Hacker News Reader

Let's see. 4 million pounds is around 1800 metric tons. Density of concrete is around 2 tons/m³, so 1800 tons is the mass of about 900 m³ of concrete. This is a volume of a disc about 1 m thick and 35 m in diameter. Seems plausible.

Also, from Wikipedia:

Explosive steam pressure [...] destroyed the reactor casing, tearing off and blasting the 2000-ton upper plate, to which the entire reactor assembly is fastened, through the roof of the reactor building.

https://en.wikipedia.org/wiki/Chernobyl_disaster#Experiment_...

Similarly, one is about flying in a controlled manner that is comfortable for passengers.

The other was basically a giant pipe bomb.

While I do not know if that number is correct, a Boing if engineered to be as light as possible, while the lid should be as heavy as possible.

The density of a plane is way lower than that of water, as Tom Hanks recently proved ;)

One's supposed to fly, and the other... Well the opposite I guess?