December 21 marks the Winter Solstice 2025, when the Northern Hemisphere experiences the shortest day and longest night. Here's the science behind it and what it means for your region.

Looking for a sky event this week? Check out our full Sky This Week column. December 20: Io and its shadow transit Jupiter The winter solstice occurs today at 10:03 A.M. EST. This marks the beginning ...

Dec. 21 marks the darkest day of the year in the Northern Hemisphere and the start of astronomical winter, known as the winter solstice.

The Ursid meteor shower reaches its peak on the morning of December 21st, presenting an approximate rate of 10 meteors per hour from a radiant near the Little Dipper, observable under dark, moonless ...

Winter Solstice 2025 falls on December 21, marking the shortest day and longest night in the Northern Hemisphere. Learn why ...