“Search me, O God, and know my heart; test me and know my anxious thoughts.” Psalm 139:23 (NLT)

Towering above the landscape, a volcano often appears peaceful. Its slopes may be covered with forests, flowers, or even small villages. Birds nest on its sides. Tourists snap photographs. From a distance, everything seems calm and stable.

Yet deep beneath the surface, something unseen may be happening. Pressure builds. Molten rock churns. Gases collect. The mountain looks quiet, but hidden forces...

The surface of the moon is a strange place. It is covered with gray dust, jagged rocks, deep craters, and silent plains stretching for miles. There is no wind to move the dust. No rain to wash away footprints. No flowing water to reshape the landscape. Scientists tell us that footprints left by astronauts during the Apollo missions may remain there for millions of years because nothing exists to erase them.

When Neil Armstrong stepped onto the moon on July 20, 1969, he left more than a...

The planet Mercury races around the sun faster than any other planet in the solar system. A single year on Mercury lasts only eighty-eight Earth days. It moves at incredible speed, yet despite being closest to the sun, Mercury is not the hottest planet. During the day, temperatures can rise above 800 degrees, but at night they plunge hundreds of degrees below zero. One side burns while the other freezes. Scientists say Mercury has almost no atmosphere to hold in heat or provide protection...