Geological evidence based on several radiometric techniques has provided a scientifically well-accepted age for the earth. represent that age of the earth as the 100-yard length of a football field, and any time interval can be represented as some distance on the field. (so something that lasted one-tenth of the age of the earth would be ten yards, and something that lasted one-half of the age of the earth would be fifty yards.) on this scale, the time from when dinosaur extinction made space for large mammals, until today, would be represented by how far on the football field?