Title text:
The family lore was that we've had it ever since it was ejected from a star-forming gas cloud, but it seems more likely that my great-grandparents probably just bought it while on vacation in the galactic thin disk.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3281/
It's like how Earth-2 had the characters introduced in the '30s and '40s while Earth-1 had the retooled versions from the '50s and '60s.