Colliding Galaxies

[Venusian Broon]

I've been posting bits and pieces in the past few months about collisions in space, of say planets and stars, and the improbability of things hitting each other, because the universe is just so big and the space between objects is mind-blowingly vast.

But here's a lovely video explaining what sort of order of magnitude of probability of two stars colliding when the Andromeda and Milky Way galaxies collide in a few billion years.

Spoiler. It's very small! Oh and it's got maths, but don't be put off, it's pretty basic.

 

[Starbeast]

Good evening, @Venusian Broon

I've known for a long time that galaxies are so vast, that they can pass through each other without a single collision of a star, planet or moon.

However, I was unaware that our Milky Way galaxy, will collide with the Andromeda galaxy in a few billion years. Darn. I can't wait that long.

I can only imagine that spectacular view that can be seen at night, because of such an event. It would be breathtaking.

Here's a photo of a multi-galaxy collision. Astonishing.​

 

[J Riff]

I"t's not the size, it's the speed and angular momentum thing, around the ridiculous gravity of mebbe a black hole, or just a huge mass, at galactic core. Things can blow up, they can't change their distance from the center, they can't. Try it - blow up a star, none of the matter ever leaves its ring. Like a bicycle wheel. Space looks calm in pictures, but all matter is really whizzing around like crazy. Same inside colliding galaxies, no floaters allowed! )

 

[J Riff]

Truly annoying. Say Alpha Centauri blew up one day. You'd think we would get pieces of it eventually, souvenirs of an alien planet or culture but no, it would all just hang around orbiting something-or-other at thousands of MPH. Maybe some pebbles would make it here, but how would we know?