听不见，不等于不存在；很多自然变化一直在低声发生
People usually trust their eyes more than their ears when they think about science. But the world is full of sounds that humans cannot hear directly. Some are too low, some are too high, and many travel through places where nobody would notice them without special tools.
New recording technology is helping researchers catch those hidden signals. Glaciers, storms, oceans, and even some machines produce waves that move through the air over long distances. When scientists translate those waves into sound or data, they can study changes that once felt invisible.
Inspired by The Washington Post reporting · Rewritten by Vocabsavvy · Vocabsavvy Original (inspired-by attribution)