In 1610, Galileo Galilei aimed his telescope at Jupiter and discovered the four largest of the planet’s 95 known moons. He recognized them as...

Sunspots are relatively cool blotches on the sun’s surface (Figure 1). The number of sunspots is an indicator of how active the sun is. It has...

A fossil dig team was just finishing its last day of excavating a two-meter-long extinct fish on a private ranch in Kansas. As dusk began to settle...