It has been just over a year since Stephen Hawking died and you started asking more questions about my time working with him.
As you know, this is not something that I talk about much, but because you have asked specific questions, I will try to answer them.
I joined Stephen as his Graduate Assistant in October 1992, after responding to an advert in New Scientist. I was following my job mantra of 'that looks like it could be fun!' My role was varied and was never the same two days running.
Stephen had a strong team around him, anchored by the Cosmology Group's secretary, Sue, and I was just one part of that organisation.
Some of Stephen's mail ended up in my in-tray, asking questions about paths to study physics or mathematics, looking for specific answers to homework questions (someone else I know does that!), wanting explanations of concepts that they hoped Stephen could explain or offering proofs of theories that spread over many pages.
With help from Stephen's graduate students I answered as many of the questions as I could, encouraging students to continue to study science and suggesting further reading in the topics that they were interested in.
Although Stephen had a computer on his wheelchair, it was not networked in 1993. This meant that I had to prepare scientific papers for Stephen to read and to answer some of his emails. Stephen's wheelchair computer was designed by a company in Cambridge, and used American software to control everything through a clickable micro-switch - this was probably the single most unreliable part of the whole system, which I remember replacing several times!
I also had several administrative duties for the cosmology group, like managing the paperwork for a recruitment and looking after the group's computer lab.
The advert I replied to
A portrait of Stephen taken at Science World Vancouver in 1993. His nurses are at the sides and I'm at the back
Travel and public speaking
Stephen seemed always to be travelling, whether at home or overseas. Most of the overseas trips were to conferences or for study at other institutes.
When we travelled overseas, or in the UK to speaking events, I would drive Stephen and his nurses in an adapted minivan. This had to hold Stephen's wheelchair securely and have safe seating for all of the passengers. A friend used to joke about newspaper headlines if I were to crash...
Stephen's wheelchair and computer ran off two large car batteries. These also had to travel with us, even overseas. It was quite difficult to convince some airlines that we could safely load the computer and its power supply for Stephen to use during a transatlantic flight.
When we arrived at the destination it was my job to ensure that all of the technology worked.
I only had two failures and one 'issue'.
In Japan I forgot that the mains power is 100 volts, and our US transformer expected 110 volts. This meant that the batteries did not charge properly the first day, and I had to get a special transformer from the hotel.
At a talk in Oxford, at the University Union, I forgot to talk to the organisers about public address facilities. When we got there we found enough equipment to amplify Stephen's speech synthesizer, but had no connecting cables. I had to pull out a box of bits and solder a cable together on the stage.
The only other issue was when Stephen was promoting the video release of his film 'A brief History of Time'. Leonard Nimoy (who played Mr Spock in the original Star Trek series) introduced Stephen, who wheeled out onto stage. Unfortunately, the microphone plug was loose in the synthesizer output socket, so he had no voice. That one was fixed in the best technical style with blue-tac to hold everything tight!
Stephen gave two types of talks - technical papers to his colleagues and peers, and public lectures open to anyone who could get a seat.
The technical talks were way over my head. When Stephen wanted new diagrams for these talks he would describe them to me and I would ask the graduate students for help interpreting the instructions. I can still not draw a hyperbola or parabola without reference to a text book!
I remember that the technical talks were very much the presentation of ideas and then discussion amongst peers. Not everyone agrees about science, but consensus can be reached with civil discussion. I am not sure how many Nobel Prize winners I met on my travels, but they and all of Stephen's collaborators were decent human beings who respected each other. They never attacked or criticised the person, but often had different ideas about the science.
Stephen on stage at Science Wold Vancouver, 1993.
Public talks and appearances
Public lectures were another thing altogether. Stephen had been told that every equation he put in his book 'A Brief History of Time' would halve the readership, so I do not remember equations on any of the projected images that accompanied the talks.
Stephen could pack an auditorium within days of a lecture being announced, and in the USA I remember one talk with more than 3000 in the audience having a television relay to more people assembled outside. My role was ensuring that Stephen's speech synthesizer was audible - which included a sound check before the talk - and then following a script so that the right illustrations accompanied what he was saying.
Immediately after the talk Stephen would take a limited number of questions - remember that it took a while to write out the answers - and I would (with his permission) answer some of the most frequent non-science questions whilst he wrote. And this leads neatly in to your next question:
How did his speech converter sound, and when doing shows, how did he get miked?
Stephen had a fairly early speech synthesizer, and was offered 'upgrades' to a 'better' one whilst I worked with him. But he kept the voice of the synthesizer the same because he said it had become his. Even now, when I read anything that he wrote, or a quotation in a newspaper, I hear it read in his voice.
I have found two videos on YouTube, one of which is about the final computer he used, and the other about him. As I mentioned earlier, the computer that Stephen had in 1993 plugged directly into a PA system (or the massive car-phone that was added that year.) These videos show him using an ordinary microphone next to the computer's speakers.
What made him so famous?
Stephen wrote the book 'A Brief History of Time' which was published in 1988. This is probably the most memorable thing to most people.
University students would have learned about 'Hawking radiation' at the event horizon of black holes in physics lectures, but that's full of concepts that are hard to grasp.
When a film was made based on Stephen's life and the book, he was quoted in the Washington Post :
And while Hawking appears to enjoy the added boost the film is giving to the celebrity he found with his book, he underscores a conviction that his personal fame is a means to serve the larger purpose of bringing the cutting edge of science to the people. Why?
"Science and technology have made major changes in the way we live in the last 50 years," he says. "And they will make even greater changes in the next 50. In a democracy, it is vital that the public have a general understanding of science so that they can make the decisions that need to be made."
And then there was also Stephen's disability. A bit like Harry Potter, Stephen was the scientist who lived. His diagnosis of ALS meant that every extra day was a bonus, and that he was recognised for his wheelchair and disability by many people. The internet will tell you about the charitable work that he did, but his passion in life was science.
What did you learn about science and how it was communicated?
This is probably the hardest thing to write about. I think that I did not learn much about cosmology (that has stuck, that I could tell you about without research), but I experienced at first hand the sheer power of celebrity science communication.
Stephen was one of the first 'rock-star' scientists, and could fill halls for talks, or museum galleries for opening, by simply announcing his presence. He was invited to address the Congress of the United States to support the Superconducting Supercollider, but was unable to travel and sent a video instead.
Roger Highfield talks about much of what Stephen did to popularise science in this blog, where he touches on Stephen's influence on popular culture. Stephen appeared in Star Trek, The Simpsons, and the Big Bang Theory. His voice was sampled for a Pink Floyd album, which probably makes him the only rock star with a PhD (other than Brian May of Queen - also a physicist!)
To talk a little about communicating science with the public, Stephen sparked his own public into being by having a big idea and being able to explain it to people at their own level. It is said that not everyone who bought 'A Brief History of Time' has read it, but its success lies in changing people's attitudes to science and making them aware that science in its many forms influences all parts of life.
A final thought from me
Somewhere at home is a letter that I received from a Japanese school student, thanking me for responding to his first letter to Stephen, and telling me that he intended to continue his studies. He sent a tie as a gift, and whenever I see or wear it, I am reminded that science is for the greater good of all, and we all need to understand as much about it as possible.
Stephen in the captain's chair of the Star Ship Enterprise, on Star Trek The Next Generation