What would happen if one millionth of all the iron atoms on Earth turned into plutonium-239 from one day to the next?

Everybody dies.

You might think the buildings are going to explode – they won’t (if the transformation happens evenly across the planet).

The central problem will be the damned core of the Earth.

The homogeneous nature of the core should prevent major incidents from occurring. The problem will be the liquid outer core. Since it is a liquid, materials with a high density will sink.

And plutonium is pretty dense.

How much plutonium are we talking about?

The outer core has a mass of2 x1024kg. That’s a good chunk – it’s almost a third of the total mass of the Earth. There’s like3x _1025moles of iron down there… so now we have3x _1019moles of plutonium.

And they are sinking… towards the solid crust of the inner core of the earth.

Did you say it was solid? Not for much longer.

The newly forming layer of plutonium is going to experience some atomic explosions. This is going to make the earth tremble in its centers.

This will trigger several earthquakes and spectacular volcanic activity, which will liquefy the surface of the earth and kill us all.