It had not happened for more than 800 years, so we advise to write this event on the agenda so as not to lose sight of it: the mighty Jupiter and the planet of the rings, Saturn, will be seen as a double planet for the first time since the Middle Ages. .
Although planetary alignments are in themselves quite rare to observe, this is even more so because of the closeness to which both planets will be seen. We would have to travel until March 4, 1226 to see an identical scene of proximity between the two planets in the night sky.
Just after sunset on the night of December 21, 2020, both worlds appear closer together in the night sky than they have ever been (at least not since the Middle Ages): at their closest point, they will be just 0.1 degrees away (barely 1/5 the diameter of a full moon), offering astronomers an unrivaled opportunity to welcome the winter solstice in the northern hemisphere and the summer solstice in the northern hemisphere. southern hemisphere (it is the longest night of the year in the northern hemisphere and the shortest in the southern hemisphere).
“On the night of closest approach, on December 21, they will be seen as a double planet, separated by only 1/5 of the diameter of the full moon”, comments astronomer Patrick Hartigan of Rice University in Houston, Texas (USA). USA). “For most telescope viewers, each planet and several of its largest moons will be visible in the same field of view that night.”
Where can it be seen from?
We can contemplate this planetary conjunction, in which the two planets, Jupiter and Saturn, will be seen next to each other, from anywhere on the planet. This incredibly close conjunction of Jupiter-Saturn in 2020 will not occur again until March 15, 2080, so we advise you not even to wait until December to start seeing this close-up (or if you do, observe between March 16 and December 25, which is when they will be closest at this beginning of the solstice).
Logically, the planets will not be physically close to each other, but from our vantage point, planet Earth, they will appear practically a single point of bright light to anyone looking up into the night sky. If the sky is clear, the planetary alignment should be visible from almost anywhere on Earth, about an hour after sunset, although the best viewing conditions will be near the equator.
“The further north a viewer is, the less time they have to glimpse the conjunction before the planets sink below the horizon,” Hartigan says.
How to recognize them?
It is easy. Jupiter is brighter than any star; Saturn is not as sparkling as Jupiter, but it is as bright as the brightest and glows with a distinctly golden color. Unlike twinkling stars, Jupiter and Saturn shine constantly.
