Is It Possible for a Moon to Own a Satellite?

Most of the solar system members have moons accompanying them as they hover around the sun. Even some exoplanets, or the bodies outside our galaxy, have satellites that rotate with them in their respective neighborhoods.

Moons and Submoons

Although moons were already established as lesser companions of planetary objects, there are still mysteries around them, such as how they formed and their true nature during the early age of the universe. Among these subjects, many people also guess if ever the moon can form its satellite.

Our planet has a single moon that revolves around us at a particular time. Only Venus and Mercury do not have any natural satellites of eight of the solar system's planetary bodies. In recent studies, there have been exomoons located somewhere beyond the galaxy, but the possibility of a moon having its moon remains unsolved to most of us.

Hints to answering this problem anchor to the properties and structures that define a moon, according to Sky at Night.

A moon is a cosmic object with other materials such as space rocks, stellar bodies, and planets. The common attribute is that it should revolve around a host planet, similar to the setup of Earth and its lunar companion.

Scholars from the Observatories of the Carnegie Institution of Washington and the University of Bordeaux have already conducted a study to answer the question.

According to a report by Carnegie Science, Bordeaux's Astrophysics Laboratory specialist and co-author of the study, Sean Raymond, explained that it is normal to question the possibility of smaller moons orbiting larger satellites due to the association between relative bodies, such as what we perceive from parent star-to-planets and planets-to-moon.

Throughout the history of the astronomical field, there is still no evidence of a submoon orbiting any other moons, EarthSky reports.

Submoons Possible, But Not Does Not Exist

Carnegie expert and lead of the research Juna Kollmeier said that the lack of the submoons in our system's perimeter is enough for us to understand how the neighborhood of planets around us formed and how probable it is for a moon to support its natural satellite.

In the study, the experts concluded that, if existent, submoons can only be held by larger moons with a wide orbital direction. This is because bigger submoons revolving around a smaller host would disrupt its stability. Moreover, it will cause a non-uniform concentration of mass to a planet's crust.

Another theory is based on the origins of the moon. The most possible scenario of how our own lunar body formed is that it materialized after a massive collision of Earth with another body that scales to the size of Mars.

According to the authors, many factors make it impossible for a sub mood, even a smaller one, to orbit a parent moon due to the instability it demonstrates compared to the natural setup Earth, and its neighbors have with their respective moons.

Further observations from distant exoplanets are needed to finalize the real answer to this cosmic question.

For now, the only possible way for a moon to be accompanied by its satellite is through the construction of an artificial one, similar to what NASA plans for their upcoming project called the Lunar Gateway.

The study was published in the Monthly Notices of the Royal Astronomical Society: Letters, titled "Can moons have moons?"

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