Thread: Need advice on setting: Post-Apocalyptic/Futuristic Earth, or Alternate Universe?

So the book I'm writing right now currently takes place on Earth several hundred years after a calamity that destroyed pretty much everything and left only a small percentage of survivors. Since then, new civilizations have arisen, and technology has been remade to the point where it's slightly more advanced than it is now (in the real world).
Lately, however, I've been having trouble figuring out if I want to keep it in this setting, or if I want to change it so that it's in a completely alternate universe altogether. One of the main reasons I'm having this debate with myself is that there are certain elements of my book that seem a little too fantasy-like to fit into a futuristic sci-fi story. Chief amongst these elements is the existence of sentient beings made of pure energy. Not only that, but anyone possessed by these beings gains the ability to siphon the life out of any living organism, and they can also sense and influence emotions, and lots of other abilities. I've tried as hard as I can to describe them in a way that makes them sound plausible, but I'm honestly beginning to think that these things are just a little too far-fetched for a Sci-Fi Story that takes place on Earth (and I personally don't want to make it a Fantasy story on Earth).
I plan on keeping the overall story the same, but my question is, would I potentially have more to gain or lose by changing the setting to an alternate universe that I create, as opposed to placing it on my own vision of Earth about a thousand years in the future? My brother says that alternate universes are "cliche" and that sci-fi stories that sound at least semi-plausible are a lot more interesting, but I still can't decide if I agree with him on this. If I end up doing the alternative universe, I plan on mixing fantasy with science fiction (as in there is advanced technology and stuff, but there might also be magic or mythical creatures and such).
Anyone have any thoughts on this?

I say you just leave it ambiguous. Don't explain the entire backstory of the planet, but just tell the story. Let your readers debate whether this is the same earth or not. You can probably get away without even using a planet name, unless you have interplanetary travel.

It sounds more science fiction to me than*alternate*universe, but I'm not an expert in either field. I think your energy beings are very plausible, I read a short story that who described a race of aliens who were essentially pink blobs that evolved into different organisms as and when the needed to in order to survive. It seemed perfectly plausible because when we think of life on other planets, I think we hope that it's going to be as different and as exciting and as challenging to understand as possible.

How disappointing to find a distant planet entirely inhabited by accountants *

Sixty years ago (seventy?), science fiction WAS fantasy. People would go to other planets and meet mythical creatures; not just aliens and robots. And there's no reason why you can't do the same. Leave the energy beings in and let it be the normal universe. Nothing wrong with that.

Wow, you guys gave some pretty good advice!
The way I personally view science fiction is that it's far-fetched, but seems like it could happen. That is why (and may God strike me dead if this is blasphemy ) I personally see things like Star Trek as both science fiction AND fantasy, because there is a lot of stuff in that series that I don't believe could ever happen in the realm of reality. I find stories more interesting when they are presented in such a way that they seem like they might be possible in the real world, even if they don't actually occur. (And don't get me wrong, I'm a huge Star Trek fan. )

Originally Posted by j.w.olson

I say you just leave it ambiguous. Don't explain the entire backstory of the planet, but just tell the story. Let your readers debate whether this is the same earth or not. You can probably get away without even using a planet name, unless you have interplanetary travel.

Yeah, since this is in a 700-years-post-apocalypse setting, people in the world remember very little about the "old world", so I never actually mention that this is on a remade version of the Earth that we know. And I don't use interplanetary travel, partly because the technology isn't that advanced, but also because - if I wanted to make it semi-realistic - it would require a huge amount of time and a ridiculous amount of resources that aren't really available to the people of this world. If I ever used space travel in any of my books, it would be the kind where the first people who begin the journey won't live long enough to see the end of the trip, let alone return to Earth afterward (though their great great grandchildren probably will).

Anyway, back to the subject at hand. I did have an idea to explain the energy beings. Rather than being made up of pure energy, they are actually clouds of these microscopic organisms that carry energy and genetic data inside of them, and when they inhabit a physical body, they become sentient because they now have a brain to act as a sort of "control center".
With that idea in mind, I think I might just stick with the "Earth-Reborn" idea.