Earthlings are in for a rare treat as the two largest planets in the solar system line up for a sight that hasn’t been seen in nearly eight centuries.
And the union between Jupiter and Saturn is happening just in time for Christmas – leading to its inspiring nickname: The Christmas Star.
The Great Conjunction, as it’s also called, is really just a function of how the two planets orbit and where we are in relation to them.
“You can imagine the solar system to be a racetrack, with each of the planets as a runner in their own lane and the Earth toward the center of the stadium,” NASA astronomer Henry Throop said in a news release. “From our vantage point, we’ll be able to be to see Jupiter on the inside lane, approaching Saturn all month and finally overtaking it on December 21.”
While the two line up roughly every 20 years, the last event in 2000 was closer to the sun, so we couldn’t actually see it without specialized equipment.
That means it’s been at least 40 years since the last conjunction… but this one is even rarer than that.
The two will appear much closer together – and no human alive today has seen them this close.
In fact, the last time Jupiter and Saturn were this close together in our sky AND observable was 1226.
So, how do you see it?
The two are visible any night this week, but will be at their closest on Dec. 21, when you’ll see them in the southwest, low in the sky – about two fists above the horizon – roughly an hour after sunset.
As long as the sky’s clear and you have an unobstructed view, you can’t miss ’em.
And while you’re out, look to the southeast for a glimpse of Mars (head back out before dawn and you’ll also see Venus).
Some reports on social media suggest Jupiter and Saturn will pair up to form what appears to be a single super-bright point of light… and some on social media have even suggested this very same planetary connection some 2,000 years ago was the basis for the Star of Bethlehem.
However, that’s not quite backed up by ancient astronomical records… and the two likely won’t appear as a single object, either.
They’ll be pretty close – only 0.1 degree apart, or less than the width of a full moon – but far enough that most people will be able to make out two objects (unless you left your glasses inside, anyway).
Jupiter — already one of the brightest objects in the sky — will appear to be about 12 times brighter than its celestial neighbor, which makes sense given that it’s both larger and about 400 million miles closer.
While they will be plenty bright for the naked eye, a telescope or a decent pair of binoculars should be able to capture both in a single view.
You may even see Jupiter’s Galilean moons: Io, which has some 400 volcanos, will be slightly above Jupiter… while Callisto, which NASA believes may have a salt-water ocean sloshing beneath its surface, will be a little further above that.
Below Jupiter you may spot Europa, which some scientists believe could harbor microbial life.
Ganymede, the largest moon in the solar system (it’s about 40 percent of the size of the Earth), may be a little tougher to spot without a telescope: Rice University notes it’ll be crossing in front of Jupiter.
If you miss the conjunction this time, you won’t have to wait 800 years for the next ultra-close meeting between the two.
They’ll repeat the show in 2080.
— Walter W. Murray is a reporter for The Horn News. He is an outspoken conservative and a survival expert.