Interview, January 2022

On 27 January 2022 Arthur McDonald was joined by 12 students from all over the world and from different disciplines within science for a conversation on the topic of being a scientist. Among the questions to McDonald were how he ended up in science, why he choose neutrinos, what keeps him going and lessons learnt. The conversation was moderated by Carin Klaesson, curator at the Nobel Prize Museum in Stockholm, Sweden.

Read the interview

Interview transcript

[Adam Smith] Oh hello, my name’s Adam Smith, I’m calling from Nobelprize.org, the official website of the Nobel Prize in Stockholm. Congratulations on the award of the Nobel Prize.

[AM] Thank you very much.

[AS] May I first ask, how did you hear the news?

[AM] Well, I received the phone call shortly after 5 O’clock my time, this morning, and was awoken to the wonderful news, and it was very surprising but very gratifying as well.

[AS] How extraordinary. What was your first reaction, what was the first think you did upon hearing the news?

[AM] I gave my wife a hug. [Laughs] She was awakened by the same phone call.

[AS] [Laughs] What is it about neutrinos which has kept you all so engaged all these years, what is it that makes them so very fascinating?

[AM] Well they are, along with electrons and quarks, fundamental particles that we do not know how to subdivide further, and therefore they make up a very fundamental part of the laws of physics at the most microscopic level, and therefore their properties are extremely important in terms of being able to understand our world in great detail. But they’re very difficult to detect and therefore their properties, for many years, were difficult to know, even the question of whether they have a mass that is greater than zero. We were presented with an opportunity to make a measurement which, if we were able to accomplish it, if we were able to reduce the radioactivity levels to a lowest level possible and build a detector the size of a ten story building two kilometres underground in a mine, that it was possible to make the measurement. And lo and behold, in 2002 we had an extremely clear result that showed that neutrinos do change from one type to the other.

[AS] What a lovely result, and it also must be enormous fun to play with such kit that you’ve described.

[AM] It’s fun, once you get there.

[AS] Yes.

[AM] Once you have the detector in operation and you’re sitting there observing a burst of light represented on your display screen you have the ability to observe particles that come directly from the core of the sun. They’re telling you what’s happing there right now in terms of the nuclear reactions that are powering it, you are able to make measurements of the fundamental properties of the neutrinos themselves and it’s a great experience to look at this data and realise that you are seeing things that are extremely fundamental in their nature.

[AS] That’s an extremely vivid and exciting image, yes, that neutrinos allow you to look into the core of the sun, which of course you can’t do with photons.

[AM] No that’s right, and it’s ironic that in order to observe the sun you have to go two kilometres underground. It’s not what you would expect, that that’s the best place to look into the core of the sun, but lo and behold it is. And the ability to understand how the sun burns is one other aspect of the measurements that is very interesting science as well and that we were able to contribute to in a basic way.

[AS] Wonderful, well, happily we’ll have the chance to speak about this more when you come to Stockholm in December to receive your Nobel Prize.

[AM] Thank you.

[AS] It’s been a real pleasure to speak to you, thank you, I hope you have a most marvellous day.

[AM] Thank you so much.

[AS] OK, bye bye.

[AM] Goodbye.

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