Nobel Prize 2017 Edition, Podcast Transcript

Nobel Prize in Physics, 2017 — Special Edition

Hello and welcome to Physical Attraction, the show that explains physics, one chat-up line at a time. Today we’re hosting a special episode that’s going to focus on the Nobel Prize in Physics, 2017! This will replace our usual Saturday episode ’cause I wanted to get it out there while it’s still nice and relevant. As I’m sure many of you know, the prize was awarded to three people — Kip Thorne, Rainer Weiss, and Barry Barish. But really, it was awarded to the entire LIGO collaboration.

So, first, I think — a note explaining the prize — and then we’ll talk about what LIGO did and why it was important.

Alfred Nobel was a Swiss chemist, engineer, inventor, and businessman. The whole family had a long history in engineering: and Nobel’s father had made his money manufacturing, amongst other things, explosives. Before Nobel, the main explosive that was being used was gunpowder — but gunpowder is fairly primitive as an explosive, having been invented a thousand years before in China. Nobel worked on manufacturing new kinds of explosives, including nitro-glycerine which would later become the active ingredient in both dynamite and gelignite, both of which Nobel invented. Nobel was not a completely reckless boom-tastic guy — in fact, the whole point of both dynamite and gelignite was that they were much safter than raw nitro-glycerine, which pretty much explodes at a moment’s notice. He even nearly called dynamite “Nobel’s Safety Powder”, in part to get around several PR disasters where factories producing or storing his substances exploded. But, of course, safe explosives aren’t safe when they’re used intentionally.

The invention of dynamite, which was quickly adopted in industry and war due to far greater explosive power and efficiency than gunpowder, made Nobel rich. But it didn’t exactly make him popular with everyone. In 1888, Nobel’s brother died while visiting France — and a newspaper mistakenly published his (Alfred Nobel’s) obituary. (Mistaken obituary publishing does happen more frequently than you’d think, because people are under pressure to get the ‘scoop’ and not necessarily to verify the death — in fact, mistaken obituary publishing has, at least in legend, lead to at least one death.)

The obituary was not kind to Nobel. Normally I would just give the translation, but since it’s French and my pronunciation of French makes French people wince:

“La marchand du mort est mort” — the Merchant of Death is dead. That was the headline. Not a nice thing to read about yourself — or a nice thing to consider when you’re trying to calculate how you’ll be remembered. The article said that “Dr Nobel, who became rich finding ways to kill more people faster than ever before, died yesterday.” And this is generally reported as the turning point in Nobel’s life, because everyone likes a good story. Did it actually happen? You will find countless sources that repeat the story, but the actual obituary is quite elusive — if anyone listening knows of a copy, or the source for this story, I’d love to read it.

What is better documented is that Nobel was very engaged in the debate on what his weapons would do during his own lifetime, including a lifelong friendship with pacifist Bertha Von Suttner. Bertha von Suttner was a minor Austrian aristocrat who lived in the 19th century. She briefly worked for Nobel as a secretary and housekeeper and they became very close friends — naturally the historical gossip is that he might have been interested, but she went on to marry someone else. Regardless of whatever romantic drama was going on in the background, they remained friends. She worked as a novelist, writing books with an increasingly pacific tinge to them — and stayed in touch with Nobel even as she found herself one of the leading figures of the Austrian peace movement after publishing a famous novel, “Lay Down Your Arms!”, detailing the horrors of war. It’s a shame that people didn’t listen in the 1890s; the world might have been spared a pretty horrendous 20th century. And, as we know, of course, they’re not listening still.

In his letters to Suttner, Nobel expressed contradictory opinions about war and peace. He called war “the greatest of all crimes” but felt uncomfortable acknowledging his own role in helping the manufacturers of weapons. He fell back on a fairly common defence among scientists who manufacture weapons — the more powerful the weapon, the greater the deterrent to armed conflict. “My factories may well put an end to war before your congresses,” he wrote to Suttner in 1890. “For in the day that two armies are capable of destroying each other in a second, all civilized nations will surely recoil before a war and dismiss their troops.” Which, on one level, is sort-of true — the most powerful weapons we have now have rarely been used: but, on another, more pertinent level, has shown to be a total crock. And it conveniently allows Nobel to make millions off the manufacture and sale of weapons while still claiming some kind of moral fibre. It’s interesting to note that we still hear the same arguments about weapons today — and some of the similar justifications by scientists who find themselves working in the weapons business.

So whether it was seeing the obituary error, or his conscience — possibly embodied by Suttner — Nobel was obviously very concerned about his legacy, and how people would remember him. For this reason, he devoted 95% of his fortune to setting up the Nobel Prizes in his will. That money has since grown to be worth billions of pounds, dollars, whatever currency you like — ensuring the future of the Nobel prizes for a very long time — especially if they continue to be $1m per prize.

They’ve had an interesting history. Nobel’s original list of prizes were physics, chemistry, medicine, literature, and peace. Naturally the Peace prize probably owes something to Suttner’s influence. Then, later, the Swedish Royal Bank donated a large sum of money to the Nobel foundation to set up the prize for Economics. Which may have annoyed physicists who are often highly snooty about what is and isn’t considered to be ‘real science’.

This is a total tangent, but I can’t resist mentioning it — I recently listened to an episode of the Freakonomics podcast, which is great — you should check it out. The episode was entitled The Stupidest Thing You Can Do With Your Money, and their argument was essentially the following: don’t waste your time making investments where the fund is actively managed, as in, someone picks shares for you. These active management funds tend to underperform the market when you take brokerage fees into account. Instead, put all your money in an index tracker that rises and falls with the market in general. That way, you don’t pay fees, and you may end up making more money than the active managers who are betting on the success and failure of individual stocks. I mention this here because — I found the people they picked for both sides of this argument pretty hilarious. On one side, you have a Nobel Laureate in Economics. On the other side, they had Anthony Scaramucci. The Mooch. Somehow, they managed to interview him in the one-week window when he worked at the White House. I found this very funny. Anyway.

The Nobel Prizes quickly became some of the most prestigious awards that you could receive, and now they’re popularly seen as the Holy Grail of scientific endeavour. Of course, any scientist worth their salt will tell you that the most important reward is contributing something new to our understanding of the Universe and everything in it, but, you know: that’s a whole lot easier to say if you also have a Nobel Prize.
Marie Curie is the only person to receive Nobel prizes in both physics and chemistry, and one of a few individuals who managed to get two. The chemistry prize was for isolating radium, and the physics prize was for her work on radioactivity.

The rules for awarding the prize have morphed a little over the years. Nobel’s will originally intended that the prize was to be awarded ‘for the work of greatest significance that took place during the last year.’ But, obviously, this has a lot of problems. The main one is that it’s really very difficult to work out what achievements are going to turn out to be the most important. In the sciences, for example, some research seems initially exciting but then turns into a dead end; some research takes years to be appreciated as important; and some research is later invalidated. So there’s a famous example in Physics that some of you may remember — in 2011, they thought they’d discovered faster-than-light neutrinos. If the result was accurate, it would have turned a lot of physics upside-down. It took until 2012 for people to be conclusively sure that it was a mistake, although most people were pretty confident that it must have been. So what do you do — give them the Nobel Prize for a research topic that sparked a lot of initial discussion? If you insist on the “in the last year” rule, then you might miss the boat while you’re waiting for confirmation. And there was one particularly embarrassing case in 1926 — Johannes Fibiger claimed that he had discovered that a parasite could cause cancer in rats and mice, but it was later shown that he’d made a mistake in his experimental set-up and this was, in fact, false. Oops. So they’ve relaxed this rather stringent rule. Nowadays, it can take decades for people’s research to be recognized with a Nobel Prize. The physicist Chandrasekhar had nearly fifty years to wait to be recognised for his research into stars and black holes. Peter Higgs, who’s credited with the main idea behind the Higgs boson — his contribution to this particular field was mostly in the 1960s but he had to wait until 2013 to win the Nobel Prize as a result. In some ways, this helps to avoid controversies with research that turns out to be overhyped, or even false. For example — if they did this with the Nobel Peace Prize, we might have had fewer controversial nominations in that particular category. This long waiting period is particularly of concern because there is a rule that you can’t nominate someone for a Nobel prize after they’ve died; so, inevitably, some people are going to go unrecognized under this system. Personally, I don’t see what’s wrong with posthumously awarding it providing you don’t start trying to give one to Newton — how about it’s fine for people who’ve died in the last twenty years or so? But anyway, those are the rules.

And, of course, they have caused a lot of controversy. Specifically, this year’s Physics prize, which we’re now going to talk about, has caused some more controversy as far as the rules go. It was awarded to Kip Thorne, Rainer Weiss, and Barry Barish. But really, it was awarded to the entire LIGO collaboration. The prize is celebrating the detection of gravitational waves, but this took the efforts of the entire LIGO team. There is a rule that states you can’t divide the prize between more than three people. In some ways, it makes sense — if you could award it to hundreds, it might dilute the prize, and take away from the prestige of the individual effort. (Also, the cash gift would be meaningless, but that was always secondary to the real nature of the thing.)

The problem is that the way science is done has changed over the years. On the whole, it’s become more collaborative. This is a function of how much you know, of course — it was possible for Newton and even Einstein to just sit and think and deduce new things about the way the Universe worked. Einstein was working in a patent office when he came up with some of the insights that would later form the theory of relativity. Newton was holed up in his house while Cambridge was closed due to the Plague when he came up with many of his ideas. Similarly, in experimental physics, you have individuals who used to be able to set up apparatus in their garden shed, effectively, and make groundbreaking discoveries. But now, especially in experimental physics, lots of the work is done by big collaborations. Hundreds of people worked on the LHC in the ATLAS collaboration — and many people worked on the LIGO collaboration to detect gravitational waves.

The LIGO detector is 4km long. The ATLAS detector is 27km in circumference. Both of these experiments would not fit in your garden shed. More and more, scientific discovery is being done by huge collaborations of many scientists — so, as people have been pointing out for years, it’s about time that the Nobel Prize changed to reflect that story.

Not that the people who actually won the prize this year are undeserving. It’s just that there are plenty of deserving people who worked with them who, in the history books, don’t get an awful lot of credit. The Nobel prizes also need to answer for the fact that the last 127 physics prize winners have been men. Even though the gender bias in physics is bad, in academia is worse, and in the nomination process is probably also terrible, it’s still the case that 3% of Nobel Prize nominees over that time were women. That statistic alone tells you how bad the situation is — but even with that, you’d expect a few of the last 127 winners to be women if all was equal. Either way, it amounts to a lot of people not getting the recognition they deserve: or the sweet, sweet, Nobel cash. Gender inequality, and inequality in general, in physics is a huge, huge problem: as it is in education in general, globally. Beyond the unfairness for those who could have brilliant careers in science, how can we — as a species — hope to deal with the immense challenges we’re facing if we only let less than half the population help solve them?

Okay, with all that said — let’s talk about this year’s prize. It was awarded to these three scientists from LIGO for the detection of gravitational waves. Let’s talk about what they are, how they found them, and what it means for science.

Einstein’s theory of relativity makes two predictions that are important for gravitational waves. First, it explains gravity in terms of space-time being curved. This is a little mind-bending as well as space-bending, but the basic idea is that — if space-time is flat — then the shortest distance between two points is a straight line. If it’s curved, then that shortest distance is a curve. If gravity — the presence of massive objects — bends spacetime, then we can explain gravitational attraction by saying — objects still follow the shortest distance between points, but this path has changed. That’s why we see gravity act on objects in such a way as to bend their paths. Gravity bends spacetime, and this causes the path deflections in objects that we see.

This theory of gravity is probably not the final word in the argument, for reasons we’ll get onto in a later episode, but it’s helpful to understand gravitational waves. The other thing that Einstein’s theory predicts is that nothing can move faster than the speed of light — not particles, not light itself, not information, nothing. So — imagine moving a massive object. We know that this object is distorting space and time around it, bending the fabric. The further you get from the object, the less important that curvature change is — but it’s there in all of space, and all of time. The effects may be miniscule, but the fact is that the space and time around us is distorted by objects that are many light years away.

When the object moves, you can imagine that this curvature has to move with it — to reflect the fact that the location has changed. But nothing can possibly travel faster than the speed of light — so the changing curvature of the Universe, when objects move, must flow outwards at the speed of light. Whenever you move, you are emitting these ripples in space and time that spread throughout the Universe at the speed of light. Which is one of those ridiculously wild things that you can say when you know a little physics. If you’re alone — or in public, and you don’t mind being embarrassed — wave your arms. By the time you finish listening to this sentence, those ripples have travelled a long way. 1.5 million kilometres, in fact. Four times further than the Moon.

This is, in fact, exactly how electromagnetic radiation works too. You may remember we covered it in our episode on radiation, Unusually Hot. Electromagnetic radiation — which includes light, radio, microwaves, etc. — is basically just the Universe finding out that electric charges have moved. You move an electric charge, and the information about that motion propagates throughout the Universe at the speed of light, in the form of electromagnetic radiation. So it makes sense, in a lot of ways, that some similar effect might happen for gravity, too — which, like electric and magnetic fields, extends everywhere in space.

But gravity is a much, much weaker force than electromagnetism. You might feel like gravity is pretty strong when you’re trying to cycle up a hill, or whatever. But consider that the entire Earth is pulling down on you — an astonishing amount of mass — and you can still defy it by jumping up and down. By contrast, electromagnetic forces are much more powerful. This is why we don’t need a fancy LIGO detector and years of hard physics to study electromagnetic waves, compared to gravitational
waves. You can just open your eyes.

Gravitational radiation, or gravitational waves, has an amazing consequence, too — although really in a more philosophical than a practical sense. As the Earth orbits the Sun, it’s emitting gravitational waves, which carry away energy. This means that, due to this emission, the orbit of Earth around the Sun is gradually decaying. Given long enough, the Earth would radiate all of its energy away and crash into the Sun. But this won’t happen — because the Sun will expand in a few billion years and likely engulf the Earth anyway.

So since about 1916 and Einstein, we knew that there were probably gravitational waves all around us in the Universe. But because gravity is so weak, and the effects of spacetime curvature so small, it was difficult to see how we were going to observe them. But also around this time, we were learning more about the cosmos and some of the insane processes that go on there.

What we need, to observe gravitational waves, is something with a huge gravitational impact. An ant walking down the road on Mars is not going to do it — we need situations where whole stars are moving and generating these waves. So people started looking at the most massive — and gravitationally dramatic — things in the Universe. And they thought: what could be more interesting, gravitationally, than a black hole — an object so dense and so heavy that even light can’t escape from it?

They came up with an answer. Two black holes.

It’s a rare event that two black holes should find themselves close together, but since they’re powerful suckers, once they begin to approach each other, things get dramatic. Like any two big objects in space, the black holes will orbit around each other. Because their masses are much bigger, the gravitational waves that they’re emitting will be much bigger in magnitude. The closer together they get, the more powerful the gravitational waves are — because the orbit is getting faster, and because there’s a bigger gravitational effect.
As they emit these waves, the orbit loses energy. And this causes the black holes to spiral into each other — and, eventually, merge. Physicists new that these black holes merging together would be a very good source of gravitational radiation — especially in the time immediately before the merger, when they were very close together and still spiralling in. (After the merger, because the new super-duper big black hole is no longer moving, they don’t produce gravitational waves.)

So how can we detect this on Earth? In the 1960s, people figured out that this might be possible using something called an interferometer. The idea of an interferometer is a little tricky to explain, so here we go.

Light waves have peaks and troughs. This means that light can constructively or destructively ‘interfere’ with itself. You can imagine two light waves as being a little bit like ripples in a pool of water — when a peak meets a peak, they reinforce, but when a peak meets a trough, they cancel out.

The detailed experimental apparatus is a more complicated, but the basic idea of an interferometer is to exploit this property of light to make measurements of distance. Imagine two light waves that you set off from the same place, so that the peaks and troughs are all aligned. Then one of them follows a path that’s ever-so-slightly longer than the other. Clearly, the waves are going to go out of sync with each other. Maybe now a peak of one light wave aligns with the trough of another. If you then recombine them later on, you might see an interference pattern where the peaks and troughs are cancelling each other out. And then you’ve demonstrated that the light beams have travelled slightly different paths.

Clearly, this kind of instrument is extremely sensitive to changing the distance. In fact, if you just change the distance by a fraction of the wavelength of the light, you will be able to detect it, because the light pattern you see when you recombine the beams will change. And, using a different laser, you could make this distance a few nanometres if you wanted.

Now you can see the scale of the challenge facing the scientists at LIGO. They have a detector that’s four kilometres big, and they’re looking for changes in that length that are much, much, much smaller than that.

In fact, to find gravitational waves, they needed to build an apparatus that was sensitive to distance to 1 part in 10²². That means one in ten thousand million million million. If the detector was as big as the distance to the Andromeda galaxy, the distance LIGO are looking for is just one metre. That’s how sensitive the device needed to be — which is why finding the gravitational waves was such an amazing achievement by the collaboration.

The first observation of gravitational waves was made on 14 September 2015 and was announced by the LIGO and Virgo collaborations on 11 February 2016. It was caused due to two black holes spiralling inwards and merging — one of them was 36x heavier than the Sun, the other was 29x heavier than the Sun. Such a huge amount of energy was involved that — very briefly — the black hole merger was emitting energy at a greater rate than all of the stars in the observable Universe combined. (But, since that didn’t last very long, the overall energy signature is much smaller than stars.)
So there are so many amazing facts about this observation — I’ll just tell you a few of my favourites. First, not only did the waveform exactly match the theoretical prediction for this type of event, but it was actually the first black hole merger we ever knew about. Before then, we didn’t even know if it was feasible that black holes did merge together often enough for LIGO to see them. But since then, they’ve seen two more — so obviously it’s a lot more common than we originally thought.

Albert Einstein thought that gravitational waves might never be detected based on how tiny the effect was. The observation of gravitational waves confirms his hundred-year-old theory of general relativity once again: this was the last prediction of the theory that we had not confirmed by observation. And the distance change that the apparatus measured was really tiny. It changed the length of the 4km LIGO detector by less than a thousandth of the width of a proton. For scale, imagine — if you can — the distance to the nearest star outside the solar system, light years away. This is the equivalent of adding one hair’s width to that path, and being able to detect it. Stunning.

What’s more, the detection wasn’t just a vague “we saw something, guys!” — they could actually draw the gravitational wave. It’s exactly what you would expect from this event, and, if you look at it, you can see the frequency of the wave increasing as the black holes get closer together and start spinning around each other faster — and you can see what’s called the “ringdown”, the point where the black holes actually merge and gravitational wave emission slows down.

So this was a truly dramatic and fantastic observation. We waited decades to come up with a way of observing gravitational waves, and then LIGO spend decades refining their experiment to detect changes this small. Finally, after a hundred years of work of one form or another, we have direct experimental proof that these waves exist. And it’s opened the door to a whole new kind of astronomy. As they detect more and more events, we’ll learn more and more about the most massive objects in the Universe. The next big detection LIGO will be hoping to make would probably be two neutron stars merging together — this can also happen, and neutron stars would produce a pretty big signal, too.

The ceremony awarding the prizes will be on the 10th of December. The laureates will probably make a speech, but, if they’re not feeling talkative, there are always other ways to communicate. They could wave.

Thanks for listening to this bonus episode of Physical Attraction. There will be no episode Saturday, but the following Saturday, we’ll be back with another TEOTWAWKI special.

Time for the housekeeping!

We’ve got another taped interview coming up — this one with my Masters’ project supervisor, so get excited. For those of you who enjoyed our excellent discussion with Phil Torres @xriskology on Twitter, there are two pieces of information. The second half of our discussion will be released later on during the TEOTWAWKI series — it was very relevant to the discussion of AI, so I’ll put it out around the time of that episode in a few weeks. And you should all also know that his new book, Morality, Foresight, and Human Flourishing: An Introduction to Existential Risks — is up on Amazon. I’ve been reading it and it’s great so far, so you should all buy a copy, especially if you enjoyed his interview.

We have a new website — or, to be more accurate, we have a new URL. will take you to our webpage, that’s — so when, as I’ve ordered you to many times, you guys are telling all of your friends about the show, you can simply refer them to a much more memorable address.

Since we’re already overrunning, I’d like to do a few shout-outs to listeners and reviewers as well. Thanks to Jodi over on Facebook, and the others from the Podcasts We Listen To facebook group, for engaging with the show and recommending us to friends. Special thanks to everyone who’s reviewed us on iTunes. Super duper special thanks to all the Americans like Unframe of Mind who said they like my accent: I can’t help that it’s so unbearably sexy. I’d also like to shout out to AussieAsh for calling me a “great essayist” which really made my day when I read it. Thank you guys so, so much: writing and hosting this show is a lot of fun, but getting feedback is even better, and the more reviews we get the more likely it is that we can eventually achieve our goal of taking over the world.

I’m really keen on doing a listener questions episode sometime soon. So if there are any areas of physics you’d like to hear about, questions you’d like to ask that relate to the show, my personal life, etc. — there are plenty of ways to get in touch. You can email us at, you can hit us up on Twitter @physicspod, you can find us via the Facebook page (Physical Attraction) on Facebook, you can leave comments under the shows on our website at — there really are plenty of ways to have an impact on what we talk about. The more you talk to me, the better idea I get about the things you want to listen to, and the better I can make the show: it’s a feedback loop of a good kind!

Okay, enough admin, at long last. We’ll be back next week. Until then: carry on bending space and time.