Collisions of carbon, oxygen, and nitrogen nuclei with high-speed protons would produce twice the measured ratio of boron to beryllium and only half the ratio of the isotope boron-11 to boron-10, a sibling with one fewer neutron.
Federman of the University of Toledo in Ohio and his colleagues, including Lambert, used the Goddard spectrograph to measure the relative abundances of boron-10 and boron-11 along the line of sight to three stars in the nearby interstellar medium.
The researchers conclude that the interstellar medium in Earth's neighborhood contains four times as much boron-11 as boron-10. That value, Federman adds, is similar to the ratio previously found in meteorites, which date from the formation of the solar system 4.5 billion years ago.
Kahl and his colleagues at the University of California, San Francisco, deeloped the molecular "package bomb" as a 20-sided solid with one atom of boron-10
-- a neutron-absorbing isotope of boron--at each of the molecule's 12 corners.