The two largest planets in the solar system, Jupiter and Saturn, are set to come within the range of kissing planets in the sky on Monday evening to set an intimacy that will not occur again until 2080.
This “great assemblage”, as is known to astronomers, occurs fortuitously on the winter solstice for those in the Northern Hemisphere, and early summer in the global south.
Both planets would actually be more than 730 million kilometers (400 million miles) away.
But due to their alignment with respect to the Earth, they will appear closer to each other at some point in about 400 years.
The optimal “conjugation” is scheduled to occur at 1822 GMT.
Given with a telescope or a good pair of binoculars, the two gas giants will be separated by no more than a fifth of the diameter of a full moon.
With the naked eye, they will merge into a “highly luminous” dual planet, said Florent Delefi of the Paris Observatory.
Jupiter and Saturn last closed in 1623, but weather conditions in areas where reunification could be observed were blocked.
Visibility was clearly superior that during the Middle Ages before that, on 4 March 1226 to be precise.
The best viewing conditions on Monday will be clear skies and close to the equator.
People in Western Europe and with a vast swath of Africa must train their vision in the Southwest.
“The Grand Conjunction refers to the period when two planets hold a relatively equal position with respect to Earth,” Delefi said.
Jupiter, the larger planet, takes 12 years to orbit the Sun, while Saturn takes 29 years.
Every 20 years later, they appear on Earth to observers to get close to each other.
“With a small instrument – even a small pair of binoculars – people can see the equatorial band of Jupiter and its main satellites and rings of Saturn,” Delephi said.
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