To understand whether it is possible to photograph the structure of the atom, it is necessary to find out what the atom itself is. Everyone has at least once seen a picture, which usually depicts the structure of the atom.

In its center is the nucleus (the so-called nucleon – protons and neutrons, connected by a strong interaction between them), and around the nucleus orbitals of electrons spin. But this scheme is often misleading: the orbitals are shown as thin lines, and the electrons act as particles. All this resembles the motion of cosmic bodies in orbits. But in fact, this diagram conveys only the general features of the structure of the atom.

Let’s imagine that we were able to photograph a hydrogen atom, which has only one electron, at a certain point in time.

The yellow dot is the nucleus and the blue dot is the electron. Let’s remember its location and take a picture of the atom at a different point in time.

The electron has changed its location, which makes sense. But what happens if we take several dozen such pictures and overlay them on top of each other? So the electron can be almost anywhere in the atom? True, but if you look closely, you will find that it is more likely to be found in a certain circle (highlighted in gray) than in other places. It is this area that is called the “orbital,” and the entire area in which an electron can be found would be called the “electron cloud.”

Did you say probability? Why is it impossible to calculate the exact location of an electron in an atom? Here we should remember that the electron is an elementary particle, and can behave as a particle in a certain situation and as a wave in another situation. That is, its location in the atom is given by the probability distribution.

When the atom is unaffected, the electron behaves like a wave, but just look at it and it becomes a particle and appears to us at a point where it should not be at all. That is, at any attempt to photograph the structure of the atom, the whole system collapses, and we cannot see the electron in its actual state.

It turns out that it is impossible to photograph the real state of the atom? There is a solution to the problem and it is similar to what we did in the diagram above. That is, we recorded the position of the electron around the nucleus at different moments of time and then superimposed the pictures on each other. It turns out that the electron is sort of everywhere in the electron cloud, but at the same time it’s not at any particular point.

Of course, there is no such camera that can photograph the structure of the atom at a certain point in time, so scientists and the Center for Elementary Particle Research, had to act by other methods.

To simplify the experiment, the hydrogen atom was chosen, as it contains only one electron. Next, the atom was placed in a sealed chamber between two lasers, which, by ionizing the atom, forced the electron to jump off its orbital. The electromagnetic field inside the chamber directed the electron toward the detector plate, where it was marked as a dot. In doing so, its position on the plate coincided with the position it occupied in the atom at the moment of firing. By repeating the experiment about two thousand times, physicists got a picture that can be considered a representation of the structure of the hydrogen atom. The redder the dot, the more likely the electron was to be there.