Earth. It’s a beautiful thing, and we’ve discovered so much about how the universe works and how we interact with it. But there are still a few things that we’re still working on trying to figure out. One of these things is alternate universes. There are countless possibilities, for these alternate realities.

Now, let me start off by stating that I’m not an expert in these fields at all, I’m simply in a deep love with the idea about alternate universes existing and how radically different circumstances would be, whether major or minor.

Imagine how different life would be in a world where the allies lost World War 2? Or a world where you chose to go a different college with a different major?

According to Cosmologist Max Tegmark, there are four levels of theorized multiverse.

One the easiest ways I’ve heard people describe the multiverse, in relation to our own is using fish and it's habitat as a metaphor. The fish aren’t aware at all of what’s going on beyond the water, or that elsewhere in the world we have swamps or fish tanks at all. In this instance, we are the fish. And the lakes, fish tanks, and of course the surface represent other universes.

Level One: An Unseen Universe

The most basic understanding of the multiverse is simply, that the universe we’ve already seen and examined is only part of the universe. Currently we’re able to see about 46 billion light years. Level 1 has the theory the space is infinite, and that’s in theory there should be an infinite number of people. Both including myself, and you.

Level Two: The Swiss Cheese Theory

Another theory of explaining the multiverse would to view our universe as a massive piece of Swiss Cheese. This piece of Swiss cheese is always getting larger, constantly expanding. In Swiss Cheese there are holes in that form naturally, this theory states that these holes which are pockets of our own universe that don’t expand. Within these pockets, new universes are born. And within them we see the potential for each of these universes to have its own set of Level 1’s as well.

Level Three: Split Timeline

My favorite theory about the multiverse is the split timeline theory. Tomorrow, I’ll have to make a choice on deciding to go to class or not, or to brush my teeth, or to go the gym. Everything time I make a choice, a new universe is created. One where I made a choice, and one where I made the opposite. As such, with Billions of people making billions of choices, whether minor or major. Infinite earths are created.

Level Four: Mathematics and Physics Upside Down

In this theory it suggests that alternate universes are massively different from our own. In that new universes and dimensions alike, the basic rules of our own universe are flipped upside down. In which the basic understanding of our universe such as two+two, or gravity could not exist at all or be massively different.

Now, what’s just been described is not all the explanations nor all the details explaining the multiverse in its theory. Other ways have been theorized such as Brian Greene's Nine types. I selected Max Tegmark's because I found the very basic concepts of them to understand and explain.

Again, I'm hardly a master of these topics, so I'm likely not giving each of these levels the individual justice they deserve. But these theorizes have yet to be proven, as we look to the future of our own species new discoveries are being made and more theorizes are being made about other topics.

It's possible, although I personally consider it unlikely, that we may find the full evidence of these multiverses existing, and once people find out about these being very real. It would change not only how we view ourselves but the very basics of our universe, opening up an incredibly massive field of discovery. So what does the future hold for the multiverse theory? Only time will tell.