A team of scientists at the University of Oxford may have solved one of the biggest mysteries in modern physics - the issue of dark matter and dark energy in the universe.

Scientists have long suspected there is more material in the cosmos than we can observe and 95% is made up almost entirely of invisible, unknown material dubbed dark energy and dark matter.

The mysterious dark substances are not covered by the existing mathematical model of the universe - known as LambdaCDM - but they are known to exist because of their gravitational effects.

Now scientists have proposed a new model which unifies dark energy and dark matter into a single phenomenon - a fluid which possesses "negative mass".

Dr James Farnes, who led the team at Oxford's e-Research Centre, said: "We now think that both dark matter and dark energy can be unified into a fluid which possesses a type of 'negative gravity'.


Image: Dark energy and dark matter are known to exist due to their gravitational effects

"If real, it would suggest that the missing 95% of the cosmos had an aesthetic solution: we had forgotten to include a simple minus sign."

The idea of negative matter was previously ruled out because it was thought the material would be less dense as the universe expanded - something which observations involving dark matter did not support.

However the Oxford team applied a new "creation tensor" to the model which allowed for negative masses to be continuously created.

The tensor demonstrates that when more and more negative masses burst into existence, the new material - the negative mass fluid - does not become diluted due to the universe's expansion.

The theory provided the first correct prediction of the behaviour of dark matter halos - the material which holds galaxies together.

Galaxies rotate so rapidly that the basic laws of physics suggest they should tear themselves apart and dark matter halos are what is believed to keep them together.

The Oxford team's research features a computer simulation of the properties of negative mass which predicted the formation of dark matters halos exactly matching ones which radio telescope observations suggest exist.

The proof of Dr Farnes' theory will come via tests conducted through enormous radio telescopes, including the Square Kilometre Array, which the University of Oxford is involved in developing.

:: Dr Farnes' research is published in the Astronomy and Astrophysics journal.