Ah, the Milky Way, our glittering home in the cosmos. Seen in an unencumbered night sky, far from the glare of city lights, it seems magnificent and eternal in its enormity. Nothing could shift this ancient web of stars, nothing could disturb its transcendent stoicism.
Except, that is, another galaxy. Galaxies orbit millions of light-years apart, but gravity, the immutable magnet of the cosmos, can pull them together, producing spectacular collisions that reshuffle stars. According to the leading theory, the Milky Way will collide with one of its closest neighbors, Andromeda, sometime between 6 billion and 8 billion years from now.
But the Milky Way may face another galactic threat before that, from a different neighbor. A new study predicts our galaxy will collide with a galaxy called the Large Magellanic Cloud between 1 billion and 4 billion years from now.
This is a rather surprising change in schedule, considering that the Large Magellanic Cloud, which is close enough to be seen with the naked eye, is currently moving away from the Milky Way. What gives?
Marius Cautun, an astrophysicist at Durham University’s Institute for Computational Cosmology, says that recent observations of the Large Magellanic Cloud have revealed that the galaxy has more mass than previously thought. Cautun and his fellow researchers decided to run computer simulations that took this new factor into account and fast-forwarded the conditions of our cosmic neighborhood. They tested multiple scenarios, making adjustments in mass, velocity, and other measures. In the end, the simulations predicted that in several hundred million years, the Large Magellanic Cloud will turn around and head straight for the center of the Milky Way.