The US Army has begun fielding its new Sentinel A4 radar, a next-generation sensor that is already arriving in units while a ...

Auroras, shimmering bands of light that shoot through the night sky near the Earth’s poles, can follow patterns known as arcs ...

Gravity waves have to involve a trigger. Whether it’s a mountain range or a thunderstorm updraft. It’s key that the air rises in a stable environment, so the air parcel will naturally come back down.

Concentric waves are circular ripples on water created by raindrops or other surface disturbances, visually showing how weather energy interacts with the environment.

Satellites have confirmed what mariners long suspected but could never fully prove: the open Pacific can spawn waves as tall ...

Sleep has two phases: non-rapid eye movement (NREM) and rapid eye movement (REM). It also has four stages that repeat in 4 to 6 cycles nightly. Each stage affects your body differently, from light ...