Milky Way May Hide Coincidentally Scientists Once Think

Our Milky Way probably won’t travel to the cosmic quick program that astronomers have predicted for decades. New research shows that over the next 10 billion years, the Milky Way has only 50-50 chances to collide with the neighboring Andromeda galaxy, a discovery that subverts one of the most widely accepted predictions in astronomy.

For more than a century, scientists have known Andromeda to race towards us at 250,000 miles per hour. This discovery gave people a confident prediction of the inevitable galaxy crushing of about 4.5 billion years, a situation that became textbook knowledge and attracted public imagination.

However, an international team from the University of Helsinki, Durham and Toulouse performed 100,000 computer simulations using the most accurate measurements obtained from NASA’s Hubble and the European Space Agency’s Gaia Space Telescope. Their results in Natural Astronomy tell a completely different story.

No one considers the factors that change the game

“Our very different results are mainly due to two factors,” explains Savala of the University of Helsinki. “First of all, although some of the early works focus on the interaction between the Milky Way, Andromeda and the triangle galaxy, we also include the effects of the Milky Way’s largest satellite, the Great Magellanic Cloud.”

Large Magellan clouds are visible in the southern sky, only 15% of the mass of our Milky Way. However, its gravitational influence is perpendicular to the Milky Way-Andromeda orbit, thus creating enough interference to significantly reduce the chance of merger. Previous research largely overlooked this cosmic wildcard.

The second breakthrough involves the accounting of measurement uncertainty masked by early research. Even with the most complex instruments today, astronomers face obvious false margins when measuring distances, mass, and movements of Milky Way over millions of light-years.

When accuracy reveals uncertainty

“Even if we benefit from the most precise measurements, we now find a lot of uncertainty in the results,” Sawala noted.

The research team found that small changes in properties measured by any galaxy can flip the entire universe script. The appropriate motion measurements of Andromeda are particularly critical – the uncertainty range of ±2σ includes the above values ​​above the merge probability, as well as other opportunities that indicate near-zero collisions.

What does this mean for the Galaxy Watcher? If a merger does occur, it will be much later than previously expected – 700 million years from now, rather than the 4.5 billion years usually cited.

Key research results:

• Only 54% of simulations resulted in the merger of the Milky Way within 10 billion years
• There is only 2% chance of direct collisions within 400 million years
• Large Magellan Cloud reduces merger probability by generating vertical gravity
• M33 (triangle galaxy) increases the possibility of merge when increasing calculation

The team’s analysis reveals something compelling about the dynamics of the Milky Way: The orbits are either spiral inwardly due to dynamic friction, merged, or kept distances too large to take effect, so the galaxy can continue its cosmic dance indefinitely.

Challenging scientific orthodoxy

“The upcoming collision between our galaxy and Andromeda is a famous result, found anywhere from textbooks to children’s literature,” commented Jehanne Delhomelle of the University of Toulouse, who worked as an exchange student in Helsinki. “This is part of the beauty of the scientific process, and even widely accepted results can always be challenged and can be overturned.”

The researchers stressed that they found no errors in previous calculations. When they copied the early assumptions, they recovered the same results. Instead, they expanded the analysis to explore greater possibilities.

Their complex modeling shows that the uncertainty of current location, action, and group leave room for distinct results. The study used each galaxy parameter to a spherical halo, which was followed by established cosmological models and then calculated dynamic friction in thousands of orbital scenarios using analytical formalism.

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Uncertainty may not last forever. The upcoming Gaia data release is expected to provide more accurate correct motion measurements, especially for Andromeda, whose movement affects the probability of collision at most.

“Currently, we are using improved physics models to prepare the next set of simulations,” added Jenni Häkkinen of the University of Helsinki. “By combining them with updated observational data, we aim to make the most accurate predictions of the fate of the Milky Way in the coming years.”

Peter Johansson of the University of Helsinki’s bet was: “Although the Milky Way has experienced dozens of secondary mergers in its lifetime, its last major merger occurred 10 billion years ago. The potential Milky Way merger is a potential merger for Andromeda, a rare and transformative event in the Milky Way, so it’s important for the model.”

Whether our galaxy is facing a cosmic collision or continuing a lonely journey through space, one thing is still certain: the universe is still surprising and even challenges our most confident predictions. As this study shows, sometimes the most precise measurements suggest that the elegant complexity of cosmic uncertainty itself is uncertain.

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