Solved cryptogram

Gather all the ozone that shields us from ultraviolet light and it would be a few millimeters thick.

Earth Science Facts, sourced to NOAA Chemical Sciences Laboratory.

Solve it yourself

This fact is a cryptogram here: 82 letters over 21 different ones, graded medium.

Or go to the puzzle’s own page first.

What it means

The layer is not a layer in any everyday sense. Ozone is a trace gas, a few parts per million even where it is thickest, spread through many kilometers of the stratosphere. Squeezed to sea level pressure the whole planetary supply would form a shell about three millimeters deep. That film is what absorbs the shortest ultraviolet wavelengths, which damage DNA directly, and it is why a small percentage change in it matters so much.

The claim comes from NOAA Chemical Sciences Laboratory.

Nearby in the collection

The facts either side of this one.

About as hard as this one

Scored closest to it by the model behind our guide to solving cryptograms.

Play a cryptogram

Every Earth Science Facts cryptogram · All fact collections