As 2020 is coming to an end, more and more spectacular events are happening. On December 21st, Jupiter and Saturn will be aligning.
For the first time in 800 years, Jupiter and Saturn will be closer than ever. So close, in fact, that they will appear to form a singular planet in an event known as “the great conjunction”. However, this “double planet” will be bigger and brighter than it has been in the last centuries. And it is happening on the longest night of the year – the winter solstice.
How is this possible?
Every 20 years, the planets’ orbits align, and Jupiter and Saturn get really close together. According to NASA, this is because Jupiter orbits the sun every 12 years, while Saturn’s orbit happens every 30 years. Therefore, every couple of decades, Jupiter overlaps Saturn.
However, according to Patrick Hartigan, an astronomer at the Rice University in Texas “this conjunction is exceptionally rare because of how close the planets will appear to one another.” He added that “You’d have to go all the way back to just before dawn on March 4, 1226, to see a closer alignment between these objects visible in the night sky.”
So, this event is truly a once in a lifetime opportunity for outer space enthusiasts. What better gift could Mother Nature give us for Christmas other than this?
When Italian astronomer Galileo Galilei discovered, in 1610, the four moons of Jupiter, as well as the rings of Saturn, it wasn’t long (1623) before he also discovered their alignment for the first time. However, they only appear to be overlapping from Earth, as in reality, they are still hundreds of millions of kilometers apart.
This event is also often associated with the Christian nativity story, and therefore called “Star of Bethlehem” or the “Christmas Star”. The star that guides the wise men to Jesus’s birthplace. Even though it is believed to be a miracle, it might actually have a scientific explanation behind it.
However, according to Encyclopaedia Britannica, the “Star of Bethlehem” could also have been the alignment between Venus and Jupiter, as in 2BC it “would have appeared to observers in Babylon to have merged just before setting in the general direction of Bethlehem to the west”.
How to watch the phenomenon:
As reported by NASA, the conjunction will be visible after sunset, low in the Southwestern sky, as viewed from the Northern Hemisphere.
During the entire month of December, you can actually witness the planets get closer and closer together. This will be visible in the sky and you can watch it with the naked eye even leading up to the event on December 21st. They will be visible for approximately an hour after sunset.
Saturn is currently dimmer than Jupiter and can be located slightly above and to the left of Jupiter. They are easy to find in the night sky as their light is consistent, unlike stars which tend to twinkle.
Clear skies are very important for the perceptibility of this phenomenon. And it is visible from anywhere on Earth. For a clearer view, the observer is advised to use binoculars or a telescope.
Moreover, in his article, Hartigan explains that the planets won’t come so close together until after the year 2400.
So make sure not to miss it!