Mercury

Mercury is the smallest planet and the closest to the Sun, a world of extremes where dawn brings three months of continuous sunshine that scorches the equator to 840°F (450°C), while sunset brings three months of frigid darkness as temperatures fall to -290°F (-180°C). It is a dead, airless world with no active volcanoes, no mountains pushing upward, no perceptible atmosphere, and no life. Craters cover its surface, most of them scars from the dawn of the solar system when asteroids and comets pounded the planet. With no air to scatter sunlight, Mercury’s sky appears black and dotted with stars even in daylight when facing away from the Sun, and Earth and its Moon can sometimes be seen as a blue speck and tiny companion. The Sun moves so slowly across Mercury’s sky that someone walking forever westward at a leisurely pace would never see it set. In the real solar system, the planets never line up as they orbit the Sun.

Washington, District of Columbia · United States