As a neuroscientist by day and armchair cosmologist by night, the death of Stephen Hawking affected me in different ways
Like many of many colleagues, I was amazed yet puzzled that 76-year-old Stephen Hawking lived so long with amyotrophic lateral sclerosis (ALS), a neuromuscular disease that kills most people within five years. Even the baseball great Lou Gehrig succumbed after about four years.
Clearly, there was something unusual about the course of Hawking’s disease. His ALS surfaced in his 20s—at least two decades sooner than typical ALS onset—but still followed the usual disease course for ALS, a downward cycle of muscle wasting and atrophy. When he was fully paralyzed and in his 30s, the disease, inexplicably, stopped progressing. That he was able to live so long in this deteriorated state is a supreme example of willpower. Clearly he did not let his physical condition define his life. The fact that he was treated more consistently than most ALS patients probably helped contribute to Hawking’s longevity, too. But definitely he was an outlier.
Why his disease progressed differently than other ALS patients is another question altogether. Our laboratory uses various mouse models to study ALS. The one we use most frequently—the SOD1-G93A model—exhibits histopathological and functional hallmarks observed clinically in familial ALS. The mouse model progresses almost like clockwork meaning that if you have a cohort of SOD1 mice, they will only survive about 150 days following the onset of symptoms. The model is, in contrast to Stephen’s disease, very consistent.
This as we know, is not the case with humans. Although on average patients die with 4-5 years from the diagnosis, there are some rare cases where patients live well beyond that. Hawking is an extraordinary example of this exception, but even among more typical cases there is diversity. Some ALS patients have more upper motor neuron dysfunction, others more lower motor neuron dysfunction and others have a combination of both. Outliers are obvious clues that force us to think differently about disease. In ALS, perhaps the message is that we need many different mouse models of ALS to help us find therapies that work more effectively against this heterogeneous disease. We still have not been able to determine why sporadic ALS cases, which are the dominant population, develop. From a disease modeling perspective it is a scientist’s nightmare, but luckily there are emerging animal models which have a range of phenotypes, and progression of the disability varies.¹ Such animal models may enable more pertinent experimental designs from the human disease point of view.
Hawking’s theories about the universe also interested and fascinated me, but for different reasons than his ALS. I’ve always been curious about space, space-time, and the universe. I am not physicist, I don’t use physics or mathematical equations to try and figure out my place in the universe. However, Stephen had a unique ability, besides top-notch mathematics and physics, to describe and illustrate the visible (and invisible) universe in an understandable way. He allowed me to approach complicated and often theoretical astrophysical and cosmological phenomena when I just wanted to understand my place in the universe a bit better. Hawking helped to feed this hobby of mine by making his theories around black holes (Hawking radiation), string theories and the expanding universe accessible without losing my mind. He was simply a rock star in my eyes.
How do we fit into the universe as an organic species living on a planet circling a medium-sized star that belongs to a massive collective of stars in our Milky Way galaxy that is just one small piece in a cluster of galaxies? These local clusters form larger super clusters of galaxies and ultimately the observable universe.
The human brain contains about 100 billion neurons but is probably more navigable than the size of our whole universe, which is so vast that the most distant places can’t even be observed because light hasn’t yet traveled to my eyes to see them. With ever accelerating speed the universe is expanding, yet we never will.
This massive amount of information is sometimes difficult to absorb. That Hawking was able to use his mind to get a handle on the universe using the only organ in his body that continued to function normally, says a lot about our species’ potential in understanding complex human diseases. and on a larger scale, our universe.
- Liu et al. C9orf72 BAC Mouse Model with Motor Deficits and Neurodegenerative Features of ALS/FTD. Neuron. 2016 May 4;90(3):521-34.