Title: Professor of Physics and Electrical Engineering Emeritus
University: Harvard University
Years with University: 43 years
- Paul first arrived at Harvard in 1961 as an undergraduate student. He is still there, now as a professor of both physics and electrical engineering, after a 43-year career.
- Along with Winfield Hill, Paul wrote, “The Art of Electronics,” one of the world’s most renowned works on circuit design.
- Paul is a leader in the search for extraterrestrial intelligence (SETI).
When you think back to the path you took to get where you are, is there a time you can point to and say, “That’s when I wanted to be an engineer?”
I’ve always loved engineering and building things. I have an older brother who became an electrical engineer and I thought to myself, “I’m going to be an electrical engineer just like him.” He went to MIT, so I always planned on going there as well and majoring in electrical engineering. But he said to me, “Major in physics. It’s more flexible because you can always do engineering after, but not the other way around.” My mother was adamant that I go to Harvard. So I listened to both of them and ended up majoring in physics at Harvard.
While I was there I did all kinds of cool stuff like participating in the first terrestrial experiment of one of the predictions of Einstein’s theory of relativity. That made me realize you can do other things with electronics besides just building gadgets. In fact, electronics serve as a complement to science. It was through that route that I got into scientific instrumentation in a serious way. I eventually became passionate enough to write a book and teach a course about this stuff!
What intrigues you most about physics, electronics and engineering?
I love experiments that are small enough that one person can build it, run the experiment and get the results in less than a lifetime. A lot of the experiments that I’ve done are like that. It’s fun because you can engage a graduate student in an experiment that will finish in the time that they get their degree as opposed to 20- or 30-year efforts. It’s almost like table-top science with table-top electronics.
What specifically drew you to teaching?
There are incredibly bright and enthusiastic kids that can do amazing things with just a small push in the right direction, which is what drew me to teaching. In particular, I love teaching electronics more than physics because of the way electronics works and the way you can think about it. It’s much more focused on solving a problem. Engineering courses tend to present a circuit and say, “Analyze the hell out of this using all the equations.” Whereas the approach for the course I teach at Harvard, Physics 123: Laboratory Electronics, is based on the experiences I’ve had in experimental physics. This encourages students to figure out how to build something to measure and control a circuit. You reach into your tool box of electronic techniques and attempt to knit together front-end transducers, amplifiers and digitizers to make something really cool.
That’s the approach that I love teaching to my students and I think they also enjoy it because they can immediately begin designing circuits that do something, as opposed to taking an analytic approach. There is a greater appreciation for hands-on experience nowadays due to the whole maker movement. Back in the 1960s and ‘70s there weren’t any Arduinos. I love that people are excited about designing and inventing. There is once again a belief that anyone can build things.
What’s the most challenging part of your job?
By the end of most lectures I think I’ve done a good job because I see students nodding their heads or vigorously taking notes. Then they go into the lab and wire up these different circuits. But when I ask them about it a week later they give me a blank stare. So I think a big challenge I face as a professor is making sure I’ve actually engaged their brain and gotten them to understand what I call circuit intuition as opposed to thinking of it as some sort of route exercise. That’s the toughest part because by the time you’re good at it it’s time to retire!
The other challenge is teaching a group of students with different skillsets. Some are way smarter than the teacher and will figure things out really quickly. But then there are other students that struggle. It’s not like a mechanics or electromagnetism course they’ve taken where they write down the equations and learn how to do that. I have to deal with both kinds of students at the same time in the same classroom. I don’t want to bore the students that are going fast, but I also don’t want to run away from the ones that are having a hard time. Another issue is making sure those that are really good aren’t always the ones answering my questions. That has been and always will be a challenge.
Is there a particularly exciting project you’ve had the opportunity to work on in your career?
It’s difficult to choose between my book, “The Art of Electronics,” and my work with the search for extraterrestrial intelligence (SETI). When it came out back in 1980, the book offered a different approach to electronic design compared to every other piece of literature that was out there. I think the reason for that is my background was in physics, where I learned electronic design on the job as opposed to taking electrical engineering courses and learning it the way most engineers do.
It was clear to me and my co-author Winfield Hill that the people actually designing circuits in the real world thought about them the way we did, which meant going light on the equations. Those equations don’t show how to design circuits, but instead focus on optimizing a piece of a circuit. There was a disconnect between the way professors taught electronics and the way real designers designed them.
What sparked your interest in SETI?
I got into it as a graduate student when Frank Drake, the pioneer of modern SETI, gave talks at Harvard about it. There was also a guy here at Harvard, who is probably my biggest hero, Ed Purcell, the discoverer of nuclear magnetic resonance, who gave a wonderful talk around 1960 about radio astronomy and communicating through space. When I had a sabbatical coming up I wrote to Drake and asked to visit him in Puerto Rico in order to work on the Arecibo, the world’s largest radio telescope. Ever since, I’ve been hooked.
The most exciting thing about it is the potential payback. A colleague of mine once said, “Horowitz, you have a one in a million chance of becoming the most famous person ever.” There are maybe only a dozen people in the whole world searching for life beyond earth right now. You want to talk about a niche field, this is it.
Given your extensive work with SETI, do you believe there is life on other planets?
The galaxy is littered with planets. We know from the last few years that there are more planets than there are stars. What happened on earth probably happened on other planets as well. It’s entirely plausible, in fact I would say it’s a certainty, that there is life on other planets in the galaxy, if not in our own solar system. If the processes that led to intelligence and ultimately technology happened elsewhere then there are civilizations with which we can communicate.
Contrary to what people may think, the most advanced technology we have on earth now must be considered pretty primitive because it has only been around for 50 years, maybe 100 if you want to stretch it. One hundred years out of the total three and a half billion that life has been on earth is just the last little sliver and yet we can already communicate with a sister planet no more advanced than we are using radio technology. We already have the technology to contact them, now all we need to do is find them.
What’s the best piece of advice you’ve ever been given?
Back in the 1960s, I knew an engineer who worked on the NR-1, which was a nuclear submarine. Eventually he got out of engineering and went to Wall Street to become incredibly wealthy, but years ago he wrote to me and said, “The years I spent as an engineer were the most enjoyable of my career. I always tell young people to find something they love doing every day and do it. No matter how much money you make, you never think it’s enough. So chasing money is a big mistake. If you have any students who don’t get that, send them to me.”
I once received similar advice myself after having some thoughts about leaving the SETI business and going into something a little more conventional. A colleague of mine said to me, “Do the thing you love, the thing that gets your heart pumping.” I think I made the right career decision because even after having done this for 20 years, I still look forward to Monday mornings. Anyone who can say that is doing the right thing.
Paul with noted astronomer Carl Sagan and filmmaker Steven Spielberg at the opening of the "million-channel extraterrestrial assay" (META)