Frankenstein moon: what hides Triton
Astronomers have long suspected that the huge moon Triton is actually a “newcomer” that invaded Neptune’s orbit. Recently, they finally managed to calculate how the other moons of this planet looked before the invasion of their fellow. All other gas giants of the solar system (Jupiter, Saturn and Uranus) have similar lunar systems. In each of them, the mass of the planet is approximately 10, 000 times the mass of the moon. For the most part, every planet has several small moons orbiting in the same direction as it.
However, Neptune is different from its relatives. Its lunar system consists of several tiny moons that either spin extremely close, or are spaced long distances. In addition, there is a huge Triton, which also rotates in the opposite direction. Is it weird? Sure!
Elephant in a china shop
Robin Kanup at the Southwestern Research Institute in Colorado and Raluka Rufu at the Weizmann Institute of Science in Israel used a series of computer simulations to figure out what the Neptune lunar system looked like before Triton appeared in it. Initially, as it turned out, it was similar to the similar system of Uranus - but this did not last long. "Triton figuratively and literally" broke "into the orbit of Neptune and introduced chaos into a well-organized system of moons, " explains Kanul.
In order for a system like the moons of Uranus to become what astronomers today observe in the orbit of Neptune, three important factors must be present. First, the young moons were not supposed to destroy Triton at the time of the collision. Secondly, they had to slow down Triton in the process so that it fell into a circular orbit, which it rotates to this day. Finally, thirdly, the outer moons of Neptune were supposed to remain intact.
“The question is, how exactly did the planet manage to capture Triton in an oblong orbit, and then“ translate ”it into a round one? To do this, you need to dissipate some of the moon’s energy to slow it down, ”notes Scott Sheppard of the Carnegie Science Institute in Washington.
Kanul and Rufu discovered that Triton's gravity literally scattered smaller moons to the sides. He nevertheless ran into some of them and, having received the necessary slowdown in the end, changed the orbit to circular. This process took place quickly enough so that the moon itself did not fly out of inertia beyond the planet's gravity, so that it did not touch the outer orbital region and did not affect the moons that rotate away from Neptune.
The Frankenstein Monster in Space
Unfortunately, it will be difficult to confirm this hypothesis even if we send a satellite to Triton. It is covered with cryogenic melting ice: in places the ice melts and freezes again, which is why the entire cover of the planet is in constant motion and all traces of Triton’s collision with other moons have long been erased.
On the other hand, if scientists succeed in taking samples of the planet’s soil, everything will immediately become clear. Triton is a moon molded from fragments of the original celestial body and pieces of those moons that it crushed at the entrance to the orbit of Neptune. Astronomers jokingly compare it with the Frankenstein monster - who knows, maybe such an unusual nature actually carries a lot of secrets?