Many religious and cultural traditions celebrated the rebirth of sunlight after this dark period. In the northern hemisphere, passing the winter solstice meant the return of the sun, which seemed to be disappearing. For our distant ancestors, dependent on hunting, gathering, and growing, the seasons and the weather played a central role in their lives. People from many different cultures have held solstice celebrations for thousands of years. (Again, everything is reversed if you live below the equator.)Įven stranger, Earth is closest to the sun between January 3 and 5, but since the northern hemisphere is tilted away from the sun, the nights are long and the weather is cold. So the coldest days usually happen in January and February. (Have you ever gone swimming off Cape Cod in June? Brrrr!) Similarly, the oceans hold onto the warmth of summer long after the barbeques have ended. In June, they are still cool from the winter, so the warmest days happen in July and August. Oceans take a long time to heat up and cool down (something called thermal inertia). Reasons for Seasonsīut then why, if the solstice is the turning point, is June 21st considered the first day of summer and December 21st the first day of winter? This odd fact is because while the hours of daylight are changing, the oceans need to catch up. The word solstice, in fact, comes from the Latin for sun + to stand still. At the solstice itself, however, the sun appears to stand still in the sky for a few days before and after. The solstice marks the turning point, when the days begin to grow longer (in the winter) or when they begin to grow shorter (in the summer). So if you live in the northern hemisphere (north of the equator), Earth is tilted toward the sun in the summer and away from the sun in the winter. So at different times of the year, either the northern or the southern hemisphere is tilted toward and is therefore closer to the sun. In fact, it's tilted just about 23.5 degrees. It does not complete this trip, however, with the North Pole at the top and the South Pole at the bottom because Earth is tilted. In the course of one year, Earth orbits around the sun. And in the winter, December 21 or 22 is the winter solstice, or shortest day.īut wait! If you live in Australia, you experience the opposite-the longest day is in December and the shortest is in June. In the summer, around June 20 or 21, we experience the summer solstice, which is the longest day of the year. EDT (04:34 UT*) by Karen Barss Related Linksĭid you ever wonder why the days are so long in the summer and so short in the winter? The length changes throughout the year.
0 Comments
Leave a Reply. |