100,000 laptop simulations reveal Milky Manner’s destiny—and it won’t be what we thought.
It has been textbook information for over a century that our Milky Manner galaxy is doomed to collide with one other massive spiral galaxy, Andromeda, within the subsequent 5 billion years and merge into one even larger galaxy. However a recent evaluation printed within the journal Nature Astronomy is casting that longstanding narrative in a extra unsure gentle. The authors conclude that the chance of this collision and merger is nearer to the chances of a coin flip, with a roughly 50 p.c chance that the 2 galaxies will keep away from such an occasion in the course of the subsequent 10 billion years.
Each the Milky Manner and the Andromeda galaxies (M31) are a part of what’s often called the Native Group (LG), which additionally hosts different smaller galaxies (some not but found) in addition to darkish matter (per the prevailing customary cosmological mannequin). Each have already got remnants of previous mergers and interactions with different galaxies, in response to the authors.
“Predicting future mergers requires information in regards to the current coordinates, velocities, and much of the programs partaking within the interplay,” the authors wrote. That entails not simply the gravitational pressure between them but in addition dynamical friction. It is the latter that dominates when galaxies are headed towards a merger, because it causes galactic orbits to decay.
This newest evaluation is the results of combining knowledge from the Hubble Area Telescope and the European Area Company’s (ESA) Gaia house telescope to carry out 100,000 Monte Carlo laptop simulations, considering not simply the Milky Manner and Andromeda however the full LG system. These simulations yielded a really completely different prediction: There’s roughly a 50/50 likelihood of the galaxies colliding throughout the subsequent 10 billion years. There’s nonetheless a 2 p.c likelihood that they may collide within the subsequent 4 to five billion years. “Based mostly on the most effective out there knowledge, the destiny of our galaxy remains to be fully open,” the authors concluded.
