The ‘Great’ Conjunction of Jupiter and Saturn
In 1610, Italian astronomer Galileo pointed his telescope to the night sky, discovering the four moons of Jupiter. In that same year, Galileo also discovered a wierd oval surrounding Saturn, which later observations determined to be its rings.
In 1623, Jupiter and Saturn, traveled together across the sky. Jupiter trapped to and passed Saturn, in an astronomical event referred to as a “Great Conjunction.”
What makes this year’s spectacle so rare, then? It’s been nearly 400 years since the planets passed this on the brink of one another.
The closest alignment will appear just a tenth of a degree apart and last for a couple of days. On the 21st, they're going to appear so close that a pinkie finger at arm’s length will easily cover both planets within the sky. The planets are going to be easy to ascertain with the unaided eye by looking toward the southwest just after sunset.
From our viewpoint on Earth the large gas giants will appear very approximate , but they're going to remain many many miles apart in space. And while the conjunction is occurring on an equivalent day because the solstice , the timing is simply a coincidence, supported the orbits of the planets and therefore the tilt of the Earth.