The days must be getting shorter, because Sun Day is fast approaching. Midway between the longest and the shortest days of the year are the equinox, when all the world stands in equilibrium—in the solar sense, at least. So in this brief time of planetary stability, the people who gave us Earth Day thought maybe the time had come for a Sun Day. Which falls, this year at least, on an actual Sunday: Sept. 21.
The idea of Sun Day itself dates back to the first president who put solar collectors on the White House roof, Jimmy Carter. In the positive wake of Earth Day, founded in 1970, the 22nd president declared May 3, 1978, as Sun Day. It didn’t quite catch on—May 3 was a Wednesday—but the intent was clear.
“Today the need to develop and expand renewable energy sources that can provide heating, cooling and power for homes, farms and factories is greater than at any other time in our Nation’s history,” Carter wrote in his 1978 proclamation. That part hasn’t changed, but the next part has: “For this reason, Americans are seeking ways of using the sun as an inexhaustible source of clean energy.”…