The two planets will look like a “double planet” and provide an extraordinary amount of light. The last time these two planets aligned like this was on March 4, 1226, according to astronomer Patrick Hartigan at Rice University.
“Alignments between these two planets are rather rare, occurring once every 20 years or so, but this conjunction is exceptionally rare because of how close the planets will appear to be to one another,” he said. “You’d have to go all the way back to just before dawn on March 4, 1226, to see a closer alignment between these objects visible in the night sky.”
The spectacular sighting will be viewable from anywhere on earth.
“The planets will appear low in the western sky for about an hour after sunset as viewed from the northern hemisphere, and though they’ll be closest on December 21, you can look each evening that week,” Hartigan said. “Although the sight will be sinking toward the horizon, it will be bright enough to be viewed in at twilight. All you need is an unobstructed view to the southwest, and to look to the southwest from about 45 minutes after sunset where you are.”
Alignments like these, called “conjunctions” are not necessarily rare, but some of them are impossibly rare or only come around once in hundreds of years. Astronomers speculate that the Star of David written of in Matthew was an exceptionally rare triple conjunction among Saturn, Jupiter and Venus. One such astronomer was Johannes Kepler, one of the greatest astronomers of all time.
–Dwight Widaman | Metro Voice