The Andromeda-Milky Way Collision

In 4 billion years, the Andromeda Galaxy will collide with the Milky Way, creating a spectacular cosmic event. Historically, Andromeda was debated as a separate galaxy, confirmed by Edwin Hubble's observations. Modern techniques have measured its velocity, predicting an inevitable collision. Simulations show the merger will form a new elliptical galaxy, with minimal impact on the solar system. Future astronomers will witness a transformed night sky, while the Sun expands into a red giant.

What role do supermassive black holes play in the merging of galaxies?

What is the likelihood of stars colliding during the merger of the Milky Way and Andromeda?

How will the night sky appear to observers on Earth after the collision?