New research indicates that the most recent major collision in our galaxy occurred billions of years later than previously believed.
Using data from the Gaia spacecraft, researchers found that the “For the wrinkles of stars to be as obvious as they appear in Gaia data, they must have joined us no less than three billion years ago – at least five billion years later than was previously thought,” said Newberg, Donlon’s thesis adviser at Rensselaer. “New wrinkles of stars form each time the stars swing back and forth through the center of the Milky Way. If they’d joined us eight billion years ago, there would be so many wrinkles right next to each other that we would no longer see them as separate features.” The collision is thought to have resulted in a large number of stars with unusual orbits. Previously, scientists dated it at between eight and 11 billion years ago in a collision called the Gaia-Sausage-Enceladus (GSE) merger. Rather, Newberg and Donlon’s findings indicate that the stars may have resulted from the Virgo Radial Merger, which crashed through the center of the Milky Way less than three billion years ago. “Gaia is a hugely productive mission that’s transforming our view of the cosmos,” says Timo Prusti, Ph.D., Project Scientist for Gaia at the European Space Agency. “Results like this are made possible due to incredible teamwork and collaboration between a huge number of scientists and engineers across Europe and beyond.” “Through this study, Doctors Newberg and Donlon have made a startling discovery about the history of the Milky Way galaxy,” said Curt Breneman, Ph.D., dean of the School of Science. “Gaia data is offering unprecedented opportunities to better understand our universe, and I am thrilled that Rensselaer researchers were able to harness the power of this incredibly detailed new data.” Reference: “The debris of the ‘last major merger’ is dynamically young” by Thomas Donlon, Heidi Jo Newberg, Robyn Sanderson, Emily Bregou, Danny Horta, Arpit Arora and Nondh Panithanpaisal, 16 May 2024, Monthly Notices of the Royal Astronomical Society. Newberg and Donlon were joined in research by Robyn Sanderson, Ph.D., of the 
Implications of the New Findings
DOI: 10.1093/mnras/stae1264
Discussion about this post