UKZN’s newly appointed astrophysicist and senior lecturer in the Astrophysics and Cosmology Research Unit (ACRU), Dr Cynthia Chiang, is part of a team of experts that have made history with a groundbreaking result that will bring scientists one step closer to unraveling the mysteries of the universe.
Chiang is part of a team of 70 researchers involved in the creation of a high-sensitivity 10 meter telescope, valued at around R150 million, named the South Pole Telescope (SPT). SPT is the first telescope that has been successful in capturing a particular polarisation signal in the cosmic microwave background (CMB) of the universe. The CMB is the oldest discernible light we can observe in the universe, a light that allows scientists to shoot photographs of the universe in its infancy, 13.7 billion years ago, to a time when the ‘Big Bang’ is thought to have taken place. It is hoped that the successful result achieved by SPT will be a significant start in deciphering the mysterious dark matter that is thought to make up some 23 % of our universe.
In the collaboration centered at the University of Chicago, Chiang worked with a team of experts from about a dozen institutions in the US and Canada, to craft and operate the SPT. The project began in 2006, Chiang became involved in 2012, when a specialised new camera that could see polarised light was added to the telescope. This camera is what Chiang says was the key element in the success of the project, as it was sharp enough to capture the distortion observed. The SPT was set up to observe and capture the polarised CMB from the South Pole, Chiang spent 10 months there, observing and taking care of daily operations.
In the photos captured by the SPT, scientists were able to view a distortion caused by an effect called “gravitational lensing”, “When the CMB light is making its way through the universe it passes through lumps of matter, the light is deflected by the gravity from the matter, causing its propagation direction to change, SPT was able to see the distortion that bends light around the matter.” Chiang draws an example explaining that, “just as raindrops on a window pane can distort what we see outside of it, matter distorts our picture of the CMB by bending the light.”
Chiang says that by analysing the faint patterns in the CMB, scientists are working to gain insight into the inner workings of the universe and to understand the 96% of it that is made up of dark matter and dark energy.
Chiang describes what the SPT achieves as, “taking a photograph of the universe with polarised glasses on and observing the gravitational lensing, you can only discover it (the matter) by measuring, weighing up the contents through gravity and assessing the impact the matter has on its surrounding field.”
Chiang says that with its sharp focus and hyper-sensitive functionality the SPT can capture images that will help scientists understand where the mysterious matter lives and just how much of it there is.
Chiang is extremely excited and proud to be involved in this great discovery,
“It’s a wonderful feeling to know that the research I was involved in led to a real result,”
Chiang proves to be a unique and valuable addition to ACRU; skilled as a scientist with a flair for engineering, Chiang says she is excited about starting up UKZN’s first cosmology instrumentation lab.
“Apart from the great science potential, cosmology instrumentation also provides excellent training for students and young researchers; UKZN has a wonderful cosmology group, we have a lot of strength in theory and data analysis but the missing ingredient until now has been instrumentation and building hardware for these telescopes. I’m hoping to bring that to the university.”
Chiang is currently applying for funding to build up a lab that will develop sub-systems for microwave telescopes.
Chiang is originally from Illinois in the US, she completed a PhD at the California Institute of Technology, and she did her postdoctoral research at Princeton University and the University of Chicago.
Director of ACRU, Professor Sunil Maharaj, says Chiang’s research is very topical and relevant to the national thrust in astronomy and the many science projects taking place in South Africa.
“Her cutting-edge work has led to an upsurge in interest from our local students and will attract international researchers in joint collaborative research.”
The SPT team’s findings were recently published in the latest issue of Physics (The American Physical Society website); https://physics.aps.org/articles/v6/107