Astronomers build most accurate 3D map of 'warped and twisted' Milky Way


The study's breakthrough moment came by observing Cepheids - massive, super bright stars with short life spans.

Burning their fuel quickly, those pulsating stars that live fast and die young are 100,000 times brighter than the Sun.

Using these hotheads as benchmarks, scientists were able to map out accurate distances between objects in the Milky Way. The units "kpc" (kiloparsecs) along the image's three axes are used by astronomers to indicate distances on galaxy-wide scales.

It was only in recent centuries that it became an established scientific fact that Earth orbits the sun, and later that the solar system - along with hundreds of billions of other stars - orbits a common galactic center.

"We usually think of spiral galaxies as being quite flat, like Andromeda, which you can easily see through a telescope", Macquarie University's Richard de Grijs, who took part in the study, said in a statement from Sydney. The new data also add a literal twist to the story, showing that the warp precesses, or turns. The new map shows that the warped Milky Way disc also contains young stars.

"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", says Xiaodian Chen, lead author, from the Chinese Academy of Sciences in Beijing.

Now the first accurate 3D map of its kind published in Nature Astronomy reveals they were right. Since a Cepheid's period tells astronomers how bright the star truly is, measuring how bright it appears lets astronomers draw an accurate distance map.

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"This offers new insights into the formation of our home Galaxy".

This isn't completely abnormal, because astronomers have noticed the same pattern of progressively twisting spirals in about a dozen other galaxies.

Scientists have known since the 1950s that the spiral-shaped Milky Way's disk is warped, bending by thousands of light-years at its outskirts.

Researchers from Macquarie University, Australia, and the Chinese Academy of Sciences made their findings after creating a new 3-D map of the Milky Way, which allowed them to better estimate its shape.

This is the mysterious invisible material that provides the gravitational "glue" that holds galaxies together.

"We concluded that the Milky Way's warped spiral pattern is most likely caused by "torques" - or rotational forcing - by the massive inner disk", says Dr. Liu Chao, senior researcher and co-author of the paper.

The resulting resource enabled the team to predict that the hydrogen gas in the outer reaches of the disk was not confined to a thin plane but would actually appear like a warped S-shape if observed from a distance.