The outermost layer of the Earth is called the crust, and it's surprisingly thin compared to the other layers. Here's a breakdown:

* Continental crust: Ranges from 30 to 50 kilometers (19 to 31 miles) thick.

* Oceanic crust: Ranges from 5 to 10 kilometers (3 to 6 miles) thick.

So, the Earth's crust is only about 0.5% of the Earth's radius. To put that into perspective, if you were to shrink the Earth to the size of a basketball, the crust would be about as thick as the paint on the ball.