As a child my father told me that after 30 the brain starts to dry out. Today, a scientific basis for this thesis appeared. Historian of science Adam Rohusen collected bibliometric data from OpenAlex and calculated an index of the most significant articles for 208 Nobel laureates (n = 1446 articles). The calculation revealed a monotonic decline in scientific activity with age, approximately linear. After 50 years a strong decline is clearly evident. The best scientists seem to do their most inventive work when they are young. Moreover, with age, one's own discoveries are quite refined, incl. with the help of subordinates. For this reason, in those days when the Nobel Prize was given for scientific discoveries, many young people were among its prize winners. After the scientific and technological revolution stopped in the 60s of the last century, the Nobel Prize began to be awarded thanks to the scientific and technological revolution, which aged together with these results, until the average age of the prize winners approached 80. Since then, the tradition of not awarding a Nobel Prize to those who have maintained at least some productivity.