It looked awfully painful, but the burns didn't seem to bother him that much. Ray plopped his tray down and the table and listened to catch the drift of of the lunchtime conversation. Brookhaven was a wonderful place at the time. Some of the best scientists in the world worked there and many were great at spending time with grad students and postdocs.
Ray Davis was already something of a legend in the late 70s. He came to BNL in the early 50s to work on big problems. Eventually he came to work on one that was fundamental - what are the mechanisms that power stars.
Most of the energy on Earth originated in the Sun. Your lunch today was probably sunlight that left reached our planet in the past year. The gasoline in your car is older solar energy that has been stored for tens of millions of years. The core mechanism that produces this sunlight turns out to be fascinating. In the eighth grade you probably learned it is through nuclear fusion and in high school physics you may have done a simple mass to energy calculation. The real mechanism turns out to be a tad more complicated that hydrogen fusing to helium. There are several steps, but it can be roughly expressed as
Four protons (hydrogen nuclei) are burned to a single helium nucleus, two positrons (positive electrons), two electron neutrinos and some energy. The four hydrogens are a bit heavier than the helium nucleus and the positrons. The mass difference is transformed into its energy equivalent and carried off in the form of a high energy photon called a gamma ray. That energy eventually makes its way out of the Sun and radiates into space mostly in the form of visible light. A tiny bit of what leaves the sun - about a ten billionth - makes its way to the Earth.
Ray had a neat way to verify part of this - he could measure the number of neutrinos that left the Sun.
Hold up your thumb to the Sun. Every second tens of billions of solar neutrinos zip through it. They fill the space around us. How hard can it be to measure them?
This turns out to be extremely tricky business requiring enormous care in experimental design and analysis. Neutrinos were thought to be massless at the time and they interacted weakly with the forms of matter we're familiar with. A solar neutrino striking the earth has a one in a thousand billion chance of interacting with anything. Hold up your thumb and you would wait a century or so for anything to happen.
Ray's group used a 100,000 gallon tank of perchloroethylene - simple cleaning fluid which is chlorine rich). It was buried almost a mile underground in an abandoned mine in South Dakota to act as shielding from other particle reactions. If an electron neutrino with enough energy strikes a Chlorine atom, Argon-37 and an electron are produced.1
Every day about ten billion billion neutrinos would pass through Ray's tank and about two would react.
Every few weeks the tank was flushed and the Argon-37 was trapped in a charcoal filter and returned to BNL. Ray happened to have access to a gun barrel from a 16 inch WWII battleship. It was cut into a convenient eight foot, eight ton section that happened to make a dandy shield for low level radiation detection.2
Ray was very patient and very careful
The experiment went on for years and years - Ray and his group were seeing only about a third of what was expected. Either the experiment or theory were wrong. In cases like this you try to figure out just what went wrong, but the experiment was solid and the theory was very predictive and had become accepted. Everyone knew Ray was missing something.
It turns out theory was wrong - or more correctly incomplete. Twenty years later it was discovered neutrinos had a tiny mass. They weren't pure electron neutrinos, but rather an admixture of states. They would start out as electron neutrinos and during the journey to the Earth some would oscillate to the other state that was undetectable by Ray's apparatus.
Oh - Ray's burns. They were from a home repair incident. They happened all the time. He would do ordinary tasks to relax and think about other things. There were times when his mind, which was working away at something, would shift to the problem and the real world would bang into him. This certainly wasn't the only time and I'm afraid it happens to me more than I'd care to admit.
Last week I was walking down a street just before dawn. It was amazingly beautiful with a thin cloud bank forming a few feet about the ground. It wasn't more than ten feet thick. I felt my mind wandering and suddenly I knew how to work a problem that I had abandoned a month before. I find putting problems aside that require creative energy to be extremely effective - assuming you have the raw material of richly diverse experiences and connections floating about. Recently Jean and I were talking and she mentioned she sees a few levels to this and has relied on scheduling this offline creativity. Mine isn't that polished, but I require spaces where I'm not focused on current problems if I want to be creative. Thankfully my parents allowed me a great deal of freedom. Had I been scheduled to the point where I didn't boredom and freedom it is possible I would have been locked out of fields I love.
Neuroscience notes that creative bouts tend to occur when our heavily organizing frontal lobes lose a bit of control and free association in other parts of the brain lights up. Being able to partly shut down the frontal lobes may be the key to creative thought, but you wouldn't want it to take place all the time. A fascinating hypothesis that is currently being investigated is known as transient hypofrontality. Some people are very good at it. When very creative people are interviewed they all seem to have tricks to put themselves into this state where they can be highly creative. There are lots of techniques including meditation, home repair, taking long walks in nature, alcohol (more than a few writers) and other drugs, and so on.4 You find what works for you. I share walks in nature with Beethoven and Einstein although I'm not in their league. Sketching is also very effective for me along with getting lost in music. Whatever works and I'm far from an expert. Creativity is much much deeper and richer than this, but it is a fascinating idea and these practices are very common in some groups.
There is something else that is beautiful about transient hypofrontality. Neuroanatomists note the wires that connect up different regions of our brain are myelinating as we develop. It peaks in our frontal lobes in our early 40s, and then begins to unwind and demyelinate, starting at the front of the brain and working backwards.3 Our frontal lobes become poorly at conducting signals, so our ability to move the connection processes to other areas of our brain may increase after the age of 45 or so. Perhaps we can become more richly creative with age - also if you are creative, it may stick around longer than some other processes. I caution this is only a hypothesis at this point, but it may explain a lot and some of the initial experiments are promising.
In 2002 Ray Davis shared a baptism with Swedish holy water with two other physicists. A richly deserved reward.
1 Nuclear physics involves alchemy - one element can be transmuted to another. It turns out the detailed process that goes on in the Sun has a branch that produced neutrinos from the decay of Boron-8. Those are the only neutrinos in the Brookhaven experiment with enough energy to convert Chlorine to Argon)
2 Argon-37 is radioactive and has a half life of a bit more than a month.
3 Think of myelin as the insulation that shields our neural wiring. It allows signals to transmit quickly and efficiently.
4 Seymour Cray dug tunnels and built a boat every year. The boats were burned at the end of the Summer to give reason to build a new one. Of course finishing a boat was not the point of the work.
A simple avocado salad based on a recipe by Mark Bittman
Avocado Salad with Ginger Dressing.
° 85g rice vinegar
° 50g white granulated sugar
° 2 tbl minced peeled fresh ginger
° 2 avocados pitted peeled and seeded
° 75g chopped roaseted peanuts
° cilantro sprigs
° Put vinegar, suar, pinch of salt, and 2 tbl water into a small pan over medium heat Cook until the sugar dissolves
° add ginger and continue cooking until the dressing thickens - about 5 or 6 minuts.
° Remove from heat cool and cover. Let it chill at refrigerator temperatures at least an hour.
° Place a few cilantro sprigs on salad plates and overlap avocado sliceon top. Drizzle wit the ginger dressing and garnish with peanuts and a bit of a finishing salt if you like.