# Jacob Bekenstein

Wolf Prize Laureate in Physics 2012

**Jacob Bekenstein**

#### Affiliation at the time of the award:

**The Hebrew University of Jerusalem, Israel**

#### Award citation:

**“for his work on astronomical super-massive objects called ‘black holes’ that showed they can possess a statistical-thermodynamic property called entropy even though the internal dynamics could not be known. This work created an entire field of black hole dynamics which has become a cornerstone in the important theoretical physics areas of quantum gravity and strings”.**

#### Prize share:

**None**

The most important discovery of Prof. Bekenstein (born 1947, Mexico) is his realization that black holes have a temperature and carry entropy proportional to the area of their event horizon. This has sparked the creation of an entire field devoted to the study of black hole thermodynamics where the theories of quantum mechanics, general relativity and statistical mechanics are deeply intertwined. This has led to advances in quantum gravity and string theory. He also demonstrated that it is not possible for an observer to measure anything about the black hole except their total mass, angular momentum and electromagnetic charge. This discovery led to the current description of black holes as very simple objects and provides constraints on theories that modify general relativity. These seminal advances have been used by many others and continue to have vast influence in cosmology and theoretical physics.

Professor Bekenstein discovered that a black hole possesses entropy, whose value is proportional to its surface area. Therefore it also has a characteristic temperature. This has led to a new understanding of black holes, but also to an interesting new question, namely, how do these new properties originate? Many research groups are now studying this question, the answer to which will necessitate an understanding of the microscopic structure and dynamics of the black hole.