Laura Dean Bennett
If you’re a regular star gazer, you’ve probably noticed that Jupiter and Saturn appear to have been edging closer and closer together since the beginning of December.
Even if you’re just an occasional sky-watcher, it will have been hard to miss these two “gas giants” – the two largest planets in our solar system – creeping ever closer together in the southwest sky.
Jupiter and Saturn are heading for a “conjunction,” which will occur, coincidentally, on the night of the winter solstice – the longest night of the year – December 21.
Astronomers are calling it the “Great Conjunction of 2020,” and it not only promises to be one heck of a show, but it brings to mind a great star that had a place in the original Christmas story.
A conjunction happens when, as seen from Earth, two celestial objects appear to pass close to one another.
During this event, Jupiter and Saturn will seem to actually merge together.
Not since the conjunction of Jupiter and Saturn in 1623 have these planets put on a show like this.
However, in 1623, astronomers say that, due to stargazing conditions at the time, the event likely went unseen by humans.
The last close conjunction of these two planets, that was easily observable to the naked eye, was in 1226.
“These conjunctions occur every 20 years, but this is an especially close one!” according to the NASA website.
There will be a regular conjunction of these planets on October 31, 2040, and, forty years later, in 2080, there will be another Great Conjunction.
But, of course, many of us alive today won’t be around then, so let’s try not to miss this one.
Astronomers may call it a “Great Conjunction,” but it’s also been dubbed the “Star of Bethlehem” or the “Christmas Star” because of its brilliance and the fact that it occurs so close to December 24.
Viewing conditions will depend on the weather, but look for the conjunction to shine in the southwest sky at about twilight to about an hour after sunset, when it will look like one very bright point of light.
If the evening skies are clear, the “Christmas Star” should be visible not just on December 21, but the entire fourth week of December.
And you certainly won’t need any special equipment to see it.
But if you do have a good pair of binoculars or a telescope, Jupiter and Saturn will be so close that you will be able to fit them both in the same telescopic field of view.
You could even zoom in and watch the dance of Jupiter’s four moons – Europa, Io, Callisto and Ganymede.
Then, ever so slightly shift your gaze to Saturn to observe its magnificent rings.
With or without any viewing aids, it will appear that Jupiter and Saturn are very close to each other, but, really, they are hundreds of millions of miles apart.
Having two bright planets pair up like this is extremely rare, however celestial conjunctions are fairly common.
Not to take anything away from the Great Conjunction of 2020, but there was a pretty spectacular Venus – Jupiter conjunction in August 2016.
But this “Christmas Star” conjunction of Jupiter and Saturn will be the most dramatic planetary conjunction to be seen in more than four years.
Some historians, theologians and astronomers theorize that it may have been a planetary conjunction or a comet that was called the Star of Bethlehem in Matthew’s biblical account of the nativity.
For centuries, astronomers have sifted through one theory after another – planetary conjunction? comet? supernova? – to determine what, if any, actual astronomical event was being described in the Bible.
In less than a week, as we gaze at the Jupiter-Saturn conjunction, it’s thrilling to imagine that we may be witnessing what the ancients saw as the first Christmas Star.
The Lowell Observatory in Flagstaff, Arizona, will live-stream the Great Conjunction of 2020 beginning at 7 p.m., EST Monday, December 21.