A "moonmoon" is a whimsical term denoting a moon that orbits another moon. The alternative term "submoon" is also occasionally used, though its origin remains unclear. Similarly, "subsatellite" is utilized, but it does not align precisely with the definition of a moon, as satellites can be artificial constructs.

It is not unusual for various fragments of space debris to find themselves orbiting larger celestial bodies, which we often recognize as planets or stars. However, a true moon typically refers to an object of adequate mass and size that can maintain a roughly spherical form and possess distinct surface characteristics — essentially, a mini-planet in its own right.

While our solar system lacks genuine moonmoons, the ongoing research into exoplanets continues to yield surprising discoveries. Although no confirmed "exomoonmoon" has yet been reliably identified, at least one substantial exomoon has been detected, suggesting that certain distant planetary systems might support large moonmoons in stable orbits around unusually massive moons of gigantic planets, which we do not have in our immediate vicinity.

The moonmoon that inspired this discussion is a hypothesized Neptune-sized moon orbiting the planet Kepler-1625b, an enormous "superjovian" with a mass approximately twelve times that of Jupiter.

Typically, celestial bodies around thirteen Jupiter masses are capable of initiating deuterium fusion, categorizing them as brown dwarfs and causing them to emit infrared radiation like a frigid star. Kepler-1625b completes an orbit around its star roughly every four days, positioning it as a "hot superjovian" given the spectral characteristics of some aggressive stars. Interestingly, despite having a mass comparable to our sun and a similar spectral type, Kepler-1625 is slightly cooler, with Kepler-1625b located on the inner edge of what is deemed the "Habitable Zone."

While these findings suggest that Kepler-1625b is an intense environment, it does not reach the extremes associated with a brown dwarf, although it sits on the hotter edge of what might be considered "comfortable." It's essential to note that the criteria for habitable zones in extrasolar planets are often arbitrary estimates, and there's no compelling reason to assume that even a brown dwarf could not host its own system of moons and moonmoons, some of which might be habitable to various forms of life.

Interestingly, the parent star is thought to be a "yellow giant," indicating it is in a later stage of stellar evolution. This star has likely experienced an increase in luminosity and temperature, and it may now be nearing the conclusion of that phase.

Consequently, Kepler-B (for convenience) may have spent a significant portion of its life within a more favorable habitable zone.

Somewhat disappointingly, recent observations regarding the potential moonmoon of the Neptunian moon, or "neptmoon," have raised questions about its existence. This uncertainty also casts doubt on the reality of the "exoneptmoonmoon" — a term coined by a writer whose name I cannot recall.

Nevertheless, this speculation is not without merit. The formation of moonmoons, even large ones, is not physically impossible, and even if the exomoon of Keplerneptmoon is not real, it is highly likely that similar configurations exist elsewhere.

If you, dear reader, are familiar with my article on Hycean worlds (essentially sub-Neptunian pseudo-Super-Earths), we can quickly delve into the possibility that, among the larger and habitably anomalous Hycean worlds, there could be examples that lean more toward Neptunian characteristics, or Neptunians that exhibit sufficient Hycean traits.

Neptune itself is an incredibly hostile environment. While Hycean worlds have some leeway due to their less energetic atmospheres compared to true gas giants, Neptune is unyielding, with a cryogenic climate that adds to its alien nature.

In fact, Neptune is arguably the most meteorologically violent planet in our solar system, characterized by permanent supersonic winds and the phenomenon of diamond rain — a truly fascinating yet lethal aspect of this exotic world.

Neptune does not possess a traditional ocean, as there is no clear transition between gaseous and liquid states due to increasing pressure. However, it could potentially possess such an ocean if it were even colder than the current assumption of 55 Kelvin, which would lower the condensation point of the wet haze present.

These hypothetical oceans would consist of uniquely alien mixtures of water and ammonia, a captivating concept despite the improbability of cryogenic whale-monsters emerging from Neptune's depths. This serves to illustrate the vast array of strange and unexpected variations that can arise throughout the universe.

Now, let’s consider an intriguing scenario involving an extreme superjovian located within its parent star's habitable zone, accompanied by a Neptunian moon that we will generously classify as more akin to a particularly extreme example of a Hycean world.

This assumption is not entirely unfounded, as tidal heating from the interactions between these two massive planets could generate significant internal heat, in addition to potential radiative heating from Kepler-B, contingent upon the accuracy of our mass estimates.

Neptune has a relatively small moon, Triton — less than half the mass of our Moon, yet larger than Pluto and one of the largest moons in the solar system. Despite Triton's icy world and negligible atmosphere, it exhibits cryovolcanism — the eruption of freezing cryogenic fluids — attributed to tidal forces that maintain an inner heat reserve through gravitational friction with its parent planet. This has led to speculation that Triton might also be among the hidden "ocean moons" of our solar system, although perhaps not as oceanic as Europa, which boasts a tantalizingly deep alien sea encased in ice.

Similar tidal forces could sustain geological activity, provide a source of internal heat, and potentially create a magnetic field that protects against atmospheric erosion from solar winds in our hypothetical moon existing in a more energetic system.

While slightly warmer conditions can be beneficial, low-mass celestial bodies near stars struggle to retain their atmospheres due to their thin nature, which makes them vulnerable to solar wind stripping. However, exceptions do exist, such as Titan.

Titan is fascinating because it resembles Earth while being radically different. It appears to have a geology strikingly similar to ours, along with oceans, seas, and landmasses — although these bodies are composed of hydrocarbons, essentially oil. Titan has managed to retain a thick atmosphere, but it is extremely cold, posing challenges for any Earth-origin biological entities attempting to operate in its frigid environment.

These challenges could potentially be addressed by breakthroughs in power generation, such as portable fusion batteries, or advancements in materials science that develop "superinsulative" materials reflecting 100% of infrared radiation back for reuse. However, for now, let's select a few appealing elements from the worlds we've examined to construct our hypothetical triad of astrophysical and astrobiological peculiarities.

Thus, we envision a Superjupiter — potentially radiating heat, or at the very least, astonishingly vast. Orbiting it is the Neptcean moon — a blend of "Neptune" and "Ocean," representing an unlikely yet not impossible set of circumstances that might enable life to flourish in ways we can scarcely comprehend.

Orbiting Neptcean could be a Titan-like moon. Or perhaps we could envision an even larger body? Mars, perhaps? I won't delve into the calculations here; there is a time and place for that. Admittedly, the larger we speculate, the greater the risk of a historical version of our improbably large moon spiraling too close to its parent planet and becoming a ring system over millions of years.

Nonetheless, unusual orbital dynamics can occur. Pluto and Charon, while considerably smaller relative to the giants we've discussed, exemplify a rare double planet system, orbiting closely enough to share an atmosphere during certain seasons (though thin; don't expect Plutonian birds taking flight). Their nearly identical masses and nearly circular orbits (low eccentricity) suggest a future where advanced humanity could construct a bridge akin to a space elevator, facilitating transport between these two distant worlds.

I presume this scenario unfolds in an era when humanity has matured sufficiently to avoid making foolish statements such as, "Well, I don't agree with everything Andrew Tate says, but he has some good points." If you've ever uttered such a phrase, I bid you farewell.

Apologies to the rest of you for that outburst; I've been spending too much time online.

While double-planet dynamics are less common among larger celestial bodies, let’s entertain the possibility of a moonmoon slightly less massive than Mars. Unlike Mars, this moon possesses an active magnetic field, which, coupled with the substantial magnetic flux from Neptcean and Superjupiter, contributes to an active geological cycle, a thick atmosphere, and a climate that is neither as cold as Titan nor as hot as Venus. Should our current understanding of abiogenesis hold any truth, life could potentially emerge here.

Life may also arise on the Neptunian parent, albeit with more challenges. Thus, we have two out of three planets in this triad where life could potentially evolve independently.

Moreover, considering the close proximity of these potentially habitable worlds, relative to anything we've observed directly, along with the volatile environments typical of massive planets (which attract various space debris) and the intense radiation flux associated with planets as "small" as Jupiter, we have a unique scenario conducive to panspermia, allowing life to spread from one world to another.

As a caveat regarding our upcoming discussion of "Superjupiter," it is important to note that gas giant atmospheres generally do not create the right conditions for the chemical processes that could lead to life. Nevertheless, the points made thus far are speculative — albeit reasonably informed speculation. My next assertion is purely my own opinion and may be wildly incorrect.

Planets located on the threshold of brown dwarf classification, where fusion processes might facilitate the upward movement of heavier elements, could mean that life arriving through panspermic events might endure longer than it otherwise would.

This may seem far-fetched, but it’s conceivable that we could have three planets capable of supporting life. Each would undoubtedly exhibit different forms of life, particularly the superjovian. Having established this scenario, we can envision numerous possibilities for concurrent life evolution on three distinct worlds and how this might radically influence the psychology and culture of those beings who come to understand the extraordinary circumstances surrounding their existence.

Let’s explore a few potential outcomes. It's impossible to predict where life would emerge first, although intuitively it seems most likely to arise on the moonmoon, which is by far the most environmentally stable of the trio. Life may independently develop on the Neptmoon or through panspermia from microbial-laden meteoric debris that eventually falls back to Neptcean. The same process could apply to Superjupiter.

Of course, the emergence of life does not guarantee the development of technology, sentience, or anything of the sort. However, assuming that life does arise, what happens when the more exploratory species discovers that there are potentially sentient beings living just next door?

This realization could have a profoundly positive effect on the mindset of such a species.

Considering our own evolution in relative isolation, humans have, understandably from an evolutionary perspective, always viewed themselves as unique and special.

We may indeed be! Earth could be the sole extreme outlier event, the only bastion of self-aware, self-analyzing life in an otherwise sterile universe. However, this belief fosters a detrimental side effect; without the knowledge of anything truly significant beyond our limited perspectives, we struggle to redirect the tribal instincts that once helped us outcompete other protohuman species on prehistoric Earth. These instincts now threaten to undermine us due to our collective inability to envision goals beyond competing with one another.

For the most part, humans find it challenging to recognize ourselves as a single human tribe, potentially the guardians of consciousness in a dark universe, and that we ought to focus our efforts on this rather than engage in trivial squabbles that ultimately do not matter.

This article will have a follow-up section that delves deeper into the biological, civilizational, and technological dynamics of our hypothetical reality, highlighted by the Moonmoon of the Neptcean moon of the imagined planet Superjupiter — loosely inspired by the real Kepler-165b and its tenuous moonmoon.

In the meantime, it is crucial to acknowledge that our isolation as a sentient, spacefaring species may hinder our ability to overcome our self-destructive tendencies and create a better world.