the.com/janus and epimetheus
two moons of saturn stuck in an orbital tango, swapping lanes every four years so neither one crashes.
means janus and epimetheus are co-orbital moons of saturn locked in a rare gravitational dance where they periodically trade orbits instead of colliding.
from named after the mythological doorkeeper god janus, who looks both ways at once, and his brother epimetheus, whose name means afterthought, fitting since he was discovered second yet named for a figure known for thinking too late.
orbit swapthey trade orbital paths roughly every four years
closest gaponly about 50 kilometers separate their orbits
discovery mixupastronomers first thought they were one single moon
shapeboth are lumpy potato shaped, not round
for instance
orbital resonance models — used by physicists to study horseshoe orbit dynamics elsewhere