Name: Scott Tiefel
I heard that Halley's comet orbits the Sun in regular cycles. How do we
figure out the cycle of comets?
When a comet is first discovered, its orbital elements are computed from
successive observations. These tell us what kind of orbit (around the Sun)
that the comet has: it can be elliptical, parabolic, or hyperbolic. Only
comets with elliptical orbits are periodic. The reason that all comets are
not periodic is because some have their orbits perturbed by the gravity of
the outer planets, especially Jupiter. In addition, comets can breakup due
to a close encounter with the Sun.
Click here to return to the Astronomy Archives
Update: June 2012