Air Date: Week of December 20, 1996

Facts about... the winter solstice.

Transcript

CURWOOD: In the northern hemisphere, the winter solstice is, of course, the shortest day of the year. Do you know why? Because the southern hemisphere is stealing all our light. Yes! While there are only 9 hours of daylight here in Boston, there are 13 hours of sun in Rio de Janeiro. Actually, what causes the difference in the length of the day is the earth's tilt toward the sun. The earth leans slightly on its axis like a spinning top frozen in one off-kilter position. Astronomers have even pinpointed the precise angle of the tilt; it's 23 degrees and 27 minutes off the perpendicular to the plane of or bit. As the Earth orbits the sun, the northern hemisphere goes from being angled towards the sun at the summer solstice to being angled away from the sun at the winter solstice. Because of this, we have a planet full of climate with their varying amounts of sunlight. Despite the cold we feel here in the northern hemisphere in December, the Earth is actually nearer to the sun now than it is in June, by 3 million miles.