4 mins read 25 Feb 2021

Neutrinos from ANSTO might break Time Dilation Rules

Researchers from Griffith University have teamed up with ANSTO to test whether neutrinos from a nuclear reactor can cause time dilation at the quantum scale.

Lou Marais (NMI), Michael Wouters (NMI) and Professor Erik Streed next to one of the timing stations with atomic clocks. Credit: ANSTO.

Time is a surprisingly complex concept in the field of physics. The speed at which time passes is not always constant, in accordance to how time is described as an integrated dimension with space, through Einstein’s theories of relativity - where mass and velocity (in a relativistic sense) can play a vital role.  

Now, a new experiment from Griffith University and the Australian Nuclear Science and Technology Organisation (ANSTO) is set to see if time can be affected by neutrinos, which may potentially affect the orbits of planets and other bodies around the Sun. 

The experiment is based on a theory that was originally presented by Professor Joan Vaccaro, who puts forward the idea that everything we think we observe as changes over time are in fact not a fundamental part of nature, but instead emerge from the phenomena known as time symmetry violations. 

If this complex theory were true, it has the potential to significantly change how we think of time, space, and fundamental laws of physics. Researchers from Griffith University, including Professor Erik Streed, have teamed up with the ANSTO to take on the experimental task of testing the validity of Vaccaro’s theory. 

“My colleague’s [Vaccaro’s] calculations suggest that neutrinos may have a greater impact on time than we realise,” said Streed. “It would be very surprising indeed if neutrinos were interacting with matter on the basis of time”

Neutrinos versus Time Symmetry

Time doesn’t just run from point A to point B at a constant speed; there are many things that can affect it. Credit: andrey_l/Shutterstock.

Neutrinos, the cornerstone of Streed’s experiment, are subatomic particles that have no electrical charge. One of the defining qualities of the neutrino is that it interacts very little with matter, making it incredibly difficult to detect. Neutrinos can be made from the processes of nuclear fusion (the joining of atoms, seen in stars) or fission (the splitting of atoms, used at most nuclear reactors). 

Neutrinos also appear to have an interesting relationship with time, with some scientists claiming that evidence that neutrinos exhibit time symmetry violation has been growing in recent years and currently stands at 99.7% certainty. Time symmetry in physics is the idea that the laws of physics should look the same whether time runs forwards or backwards. But, neutrinos don’t appear to fit this, making them important in the testing of Vaccaro’s theory.

Testing Vaccaro’s Theory

Stars (including the Sun) are sources of neutrinos due to their nuclear fission. Vaccaro’s theory suggests that the neutrinos from these stars may have an impact on the timing of planetary orbits. Credit: European Southern Observatory.

Streed’s experiment is one that was suggested by Vaccaro in her theory. The experiment involves placing two clocks near a nuclear reactor, one 5 metres away and one 10 metres away. The clocks are atomic clocks and their measuring methods are provided by the Australian National Measurement Institute (NMI). 

The reactor Streed will be using is ANSTO’s OPAL (Open Pool Australian Lightwater) fission reactor. The reactor releases neutrinos during the fission (splitting) of Uranium-235 atoms. Uranium-235 undergoes fission when it absorbs a neutron, which causes the atom to become unstable and split, producing atoms and energy. Some of this energy takes the form of neutrinos. 

In theory, the clock closest to the reactor should experience time dilation (difference in elapsed time) due to its proximity to the neutrinos produced by the reactor and their time reversal symmetry violation. The further clock would not experience this dilation, and therefore comparing the data between the two clocks would provide a “number” for how big the quantum effect on time is. 

The next step, if the results from the OPAL experiment look promising, is to look at other sources of this time symmetry violation, such as the Sun and the planets that orbit it.