Have you ever gazed up at the night sky, looked up at the moon and wondered if it could have a moon of its own?

While you probably haven’t, a curious 4-year-old did back in 2015, and on Tuesday, his astronomer mom and one of her colleague’s published a paper that essentially says: Yes, a moon can have its own moon.

The Carnegie Institution of Washington’s Juna Kollmeier AKA “The Junaverse” told HuffPost that while none of the planets’ moons in our solar system currently have moons (that we know of), “Earth’s moon, one of Jupiter’s moons and two of Saturn’s moons” may all have once had moons.

But the real question is: What do you call a moon’s moon?

While Kollmeier and astronomer Sean Raymond referred to them as “submoons” in their paper, the New Scientist has dubbed them “moonmoons.”

While the International Astronomical Union is likely to have the final say, Kollmeier said they had also considered “Moonlets” and “Moons-of-Moons.”

“The internet is having a blast with the name which is A) totally unexpected, and B) super fun! People need a little fun,” Kollmeier said.

“I am not casting my vote before consulting with my son Levi. He was the inspiration for the work and if he likes moonmoon or moonito or whatever, I have to back it!”

While the pair’s findings have only scratched the surface, Kollmeier hopes that it gets both little and big kids alike “psyched about submoons.”