Milky Way May Avoid Collision with Andromeda Galaxy

The long-held belief that the Milky Way galaxy would inevitably collide with the Andromeda galaxy has come into question, thanks to new findings from an international team of researchers. Recent computer simulations indicate that a nearby star cloud could alter the course of the Milky Way, potentially allowing it to avoid a catastrophic collision.

For decades, astronomers have predicted that in approximately five billion years, the Milky Way and Andromeda would collide. However, the latest simulations suggest a different outcome. The gravitational influence of the Large Magellanic Cloud, a satellite galaxy of the Milky Way, may help steer both galaxies away from a collision. According to the research published in the journal Nature Astronomy, only about two percent of the 100,000 simulations conducted resulted in a direct collision.

Currently, the Milky Way and Andromeda are moving towards each other at a speed of around 100 kilometers per second, with their current distance estimated at approximately 2.5 million light-years. Over billions of years, this distance will decrease significantly, leading to potential interactions.

Researchers emphasize that if a collision were to occur, the two spiral galaxies would merge into a single elliptical galaxy. However, the new calculations, based on the most precise measurements obtained from the Hubble and Gaia space telescopes, take into account not only the Milky Way and Andromeda but also the influence of the Large Magellanic Cloud and the Triangulum Galaxy (M33), which is located about 2.7 million light-years away.

While the presence of M33 increases the likelihood of a collision, the gravitational pull of the Large Magellanic Cloud acts in the opposite direction, making a collision unlikely within the next five billion years. The impact of the Large Magellanic Cloud is nearly perpendicular to the movement of both galaxies, creating a scenario where they may take a diverging path.

In nearly half of the simulations, close encounters between the two galaxies do occur, but only a small fraction ultimately results in a collision. In cases where close approaches happen, the galaxies lose kinetic energy, which slows them down and leads them to orbit each other on increasingly tighter paths. This scenario could eventually culminate in a merger, albeit in a timeframe of eight to ten billion years.

The research team expresses hope for even more refined data from the Gaia mission, which has been accurately measuring the positions and movements of billions of celestial objects since its launch in 2014, situated 1.5 million kilometers from Earth.