The term "solstice" comes from a Latin word meaning, "the point at which the sun stands still." The summer solstice is the astronomical moment in time when the sun is directly overhead its northernmost point on the globe -- the Tropic of Cancer (23.44° north of the equator). Summer begins today with the solstice occurring at 23:09 UTC (7:09 p.m. EDT).
Beginning tomorrow and continuing until December's winter solstice, the sun will be directly overhead points further and further south.
The constant 23.5° tilt of the earth's axis is what causes us to have seasons. Because the Northern Hemisphere is currently tilted toward the sun, that means we are getting more daylight at this time of year -- more than 14 hours in most of the United States. It also means that the sun's radiation is at its most intense, making today the day you are most at risk of burning the quickest.
Learn more about seasons and the sun with these Science NetLinks resources:
- Cooler in the Shadows (K-2)
- Weather 2: What's the Season? (K-2)
- Looking at the Night Sky (3-5)
- The Four Seasons (6-8)
- Measuring Shadows (6-8)
- The Sun (6-8)
- Tilted Earth (6-12)
- USA Today's Weather Basics (6-12)
- Star Power! Discovering the Power of Sunlight (9-12)
- Summer Science Fun (K-12)
Photo Credit: Clipart.com