Science: What is Summer?

This week, on Sept. 22, the sun reaches the autumnal equinox. At that moment in its apparent southward motion it crosses the celestial equator, stands vertically over the earth’s equator. And that moment will be heralded by many a U. S. newspaper as summer’s end. Thereupon Physicist William Warner Sleator of the University of Michigan will get mad again.

For a long time 57-year-old Professor Sleator, whose specialties are optics and spectroscopy, has bottled up his irritation when he read glib squibs about spring “beginning” on March 21, or summer “beginning” on June 21. Last week he blew the cork off with a letter to Science captioned “What is Summer?” There is no reason in nature, logic or language, declared Professor Sleator, why the seasons should be bounded by the two equinoxes and the two solstices. He wants summer to be June, July and August; autumn, September, October, November; and so on for winter and spring.

Professor Sleator: “Summer in the Saxon English which we speak by inheritance means the warm season. A dictionary definition is ‘the hottest or warmest season of the year, including June, July and August in the northern hemisphere.’ . . . Moreover, so people have written English in poetry and prose. ‘No price is set on the lavish summer, June may be had by the poorest comer.’ June, not just June 21 to 30. . . .”

The press, taking no notice of Professor Sleator’s blowoff, prepared to report summer’s demise on Sept. 22.