Jupiter and Saturn will come closer to each other in the evening sky than they have for nearly 400 years.
The celestial event is predicted to be on Monday when the solar system’s two largest planets will appear in what is called a “great conjunction” above the horizon soon after sunset. The orbital paths of the two huge planets ensure great conjunctions every 20 years, but many are impossible to see with the naked eye because they happen during the daytime. Others are less impressive events, as the planets do not come very close together. This year’s will be the closest conjunction since 1623.
The conjunction will peak at 11.37pm Pakistan Standard Time, but the event will be visible in Pakistan from 7:26 onwards. Noting the danger of cloudy skies, astronomers point out that the pairing can be seen two days either side of the peak. The celestial event can be observed with the naked eye or with an average pair of binoculars.
Great conjunctions happen when Jupiter, which laps the sun in a shade under 12 years, and Saturn, which orbits every 29.5 years, come into near alignment with the Earth. This year, the planets will appear in the sky one-fifth of the width of a full moon apart. The event coincides with the winter solstice, when the tilt of the northern hemisphere away from the sun produces the shortest day and the longest night.
“It’s really special to have Jupiter and Saturn visible so close together,” said Dr Emily Drabek-Maunder, an astronomer at the Royal Observatory in Greenwich. “It’s something that’s nice to go out and spot.” The planets will get so close together that they may look like one very bright star. It will be 2080 before the planets align so closely again.
In the distant past, such alignments of the planets were seen as portents of things to come, from great fires and floods to the birth of Christ and the ultimate collapse of civilisation.