Milky Way last major collision

The Barbarian said:

The cool thing is, it is highly unlikey that any stars will collide with each other, because they are so widely separated in space. Gravitational effects, however, will be catastrophic, slinging stars everywhere.

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Agreed. I made the analogy of two flocks of birds flying past each other.


This scientist explains the probability of two stars colliding in a galactic collision (duration = 14 min):

Summary:
The video discusses the phenomenon of galaxy collisions or mergers, explaining that they are not uncommon events in the universe. Most galaxies are expected to undergo a merger with another galaxy at some point in their lifetime. These mergers can vary in intensity, ranging from minor mergers involving smaller galaxies to major mergers where two similar-sized galaxies collide. In major mergers, the gravitational forces involved are significant, leading to galaxies being torn apart and transformed from beautiful spiral structures into blobby shapes.

As an example, the speaker mentions the Milky Way and its surrounding smaller galaxies such as the Sagittarius Stream, which consists of stars from a minor merged galaxy that is currently orbiting the Milky Way. Another notable example is the Andromeda Galaxy, which is heading towards the Milky Way due to its blue shift and is predicted to collide with our galaxy in approximately two billion years, creating what is known as the Milkomeda galaxy.

To better understand galaxy mergers, scientists use computational simulations to recreate and study the processes involved. Astronomers compare the results of these simulations to actual observations of galaxy mergers in the universe. One interesting aspect discussed in the transcript involves calculating the probability of two stars colliding during a galaxy merger. Although there are trillions of stars in galaxies, the large amount of space between them significantly reduces the likelihood of a collision occurring. Using calculations based on various simplifying assumptions, the speaker estimates the probability of a star in the Milky Way colliding with any single star in the Andromeda Galaxy to be around 1 in a sextillion (approximately 1 x 10^-21). This extremely small probability demonstrates why such stellar collisions are indeed rare events within galaxies.