Astronomers using data from NASA’s Hubble Space Telescope and the European Space Agency’s Gaia space telescope have re-examined the long-held prediction of a collision between the Milky Way and Andromeda galaxies. The new study suggests that a head-on collision is far less inevitable than previously thought, with only a 50-50 chance of occurring within the next 10 billion years.
Researchers found that there are approximately half of the simulations where the two main galaxies fly past each other separated by around half a million light-years or less, but continue their orbital waltz for a very long time. In most cases, the galaxies don’t even come close enough for dynamical friction to work effectively.
The study also considered the effects of Andromeda’s large satellite galaxy and the Milky Way’s own satellite galaxy on the potential collision. While one effect was found to pull the Milky Way closer to Andromeda, the other effect pulled it away from a head-on collision.
“It’s somewhat ironic that, despite the addition of more precise Hubble data taken in recent years, we are now less certain about the outcome of a potential collision,” said Till Sawala, lead author of the study. “The only way to get to a new prediction about the eventual fate of the Milky Way will be with even better data.”
The Hubble Space Telescope has made groundbreaking discoveries over its three-decade operation and continues to shape our understanding of the universe. However, the new findings leave more questions than answers, highlighting the uncertainty involved in predicting the long-term future of galaxy interactions.
Source: https://science.nasa.gov/missions/hubble/apocalypse-when-hubble-casts-doubt-on-certainty-of-galactic-collision