# Why did the person who wanted to petrify the whole world say the diameter of Earth?

Supposedly, as far as I know, the petrification device works by telling it the distance of petrification. If you say 1 meter, 1 second, it will petrify in 1 second in a radius of 1 meter. But the person who wanted to petrify the whole Earth said the diameter of Earth as distance. But if he wanted to cover the whole Earth, he should have mentioned the perimeter of Earth divided by 2, not the diameter of Earth. The diameter of Earth is smaller than the perimeter of Earth divided by 2, so you wouldnt petrify the whole Earth by saying the diameter.

Being Dr Stone a very "scientific" anime, "the most scientific anime ever", with a lot of Physics, Mathematics and Chemistry details and teachings, I wonder how can this be wrong, or I am missinterpreting something?

Why did the person who wanted to petrify the whole world say the diameter of Earth?

• Is there any reason to suggest that the petrification device is bound by Earth's surface? If the ground does not shield from its radiation, then the diameter of Earth is enough. If it does, then you can hardly hope to do it in one fell swoop. The only option I can see that makes the diameter not work and the equatiorial semicircumference yes would be as if the radiation operated like some sort of liquid that goes straight through air (and water?), but which is also bound to flow over solid ground. Dec 8, 2023 at 7:45
• @Gae.S. interesting point . Yet, people in the space station wasnt petrified during Earth's petrification. Dec 8, 2023 at 15:32
• BTW, usually kilometers of rock stop most radiation. But there are exceptions like "Neutrinos present a very high flux of particles so very intense radiation but luckily these particles interact so weakly with matter that they pass even through the Earth without interacting". Anyway, if the Space Station radiation shield can stop the petrification ray, the kilometers of rock from Earth sure also can stop it Dec 8, 2023 at 15:39
• I know absolutely nothing about Dr. STONE, but if the petrification device is located on the Earth's surface, then the space station could easily have escaped just by being on the other side of the planet. Dec 8, 2023 at 20:30
• @鬼いちゃん so you mean, because the space station would be at a distance of diameter+408 kms, it should have escaped, right? or did it get it wrong? But that would be the same for an airplane flying at diameter+10kms , wouldnt be? Dec 8, 2023 at 20:38