Stephen Hawking -
The Physicist Who Redefined Boundaries

Stephen Hawking was born on January 8, 1942, in Oxford. His father, Frank, was a physician specializing in tropical diseases, and his mother, Isobel, was among the first women admitted to study at Oxford. Stephen was followed by two younger sisters, and the family later adopted a son.

Hawking's father hoped he would pursue a career in medicine, but young Stephen was primarily captivated by the skies and stars. An active child, he enjoyed climbing, dancing, and sports. Despite his evident intelligence, he did not excel academically, instead channeling his energy into creative pursuits like making fireworks, building model airplanes, and inventing board games. With encouragement from his math teacher, Hawking and a group of friends constructed a basic computer using discarded components from old electronic devices.

By the end of high school, Hawking had significantly improved his academic performance and graduated at 17. Although he wanted to study mathematics at university, his father urged him to attend Oxford, which did not offer an undergraduate degree in mathematics. As a result, he chose to study physics and cosmology. In 1962, he graduated with honors and proceeded to pursue a doctorate at the University of Cambridge.

During his doctoral studies, Hawking began to notice a decline in his motor functions. He was soon diagnosed with ALS, a progressive motor neuron disease that progressively damages the nerve cells responsible for muscle movement. The disease eventually leads to complete muscle failure, leaving patients unable to eat or breathe without assistance. Most ALS patients have a life expectancy of just a few years after diagnosis. Initially, doctors gave Hawking a prognosis of about two years to live, leading him to consider abandoning his studies. However, it later became apparent that his condition progressed more slowly than expected. Encouraged by his doctors and his supervisor, Dennis Sciama, Hawking decided to continue his studies.

However, as his condition progressed more slowly than expected, he was encouraged by his doctors and his supervisor, Dennis Sciama, to persevere, and he decided to continue his academic work.

However, as it became clear that his condition was progressing more slowly than expected, he was encouraged by his doctors and his supervisor, Dennis Sciama, to continue his academic pursuits.

In his doctoral dissertation, Hawking focus on the concept of a singularity - a region predicted to exist at the center of black holes - and extended it to the entire universe. A black hole is an object with an immense mass concentrated into an extremely small volume, resulting in a gravitational pull so intense that nothing, not even light, can escape it. At the center of a black hole lies a singularity—a point where most of the mass is concentrated, with density approaching infinity according to the solutions of the field equations. At a time when the Big Bang model was still scientifically controversial, Hawking calculated the properties of the expanding universe and demonstrated that the universe itself could have originated from such a singularity.

About a year before his death, Hawking published his work, entitled Properties of Expanding Universes, on Cambridge University’s open-access platform. The publication garnered so much attention that the university's servers crashed under the volume of incoming traffic.

Entropy cannot disappear, even in a black hole, which emits radiation. Jacob Bekenstein (right) and Stephen Hawking | Photos: Wikipedia, Public Domain

Radiation from a Black Hole

Hawking’s work heavily relied on breakthroughs by the renowned mathematician Roger Penrose, who was later awarded the 2020 Nobel Prize in Physics and the 1988 Wolf Prize in Physics. The two continued collaborating on the theory of the universe's evolution, and, in 1970, jointly published a comprehensive paper demonstrating that the universe's expansion from a singularity is consistent with the theory of general relativity.

Hawking continued his research at the University of Cambridge, soon returning to the study of black holes. Collaborating with several other researchers, he formulated four laws of black hole mechanics, which describe the principles governing their formation and behavior..

His major scientific breakthrough came in 1974 when he demonstrated that black holes are not entirely black—something can escape them in the form of radiation. Hawking’s insight was based on the uncertainty principle, which states that the energy of a system cannot be determined with absolute precision. He reasoned that even in a perfect vacuum, energy can never be exactly zero, leading to quantum fluctuations. These fluctuations manifest in pairs of particles and antiparticles spontaneously forming from the vacuum and then annihilating each other. If such a pair forms precisely at the boundary of a black hole—the "event horizon," beyond which everything is absorbed by the black hole—one particle may be absorbed by the black hole while the other escapes. This escaping particle constitutes the radiation emitted by black holes, now known as Hawking radiation.

Hawking’s calculations were based on the work of Israeli scientist Jacob Bekenstein, who had shown two years earlier that black holes have entropy, meaning a measure of energy disorder. The second law of thermodynamics states that entropy always increases, and Bekenstein realized that even when matter is absorbed by a black hole, its entropy does not disappear. He developed a method to calculate the entropy of black holes. For this reason, the radiation predicted by Hawking is sometimes referred to as Hawking-Bekenstein radiation.

Hawking predicted the existence of particles that could be emitted from the event horizon of a black hole, calculated the temperature of this radiation, and demonstrated that it corresponded to the entropy proposed by Bekenstein. Hawking radiation has not been directly observed in black holes in space because its intensity is far too weak to detect. Last year Israeli researcher Jeff Steinhauer from the Technion demonstrated the existence of such radiation in an acoustic black hole—an apparatus resembling a black hole that absorbs sound waves rather than electromagnetic radiation.

Hawking’s groundbreaking contributions earned him numerous prestigious scientific awards, including the Eddington Medal (shared with Penrose) from the Royal Astronomical Society, the Maxwell Medal from the British Institute of Physics, and the Einstein Medal. In 2009, he was honored with the Presidential Medal of Freedom  by U.S. President Barack Obama.

A Brief History of Time

Since the 1980s, Hawking continued to explore fundamental questions in physics, such as the nature of time and the issue of information loss in black holes. Hawking argued that such information would be lost forever once the black hole ceases to exist. In reference to Einstein's famous remark, “God does not play dice,” which opposed the probabilistic aspects of quantum mechanics, Hawking remarked, "Not only does God play dice, but... he sometimes throws them where they can't be seen.” Many physicists opposed Hawking's stance, asserting that it contradicted the principle of information conservation central to quantum mechanics. In 2004, Hawking revised his position and conceded that he had been mistaken.

Hawking gained much of his fame outside the cosmology community through several popular science books he authored. The first and most famous book was A Brief History of Time, published in 1988. The book became a bestseller, was translated into numerous languages, and sold millions of copies worldwide. Following its success, Hawking published additional books, including Black Holes and Baby Universes and Other Essays, The Universe in a Nutshell, and The Theory of Everything.

In 2014, Hawking’s autobiography, My Brief History, was published. Several biographies about him have also been released. His life story is the focus of the film The Theory of Everything (2014).

Despite his medical condition, Hawking married Jane Wilde, whom he had met shortly before the onset of his illness. The couple had three children: Robert (born in 1967), Lucy (1970), and Timothy (1979). They divorced in 1995 and Hawking married Elaine Mason, the nurse who had cared for him with dedication for many years.

After losing his ability to speak due to his illness, Hawking began using a computer-based communication system. This system allowed him to select letters, words, or phrases from software that converted his choices into synthesized speech. Initially, he operated the system with his hand, but as his condition progressed, he switched to a device that allowed him to control the system using a single facial muscle. Although the system improved over time, Hawking chose to retain the original synthetic voice, saying its metallic tone had become a signature part of his identity.

Without Limits

Despite his physical limitations, Hawking never stopped exploring the world, traveling to all seven continents, including Antarctica. He even dreamed of traveling to space and was set to be one of the first passengers on British entrepreneur Richard Branson’s ambitious space tourism initiative. In 2007, Hawking had the opportunity to experience zero gravity aboard an astronaut training plane that performed extended dives, providing passengers with the sensation of weightlessness during free fall. "The zero-G part was wonderful and the higher-G part was no problem. I could have gone on and on. Space, here I come!" he said after the two-hour experience.

When asked on another occasion why he enjoyed taking risks, Hawking replied, "I also want to show that people need not be limited by physical handicaps as long as they are not disabled in spirit"

Hawking’s status as a groundbreaking scientist and author of popular science books, combined with his medical condition, made him a globally recognized figure. He even appeared as himself in popular movies and TV shows, including The Big Bang Theory and The Simpsons. In one notable scene from Star Trek: The Next Generation, Hawking is shown playing poker with other legendary scientists, Albert Einstein and Isaac Newton

Hawking gave numerous interviews on scientific and existential topics, providing the media with many fascinating statements. He frequently expressed his belief in the likelihood of extraterrestrial life but warned that contact with it could be dangerous for humanity. ""Considering the number of planets and stars that we know exist, it's extremely unlikely that we are the only form of evolved life," he said. "If aliens ever visit us, I think the outcome would be much as when Christopher Columbus first landed in America, which didn't turn out very well for the Native Americans.”

He also frequently expressed his views on religion: "Before we understand science, it is natural to believe that God created the universe. But now science offers a more convincing explanation," he said.

In what was likely his final interview, conducted just days before his death, Hawking appeared on the StarTalk show and was asked what existed before the Big Bang. He explained that there was nothing, as time itself began with the Big Bang.

Hawking used his public platform to advocate for research into ALS and even donated money to support such studies. He also worked to promote the rights and status of people with other disabilities. Additionally, he frequently spoke out on public and political issues. In1968, while still using walking sticks, he participated in a protest march against the Vietnam War. Later. Later, he sharply criticized the Allied invasion of Iraq in 2003, calling it a "war crime,"  and even announced his support for an academic boycott of Israel. He also called for global nuclear disarmament and urged worldwide action to combat climate change.

Hawking often took pride in the fact that he was born exactly on the 300th anniversary of Galileo Galilei's death. Symbolically, he passed away on the birthday of another great physicist, Albert Einstein. Physicist and popular science author Michio Kaku said about Hawking "Here was a man, not since Einstein, who can communicate to the public about the meaning in the universe itself. Cosmic questions that we all think about at night.”

"The image of Stephen Hawking, in his motorised wheelchair, with head contorted slightly to one side and hands crossed over to work the controls, caught the public imagination, as a true symbol of the triumph of mind over matter," wrote Roger Penrose in his eulogy for his friend and scientific collaborator. "As with the Delphic oracle of ancient Greece, physical impairment seemed compensated by almost supernatural gifts, which allowed his mind to roam the universe freely, upon occasion enigmatically revealing some of its secrets hidden from ordinary mortal view."