Mathematicians Of The Day
Quotation of the day
From Johannes Kepler
On how the motion of a planet defines its sphere:
... and thus it comes about gradually by the linking and accumulation of a great many revolutions that a kind of concave sphere is displayed, having the same center as the Sun, just as by a great many circles of silken thread, linked with each other and wound together, the dwelling of a silkworm is made.