Scientist Risked His Life To Settle A Physics Debate, And Then He Put The Video Online

Risking his wellbeing to settle a dispute? Yep! And it all began with a question of physics. Namely, “Can you get a vehicle powered by wind to go directly downwind quicker than the wind is blowing?” The guy who tried to answer that query is Dr. Muller. And he posted a video all about how he tried to win the argument, and later the bet, on his YouTube channel, Veritasium.

To attempt to prove it was possible, Dr. Muller took a ride in Blackbird, a wind-powered car whose inventor insists it could outpace the wind with the breeze directly behind it. This claim had sparked quite the controversy, leading University of California Los Angeles professor Alexander Kusenko to put up some money to say the YouTuber couldn’t prove it.

In fact, Dr. Kusenko was eventually willing to wager $10,000 that the Blackbird, or a model similar to it, could not achieve the feat. And the bet was certainly serious — so much so that such luminaries as Neil deGrasse Tyson and Bill Nye were willing to act as witnesses. But who is the guy who insisted that a professor of physics was making a bad bet?

Presenter Dr. Muller was born in Australia, although he grew up in Canada. He returned to the place of his birth for his studies and ended up working towards a doctorate in physics education, which he eventually achieved. He wanted to turn his Ph.D. to use in the creative world, which proved quite difficult.

Undaunted, Dr. Muller moved into the world of tutoring, where he worked as a head of science. But he quit in 2010 and a year later began Veritasium, his YouTube channel. Its episodes focus on “addressing counterintuitive concepts in science, usually beginning by discussing ideas with members of the public.” To do that it offers a lively mix of interviews and experiments.

If you’re thinking the name “Veritasium” sounds a bit like a chemical element, that’s no accident. It’s a combo of the word veritas, Latin for truth, and –ium, the ending of loads of elements. The channel has proved really popular, with more than 10 million subscribers, and its scientifically rigorous approach has also scored it plenty of press coverage and plaudits.

The channel’s not the only place you can catch Dr. Muller, at least not if you’re an Australian. He’s a fixture on Aussie TV, where he reports on science for state broadcaster ABC’s show Catalyst and on Ten’s breakfast show. His work as a journalist has scored him a Eureka Prize.

Dr. Muller’s conveyance, the Blackbird, is the brainchild of Rick Cavallaro. He’s an I.T. developer who’s branched out into fantastical machines that people say cannot exist. Well, he’s here to prove the naysayers wrong, having secured some corporate backing for his design for a three-wheeler powered only by air. He says the car can both run upwind and outpace the airflow downwind, too.

Skeptics just wouldn’t credit that the inventor could do it, claiming it was like a perpetual motion machine. It just didn’t fit with physics, they said. When articles mentioned Cavallaro and his invention, the commenters were cruel. Even science journalists and online gurus didn’t hold back, labeling him a “bozo.”

Cavallaro was a bit taken aback with the coverage, he told the BBC in 2014. He said, “They have this problem that their intuition tells them that it’s not possible, because once there’s no wind over the vehicle [when it is traveling at wind speed] it can’t harness any energy from the wind.”

But Cavallaro noted that people literally wouldn’t believe their own eyes when they saw the evidence. He added, “The thing that was most surprising to me was how much even professional engineers and scientists will not only rely on their intuition, but accept their intuition over a straightforward rigorous analysis, and real-world proof.”

The inventor explained what the problem was, saying, “The reason I think that most people find it counterintuitive is that you get to a point going downwind, when you are going at exactly the same speed as the wind.” At that point, say you were in a boat, if moving in a straight line you couldn’t go faster. That’s because you’d have no wind to push you, because you’d then be stationary relative to its speed.

But Blackbird doesn’t have a sail. It uses a propeller to power it, and in turn the propeller isn’t powered by the wind but by a chain leading from its wheels. The faster the car goes, the faster the propeller spins. Cavallaro said, “We didn’t invent or discover any new physics; we just have a clever way of exploiting some basic physics.”

The design had been around for a while before Dr. Muller took his ride in it. Cavallaro actually built it back in 2010 when he decided to prove his point. Then he took a Blackbird-type car for a drive at the airport at New Jerusalem, CA. It flew along at nearly three times faster than the wind behind it.

Not everyone was convinced, but one man who was is Richard Jenkins. He designed Greenbird, which cracked the record for the quickest vehicle powered by wind. His design works in the more typical sailboat way, but when he saw Blackbird, he was convinced. He now says, “To all fellow skeptics, start baking that humble pie, or eat your hat. Your choice.”

For lots of scientists, though, the idea was just not credible. You can make a vessel powered by wind go faster than the wind — if you’re running at an angle to the direction the wind is blowing. But if it’s right behind you, you’re out of luck. Or so the experts, who include Dr. Kusenko, maintained.

The hubbub over Blackbird came to Dr. Muller’s attention, and he decided to test it out. He told Vice magazine in June 2021, “There was so much debate in forums and people just couldn’t seem to get a definitive answer. There definitely seemed to be reputable people on both sides of the debate, and so [viewers] asked me to look into it and see if I can make a definitive video on the topic, which was the goal here.”

So Dr. Muller made a video in May 2021 that he believed proved the vehicle’s debated capabilities, but Dr. Kusenko then contacted him. He’s a fan of Veritasium, and he usually likes the YouTuber’s stuff, but this time, he couldn’t agree with it. Dr. Kusenko even made a slideshow that he put up on his website to show why he didn’t agree with the conclusions at which Dr. Muller had arrived.

Dr. Kusenko is on good terms with Dr. Muller, but he didn’t hold back with his criticism. He told Vice, “The physics explanation was clearly wrong, and the experiment was not properly designed to answer the question they wanted to answer. So, I sent Derek a friendly email pointing out the problems with this video.”

So Dr. Kusenko agreed to a $10,000 bet. To win it, Dr. Muller would need to put on show “a model vehicle with the same principle of operation as the Blackbird.” That would be enough, Dr. Kusenko agreed, to “constitute sufficient evidence that Blackbird can sail faster than the wind downwind as described.” This would entail Dr. Muller creating a model to run on a treadmill.

Dr. Kusenko told Vice shortly after the wager was laid, “Any model is good, as long as the model is proven to be equivalent to the real thing. The burden of proof is on the model-builder. To be honest, I don’t see any model succeeding because, as I show in my slides, the laws of physics make sustained sailing downwind faster than the wind impossible.”

The professor believed that the only reason Blackbird might seem to outpace the wind was if the speed of the wind changed. A gust of wind might speed up the vehicle, which would then continue at a faster speed for a while even though the breeze had slackened off. This would give the illusion of going quicker than the wind.

Dr. Kusenko told the magazine, “The car really does travel faster than wind for a short time, after the wind speed drops. Of course, the car is decelerating, and it can only move faster than the wind for a limited time, until the car speed drops below the current wind speed. How long this time window is depends on the design of the car, as well as on the difference in wind speeds before and after.”

Cavallaro, meanwhile, insists that his design does not in fact break the laws of physics — which is lucky, because we need them! No, it actually uses a propeller system that has never been seen before. And Dr. Muller added that after all, Blackbird had broken that land speed record in 2010, and that feat had been officially accepted by the North American Land Sailing Association.

Dr. Muller described the record to Vice, saying, “They were going 2.8 times the wind speed, and in fact, accelerating over the period of measurement. I look at that data, and I just say, you cannot make an argument that it was due to wind shear, wind gradients, or a gust.”

And the YouTube sensation had a bit more to say, adding, “I feel that the data that is out there does not support [Dr. Kusenko’s] conclusions. That is not to say that what he’s saying is wrong — it’s just that it doesn’t explain the observations. If you really look into the observations and the data that exists, his analysis falls short.” Sounds to us like he was saying Dr. Kusenko is wrong!

It’s even worse than just proving one scientist wrong. Worse, if the Blackbird actually did what Cavallaro claims it does, physics might be broken. Dr. Kusenko argued that if the vehicle could keep up a speed faster than the wind, then this would violate the law of conservation of energy.

Dr. Kusenko went on to argue, “If this kind of design were possible, there would be a market for it. For one thing, sailboats crossing the ocean and running with the trade winds could use help in the form of some mechanical propeller adding to the thrust of the wind. Unfortunately, this is impossible, which is why there are no sailboats out there utilizing propellers in this fashion.”

So what would Dr. Kusenko be doing with his $10,000 should he win? Well, not throwing a party to celebrate the inviolability of his beloved physics. Instead, he would be giving the money to Kudu. This is a website which he helped create that offers learning solutions.

So how did the real-world test go? In the video of Dr. Muller’s attempts to prove that the Blackbird really can go faster than the wind, we get a great look at the machine. And it’s a weird, rather ugly contraption! It’s a bit like a stunted Formula One car with a windmill stuck on the back.

The car, and Dr. Muller, are in El Mirage. This is a dried-out lakebed not too far from Los Angeles, largely flat and perfect for wind-sailing. The test team shift Blackbird to a position where it will have a long, straight stretch with nothing in its way. All that remains is to wait for a decent breeze. Hours later…

Once the wind is finally up and the team is sure that the time is right, Dr. Muller straps in. The brake causes him some alarm, and he notes, “It’s slightly terrifying to not be able to push the brake in all the way.” But there’s no straight answer on how to stop the machine, as the experts aren’t too clear on the mechanism. Oh dear! The YouTuber quips, “Well, this is intense.”

Between Dr. Muller and the ground he will be racing over is nothing more solid than a mesh cocoon. He isn’t too impressed by the machine’s solidity, saying, “It feels like being in a rolling coffin… which has been shoddily put together. But I’m excited to try it, and I’m excited to survive.”

How will Dr. Muller know if he’s going faster than the wind? Well, there’s a “telltale” — a piece of string — flying at the front of the vehicle that shows him. If he’s matching the pace of the wind, it will droop down, and if he exceeds it, it will swing up and point at him, as though he had a headwind. So off he goes…

And the wind dies away. On the first run, it just never reaches a speed that allows the experiment to proceed: Dr. Muller is going to need a breeze of 9 or 10mph. For the second try, the wind rises quickly to 8mph — but then something goes wrong with the vehicle. The chain that links propeller and wheels falls off.

Attempt number three and Dr. Muller certainly gets the wind that he needs. And a bit more! The propeller goes crazy as the breeze gets into double figures. Cavallaro lets him know that he’s taking a huge risk by driving in such a stiff breeze. After a long wait, although the wind is “on the high end,” Dr. Muller decides the time has come for one last try.

As the sun drops below the horizon, the Blackbird starts to move. It gathers pace, faster and faster, until suddenly the telltale is pointing right at Dr. Muller. And it’s certainly not dropping either. The vehicle is for sure going faster than the speed of the wind. The only problem is figuring out how to stop it!

But as we mentioned earlier, this full-size experiment alone wasn’t enough to convince Dr. Kusenko, who went on to raise some objections — and agree to that $10,000 bet. After that, with the help of some colleagues, Dr. Muller went on to prove with scale models that everything was on the level and the design did indeed work as had been claimed. The YouTuber explained that this then had been enough for his fellow academic. He said, “Professor Kusenko has now conceded the bet and he transferred $10,000 to me. I want to thank him for being a man of honor and changing his mind in light of the evidence presented.” Dr. Muller said he planned to reward other science popularizers with the money.

Dr. Muller explained to Vice, “This is what I love about science. We only make progress when we’re able to not fool ourselves and not do things the way that they initially appear, but the way they really are. That’s what I’m really excited for: to show my audience, and the public more generally, how the scientific method can move us forward.”