A new theory proposed by a scientist at the University of Oxford claims to explain the "missing" 95 per cent of the cosmos - the matter that physicists can't yet definitively account for.
According to the theory, dark energy and dark matter can be unified into a fluid possessing 'negative mass' or 'negative gravity', which repels all other matter around them.
Scientists believe that all the galaxies, stars, and planets seen in the universe make up just five per cent of it, and the remaining 95 per cent is made up of invisible, unknown substances, dubbed dark matter and dark energy.
So far, astronomers haven't been able to see or detect this mysterious stuff, and their existence is inferred only on the basis of their gravitational influence on other observable matter in the universe. Dark energy is thought to be a repulsive force that makes the universe expand at an accelerating rate.
The new model of 'negative mass' - proposed by Dr Jamie Farnes from the Oxford e-Research Centre, Engineering Science Department - is published in the journal Astronomy and Astrophysics.
"We now think that both dark matter and dark energy can be unified into a fluid which possesses a type of 'negative gravity', repelling all other material around them. Although this matter is peculiar to us, it suggests that our cosmos is symmetrical in both positive and negative qualities," said Farnes.
Some earlier studies have ruled out the existence of negative matter on the basis that it would become less dense during the expansion of the universe, which runs contrary to the observations demonstrating that dark energy does not dilute over time.
However, Farnes' theory of negative matter applies a 'creation tensor', which allows for continuous creation of negative masses. It shows that when more negative masses come into existence, the negative mass fluid does not become less dense during the expansion of the universe, and appears to be identical to dark energy.
Farnes' research also features a computer simulation which correctly predicts the formation and the behaviour of dark matter halos, just like the ones inferred by observations through advanced radio telescopes.
"There are still many theoretical issues and computational simulations to work through, and LambdaCDM has a nearly 30 year head start, but I'm looking forward to seeing whether this new extended version of LambdaCDM can accurately match other observational evidence of our cosmology," said Farnes.
"If real, it would suggest that the missing 95 per cent of the cosmos had an aesthetic solution: we had forgotten to include a simple minus sign."
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