The celestial realm, with its myriad celestial bodies, has long captivated the human imagination.

Stars harbor planets, and planets, in turn, host moons. But amidst this cosmic dance, a tantalizing question emerges: could moons themselves have moons?

If so, what would these secondary satellites be called?

Astronomers Juna Kollmeier of the Carnegie Institution for Science and Sean Raymond of the Laboratoire d'Astrophysique de Bordeaux have ventured into this intriguing realm, proposing the term "submoons," or more affectionately, "moon moons."

While some scientists opt for the term "submoons," the latter moniker has gained traction due to its simplicity and charm.

Gizmodo reported on Kollmeier's and Raymond's quest, initiated when Kollmeier's son posed the question in 2014. The duo embarked on computational simulations to unravel the feasibility of such celestial configurations.

Within our known solar system, no instances of moon moons have been observed. This absence may stem from the demanding conditions requisite for their existence, with precise orbital parameters being essential.

Submoons must orbit their primary moon closely enough to be gravitationally bound to it, yet not so close as to succumb to tidal forces.

Furthermore, there must be sufficient distance between the primary moon and its parent planet to prevent the submoon from being ensnared by the planet's gravitational pull.

Currently, only four moons in our solar system meet these stringent criteria: Earth's moon, Callisto, which orbits Jupiter, and Titus and Titan encircling Saturn.

However, a crucial question looms: How would a submoon come into being? Sean Raymond elucidated this aspect, stating, "Something has to knock a rock into orbit around the moon at the right speed for a satellite, rather than a planet or star."

Subsequently, gravitational forces must delicately maintain equilibrium to sustain the submoon's orbit.

Nevertheless, the stability of such configurations remains precarious. A submoon drifting farther from its primary moon would upset the gravitational balance, leading to its eventual demise as it hurtles towards the lunar surface.

Michele Bannister, a planetary astronomer at Queen's University Belfast, shed light on the potential size of submoons, suggesting that they are likely diminutive.

She remarked, "We think we can say with certainty that there are no submoons around Jupiter or Saturn that are more than 1 kilometer in diameter. At most, skyscraper-sized submoons exist there, but these are rather small."

Detecting submoons beyond our solar system poses an even greater challenge. The likelihood of discovering large submoons remains exceedingly low for the foreseeable future.

However, Kollmeier's research lays a robust foundation for future investigations into this enigmatic phenomenon, offering valuable insights into the formation histories of planets and their moons.

In their paper, Kollmeier and Raymond articulated, "While many planet-moon systems cannot dynamically accommodate long-lived sublunar systems, the very fact that submoons are not found among known moons and exomoons provides important clues about the formation mechanisms and history of these systems."

Thus, although moon moons have yet to be observed, their hypothetical existence beckons astronomers to explore the intricate dynamics of celestial bodies further.

As humanity's understanding of the cosmos continues to evolve, the quest to unravel its mysteries remains an enduring endeavor, driving scientific inquiry to ever greater heights.