Lucretius atoms are increasingly visible to the artificial eye

For Lucretius, the “primordia rerum”, i.e. the principles at the basis of natural reality which are the atoms, were a logical foundation that made it possible to fully interpret the physical world, and at the same time to eliminate superstitions and fears from the mind of man. Millennia later, and decades after my university studies, we have reached such a level of technical perfection that, thanks to atomic force spectroscopy, or even more advanced techniques such as electron pticography, we can get pictures of individual atoms and how they are bonded together – the shape of the famous “concilia”, the way Lucretius called the groupings of atoms that we know today as molecules, are literally before our eyes. As these results were documented in the scientific literature, the dashes and formula symbols I had found in my books became a physical picture of reality; and, although we already had proof that this should be the case, the sense of astonished amazement in observing the shape of the molecules that I found described by ink alone on my university pages become an image of physical reality, is one of the things I’m grateful for that I lived in this, and not other eras.

Seeing the physical images of aromatic polycycles, distinguishing single bonds from double bonds in the images obtained and so on, represents the opposite extreme to what we have reached with the Webb Space Telescope: pointing our instruments into the depths of space, we observe very distant objects and gigantic, at the beginning of time, and looking at the images obtained with the aforementioned techniques we arrive at the minute structure of reality, here and now. Well, new work has expanded our view at molecular resolution: no longer just the shape of the molecules, but their very chemical nature can be captured in images obtained by combining tunneling effect microscopy with an X-ray synchrotron light source, a group of scientists has managed to obtain images of individual atoms by differentiating not only their shape, but also their chemical nature. I’ll try to explain briefly what this means.

In the chemical formulas we are familiar with, the chemical bonds between atoms are represented by dashes, while the nature of the bonded atoms is represented by their atomic symbol (for example, H for hydrogen and O for oxygen in the formula for water). Until today, with the amazing techniques mentioned above, we have obtained images of the shape of molecules: dots, corresponding to atoms, joined together by more elongated and thinner areas, corresponding to chemical bonds, to draw a precise structure. However, which atoms were bonded to each other was not possible to deduce from the images obtained: the image of a molecule of three atoms joined together could be water (two hydrogens and one oxygen), or for example ozone (three oxygen atoms). Well, exploiting the fact that each type of atom, when illuminated by the X-rays of the synchrotron light used, gives a different type of signal, and illuminating the sample under examination with this source as its disposition is detected with the usual techniques of the atoms in the molecular structure, one atom at a time, the researchers in their work demonstrate how it is possible to reconstruct together the position of the atoms, their bonds and the chemical nature of each of them.

With this step, those arid little formulas on the pages of our textbooks have truly become visible in a single “real” image: each atom can be colored differently, depending on the type, just as was done previously when the molecules were drawn to the computer, so that there is no longer any separation between the way in which we have represented each chemical structure up to now, and the direct image that we can obtain starting from a physical sample. Anyone who does not directly appreciate the beauty of this scientific result from a purely intellectual point of view will perhaps still be satisfied in knowing that this goal is also extremely interesting from an application point of view. In fact, imagine having to determine the nature of an active ingredient of natural origin, which has proved to be useful, for example, in fighting a bacterium resistant to the available antibiotics. This step is indispensable, because in order to produce a new drug on a large scale and with the necessary purity, it is first of all necessary to precisely know its chemical structure, and then to devise a suitable synthetic procedure to obtain the desired product.

Today, the first of these steps is accomplished using spectroscopic techniques of various kinds, i.e. by reconstructing the desired chemical formula from a set of chemical-physical properties that the compound under examination possesses. In the future, if the new results become widely applicable, they will no longer be needed: similarly to the way we take a photo to get the detailed image of a macroscopic object, we will capture a direct image of what interests uswithout needing anything else. Our artificial vision, for the first time, captures the shape and nature of atoms and entire molecules; and who knows what Lucretius would have thought, when he could register with his eyes (the preferred method of the Epicureans) that the reality of things was exactly what he and all the followers of Epicurus anticipated, millennia ago.