By: The Science Times
The Milky Way is thought to have developed from a spinning cloud of gas 13.6 billion years ago. It now houses over 100 billion stars and provides us a home. The results of a study on the galactic disk's outer regions were published in Monthly Notices of the Royal Astronomical Society. The study team has demonstrated that certain regions of the Milky Way's outer disc vibrate; the ripples caused by the dwarf galaxy may be observed in the constellation Sagittarius. In addition, one may observe the stars swaying "up and down at varying speeds." According to one theory, the Milky Way galaxy experienced waves when the dwarf galaxy Sagittarius passed it.
Sagittarius' orbit around the Milky Way was revealed by measuring the strength of the ripples in various regions of the cosmic disc. According to Paul McMillan, an astronomer at Lund Observatory who also led this study, "At the moment, Sagittarius is slowly being torn apart, but 1-2 billion years ago it was significantly larger, probably around 20 percent of the mass of the Milky Way's disk."
The Gaia telescope, which deserves credit for leading to this finding, has been in operation since 2013 to track the motion of two billion stars as they move across the sky. Overall, this finding improves our knowledge of the Milky Way's evolution.
References:
Lund University. "Mysterious ripples in the Milky Way were caused by a passing dwarf galaxy." ScienceDaily. ScienceDaily, 23 September 2022. <www.sciencedaily.com/releases/2022/09/220923121707.htm>.
Paul J McMillan, Jonathan Petersson, Thor Tepper-Garcia, Joss Bland-Hawthorn, Teresa Antoja, Laurent Chemin, Francesca Figueras, Shourya Khanna, Georges Kordopatis, Pau Ramos, Merce Romero-Gómez, George Seabroke. The disturbed outer Milky Way disc. Monthly Notices of the Royal Astronomical Society, 2022; DOI: 10.1093/mnras/stac2571
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