This content has been rated S for Spoilers for Fallen London, Sunless Sea, and the pre-production of Sunless Skies.
"Wells are Sunless Skies’ version of black holes. Wounds in the world. Fathomless. Hungry. Well-winds, flickering with candle-flames, push unwary captains into their pull. Certain unspoken cults gather at their rim to perform distressing rites. If an enemy is too inconvenient to kill, the courts of the heavens consign them to a well. Do not stray too close. Ignore any voices within."
In a Sunless Skies pre-production blog, this is the description of a more "primal incarnation" of wells. There’s a little I believe we can glean from this text, given the right context, and while my hypothesis is most likely entirely wrong, it’s still fun to speculate. As a warning, information from a Fate-locked Destiny will be mentioned tangentially, but if that’s an issue, I’ll be happy to remove all references.
Anyway, to begin, the idea of a "wound in the world" has appeared in Fallen London before, in a few of the Destinies.
[spoiler]A chuckle in the Correspondence is the crackle of broken light. "And still, my dear, I do not believe you! I do not. One always becomes fond of one’s travelling-compansions. Why, I have grown very fond even of our new associate here. Lowly origins notwithstanding." You know without employing any of your sense that he gestures at you, and at the wound-in-the-world far, far behind you.
If you choose the (Fate-locked) option to obtain The Road, you gain one more snippet, saying:
The Bazaar, the Sun, the world of your birth, are grains of sand on a beach. Even the Neath is a dark and tiny wound."[/spoiler]
This could very well be a coincidence; the idea of a "wound in the world" is poetic and compelling, a phrase I’d use again and again because it’s just that good. Failbetter keeps track of the stories it writes, though, and for Sunless Skies, I’d imagine they’ve looked back at read everything they’ve written about the Judgements and the High Wilderness. The Forge of Souls, for instance, is first mentioned in this destiny and again with the Merchant Venturer, and it’s now making its appearance in Sunless Skies. The dragons which consume time have appeared here and in the Seventh Letter, and now they’re making their appearance in Sunless Skies. In short, there is a chance that this is not a coincidence, and that’s the place where this hypothesis nests.
In that case, we can conclude that the Neath is a wound-in-the-world, or in other words, the Neath is a Well. Or, at the very least, something very much like a Well. If an enemy is too inconvenient to kill, the courts of the heavens consign them to a well. It would appear that wells are places where the Judgements hide the dangerous and the powerful, and as wells are black holes, the light of the Judgements will be able to enter but never return.
Perhaps this means they cannot see what lies within the well, and thus they cannot pass judgement or enforce their Law. Perhaps what light that enters gives a measure of order to the well; basic ideas, like semi-linear time, gravity, electromagnetism, nuclear forces, etc. These remnants of the Law remain even when the Judgements are gone because their light hasn’t died; it’s merely been trapped in darkness. And, of course, their rules can be bent; death can be avoided, amalgamy committed, and so on, because that light and Law cannot escape. After all, the Neath is hidden from the eyes of the Judgements, but things are still pretty normal as far as physics and chemistry are concerned. The Neath is more lawless than other places, but it is not entirely without light and law, and this could explain why all that light and law isn’t enforcing the law very well.
They say that the Neath is where the Earth hides its shame. The Mountain of Light was hidden away because of its parentage. The breaking of the Chain. The defiance of the laws of the Judgements. What better place to hide these shames than in a Well, beyond their watching eyes, where they will be trapped, unable to escape the darkness. If you remain in the Neath after sending the Merchant Venturer to the High Wilderness, you have this extra piece of text: "As your eyes recover, far, far, away, in the uttermost South, you glimpse a pulse of ruddy, envious light." The uttermost South is the Mountain, and it is "envious". As if it wants to go to the High Wilderness. If it were truly imprisoned and thrown down a well, that’s understandable. The Neath then is its prison, and it wants out.
One of the key points of a black hole (a non-rotating black hole, just for simplicity’s sake) is the singularity, a point where the curvature of spacetime as caused by gravity becomes infinite, creating a region with a volume of zero containing all of the mass of the black hole. Or, in simpler terms, "____ you" to science and mathematics as we understand it, at least until general relativity and quantum mechanics finally stop dancing around the topic and finally get together so we can answer these questions and move on to the next level of unanswered questions. But I digress.
In Sunless Sea, passing the Avid Horizon and travelling all the way NORTH takes you to the place that is no place. A place where space is forbidden and time contracts to a single frozen instant. It is a point, a singularity, and beyond it, the entire Neath awaits. It is the High Gate, a law guarding the passageway into the High Wilderness. It’s not precisely a singularity in the scientific sense, but this isn’t precisely a hypothesis in the scientific sense either. Regardless, what I’m proposing is that the High Gate is the singularity of a black hole (a Well), and the Neath is what exists on the other side.
Likewise, this hypothesis posits that when the Masters and the Bazaar depart from the Neath, they leave through the Avid Horizon, just as the Merchant Venturer did, and emerge from the wound-in-the-world and prepare to meet the Sun. They blind the watchers at the gate, who stand to make sure that the Law is followed. The Law states that nothing may escape from beyond the event horizon of a black hole, but if the watchers are distracted for a moment, the Law may be broken, and things may emerge from the black hole, from the wound-in-the-world.
If you want to really go off the rails and into mad speculation, you could say the Deconstruction in the uttermost East represents the (entirely hypothetical) other side of the event horizon, not a singularity but rather a boundary between the Well and what lies beyond. It is probably coincidental, but it should be noted that the NORTH is marked by the Avid Horizon, while the East is often referred to as the last horizon. This, perhaps, is the temptation of Salt (though I’ve not yet finished Seeking, so any speculation on my part could be completely debunked by that): to go where no (star) has gone before, to emerge from the Well not into the sunless skies, but into green-and-gold and glory. And where is the place where the NORTH and the East meet? Irem. The place at the border of Parabola, where time is mutable and strange - one of the weirdest places in the Neath. But this is pretty much baseless speculation at this point, so I’ll just stop there.
To summarize, I’m positing that the Neath is a well - a black hole - or something very similar. Yep. There were all of those paragraphs when it could’ve just been that one sentence. And, in the end, it’s all just speculation, and it’s most likely not even true. There are plenty of holes to poke in the hypothesis. First, it’s really a bit of a stretch. Its fundamental premise is literally one phrase from a pre-production Sunless Skies blog post that happens to match a phrase appearing in one of the Destinies in Fallen London. The rest is just circumstantial evidence; helpful in supporting the case, but useless if the premise is wrong.
Second, in the Destinies, the Masters and the Bazaar have been travelling for fifteen years. Now, there is an older and far likelier piece of speculation that proposes that the "Mother of Mountains" is the Sun. In the pre-release material for Sunless Skies, we’ve seen that Albion exists around the Avid Horizon and that hours are mined in the Reach, indicating that the Mother of Mountains is there. Unless the Bazaar is the cosmic equivalent of a snail, it should not take fifteen years to go from Albion to the Reach, considering how it took London ten years to spread its influence that far. It’s stated in the Conversation on the Road that your entourage has to slow down significantly as it approaches the sun, and maybe with the Liberation of Night, travel ‘between stars’ takes less time, but we simply don’t know enough to say.
Third, even if the Neath is inside a black hole, there’s no reason for it to be connected to the Earth. The Copernican principle is always a good one, and there’s no reason for Earth to be special enough to have its own personal black hole. The Cumaean Canal clearly shows that travel is possible out of the inside, and it appears to just be a marvel of engineering, not a marvel of defying the laws of the Judgements, and the Travertine Spiral is an even more low-technology version. It’s kind of stupid to have a supposedly inescapable black hole that’s so easily escapable. I’m open to the idea that the Neath is more something very similar to a Well - an imitation of sorts. After all, in Sunless Skies, planets are prized as "places of expression and experimentation for the bright regents of the heavens; warded, prized, inviolate." It’s entirely possible that the Sun tried to create its own black hole in the Earth, and that tiny wound-in-the-world became the Neath. Of course, that’s even more baseless than the rest of my post, so it’s hardly a solution, but it’s fun to speculate nonetheless.
And, credit where credit is due: this train of thought exists because of this. Begin with What if the Neath were a well? and then run with it. I hope you enjoyed the read, if you read it, and again, most of this is probably way off the mark, but speculation is fun and hype even more so. When the well of new lore on the High Wilderness runs dry, one has to grasp onto whatever they can get, and here we are.
Feel free to poke all the holes into this as you want.