Space and time
Scientist suggests that time moving forward may not be a natural part of physicslunanaranja/iStock

Our ideas about time and the "direction" it moves in may need to go back to the drawing board, says physicist Joan Vaccaro, from Griffith University in Queensland. She suggests the traditional view of movement through the space-time continuum as having always simply existed is perhaps not correct.

It is generally understood that there is a link between time and space – albeit the link is that there is no link. An object can move forward in time, but that does not necessarily mean it has to move in space. This idea is known as the asymmetry of time and space.

In a paper published in the Proceedings of the Royal Society A, Vaccaro said the evolution of time began when the asymmetrical link between space and time was violated at one point in the past. Vaccaro says time moves in one direction because subatomic particle decay breached the link between time and space long, long ago.

"For example, a rock that exists now, likely existed a million years ago and it will continue exist for another million years," Vaccaro told IBTimes UK. "The underlying idea is that the rock is being transported over time. However, you can leave the rock in a certain position in space and it will happily stay there."

"What I am saying is that that dynamics [the way objects move through time and space] is not a fundamental feature of the universe, as currently thought. Rather dynamics is due to the universe having the property of T violation." T violation is the name given to the action of subatomic particles violating the movement of time.

Vaccaro suggests something must have happened long ago to make this asymmetry. She says subatomic particle decay may have upset the balance in time reversal symmetry. The decay then would have disrupted it, eventually changing the system to the one we are in now.

Her study does not pinpoint these violations, but looks for the consequences of them. She writes: "The aim is not to study specific instances of the violations as observed experimentally, but rather to look for possible consequences of the violations in general terms. As such, T violation [the disruption of time reversal symmetry] is seen as being responsible for fundamental differences between space and time in conventional quantum mechanics."

To find this, Vaccaro created a new sum-over-paths formalism; a type of model which followed an infinite number of solutions, each with different probabilities. Combined with the Schrödinger equation – which describes the probability of certain particles moving, and how that probability evolves over time – she discovered the disruption in T symmetry.

"I use a new model of the universe which treats time and space symmetrically. For example, using this model I can place a galaxy at a set position in both time and space and it will happily stay put at that position and only that position," she said.

"The interesting thing is this. If I include a property called 'T violation' in the model of the universe, the galaxy remains fixed at the set position but now it does not remain fixed at the set time. Instead the galaxy appears at every time prior to and following the set time."