Stephen Hawking was born on January 8, 1942, exactly 300 years after the death of Galileo, and died March 14, 2018 on the anniversary of Einstein’s birth. The astrophysicist is bookended by great scientific thinkers in a cosmic joke about non-linear time.
Professor Stephen Hawking was the most famous scientist of our time. Hawking warned about the threats of nuclear war, genetically modified viruses, artificial intelligence, and aliens. He published notable work on black holes and space-time, as well as communicated his knowledge of the universe to the general public. Hawking received thirteen honorary degrees as well as several metals and prizes including the Fundamental Physics prize (2013), Presidential Medal of Freedom (2009), Copley Medal (2006) and the Wolf Foundation prize (1988). He was a Fellow of the Royal Society and a member of the US National Academy of Sciences. However, his notoriety has in some ways eclipsed his contributions to science and human understanding.
Stephen Hawking gave to humanity the same as we all do: ideas. Hawking was one of the world’s foremost theoretical physicists and his ideas changed our understanding of the basic laws which govern the universe. Along with colleague Roger Penrose, Hawking demonstrated that Einstein’s general theory of relativity implies that space and time have a beginning in the Big Bang theory and an end in black holes (1970).
This understanding of fundamental physics indicated that it was necessary to integrate the theory of general relativity with quantum theory. The general theory of relativity is that physical phenomena (light, gravity, and time) are relative to the observer and observed objects. Quantum theory explains the nature and behavior of matter and energy on the atomic and subatomic level. In unifying these theories, Professor Hawking demonstrated that black holes are theoretically not completely black; instead black holes should emit a type of radiation known as ‘Hawking radiation’ before they eventually evaporate and disappear (1974). The radiation cannot emit from a black hole because it has an event horizon: a region of space where the gravitational field is so strong that nothing can escape from it, not even light. The radiation is instead caused by cosmic refugees, virtual particles that escape destruction near a black hole.
From here, Hawking argued that the ‘cosmic refugees’ were void of information due to proximity to a black hole. This assertion sparked a controversy that became known as the information paradox. The information paradox is speckled throughout his career especially in Information Loss in Black Holes (2005), Information Preservation and Weather Forecasting for Black Holes (2014), and The Information Paradox for Black Holes (2015).
Hawking contributed to our fundamental understanding of space, time, and matter that physicists will continue to question and build upon for the duration of human existence. Although it remains a paradox, most physicists (including Hawking) now believe that black holes do not destroy information. Some believe that black holes save information that is released in the radiation after the evaporation of a black hole; however, the physics just isn’t in yet.
This small glimpse into Hawking’s contributions to science is just one of numerous theories and breakthroughs that will have physicists working for decades to come. If you want to understand more about the universe through Hawking’s work, I recommend A Brief History of Time and The Theory of Everything. These are just two of Hawking’s contributions to science education, and his more than 150 publications are available from his PhD thesis Properties of Expanding Universes (1965) to A Smooth Exit from Eternal Inflation (2017).