Beryllium-10 can be produced in the Sun when highly energetic protons bombard the nuclei of other elements like carbon and oxygen.

BBC: Apollo samples reveal Moon's origin

Reducing the number of beryllium ions in the trap will boost the sensitivity further, the researchers say, and, with a single beryllium ion, it should be possible to measure a single yoctonewton.

ECONOMIST: Scientists measure a few yoctonewtons for the first time

But, a detailed analysis of the lunar samples by Kuni Nishiizumi, from the University of California at Berkeley, and Marc Caffee, from Purdue University, suggests that far more beryllium exists in the soil than can be accounted for by cosmic-ray delivery alone.

BBC: Apollo samples reveal Moon's origin