---

Madame Chancellor, Mister President, honored guests and colleagues, graduands, and your parents, relatives, and friends: I’m very honored to be here, with all of the rest of you who are getting your degrees today.

We’re all here because of science. And I’m constantly struck by how science always moves forward – one of the few human institutions that can say that. So in the next very few minutes I’d like to talk about how.

Let me start with a very recent example from my own field. Three weeks ago, I was at the annual meeting of the Canadian Astronomical Society, held this year in Victoria. Hundreds of astrophysicists gathered to talk over new results, form collaborations, and exchange ideas. And in one of the featured talks, we heard about the details of a discovery that happened just a few months ago. In a rather normal galaxy 130 million lightyears away, a pair of neutron stars – the dead remnants of formerly active stars – spiraled in towards each other and collided. How do we know this? Because of the new technique of gravitational wave astronomy. The collision radiated a pattern of gravitational waves outward in all directions, a tiny part of which was detected and measured here on Earth, and these ripples in space had a particular shape and structure that could only be produced by a pair of colliding neutron stars.

Does all of this have any practical implications? Well, it’s like this. When two neutron stars collide, they touch off a firestorm of nuclear reactions, which rapidly build up lots of nuclei of heavy atoms – elements like cadmium, mercury, tungsten, platinum – and gold. Moreover, it seems now that this type of event may be the answer to a long-standing problem of where the heaviest elements came from. So, if you happen to be wearing a gold ring for example, or perhaps a bit of gold jewelry – you are wearing a little bit of cosmic wreckage. In fact, I’d say it’s worth getting a bit of gold jewelry just so that you can talk about where that gold came from.

As another example, consider what we’re all made of. The most common type of atom in our bodies is simple hydrogen. Those hydrogen atoms were formed almost 14 billion years ago in the early stages of the Big Bang and have been around since. The second most common atom inside us is oxygen – and those oxygen atoms were built up by nuclear fusion deep within the cores of massive stars long before our Solar System existed. The same is true for carbon and nitrogen and most of the other atoms inside us. We really are made of stardust – or if you prefer, we’re made of nuclear waste.

Another prominent recent example, of course, is the detection of thousands of planets around other nearby stars, and serious progress is now being made toward the goal of finding clones of the Earth, where we might in turn find evidence for life. All of this might happen sooner than anyone expects.

We live in an age of miracles and wonder. And I’m sure all of you can think of things from your own fields of study, of amazing frontier phenomena. New ideas, new tools and techniques.
But it’s not just ideas and tools; just as importantly, it’s the way science actually gets done. It’s often said that science is neither good nor bad – it’s just the use to which we put it that can be one or the other. I’m not sure that’s entirely true, but let’s shift the focus instead to the process of doing science. That’s, I think, an example of humanity at something approaching its best:

– What we do with information is crucial. We work best when there’s a free flow of information and a lot of sharing of ideas. Secrecy is discouraged, disinformation is not allowed, and national borders don’t mean anything.
– Science is very good at taking the long view. It can take all the brainpower and all the hard work that we can throw at it, and more besides, but persistence pays off. Individual work is important, and collaborative work is important. Narrow perspectives, shortsightedness, impatience don’t get you very far.
– Science is wide open for debate, any time. Any idea, interpretation, concept, or model, is open for challenge, as long as those challenges are based on evidence – not just opinion, or authority. The only authority in the game is Nature itself. Arguments about the evidence happen all the time and can get very strong, but they must not become personal; that’s out of bounds.
– Science is open-ended, just like nature is. Research questions always turn out to be richer and more diverse than we first expected. Those of you who are getting graduate degrees – Master’s or PhD’s – may appreciate that especially. You may have found that your thesis project had a lot of loose ends and questions that still needed following up and that your conclusions were just not as neatly tied up as you might have liked. Nature is not required to make sense, but unfortunately a thesis is.
– In science, we can live with uncertainty. If there’s not enough evidence to come up with a convincing explanation, then don’t make one up. Instead, get more evidence and see where that leads.

Is this a perfect system? Of course not; it’s human, and we’re all just human. But the ideal as a way of finding out how Nature works is a good one – an ideal that’s been painstakingly worked out over the past 400 years. Doing science is fun and exciting and demanding, because Nature is complex and challenging and rich and strange and fascinating, and we are a long way from running out of questions.

So with that, my time is up. I wish you all the very best of luck along that path. Do good science, support good science, and ask good questions wherever you find yourselves. And by doing that, you will be helping to save civilization.

Thank you very much for your attention.