In Catch-22, Airman Dunbar spends all his free time with people he doesn’t like. That makes time go by slower so he can enjoy life longer.
Physicists have their own way of slowing time. Moving clocks tick slower than ones at rest. Not because something goes wrong with the mechanism of a moving clock, but rather the passage of time itself slows down. This effect, called “time dilation” is sufficiently familiar that the writers used it in joke by Leonard about a double-date that couldn’t end soon enough: “Approaching the speed of light doesn’t slow down time. Approaching them does.”
It is tempting to use this as a launching point to discuss how a little-known patent clerk in Switzerland spent all his free time in 1905 thinking about physics problems (there was no internet or video games) and predicted all this. That was Einstein and this was his special theory of relativity. Normally, I love teaching special relativity. I especially love teaching it to freshmen since so little math is required: just distance equals rate times time and how a right-triangle works. Yet, I won’t do it here because it really isn’t because of the theory of relativity that we believe time goes slower for moving objects. True, the theory of relativity is beautiful and Einstein was a one of the smartest guys ever. But physics departments’ trash cans are full of beautiful theories and many brilliant people are long forgotten. The real reason we believe in time dilation is because experiments say it is so. It is better to delve into one of them.
Particle accelerators (a.k.a. atom smashers) are great places to find things moving near the speed of light. In the 1990’s I worked at the world’s largest particle accelerator, an international scientific laboratory called CERN, as a “post-doc”. (A post-doc is the few years in a physicist’s life just after receiving a doctorate but before taking on a permanent post. Although it has never been stated in the show, I think Leonard, Sheldon and Raj are all post-docs.) While I was working at CERN, my friends and I needed particles to test and align our detector. The accelerator division kindly sent us a beam of particles called muons. Muons are just like electrons but they are heavy and undergo radioactive decay quickly, living on average for only 2.2 millionths of a second (0.0000022 seconds). Even though these muons moved at nearly the speed of light, even light traverses only 2200 feet in 2.2 millionths of a second. You might think that when being sent from one side of the (large) lab to the other, you would lose most of them to decay before they arrived. Yet, “time dilation” came to our rescue. The muons we needed to calibrate our detector moved at 99.9999% the speed of light and we saw their internal clocks slow down by a factor of 1000, meaning they lived 1000 times longer. It was no problem to bring them a safe, long distance from the accelerator, down to our experiment, where we made good use of them.
If you could ask them, what would the muons say happened? They likely would say that they were are at rest the whole time and rather it was me, my friends,and the whole lab moving towards them at 99.9999% the speed of light. They are not moving so they would still measure their own average life as 2.2 millionths of a second; so how did they get across the lab to our detector without decaying? If asked, the muons would report the distance across the lab to our experiment was 1000 times shorter than we would. Moving near light speeds, moving objects become much shorter. Such “length contraction” is an experimental fact. While the muons and I may have disagreed why they reached my experiment without decaying, we both agree on the important part: They did.
Could speed be the secret to Dunbar’s quest for longevity? Can physicists make fountain of youth by the slowing down time with speed? Yes…but there’s a catch. Even if we put you on a fast rocket ship, since time slows down, your metabolic rate slows as well. Everything around you undergoes the same slower passage of time as witnessed by the rest of us. So Leonard has it exactly right. He would experience time unfolding just as if he were at rest. In fact, Leonard could well say that he really is the one at rest and it is everyone else that is moving.
That’s some catch, that Catch-0.0000022 .