The Great Conjunction between Jupiter and SaturnApprox Read Time: 3 min
- For the last several days, a rare cosmic event is taking place – the Great Conjunction between Jupiter and Saturn.
- During this event, Jupiter and Saturn appear to merge in the night sky.
- The planets appeared closest to each other on the night of December 21.
About: Great Conjunction
- Astronomers use the word conjunction to describe pairing of planets and other objects in the sky.
- The term great conjunction is used to describe meetings of Jupiter and Saturn, which are two of the biggest planets in the solar system.
- The two planets align roughly after every 20 years, which is relatively rare compared to the alignments of planets closer to the Sun (and have shorter orbits).
- The current event is visible from all over the world and can be seen without any special instruments.
- From the earth’s point of view, the planets will appear very close to each other and will be separated by just 0.1 degrees. However, they are currently over 700 million kilometres apart from each other in space.
Rarity of the current event:
- The last time Jupiter and Saturn came this close together in the sky was in 1623, but the it was almost impossible to see the event, as the planets were near the sun.
- The last time the planets appeared this close and could be seen from the ground was in 1226.
- Thus, the 2020 great conjunction of Jupiter and Saturn is the closest since 1623 and the closest observable since 1226.
Duration of the current event:
- As the two planets move along their orbital paths around the Sun, they appear to be coming close to each other, since the beginning of December.
- The date the world celebrated, the night of December 21, was when Jupiter “overtook” Saturn (from Earth’s perspective).
- However, even after December 21, the planets will still appear very close together for the next few days.
- Between December 16 and 25, the distance between the two planets in the sky will appear to a viewer from Earth to be less than the diameter of a full moon.
- As the two planets roughly align every 20 years, the next two conjunctions will take place in 2040 and 2060, however, it will not be easy to view those events.
- Jupiter orbits the Sun once in 12 years, and Saturn once in 30. Thus, in 60 years (the LCM of 12 and 30), i.e. in 2080, the two planets will align at roughly the same place where they aligned on December 21, 2020 and will be much easier to see.