Supercomputer Shows “Chameleon Theory” Could Change How We Think About Gravity

Supercomputer simulations of galaxies have shown that Einstein’s theory of General Relativity might not be the only way to explain how gravity works or how galaxies form.

Chameleon Theory
A computer- generated image of the simulated galaxy with the gas density shown as bright dots (Credit: Christian Arnold/Baojiu Li/Durham University)

Physicists at Durham University supported by STFC have simulated the cosmos using an alternative model for gravity – f(R)-gravity, a so called Chameleon Theory.

The resulting images produced by the simulation show that galaxies like our Milky Way could still form in the universe even with different laws of gravity.

The findings show the viability of Chameleon Theory – so called because it changes behaviour according to the environment – as an alternative to General Relativity in explaining the formation of structures in the universe.

The research could also help further understanding of dark energy – the mysterious substance that is accelerating the expansion rate of the universe.

Research co-lead author Dr Christian Arnold, in Durham University’s Institute for Computational Cosmology, said: “Chameleon Theory allows for the laws of gravity to be modified so we can test the effect of changes in gravity on galaxy formation.

“Through our simulations we have shown for the first time that even if you change gravity, it would not prevent disc galaxies with spiral arms from forming.

“Our research definitely does not mean that General Relativity is wrong, but it does show that it does not have to be the only way to explain gravity’s role in the evolution of the universe.”

The findings are published in Nature Astronomy and you can read more about the research here.