This is about the time that
fossil records indicate that many marine molluscs went
extinct. Donald Clayton, an astronomer at Clemson University, says the
story appears consistent: "The amount of 60Fe found in
deposits is about what you might expect from a supernova
going off about 100 light-years away." Clayton says 60Fe
would be blasted towards Earth when high energy
neutrons from the supernova core smack into iron atoms in its outer shell.