十万个为什么·科学阅读30篇（4）

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为什么先看到闪电，几秒后才听到雷声？

Light travels nearly a million times faster than sound—about 300,000 km per second versus 343 m per second.
Because lightning and thunder happen simultaneously, the delay tells us how far away the storm is.
Counting seconds between flash and bang and dividing by three gives distance in kilometers.
Sound bends and scatters as it passes through varying air temperatures and wind layers, causing rumbling.
Nearby strikes produce sharp, loud cracks; distant ones sound like low, rolling booms.
Temperature gradients in the atmosphere can refract sound waves, making thunder audible farther than expected.
Mountains or buildings may echo thunder, stretching it out or creating multiple arrival points.
Thunder cannot travel through vacuum—so no sound occurs on the Moon, even during lightning-like discharges.
Meteorologists combine lightning maps with thunder timing to triangulate storm cell movement and intensity.
Wearing headphones during storms won’t mute thunder—it’s the pressure wave itself vibrating your eardrums.