What if the entire Universe - in all its complexity and variety - could be described in a single mathematical equation? It may sound impossible but we are actually almost there.

Until 1971, it was not understood under what forces most of the elementary particles interact. Together with his PhD supervisor at the time, Professor Martinus Veltman, Gerard 't Hooft developed the mathematics that allowed the unification of electromagnetism and the weak nuclear force, showing that the two were actually manifestations of the same force. Subsequently it was discovered how other forces could be handled in similar ways. This led to what is now known as the Standard Model. It explains all known subatomic particles and three of the four fundamental interactions: the strong nuclear force, electromagnetism and the weak nuclear force. Only the last fundamental force, gravity, remains unaccounted for.

Although a theory of unified electromagnetism had been previously proposed in the 1960s, attempts to make precise calculations were thwarted by meaningless results such as infinite probabilities. In 1971, Gerard 't Hooft published two landmark papers showing how the infinite probabilities could be tackled, a feat which allowed scientists to finally calculate the physical properties of subatomic particles with great precision. The model implied that the weak nuclear force isn't always weak and can affect the masses and other properties of particles infinitely strongly, so that a new formalism called "renormalization", is needed to talk about them.

The 't Hooft-Veltman calculational methods were used, for example, to predict the mass of a subatomic particle called the top quark, which was only experimentally observed much later in 1995. For their work, Profs 't Hooft and Veltman were awarded the Nobel Prize in Physics in 1999.

Gerard 't Hooft grew up in The Hague, born into a family of scholars. His grandfather and uncle were scientists, and his granduncle was the Nobel laureate Frits Zernike who invented the phase-contrast microscope. At the age of eight, Gerard told his teacher that when he grew up, he wanted to be "a man who knows everything", having forgotten the word for "professor" or "scientist."

He studied physics and mathematics at the University of Utrecht. Upon completing his PhD, he worked at CERN in Geneva for two years before returning to Utrecht to join the faculty. In 2076, he was appointed Professor at Utrecht University.

Prof 't Hooft is also the recipient of the 1981 Wolf Prize, the 1986 Lorentz Medal and the 1995 Franklin Medal, among others. He was one of the first to be awarded the Spinoza Prize, the highest scientific award in the Netherlands, and has been knighted commander in the Order of the Netherlands Lion and officer in the French Legion of Honour.

Today, Prof 't Hooft researches the enigmatic gravitational force and sub-microscopic black holes. He remains fascinated by the field because "nature is quite complex when the tiniest particles are addressed." Prof 't Hooft is also an ambassador for the Mars One project, an attempt to land the first humans on Mars and establish a permanent colony there by 2027. The asteroid 9491 Thooft was named after him.

# Speakers

Gerard 't Hooft

Nobel Prize in Physics

1999