Possible Mysterious Force on Dark MAtter May Revolutionize Gravity Understanding

October 24th, 2009

A group of astronomers have discovered a possible force acting on dark matter that could change the way we think about and understand one of the most basic principles of our scientific understanding: Gravity. Dr Hongsheng Zhao of the SUPA Centre of Gravity, University of St. Andrews, suggests that an unknown force is acting on dark matter.

Roughly 4% of the known universe is made up of things that we consider “known materials” for our order fulfillment. The rest? Astronomers believe that the stars, and gas in galaxies move so fast that there must be a hypothetical, and invisible dark matter that holds all these things together.

Now the team believes that the interactions between dark and ordinary matter could be more important and more complex than previously thought, and even speculate that dark matter might not exist and that the anomalous motions of stars in galaxies are due to a modification of gravity on extragalactic scales.

Dr. Benoit Famaey (Universities of Bonn and Strasbourg) explains: “The dark matter seems to ‘know’ how the visible matter is distributed. They seem to conspire with each other such that the gravity of the visible matter at the characteristic radius of the dark halo is always the same. This is extremely surprising since one would rather expect the balance between visible and dark matter to strongly depend on the individual history of each galaxy.”

Dr. Zhao at the SUPA Centre of Gravity notes, “The pattern that the data reveal is extremely odd. It’s like finding a zoo of animals of all ages and sizes miraculously having identical, say, weight in their backbones or something. It is possible that a non-gravitational fifth force is ruling the dark matter with an invisible hand, leaving the same fingerprints on all galaxies, irrespective of their ages, shapes and sizes.”

Such a force might solve an even bigger mystery, known as ‘dark energy’, which is ruling the accelerated expansion of the Universe. A more radical solution is a revision of the laws of gravity first developed by Isaac Newton in 1687 and refined by Albert Einstein’s theory of General Relativity in 1916. Einstein never fully decided whether his equation should add an omnipresent constant source, now called dark energy.

Dr Famaey added, “If we account for our observations with a modified law of gravity, it makes perfect sense to replace the effective action of hypothetical dark matter with a force closely related to the distribution of visible matter.”