Recent study raises the chance of a merger between the Milky Way and Andromeda to 90% in billions of years

Astronomers have updated projections about the fate of Via Láctea and the Andrômeda galaxy based on more precise measurements of stellar motions. The Andrômeda galaxy, located about 2.5 million light-years away, approaches Via Láctea at a relative speed of approximately 110 kilometers per second. A study published in 2026 incorporated refined data from the Gaia satellite and indicated that the probability of merger between the two spiral galaxies reaches 90% in the next 10 billion years.

The simulations considered the gravitational influences of other members of Grupo Local, such as the galaxy of Triângulo (M33) and the Grande Nuvem of Magalhães. Previous Resultados, from 2025, pointed to a chance of just 50% of collision in the same time interval. The new modeling with 10 thousand random trajectories significantly increased confidence in the occurrence of the cosmic event.

• Dark matter halos of the two galaxies already partially overlap
• Galactic nuclei maintain a direct approach trajectory
• Individual stars have a low chance of physical collision due to interstellar space
• Resulting merger will form a giant elliptical galaxy known as Milkomeda

Observational data refines galaxy merger scenario

Measurements of the proper motions of stars in Andrômeda, obtained with high precision by Gaia, made it possible to reduce uncertainties in the positions, velocities and masses of the galaxies involved. Cada dark matter halo of the two structures contains about a trillion solar masses, which accelerates the process of gravitational interaction. The median projected time for complete fusion was 6.5 billion years, with a margin of error of plus or minus 1.3 to 1.5 billion years.

Astronomers highlight that Sol, currently around 4.6 billion years old, will still be in an active phase when the first strong interactions occur. Simulações show that Sistema Solar can be moved to new orbits within the resulting galaxy without planets suffering direct impacts from stars. The event represents the last major merger in the local history of Grupo from Galáxias before the accelerated expansion of the universe isolates remaining structures.

External influences change trajectories in Grupo Local

The inclusion of the M33 galaxy in the simulations increased the probability of merger by reinforcing indirect gravitational attractions. On the other hand, the perpendicular orbit of Grande Nuvem from Magalhães tends to slightly reduce this chance in some scenarios. Mesmo with these variables, the fraction of trajectories leading to merger within 10 billion years reached 90% in the most recent analysis.

Researchers analyzed one hundred representative trajectories in face-on and edge-on projections to visualize the dynamic evolution. Orbit Linhas highlight how the centers of galaxies gradually approach each other, with curves indicating minimum separation over time. Essas computational modeling incorporates updated mass and motion data for greater realism.

The merger will not occur abruptly, but through successive passages that will distort the spiral structures over billions of years. Durante the process, bursts of star formation can occur due to the compression of interstellar gas clouds. The end result will be a larger elliptical galaxy, with stellar and dark matter reserves approximately double that of today’s Via Láctea.

Implications for future observations and instrumental precision

Further improvements in proper motion measurements, with uncertainties below 2 microarcoseconds per year, will be needed to confirm definitive trajectory details. Advanced Telescópios can detect electromagnetic signals or other signs of activity in Andrômeda star systems that help map the event in advance. Light from such signals would take 2.5 million years to reach Terra, a range comparable to the human presence on the planet.

Astronomers continue to monitor the night sky for indirect evidence of interactions already underway between outer halos. The current overlap of these dark matter halos marks the subtle beginning of a process that will extend across cosmic timescales. The precise Observações of Gaia represents a significant advance in understanding the dynamics of Grupo Local.

Evolution of the night sky in billions of years

As the galaxies approach, Andrômeda’s disk will occupy an increasingly larger portion of Terra’s visible sky. Stellar Padrões will gradually shift as stars from both galaxies mix into new orbital configurations. Sol and Sistema Solar will remain intact, although they may migrate to different regions within the new galactic structure.

After the complete merger, Milkomeda will have a more spheroidal and homogeneous shape, typical of giant elliptical galaxies. In about 100 billion years, the accelerating expansion of the universe will leave this galaxy isolated in an increasingly empty space. Hipervelocidade of stars ejected during the process could serve as tracers for future studies on cosmic expansion.

Technical details of recent simulations

The 2026 study used ten thousand full simulations that included the four main massive galaxies of Grupo Local. Gráficos of separation between centers show curves with a clear median around 6.5 billion years for the merger cases. White Símbolos marks specific encounter times on individual trajectories, while the most likely curve highlights the dominant path.

These computational modeling validate the restoration of the classical view of inevitable merger at high probability. Previous Dados of 2025, based on combinations of Hubble and Gaia, had introduced greater uncertainty due to external variables. The current analysis balances these influences and reinforces the expectation of direct interaction.

The current distance of 2.5 million light years still allows Andrômeda to be the most distant object visible to the naked eye on clear nights. Sua continuous approximation occurs imperceptibly on human scales, but accumulates over billions of years to produce profound structural transformations. Additional Pesquisas with next-generation instruments should further refine these projections.