the "sound" of stars by observing fluid in motion.

""A team of researchers observed the reaction of an ultra-intense laser with a plasma target, theUniversity of York reported. They noticed that a trillionth of a second after the laser strikes, plasma flowed from regions of high density to those of lower density. This event caused plasma to build up at the interface between high and low density areas, generating a sound wave.

The sound was of a frequency of more than a trillion hertz, which is six million times higher than what can be heard by any mammal.

"One of the few locations in nature where we believe this effect would occur is at the surface of stars. When they are accumulating new material stars could generate sound in a very similar manner to that which we observed in the laboratory - so the stars might be singing - but, since sound cannot propagate through the vacuum of space, no-one can hear them," said John Pasley, of the York Plasma Institute in the Department of Physics at York.

The technique used to observe this sound wave works similarly to a police speeding camera, allowing the researchers to analyze how the fluid moved when struck by the laser on a timescale of less than a trillionth of a second.

"It was initially hard to determine the origin of the acoustic signals, but our model produced results that compared [favorably] with the wavelength shifts observed in the experiment. This showed that we had discovered a new way of generating sound from fluid flows. Similar situations could occur in plasma flowing around stars," said Alex Robinson from the Plasma Physics Group at STFC's Central Laser Facility.""

http://www.hngn.com/articles/79515/20150323/stars-sing-a-song-but-its-too-high-for-even-bats-to-hear.htm

Advanced Photographic Tools Unmanned Autonomous Underwater Robotic Vehicles Uncover Deep-sea Ecosystem Diversity at ‘Landscape’ Scales

""Scientists at the National Oceanography Centre (NOC) have used advanced photographic tools in an unmanned Autonomous Underwater Vehicle (AUV) to make major advancements in estimating deep-sea ecosystem diversity at 'landscape' scales.

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By using a camera on the Autosub6000 AUV to take a continuous stream of high resolution photographs of life on the sea floor, this new method revealed a tenfold increase in the precision of deep sea ecosystem diversity estimates relative to the use of scientific trawling. Autosub6000 was developed by the NOC as part of an ongoing project. This research showed that Anemones were the most abundant animal on the sea floor, information that has been previously missed from trawling because they became damaged in the nets and rendered unrecognisable.

Dr Kirsty Morris, the lead author of this research, published in Limnology and Oceanography: Methods, said "This is an important step towards the automated imaging of the deep sea, which is essential for understanding the complexity of seafloor biodiversity and its future management"

Once the images were taken they were analysed to identify the types of creatures seen, calculate their relative abundances and estimate their size relative to the image pixels. This allows for an overall estimate of the biomass to be calculated and compared with later/earlier images in order to monitor how these ecosystems change over time.

As climate change and potential exploitive pressure of seafloor resources impact the ocean, it is increasingly important to better document deep sea marine biodiversity and ecosystems. Currently trawling is one of the most common methods of assessing what creatures live in these habitats; however trawling has drawbacks in terms of poor accuracy and a bias in sampling seafloor biota. The new method, developed at the NOC, will substantially improve the accuracy and efficiency of sea floor surveying.

This method was developed and tested as part of the NERC funded AESA (Autonomous Ecological Surveying of the Abyss) project. It is currently being used to map the proposed marine conservation zone, know as Haig-Fras, as well as to estimate the seafloor carbon dynamics within the vicinity. This project will involve evaluating the role of habitat and sediment type, as well as discovering which animals live there.

Dr Henry Ruhl, co-ordinator of the AESA project, said "We are creating photographic maps of animals on the seafloor, which can scale up to the size of cities. This allows us to understand links between ecology, ecological functioning, and human impact in a way that was not previously feasible.""

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Hardware Entering Key Test Phase for the James Webb Space Telescope Flagship Program Project

James Webb Space Telescope 

hardware entering key test phase

January 7, 2015 by Chris Bergin

""An array of high tech instruments are being put through their paces ahead of becoming part of the James Webb Space Telescope (JWST). The successor to the Hubble Space Telescope – JWST engineers are currently testing hardware to ensure it will be able to function properly 1.5 million miles from Earth. The spacecraft is preparing for a launch late in 2018.

JWST:

The JWST is one of NASA’s flagship programs and will be tasked with investigating the birth and evolution of galaxies, and the formation of stars and planets.

Set for launch in October, 2018 via an Ariane 5 launch vehicle, JWST will be the scientific successor to the Hubble and Spitzer Space Telescopes.

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The hugely expensive project came close to cancellation in 2011, after the program suffered with schedule slips and budget overruns. With $3 billion already spent on the JWST program, along with 75 percent of its hardware already in production, the telescope was given a stay of execution, albeit with costs capped at $8 billion.

It was originally forecast to cost just $1.6 billion.

The project has NASA, ESA and the CSA as the lead partners, but includes a collaboration of about 17 countries in total.

To be located 1.5 million kilometers from Earth at the Earth-Sun Lagrangian point L2, JWST’s 6.5-meter diameter primary mirror – a gold coated beryllium reflector – and four specialized instruments ensure the spacecraft will provide unprecedented resolution and sensitivity from long-wavelength visible to the mid-infrared.

Unlike Hubble’s single monolithic primary mirror, JWST’s primary mirror is made up of 18 individual, adjustable segments that will be aligned in space.

The spacecraft’s array of instrumentation is currently being tested to ensure it can survive the extremes of space, with the most recent test involving the Near Infrared Camera (NIRCam) instrument, which is the primary imager covering the infrared wavelength range 0.6 to 5 microns.

NIRCam will detect light from the earliest stars and galaxies in the process of formation, the population of stars in nearby galaxies, as well as young stars in the Milky Way and Kuiper Belt objects.

NIRCam is equipped with coronagraphs, instruments that allow astronomers to take pictures of very faint objects around a central bright object, like stellar systems. Its coronagraphs work by blocking a brighter object’s light, making it possible to view the dimmer object nearby.

With the coronagraphs, astronomers hope to determine the characteristics of planets orbiting nearby stars, which is of great interest over recent years,thanks to the discoveries made by NASA’s Kepler spacecraft. ""

Find out more @ nasaspaceflight.com