• # Question: How big of a saw would you need to saw the earth in half?

Asked by Carolina to Alex on 11 Mar 2019.
• Alexander Allen answered on 11 Mar 2019:

Ah this sort of question – the kind where you’d need infinite money and possibly do something that could end the world…

The earth is big. Let’s assume its a sphere with a radius of 6400km. This means a diameter of 12000km! Our saw would need to be bigger than that. I have taken the liberty of attaching a diagram!

The problem is that the earth is made from lots of very dense rock and you’re going to need something sharp and hard to cut through it… Lets assume we have lots of rockets capable of moving the saw up and down while taking a clean path through the earth… We’d have to make this saw out a hard rock like diamond or sapphire… Or a tough metal like Tungsten…

This is going to be expensive so can we do it cheaper?

Of course:

If we build the saw to half size we can simply slice down until we hit the core and then rotate around the earth… This will save us so much in the way of cost as the saw is half as big… I was debating this strategy when I decided that the best method would be method 3… the egg method.

The majority of the inside of the earth, below it’s crust, is liquid and this we simple need to tunnel through the crust and pull the two halves apart. The crust is only 30km thick on average so the space saw will be relatively tiny… Then we just need to attach two large powerful rockets to the Earth and pull the shell apart…

So in answer to your question… If you’re smart… A saw the size of a small county…