Anders Celsius, who gave his name to the temperature scale, was born

On November 27, 1701, Anders Celsius was born in Uppsala, Sweden, into a family thick with professors—both his father and grandfather taught at the university where he too would hold a chair of astronomy.

Celsius spent much of his career on the sky and the shape of the Earth. He catalogued the aurora, and in 1736 joined an expedition to Lapland that helped confirm Newton’s claim that the planet is flattened at the poles.

His lasting fame, though, came from a thermometer. In 1742 he proposed a centigrade (“hundred-step”) scale with fixed points at the freezing and boiling of water—100 degrees apart.

Curiously, his original scale ran backwards: 0 for boiling, 100 for freezing.

The scale was inverted soon after his death in 1744 and later renamed in his honor. Today the Celsius degree is read on thermometers across most of the world.