Contact with a Dwarf
Until recently, scientists believed that the Milky Way would collide with Andromeda, which is approximately 2.5 billion light-years away. This collision is expected to occur in about 5 billion years, so there is still plenty of time.
However, Andromeda is not the only galaxy heading toward the Milky Way. Much closer is the Large Magellanic Cloud, located just 160,000 light-years away—essentially a cosmic neighbor.
Unlike Andromeda, which is much larger than the Milky Way, the Large Magellanic Cloud is quite small. It has a diameter of around 14,000 light-years and contains approximately 10 billion stars. While this might sound massive, even medium-sized galaxies are far larger.
Previously, scientists assumed that the Large Magellanic Cloud lacked sufficient mass to be strongly gravitationally attracted to the Milky Way. However, recent observations have revealed otherwise. The key factor is a surrounding cloud of dark matter, which is roughly twice as massive as previous estimates suggested.
Because of this, a collision with the Large Magellanic Cloud is now considered inevitable. It is expected to occur within two billion years.
What Are the Risks?
Computer simulations suggest only a 7% chance that the Large Magellanic Cloud will not collide with the Milky Way before Andromeda does.
Although it is a relatively small galaxy, the impact on the Milky Way could be significant. The collision will likely involve hundreds of millions of stars and planets. Many star systems will cease to exist, while others may be violently ejected from their orbits, becoming wandering celestial objects.
This event could also mean the end for Earth. If a large enough object collides with our planet, it could be catastrophic. Even if Earth were merely knocked out of its orbit, it would become uninhabitable, eventually turning into a frozen, lifeless rock.