What would happen if a 200000 light years wide spiral galaxy collided with the Milky Way?

Answer 1

Likely the two galaxies would become one. Though there is some speculation in all likelyhood some stars would be lost in the process.

Incedentally in 3-5 billion years the galaxy Andromeda may collide with the milky way and it is about that size (a little smaller). In all likelyhood whan that happens our star will probably be lost fly out into the universe or into another dwarf galaxy.

Whatever happens the two galaxies would take a different course through the universe depending on how much mass the colliding galaxy has. (if it is Andromeda it is likely that we will continue on the course that we are on now)

Answer 2

If a 200,000 light-years wide spiral galaxy were to collide with the Milky Way, it would result in a major event known as a galactic merger. The gravitational forces would distort both galaxies' shapes, trigger intense star formation, and potentially cause the supermassive black holes at their centers to merge. Over time, the two galaxies would eventually merge into a single, larger galaxy.