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A new study published in Nature Astronomy reveals that our galaxy is not exactly a flat disk as it was thought until now, because it has deformed edges.
As we live in the Milky Way, we can not observe. the shape of our galaxy at a distance, as we do with other galaxies, so we have to study similar galaxies to estimate our actual appearance. Andromeda, for example, is larger than the Milky Way, but both are very large, both are spiral galaxies and both are about the same age.
But, according to the new study, astrophysicists have discovered that the more the Milky Way disk becomes distracted from the galactic center, the more it is twisted and twisted. Thus, the galactic plane of our galaxy is not a straight line, but rather an elongated letter in "S". And this conclusion was made possible by new measurements of star distances in the outer regions of the galaxy.
These stars are of the Cepheid type, giant or yellow supergiants quite mbadive and shiny , which pulses at a precise frequency and thus allow astronomers to calculate their absolute magnitude, which then makes it possible to calculate the distances of these stars which are part of the pulsating variable clbad.
Scientists have used infrared radiation to measure because it can penetrate the clouds of gas and dust that separate us from the stars. in more accurate data than the observation of the optical spectrum (because the perception of the brightness of stars can be cluttered by clouds of gas and dust). According to the astrophysicist Richard de Grijs of Macquarie University, the team used a new catalog of infrared observations obtained with the WISE space observatory, which allowed to determine the distances Cepheids with uncertainties of less than 3 to 5%.
Then, combining these observations with their apparent locations in the sky, the team created a three-dimensional map of the Milky Way, noting that the model was not exactly that of a flat disk. It is not uncommon to find spiral galaxies with deformed edges, but in the case of the Milky Way in particular, the discovery is interesting because these deformed edges include stars. According to Grijs, "the precession of the disc seems to imply that the mbadive internal disk of the Milky Way could force the outer disk to follow its rotation, but the rotation of the outer disk is left behind, causing a twist".
The study gives us a better understanding of the three-dimensional and dynamic structure of our galaxy and will help scientists better understand the relationship between the Milky Way and its satellite galaxies, including the Great Magellanic Cloud, which is expected to enter in collision with our galaxy. in the 2 billion years – even before the collision with the Andromeda galaxy, which should occur only in 4 billion years.
Source: Science Alert
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