Saturn's Moons and Rings May Be Younger Than The Dinosaurs (space.com)

An anonymous reader quotes a report from Space.com: Some of Saturn's icy moons may have been formed after many dinosaurs roamed the Earth. New computer modeling of the Saturnian system suggests the rings and moons may be no more than 100 million years old. A new computer model suggests that the Saturnian moons Tethys, Dione and Rhea haven't seen the kinds of changes in their orbital tilts that are typical for moons that have lived in the system and interacted with other moons over long periods of time. In other words, these appear to be very young moons. "Moons are always changing their orbits. That's inevitable," Matija Cuk, principal investigator at the SETI Institute and one of the authors of the new research, said in a statement. "But that fact allows us to use computer simulations to tease out the history of Saturn's inner moons. Doing so, we find that they were most likely born during the most recent 2 percent of the planet's history."

Comments

Re:How did they calculate?

[Anonymous Coward]

Numerically. There is a family of integrators designed for integrating over long times that are stable and conserve the energy, https://en.wikipedia.org/wiki/Symplectic_integrator.

Re:How did they calculate?

[osu-neko]

In the physical literature about the n-body problem (n 3), sometimes reference is made to the impossibility of solving the n-body problem (via employing the above approach). However, care must be taken when discussing the 'impossibility' of a solution, as this refers only to the method of first integrals (compare the theorems by Abel and Galois about the impossibility of solving algebraic equations of degree five or higher by means of formulas only involving roots).

See here.