For more than a decade, researchers have assumed a high probability that our Milky Way galaxy will collide with the neighboring Andromeda galaxy in about 5 billion years. The collision would merge these two galaxies into one (with the very creative name “Milky Way”) – but new research shows that this is less likely than previously thought.
By integrating new data from the Gaia and Hubble telescopes, an international team of researchers has modeled the movement of our galaxy over the next 10 billion years. The computer model also uses new estimates of the masses of other galaxies in the Local Group, a galaxy group that contains the Milky Way and Andromeda, among others. Ultimately, the simulation shows that there is only about a 50% chance that these two galaxies will collide within the next 10 billion years, confirming similar results from previous studies.
“Here we consider the latest and most accurate observations from the Gaia and Hubble space telescopes, as well as the latest consensus mass estimates, to derive possible future scenarios and identify the main sources of uncertainty in the evolution of the Local Group over the next 10 billion years,” the researchers, including experts from the University of Helsinki and Durham University, write in the study. “We found that the uncertainty in the present positions, motions, and masses of all the galaxies leaves room for radically different outcomes and a probability close to 50% that the merger of the Milky Way and Andromeda will not occur within the next 10 billion years.”
Just as planets influence each other through gravity, galaxies also influence their galactic neighbors. Specifically, Andromeda, the Triangulation galaxy, and the Large Magellanic Cloud (a galaxy orbiting the Milky Way) all influence the path of the Milky Way. According to the researchers, previous analyses that calculated higher odds probably did not take into account the gravitational pull of the Large Magellanic Cloud. “The orbit of the Large Magellanic Cloud runs perpendicular to the orbit of the Milky Way-Andromeda and makes their merger less likely,” they explain.
Their modeling also took into account uncertainties, another factor that could reduce the probability. Nevertheless, the team emphasizes the fact that even with the latest information, there are still a number of unknowns that make it difficult to determine exactly how the Milky Way and Andromeda will move, although more data from the Gaia telescope could continue to refine their predictions.
While Milky Way may never come to fruition, researchers have identified another highly likely collision that will almost certainly occur within the next two billion years: the merger of the Milky Way with the Large Magellanic Cloud (I don’t even want to know what they’ll name the resulting galaxy).
