On Wednesday 14th March, the scientific community lost one of the key figures in popularising science. Stephen Hawking, cosmologist and professor at University of Cambridge, actively made science accessible to non-scientists by writing books such as “A Brief History of Time” and “The Universe in a Nutshell“. These books not only inspired many young people to pursue a career in STEM, but also brought the attention of mainstream society to fields such as Astrophysics and Cosmology. Obviously, this was not done single-handedly, but with the help of other scientists such as Carl Sagan. Not only this, but Stephen Hawking’s research led to breakthroughs and theories important in Cosmology.
Stephen Hawking’s contribution to the Big Bang
Working with scientist Roger Penrose, Hawking showed that General Relativity implied that the Universe began at a singularity, such as the one theorised by the theory of the Big Bang. He found that this also implied that the Universe ended in a black hole. His research in this field led to the next discovery.
In 1970, Stephen Hawking showed that black holes can emit black-body radiation, known as Hawking radiation. This is only theoretically proven, but it led to one of the most interesting paradoxes in Cosmology. The thing about Hawking radiation is that it is not like any other black-body radiation, it is special in the fact that it carries no information about the black hole. This is known as the no-hair theorem, meaning that all information about a black hole is inaccessible, as it has disappeared beyond the black hole’s event horizon.
The question arises: where does the information that enters the black hole go? The Black Hole Information Paradox is a paradox that comes from a conflict between General Relativity and Quantum theory. The paradox is the following: when information (i.e. light, radiation, objects, anything) passes the event horizon of a black hole, it is lost forever, as it cannot be retrieved from the black hole ever again, according to General Relativity. However, Quantum theory states that no information can be created or destroyed.
Hawking believed that this paradox resulted from the fact that there is not yet a unification between the theory of General Relativity and Quantum theory, and there are some holes in theoretical physics that need to be filled before completely getting to understand black holes.
Once again, a great science communicator who helped make major breakthroughs was lost. However, we must not forget all the legacy he left behind, in the form of the many lives that were changed thanks to his engaging science vulgarizations, as well as his humour and lively nature.
Editor: Maria ‘Stefi’ Ticsa