THERE is an awful lot of it about but what it is remains the "most profound mystery in science", says the man who gave it its name: dark energy.

This weird, invisible force that is pushing the galaxies apart at a faster and faster rate accounts for almost three-quarters of the universe, the University of Chicago cosmologist Michael Turner said yesterday.

"It's very different than anything else we know," Professor Turner, who was attending a conference in Canberra, said. "Until we understand what dark energy is, we don't understand the destiny of the universe."

The mystery is no surprise. The existence of dark energy was revealed 11 years ago by two teams, one led by the Australian astronomer Brian Schmidt, who discovered the expansion of the universe was accelerating.

Australian astronomers are also now leading the way in throwing light on this dark side of the cosmos.