Dark matter estimates in Milky Way are way off, says new research

9 Oct 2014

The constellation Fornax is a satellite of our Milky Way. Image via ESO/Digital Sky Survey 2

Astronomers who have developed a new method of measuring the amount of dark matter in the universe have shown that previous estimates have been off by as much as 50pc.

The research is part of a paper published in The Astrophysical Journal, which documented how a team of Australian astronomers developed a new method of calculating the little-understood material dark matter in our galaxy.

According to their figures, the weight of all dark matter within our galaxy, the Milky Way, is a mind-blowing 800,000,000,000 times the mass of our own sun. The scope of the astronomers’ research extends as far as 5bn km from Earth.

Using their new measurement, they have been able to find that all the material that makes up planets, stars and other objects accounts for 4pc, while dark matter now only accounts for 25pc, with the remainder being made up of dark energy.

The lead on the project, Dr Prajwal Kafle, and his team developed the new measurement by examining the speed stars are travelling within our galaxy, including the edges, which proved to be a first in dark matter measurement and seemingly challenges previous estimates.

A fellow astrophysicist at the University of Sydney said Kafle’s discovery had finally answered a question that has been a “thorn in the cosmological side for almost 15 years”.

Explaining the importance of his team’s new scale of measurement, Kafle said, “When you use our measurement of the mass of the dark matter, the theory predicts that there should only be three satellite galaxies out there, which is exactly what we see; the Large Magellanic Cloud, the Small Magellanic Cloud and the Sagittarius Dwarf galaxy.”

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Colm Gorey was a senior journalist with Silicon Republic