SOLVE magazine Issue 02 2021 - Page 18


Model of light

Scientists are attracted to questions without answers like moths to a light . It is a perpetual quest because answers lead to more questions – especially when you are trying to unravel the ultimate mystery : our place in the cosmos .

P rofessor Claudia Maraston sees herself as part of an irresistible continuum , one that began when the earliest humans pondered the night sky and will not end for eons to come , if ever . Her life and work are bound in the eternal questions : What is the universe ? How has it evolved ? What is its future ? Why are these questions being asked by a life form in a remote solar system in a small obscure galaxy in the universe ’ s outer suburbs ?

Big questions , shared by many – if not most – people , but as one of the world ’ s leading astrophysicists Professor Maraston has helped prise open some of the universe ’ s secrets that go part way to explaining who and what we are .
Put simply , she explains , we are a product of our home galaxy , the Milky Way , and its carbon and oxygen chemistry . Our Sun and its stellar neighbours have a similar chemical signature that reflects a specific stage in the universe ’ s evolution – about 10 billion years following the Big Bang .
“ Close to the Big Bang , there was no oxygen , just hydrogen and helium . The stars were very bright , much more than our Sun , but without metals they were much bluer . In that situation , biological life like ours was not possible ,” she explains . “ You needed a few billion years of fusion and nucleosynthesis [ the formation of progressively more complex atoms ] to create the elements that make up our galaxy and which are necessary for us to exist .”
This cosmic evolution , the turbulent transition from masses of gas to solid masses on an incomprehensible scale , is a fundamental platform in the science of astrophysics . Some of the key research tools used by astrophysicists and astronomers around the world are stellar population models conceived and developed by Professor Maraston when she was a PhD student , and which have subsequently been enhanced as computers have advanced : “ I developed the first model as part of my PhD . It ran on a small computer , but the models today run on supercomputers .”
These models are a theoretical construction of the physical and chemical processes that erupted following the Big Bang and the hydrogen fusion that started the progressive creation of new elements . They help researchers make sense of the data being collected from galaxy observations by providing a research framework for the evolutionary processes that galaxies have undergone over billions of years .
Knowledge building The never-ending excitement for Professor Maraston is the fact that her models are continually validated , and improved , by the science and the data accrued as observational technologies – including the recent detection of gravitational waves – have advanced .
Along the way , as with any scientist pushing frontiers , she has attracted accolades and criticism in probably equal measure . But it is when she is challenged that she most thrives .
“ In astrophysics , you can ’ t fear
ISSUE 02 / 2021