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Trending Science: Our galaxy is warped and twisted

A new map of the Milky Way reveals its strange twisted shape, far from flat as was believed till now.

Space

Forget about academic literature and popular culture. The Milky Way, our own galaxy, isn’t really the flat disk shape everyone thought it was. A new 3D map confirms that the Milky Way’s star-studded disk is twisted and warped. Our solar system is inside the disk, about 27 000 light years from the centre. The Polish research team responsible for the discovery published its findings and the accompanying map in the journal ‘Science’. Created by the researchers themselves, the map is the most precise to date of the Milky Way. “For the first time, our whole galaxy - from edge to edge of the disk - was mapped using real, precise distances,” University of Warsaw astronomer and study co-author Prof. Andrzej Udalski told ‘Reuters’. A big twist To gain insight into the shape of the Milky Way, the astronomers measured the distances of Cepheids. “Cepheids are ideal to study the Milky Way for several reasons,” added lead author Dr Dorota Skowron, also an astronomer at the University of Warsaw. “Cepheid variables are bright supergiant stars and they are 100 to 10,000 times more luminous than the sun, so we can detect them on the outskirts of our galaxy. They are relatively young - younger than 400 million years - so we can find them near their birthplaces.” In addition, Cepheids pulsate at frequent periods at a rate that’s directly associated with their brightness. This allows astronomers to calculate their distance with great accuracy. The Cepheids enabled Dr Skowron and her team to create a 3D map that relied on the measurements of more than 2 400 Cepheids, many of which were newly identified by data collected mainly using an observatory’s telescope in Chile. The map showed that the galaxy’s disk is considerably warped and varies in thickness from place to place, with increasing thickness measured further from the galactic centre. Our galaxy’s heart is totally twisted Speaking to the ‘BBC’, Dr Skowron explained: “The internal structure and history of the Milky Way is still far from being understood, in part because it is extremely difficult to measure distances to stars at the outer regions of our galaxy.” She clarified further: “Our results show that the Milky Way Galaxy is not flat. It is warped and twisted far away from the galactic centre. Warping may have happened through past interactions with satellite galaxies, intergalactic gas or dark matter (invisible material present in galaxies about which little … [is] known).” The map revealed that the Milky Way is being warped by its stars at distances more than 25 000 light years from its centre. According to the study, the distribution of the stars and their gravity is warping the galaxy’s disk to an S-like structure. It’s no small feat mapping a Milky Way that hosts as many as 400 billion stars and at least 100 billion planets. The Polish astronomers are not letting this detail hold them back from understanding our giant galaxy.