Long before we had Netflix, Hulu, and Amazon Prime Video to keep us occupied at night, humans used to delight in another form of relaxing entertainment: stargazing. And in just a few days, you’ll be able to catch a celestial show that humanity hasn’t seen in nearly 800 years.
On Dec. 21, Jupiter and Saturn will align in a position known as the great conjunction, which is the point at which they’re closest to each other in the night sky as seen from Earth. This phenomenon is often also referred to as the “Christmas star.” While this meeting happens every 20 years or so, in 2020, the planets will be closer together than they have been since 1623. But that year, the alignment was too close to the sun to view from Earth. The last time humans were able to see a great conjunction this close was in 1226, well before telescopes were invented.
This year, Jupiter and Saturn will be just a tenth of a degree apart at their closest. To help you visualize that distance, that’s about the width of a dime if you hold one out at arm’s length. (It’s worth noting that despite their apparent closeness from our vantage point, Jupiter and Saturn are actually 400 million miles apart.) As such, anyone with a pair of strong binoculars or a telescope will be able to see both planets within a single field of view. You’ll even be able to witness them with the naked eye, though the show is much more impressive at closer range.
To spot the great conjunction, look to the southwest sky just after sunset on Dec. 21. The two bright planets, which will appear consistently bright and not twinkling like stars, will be pretty low in the sky. The good news is that they’ll be viewable everywhere on the planet, so as long as the skies are clear, you’ll be good to go. If you don’t have your own binoculars or telescope, many local astronomy clubs and observatories are hosting socially distanced viewing events. You definitely won’t want to miss the show this time around; after Dec. 21, Jupiter and Saturn won’t be this close in the night sky until March 15, 2080.