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The Christmas Star

This December, Jupiter and Saturn will put on a show for skygazers that hasn't been seen in roughly 800 years. Astronomers are calling it the Great Conjunction of 2020. On December 21 — coincidentally the winter solstice — the two largest planets in our solar system will appear to almost merge in Earth’s night sky.

During the event, Jupiter and Saturn will sit just 0.1 degrees apart, or a mere one-fifth the width of the Moon. The sight will likely leave many casual observers wondering "What are those large, bright objects so close together in the sky?"

In fact, Jupiter and Saturn will be so close that you will be able to fit them both in the same telescopic field of view. That’s an incredibly rare occurrence. The last time Jupiter and Saturn were this close together away from the Sun was in 1226 A.D., at a time when Genghis Khan was conquering large swaths of Asia, and Europe was still generations away from the Renaissance.

Humanity won’t have to wait quite as long to see the solar system’s two largest planets repeat this month's performance, though. Another Great Conjunction will occur in 2080. Of course, many of us alive today won’t be around then, so it would be wise to soak in this show while you can.