About 10 million years ago, a spectacular astronomical collision event took place in our Milky Way. A small galaxy shaped like a sausage collided with the Milky Way, thus shaping the characteristic structure of the Milky Way – the central star bar. This discovery not only changes our understanding of the formation of the Milky Way, but also provides new insights into the history of other galaxies.
Through analysis of recent observational data, scientists speculate that the Milky Way’s star bars may be about 10 million years old and occurred with the so-called “Galileo-Enceladus-sausage” (GES) merger event. The time coincides with that. In order to explore whether this merger may form star bars, the researchers used computers to simulate a scenario similar to the GES galaxy impacting the Milky Way, and then observed the motion of the stars in the simulation under the influence of “gravity”. It was found that the stars quickly formed a star bar, indicating that this merger event may have led to the formation of the Milky Way star bar.
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This research provides important clues to our understanding of the origin and evolution of the Milky Way, and has a profound impact on understanding our planet and its place in the Milky Way. Scientists believe that our sun may have even been born in a completely different part of the galaxy under the influence of the star bars, and was eventually attracted by its gravitational influence, migrating to its current location.
Observe stars forming star bars under the influence of “gravity” over time
NGC 613 is a galaxy located south of the constellation Sculptor, about 67 million light-years away from Earth. In this image captured by the NASA/ESA Hubble Space Telescope, NGC 613 is an example of a striped spiral galaxy with a distinct central star bar and long spiral arms surrounding the core. Like our Milky Way, about two-thirds of spiral galaxies contain such stars. (Photo/NASA) Advertisement (Please continue reading this article)
Nearly two-thirds of spiral galaxies have star bars, which play a crucial role in the mystery of how stars, gas and energy move around a galaxy because of their gravitational influence. However, astronomers don’t fully understand how they form. While we can’t travel back in time to witness the Milky Way’s origins, astronomers can study nearby stars of different ages in detail, giving us clues to the past. “Observational clues exist in starlight, just as fossils tell us about Earth’s history,” the team explains. “In particular, the positions, movements and chemical composition of stars in galaxies tell the story of our universe’s past.”
Our galaxy also plays an important role on the tiny planet we live on. In the Milky Way, we live far away from the stars, but we are not outside their influence. As the star bar moves around the stars, it may also move our sun – where you live in the galaxy has a huge impact on how comfortable the planet you live on is. The scientists added that the Sun may have “been born in a completely different part of the Milky Way, with the gravitational influence of the star bars moving it to its current position.”
The research is expected to be published in the latest issue of Monthly Notices of the Royal Astronomical Society.
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First picture source: NASA cc By4.0
Image source: NASA cc By4.0
Reference papers:
1.Did the Gaia Enceladus/Sausage merger form the Milky Way’s bar?arXiv
Further reading:
