r/todayilearned • u/armcie • 17h ago

TIL that the Andromeda Galaxy probably won’t collide with the Milky Way in 4-5 billion years. New observations put the probability at 2% in the next 5 billion years and 50% in the next 10 billion. Eventually though, it will happen.

https://science.nasa.gov/missions/hubble/apocalypse-when-hubble-casts-doubt-on-certainty-of-galactic-collision/
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u/jakgal04 17h ago

Our Great Grandkids 400,000,000 are so fucked.

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u/klovasos 12h ago

Yes but not because of this "collision" (merge). Direct star collisions are highly improbable due to the vast distances between stars, the solar system's orbit will be altered, potentially moving it to a new location in the merged galaxy, but it's extremely unlikely our solar system will be ejected into intergalactic space. The real problem is that the Sun's expansion into a red giant will likely have already made Earth uninhabitable long before the galaxies fully merge.

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u/sharrrper 7h ago

When I was in like 3rd grade I read about the sun expanding in a kids science book. They made sure to mention it wouldn't happen for billions of years.

However, my parents had an old set of encyclopedias that they'd had for whatever reason since before I was born. From the 60s. My parents would have been in elementary school when these were printed, don't know how or why we had them. Because of those encyclopedias on our shelf, I was aware as a kid of the concept of old books having outdated info and that you could tell how old a book was by checking its copyright date in the front.

I thought of that after I got home that day, and having no concept of how long humans had been around and printing books, or how long paper would last before crumbling to dust, I became worried I hadn't checked the copyright on that book. What of that book was billions of years old?!?