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Milky Way has a huge void in the middle with no stars in it, scientists find

Published 03/08/2016

The Milky Way has a huge, gaping void inside of it that nobody had spotted before.

Scientists claim that our understanding of the Milky Way needs a re-evaluation after an international team found a region at the centre of our own galaxy that has no young stars.

The Milky Way is made up of many billions of stars, including our Sun. We sit about 26,000 light years from its centre.

But scientists are keen to find out how the rest of the stars are distributed throughout the galaxy.

To do that, they look for pulsating stars called Cepheids, which are ideal because they are much younger than our sun and pulsate in a regular cycle. Scientists can monitor that cycle to see how bright the star really is, compare it with how bright it looks from Earth, and use those two things to work out how far away it is.

But when they looked for those Cepheids in the centre of our galaxy, they found hardly any. There is a huge part of of space that stretches 8000 light years from the centre of our galaxy that scientists say is a “desert”.

"We already found some while ago that there are Cepheids in the central heart of our Milky Way (in a region about 150 light years in radius),” said Noriyuki Matsunaga of the University of Tokyo, who led the international team. “Now we find that outside this there is a huge Cepheid desert extending out to 8000 light years from the centre."

The findings appear to indicate that the Extreme Inner Disk that makes up a large part of our galaxy has no young stars.

“Our conclusions are contrary to other recent work, but in line with the work of radio astronomers who see no new stars being born in this desert,” said co-author Michael Feast in a statement.

It has been a desert for hundreds of millions of years, scientists say – and so we use now change how we understand how the Milky Way for was formed.

"The current results indicate that there has been no significant star formation in this large region over hundreds of millions years,” said another author Giuseppe Bono in a statement. “The movement and the chemical composition of the new Cepheids are helping us to better understand the formation and evolution of the Milky Way."

Scientists usually use Cepheids to work out the distance of objects in the far universe. But the new study shows them being used to work out the structure of our own galaxy, far closer to home.

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