Exploring the Physical World

Meeting of the Planets: Jupiter and Saturn’s Great Conjunction

On December 21, 2020, stargazers are in for a once-in-a-lifetime cosmic event: Jupiter and Saturn will appear closer together than at any time in almost 400 years, in an event known as a great conjunction. Jupiter-Saturn conjunctions happen every 20 years. But this year’s happening will be the closest the planets have come since 1623.

In this video, Ilan Manulis, Director of the Weizmann Institute’s Martin S. Kraar Observatory explains the science behind this celestial event and shares how to watch it.