DESPITE it being invisible, dark matter has been placed on the galactic map by astronomer Ken Freeman — in the process placing him among international astronomy's brightest stars.
Professor Freeman's work established there is substantially more to galaxies than can be seen by the human eye. In fact, the stars, gasses and dust are just a fraction of what is out there. The bulk is invisible, dark matter.
First outlined in a paper in 1970, Professor Freeman's research was not without its critics. "I don't think any of the papers of that period were received with total enthusiasm but that's kind of how it should be," he said.
"It was overturning the existing paradigm and it really took most of that decade for it to happen."
Already regarded internationally as Australia's most renowned astronomer, Perth-born Professor Freeman, from the Australian National University's Mount Stromlo Observatory, was awarded the $300,000 Prime Minister's Prize for Science on Wednesday for introducing the concept of dark matter, a finding that changed the course of astronomy.
Dark matter accounts for the vast majority of the universe, but scarcely anything is known about it. Yet dark matter really does matter: it plays a crucial role in holding the universe together, given its almost magnetic powers.
"The reason we should know about dark matter is because it was so important in the formation of the universe as we know it now," Professor Freeman, 72, said. "If it wasn't for dark matter, we may well not have galaxies at all because things may not have condensed to form the Milky Way, for example."
Professor Freeman's award, presented in the Great Hall of Parliament House in Canberra, also recognises his contribution as co-founder of one of the hottest fields in astronomy: galactic archaeology.
It's a field he and colleague Joss Bland-Hawthorn had been pondering since 1988, but it wasn't until 2002 that the pair published a paper on the subject, which looks at how galaxies are constructed by analysing their chemical composition.
Other winners on Wednesday included Mark Shackleton from the Peter MacCallum Cancer Centre in Melbourne, who received the life scientist of the year award for his work on breast cancer and melanoma.
The University of Western Australia's Eric May received the physical scientist of the year award for his work on making liquid natural gas a cleaner resource.