Mind over matter

It cannot be seen or felt, but a Monash University astro-particle physicist says dark matter must exist.

Monash researchers are part of a worldwide race to prove the theory that most of the universe is predominantly made up of particles we can't see and that dark matter is, in fact, all around us.

Imagine if everything we could see, in fact everything visible throughout the cosmos, made up only five per cent of the total number of particles in existence. That 95 per cent of our universe was invisible and undetectable.

It is a mind-bending proposition, supported by Dr Csaba Balazs of Monash University's School of Physics, within the Faculty of Science. Dr Balazs has dedicated his career to proving the existence of the unseen particles, known as dark matter.

Dr Balazs researched astrophysics at the University of Chicago for many years before joining Monash and has recently been awarded an Australian Research Council grant to continue his work in Australia.

"Dark matter is unseen because it doesn't reflect light. We don't know what it's made of, but we know it's there. As we learn more about it, the more fascinating it becomes," Dr Balazs said.

Dark matter is theoretical matter of unknown composition that does not emit enough electromagnetic radiation to be observed directly, but whose presence can be inferred from gravitational effects on visible matter such as stars and galaxies.

If the current rules of gravity are applied to far off galaxies, then scientists say there must be a missing mass, which has been labelled dark matter. It cannot be seen (it doesn't reflect or emit light) but has mass and thus say scientists must exist.

While the concept was first theorised in the 1930s, the bulk of the research around dark matter has taken place in the last decade. Dr Balazs notes that all scientific theories must start somewhere.

"Consider that just 150 years ago we did not understand the nature of electromagnetic radiation. Today we could not function normally without electricity to drive our computers, our cars, our homes and workplaces," he said.

Dark matter technically remains a scientific theory, but Dr Balazs said there was extensive scientific evidence to show it does exist. The theory started with the observations of Swiss scientist, Professor Fritz Zwicky, who worked through some complex mass measurement problems of the universe.

"He found that for all the visible components in the galaxies to behave the way they do, there must be some 'missing mass' -- that it wasn't possible for the gravitational forces to interact in such a way without there being extra influences," Dr Balazs said.

Either there's dark matter everywhere or Einstein's theory of gravity is wrong!
Dr Csaba Balazs

Not everyone is convinced. Other scientists say there is no dark matter and we simply do not yet fully understand the laws of gravity.

Dr Balazs is continuing to work on dark matter theories with a small team of PhD students at Monash. And if the theory is proven correct, it could, like mankind's understanding of the electromagnetic theory, create fundamental changes to our lives.

"The potential implications of dark matter are beyond comprehension. I can't say what may evolve when dark matter is identified, but I'm sure that the scientific and social consequences will be remarkable," Dr Balazs said.

Visit the School of Physics website.