Our Galaxy may eventually escape a collision with Andromeda in a few billion years, according to new simulations that give it a 50-50 chance of avoiding extinction.
The Milky Way and that of Andromeda are moving toward each other at a speed of 100 kilometers per second. Scientists have long thought they would be in a collision orbit in about 4.5 billion years. A scenario that does not bode well for our Universe.
Past research suggested that the Sun (and Earth with it) could be at the center of this merged, future galaxy, in a colossal black hole. It could also eject the Sun into intergalactic space.
But “announcements of the imminent end of the Milky Way appear to have been exaggerated,” according to a new study published today in the journal Nature Astronomy. The international team of astrophysicists involved in this research estimates that the probability of a collision between the two galaxies is about 50% within the next 10 billion years.
“Essentially, it’s cornucopia,” summarized Til Sawala of the University of Helsinki, the study’s lead author.
The scientists ran more than 100,000 simulations using new data collected from space telescopes.
A head-on collision between the two galaxies within the next 5 billion years is “highly unlikely,” Sawala said.
The most likely scenario is that the Milky Way Galaxy and the Andromeda Galaxy will scrape past each other without colliding immediately. In half of the simulations, dark matter will drag them into an irreversible convergence, ultimately causing a cataclysmic collision. But that won’t happen before 8 billion years have passed, since our own Sun will be long extinguished.
“It may therefore be that the Milky Way will be destroyed. But it is also possible that the Milky Way and Andromeda have been orbiting each other for tens of millions of years. We cannot yet know,” Sawala said. “The fate of the Milky Way is still unknown,” the researchers summarized.
According to Sawala, new data from Hubble and the Gaia space telescope, which just completed its mission, may allow astrophysicists to provide a definitive answer within the next decade.
But why should they bother with the question if warming will render Earth uninhabitable much sooner, in about 1 billion years? “It’s possible that we are emotionally connected” and want to know what will happen after us, Sawala explained. “I would prefer that the Milky Way not collide with Andromeda, even if it would have no effect on my own life – not even on the lives of my tricuspids,” he added.
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