I'm pretty sure that we've all seen an atom bomb explosion by now. The mushroom cloud is engrained into the general consciousness as something that is to be feared. I'm sure we all know what an atom bomb sounds like as well, but it turns out that we don't know anything.
Thanks to some fantastic archived footage of a public atom bomb test, we can now see what an atom bomb explosion is really like. It turns out that footage involving atom bomb blasts have been doctored to include the sound of the explosion at the moment the bomb goes off. Unless you're right on top of the bomb when it goes off, that's not gonna happen.
It all comes down to the speed of light versus the speed of sound. We see the light from the explosion immediately because light travels faster than anything else on Earth. The video is taken 11km away from the explosion so it takes the sound about half a minute to reach the ears of those watching the explosion.
One other interesting thing that pop culture has convinced us is that atom bombs continue to create noise and smolder as the mushroom cloud rises. As the video clearly shows, there's an initial bang, a rush of air and then total silence as the mushroom cloud slowly rises. It's far more chilling than anything I've ever seen.
Despite how you feel about the use of atomic weapons, this is super impressive science at work. Science isn't always safe, but it commands respect nonetheless.[h/t: CNET]