On December 21, Jupiter and Saturn will appear closer to each other than they have in nearly 400 years. This once in four lifetimes cosmic event will be visible to many–clear skies permitting–but Lowell Observatory has you covered either way.
Once every 20 years, the two largest planets in our solar system—Jupiter and Saturn—appear to meet in Earth’s skies. Such an event is called a great conjunction and the next one occurs in December. The two planets are now drawing closer to one another each night and will reach their nearest approach on the 21st, which also happens to be the night of the winter solstice and the peak of the Ursid meteor shower.
During typical great conjunctions, Jupiter and Saturn come within about one degree (the width of two full moons) of each other. But during this year’s event, the two gas giants will be only 0.1 degrees apart (1/5th the diameter of the full moon). This is the closest Jupiter and Saturn have come to each other since the great conjunction of 1623.
Speaking about the upcoming conjunction during a virtual event today, Lowell Observatory Historian Kevin Schindler highlighted just how special this event is and how lucky we are to see it. “Not since the time of Galileo in 1623 have we had one of these Great Conjunctions of Jupiter and Saturn that were this close in the sky,” said Schindler.
On the 21st, Jupiter and Saturn will look like two bright stars that are almost touching, as seen by the human eye. In binoculars or a wide-field telescope, they will still appear quite close to each other. A telescope under high magnification will reveal the cloud belts of Jupiter and the rings of Saturn, as well as several of their moons, all at the same time to form a spectacular sight.
Beginning at 7P ET on the 21st, Lowell astronomers and educators will share spectacular live views of Jupiter and Saturn through observatory telescopes while discussing the nature of conjunctions. The winter solstice also happens on the 21st and the Lowell team will explain the astronomical connection to the seasons and why they occur.