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Past Winner
2008 E.W.R. Steacie Memorial Fellowship

Barth Netterfield


University of Toronto

Barth Netterfield
Barth Netterfield

Barth Netterfield likes to play with balloons, but not just any balloons. Sporting names like BOOMERANG, BLAST and Spider, his toys travel far up into the stratosphere carrying sophisticated telescopes that gather data about the origins of the universe nearly 14 billion years ago.

In collaboration with colleagues from around the world, his balloon experiments study such phenomena as the process of star formation and the characteristics of the cosmic microwave background (CMB), which is the leftover radiation signature of the Big Bang. Dr. Netterfield is one of the top experimental cosmologists in the world, and his work on these types of astronomical phenomena has earned him an NSERC E.W.R. Steacie Memorial Fellowship.

Dr. Netterfield explains that studying the universe is effectively a history lesson. The light that reaches us tells us not what things look like today, but what they looked like when that light left a distant galaxy. Studying the CMB, which dates from the first 300,000 years or so after the Big Bang, therefore requires looking at very furthest reaches of the known universe.

He adds that while the CMB began as light generated by plasma (glowing gases with a temperature around 3000°C), it does not appear now as visible light due to the Doppler shift. That’s the same phenomenon that makes a siren sound higher-pitched when it approaches and lower-pitched as it moves away. If the source of sound or light waves is moving away from the observer, the waves will lengthen and frequency reduce.

Since the furthest galaxies are moving away from us at almost the speed of light, any radiation coming from them undergoes a sufficient Doppler shift to drop it well down through the infrared spectrum, to microwaves. In fact, when scientists were first able to detect the CMB in 1964, they found that it radiated the equivalent energy of a body that is just a few degrees warmer than absolute zero, or about minus 270°C.

Dr. Netterfield has played a key role in a number of recent efforts to unlock more of the universe’s secrets, including BOOMERANG (Balloon Observatory of Millimetric Extragalactic Radiation and Geophysics). Among other things, that project’s results identified the energy density and geometrical characteristics of the universe, calculated the age of the universe more accurately than ever before, and in many ways clinched the theory that the universe is made up primarily of dark matter and dark energy.

Cutting-edge research into the CMB involves a combination of ground-based observatories, satellites and the balloon-borne telescopes that Dr. Netterfield is an internationally renowned expert in designing and building. In addition to his work on the hardware, he designs control software and helps develop new analytical techniques.

One of the reasons he gravitates towards balloons is that they are relatively cheap, reusable and can be built quickly. “The satellites will be better, but we’ll be first,” he says. Another advantage lies in the fact that results can be achieved quickly enough for graduate students to participate in every stage of a research project. “For a university setting, balloons are fantastic,” he adds. “They are THE training ground for doing space-related science projects.”

Even though they are cheap compared to many astrophysics projects, balloons still require contributions from multiple institutions and researchers to get them off the ground. And the teamwork continues after the data is gathered. Dr. Netterfield points out that a recent flight of the BLAST (Balloon-borne Large Aperture Sub-millimetre Telescope) yielded more data than his research group can process, including the fascinating discovery of hundreds of protostellar cores – cores that will eventually collapse to form large stars. “Right now, we’re really keen to get the data released so that people can use it,” he says. “But, we do want to get the first papers out. It’s always a balance. It’s a very excellent data set and there’s a lot of science that can be done with it.”

Dr. Netterfield is known for his willingness to share information, although he recognizes that in a competitive scientific environment there are risks associated with giving knowledge away. “I want to think about it in terms of what’s best for science,” he says. “At the end of the day we’re trying to make an impact. And a good way to make impact is to give stuff away.” That generosity also extends to sharing the software that he develops for experiments if he feels it could be useful to others.

One of the challenges he will take on during his Steacie Fellowship is to try to solve the next CMB mystery. The theory of inflation, which is a refinement of the Big Bang theory, argues that the universe initially expanded faster than the speed of light. It follows that there should be a cosmic gravitational wave that can be detected through a specific polarization in the CMB. The Spider balloon borne experiment (named for the original shape of the apparatus), which Dr. Netterfield hopes to launch in 2009, will feature highly sensitive equipment designed to search for this signal.

If Spider is successful, it will allow astronomers to look even further back in history at events that occurred a minute fraction of a second after the Big Bang. Of course, that would only raise more questions about what happened when the universe formed, but Dr. Netterfield welcomes the challenge.