For the first time since the year 1226, an extremely rare phenomena will be visible in the night sky on December 21: the “Christmas Star.” The planets of Jupiter and Saturn will align so closely together that they’ll appear as one brilliant point of radiating light, creating a phenomena known as the “Star of Bethlehem” or the “Christmas Star.” Nearly 800 years ago on March 4, 1226, the same bright phenomena occurred with a close alignment of planets. Not since then has something as brilliant as the 2020 Christmas Star appeared. A similar event won’t occur again until March of 2080.
The celestial sight will unfold in the southwest sky roughly 45 minutes after sunset. In the Northern Hemisphere, the planets will be at their closest on December 21, but will be visible from December 20 to 26.
Known by astronomers as a “Great Conjunction”, the unique phenomena occurs when the sunlight reflecting off of planets in our solar system are so close together, the appearance of a giant star appears in the sky with light radiating off into four angles. While Saturn will be 10 astronomical units away from Earth and Jupiter will be 5 astronomical units away from Earth, due to their alignment in the night sky, they’ll appear to be less than the space across the Moon apart.
The peak of this phenomena arrives on December 21 which is also the winter solstice, the longest night of the year. On the winter solstice, the planets will appear just 1/10th of a degree apart, which according to NASA, is the equivalent of a dime held at an arm’s length.
The timing of the 2020 Christmas Star also has a spiritual meaning to some. According to the Bible, an unusual star appeared in a sky, leading the three wisemen to greet baby Jesus with gifts. Astronomers believe that nativity star was actually a Great Conjunction of Jupiter and Venus which occurred around 2 BC.
A Great Conjunction occurs roughly every 20 years this century, but this event is especially remarkable because of how close Jupiter and Saturn will be.
The “Christmas Star” will be visible with the naked eye, but binoculars or a telescope can aid with the viewing.