Solved cryptogram
Helium is light enough to escape Earth's gravity, so the supply in our air keeps leaking away.
Chemistry Facts, sourced to Royal Society of Chemistry.
What it means
A helium atom at the top of the atmosphere moves fast enough to reach escape velocity, and once it is gone it does not come back. That makes helium the one element on Earth that is genuinely being lost. What we use is dug out of the ground, where it has been accumulating for hundreds of millions of years as heavy elements decay, and it cannot be manufactured at any useful rate.
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This is not the kind of claim that goes out of date, which is why it was set as a puzzle rather than a fact with a shelf life.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: 75 letters over 19 different ones, graded medium.
- SourceRoyal Society of Chemistry
- CollectionChemistry Facts
- Difficultymedium
- Length75 letters, 19 of them different
Nearby in the collection
The facts either side of this one.
- Royal Society of Chemistrymedium, 73 letters
- Royal Society of Chemistrymedium, 70 letters
- Royal Society of Chemistryeasy, 74 letters
- Royal Society of Chemistrymedium, 73 letters
About as hard as this one
Scored closest to it by the model behind our guide to solving cryptograms.
- Royal Society of Chemistrymedium, 71 letters
- Royal Society of Chemistrymedium, 75 letters
- Royal Society of Chemistrymedium, 77 letters
- Royal Society of Chemistrymedium, 74 letters