Bigger Moons Have Moons, And Some Are Calling Them 'Moonmoons'

Mindy Sparks
October 14, 2018

It is natural to ask, can submoons orbit moons? The study, however, has raised an even bigger question that now has the scientific Twitterverse riled up.

No known moons have a moonmoon, but Sean Raymond and Juna Kollmeier, the astronomers working on the paper titled "Can Moons Have Moons?" argue that the existence of such a moon is possible given the right conditions. They found the orbits would be stable with 10 kilometer-scale moons orbiting larger, 1,000 kilometer-scale moons, according to the paper.

Breaking down the tidal considerations of a moonmoon in the October 9 arXiv preprint server paper, Kollmeier contends "moons may migrate inward and crash into their host planets or migrate outward until they reach the stability limit".

For a submoon to survive, it needs to be small-about six miles in diameter or less.

Theoretical calculations showed that if the moon is sufficiently large and rotate quite far from their planet, then it can be own "subline".

Within the Solar System, four moons now meet that particular requirement: Earth's Moon, Jovian moon Callisto, and Titus and Iapetus in orbit around Saturn. A new study suggests that, yes, it can happen.


The mere possibility of them, and their absence from where we might expect to see them "provides important clues to the formation mechanisms and histories of" solar systems.

Pasadena Astronomer Juna Kollmeier may make moon history. But Kollmeier tells Natasha Frost at Quartz that usage was just a personal choice, and that there is no official word, yet.

"IAU will have to decide!"

In their paper, the scientists settled on "submoon" for the name of their prospective discovery, but Kollmeier said she was "delighted" by other possible names, including Moonlet, Moonmoon, Moonito, Moonette, Moonlet, Grandmoon, and Metamoon. One reason is that "Moon Moon" was already a popular meme from several years ago starring a derpy wolf, which has led to some odd mash-ups. How would the moonmoon get into place? Laskow, for one, isn't voting for moonmoon. We're writing about it because these moons of moons are called "moonmoons".

Whatever comes out on top-moonmoons, grandmoons, moon-squareds, nested moons or who knows what-astronomers need to prove they exist before we call them anything.

Other reports by Iphone Fresh

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