Our Milky Way galaxy is truly warped

James Marshall
February 8, 2019

An Australian and Chinese collaboration has created the most accurate 3D model so far of the Milky Way, showing the galaxy to be curved rather than a flat disc shape.

It turns out that the further the stars are from the center of the galaxy, the weaker their gravitational pull is.

"It is notoriously hard to determine distances from the Sun to parts of the Milky Way's outer gas disc without having a clear idea of what that disc actually looks like", said Xiaodian Chen from the Chinese Academy of Sciences in Beijing.

The stars on which his team's map is based - known as classical Cepheids - provided substantial measuring accuracy. That database allowed the team to develop the first accurate three-dimensional picture of our Milky Way out to its far outer regions.

Nevertheless, its shape is not unique, as scientists have observed different galaxies in the universe which showed similar spiral patterns to the Milky Way. Such high stellar masses imply that they live fast and die young, burning through their nuclear fuel very quickly, sometimes in only a few million years.

"We usually think of spiral galaxies as being quite flat, like Andromeda which you can easily see through a telescope", said Professor Richard de Grijs from Macquarie University in Australia.

"Somewhat to our surprise, we found that in 3D our collection of 1339 Cepheid stars and the Milky Way's gas disc follow each other closely".

The Milky Way turned out to be progressively twisted in its outer areas, which is most likely caused by the powerful rotating forces released by the galaxy's massive internal disk, according to the research.

Chen Xiaodian, the lead author of the study and a researcher at the National Astronomical Observatories of Chinese Academy of Sciences, said that accurate distances from the Sun to parts of the Milky Way's outer disc were key to knowing what that disc actually looked like.

Dr. Liu Chao, senior researcher and co-author of the paper said that the researchers observed other "warped" spiral galaxies.

Other reports by Click Lancashire

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