The shape of Milky Way

Certainly everyone reading this article has an accurate memory of their physical appearance, thanks to mirrors. However, “self-observing” without the use of the optical tool mentioned (or phenomena such as reflection) becomes an impossible feat. However, science is so surprising that an achievement equivalent to the situation described above becomes possible.

At the beginning of August 2019, a group of researchers published a study in the journal Science, in which is shown that our galaxy has a different structure than the one previously thought (the Milky Way disc shape was previously theorized to be. approximately flat), with the disc being much more contorted, resulting in a potato-like shape. Studying the shape of the Milky Way is a challenging task for scientists, and this is because we live in such galaxy and therefore that would be the equivalent of “self-observing”. Other galaxies can be studied in a much simpler way, given the possibility of direct observation. In order to make possible the “visualization” of our galaxy, astronomers make various observations of different celestial bodies, so that they can accurately mark their relative distance, thus obtaining an appropriate spatial reference for mapping the region studied. In astronomy, among the objects most commonly used for distance measurement are: supernovae, red giants, variable stars, among other objects, whose luminosity characteristics are convenient to the determination of distances.

The scientists made a series of observations of Cepheid variable stars (2341 were observed) in the outermost regions of the Milky Way, thus they were able to calculate, with 5% accuracy (which is considered high precision), the distance to such stars and also obtained the distribution pattern of such stars. The studies carried out allowed the creation of an advanced 3D model, which allows the visualization of the shape of the Milky Way. Although we do not know what is the real cause of the twisting of our galaxy's disc, there are possible hypotheses which point to different reasons such as: interactions with intergalactic gas, satellite galaxies or dark matter.

Photo of the model of the Milky Way shape following recent studies.