Dr Karl Kruszelnicki: ‘I took my hands off the artery – blood squirted up and hit the ceiling'

The Guardian

20-07-2025

You're about to give a series of talks on the history and explosion of AI. Who is your favourite fictional robot?
I guess the robots in general from Isaac Asimov. He came up with the three laws of robotics, which are basically that a robot has to obey a human, it can't harm itself, and it can't harm another human. My favourite robot is one [from Asimov's The Bicentennial Man] that served a family for many, many years – in fact, generations – and eventually became human.
If you could change the size of any animal to keep as a pet, what would it be?
To put a downer on it, we're full of children and nieces and nephews and grandkids, so we don't want pets. But I do see the value of a pet. It's tricky. In Australia, cats kill a million birds a day. Dogs are nice, but when I was a doctor in a kids hospital, once I realised that dogs would rip the faces off 15,000 kids every year, I kind of fell out of love with big dogs. So I reckon dogs. Shrink them down. A border collie, they're the smartest dog.
What do you do when you can't get to sleep?
Get up, work for a bit, then go to sleep again when I feel tired. If I'm awake enough to do stuff, I'll do stuff. I love reading. My job is to read the scientific literature and turn it into stuff that people can understand.
I've been reading articles about how we've got this history of human diseases over the last 37,000 years, and how many diseases have actually invaded our DNA, or how some frogs will fake death to avoid sex, or how the French in the early 1800s had the great moustache wars, or the TV viewing habits of dogs. Or the word 'cool' – where did it come from, and what's the concept behind it? Or the amount of energy used from AI to make a single picture, as opposed to a human, or why you get traffic jams in the middle of nowhere, or how you use earwax as a diagnostic tool. Or, if you get a shark and turn it upside down, about half the species will just stop moving.
And that's just today's reading!
What is your most controversial scientific opinion?
The two big ones would have to be climate change and vaccination, and the controversy behind them is just pointless. You know how insurance companies are making it more expensive in certain areas to insure because of extreme events caused by climate change? OK, so when do you think the insurance companies started doing that? 1973! [It wasn't until 1980 that] fossil fuel companies, with a budget of up to a billion dollars a year, started denying climate change. And that's why I've got this so-called controversy.
What is the oldest thing you own, and why do you still have it?
I've got a bit of rock from a mining site that was dated to 1bn years old. I've also a meteor that my father saw land in our front garden when I was a kid, and the next morning, we went out to dig it up. I reckon that'd be a couple of billion years old. It's about the size of a golf ball. It's now on the display shelf halfway up the stairs.
Would you rather die at the bottom of the ocean or out in space?
Probably space. But it depends how it happens. One thing I learned as a medical doctor is that everybody has to die, but you should have a good death. We had one patient who had cancer of the everything, and she was really going to die. We made it our personal project that she'd have a good death. We ended up cranking her morphine from 5mg a day to 30,000 – that's a big jump, isn't it? Her legs were the diameter of your wrist by the time she died, but she didn't die in pain. So that convinced me, I want to have a good death.
Sign up for the fun stuff with our rundown of must-reads, pop culture and tips for the weekend, every Saturday morning
If you're in, say, a submarine, and then the pressure overcomes the structural integrity of the vessel's walls, then you're dead in about a tenth of a second, a hundredth of a second – whereas in space, it might take a while to die, maybe a few minutes. So whichever one was quicker. But the view's nicer in space.
What is the strangest job you've ever had?
I started working at the steelworks at Wollongong when I was about 19. I ran a little aluminium boat measuring the acidity or alkalinity of the water in this little creek inside the steelworks. Depending on whether it was green or orange, it varied between incredibly acid and incredibly alkaline. And either way, it would eat through the skin of the aluminium boat in about six months.
Sign up to Saved for Later
Catch up on the fun stuff with Guardian Australia's culture and lifestyle rundown of pop culture, trends and tips
after newsletter promotion
Back then, I was taught 'the solution to pollution is dilution' – chuck it in the ocean, nobody will ever notice. It was pretty bad back then, and hasn't got much better since.
What is the most chaotic thing that's ever happened to you at work?
I was in an operating theatre. I was assisting. I was really tired. I'd done an incredibly long number of shifts, dozens of hours in a row, and I was instructed to lean on an artery. I started to fall asleep standing up, and the surgeon said, 'Hey, wake up, Karl!' I stood up with a jerk and took my hands off the artery – blood squirted up and hit the ceiling.
If you had to add any colour to the rainbow, what would it be?
Around the world, the number of colours that people see in the rainbow varies between four and 16. The reason we have seven colours in our rainbow is because of Isaac Newton. Besides being one of the true geniuses, he also spent more time on Bible studies than he did on science. And all the way through the Bible the number seven comes up all the time. Based on him following the work of some Muslim scientists, he did an experiment with a prism – like the Dark Side of Moon album cover, which, by the way, is wrong from a physics point of view.
Anyway, he sees these colours. Six colours. But he loves the Bible, and the Bible has seven everywhere, so he sticks in stupid fucking indigo. What sort of colour is indigo? It's just blue! So I refuse to add another colour to the rainbow. I'll go the other way; I'll remove indigo and get back to six colours.
Lastly, please settle this debate for us once and for all, scientifically: should tomato sauce be kept in the fridge or the cupboard?
The problem that you want to avoid is bacterial or fungal infection of the tomato sauce. Now, the tomato sauce, I imagine, would be mostly water, and then it's got some varying mix of fat, protein and carbohydrate, which would be foods for bacteria and yeast. If you stick it in the fridge, you really lengthen the time before the bacterial or fungal overgrowth gets dangerous. But you end up in the terrible situation that you shake and shake and shake the bottle and first none will come, and then the lot will because it's been frozen to a solid lump.
So the argument for not putting in the fridge is that it'll pour more easily. In that case, you need to actually observe, and if you start to see the first hint of bacterial or fungal contamination, feed it to the compost and get another bottle.
It sounds like you're pro-cupboard, pro-observation.
Well, life's complicated. Nothing's simple. I'm sorry. I'm probably overcomplicating life.
Dr Karl will appear at three events at Tasmania's Beaker Street festival, 12-24 August