The Hawking Limit

The late, great physicist showed us how to keep embracing life and work even as his physical condition deteriorated

Early in life, I was especially sensitive to the conditions around me. Minor levels of background noise would spoil my concentration. But as I matured, I developed the skill of ignoring distractions and focusing only on substance. 

During a routine morning jog through the woods near my home last month, I fell down, bumping my forehead on a rock and fracturing my wrist. My consequent visit to Mass General hospital resulted in two stitches on my forehead and a cast over my arm. It could have been worse. There was even an added benefit to the fall as it shaved off a mole that I always wanted to remove from my face. I was fortunate to return home for dinner just before midnight. At 5 A.M. the following day, I went back to my routine jog with bandages covering my entire face and the cast around my left arm. Except for birds, rabbits and ducks, nobody was out so early after sunrise to notice my appearance. The circumstances did not feel strange. I ignored the materials wrapped around my body as if they were pieces of new clothing, and focused entirely on the run.

In online meetings throughout the day, my postdocs and students were stunned to find out that I had carried on with my jog instead of taking some rest. I reasoned that the fun in life is all about the struggle with challenges and the effort to accomplish tasks despite obstacles. 

Achieving goals against all odds makes life worth living and celebrates the resilience of the human spirit. The most inspiring example is Stephen Hawking, who despite being paralyzed by a motor neuron disease and unable to speak, became one of the leading physicists of his generation. For half a century, he was attached to a wheelchair.  After losing the ability to speak, he communicated through a speech generating device, initially activated by a hand switch and eventually—when he could not move his fingers—by a single cheek muscle, facial expressions and eyebrow movements. 

In 2006 Hawking stated that his greatest unfulfilled desire was to travel to space. The following year, he flew aboard a reduced-gravity aircraft (affectionately known as the “Vomit Comet”) off the Florida coast to experience weightlessness. A decade later, he traveled to New York City for the public announcement of Breakthrough Starshot, the first funded initiative for interstellar travel. This was followed by a visit to Harvard University for the inauguration of the Black Hole Initiative. Despite being 74 years old on this trip, Hawking hopped from one public event to another, including a Passover dinner at my home. His caretakers noted that after one of the evening events, he told them: “I am bored. Let’s go to the hotel bar and have some fun.” 

Hawking’s life demonstrates that human identity is separate from the physical circumstances wrapped around it, natural or custom-made. Many other examples lie in between my mild injury and the Hawking limit, defined as the extreme condition when most of the human body loses functionality. What establishes the human identity, then? It is certainly not a fully functioning body, although it definitely requires a functioning human brain. As René Descartes noted: “I think, therefore I am (Cogito, ergo sum).”  

Since thoughts establish a sense of identity, groups of people could share the same identity. In the futuristic era of genetic engineering, one could imagine artificially duplicating a genetic code to a large number of copies, as an extension of the natural birth of identical twins or higher multiples. This would increase the likelihood of survival for that genome under dangerous circumstances such as those realized in space travel. Future missions to Mars or more distant destinations could be crewed by duplicates of humans sharing the same genetic material, so that if some are lost, other copies might survive. The approach would echo the effect of Gutenberg’s printing press, which, in producing identical copies of the Bible, made each of them less unique or precious.

Hawking’s funeral service on March 31, 2018, took place at the Church of Great St. Mary in Cambridge University and ended with the choir of Gonville and Caius College singing Frank Sinatra’s song “Fly Me To The Moon,” which continues with the words “let me play among the stars.” After his remains were laid to rest at London’s Westminster Abbey, a six minute broadcast, drawn from a speech in his synthesized voice, was beamed towards the nearest known black hole A0620-00 from a radio antenna in Spain.

Hawking’s resilience could serve as an inspiration for our future in space. Advanced space missions might carry copies of entities at the Hawking limit, possessing a common collective identity separately from the physical equipment that serves them. Without bumping my body against a terrestrial rock and temporarily compromising some of its functionality, I would have never recognized this fascinating possibility.