Till Sawala: Apocalypse When? No certainty of a Milky Way - Andromeda merger

Tuesday 17 Feb 2026, 13:15 → 14:00 Europe/Stockholm

FB52 (AlbaNova Main Building)

It was commonly believed that our own Milky Way is on a collision course with the neighbouring Andromeda galaxy. As a result of their merger, predicted to occur in around five billion years, the two large spiral galaxies that define the present Local Group would cease to exist, and a new, elliptical galaxy would disappear. I will discuss the observational data and models that led to this prediction, but then show that, based on observations by the Gaia and Hubble space telescopes along with recent consensus mass estimates for the four most massive Local Group galaxies, there are in fact several possible future scenarios, and no certainty of a Milky Way - Andromeda merger within the next 10 billion years. I will also preview ongoing and future work needed to address existing simplifications and additional uncertainties, with the aim of building a more complete understanding of the Local Group's future evolution.

Bio:  Dr. Till Sawala is a docent in astrophysics at Helsinki University. His work primarily focuses on the Local Group and the Local Universe, which he explores using a variety of computational methods. While much of astrophysics and cosmology looks towards the past for an understanding how the fundamental forces of the universe have shaped its evolution, he is also curious to apply the same methods towards predicting the (very far) future.

At the OKC:  Monday afternoon through Wednesday, CoPS corridor A5.