Glenn Seaborg: Dedication of the Chemistry Building

Part 4/9

Nuclear chemistry and spectroscopy can find other unexpected applications, too. The fields of archaeology and the history of art have profited here at Brookhaven as well, because of the imaginative use of nuclear techniques, especially neutron activation, to make highly sensitive but non-destructive chemical analyses of irreplaceably unique works of ancient art. This can make, at times, for a kind of detective story with clues thousands of years old! This story has been told before but is still worth repeating. Pieces of pottery made in the ancient city of Arezzo, Italy, were very popular in the Roman Empire because of the high quality of their workmanship. The potters even marked their ware in the same way that manufacturers trademark their goods today. Yet, by means of neutron activation analysis, it has now been possible to show that much of this ancient pottery must have been made elsewhere and given a false trademark, since the chemical composition of the clay is sufficiently distinct to clearly establish that it was made in Arezzo.

Examining the pottery. From left: G.Tape, J. Bigeleisen, G. Seaborg, unidentified, R. Dodson. Smoking was obviously permitted in those days.

One of the prevalent, but erroneous, images, of the chemist in the popular eye is that of a relatively obscure and unimaginative fellow who never gets very far away from his test tubes, either in thought or in person. It may be that with such a beautiful new building such as this, few chemists at Brookhaven will want to wander, whether in body or spirit. There is no question, however, that their creative imagination will continue to wander on a truly cosmic scale, since they are using highly sensitive nuclear techniques to learn more about the solar system and our universe of matter and energy.

It is all too easy for all of us to take our material world for granted. What we sometimes need is the enhanced sense of wonder that children and deeply inspired adults seem to possess. It is a pity that so many of us lose this sense of wonder as we get older, because the universe is really a most remarkable place. When we see things every day, after a while we get to the point where we never really look at them critically any more. We are only impressed by rarities or freaks. The fact that hydrogen, oxygen, and silicon are common kinds of atoms, and rhenium and platinum are very scarce, is, to the eye of the thoughtful scientist, as remarkable as the existence of comets or dinosaurs or giraffes. Certainly, these atoms are just as important a matter for scientific study and understanding. The relative proportions and distributions of the elements and of their various stable and unstable isotopes is, after all, merely a reflection of the nuclear properties and behavior of these different kinds of atoms and nuclei, at the time they were first formed in the universe billions of years ago and of some of their history since that time.

Among the most sensitive tools of modern science are the mass spectrometer and radiation counters. In the skilled hands of chemists here at Brookhaven, they tell much of the ancient and recent history of the universe. For instance, meteorites can serve as a unique kind of space-probe reporting on chemical and physical conditions elsewhere than on our own limited planet, and in this moment of time. Meteorites are the only material samples we have yet obtained from other parts of our solar system, so their study continues to be significant. Many meteorites are older than the oldest rocks on the surface of the earth, so their history is unique. In addition, meteorites in space are constantly exposed to highly energetic cosmic rays. When this happens, new atomic fragments, both stable and unstable, are produced. Using highly sensitive analytical techniques, scientists here in this laboratory can count and identify these fragments, and correlate these experiments with the results of bombardments of similar samples in the high-energy accelerators. When these results were interpreted, unexpected new things were discovered about radiations in space. For example, scientists already knew about the so-called "solar wind," which is a very thin plasma, or steady stream of small but fast-moving atomic particles, streaming out in all directions from our sun. Isotopic measurements here have showed that this solar wind serves to deflect, and so partially to shield the earth from high-energy cosmic rays from the depths of remote outer space.

Last Modified: January 31, 2008