Article Posted on : - Aug 12, 2012

A file photo.

LONDON (PTI): Scientists have claimed that the Sun is surrounded by dark matter, a phenomenon first proposed in the 1930s by a Swiss astronomer.

Researchers from the University of Zurich have developed a new theory - and built a simulation of the Milky Way to test their mass-measuring method before applying it to real data, the 'Daily Mail' reported.

"We are 99 per cent confident that there is dark matter near the Sun," lead author Silvia Garbari was quoted as saying by the paper.

The study claims that the techniques used over the past 20 years were biased, always tending to underestimate the amount of dark matter in the universe.

"This could be the first evidence for a 'disc' of dark matter in our Galaxy, as recently predicted by theory and numerical simulations of galaxy formation, or it could mean that the dark matter halo of our galaxy is squashed, boosting the local dark matter density," Garbari said.

The researchers then developed a new unbiased technique that recovered the correct answer from the simulated data.

Applying their technique to the positions and velocities of thousands of orange K dwarf stars near the Sun, they obtained a new measure of the local dark matter density.

"Experimental physicists hope to capture just a few of these particles each year in experiments like XENON and CDMS currently in operation," study co-author George Lake said.

Fritz Zwicky, who came up with the theory decades ago, believes that clusters of galaxies were filled with a mysterious dark matter that kept them from flying apart.

Around that time, Jan Oort in the Netherlands discovered that the density of matter near the Sun was nearly twice what could be explained by the presence of stars and gas alone.

"Knowing the local properties of dark matter is the key to revealing just what kind of particle it consists of," Lake added.