>If the Milky Way and Andromeda are to collide and merge, the researchers found that it would most likely happen in 7 to 8 billion years’ time, significantly later than previously predicted.
Aah damn well let me check my calendar for what I'll being doing in 7 billion years instead of 4...
didgetmaster · 2h ago
When simulating an actual merger with the two galaxies; any estimates on the number of stars that might collide?
400+ billion stars per galaxy might make each one seem 'dense' but the distance between stars is enormous.
I have heard that it might be possible for one galaxy to pass through another without any stars colliding with each other. I don't have any idea if that is actually true.
> Although the galaxies will plow into each other, stars inside each galaxy are so far apart that they will not collide with other stars during the encounter. However, the stars will be thrown into different orbits around the new galactic center. Simulations show that our solar system will probably be tossed much farther from the galactic core than it is today.
raverbashing · 1h ago
Very low probability times massive number of stars: yes I think there will be a non-zero number of actual collisions
bruce511 · 21m ago
You are confusing one big number with another big number, and treating them as the same.
Yes there are a lot of stars. It's a big number. But there's a lot of space. That's a number that's in a whole different league.
For example, the whole solar system is about 2 light-day diameter. But it's 4 light years from the nearest star in any direction. Empty space is thus many orders of magnitude more than solar systems, never mind suns.
Sure there's a probability of a collision. But even multiplied by the number if stars, it's still really tiny.
raverbashing · 9m ago
I would agree, except for some factors:
Gravity tends to bring heavy objects together
Andromeda and the Milky Way are not colliding "like two pancakes on top of each other" but at an angle to each other
Also star surroundings are usually places where you can collide with a lot of stuff (asteroid belts, dust, etc)
We're not shooting a goal on a 4 light-year wide goalpost (btw that's the density on our vicinity, but on other areas the density is higher) but passing multiple stars on an environment that can be perturbed and heavy things attract each other
lisper · 2h ago
Damn, I was really looking forward to seeing Andromeda up close. Oh well.
spenczar5 · 2h ago
I could have told you in advance it would have been a Finn! Something in Helsinki has been going on for a while in astronomy. They're so much more willing to challenge the norm, and unusually capable with Bayesian statistics and big computation. It's really remarkable.
This video explores what's predicted to happen in the future of the universe. The speed of time passing doubles every 5 seconds. And the video is almost 30 minutes long.
Good point. With my limited understanding of the cosmos, collisions are inevitable, when they happen depends on which rock you're standing on and how long you're willing to wait.
It's comforting to know scientists are out there, keeping an eye and ear on things.
mensetmanusman · 2h ago
Now that you say that, I should cancel my jewelry insurance!
Aah damn well let me check my calendar for what I'll being doing in 7 billion years instead of 4...
400+ billion stars per galaxy might make each one seem 'dense' but the distance between stars is enormous.
I have heard that it might be possible for one galaxy to pass through another without any stars colliding with each other. I don't have any idea if that is actually true.
> Although the galaxies will plow into each other, stars inside each galaxy are so far apart that they will not collide with other stars during the encounter. However, the stars will be thrown into different orbits around the new galactic center. Simulations show that our solar system will probably be tossed much farther from the galactic core than it is today.
Yes there are a lot of stars. It's a big number. But there's a lot of space. That's a number that's in a whole different league.
For example, the whole solar system is about 2 light-day diameter. But it's 4 light years from the nearest star in any direction. Empty space is thus many orders of magnitude more than solar systems, never mind suns.
Sure there's a probability of a collision. But even multiplied by the number if stars, it's still really tiny.
Gravity tends to bring heavy objects together
Andromeda and the Milky Way are not colliding "like two pancakes on top of each other" but at an angle to each other
Also star surroundings are usually places where you can collide with a lot of stuff (asteroid belts, dust, etc)
We're not shooting a goal on a 4 light-year wide goalpost (btw that's the density on our vicinity, but on other areas the density is higher) but passing multiple stars on an environment that can be perturbed and heavy things attract each other
Milky Way may escape fated collision with Andromeda galaxy (9 points, 10 months ago) https://news.ycombinator.com/item?id=41240641
Milky Way and Andromeda galaxies are already merging (2020) (138 points, 2022, 74 comments) https://news.ycombinator.com/item?id=30494523
Our Dazzling Night Sky When the Milky Way Collides with Andromeda in 4B Years (182 points, 2019, 120 comments) https://news.ycombinator.com/item?id=21327269
This video explores what's predicted to happen in the future of the universe. The speed of time passing doubles every 5 seconds. And the video is almost 30 minutes long.
https://science.nasa.gov/asset/hubble/the-fate-of-the-milky-...
It's comforting to know scientists are out there, keeping an eye and ear on things.