All Entries Tagged With: "Australian Science"
Why was Australia lit up like Christmas tree?
The apparent abundance of lights in this satellite image of Australia’s desolate outback, is easily explained – the image is made up of multiple images taken over many days and combined one on top of the other. So occasional fires or lightning bursts here and there have apparently joined up to produce large light shows in remote areas.
TWO WEEKS AGO, NASA’S Earth Observatory web site published a new map of the Earth at night, built by Earth Observatory designers together with colleagues at the US National Geophysical Data Center. That map—made possible by a new NASA and the National Oceanic and Atmospheric Administration (NOAA) satellite—showed the footprint of human civilisation on the planet, as revealed by the lights we use to brighten the darkness.
But it turns out the map showed something more. Astute readers noticed lights in areas that were thought to be uninhabited. Many of those readers pointed to Western Australia and asked: How can there be so much light there?
The image above shows the night-lights of Australia as observed by the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite in April and October 2012. It is made up of multiple images that show both manmade light sources and the light of fires. The images were acquired over nine days in April 2012 and thirteen days in October 2012.
A closer view of Western Australia at night.
The extent of the lighting is a results of combining multiple images. Fires and other lights that were detected on one day were integrated into the composite, multi-day picture despite being temporary phenomena. Because different lands burned at different times that the satellite passed over, the cumulative result is the appearance of a massive blaze. But while the cities are fixed, the fires were temporary, moveable features.
Not every light in the night view matches up with a fire—partly because the fire map does not include fires from April and partly because not every fire leaves a scar that is detectable from space. Even simple cloud cover could prevent burn scars from being observed.
Aside from the fires, some of the night lights appearing in uninhabited areas can be attributed to natural gas flares, lightning, oil drilling or mining operations, and fishing boats—all of which can show up as points of light.
Adapted from information issued by NASA Earth Observatory. NASA Earth Observatory images by Robert Simmon, using Suomi NPP VIIRS data provided by Chris Elvidge (NOAA National Geophysical Data Center); MODIS Active Fire & Burned Area Products; and urban data from the University of Wisconsin-Madison Center for Sustainability and the Global Environment. Suomi NPP is the result of a partnership between NASA, NOAA, and the Department of Defense. Caption by Michael Carlowicz.
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SKA telescope to be split
Artist's impression of SKA dishes.
IT HAS JUST BEEN ANNOUNCED that the international Square Kilometre Array (SKA) radio telescope system, will be hosted jointly by the two bidding regions – Australia-New Zealand and South Africa. The SKA will comprise around 3,000 antennae of different types to cover low-, mid- and high-frequency ranges.
Following is the text of the announcement made by the SKA organisation:
The Members of the SKA Organisation today agreed on a dual site solution for the Square Kilometre Array telescope, a crucial step towards building the world’s largest and most sensitive radio telescope.
The ASKAP (Australian Square Kilometre Array Pathfinder) and MeerKAT precursor dishes will be incorporated into Phase I of the SKA which will deliver more science and will maximise on investments already made by both Australia and South Africa.
The majority of the members were in favour of a dual-site implementation model for SKA. The members noted the report from the SKA Site Advisory Committee that both sites were well suited to hosting the SKA and that the report provided justification for the relative advantages and disadvantages of both locations, but that they identified Southern Africa as the preferred site. The members also received advice from the working group set up to look at dual site options.
The majority of SKA dishes in Phase 1 will be built in South Africa, combined with MeerKAT. Further SKA dishes will be added to the ASKAP array in Australia. All the dishes and the mid frequency aperture arrays for Phase II of the SKA will be built in Southern Africa while the low frequency aperture array antennas for Phase I and II will be built in Australia.
“This hugely important step for the project allows us to progress the design and prepare for the construction phase of the telescope. The SKA will transform our view of the Universe; with it we will see back to the moments after the Big Bang and discover previously unexplored parts of the cosmos,” says Dr Michiel van Haarlem, Interim Director General of the SKA Organisation.
The SKA will enable astronomers to glimpse the formation and evolution of the very first stars and galaxies after the Big Bang, investigate the nature of gravity, and possibly even discover life beyond Earth.
“Today we are a stage closer to achieving our goal of building the SKA. This position was reached after very careful consideration of information gathered from extensive investigations at both candidate sites,” said Professor John Womersley, Chair of the SKA Board of Directors. “I would like to thank all those involved in the site selection process for the tremendous work they have put in to enable us to reach this point.”
Factors taken into account during the site selection process included levels of radio frequency interference, the long term sustainability of a radio quiet zone, the physical characteristics of the site, long distance data network connectivity, the operating and infrastructure costs as well as the political and working environment.
The agreement was reached by the Members of the SKA Organisation who did not bid to host the SKA (Canada, China, Italy, the Netherlands and the United Kingdom). The Office of the SKA Organisation will now lead a detailed definition period to clarify the implementation.
Scientists and engineers from around the world, together with industry partners, are participating in the SKA project which is driving technology development in antennas, data transport, software and computing, and power. The influence of the SKA project extends beyond radio astronomy. The design, construction and operation of the SKA have the potential to impact skills development, employment and economic growth in science, engineering and associated industries, not only in the host countries but in all partner countries.
About the SKA
The Square Kilometre Array will be the world’s largest and most sensitive radio telescope. The total collecting area will be approximately one square kilometre giving 50 times the sensitivity, and 10,000 times the survey speed, of the best current-day telescopes.
Thousands of receptors will extend to distances of 3,000 km from the centre of the telescope, the SKA will address fundamental unanswered questions about our Universe including how the first stars and galaxies formed after the big bang, how dark energy is accelerating the expansion of the Universe, the role of magnetism in the cosmos, the nature of gravity, and the search for life beyond Earth.
The target construction cost is €1,500 million and construction of Phase 1 of the SKA is scheduled to start in 2019. The SKA Organisation, with its headquarters in Manchester UK, was established in December 2011 as a not-for-profit company in order to formalise relationships between the international partners and centralise the leadership of the project.
Members of the SKA Organisation:
Australia: Department of Innovation, Industry, Science and Research
Canada: National Research Council
China: National Astronomical Observatories, Chinese Academy of Sciences
Italy: National Institute for Astrophysics
New Zealand: Ministry of Economic Development
Republic of South Africa: National Research Foundation
The Netherlands: Netherlands Organisation for Scientific Research
United Kingdom: Science and Technology Facilities Council
Associate member:
India: National Centre for Radio Astrophysics
Images courtesy SPDO / Swinburne Astronomy Productions.
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Australia from Space – Outback fires
NASA's Aqua satellite took this image showing dozens of fires scattered across the Kimberley region of Western Australia in early May. The red colours are markers of the locations of the fires, not actually visible flames.
WHEN THIS IMAGE WAS CAPTURED on May 2, 2012, dozens of fires—most likely management fires started by government authorities—were burning in the Kimberley region of Western Australia.
Fire season in this part of Australia usually begins in May and ends in November. Once started, fires can be difficult to control. Much of the vegetation is fire prone, and the terrain is hard to access with the big machines (such as bulldozers) used to extinguish fires.
But since May is only the beginning of the dry season, vegetation is still relatively moist, and fires are relatively easy to contain. Authorities take advantage of this by starting management fires that are designed to remove vegetation that could fuel large wildfires later in the season.
Because officials are concerned that wildfires are taking a toll on the local tourism industry, they have intensified their efforts to prevent damaging wildfires. As part of this effort, they have begun setting patches of oval-shaped fires rather than burning linear fire breaks as they did in the past, according to an article published by Australian Geographic. The new approach has reduced the overall fire size, and posed fewer threats to animals and plants in the Kimberley region.
The image above was acquired at 12:20pm local time on May 2 by the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA’s Aqua satellite. Fires continued to burn nearby over the following days, although clouds moved in around May 6, 2012. The LANCE MODIS Rapid Response system provides twice daily images of northwestern Australia.
NASA image by Jeff Schmaltz, LANCE MODIS Rapid Response. Text adapted from information issued by caption by Adam Voiland and Michon Scott, NASA Earth Observatory.
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Australia from Space: Menindee Lakes
Menindee Lakes, as photographed by astronauts aboard the International Space Station.
IN THE FAR WEST of New South Wales, Australia, near the town of Menindee, a system of ephemeral, freshwater lakes are fed by the Darling River when it floods. Lake Tandou is the longest, at 18.6 kilometres from north to south. The Darling River itself was flowing in December 2011 when this image was made.
The Darling River flows southwest in tortuous fashion across the flat landscapes of this part of Australia. It has created several inland deltas in its course to the sea, with characteristic diverging channel patterns marked by younger sediments that appear greyer than the ancient red soils and rocks surrounding them.
One inland delta appears at image right, where minor channels wind across the countryside. The apex of another inland delta appears at image lower left.
Some of the Menindee Lakes have been incorporated into an artificially regulated overflow system providing for flood control, water storage for domestic use and livestock, and downstream irrigation.
The floor of Lake Tandou is used as prime agricultural land, as evidenced by its patchwork of irrigated fields that are protected from flooding. The lakes also serve as important wetlands supporting a rich diversity of birds.
Text adapted from information issued by M. Justin Wilkinson, Jacobs/ESCG at NASA-JSC. Astronaut photograph provided by the ISS Crew Earth Observations experiment and Image Science & Analysis Laboratory, Johnson Space Centre.
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Earth from Space – Cocos (Keeling) Islands
NASA satellite image of the South Keeling Islands, part of the Cocos (Keeling) Islands archipelago in the Indian Ocean between Australia and Sri Lanka.
THE COCOS (KEELING) ISLANDS lie in the eastern Indian Ocean, about 2,900 kilometres northwest of Perth, Western Australia. It is about halfway between Australia and Sri Lanka.
Comprised of coral atolls and islands, the archipelago includes North Keeling Island and the South Keeling Islands. Total human population is about 600.
The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite captured this natural-colour image of South Keeling Islands on July 31, 2009.
Coral atolls—which are largely composed of huge colonies of tiny animals such as cnidaria—form around islands. After the islands sink, the coral remains, generally forming complete or partial rings. Only some parts of South Keeling Islands still stand above the water surface. In the north, the ocean overtops the coral.
Along the southern rim of this coral atoll, the shallow water appears aquamarine. Water darkens to navy blue as it deepens toward the central lagoon. Above the water line, coconut palms and other plants form a thick carpet of vegetation.
In 2005, the Australian government issued a report on the Cocos (Keeling) Islands, summarising field research conducted between 1997 and 2005. It found that hard corals, which play a primary role in reef building, were not the only corals at South Keeling Islands. Soft corals were also thriving at study sites throughout the reef. Although coral and rock predominated, the researchers also found varying amounts of silt, sand, rubble, sponges, and seaweed
Some of the coral had recently died, and coral predators appeared in high densities at some sites. But overall, the report noted, “the coral reef community at Cocos (Keeling) Islands is very healthy and in a stable period, with little impact from anthropogenic activities.”
The Cocos Islands are served by regular Virgin Australia flights, which land on and depart from the single 2,438-metre-long runway shown in the enlargement below:
Close up satellite image of the runway on the Cocos (Keeling) Islands.
For a full-size version of the main image, click here (3MB)
NASA Earth Observatory image created by Jesse Allen and Robert Simmon, using EO-1 ALI data provided courtesy of the NASA EO-1 team. Text adapted from information issued by Michon Scott.
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Giant star-jet astounds astronomers
Sanduleak's star and the jet of matter shooting out from it at more than 5 million kilometres per hour. The jet is now 400 million million kilometres long.
- Star shooting out jet of material 400 million million km long
- Thought to occur due to interaction between two stars
- Located in the Large Magellanic Cloud galaxy
ASTRONOMERS HAVE FOUND a star spitting matter into a “jet” that stretches for more than 400 million million kilometres across space.
That’s about ten times the distance between the Sun and its nearest neighbouring star (proxima Centauri).
It’s the biggest jet known from a star, and “challenges our current understanding,” said Dr Francesco Di Mille (Australian Astronomical Observatory and the University of Sydney), a member of the team that made the finding.
Theoretical models don’t deal with it, he said, “simply because nobody would ever have bet that such a giant stellar jet could exist”.
In a galaxy not so far away
The star making the jet is called Sanduleak’s star, having been discovered by astronomer Nicholas Sanduleak in 1977.
Sanduleak noted that the star varied in brightness, but didn’t see the jet.
That’s not surprising. The star is shrouded by dust, and it’s not even in our Galaxy—it’s in a small neighbouring galaxy called the Large Magellanic Cloud, about 160 thousand light-years away.
Finding the jet fell to Dr Di Mille’s team, led by Italian astronomer Rodolfo Angeloni (Pontificia Universidad Católica de Chile), which turned the 6.5-m Magellan Telescopes in Chile on the star.
Observations were made with the Magellan Telescopes in Chile.
Outburst 10,000 years old
Dust surrounding the star makes it hard to tell exactly what’s going on, but it seems that actually two stars are involved: a red giant and a white dwarf, tangoing closely.
The red giant’s hot “breath”—transferred matter—curls into a belt around the white dwarf’s belly. From time to time a jet shoots up and down from this disc of material, along the star’s axis of rotation.
An artist's impression of a system like Sanduleak's star—a red giant star transferring matter onto a white dwarf star.
Astronomers have worked out that the current outburst has been going on for about ten thousand years, and that the material in the jet is travelling at more than 5 million kilometres per hour (1,500 km per second).
“Because we know the distance to this star we’ll be able to make good estimates of most of the jet’s properties,” Dr Di Mille said.
“It will be the best test-case for understanding jets from stars.”
The researchers have published their finding in The Astrophysical Journal Letters.
Adapted from information issued by AAO. Magellan Telescopes image courtesy Francisco Figueroa. Sanduleak’s star image courtesy R. Angeloni et al. Artist’s impression courtesy Dana Berry (STScI).
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Australia from Space: Part 5
IT’S DIFFICULT TO GET A TRUE PICTURE of the scale of Australia’s Red Centre from the ground, but satellite images help us to comprehend the breadth and beauty of the region. These remarkable images were taken by the Proba, Envisat and Landsat satellites, and show two of Australia’s most famous landmarks—Uluru and Lake Eyre.
The rock formation Uluru, also known as Ayers Rock, as seen by the European Proba satellite. Uluru is the world's largest monolith, and a sacred site to Australia's indigenous peoples. It is 3.6 km long and two km wide. The walk around it covers 9.4 km.
This black and white Proba image gives us a closer view of Uluru, and shows the layers of rock titled towards the vertical.
This Envisat image highlights the Lake Eyre Basin, one of the world’s largest internally draining systems, in the heart of Australia. White cloud streaks stand in contrast to the Red Centre’s vast amounts of crimson soil and sparse greenery. The basin covers about 1.2 million sq km (about the size of France, Germany and Italy combined), including large portions of South Australia (bottom), the Northern Territory (upper left) and Queensland (upper right) and a part of western New South Wales (bottom right). This image was acquired by the European Envisat satellite’s Medium Resolution Imaging Spectrometer on 3 July 2010 at a resolution of 300 metre.
This Landsat satellite image shows a portion of Lake Eyre (lower-left corner) and the north-south sand dunes of the Simpson and Tirari deserts in the remote outback of South Australia. The Thematic Mapper on Landsat 5 acquired this image on 31 May 2011.
Earlier Australia from Space pictorials:
Adapted from information issued by ESA.
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Australia’s newest telescopes – bird’s eye view
The Australian Square Kilometre Array Pathfinder (artist's impression) is under construction in a remote part of Western Australia.
A NEW WEB FEATURE makes it possible to take a ‘bird’s eye view’ over the Murchison Radio-astronomy Observatory (MRO) and see the construction progress of CSIRO’s ASKAP radio telescope.
ASKAP Live is an interactive map of the 36 antennae that will make up the Australian Square Kilometre Array Pathfinder (ASKAP). In addition to showing the location of each antenna, ASKAP Live gives pictures and status reports on the construction of each antenna.
Colour coding provides, at a glance, the construction status of each antenna: antennae indicated by green icons have already been completed, those currently being constructed are in blue, and the six antennae that will make up the Boolardy Engineering Test Array, or BETA, are marked with yellow or purple icons.
A screenshot from the ASKAP Live web site.
All 36 ASKAP antennae are being constructed at the MRO by their manufacturer, the 54th Research Institute of China Electronics Technology Group Corporation (known as CETC54), with the assistance of CSIRO’s ASKAP team and local contractors.
The antennae are first built and tested in China by CETC54, with the antenna sections then disassembled and shipped to Australia. The antennae are then reassembled on site at the MRO, approximately 315 kilometres north east of Geraldton in the Mid West region of Western Australia.
Once built, ASKAP will operate as part of CSIRO’s radio astronomy facility for use by Australian and international scientists.
As well as being a world-leading telescope in its own right, ASKAP will be an important test-bed for the Square Kilometre Array (SKA), a future international radio telescope that will be the world’s largest and most sensitive.
Take a look at ASKAP Live.
You can also view the ASKAP Webcam.
Adapted from information issued by CSIRO.
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Australia from Space: Part 4
MORE WONDERFUL IMAGES of Australia’s coastline, courtesy of the European Envisat Earth-monitoring satellite. Envisat was launched in March 2002 and at 8.5-tonnes is one of the largest satellites ever put into orbit. It circles the Earth every 101 minutes from north to south.
An Envisat MERIS image of the Great Barrier Reef centred on Cape York Peninsula. Taken on 19 August 2004, this MERIS Full Resolution mode images has a spatial resolution of 300 metres.
This Envisat image features the southern part of the Great Barrier Reef off Australia’s Queensland coast. It is the world’s most protected marine area, one of its natural wonders and a World Heritage site. Spanning more than 2,000 km and covering an area of some 350,000 sq km, it is the largest living structure on Earth and the only one visible from space. This image was acquired by Envisat’s Medium Resolution Imaging Spectrometer (MERIS) on 8 November 2010 at a resolution of 300 metres
Another view of the Great Barrier Reef. Australian researchers have discovered that Envisat's Medium Resolution Imaging Spectrometer (MERIS) sensor can detect coral bleaching down to 10 metres depth. This means Envisat could potentially map coral bleaching on a global scale. MERIS acquired this image on 18 May 2008, working in Full Resolution mode to yield a spatial resolution of 300 metres.
Sea and coral atolls off the West Australian coast, as seen by Envisat's MERIS ocean colour sensor.
Earlier Australia from Space pictorials:
Adapted from information issued by ESA.
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Australian dish charts where stars are born
The Large Magellanic Cloud (LMC) is the nearest sizeable galaxy to our Milky Way, and is therefore a popular target for astronomers studying the evolution of stars.
ASTRONOMERS HAVE MAPPED in detail the star-forming regions of the nearest star-forming galaxy to our own, a step toward understanding the conditions surrounding star creation.
The researchers, led by University of Illinois astronomy professor Tony Wong—and including Associate Professor Sarah Maddison and PhD student Annie Hughes, both of the Swinburne University of Technology in Melbourne, Australia—have published their findings in the December issue of the Astrophysical Journal Supplement Series.
The Large Magellanic Cloud (LMC) is a popular galaxy among astronomers both for its nearness to our Milky Way and for the spectacular view it provides, a big-picture vista impossible to capture of our own galaxy.
“If you imagine a galaxy being a disc, the LMC is tilted almost face-on so we can look down on it, which gives us a very clear view of what’s going on inside,” Wong said.
CSIRO's 22-metre-diameter Mopra radio telescope, located near Coonabarabran in NSW.
As the LMC is in the far southern sky, it is an ideal target for Australian telescopes. And indeed, the team used the CSIRO’s 22-metre-diameter radio telescope at Mopra, near Coonabarabran in north-central New South Wales.
Where are stars born?
Although astronomers have a working theory of how individual stars form, they know very little about what triggers the process or the conditions in space that are optimal for star birth.
Wong’s team focused on areas called molecular clouds, which are dense patches of gas—primarily molecular hydrogen—where stars are born. By studying these clouds and their relationship to new stars in the galaxy, the team hoped to learn more about how gas clouds turn into stars.
Using the Mopra dish, the astronomers mapped more than 100 molecular clouds in the LMC and estimated their sizes and masses, identifying regions with ample material for making stars. This seemingly simple task engendered a surprising find.
Conventional wisdom states that most of the molecular gas in a galaxy is apportioned to a few large clouds. However, Wong’s team found many more low-mass clouds than they expected—so many, in fact, that a majority of the dense gas may be sprinkled across the galaxy in these small molecular clouds, rather than clumped together in a few large blobs.
False-colour image of the Large Magellanic Cloud galaxy combining maps of neutral atomic hydrogen gas (red), hydrogen energised by nearby young stars (blue), and new data from Wong’s team which roughly show the locations of dense clouds of molecular hydrogen (green). It's thought that stars form within molecular hydrogen clouds.
Star formation widespread in the LMC galaxy
The large numbers of these relatively low-mass clouds means that star-forming conditions in the LMC may be relatively widespread and easy to achieve.
To better understand the connection between molecular clouds and star formation, the team compared their molecular cloud maps to maps of infrared radiation, which reveal where young stars are heating cosmic dust.
“It turns out that there’s actually very nice correspondence between these young massive stars and molecular clouds,” Wong said.
“We can say with great confidence that these clouds are where the stars form, but we are still trying to figure out why they have the properties they do,” he added.
Adapted from information issued by University of Illinois at Urbana-Champaign. Mopra photo courtesy CSIRO. MAGMA image of LMC courtesy Tony Wong, University of Illinois.
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