The Earth Squeezed Into a Wire

If the Earth were squeezed into a wire the thickness of a human hair, how long would it be? A lot longer than it seems!

There are multiple ways to calculate this and below I’ll just go with the simplest and most obvious.

However keep in mind: different materials expand and compress differently depending on temperature and pressure, so here we’re just assuming standard conditions so it’s obviously a little naive but that’s okay this still gives us a good order of magnitude.

The Earth Volume Method #

So how thick is a human hair? 70 microns in diameter.

The section of a human hair has an area of π × r² = π × (70/2)² = 3,848µm².

The volume of 1km of human hair is π × r² × h = 3,848 × 1,000,000,000 = 3,848,000,000,000µm³. Lets convert this to cubic kilometers, that yields 3.848 × 10^-15 km³.

The Earth is about 1 trillion cubic kilometers.

So how many kilometers of human hair does the Earth’s volume fit into?

10¹² / 3.848 × 10^-15 = 2.5987526 × 10²⁶ km

How long is that really? Well the observable universe is 8.8 × 10²³ km in diameter.

So if we could squeeze the Earth into a wire the thickness of a human hair, it would be 295x longer than the observable universe.