NASA’s Genesis probe, which crashed to Earth in 2004, has solved a long-standing lunar mystery.
Scientists were mystified by moon rocks brought back by Apollo astronauts, which showed the proportion of neon-22 to neon-20 increasing at greater depths inside each rock. That suggested that the sun was more active in the past, spewing out more heavy isotopes like neon-22. This ran counter to the prevailing ideas about how the sun evolved.
Now Ansgar Grimberg at the Swiss Federal Institute of Technology in Zurich and his colleagues have studied layers of a metallic glass that was exposed to the solar wind…
