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Comment by double0jimb0 | Hacker News Reader

How does something like the Tzar bomb compare in terms of sound pressure? Would the immense volume of ejected material from the volcanic explosion move more air than a nuclear explosion? I'd guess lots of mass (air molecules) is just vaporized in a nuclear explosion, leaving much less mass to create pressure deltas.

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The Tsar bomb was in the ballpark of a 50 megaton explosion, whereas estimates that I've seen for Krakatoa put it at up to 200 megatons. That said, there would be differences due to the fact that h-bombs are exploded at a height to maximize the damage from the blast wave, and that a significant fraction of Krakatoa's energy would have been spent on throwing earth around. It's always hard to compare different explosions because it's difficult to know what fraction of the energy output goes into acoustic energy, but I think it's reasonable to assume that Krakatoa was louder (at least in that the sound was heard further).

That was my first thought, too. Fun facts [1]:

- its ignition was the most powerful artificial explosion in human history

- The seismic shock created by the detonation was measurable even on its third passage around the Earth

[1] http://en.wikipedia.org/wiki/Tsar_Bomba

Wikipedia says it was four times as powerful as Tzar Bomba, which would put it in the neighborhood of 200Mt. Technically Tzar Bomba was suppose to yield about 100Mt, but the scientists dialed it down a bit because they were worried about it.

Kind of crazy to think that humans made a bomb 1/4 as powerful as the Krakatoa eruption.

My understanding is that the yield was halved by the use of a lead tamper, rather than a uranium one. The tamper is a shield around the core that slows down the explosion in order to consume the reactants more fully. In production they commonly make the tamper out of waste uranium, which undergoes fission during the blast and contributes a significant amount of energy, but if you don't need the boost then lead works fine, or anything else heavy. The other thing about uranium is it greatly multiplies the radioactive fallout (fusion bombs are actually pretty clean when lead is used), which may have contributed to the decision not to use it.

"The Tsar Bomba's fireball, about 8 kilometres (5.0 mi) in diameter, was prevented from touching the ground by the shock wave, but nearly reached the 10.5 kilometres (6.5 mi) altitude of the deploying Tu-95 bomber."

I'd love to hear the pilot's thoughts on this. From what I can guess, he couldn't have traveled very far away by the time the explosion occurred. At the very least, he must have felt tremendous turbulence.

I wonder if the scientists knew how close the explosion would be to the aircraft.

The bomb had a parachute to retard it's decent in order to give them time to get away.

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