For most of the past three years, the two emeritus professors from the southern and northern hemispheres, respectively, have been living half a world apart.
But that has not stopped them joining forces to jointly research and write a book on the evolution of the universe, titled Physics Evolution God: Mass and Nomass.
Their research investigated how mass and "nomass"- the latter including ideas and concepts- had evolved.
Physics, evolution, and a concept of God were all "integral to the universe", Prof Sigmon said.
The project started after the two academics met by chance in Dunedin in 2007.
That year Prof Sigmon spent several months in Dunedin, giving some seminars at Otago University and rethinking her future research direction, having recently become an emeritus professor at Toronto University after a lengthy career.
As the shared project later developed, she found it "enlightening" to work closely with a physicist, someone from an entirely different academic discipline.
They found they were ultimately "really not so different" and were willing to learn basic aspects of each other's disciplines.
She was studying five million to 60 million years of human evolution and he was striving to understand the beginning of the universe, 13.7 billion years ago.
They communicated initially through email and telephone, and then switched to Skype, enabling them to show each other text and diagrams at a distance.
Palaeoanthropologists - evolutionary biologists who specialise in human evolution - were "a bit like prehistoric forensic scientists".
"We can tell you what our fossil ancestors as early as five million years ago looked like and acted like, what they ate, their age at death, their gender and sexual patterns, sometimes even their beliefs and social customs," she said.