In the universe, almost everything will either be swallowed by black holes, die in a star explosion, or be assimilated by other objects—that’s the process that formed Earth. Scientists have been studying the possibility of two cosmic monsters colliding, but scientists cannot observe this regularly. On the other hand, theories about the Milky Way’s future are confirmed due to observed trajectories, and what’s about to happen will cause a major impact on humanity’s legacy in the universe and leave no signs of what we’ve lived so far.
The Milky Way is one of billions of galaxies in the universe
The Milky Way is just one of hundreds of billions of galaxies in the universe, and it’s far from being one of the biggest. Most galaxies are not culturally known, but the Andromeda Galaxy is, and it has been referenced through a variety of studies, movies, and television shows—it is in the imagination of those who dream about other galaxies.
The Andromeda Galaxy is considerably bigger than our stellar system. The Milky Way has a diameter of 100,000 light-years, while Andromeda’s total diameter is estimated to be 220,000 light-years. For years, the galaxies have been on a collision course, which will create a super-galaxy named ‘Milkomeda’, but this might be happening later than expected.
The end will happen later than expected
After running 100,000 simulations using new data collected by the Hubble and Gaia space telescopes, researchers found there is about a 50% chance of Andromeda and the Milky Way colliding in the next 10 billion years. After the calculations were made, the scientists estimated a 2% chance of the catastrophic event happening within only 4 to 5 billion years.
A merger between the two galaxies would destroy them both, and a new one would be born. The lead author of the research, Dr. Till Sawala, an astronomer at the University of Helsinki, and his team—which includes researchers at Durham University in England—stated that a collision between galaxies creates ‘cosmic fireworks’, a result of the gas that’s attracted to the center of the merging point feeding the central black hole from the other galaxy, creating an enormous amount of radiation.
A third galaxy is involved in the delay of the merging process
One of the galaxies close to the Milky Way is the Large Magellanic Cloud (LMC), a dwarf galaxy containing a few billion stars. The LMC orbits our galaxy. Meanwhile, another galaxy called M33 is a satellite of Andromeda. Both LMC and M33 are supporting actors in our local group of galaxies, but they might be the heroes we never asked for.
Both star systems influence the collision with their gravitational pull—the LMC pulls the Milky Way off the orbital plane and away from Andromeda, which changes the Milky Way’s motion enough to make the merger less likely. Dr. Till Sawala explained the team ran thousands of simulations, which in over half of them predict the two galaxies fly past each other and eventually merge in the far future.
What’s next after the big merger?
Dr. Sawala explained that the collision between the Milky Way and the Andromeda Galaxy would most likely involve a strong starburst, during which many new stars would form. Events like this are followed by a period of intense radiation caused by the explosion of young stars and active supermassive black holes, which eventually shuts down the star formation completely. In a matter of billions of years, any traces of both galaxies will be erased from the universe, leaving only a ‘new’, super-galaxy.
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