News Science Winter solstice 2020: All you should know about year's shortest day, the great conjunction

Winter solstice 2020: All you should know about year's shortest day, the great conjunction

Marking the beginning of festivals and rituals, the winter solstice, also known as the hiemal solstice or hibernal solstice occurs when one of the Earth's poles has its maximum tilt away from the Sun.

winter solstice Image Source : APUnder a midday winter solstice sun, a trio of climbers make their way up a slope on Mount Washington, Saturday, Dec. 21, 2019, in New Hampshire.

Winter Solstice, which marks the beginning of Christmas and New Year celebrations worldwide, is today! In the Northern Hemisphere, the winter solstice usually takes place between December 19 and 23. This year, it's today - December 21 (Monday). The seasonal significance of the winter solstice is in the reversal of the gradual lengthening of nights and shortening of days.

What is winter solstice? 

Marking the beginning of festivals and rituals, the winter solstice, also known as the hiemal solstice or hibernal solstice occurs when one of the Earth's poles has its maximum tilt away from the Sun. It happens twice yearly, once in each hemisphere (Northern and Southern). For that hemisphere, the winter solstice is the day with the shortest period of daylight and longest night of the year, when the Sun is at its lowest daily maximum elevation in the sky. 

The winter solstice occurs during the hemisphere's winter. In the Northern Hemisphere, this is the December solstice (usually December 21 or 22) and in the Southern Hemisphere, this is the June solstice (usually June 20 or 21). Traditionally, in many temperate regions, the winter solstice is seen as the middle of winter, but today in some countries and calendars, it is seen as the beginning of winter. In meteorology, winter is reckoned as beginning about three weeks before the winter solstice.

Solstice star: The great conjunction

Solstice star refers to the phenomenon of the 'great conjunction' or 'applause' of Jupiter and Saturn. This occurs every 20 years. Today on December 21, Jupiter and Saturn will align from our point of view on Earth and appear to be just 0.1º from each other. This is special because it marks the planets' closest encounter since the 17th century. The moment of closest conjunction is at 13:24 Universal Time.

Holidays during winter solstice

Below is the list of holidays marked worldwide, on the winter solstice day

  • Alban Arthan (Welsh)
  • Blue Christmas (holiday) (Western Christian)
  • Brumalia (Ancient Rome)
  • Dongzhi Festival (East Asia)
  • Korochun (Slavic)
  • Sanghamitta Day (Theravada Buddhism)
  • Shalako (Zuni)
  • Yaldā (Iran)
  • Yule in the Northern Hemisphere (Neopagan)
  • Ziemassvētki (ancient Latvia)
  • Midwinter Day (Antarctica)