When there is something wrong with a person and doctors are unable to see what it is just by looking from the outside, an MRI scanner can prove useful. This machine uses strong magnetic fields to create a 3-D image of the inside of the human body. This scanner could never have been invented without the experiments of Pieter Zeeman.
Pieter Zeeman demonstrated that magnetic fields have an impact on the light emitted by atoms. Later on it turned out that this was also true of light emitted by the atomic nucleus alone. This is the principle underlying MRI scanners. The impact of magnetic fields on light, and on electromagnetic radiation in general, is a phenomenon that physicists now refer to as the Zeeman effect.
With his breakthrough, Zeeman laid the foundation for various scientific analytical methods, proved a theoretical idea of Hendrik Antoon Lorentz, and revealed a founding principle of present-day quantum mechanics.
Electron
In the second half of the 19th century, physicists discovered that electric fields can impact the properties of light, a subject on which Pieter Zeeman defended his dissertation under the supervision of Lorentz. Later on, Zeeman was the first to demonstrate that magnetic fields also impact the light emitted by atoms. This was an incredible breakthrough and it allowed Zeeman to provide practical evidence for a theoretical idea put forward by Lorenz: the existence of electrons. Together with Lorentz, in 1902 he was awarded the Nobel Prize in Physics for the discovery of the Zeeman effect.
Zeeman and Lorentz’s insight was important because of its impact on the academic world of physics. The magnetic field of the Sun has a highly disruptive effect on our global communication systems – which is why it is important to carefully map this magnetic field so as to identify any irregularities in good time. Today, if you want to know anything about the magnetic activity of the Sun, you will make use of the Zeeman effect.
Measuring devices
The Zeeman Effect also proved to be very useful in developing various measuring devices, of which MRI scanners are the best known. But it also proved essential for scientific calculation methods such as spectrographic applications, which make use of nuclear magnetic resonance or electron paramagnetic resonance.
Scientists also suspect that birds are able to navigate thanks to a specific protein in their retina that is fine-tuned to the Zeeman effect; these birds can literally see the earth’s magnetic field.
Honorary degrees
In 1900 Zeeman was appointed Professor in Amsterdam. During his Amsterdam years, Zeeman made important contributions to measuring the effects of Einstein’s theory of relativity and to the development of mass spectrometry, a method for determining which substances occur in a given material. This method is still used by chemists on a daily basis.
Zeeman was awarded ten honorary degrees, from such universities as Gottingen, Leuven, Oxford, and Paris (Sorbonne). Despite this great international fame, Zeeman remained the simple, courteous, somewhat distant man he had always been. He did not like to travel. He preferred instead to be in his laboratory or at home, where together with his wife he graciously welcomed many international scholars. Pieter Zeeman died in Amsterdam in 1943, aged 78.
