GRAND RAPIDS, Mich. (WOOD) — The winter solstice will mark the start of astronomical winter this week. 

Meteorological winter began on Dec. 1, but the new astronomical season will begin on Dec. 21.

The seasons are caused by the tilt of the earth and how it orbits around the sun. At the time of the winter solstice, the Northern Hemisphere is tilted as far away from the sun as possible. 

The winter solstice is the day with the least daylight hours and the most nighttime hours in the Northern Hemisphere. All areas north of the equator receive less than 12 hours of daylight. After the solstice, we’ll start gaining daylight hours back. 

A meteor shower will peak the morning after the solstice. The Ursid meteor shower has been active since mid-December, and the peak will arrive on Dec. 22. The bright waning gibbous moon may make it difficult to see the meteors. 

At best, the Ursid meteor shower normally produces about five to 10 meteors per hour, so it is not the most vibrant shower. Still, if you want to test your luck, get away from city lights after 1 a.m. and look up. 

As the month of December comes to an end, try to spot Mercury. It will be in a line with Jupiter and Saturn in the evening, just to the left of Venus. Look to the southwest after dark to see the four planets, and bring binoculars if you have them.