Everyone knows that Fourth of July means the night sky will be filled with the colorful (and loud) fireworks. But all those sparks, which take different shapes and color as they explode in the air, ...

BOOM! What was the earth-shaking, jolt-you-awake, set-off-the-car-alarm sound? Oh right, a rocket launch. But why are some rocket launches accompanied by sonic booms and others aren’t? Either way, ...