Astronomers build first accurate map of the Milky Way galaxy

Astronomers from Macquarie University have discovered the true shape of the Milky Way galaxy.

A slightly exaggerated impression of the real shape of our warped and twisted Milky Way. Picture: Xiaodian Chen (National Astronomical Observatories, Chinese Academy of Sciences)

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Macquarie University astronomers have made an exciting discovery — revealing for the first time the true shape of the Milky Way galaxy.

Astronomers from the university and the Chinese Academy of Sciences discovered the Milky Way’s disc of stars becomes increasingly twisted the further away stars are from the galaxy’s centre.

Professor Richard de Grijs in the Macquarie University Observatory.

It was thought the Milky Way galaxy was flat and stable, but the first accurate 3D map of it shows a warped, S-shaped appearance in the far outer regions.

Astrophysicist and Macquarie University professor Richard de Grijs was the co-author of a paper released today detailing the discovery.

The 3D distribution of the classical Cepheid variable stars in the Milky Way’s warped disc (red and blue points) centred on the location of the sun (shown as a large orange symbol).

Access to a new catalogue allowed the team to determine the distances to a particular type of bright young stars called Cepheids with uncertainties of less than three to five per cent, helping the team create the first accurate 3D picture.

“That’s very high accuracy for astronomy — that’s as good as it gets basically,” Professor de Grijs said.

The 3D model shows that the collection of Cepheid stars closely follows the same spiral shape of the Milky Way’s gas disc.

“Perhaps more important, in the Milky Way’s outer regions, we found that the S-like stellar disc is warped in a progressively twisted spiral pattern,” Professor de Grijs said.

The discovery may help astronomers learn more about dark matter and where it exists.

Scientists have so far been unable to observe dark matter directly, but is understood to exist because of gravitational effects.

The latest discovery has added to what has been a fascinating few years in the field of astronomy.

“We have a lot of new facilities out there and more sophisticated approaches to doing science, and there’s a lot more happening,” Professor de Grijs said.