A couple of years before he was due to retire from the Institute for Advanced Study in Princeton in 1944, Albert Einstein contemplated the meaning of old age. In a letter to his friend Otto Juliusburger, he wrote: “People like you and I, though mortal of course, like everyone else, do not grow old no matter how long we live. [W]e never cease to stand like curious children before the great Mystery into which we were born.”

That unrelenting quest to understand nature is the main reason why so many physicists – especially those who have spent the bulk of their lives closeted in academia – do not relish the prospect of retiring. Retirement is a bothersome event, disrupting them from getting on with the main love of their lives – physics. Many physicists therefore continue to go to the lab as if nothing has changed, and some, like Einstein, retain an office until the day they die.

As we report (see p11; print version only), Theodor Hänsch, who shared last year’s Nobel Prize for Physics at the age of 63, was equally unhappy at the prospect of having to retire from the University of Munich. According to Bavarian rules, all university staff are obliged to retire at 65. Threatening to leave for a new professorship in the US, where there is no mandatory retirement age, his university backed down and has offered to keep his job open.

But this single-minded obsession to continue with physics is not necessarily a good thing. It means that many physicists do not have a life outside the lab – no other interest can sustain them in old age. Like Einstein, many feel there is another great result just around the corner, even though their most brilliant work was done in their youth. Few ever reach those heights again, which can be hard to bear, particularly for scientists whose physical and mental well-being deteriorates in later life. (We publish an obituary of neutrino pioneer Ray Davis, who died at the end of May due to complications from Alzheimer’s disease. see p12; print version only) On a more practical level, the presence of too many retired staff can be a delicate problem for universities, which need to make space for young blood.

One solution being pioneered in the US is to build special “retirement communities” that allow academics to live alongside one another in old age – a sort of high-brow old-people’s home (see “The retirement problem”). Most have links with local institutions, and one such community – affiliated to Cornell University – has been dubbed “the best physics department in town”, being home as it was to the late Hans Bethe and other luminaries from the world of physics.

Of course, many physicists do find new activities after they retire. Some write books, take up editorial work, become consultants and even set up their own companies. Others get involved with charity work and local clubs and societies. The key thing is for physicists to prepare for retirement otherwise the transition can be traumatic. We cannot be sure, but the shock of retirement may have contributed to the untimely death of Nobel laureate Cecil Powell, who suffered a fatal heart attack just eight days after retiring from Bristol University in 1969.

But others still cling resolutely to their research when they retire. As Einstein said shortly before his death: “I’m like a run-down old car – something is wrong in every corner. But life is still worthwhile as long as I can still work.”