A major event is happening in the sky this month, and it’s one that won’t be matched again until 2080, according to experts.
The two largest planets in our solar system — Jupiter and Saturn — will engage in what is called a great conjunction. Astronomers use the term for the meeting of the two largest worlds, and it will be the closest Jupiter-Saturn conjunction since 1623, only 14 years after Galileo made his first telescope, EarthSky reports.
Because of the slow motion of Saturn and Jupiter — taking 30 years and 12 years to make a full circle around the sun, respectively — the conjunction is the rarest of bright-planet conjunctions.
The two massive planets will be at their closest on Dec. 21, when they will be only 0.1 degrees apart. That’s just 1/5 of a full moon diameter.
To put into perspective, extend your arm in front of you. The distance between the tip of your pinky to your first joint (near your nail bed) is about how far away the two will appear to be in the sky -- and that’s without a telescope. They will be perfectly visible to the naked eye, and will be most beautiful in the west, shortly after sunset.
The two are distinguishable because instead of “twinkling,” they both shine steadily and brightly. Though Saturn isn’t as bright at Jupiter, it’s as bright as the brightest stars, and shines with a distinct golden color, according to EarthSky.
The last time there was a great conjunction was in 2000, but the planets were near the sun and difficult to observe.
Part of the exciting news is that you can start watching them now, as they move closer and closer to one another.
The great conjunction of Jupiter and Saturn happens every 20 years, but because of the way the two planets orbit, astronomers predict the view of this year’s won’t be matched until 2080.
Will you be watching?