Yeah nothing in the game actually necessitates that the Chaos Emeralds be a natural part of Earth, and the Gaia temples don't really make sense in an idiom of the Gaia Cycle itself without someone to...I guess bring the emeralds to the temples every single time? Seems like a lot to bank on, given that there's one on each continent and the world possibly splits apart each time. I always figured people built the temples, possibly because of some prophecy that Light Gaia itself one day wouldn't be able to handle the problem or something. If you wanted to expand on this, you could make the argument that all the weird shit going on in this series is because humans weren't destroyed in the last cycle because the emeralds were never meant to be on Earth. Maybe a world of only furries is what we were supposed to be living in this whole time, and humans are a relic of the past that shouldn't have stuck around.
This is something that irks me in this franchise... Purposely leaving some things ambiguous to keep the community guessing and theorizing, but never giving a solid, definitive explanation or solution. It's a way to keep us going, it's true, but it's also a way to divide people and opinions; a double-edged blade.
Going to be a bit headcanony, but I think it's the other way around and the Anthros are the ones who aren't supposed to be on Earth. Rather, I suspect they're the descendants of the Ancients: the Chao are my primary consideration for this, since they are confirmed descendants yet take on traits from animals from Earth, while the Anthros have similar feet that lack toes. I think the common ancestors took on traits of various Earth native species, until the Anthros 'stabilised' into their modern forms while the Chao retained the ability to imprint animal traits. Effectively, the Chao, or a common Ancient Ancestor, are the Mew of the Anthros. EDIT: I've also just realised the irony that, yes, Sonic and friends would technically be aliens with this headcanon when I've argued against such a thing before when the Two Worlds Canon was a thing. Funny how that swings back around...
The fact that some people lean into their own personal head-canon and don't accept other opinions...isn't the fault of any series.
And why do you think there are headcanons, to begin with? At least, in this case, it's due to the leeway SEGA gives the fans for such... Of course, headcanons come up whether things are properly explored or not...
Things can be as plain as day and people will still come up with their own interpretations...believing it to be the only correct interpretation. You can't control that. I'd say it's their right, but some people are just really bad at paying attention to the text...not subtext, just clear cut text.
In some scenarios that's simply the best thing TO do. The Chaos Emeralds are a perfect example of this, I wish they'd left them as they were before Frontiers.
I really hope that the follow up to Frontiers ends up saying the Ancients were unknowingly returning the Emeralds to Earth, with their true history and origins being totally unknown.
See I get wanting the emeralds to be unknowable, I just don't think a mystery you never learn the true answer to works as well when the object of that mystery keeps being a necessary recurring plot macguffin. If they kept making Pulp Fiction sequels that reestablish nobody knowing what was in the briefcase over and over, that would just be really annoying. For example, I don't want to know Sonic's backstory or the reason for his speed or whatever, because Sonic speaks for himself. If he's from somewhere, his backstory should actually be boring on purpose, because it's what he does thar makes him cool and interesting. All the chaos emeralds ever do is get fought over and act as magic batteries sometimes. I don't think the series would be hurt if you established they were all incarnations of legendary warriors with distinct personalities and backstories, or each tied to a specific dimension with it's own history and version of the world, or jewels in the crown of the ultimate god of reality or whatever. There's nothing sacred about them to me, they're rocks. Their ultimate contribution to the narrative and themes of Sonic are the way so many societies coveted and worshipped these...rocks. What they actually could be doesn't detract from that, if you ask me. I mean, the problem with the alien thing was never the literal biological history but the portrayal of Sonic and friends as not being a natural part of the setting, and if the source of that is many thousands of years in the past, it has enough time to become ingrained. That being said, I think I just prefer the "furries meant to replace humans but humans survived Dark Gaia thanks you the emeralds" thing because it paints humans as the aberration, the disruptive influence on something that is otherwise more peaceful...which is the role they've often played in the story. That's Doctor Eggman, after all. Thematic parallels! This is what happens when humanity tries to cheat natural selection.
I'm not sure how I'd feel if the emeralds were 100% confirmed to be from space though, mostly because thematically they are supposed to represent the power of the planet/nature itself. Additionally, with the focus on them being 'infinite energy sources', you could probably read something into it about renewable vs non renewable energy. Having them be from space would mean making them both not natural and not renewable, and like thats not bad but at that point what are the emeralds even supposed to represent thematically? My biggest issue is with the master emerald. We're told it "controls" the chaos emeralds, but like... what does that mean? Can the master emerald "turn off" chaos emerald abilities? The CEs didnt seem to lose power while the ME was broken. If the master emerald is so much better, why does eggman even bother with the regular emeralds? Did knuckles use the master emerald to knock sonic out of super? Why is guarding it even important like there are only two guys who ever want to use it and they both seem perfectly content just using regular emeralds?? Why is it green when there is already a green chaos emerald????
I feel like not knowing the origin of the emeralds and them being "from space" are one and the same. They could've been from anywhere, a part of anything prior, and I don't think saying they didn't originate on Earth does anything to harm that. They may have been important to the Ancients, sure, but they're important to everyone to everyone on Earth too. I'd say they're probably important anywhere they end up. I don't see what the problem is..?
I just think leaving some stuff unexplained adds a little more depth to a story. Sort of how in real life there are things that are unexplained. In a way we still don't know much about their origins or the Master Emerald. Not a fan of them being from space but I think that's as far they should go. I don't think we need another story of why they were on the Ancients planet or how they were created. They're sort of like Sonic to me, they just are and that's all I need to be honest. Saying that, I'm not surprised that Sonic Team went with that angle. Black Doom knowing about them and having an ability that's linked to them. The Metarex in Sonic X knowing about them. The Babylonians being aliens and stranded on earth. Chaos and the Chao having an alien-ish design to them. Sonic Team really dig the alien angle.
I really dislike the emeralds being from space because it's a non-fact that contributes nothing to their status as a mystical and foundational entity on the series, while also being a fact that rubs me the wrong way when it comes to the implications on the various peoples that built some sort of religious tradition around it (Knuckles clan, Trip's lizard ancestors). Reminds me of the whole racist Alien Pyramids theory, unintentionally as it may have been. And even if I ignore that, it's like @Hoiyoihoi said-- okay, but what are they even supposed to be? Like, they originally were this overly irrational power that Sonic can use to fix what an overly rational man did to an irrational force, nature. You could say them being from space doesn't change that, but it also... adds nothing to it. It's distracting at best.
I mean, religious culture developed around tons of shit both in and out of universe. The ancient alien shit is racist because it's erasing the cultural history of ancient peoples and arguing that not only were they too small minded for their religions to employ, y'know, metaphor, but also that their lying religion pales in comparison to this alien shit, because oh that's all real and scientific. Chaos emeralds are more like the moon. Every culture has tons of stuff to say about the moon, but we learned a lot when we actually studied it up close. The chaos emeralds are real things in Sonic, their power is real, them not being from earth is just one thing we happened to learn about them. I will concede though that as of right now, the fact that they're from space doesn't actually impart any realization or deeper meaning about them.
Gonna play devil's advocate here and say I actually like the idea of them being from space even if nothing interesting was done with it in frontiers. "Nature" would rationally extend beyond earth as a concept. There are a lot of things that were natural before the earth and there will be more after the earth is gone. To centralize the concept of nature around the earth is short-sighted, I think. I also think that it explains why so many extraterrestrial entities happen to know what the chaos emeralds are. These things might have been the center of culture and conflicts going back years and years. The series as we know it now might just be a footnote in their history. I find that really fascinating! I like the chaos emeralds as an endless rabbit hole it's impossible to see the bottom of. Make it even more dense if you want. I don't care. All that being said I DON'T like Frontiers's take on this because of the need to tie it so aggressively to Sonic Adventure 1 when the themes of A have almost nothing to do with B aside from some aesthetic choices. Chaos as the product of long generational conflict involving the emeralds is kind of interesting I guess? But that's all I got.
Fair (also Wraith has a fair point too), I think your comparison is more apt -- but it's still a taste in my mouth I don't really like going from "hey these ancient people were on to some mysterious shit huh" to a piece of knowledge that makes then look like space cargo cultists. It doesn't change much! It's a nitpick. But I *would* like them to be more focused when worldbuilding. Also, I can get not centralizing nature on Earth, and we've had a LOT of aliens lately (actually like half the games have been about aliens since Shadow the Hedgehog. Huh), but it's not like the series is actually doing anything cohesive with it. Sonic and Eggman aren't space explorers and, unlike (say) Dragon Ball Z, there isn't a sense that Earth is a hot spot for aliens because the hero is there so it's in constant danger. The aliens are kinda bad, sometimes? But not always? And not particularly? Shadow plays a nice role, having been transformed into a hero born from "evil nature" instead of pure biotechnology, and that inherently discusses nature vs nurture etc., but it's not like Sonic reeeeeally explores nature outside of Earth much. There's the Wisps, and that's about it.
I feel like they're going to keep baiting us on what exactly the Emeralds are and where they came from, but never actually give an answer. So if you think the fact they're from space is interesting? Cool, speculate away. If you don't like it? Also cool, because 9/10 it's not going to be referenced or followed up on past Frontiers, so you can just pretend it never happened. The Emeralds just "are" to me, they exist and let Sonic go Super Saiyan and I think that's how Sonic would look at them too. Ver
I wonder if they're going to retcon Chaos from a mutated Chao to the last survivor of the Ancients...
I don't really get the problem peeps have with it, to be totally honest? Ancients devolved into Chao, and a Chao mutated back into a form similar (if not wholly) to the Ancients, ie the closest and only known decendant. It's literally the best case scenario and makes complete sense. I'm not gonna expect a larvae to, like, go into a cocoon and come out looking like a kitten, y'know? I'm expecting there to be a part I'm missing from the whole equation, so if anybody would like to explain further then please do!!
Oh, I was just musing it, not wanting it. I think I've been clear that I don't like them going back and just outright overwriting things, but since it's not actually been mentioned in the games, they technically have free call on doing that.