In one universe you are reading an article on WhatCulture. On another, WhatCulture doesn't exist, and neither does this article. In another the article does, but the internet doesn't, and it's being published on stone tablets. If you live in that universe, you should probably be paying attention to the eight-legged dino-spiders that are roaming the scorched Earth you call home.
The concept of alternate realities s one that's appeared in science fiction throughout history, but it's one of those sci-fi concepts that might actually have some basis in reality. Human technology is bringing about the likes of robots and AI like you see in film and books, but apparently we're already living out this particular trope.
Scientific theories about multiple universes have been floating about for decades, and people actually take them seriously! It's difficult to get people on board with "rational" investigations into other fringe and supernatural phenomena, but no less than Brian Cox has chatted about this thing. Brian Cox. Quantum mechanics, different planes of existence, and a hammer that nobody can identify a time for are all compelling pieces of evidence that prove alternate realities are real. In this universe, anyway.