Please consider donating to Behind the Black, by giving either a one-time contribution or a regular subscription, as outlined in the tip jar to the right or below. Your support will allow me to continue covering science and culture as I have for the past twenty years, independent and free from any outside influence.
A supercomputer simulation has shown that ice-giant planets like Uranus and Neptune can have their own dust disk during formation, thus allowing these kinds of planets to also form moons.
“So far it was believed that Uranus and Neptune are too light to form such a disk,” says the astrophysicist. Therefore, it was considered that the moons of Uranus could have formed after a cosmic collision – like our own moon, also a relatively infrequent event as the capture. Now the researchers who are also members of the NCCR PlanetS were able to refute this previous idea. Their extremely complex computer simulations reveal that in fact Uranus and Neptune were making their own gas-dust disk while they were still forming. The calculations generated icy moons in-situ, that are very similar in composition with the current Uranian satellites. From the simulations performed by the supercomputer called “Mönch” at CSCS it is clear that Neptune originally also was orbited by a Uranus-like, multiple moon system, but this must have been wiped out during the capture of Triton.
The new study has a much wider impact on moons in general, than only on our Solar System formation history. “If ice giants can also form their own satellites, that means that the population of moons in the Universe is much more abundant than previously thought,” summarizes Dr.Szulágyi.Ice giants and mini-Neptune planets are often discovered by exoplanet surveys, so this planet mass category is very frequent. “We can therefore expect many more exomoon discoveries in the next decade,” the astrophysicist says.
I actually don’t believe the assumption posited here that scientists previously believed Uranus and Neptune were too light to form disks. I think many astronomers might have believed that, while many others remained unsure, since it is more intuitive to expect such disks to form as these gas giants formed.
Either way, this computer model lends weight to those who believe the universe is littered with planets and moons, everywhere, many of which will exist in the habitable zones of all kinds of stars. These planets and moons might not have life, but they will be places we could live, when we begin colonizing interstellar space.