This Is How The World’s Largest Radio Telescope Is Divvying Up Design Work

The world’s largest radio telescope will act very much like a jigsaw; every piece of it must be precisely engineered to “fit” and to work with all the other elements. This week, the organizers of the Square Kilometer Array released which teams will be responsible for the individual “work packages” for this massive telescope, which will be in both South Africa and Australia.

“Each element of the SKA is critical to the overall success of the project, and we certainly look forward to seeing the fruits of each consortium’s hard work shape up over the coming years”, stated John Womersley, chair of the SKA board.

“Now this multi-disciplinary team of experts has three full years to come up with the best technological solutions for the final design of the telescope, so we can start tendering for construction of the first phase in 2017 as planned.”

Key science goals for SKA include the evolution of galaxies, the nature of mysterious dark energy, examining the nature of gravity and magnetism, looking at how black holes and stars are created, and even searching for extraterrestrial signals. We’ll illustrate some of those key science concepts while talking about the teams below.

This illustration shows a messy, chaotic galaxy undergoing bursts of star formation. This star formation is intense; it was known that it affects its host galaxy, but this new research shows it has an even greater effect than first thought. The winds created by these star formation processes stream out of the galaxy, ionising gas at distances of up to 650 000 light-years from the galactic centre. Credit: ESA, NASA, L. Calçada
This illustration shows a messy, chaotic galaxy undergoing bursts of star formation. This star formation is intense; it was known that it affects its host galaxy, but this new research shows it has an even greater effect than first thought. The winds created by these star formation processes stream out of the galaxy, ionising gas at distances of up to 650 000 light-years from the galactic centre. Credit: ESA, NASA, L. Calçada

The numbers themselves on the teams are staggering: more than 350 scientists and engineers, representing 18 countries and almost 100 institutions. There are 10 main work packages that these people are responsible for. Here they are, along with SKA’s descriptions of each element:

Dish: “The “Dish” element includes all activities necessary to prepare for the procurement of the SKA dishes, including local monitoring & control of the individual dish in pointing and other functionality, their feeds, necessary electronics and local infrastructure.” (Led by Mark McKinnon of  Australia’s Commonwealth Scientific and Industrial Research Organisation, or CSIRO.)

– Low Frequency Aperture Array: “The set of antennas, on board amplifiers and local processing required for the Aperture Array telescope of the SKA.” (Led by Jan Geralt Bij de Vaate of ASTRON, or the Netherlands Institute for Radio Astronomy).

– Mid Frequency Aperture Array: “Includes the activities necessary for the development of a set of antennas, on board amplifiers and local processing required for the Aperture Array telescope of the SKA.” (Led by de Vaate.)

Artist’s schematic impression of the distortion of spacetime by a supermassive black hole at the centre of a galaxy. The black hole will swallow dark matter at a rate which depends on its mass and on the amount of dark matter around it. Image: Felipe Esquivel Reed.
Artist’s schematic impression of the distortion of spacetime by a supermassive black hole at the centre of a galaxy. The black hole will swallow dark matter at a rate which depends on its mass and on the amount of dark matter around it. Image: Felipe Esquivel Reed.

– Telescope Manager: “Will be responsible for the monitoring of the entire telescope, the engineering and operational status of its component parts.” (Led by Yashwant Gupta of the NCRA or National Centre for Radio Astrophysics in India.)

– Science Data Processor: “Will focus on the design of the computing hardware platforms, software, and algorithms needed to process science data from the correlator or non-imaging processor into science data products.” (Led by Paul Alexander of the University of Cambridge, United Kingdom.)

– Central Signal Processor: “It converts digitised astronomical signals detected by SKA receivers (antennas & dipole (“rabbit-ear”) arrays) into the vital information needed by the Science Data Processor to make detailed images of deep space astronomical phenomena that the SKA is observing.” (David Loop of the NRC, National Research Council of Canada.)

The supernova that produced the Crab Nebula was detected by naked-eye observers around the world in 1054 A.D. This composite image uses data from NASA’s Great Observatories, Chandra, Hubble, and Spitzer, to show that a superdense neutron star is energizing the expanding Nebula by spewing out magnetic fields and a blizzard of extremely high-energy particles. The Chandra X-ray image is shown in light blue, the Hubble Space Telescope optical images are in green and dark blue, and the Spitzer Space Telescope’s infrared image is in red. The size of the X-ray image is smaller than the others because ultrahigh-energy X-ray emitting electrons radiate away their energy more quickly than the lower-energy electrons emitting optical and infrared light. The neutron star is the bright white dot in the center of the image.
The supernova that produced the Crab Nebula was detected by naked-eye observers around the world in 1054 A.D. This composite image uses data from NASA’s Great Observatories, Chandra, Hubble, and Spitzer, to show that a superdense neutron star is energizing the expanding Nebula by spewing out magnetic fields and a blizzard of extremely high-energy particles. The Chandra X-ray image is shown in light blue, the Hubble Space Telescope optical images are in green and dark blue, and the Spitzer Space Telescope’s infrared image is in red. The size of the X-ray image is smaller than the others because ultrahigh-energy X-ray emitting electrons radiate away their energy more quickly than the lower-energy electrons emitting optical and infrared light. The neutron star is the bright white dot in the center of the image.

 Signal and Data Transport: “The Signal and Data Transport (SADT) consortium is responsible for the design of three data transport networks.” (Led by Richard Schilizzi of the University of Manchester, United Kingdom.)

– Assembly, Integration & Verification: “Includes the planning for all activities at the remote sites that are necessary to incorporate the elements of the SKA into existing infrastructures, whether these be precursors or new components of the SKA.” (Led by Richard Lord of SKA South Africa.)

– Infrastructure: “Requires two consortia, each managing their respective local sites in Australia and Africa … This includes all work undertaken to deploy and be able to operate the SKA in both countries such as roads, buildings, power generation and distribution, reticulation, vehicles, cranes and specialist equipment needed for maintenance which are not included in the supply of the other elements.” (Led by Michelle Storey of CSIRO.)

Wideband Single Pixel Feeds: “Includes the activities necessary to develop a broadband spectrum single pixel feed for the SKA.” (Led by John Conway of Chalmers University, Sweden.)

Stacking Galactic Signals Reveals A Clearer Universe

Very similar to stacking astronomy images to achieve a better picture, researchers from the International Centre for Radio Astronomy Research (ICRAR) are employing new methods which will give us a clearer look at the history of the Universe. Through data taken with the next generation of radio telescopes like the Square Kilometer Array (SKA), scientists like Jacinta Delhaize can “stack” galactic signals en masse to study one of their most important properties… how much hydrogen gas is present.

Probing the cosmos with a telescope is virtually using a time machine. Astronomers are able to look back at the Universe as it appeared billions of years ago. By comparing the present with the past, they are able to chart its history. We can see how things have changed over the ages and speculate about the origin and future of the vastness of space and all its many wonders.

“Distant, younger, galaxies look very different to nearby galaxies, which means that they’ve changed, or evolved, over time,” said Delhaize. “The challenge is to try and figure out what physical properties within the galaxy have changed, and how and why this has happened.”

According to Delhaize a vital clue to solving the riddle lay in hydrogen gas. By understanding how much of it that galaxies contained will help us map their history.

“Hydrogen is the building block of the Universe, it’s what stars form from and what keeps a galaxy ‘alive’,” said Delhaize.

“Galaxies in the past formed stars at a much faster rate than galaxies now. We think that past galaxies had more hydrogen, and that might be why their star formation rate is higher.”

Jacinta Delhaize with CSIRO's Parkes Radio Telescope during one of her data collecting trips. Credit: Anita Redfern Photography.
Jacinta Delhaize with CSIRO’s Parkes Radio Telescope during one of her data collecting trips. Credit: Anita Redfern Photography.
When it comes to distant galaxies, they don’t give up their information easily. Even so, it was a task that Delhaize and her supervisors were determined to observe. The faint radio signals of hydrogen gas were nearly impossible to detect, but the new stacking method allowed the team to collect enough data for her research. By combining the weak signals of thousands of galaxies, Delhaize then “stacked” them to create a stronger, averaged signal,

“What we are trying to achieve with stacking is sort of like detecting a faint whisper in a room full of people shouting,” said Delhaize. “When you combine together thousands of whispers, you get a shout that you can hear above a noisy room, just like combining the radio light from thousands of galaxies to detect them above the background.”

However, it wasn’t a slow process. The researchers engaged CSIRO’s Parkes Radio Telescope for 87 hours and surveyed a large region of galactic landscape. Their work collected signals from hydrogen over a vast amount of space and stretched back over two billion years in time.

“The Parkes telescope views a big section of the sky at once, so it was quick to survey the large field we chose for our study,” said ICRAR Deputy Director and Jacinta’s supervisor, Professor Lister Staveley-Smith.

Stacking up a clearer picture of the Universe from ICRAR on Vimeo.

As Delhaize explains, observing such a massive volume of space means more accurate calculations of the average amount of hydrogen gas present in particular galaxies at a certain distance from Earth. These readings correspond to a given period in the history of the Universe. With this data, simulations can be created to depict the Universe’s evolution and give us a better understanding of how galaxies formed and evolved with time. What’s even more spectacular is that next generation telescopes like the international Square Kilometre Array (SKA) and CSIRO’s Australian SKA Pathfinder (ASKAP) will be able to observe even larger volumes of the Universe with higher resolution.

“That makes them fast, accurate and perfect for studying the distant Universe. We can use the stacking technique to get every last piece of valuable information out of their observations,” said Delhaize. “Bring on ASKAP and the SKA!”.

Original Story Source: International Centre for Radio Astronomy Research.

Book Review: African Cosmos

In 1986, Halley’s Comet captivated a teenager living in a small South African town. Curious about what his nation does in astronomy, he scoured books at the local library and asked questions of his teachers.

It was, however, a tough time to learn about it. Under apartheid, African science was seen as “nothing of merit” until the Westerners colonized the continent two centuries ago.

This tale, told in African Cosmos: Stellar Arts, portrays part of the difficulty of reporting on African science. Turn back to  when Egyptians built the pyramids, and you can understand that astronomy goes back thousands of years on the continent. Yet, Africa is under-represented in discussions about popular astronomy. Language, scattered cultures, and distance from the Western world are all barriers.

Creating this volume must have been daunting for Christine Mullen Kreamer and her collaborators, who gathered 20 essays about African astronomy.

But you can see for yourself, as this book is available for free on iPad, and you can download it here.

Africa is a large continent with humans living anywhere from crowded cities to sparse grassland. There are at least 3,000 ethnic groups on that landmass, according to Baylor University, with many of these cultures having separate views in astronomical culture and history.

It’s hard to gather all that information into a single book, but the Smithsonian National Museum of African Art does its best.

The book opens with lengthy explanations of the Egyptian and Babylonian contributions to astronomy. The Babylonians, for example, observed the strange backwards motion of Mars when our planet “catches up” in our smaller orbit to Mars’ larger one. The Egyptians used the sky to develop a 12-month calendar to track important feasts and the time for harvests.

Retrograde motion of Mars. Image credit: NASA
Retrograde motion of Mars. Image credit: NASA

This information is readily accessible elsewhere, but the art makes it stand out. Flip the pages, and you’ll gaze at period art, maps and even astronomical tables that were on display at the museum for a 2012 exhibition.

Perhaps the most fascinating historical chapter is Cosmic Africa, which traces the development of a film of the same title. Anne Rogers and her film team did field research in seven countries to narrow down which tribes to focus on. Eventually, they settled on the Ju/’hoansi in Namibia, the Dogon in Mali and (through archaeology) the area of Nabta Playa in Egypt.

There aren’t many explanations of these peoples in the historical record, so it’s neat to see how their culture is shaped by the stars and nebulas they see. Adding to the interest, the team deliberately visited the Ju/’hoansi during a partial solar eclipse to learn how the tribe reacts to more rare astronomical events.

You’ll see a lot of tribes in this large volume, and will also get hints of the latest art and science surrounding African astronomy. The most current astronomical information is sparse, perhaps out of recognition that the information would go out of date very quickly. It might have been interesting nevertheless to include more information about the Square Kilometer Array, the world’s largest telescope, that is under development in both Africa and Australia.

For more information on the book, check out the online exhibition from the Smithsonian.

Weekly Space Hangout – Oct. 4, 2012

It was a slow week on Space news except for the massive announcement that an ancient riverbed was discovered on the surface of Mars. We took a look at this as well as the historic 55th anniversary of Sputnik, a precise measurement of the expansion of the Universe, and more!

Stories:

Panel: Amy Shira Teitel, Nicole Gugliucci, Nancy Atkinson

Host: Fraser Cain

We record the Weekly Space Hangout every Thursday at 10am PDT / 1 pm EDT. You can watch us live on Google+, Cosmoquest, or at the Universe Today YouTube channel, or listen after as part of the Astronomy Cast podcast feed (audio only).

Click here to put the next event right into your calendar.

Weekly Space Hangout for May 31, 2012

In this episode of the Weekly Space Hangout, we’re joined by special guest Robert Nemiroff from Astronomy Picture of the Day. We also talked about the return of the SpaceX Dragon capsule, a manned mission to Venus, nomadic planets and the announcement of the Square Kilometer Array. Our team included: Amy Shira Tietel, Jason Major, Alan Boyle, Nicole Gugliucci and Robert Nemiroff.

We record a new episode of the Weekly Space Hangout every Thursday at 10:00 am PT / 1:00 pm ET. You can watch us live and ask us questions, right on Google+. Circle Fraser on Google+ to see when the recording starts.

SKA, the World’s Largest Telescope Will Be Built at Two Sites

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In an anticipated great compromise, South Africa and Australia will share their sites for the Square Kilometre Array telescope, the world’s largest and most sensitive radio telescope. Both sites were competing to win the $2 billion contract for the SKA, which is hoped shed light on how the Universe began, why it is expanding and whether there is any other life beyond our planet.

“We have decided on a dual site approach,” said SKA board chairman John Womersley, following a meeting of the SKA organisation’s members. “This position was reached after very careful consideration of information gathered from extensive investigations at both candidate sites.”

An SKA press release said the majority of the members were in favor 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.

Therefore, the majority of SKA dishes in Phase 1 will be built in South Africa, combined with MeerKAT, a seven-dish prototype interferometer array built by South Africa, where 190 dishes will be added. 60 dishes will be added to the Australian Square Kilometre Array Pathfinder (ASKAP) array in Australia, as well as a large number of omni-directional dipole antennas. This will give the Australian site a wide-field survey capability, whereas South Africa will be able to look deeply into a narrow part of the sky.

Three antenna types, high frequency dishes and mid and low frequency aperture arrays, will be used by the SKA to provide continuous frequency coverage from 70 MHz to 10 GHz. Combining the signals from all the antennas will create a telescope with a collecting area equivalent to a dish with an area of about one square kilometer.

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.

“It’s a distinct possibility that we’ll discover a new type of astronomical object,” CSIRO SKA Director Brian Boyle told Universe Today in interview earlier this year. “History has shown that every time we’ve gone to a new astronomical wavelength domain, we pick up new objects.” An example of that is the discovery of pulsars in radio

At the lowest frequencies, the SKA will be looking for red-shifted hydrogen, looking at the very earliest events of our Universe. At highest frequencies will look for things like pulsars or even pre-biotic molecules in space. The array will also be very effective in looking for transient events like supernovae or gamma ray bursts.

“The placement of the array will give it a phenomenally wide field of view, between 30 and 100 square degrees,” Boyle said. “It is hoped to provide the first all-sky survey at phenomenal depths at these wavelengths, which can then be compared with other all-sky surveys done at optical wavelengths.”

One downside of splitting the frequencies between the two sites is that some of the science may suffer. One of the original science requirements of the SKA was to look at the same piece of the sky at the same time in different frequencies. Boyle said there is not much common sky between the two locations.

Another is cost for having redundant computing and networking capabilities, not cheap for the remote areas where both sites are located.

But the dual-site approach solves political issues, and the SKA press release says the arrangement “will deliver more science and will maximize on investments already made by both Australia and South Africa.”

Womersley said that in this approach “Science is the winner,” and by building on existing pilot projects in both countries, the SKA will be made even more powerful.

Additionally, technology is sure to get a boost, as the SKA project will drive technology development in antennas, data transport, software and computing, and power.

Additionally, the SKA members say 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,” said their press release.