A new study suggests that the long-predicted collision between the Milky Way and Andromeda galaxies may not be inevitable. While past research estimated the crash would occur in 4-4.5 billion years, updated simulations incorporating fresh variables indicate that the likelihood of a merger is less than 2% within the next 5 billion years and about 50% within the next 10 billion years.
Galactic Motion & Uncertainty
The Milky Way and Andromeda are currently 2.5 million light-years apart, moving toward each other at 250,000 miles per hour (400,000 km/h). However, the study, published in Nature Astronomy, suggests that other nearby galaxies, including the Triangulum Galaxy (M33) and the Large Magellanic Cloud, significantly influence their trajectories. The inclusion of the Large Magellanic Cloud in the model reduces the likelihood of a merger.
Potential Outcomes
If a merger does occur, it is more likely to happen 7-8 billion years from now, forming a new elliptical galaxy. However, the study emphasizes that current data does not allow for a precise prediction. Meanwhile, a collision between the Milky Way and the Large Magellanic Cloud is almost certain within the next 2 billion years, long before any potential interaction with Andromeda.
Impact on Earth & the Solar System
Regardless of the galaxies' fate, Earth is expected to become uninhabitable in about 1 billion years, as the Sun’s increasing heat will boil away the oceans. The Milky Way’s supermassive black hole (Sagittarius A)* is significantly smaller than Andromeda’s, which could lead to a black hole merger if the galaxies eventually collide.
This study challenges long-held assumptions about the Milky Way’s future, highlighting the complex gravitational interactions that shape galactic evolution.
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