Solved cryptogram
The world's clocks are set by cesium, whose atoms vibrate at a rate that never varies.
Physics Facts, sourced to Royal Society of Chemistry.
What it means
Cesium was chosen because it has a single outer electron and a convenient transition frequency in the microwave range, which made it practical to build a clock around in the nineteen fifties. Every satellite navigation fix you have ever taken depends on this: the system works by comparing arrival times of signals, and an error of a millionth of a second is a position error of hundreds of meters.
The claim comes from Royal Society of Chemistry, and the page it comes from was read on 2026-08-27 to confirm it still says this.
This is not the kind of claim that goes out of date, which is why it was set as a puzzle rather than a fact with a shelf life.
Solve it yourself
This fact is a cryptogram here: 68 letters over 19 different ones, graded medium.
- SourceRoyal Society of Chemistry
- CollectionPhysics Facts
- Difficultymedium
- Length68 letters, 19 of them different
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.