Milky Way's 250 billion stars are 'warped and twisted', new 3D model suggests

Astronomers have presented a twist on how we see our galaxy, the Milky Way, with a new three-dimensional map.

The galaxy was generally thought to be a flat disc consisting of an estimated 250 billion stars, but fresh analysis suggests it is more warped and twisted.

Looking at the distance of some of the brightest, pulsating stars in the Milky Way, known as Cepheids, scientists at the University of Warsaw were able to build a large-scale 3D model of the galaxy.

"Cepheids are ideal to study the Milky Way structure, because they follow a relation between their pulsation period and their luminosity, meaning that we can measure their intrinsic brightness based on their period," said Dr Dorota Skowron, first author of the research published in the Science journal.

"The distance can then be determined by comparing the apparent and intrinsic brightness of the star."

Scientists searched for stars that change their brightness in a specific pattern using a telescope in Chile to image the entire visible Milky Way more than a hundred times.

They say that warping may have been caused by past interactions with smaller galaxies within the Milky Way called satellite galaxies, or as a result of intergalactic gas and dark matter.

Their research supports similar findings revealed in February.

Przemek Mroz, a member of the Optical Gravitational Lensing Experiment (OGLE) at Las Campanas Observatory (LCO) in Chile, said: "Our three-dimensional map of the Milky Way is the first map that is based on direct distances to thousands of individual objects, as distant as the expected boundary of the Galactic disk.

"Our map shows that the Milky Way disk is not flat, it is warped and twisted far away from the Galactic centre.

"Warping of the Galactic disk has been detected before, but this is the first time we can use individual objects to trace its shape in three dimensions."

PA