All you want to know about the ‘Great Conjunction’

About 30 minutes after the local sunset, in the southwestern direction, low in the sky, two giant gas plants, Saturn and Jupiter will appear so close that we will not be able to distinguish them apart. The last time Jupiter and Saturn were this near was on July 16, 1623. The next time they will come again this close will take place only in 2080.

The inclination of the orbits of the planets around the Sun is more or less the same. Therefore, the five visible planets, Mercury, Venus, Mars, Jupiter, Saturn and the Moon, appear to follow the same path that the Sun takes in the sky. As athletes run along the track, one whose speed is higher catch up the slower one from behind. Likewise, as the speed at which one planet appears to move in the sky are not same, once in a while, the fast-moving one will catch up with the relatively slow-moving planet in the sky. Such events are called ‘conjunction’. When the jumbo planets, Jupiter and Saturn come close to each other, it is called as ‘Great Conjunction’.

Jupiter and Saturn, which takes 11.86 years and 29.4 years, respectively to go around the Sun. Therefore, every 19.85 years they are aligned in a straight line with Earth, resulting in great conjunction. Likewise, other planets also produce periodic conjunction as they orbit Sun. For example, next year, on July 13, 2021, a conjunction of Venus and Mars will take place.