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While we're still yet to find concrete evidence it exists, scientists now think there might be half as much dark matter in the Milky Way as previously thought.

By observing stars at the edge of the galaxy, astronomers claim we may have overestimated how much we should expect to find.

And the discovery could also help explain another mystery of our galaxy - namely why it has so few other galaxies in orbit around it.

Astronomers at the University of Western Australia studied our Milky Way (illustration shown). They found the mass of dark matter should be 800 billion suns. This is half what the previous estimate for dark matter in the galaxy was. The discovery helps solve a mystery as to why we had so few satellite galaxies

Australian astronomers used a method developed almost 100 years ago to discover that the weight of dark matter in our own galaxy is 800 billion times the mass of the sun - half what was previously thought.

They probed the edge of the Milky Way, looking closely at the fringes of the galaxy about three trillion miles (5 trillion kilometres) from Earth.

To make the discovery, they used a robust technique developed by British astronomer James Jeans in 1915 - decades before the discovery of dark matter.

It involves measuring the speed of stars moving through the galaxy. 

Astrophysicist Dr Prajwal Kafle, from The University of Western Australia node of the International Centre for Radio Astronomy Research, said we have known for a while that most of the Universe is hidden.

'Stars, dust, you and me, all the things that we see, only make up about 4 per cent of the entire universe,' he said.

'About 25 per cent is dark matter and the rest is dark energy.'

Dr Kafle, who is originally from Nepal, was able to measure the mass of the dark matter in the Milky Way by studying the speed of stars throughout the galaxy, including the edges, which had never been studied to this detail before.

Earlier this year, in separate research scientists created the most detailed computer simulation of the history of the universe called Illustris, revealing dark matter density in the universe (illustrated here). The simulation was developed by a team led by astrophysicist Mark Vogelsberger of Massachusetts Institute of Technology

Dr Kafle's measurement also helps to solve a mystery that has been haunting theorists for almost two decades.

'The current idea of galaxy formation and evolution, called the Lambda Cold Dark Matter theory, predicts that there should be a handful of big satellite galaxies around the Milky Way that are visible with the naked eye, but we don't see that,' Dr 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.'

University of Sydney astrophysicist Professor Geraint Lewis, who was also involved in the research, said the missing satellite problem had been 'a thorn in the cosmological side for almost 15 years.'

'Dr Kafle's work has shown that it might not be as bad as everyone thought, although there are still problems to overcome,' he said.

The study also presented a broader model of the Milky Way, which allowed the scientists to measure several interesting things such as the speed required to leave the galaxy.

'Be prepared to hit 3640 miles [550km] per second if you want to escape the gravitational clutches of our galaxy,' Dr Kafle said.