[Blikkentrekker]

Why would stars hit each other during galactic collisions when stars inside of a single galaxy already almost never hit each other? Apparently reading it here of all the stars in the galaxy, a stellar collision only happens once every 10 000 years.

Interestingly enough, when galaxies collide, the supermassive black holes at their centres do typically merge as their gravity is strong enough to attract each other.

It's by the way not particularly unlikely for stars to pass through other solar systems. Apparently about 70 000 years ago a binary star system flew through the Oort Cloud.

[aetherspawn]

Thinking of the scales involved, even at the speed of light probably two masses couldn’t pull each other fast enough to collide (if you are colliding the two galaxies at the fastest manifestible speed which is the speed of the light).

That’s hand wavy because if you’re imagining like grabbing the two galaxies and smashing them together… that’s like giga levels of magnitude faster dynamics than the speed of light, ha!

You’d have to like put the galaxies on top of each other and leave them there, probably for years, for gravity to get everything moving quickly enough (and then for the speed of light to even bridge the distance!) before really anything would happen. I think.

Engineer but not a physicist.

[Ekaros]

An other aspect is that orbital mechanics are weird/chaotic. Specially when you get masses that are similar scale. Like why hasn't moon hit earth yet?

So with two galaxies colliding I would not expect the stars to hit each other as result of collision. But as result of interactions when speeds increase.