By taking a rock (meteorite) apart atom by atom and finding out how many atoms have decayed, and knowing the rate of change (or half-life of the atom) scientists can work out how many years have passed since the rock formed.
(how many years; have passed; T:since the rock formed) (the rock; formed; ) (how many atoms; knowing; the rate of change (or half-life of the atom) Context(how many atoms knowing,List([64, 104))):(scientists; can work out; )
how many atoms knowing,List([64, 104))
how many years the rock how many atoms scientists
have passed formed knowing can work out
T:since the rock formed
the rate of change (or half-life of the atom