Magnetic resonance imaging (MRI) is an essential technical tool for looking into matter and also into the human body and, for example, for understanding the human body. However, the spatial resolution of conventional MRI devices is limited to the millimetre scale and therefore cannot be used to study very small structures such as biological molecules and other nano-objects. Efforts are therefore underway to develop new types of methods and instruments that will allow to broaden the scope of MRI to the order of a nanometre (= one millionth of a millimetre) or even to individual atoms. Such an instrument will allow us to directly image the structure of biological molecules and thus better understand how they work.

In this lecture we will look at how nano-MRI technologies work and what makes them so difficult to develop. How can a magnetic force be measured that is only 0.000000000001 times the weight of a fly? What does an atomic nucleus have in common with a spinning top? And why does quantum mechanics play a role in these precision measurements? We will approach all these topics without getting bogged down in mathematical details.