Where astronomy meets data

This week iSGTW has been in Stockholm while the city prepares for its Nobel Prize Award Ceremony. We attended the IEEE eScience2011 meeting, which welcomed Brian P. Schmidt, 2011 Nobel Physics Prize winner, as a keynote speaker.

Schmidt, from the Australian National University in Canberra, talked us through how astronomy has offered insights into the history of the universe from the very earliest observations by Tycho Brahe in Sweden in the 16th Century, right through to the biggest challenges for researchers today: the search for dark energy, the tantalizing hints of faster than light particles seen at CERN and detecting life on other planets. Schmidt’s own work, which ultimately earned him his Nobel prize with Adam Riess and Saul Perlmutter, showed from observations that rather than slowing down, the expansion of the Universe is accelerating.

Brian Schmidt (far right) with Adam Riess and Saul Perlmutter, collecting the Shaw Prize in astronomy in 2006. Image courtesy Wikipedia.

Schmidt’s address to the nearly 300 delegates focused on the point where astronomy meets data. His SkyMapper project, which is currently scanning the southern sky in unprecedented detail has a peak data rate of one terabyte per day. The Australian Square Kilometer Array Pathfinder, an array of 36 radio telescope dishes being built in Australia, will generate two terabytes per second. This impressive array is still just a pathfinder project for the monumental Square Kilometer Array, which will scatter thousands of linked dishes across the desert (whether Australian or South African remains to be decided) and pose challenges in connectivity that today we do not yet have ways to solve. Schmidt predicted that astronomy will increasingly rely on IT to make sense of this sea of data, with IT specialists at the core of building new telescopes.

Comparing different catalogues of astronomical objects is particularly useful, for example, to pair up images of the same object recorded by complementary techniques. Matching them up across the databases is not always obvious, however, and the tools for this are still being developed – you need very large datasets to train the algorithms.

Social media is also increasingly playing a role in astronomy as a fast way of getting the latest news on a transient object out to the community to generate additional data. Citizen science projects such as Galaxy Zoo also fire up the public imagination and can lead to genuine discoveries – as shown by the famous example of Hanny’s ‘voorwerp’. As Schmidt told us, astronomy is extremely fertile ground for innovation in IT – big datasets, computationally literate user communities and some really big questions to solve that help to captivate the public.

Schmidt was kind enough to share some thoughts exclusively with iSGTW on the role of e-science in astronomy, the discovery that led to his Nobel prize, and what he sees as the most exciting projects in radio astronomy today.

iSGTW: Could you tell us about the role of e-science in astronomy, the challenges your field currently faces in this area and how the community is tackling these issues? For example, how is the data deluge affecting how astronomy is done?

Schmidt: Astronomy is tackling problems using better and better technology, and this inevitably leads to vast quantities of data. So this data deluge is intentional, because it allows us to better sift through the sky and do our science. Telescopes are expensive, and we want to get the most out of them that we can. In addition, astronomers are building tools that enable us to better combine information from all of the major  datasets across the world to answer questions. These allow us to squeeze every last ounce of information out of the data we collect.

iSGTW: You found out that most of the universe is made up of something we still don’t really understand. How long did it take to realize or convince yourself that this was what you had found? What was the reaction of the scientific community?

Schmidt: It took a few months to be completely convinced that the Universe was accelerating, and that we had not made some silly mistake. While there was justified skepticism in the community when we made our respective announcements, I think that because the Supernova Cosmology Project and the High-Z team made the discovery independently, that quelled some of the concerns. The other thing that contributed to a relatively broad acceptance was how having an accelerating Universe (caused by something like a Cosmological Constant) fixed several outstanding conflicts between theory and observation.

iSGTW: When you became the leader of the international team researching the accelerating universe, you were only 27-years-old and the second youngest person on the team. Do you think that your youth was an important factor in the success of the project? And since then, has the role of young people in science changed? How is the role of young scientists in Australia different from the role of young scientists in Europe or elsewhere in the world?

Schmidt: Having astronomers on the team who let a young person like me take on the running of the team, while providing a guiding hand, was a unique characteristic of our team. With youth comes time to focus all of one's energy onto a single thing - so I think this was an important ingredient in our team's efforts.

Many young scientists around the world are included as parts of larger teams and are not given the academic freedom to really pursue their own agendas. While this is a necessity of many large efforts, it does cause problems, too. Australia (and the Harvard Smithsonian Center for Astrophysics before that) provided me with the luxury of an appointment where I was free to pursue my own agenda through postdoctoral fellowships - I didn't have a boss. These are important positions to have in the mix of any country's research program.

The Yale-Columbia telescope burning in 2003, two hours after bush fires tore through the area. The Visitor's Center is in the background. Note the small dome on the center's roof has blown open. Image courtesy Ray Brown/ActewAGL.

iSGTW: Mt. Stomlo, the Australian National University’s observatory that you worked on, burnt down in 2003. The five telescopes were then consolidated into one called the Skymapper. What is it that Skymapper will do, and what do you hope to find?

Schmidt: SkyMapper is a state-of-the-art, automated, wide-field survey telescope representing a new vehicle for scientific discovery. It is sited under the dark skies of Siding Spring Observatory near Coonabarabran, central New South Wales. SkyMapper's mission is to robotically create the first comprehensive digital survey of the entire southern sky. The survey will be a massively detailed record of over a billion stars and galaxies, to a depth that is one million times fainter than the human eye can see.

The survey's data set will be made freely available to the scientific and general community via the internet. The telescope's advanced 1.35 metre modified Cassegrain optics have an f4.79 focal ratio, making the system highly efficient as a photographic instrument. At the heart of the telescope is a unique digital camera designed and constructed in house by ANU technicians. The A$2.5 million camera uses 268 million pixels to capture a region of sky 29 times larger than the full moon every minute. As well as recording the brightness and shape of objects, a series of filters enables the camera to record the spectral type of stars, giving astronomers information about their age, mass and temperature. Because SkyMapper will image each part of the sky 36 times, it will help identify changes occurring within the Universe that would otherwise pass unnoticed. This will enable astronomers to identify targets of special interest and should greatly assist in tasks such as discovering large dwarf planets like Pluto in the outer solar system, and tracking asteroids.

The volume and quality of SkyMapper data will also enable astronomers to create a comprehensive census of the stars in our Galaxy; map the invisible material (known as dark matter), which makes up the majority of our Galaxy (using samples of very rare stars uncovered in the survey; and uncover the first quasars and stars to form in the history of the Universe.

It will also help us locate future target stars and galaxies, which will be further investigated using the next generation of extremely large optical telescopes like the Giant Magellan Telescope and state of the art radio astronomy facilities such as the Australian Square Kilometer Array Pathfinder and in the future, the Square Kilometer Array.

iSGTW: What do you think are the most exciting projects in radio astronomy at the moment?

Schmidt: I think the ability to look at the epoch of reionization - the time when stars and galaxies lit up the Universe for the first time - is a really interesting radio project. Neutral hydrogen emits a 21cm radio signal, which we hope we can detect from all the stuff in the Universe before it got ionized. Seeing the Universe's hydrogen gas before it got ionised would chronicle how the stars and galaxies formed out of a quiescent sea of hydrogen and helium back some 13.5 billion years ago - a few hundred million years after the big bang.