It’s another trip around the sun for two major players in our solar system, but the path they are charting will make for impressive and historic viewing experience for stargazers and professional astronomers.

Every twenty years Jupiter passes Saturn on its way around the sun, causing them to appear close in the sky – an event known as the Great Conjunction. What makes this a particularly momentous occasion? Proximity, explains Trent University Physics & Astronomy professor, Dr. David Patton.

“This Conjunction is unusually close. It is about 800 years or so since they have been so close together in the night sky,” explains Professor Patton, who goes on to explain how astronomers were able to predict the timing of The Great Conjunction.

“We understand the orbits of the planets really well, they move in a very predictable fashion. […] They are subject to the force of gravity which we understand well. With that methodology, astronomers have been able to predict today’s events and it is happening right on cue.”