'Mark your calendar--Encke's one of these has a mere 3.3-year orbital period (Halley's needs 76)'
a comet
MY SPACE: Mark your calendar--Enckes one of these has a mere 3.3-year orbital period
Mark your calendar--Encke's one of these has a mere 3.3-year orbital period
Mark your calendar--Encke's one of these has a mere 3.3-year orbital period
MY SPACE
a comet
MY SPACE