Space and Astronomy news daily - SpaceInfo.com.au » Australian Science

Australian SKA site producing the goods

Jonathan Nally — Sat, 28 Apr 2012 06:45:19 +0000

Western Australia radioastronomy site now active
Already producing world-class research
Targets are as close as the Moon and as distant as quasars

CSIRO’s MURCHISON RADIOASTRONOMY OBSERVATORY (MRO), located in remote Western Australia, is the site proposed by Australia and New Zealand to host the high-density core of the multi-billion dollar Square Kilometre Array (SKA), and is already producing world-class research that will be described at an international conference in the UK this week.

The research uses the Murchison Widefield Array (MWA), a $50m SKA Precursor telescope located at the MRO. The MWA project is led by the International Centre for Radio Astronomy Research (ICRAR) at Curtin University.

MWA Project Director, Professor Steven Tingay, will be presenting the results at an international conference in the UK last week, and said, “The MWA is just starting to come online but is already producing world-class research, due to the extraordinarily high quality of the MRO as a location for ultra-sensitive radio telescopes.”

The MWA uses stationary antennae that look like strange metallic spiders, with no moving parts. There will be 128 groups of 16 antennae, each group known as a “tile”. The system will use huge computing power to undertake sensitive surveys of the cosmos.

Unlike the CSIRO's Parkes "dish", the Murchison Widefield Array uses strange-looking antennae space out on the ground. Seen here are three groups of 16 antennae. The system will use 128 groups.

Low interference level

Professor Tingay said that a critical requirement for the MWA is the need to operate in an environment free from radio interference generated by human activities. FM radio stations, mobile phones, cars and industrial activities are major sources of interference that drown out the whisper-faint radio signals from objects in the distant universe.

“For this reason, the MWA has been constructed at the MRO, where the level of interference is much lower than most other observatory locations around the world. An indication of the MRO site’s pristine conditions is the amount of data that is lost due to interference. At the MRO this is less than 1%, compared to close to 100% at some other observatory locations around the world,” said Tingay.

Due for completion November this year, the MWA already has a steady flow of research from it’s current configuration due to the excellent radio-quiet conditions of the MRO.

Recently, astronomers from MIT in Cambridge, Massachusetts, have used the MWA to image an area of the sky 20,000 times larger than the full Moon, covering a region of the universe that the MWA will search for the very first stars and galaxies to form, soon after the Big Bang. Researchers from the University of Washington have determined that the MWA should be capable of detecting these signals.

Aside from these papers, an avalanche of astrophysics research from the MWA is about to appear in print, ranging from studies of explosions on the Sun, to observations of signals bouncing off the Moon, to surveys looking for highly variable quasars.

The MWA is being delivered by an international consortium of 13 institutions in four countries: Australia; the USA; India; and New Zealand.

More information: Murchison Widefield Array

Adapted from information issued by ICRAR. Photography by Paul Bourke and Jonathan Knispel (supported by WASP (UWA), iVEC, ICRAR, and CSIRO).

Get SpaceInfo.com.au daily updates by RSS or email! Click the RSS Feed link at the top right-hand corner of this page, and then save the RSS Feed page to your bookmarks. Or, enter your email address (privacy assured) and we’ll send you daily updates. Or follow us on Twitter, @spaceinfo_oz

Like this story? Please share or recommend it…

Australian research into “space glass”

Jonathan Nally — Tue, 10 Apr 2012 14:01:27 +0000

Fibre optics technology could be revolutionised by Queensland University of Technology space research.

RESEARCHERS AT THE Queensland University of Technology’s (QUT) Science and Engineering Faculty are about to experiment with a special kind of glass made under weightless conditions.

Called ZBLAN, it forms improperly under gravity but could theoretically be made into a super-fibre in the absence of gravity.

Dr Martin Castillo, researcher for QUT’s micro-gravity drop tower, will work with the US Air Force to conduct first-of-its-kind researchinto ZBLAN.

ZBLAN glass made in microgravity (left) and normal gravity (right). The difference is obvious.

“This glass contains a variety of heavy metals that upon cooling create internal stresses which leads to crystallization of the material, an undesired property for glass,” said Dr Castillo. “The synthesis of this material in the absence of gravity has the ability to overcome this barrier.”

Theoretically, ZBLAN fibres would have the lowest amount of signal loss of any optical known substance. This means signals could be sent over much longer distances before needing to be boosted by power-hungry amplifiers. It would also provide increased bandwidths.

“Although this glass has been made in a few places, no one has yet figured out how to draw it into a fibre,” Dr Castillo said.

“I previously spent two years working in Japan trying to produce this glass via gas levitation and with a fibre pulling apparatus in zero gravity and was unsuccessful,” he added. “Now I think we’ve been able to formulate very new and different techniques to that used by anyone in the world.”

Initial experiments will be conducted using QUT’s drop tower. A drop tower is a vertical column, from the top of which samples can be dropped…gaining a few seconds of weightlessness—or more properly, “microgravity”—on the way down.

For the ZBLAN drops, samples will experience about 2.1 seconds of microgravity.

Left: Dr Martin Castillo at the base of QUT's micro-gravity tower. Right: Two views inside the drop tower.

This is just a foretaste though. Dr Castillo intends to conduct further experiments aboard NASA’s “Vomit Comet”, an aircraft that flies parabolic trajectories to produce a short period of microgravity.

And following that, a further experiment will be launched into space in 2013 aboard a US Air Force suborbital rocket. This will be the first QUT experiment to be lofted above the atmosphere.

“In order to stay at the leading edge of the synthesis of specialised glass, all traditional methods have to be abandoned,” Dr Castillo said.

Story by Jonathan Nally. Photos courtesy QUT / NASA.

Like this story? Please share or recommend it…

Australia from Space: Menindee Lakes

Jonathan Nally — Tue, 10 Apr 2012 14:00:45 +0000

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.

Like this story? Please share or recommend it…

New Australian satellite to launch

Jonathan Nally — Tue, 13 Mar 2012 23:58:34 +0000

Artist's impression of the Jabiru-1 satellite, due to launch in 2014 aboard an Ariane 5 rocket.

IT WAS ANNOUNCED TODAY that Australian communications company NewSat has chosen Arianespace to launch its first satellite, Jabiru-1, in 2014.

Jean-Yves Le Gall, Chairman and CEO of Arianespace, and Adrian Ballintine, founder and Chief Executive Officer of NewSat Limited (NewSat), today signed the launch services contract for the Jabiru-1 satellite at Satellite 2012 in Washington, DC.

Jabiru-1 will be boosted into geostationary transfer orbit by an Ariane 5 launch vehicle from the Guiana Space Centre, Europe’s Spaceport in French Guiana, during the fourth quarter of 2014.

Geostationary transfer orbit is a “halfway” orbit, from which a satellite’s own rocket motor then boosts it into its final orbit.

Jabiru-1 is currently being built by Lockheed Martin Commercial Space Systems using an A2100 platform. Weighing 5,900 kg at launch, it will be fitted with 50 Ka-band transponders configured in a variety of multi-spot, steerable and regional beams.

Launch of an Ariane 5 rocket

Jabiru-1′s high-powered capacity will provide flexible communication solutions to enterprise and government customers across Asia, the Middle East and eastern Africa. It offers a design life of 15 years.

Jean-Yves Le Gall, Chairman and CEO of Arianespace, said: “We are delighted to have been chosen by NewSat to launch their first satellite. Arianespace is particularly proud of this opportunity to serve a new Australian operator. For us, this latest contract provides further recognition of the outstanding quality and competitiveness of our launch services.”

The announcement comes only months after Arianespace also won the competition to launch Optus’ next satellite, Optus 10.

“Jabiru-1 is very important for us and we are very pleased to entrust Arianespace with its launch, since Arianespace sets the world standard in this market,” said Adrian Ballintine. “It is extremely important for us at NewSat to know that our first satellite will be launched by Arianespace and by Ariane 5, both synonymous with reliability and excellence.”

Arianespace is the world’s leading launch service & solutions company, providing innovation to its customers since 1980. As of 1st March 2012, Arianespace had performed 204 Ariane launches (298 payloads), 26 Soyuz launches (24 at Baikonur, Kazakhstan, and two at the Guiana Space Centre) and the first launch of Vega. It has a backlog of 23 Ariane 5, 15 Soyuz and two Vega launches, equal to more than three years of business.

More information:

Arianespace

NewSat

Adapted from information issued by Arianespace.

Like this story? Please share or recommend it…

Giant star-jet astounds astronomers

Jonathan Nally — Mon, 02 Jan 2012 13:01:59 +0000

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).

Like this story? Please share or recommend it…

Australia from Space: Part 5

Jonathan Nally — Sun, 11 Dec 2011 13:01:35 +0000

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:

Australia from Space: Part 1

Australia from Space: Part 2

Australia from Space: Part 3

Australia from Space: Part 4

Adapted from information issued by ESA.

Like this story? Please share or recommend it…

Our Sun can expect inner turmoil in old age

Jonathan Nally — Thu, 08 Dec 2011 13:01:48 +0000

Our Sun will one day become a red giant star (artist's impression), swelling up to be much bigger than it is now. Astronomers have learned that the inside and outsides of such stars are very different.

SCIENTISTS HAVE MADE a new discovery about how old stars called ‘red giants’ rotate, giving an insight into what our Sun will look like in five billion years.

The international team of scientists, including University of Sydney astronomers Professor Tim Bedding and Dr Dennis Stello, has discovered that red giants have slowed down on the outside, while their cores spin at least 10 times faster than their outer layers.

The finding, just published in the prestigious journal Nature, tells us what the Sun will look like in five billion years when it develops into a red giant.

“The heart of a star determines how it evolves, and understanding how a star rotates deep inside helps us to understand how stars like our Sun will grow old,” said Professor Tim Bedding from the University of Sydney’s School of Physics.

Using NASA’s Kepler space telescope, the team “peered” deep inside ageing red giants to make their discovery of the difference in rotation rate between the core and outer layers of the stars.

Stars and the ice skater effect

The team, led by Paul Beck from Leuven University in Belgium, analysed waves inside the stars, which appear as rhythmic variations in the surface brightness of the stars.

The effect of rotation on the frequencies of the waves is so small it took the team nearly two years of almost continuous data gathering from the Kepler satellite to make their discovery.

The cores of red giant stars have been found to spin at least 10 times faster than the outer layers.

“Red giants were once stars like our Sun, but as they age their outer layers expand to more than five times their original size and cool down significantly, so they look red,” explained Dr Dennis Stello, from the University of Sydney’s School of Physics.

“The opposite actually happens to the cores of red giants, as the core contracts and becomes extremely hot and dense,” said Dr Stello.

“We’ve just discovered that the core spins much faster than the outer layers in these old stars, which makes sense when you consider what happens to other spinning things like, say, an ice skater performing pirouettes.”

“A spinning ice skater will slow down if their arms are stretched far out, like the expanded outer layers of the red giants. The ice skater will spin faster if their arms are pulled tightly to the body, like the fast spinning contracted core of red giants.”

Star quakes reveal stellar inner secrets

The Kepler space telescope—one of NASA’s most successful space missions—is searching in the constellation Cygnus for potentially habitable planets by focussing on those similar in size to Earth. It does this by carefully and individually measuring the light coming from over 100,000 stars.

“Kepler is able to detect variations in a star’s brightnessof only a few parts in a million, so its measurements are ideally suited to detect the tiny brightness fluctuations of stars,” explained Dr Stello.

Artist's impression of the Kepler spacecraft

“We study these variations in brightness to work out what’s going on deep inside stars. It’s called asteroseismology—just as geologists use earthquakes to explore Earth’s interior, we use star quakes to explore the interiors of stars,” said Dr Stello.

Different waves reveal information on different parts of the star, and by a detailed comparison of the depth to which these waves travel inside the star the team found the rotation rate dramatically increased towards the stellar core.

In addition to helping us understand how stars age, asteroseismology will help Kepler’s mission of discovering Earth-sized planets outside our Solar System by characterising the host stars around which these planets orbit.

Adapted from information issued by the University of Sydney / ESO / L. Calcada.

Like this story? Please share or recommend it…

Australia’s newest telescopes – bird’s eye view

Jonathan Nally — Wed, 07 Dec 2011 13:01:52 +0000

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.

Like this story? Please share or recommend it…

Aussie tech helps telescopes “see in the dark”

Jonathan Nally — Wed, 07 Dec 2011 00:34:52 +0000

Australian technology will soon enable astronomers to get a clearer view of distant galaxies, by reducing the effect of the natural airglow of the sky.

AUSTRALIAN SCIENTISTS have made a major breakthrough in the drive to improve their view of the night sky and greatly increase the efficiency of ground-based telescopes.

While the night sky looks dark to the naked eye, to an astronomer working at infrared wavelengths the air actually glows brightly, drowning out the view of distant astronomical bodies.

This happens because molecules in our atmosphere emit their own infrared radiation, swamping the faint infrared light coming in from deep space.

What astronomers have needed is a way to filter out the atmospheric emission while letting through the infrared waves from stars and galaxies.

Traditional filters can only remove selected wavelengths at a time. What if a system could be devised that removes many at once?

Enter the “photonic lantern” and high-tech, wavelength-suppressing optical fibres, both the brainchild of Professor Joss Bland-Hawthorn (University of Sydney) and the team he leads.

The complex system, under development since 2004, recently underwent its first real test under the night sky—at Siding Spring Observatory in New South Wales—and passed with flying colours.

The system removed the unwanted air emissionwavelengths just as planned, while letting through the infrared from deep space. In effect, it made the sky look darker and clearer.

Professor Joss Bland-Hawthorn leads the team that has developed the photonic lantern and wavelength-suppressing optical fibres. Photo courtesy University of Sydney.

The results of the field test were published this week in the scientific journal, Nature Communications.

Looking deeper into space

The optical fibres are specially made with internal patterns that act to filter out the unwanted wavelengths, while the photonic lantern combines the output from multiple fibres. That output can then be fed into a spectrograph, a device that splits light into separate wavelengths and enables analysis to be made of the chemical nature of the stuff (stars, galaxies, nebulae) that emitted the original infrared light.

Infrared wavelengths are very important because visible wavelength light emitted from astronomical bodies when the universe was young, has by now been redshifted into the infrared by the expansion of the universe. So in order to study the universe’s past, astronomers need to see at infrared wavelengths.

The first operational device to use the new photonics was commissioned earlier this year on the Anglo-Australian Telescope. This prototype instrument, called GNOSIS, paves the way to a more powerful instrument now under development by the AAO and the University of Sydney. Called SUNESIS, it will be operational by the end of 2012.

“This will mean we’ve gone from project inception to completion within 12 months, a remarkable effort,” says Bland-Hawthorn.

And they’re also aiming to have the technology ready soon for use on other major telescopes throughout the world.

“In particular, we’re aiming at the current 8- to 10-metre class of telescopes—the largest in the world—and then the new generation of 30-metre telescopes that are currently in the design phase,” says Bland-Hawthorn.

When installed on such large telescopes, the system will enable astronomers to see five times deeper into space in the infrared part of the spectrum, which corresponds to a 100-fold increase in the volume of space covered. And that means thousands more targets for their telescopes.

And that’s not the end of it. Space-based applications also beckon, and the University of Sydney team aims to test out other uses of the photonics technology aboard a micro-satellite to be launched in 2012, as well as with high-altitude balloon flights in collaboration with NASA.

Story by Jonathan Nally. Galaxy image courtesy ESO.

Like this story? Please share or recommend it…

Australia from Space: Part 4

Jonathan Nally — Tue, 06 Dec 2011 13:01:01 +0000

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:

Australia from Space: Part 1

Australia from Space: Part 2

Australia from Space: Part 3

Adapted from information issued by ESA.

Like this story? Please share or recommend it…