January 1, 1999

     Close to the Sun

The Earth, in its elliptical orbit, gets closest to the Sun near Jan. 4 each year. This year, it happens at 7:01 a.m. on Jan. 3.  The Earth is then said to be at perihelion, and is about 91-1/2 million miles from the Sun.  It will be farthest from the Sun, about 94-1/2 million miles, at aphelion (July 6 this year).

As Johannes Kepler discovered in the 17th century, the planets orbit around the Sun in ellipses.  As they get nearer to the Sun, they move more swiftly than when farther away because the Sun's gravitational pull is greater.  Because of this extra speed, we in the Northern Hemisphere move through winter faster than we do summer.  Summer for us is about 4-1/2 days longer than winter.

In spite of Minnesota being closest to the Sun in January, it is the coldest month of the year.  Days are warmer in the spring, summer, and fall because the Sun is higher in the sky, concentrating more heat on each acre of land.  Also, the days are longer, giving the Sun more time to heat the land and atmosphere.