بازآوایی ِ لاپلاس bâzâvâyi-ye Laplace
*Fr.: résonance de Laplace*
An → *orbital resonance* that makes
a 4:2:1 period ratio among three bodies in orbit. The
→ *Galilean satellite*s
→ *Io*, → *Europa*,
→ *Ganymede* are in the
Laplace resonance that keeps
their orbits elliptical. This interaction prevents the orbits of the satellites
from becoming perfectly circular (due to tidal interactions
with Jupiter), and therefore permits → *tidal heating*
of Io and Europa.
For every four orbits of Io, Europa orbits
twice and Ganymede orbits once. Io cannot keep one side exactly facing
Jupiter and with the varying strengths of the tides because of its
elliptical orbit, Io is stretched and twisted over short time periods. This commensurability was first
pointed out by Pierre-Simon Laplace,
→ *Laplace*; → *resonance*. |