For extremes month we have an extreme QnA! This week we're joined by astronomer Carolin Crawford, nanoscientist Colm Durkan, Haydn Belfield from the Centre for Existential Risk, and chemist Ljiljana Fruk.
In this episode
Meet the panel
with Carolin Crawford, University of Cambridge, Ljiljana Fruk, University of Cambridge, Haydn Belfield, Centre for Existential Risk, Colm Durkan, University of Cambridge
Our experts are astronomer Carolin Crawford, nanoscientist Colm Durkan, chemist Ljiljana Fruk, and Haydn Belfield from the Centre for Existential Risk, they're here to answer your questions and to bust some myths...
Chris - Let me introduce the fine panel of people who are going to be answering your questions for you this week Carolin Crawford. She's from the University of Cambridge and she's at the end of the scale which looks at things that are extremely big because you're a space scientist.
Carolin - That's right. Yes.
Chris - We can talk about the universe. Sitting next to Carolin, Colm Durkin who is also from Cambridge University. And he's concerned with the extremely small. I'm intrigued, down as small as what?
Colm - Small as you can get.
Chris - How big is that?
Colm - Just about the size of atoms and a bit bigger, so pretty small.
Chris - I'll hand you that. Thank you Colm. And Haydn Belfield a newbie on the program as well. Welcome to the show. You're from the Center for Existential Risk. What does that mean and what does that involve?
Haydn - So these are really big threats to international security, so things like a pandemic or a nuclear war or other happy things like that.
Chris - And you calculate or look at the likelihood of those things happening and ways to mitigate them and so on.?
Haydn - Yeah very much looking at ways to try and stop them because nobody wants that to happen.
Chris - Thank you very much Haydn. And also here is Ljiljana Fruk, who's a chemist at the University of Cambridge and also a keen cook. Soon soon to be restauranteur.
Ljiljana - Yes yes. And fortunately there are no big extremes in being a cook. Only extremes of pleasure.
Chris - Yeah extreme taste. Now everyone's got a bit of a myth to bust for so many. What's your myth then, Ljiljana.
Ljiljana - Well I was recently asked about dopamine because I work with dopamine. Dopamine is a hormone that is usually related to all pleasurable things, so people think that this is the hormone of pleasure, but actually it's a hormone of motivation, very important for learning.
Chris - Of course when one eats some delicious food
Ljiljana - Yes
Chris - You are motivated to seek more of the same, you will get a rush. I mean in your brain.
Ljiljana——是的。So it's a motivational hormone but then you have all kinds of other chemicals which are related, of keeping this happiness high.
Chris - And from very high to very low, very very small. Colm there must be myths abounding in the nano world.
Colm - Oh, there are more than you can shake a stick at, Chris. The one that really irks me is people have been saying for about 20 years that nanotechnologies would be able to make what they call nanorobots second go around the body repairing damaged cells and that is just complete twaddle, I’m afraid.
Chris - Why?
Colm - You basically cannot make things that do what you want at those length scales. You just can't. You can't make a little robot that can move around to any part of the body at will, and repair cells. We can do things that are pretty cool and that are close but not quite that. Not an autonomous machine.
Chris - Does anyone else feel saddened to hear though?
投资——我知道这是非常抱歉抱歉shatter your dreams.
Chris - I wanted to introduce Carolyn’s myth as well because you must have some massive myths with the universe at your fingertips.
Carolin - Yes but I'm just going to return to an old chestnut, having had this reflected back in me and talking to some schoolchildren this week, which is when they think of astronauts floating around in space I keep getting told there's no gravity in space and that's where they're floating and I just want to remind people there's plenty of gravity everywhere in space. And you know, astronauts aren't that far away if they're in the international space station, only four or five hundred kilometers further out. So yeah they've got reduced gravity but it's only reduced to 90 percent of what we have on earth. So the point is that they're in freefall, they're sitting in the international space station that is falling at the same rate the astronauts around Earth, so there's no kind of reaction force between the two and that's why they're weightless. So there's plenty of gravity in space.
Chris - I must admit I used to find that quite tricky to understand until I actually I met Dave Ansell who we're going to hear from later on in the program who showed me or introduced me to the experiment the Isaac Newton did, or his thought experiment about firing a gun, and firing a gun harder and harder and the bullet goes further and further but falls under gravity and eventually is going so fast that it is falling towards the earth all the time and missing the earth's surface. And as a result it's in orbit. And then I suddenly understood; Ah now I understand how it's under the influence of gravity it's always falling and falling and missing.
Carolin - Yes that's exactly what an orbit is. You're just falling towards something. It's just like it's deflecting your route and just continue curving around but you're not being pulled onto something.
Chris - Thank you Carolyn. And Haydn, what have you got for us in the myth department?
Haydn - So the myth I thought I could talk about today was we should be scared of the Terminator. The things we have to be worried about, I think the real risks aren't to do with some unstoppable evil robot thing that's marching towards you and has two hands and scary red eyes.
05:40 - Are all atoms the same size?
Are all atoms the same size?
Chris - Sure. Well this sounds like one for Colm to answer. How big are atoms? Les is saying are they all the same size? Presumably not.
Colm - So Les all atoms of the same material are the same size but different items of different materials are different sizes. So for instance the single smallest item is hydrogen and a single hydrogen is about one twentieth of a nanometre across.
Chris - How big is a nanometre?
Colm - So a nanometre is one billionth of a metre. So, to give you an example, if you take a hair - so a hair is about 50,000 nanometres across - the distance between atoms in a typical material is about a quarter of a nanometre, and the size of a hydrogen atom is about one twentieth of a nanometre. Then, if you go up to something like gold, so gold is about one tenth of a nanometre at its outer radius. But all gold atoms are the same. All hydrogen atoms are the same.
Chris - So, in summary then, all atoms of a type - or one specific element - are the same size, but, because there are nearly a hundred and twenty different elements, there's 120 atoms of different sizes?
Colm - Right!
07:15 - How big is the Earth?
How big is the Earth?
Space scientist Carolin Crawford answered this question...
Carolin - Tiny. Just about insignificant. That's the short answer. It depends what you mean by big. If you meant in terms of size, a dime to the Earth, well it's twelve thousand, seven hundred and forty kilometres across, which means that you could pack about a thousand Earths inside Jupiter; maybe a million Earths inside the Sun. We are truly insignificant. And in terms of mass, it's not much better. The mass of the Earth, it's sort of one three-hundredth of the mass of Jupiter; one three-hundred-thousandth of the mass of the Sun. So the Earth is tiny, whether you think in size or mass, and I'm afraid we are truly insignificant!
克里斯-说的事情不是insignificant though: the Moon is a very big presence in our sky. And I watched a really interesting documentary and it taught me something the other day - I hadn't realised this - which is that the side of the moon that faces the Earth is completely different from the side of the Moon that faces out into space, in terms of its surface appearance...
Carolin - That's right. The side of the Moon towards the Earth has a lot of those dark - we call them seas, or maria - but they’re actually just flat volcanic…
Chris - ...splodges. What we call man-in-the-moon-type pictures?
Carolin - Yeah, or they describe the bunny rabbit in the moon, if you see that. But the far side of the moon has only got one of those large mares, or seas, and most of it is the much lighter-weight sort of cratered terrain. So it is a big difference between the two sides.
Chris - So it really is a dark side of the moon, in terms of its mysteriousness!
Carolin - Well, actually, it's a lighter side of the moon because it has fewer of the seas.
Chris - And that’s true, and it gets more sunshine, doesn’t it?
Carolin - Yes, it does. Yeah.
Colm - It's odd because you'd expect... I would always imagined that the side of the moon that faces the Earth would have been more protected from collisions.
Carolin - Well that's certainly true....you get moons around Saturn, for example, I think it's Dione, which one side is far more cratered than the other side. An explanation for that is they think it's gone through a 180 degree twist in its history. And so one side was a lot more pockmarked by meteors, and then it got turned round, and it's got this weird dichotomy of its surfaces. I don't think that's the case for the moon.
How could a pandemic happen?
Haydn - Yeah that's right. So a pandemic is a really big disease, so a disease that would get everywhere in the world and infect a big percentage of the entire sort of world's population. So 100 years ago we had our last sort of really big pandemic, the Spanish flu. That killed more people actually than World War One, which had just came afterwards, and World War Two combined. So it killed between 50 and a hundred million people, so really devastating and yet not as well known as World War One and World War Two for some reason. And then more recently people will be familiar with things like Ebola or SARS or the swine flu bird flu. Lots of these things were animal diseases that hopped over into humans and sort of caused a lot of trouble. But that's not as bad as it could get. Right. Ebola hasn't killed thankfully that many people. Lots of doctors agreed that we're due a big pandemic flu that will affect lots and lots of people like it did a hundred years ago.
Chris - Why do they think that?
Haydn - It’s just happened very regularly throughout human history. And though we might be better placed in some respects, nowadays you know we all know to wash our hands and to sneeze into our arms and things like that. On the other hand we're much more interconnected. So if somebody ill gets on a plane in Heathrow they can be anywhere in the world in a few hours. One thing that we're particularly worried about is not just a natural pandemic, so a pandemic hopping over from another species, but someone cooking up a far nastier pandemic. There's some risk that something might escape from the lab or be deliberately made and released into the world. What we can do, nevertheless, is we can put in place various measures to try and reduce the risk. So better bio-surveillance around the world or better regulation of what is allowed to be published or what things you're allowed to order online.
What's the smelliest chemical?
Ljiljana - Well there are many contenders but no matter which molecule we take, it will definitely contain some thiols. Thiols are sulphur compounds and there are two contenders. One is thioacetone, it's a very small molecule that has a sulphur in its structure and the other one are mercaptans which also have thiols and they're the smelliest compound. The first time when thioacetone was made at the end of the 19th century, people had induced vomiting and they felt nauseated.
Chris - What, when they smelled it?
Ljiljana - Yes, in the range one kilometre around the chemical facility where this was made.
Panel - [groans]
Ljiljana - So it is an extremely potent and smelly compound and skunks, for example, have lots of thiolated compounds...
Chris - They make Methyl mercaptan, don’t they?
Ljiljana - ...Yes
Chris - Because it’s similar to the stuff that asparagus gets metabolised to. When you eat asparagus and have asparagus wee…
Ljiljana - Yes, it’s the same chemical. And the problem with thiols is that they are actually the products of decomposition of proteins. You will find them in cadavers or in all these non-appetising things. And so we are evolutionary primed to feel a little bit of...
Chris - Steer clear because it could be bad?
Ljiljana - Yes! And there are some other compounds which don't have thiols, for example lots of amines…
Chris - Eww a fishy smell.
Ljiljana - Yes, and one of the worst that I worked with was cadaverine, as the name says it a product of cadavers…
Chris - It smells like corpses?
Ljiljana——是的。你使用它在化学合成because it's very useful to make some amines. And when you use it you can get rid of the smell, so you get out of the lab and people just steer away from you and you know you get used to it already.
Chris - I remember I worked in the lab once where we would add one of these particular sulphur compounds to gels that we were running when we were studying proteins. The lab head would come in and sort of sniff and goes, “it smells like an 'All-Bran' research laboratory in here today”. It does smell like someone's had a very bad bout of flatulence and it's really, really unpleasant!
Ljiljana - Absolutely. And what is really curious, then again, is that we also have lots of foodstuff that is smelly and we like. Just imagine cheeses…
Chris - Yes, french cheeses!
Ljiljana - Or this fruit, durian. I don't know if you ever tried that?
Chris - It's actually banned from taking it indoors in some places like in Singapore. You're not allowed to say that inside because it's a weapon.
Panel - [Laughs]
Chris - Empties a residence fast but it tastes fantastic.
Ljiljana - And some neurologists were actually exploring this, why do things which we are evolutionary primed not to like still tastes so well? And they found something which is called the backwards smelling reflex. That means first you basically smell and you have these nauseous feeling but then you activate some receptors which give you a huge amount of pleasure. So there is a balance.
14:08 - Sending a balloon to space
Sending a balloon to space
with Dave Ansell & Omar Gad
We're putting some screams into space, to test the old claim that "in space, no one can hear you scream. To find out how, Chris Smith spoke to Dave Ansell and Omar Gad...
Omar - I actually am very passionate about electronics and how they've advanced over the years. And the thing that made me want to do this the first time was exposing, you know, these types of electronics that you can actually buy anywhere, to harsh environments, such as space, and see how they fare. I think that that is a very good indicator of how well we've progressed in the side of electrical engineering and electronics in general.
Chris - So you thought you'd get in touch to see if we wanted to come on your balloon with you. So let's let everyone in on the secret, what we decided to do. I suggested to Omar, you know you've heard this claim: “no one can hear you scream in space” but actually we could test the physics of this, of how sound is transmitted through a gas and actually work out whether or not as the gas gets thinner with altitude the sound does disappear. Then we thought, how do we actually test this? Which is where Dave got involved. So what did you think when you heard us saying we're going to try and do this? What was it that first went through your mind? Oh my goodness is that Chris Smith again?
Dave: That was part of it! But I mean, so basically we need a way of producing sound and a way of recording that sound. I did have a long diversion into trying to produce horns of various different types to take up into space, but we’re going to - let's go for the simple thing. We've got a loud speaker and a microphone. You play something. It could be your scream. So if you want to send us in a scream, you can get it played in space.
Chris - Well actually Dave, Mark Litton sent me one yesterday. Would you like to hear Mark's scream? This is what he would like us to send into near space for him. I'll see if I get this to play.
Mark - *scream*
Chris - Well that's Mark's contribution to our effort. And actually Sue Marchant then heard that we were doing this Sue Marchant from the BBC eastern region. And she said “well I want to be part of this” and so she's done us a scream. You better hold onto your hats for Sue’s scream! Here it is.
Sue - Oh! Did you hear that? Ow! Did you hear that? Ooow! I bet you heard that!
Chris - So there you go. So we've got a range of screams we could put on there and you've done some as well.
Dave - Yeah. Sue's is particularly nice, it’s got a range of volumes, so if we get the volume wrong...
Chris - But tell us about the apparatus, first of all, that you've designed, because the key thing here is if we just put a speaker in a box then the vibrations could come out of the speaker transmit through the box to the microphone, which is also stuck on the box and then it would just cheat and that wouldn't test sound transmission through air. So what have you done to get round that?
Dave - So basically we've tried to isolate both the microphone and the loudspeaker from the box. - *background scream* - There you can hear Omar’s scream, in fact, that we’ve been testing it with!
Chris - He's just plugged it in. So basically we've isolated the microphone and the speaker so we know the sound can only go through the gas.
Dave - So they're both hanging on springs to damp out any resonances you might get on those springs.
Chris - Dave’s got a picture of this on the internet and there’s also a video of this. So Omar you've written the software. Because we're sending a computer to do this, because we're actually going to do it properly and every increment of altitude we're going to make a recording right?
Omar - Yes. Yes. This was just part of the test script and making it run every five seconds, but in the real scenario we'll probably gonna make it run every five minutes. So on here as well we have a G.P.S. tracker, as well as a pressure sensor and that will be able to also calculate the altitude. And then we'll be able to feed that information into the main micro-controller that will then couple this sound that we recorded with how high it was when the sound was played.
Chris - So we're going to basically be able to plot a graph of how loud it is with increasing altitude and we will see, therefore, we can relay that the pressure, and we can see how the sound is going to change, if it does. You're using a Raspberry Pi computer to do all this. How do you know it'll survive at 3000th of the pressure you get at the surface? Dave, how can we mitigate against that?
Dave - So I got a vacuum pump in my shed. It's not a perfect vacuum pump, it won't get quite that low but I've pumped it down to maybe 70/80 millibars and everything seems to work fine.
Chris - So you've got the rig there with a mechanically decoupled microphone and speaker and the Raspberry Pi stuck on the outside. You put that in a vacuum chamber and you had Omar screams running through it. So is that what you sent me? Because you sent me that audio this afternoon, is that what you sent?
Dave - That's what I sent, yes.
Chris - Because I've got your two test runs here, so I can play this one and you can talk us through what we're hearing. Here's the first one that you sent me.
*scream noise*
Dave - So that is probably at full atmosphere.
Chris - That's that's a ground level.
Dave - Yeah.
Chris - And then this was the second one you sent me.
*White noise sound with quieter scream*
Dave - You can hear the air being pumped out, that it's at a much lower pressure and you should be able to hear that it’s much quieter as well.
Chris - Yeah it was a much more threadbare scream and that's not because your apparatus is falling to pieces?
Dave - Hopefully not. It should be that there’s just basically less air their, so as the loudspeaker moves, it moves less air, so there’s less air moving inside the box, so you get less forces on the microphone.
Chris - And of course, we're recording all of this on the way up and then the balloon gets to 120,000 feet. How do we get the balloon back?
Omar - Because there is less air pressure there the helium in the balloon will force the balloon to actually expand and expand and expand until it pops and falls back down to Earth.
Chris - How do we know where it's going to come down?
Omar - So we have a receiver on the ground and a transmitter up in the box on the balloon.
Chris - Because I want my computer back!
Omar - Obviously we'd be able to use that information to actually literally chase it using a car.
Chris - Super! When's the balloon going up?
Omar - Twenty ninth of June.
Chris - It's definitely gonna be then is it? We're gonna do it then?
Omar - Well yes. Most likely then. I keep checking the weather every day to make sure that the weather is as good as possible for the launch. And it does seem that it will be that day.
Dave - The worry is that if the wind direction’s in the wrong direction it ends up in the middle of the sea and then we don't get any data back at all!
20:41 - What does nanotechnology mean?
What does nanotechnology mean?
Colm Durkan answered this question...
Colm - OK. Thanks Deirdre. So how long have you got?! Nanotechnology is, I'm gonna give you the formal definition and then tell you what that actually means because we scientists love complicated ways of saying really simple things. Basically nanotechnology is the ability to both make and characterise and use things that have nanometre dimensions. A nanometre is one billionth of a metre. And what happens is, the reason why nanotechnology exists as a field is that when you have any piece of material that's got those sorts of dimensions that you can measure in nanometres then its properties become different to larger bits of the same material. The simplest example, if you've ever looked at a stained glass window you'll see all these different colours in it and in many cases those colors are all made using the same material which is gold. Artists in medieval times did all sorts of experiments or they fiddled around with all sorts of chemicals because they had nice colours and they realised that just by changing the way in which they mixed certain chemicals together they could change the colour just by basically waiting for a little bit longer. And you know so for instance, gold when it's in nanoparticle form. So when it's a few nanometres across a lump of gold is no longer gold in colour it can be anywhere from green, red, blue, yellow. Take your pick. It’s purely down to its size and that’s just one example of about 100 that I could give you.
Chris - Ljiljana go for it.
Ljiljana - I wanted to ask you. You said that colours are changing. What else changes when you go the Nano. Like conductivity or something else?
Colm - Yes. Yes. So what we do in my lab is, so we first of all, we try to understand why the properties of materials change and then we make them do what we want and then we try and do something useful with it. So the sort of things that change are electrical properties if you take gold as an example it does so many things. It's a really good conductor of heat and electricity. If you make it small enough as a nanometre size then it can become an insulator. So you've got colour, chemical properties, change electrical properties change and so on.
24:09 - The Extreme Quiz
The Extreme Quiz
Who will be this week's big brains: astronomer Carolin Crawford and nanoscientist Colm Durkan, or the Centre for Existential Risk's Haydn Belfield and chemist Ljiljana Fruk...
克里斯-现在我们总是试着做一个小测验our panel of people when we do this. And they're competing for a prize beyond price, which is the Naked Scientist Big Brain of the Week award. And there are three rounds, and because this is our extreme month where we have a series of programs dominated by the theme of extreme things - this is an extreme Q&A show - and so this has some kind of relevance to this quiz, where everything is to do with extremes. So our two teams are Corm and Carolyn, and Haydn and Ljiljana. Round One is extreme weather. Are you ready, both of you? You may confer. This first question: the most rain recorded to fall in one minute was one hundred millimeters. Is that a science fact or a science fiction?
Carolin - Gosh. It feels like we've had most of that over the last week actually. Shall we say fact?
Colm——我想说,有可能在的地方in India, yeah.
Chris - I'm really sorry, actually it's false. The most rainfall in a minute was 31.2 mm - that's 1.23 inches. It was recorded in 1956 on the fourth of July at Unionville in Maryland, in America. Okay. Unfortunately, zero for you. Haydn and Ljiljana, see if you can improve on a score of zero. The coldest temperature ever recorded on Earth was minus 60.3°C. Is that a science fact or a science fiction? What do you think?
Ljiljana——我认为这是一个事实。I think it was even more than minus 60.
Haydn - Well can't we get things incredibly cold in the lab? So couldn't it be even lower?
Chris - Just to clarify, this is naturally, like in the natural world.
Ljiljana - But good thinking!
Haydn - I was thinking, because it’s the extreme month it might be extremely hard or extremely tricky questions.
Ljiljana——我认为这是一个事实。它能得到前tty cold. But I don’t know, you are extreme risk.
Chris - You’re saying science fact?
Haydn - I’m gonna go with...yeah.
Ljiljana - No!
克里斯-好了,零势均力敌。实际上coldest temperature recorded was even colder than the minus 60.3 - it was minus 89.2°C, minus 128.5° Fahrenheit. That was recorded in July 1983 in Vostok, Antarctica. Right, back to Colm and Carolin. See if you can improve on your score. This is Round Two: extreme fact or extreme fantasy. This is an example of someone who's extremely dedicated: the Schmidt pain scale was created by allowing venomous things to sting and bite people, and then record their reactions. Is that science fact, or is that something I made up?
Carolin - Ooh.
Colm - Well I think that's correct.
Carolin - Oh you think it's correct? I was going to say it’s fantasy. Well I'm happy to go with Colm’s decision here.
Carolin - That was the right decision my half. Go, excellent, well done.
Chris - Yes, you were right Carolin, that's right - right to listen. It's true. In 1983 entomologist Justin Schmidt famously came up with his Schmidt pain index. He rates the pain of various insect stings and bites by letting them sting him. For each he also provides a nice colourful description. So rated 2 on his pain index is a wasp sting; that causes a pain that he says is hot and smoky, almost irreverent, imagine W.C. Fields extinguishing a cigar on your tongue, he says. Level 4 is apparently the top of the scale. Although Schmidt says the pain from a Nicaraguan bullet ant is 4 plus! And it’s like walking over flaming charcoal with a three-inch nail embedded in your foot. Anyone here had any painful brushes with nature? Anybody?
Ljiljana - Well I had a wasp sting. It wasn’t...
Chris - But that's that Schmidt scale 2!
Ljiljana - I know, but it didn't feel like this! He was very poetic.
Chris - Very poetic or potent? I got stung by a Portuguese Man o’ War jellyfish. That was pretty painful, I have to say, I noticed that. I won't be repeating the experience either. Right, so you've got one point so far, so Carolin and Colm go into the lead, score of one. Over to Ljiljana and to Haydn, here you go: this is your question, an example of someone who was extremely dedicated. Greenland's only railway was built to move a meteorite. Science fact or science fantasy?
Ljiljana - This is so crazy that it’s probably a fact.
Haydn - Greenland’s only railway. Hmm.
Chris - Or did I make that up?
Haydn - I like that. I hope it’s true.
Ljiljana - I mean, you would expect meteorites falling into some really deserted places, and then...
Haydn - I presume it's so big that they needed to move it to the coast, or something like that?
Chris - What are you going for?
Haydn - Carolin is looking very…
Ljiljana - She knows!
Chris - Fact or fiction?
Ljiljana - Fact.
Haydn - I think fact.
Chris - Carolin sounds like she knows more about it than I do, but I'll read you what's written here. It’s Arctic explorer Robert Peary, who located a 31-ton lump of metal that local Inuit had been using as a source of iron for their harpoons and knives. It was the third-largest iron-rich meteorite recorded on Earth. He sold it for 40,000 dollars to a museum in New York, but first he had to get it on a ship to get it there. Unfortunately it was nowhere near where the ship was, so the only way to get it to where he could dock a boat was to build a railroad to put the meteorite on there, and then move this 3.4 by 2.1 by 1.7 metre chunk of iron to the ship, and it's now called the Cape York meteorite.
Ljiljana - And I can tell you he was full of dopamine, because he had a huge motivation.
Chris - Well he trousered forty thousand dollars. I suspect it was a lot of money in those days, wasn't it. Okay, one each, level pegging into Round 3: extremely trivial. Colm and Carolin, extremely stupid is your question. Ostriches’ eyes are bigger than their brains. Science fact or science fiction?
Carolin - I suspect that…
Chris - ‘Eye’ suspect, I like that.
Carolin - See, you’ve got to try and second guess, it's not the answer you expect.
Colm - No. I mean, I would expect...
Carolin - I think it’s fiction.
Colm - That's funny, okay. I would expect it's true because they're really quite stupid, and they have big eyes.
Carolin - I’m just wondering if it's a double bluff. Because we expect it to be true, it’s actually not.
Colm - That’s too clever for me.
Chris - So where are you going to go go, science fiction or science fiction?
Colm - I'll listen to you this time.
Carolin. Oh dear. Well I'm saying it's fiction, so if we fail I'm sorry Colm.
Carolin - Oh no!
Chris - Actually, this is true. An ostrich brain - thanks to a Turkish publication I found, I checked the diameter and the various measurements - the dimensions are six centimetres by four centimetres by four centimetres, so the volume of the brain’s about 96 cubic centimetres. The eyes are actually four centimetres diameter. So the volume of a sphere being four over three pi r cubed, that means the volume of the eye is more than the volume of the brain. About 125 or so cubic centimetres each eye, and they've got two of those, so most of an ostrich’s head is actually its eyeballs, there's very little brain there. They're allegedly endowed with these enormous eyes in order to be able to see well in the dark so they can escape predators. They're not very good at that, though, because when something does frighten them they just run around in circles. So actually they can see what's going to kill them very well, but they're not very good at escaping. They are very fast, though, so there is that. Right. It's all on this one, you two. If you get this then we don't have go to a tie breaker. Are you ready? Okay, going to have to give your answer quickly to this one. Stewardess is the longest word you can type with only one hand on a keyboard with the same hand.
Haydn - What about stewardesses. Surely you must be able to do that with one hand?
Ljiljana - I’ll leave it to you.
Haydn - I think it's not true because you can do stewardesses.
Chris - That was my sneaky one. Indeed, stewardesses is the longest word that you can type with only one hand. All those letters are on the left hand side of the keyboard, the E is sneakily there as well. So stewardess, yes you can type that, but stewardesses is up for grabs, and that's the longest one you can do with one hand. Bonus point, then. Can you tell me: what is the longest word you can type with just one row of a computer keyboard? What do you think?
Haydn: ‘Qwertyuiop’, what would that be…
Chris - Oh no, it's got to be in the dictionary! I’ll let you out of your misery. It's typewriter. Isn't that appropriate? It's all on the top line of the keyboard. Well done, our Big Brains of the Week award goes to Ljiljana and Haydn. Very well done, give them a round of applause. Very well done. We’re impressed with that.
What's the most toxic chemical?
Ljiljana - Interesting. Again, plenty of candidates but the most toxic chemical is basically a natural product. There are some chemicals which were made in the lab which can be very tricky but the most toxic according to some scales is the botulinum toxin which is funnily enough used in Botox. But there is a particular scale which is used and it is a lethal dosage that kills 50 percent of subjects. And this is in the case of botulinum toxin, 1 nanogram per kg. That means that you need very low amounts to cause really toxic effects. So it's kind of you know it is a little bit ironic that you can basically use it also in cosmetics today. When we think about synthetic compounds, there are some neurotoxins that have been made. And you know when Haydn was talking about some dangerous stuff and some risks so there may have been lots of chemicals that have been made that are extremely toxic. One of the most toxic ones is the chemical called VX. It's a synthetic poison, a nerve agent. So it basically inhibits signaling between denounced it will cause lots of muscle convulsions and heart attack and it will really kill people instantaneously. It's still less toxic than botulinum. So you would need around three micrograms of this compound to kill the person which means nature has made the most toxic ones.
Chris - I've got something I think can challenge that, Ljiljana. I said there's someone who got in touch and I think that this lady's cooked up something that could give you a run for your money! I just want to read you this letter and you can as the chemist on the team you can tell us what you think of this...
So this is from Mrs. E. Naughton and she's written in and she says she she likes the programme, but she's also a fan of cooking and she was making some stock. She's boiling up some Lamb bones in three independent pots. She didn't have a lid for one of them. So she found instead a frying pan. That was a bit smaller than the top surface of the saucepan, put two wooden skewers across so that the steam could still escape and put the frying pan bottom down on top of the pot because the frying pan was slightly smaller than the diameter of the cooking pot so that way, acted as a lid. But it was a frying pan. She went away for a couple of hours leaving her stock simmering came back coming down some other jobs and she said after two hours of boiling the other pots had this lovely honey-coloured stock in them, delicious. The pot with the frying pan on the top now had this charcoal black or dark green substance. The pan was black on its bottom although it did wash up fine later, I'm pleased to hear. She says she's kept this liquid separate. So should I use it, she’s wondering, or should I chuck it away?
Ljiljana - You know considering that there is a control experiment that she has done and this is this honey colored wonderful stock I would say probably chuck it away.
Chris - What do you think is in it?
Ljiljana - So I'm suspecting that the pan was made of copper.
Chris - She said it was a copper-bottomed pot.
Ljiljana - So it's probably copper hydroxide or copper carbonate.
Chris - So why has it come off?
Ljiljana - The copper has oxidized. So the copper pan is made of metallic copper. Copper very easily oxidises. So I think the combination of steam and a combination of maybe some herbs that she has put and some aromatic compounds that were boiling, oxidized the copper, made copper II compounds - carbonate or hydroxide. There are not cases of direct poisoning with a copper II compounds, but there is a certain lethal dose there. But everybody is more or less sensitive to some of the copper ions, so I would just say, chuck it away.
Chris - Probably good advice. It probably wouldn't taste great, and it didn't look that good either compared to what else is on the plate.
Ljiljana - Yeah there is that the interesting thing about food. Usually it does look very good and tasty and then you should eat it. And if it doesn't then yeah think twice.
36:40 - How bad could climate change get?
How bad could climate change get?
Haydn - Yes. This will be something that people are really familiar with I am sure, for over the last few months, of the Extinction Rebellion protests and people like Greta Thunberg really raising alarm about this issue.
The simplest answer is we don't really know, but that's something to be worried about. We know that the definite effects of climate change are going to be really catastrophic for people around the world. And there’s a moral element to it in that the people who have contributed the least, who have burnt the least amount of stuff, are going to suffer the worst consequences. So we should do something even on the most likely outcome.
But what climate scientists do, what they look at is they model different scenarios. And the IPCC - the Intergovernmental Panel on Climate Change that people will be familiar with - gathers all these together and looks at what are the most likely outcomes of different scenarios? So if we pump this amount of carbon dioxide into the atmosphere will we get this amount of heating, what might the effects of that be?
But the problem is that they mostly look at sort of the most realistic outcomes. They don't pay as much attention to the very unlikely outcomes of five degrees or over. And if we were very unlucky, we hit a few bad feedback loops. So that's things like permafrost up in the Arctic melts and releases a whole load of methane, a much more powerful greenhouse gas. You might get sort of much more warming than you might expect. So the worry is for something greater than 5 degrees that it might be very bad indeed. It might affect the ecosystems that we rely on. So that's the sort of natural world that produce clean water and pollination and things like that for us. It might affect our ability to grow food or to have clean water and it might spark conflicts.
So the Syrian war and Sudanese war, it’s often said they were the world's first climate conflicts. So the worry is that if we are very unlucky and we have sort of very runaway climate change of over five degrees of warming, that you get huge amounts of people having to move because they literally can't live where they used to live.
What's the biggest star?
卡罗琳,最大平均尺寸,现在我们说话ing diameter of stars, the most reliable estimate I can give you is a star that's just short of 4000 light years away. It’s a red supergiant called VY Canis Majoris and its diameter is somewhere between about fourteen hundred to two thousand times the diameter of the sun, which means its volume is three billion times the volume of the sun. And you know these are all large numbers but...
Chris - That’s a big star, that could give Justin Bieber a run for his money
卡罗琳——好吧,如果锻炼,如果你罗und its circumference at the speed of light it would take you six hours to go once round. Whereas if you did the same thing with our sun it would just take you a hundred forty five seconds. Now, so that's a lot bigger but there is an interesting question here is, how do we know the diameter of this star? Because even when you look through telescope most stars just look like points. A star like this that's big and relatively near you can sometimes resolve the disk and even measure the angular size of the disk, you know how far away the star is, you got a triangle and you can measure the width of the disk. But once further away you can't actually see the disk and you have to be quite clever so you have to do some physics to infer it for most of the stars. So even though there could be some stars which may be larger, the most reliable estimate is the VY Canis Majoris at the minute.
What is the doomsday clock?
Haydn - I love the Doomsday Clock. I think it's a great, great symbol of our impending doom or what we can do about it.
Chris - You’re an optimist!
海顿-侯末日钟是一个时钟r hand on twelve-midnight and then the minute hand is showing, is it 15 minutes to midnight? Is it 10 minutes to midnight? Where if it's on midnight then everything's gone very badly indeed. It was set up by something called the ‘Bulletin of Atomic Scientists’, who were a group of people who worked on the bomb in the second world war and felt pretty bad about what they had brought into existence. Oppenheimer famously said after the first atomic bomb test, “I am become Death, the destroyer of worlds.” They were feeling pretty bad about what they did. They thought they should warn people about the dangers of this new weapon so they created this great visual representation of risk and they've been doing it for the last 70 years.
It was the closest it's ever been to midnight, two minutes to midnight in 1953, when the first really big new type of nuclear weapon, the thermo-nuclear weapon, was exploded and then it was very close, of course, again in the Cuban Missile Crisis… Very close again in the early 80s but then at the end of the Cold War it was put back over 10 minutes because things were getting safer. There was a reduction in tension but then over the last couple of decades they've added in other threats to the world. Things like climate change and things like new technologies. So I've got a question for you, what do you think the time currently is?
Chris - Five-to-twelve? Ten-to-twelve? I think climate change is huge. Climate change coupled with human population expansion is a huge risk. I'd say it's five-to-twelve.
Haydn - What do you think, Ljiljana?
Ljiljana - I'm a little bit more optimistic so I we'll go eleven-to-twelve…
Haydn - Well unfortunately it's much worse than you think. It's currently set at two-minutes-to-midnight, which is the joint closest with 1953 that it's ever been.
Chris - And is that attributable to the risks I'm suggesting? Things like population climate change and so on.
Ljiljana - And is it also accounting for new technologies that could help us to resolve this?
Haydn - Yes. I mean it's not exactly a strictly scientific thing but they are trying to account for all of those things. It's because of our new biotechnology, things to do with artificial intelligence, machine learning but mostly it's been driven over the last few years by how things have got worse in the nuclear zone. It was set at two-minutes-to-midnight last year and then this year they didn't move any closer to midnight but they didn't want to say everything's fine, everything's holding steady. They've described it as the ‘new abnormal’. We're currently living in the new abnormal and desperately need to get that minute hand further away from it.
43:52 - What's a parsec?
What's a parsec?
Carolin: Well yes that's infamously wrong because the parsec is a measure of length and there Han Solo was using it as a measure of time. So that was a big faux pas but it's a measure of length, it's three point two six light years or about 31 trillion kilometres and it comes from the way we measure distances to stars. So it's using the method triangulation or parallax, where you look at the way a relatively nearby star is displaced relative to the background when you observe from one side of Earth's orbit and then you know six months and 300 million kilometres later the other side of Earth's orbit. And if that shift against the more distant stars is one arc second an anglicised one arc second then that star is one parsec away. And just to say how small one arc second is, it’s a measure of angular size, that is the size that a pound coin would subtend at a distance of four kilometres. So it's a really tiny amount. So parsecs measure distances to stars but they start to get unwieldy before too long. If you want to think about distances in the galaxy we talk about kilo-parsecs, so thousands of parsecs. So like the center of the Milky Way is eight kilo-parsecs away from us, Andromeda galaxy, our nearest large galaxy, is 800 kilo-parsecs away, but after that, actually we use mega-parsecs, so millions of parsecs. So m87, which was observed by the event horizon telescope, the image of the event horizon around it, that is sixteen mega-parsecs away. So it's not a particularly useful unit of distance given that we have to go into mega and kilo quite soon, but it's more as, I say, more historical because of that original way of measuring distances to nearby stars.
Chris: If all of the bodies in the universe are in motion because our star is moving around the center of our galaxy, our galaxy is moving around as part of a big cluster of other galaxies, how do we kind of keep track of where everything is? Because presumably it's all changing over time and it's all changing all the time?
Carolin: Well now if you think about modern satellites like the gaia satellite who do all this meticulous measurement and motions they actually use a reference frame which is way external to our galaxy. They'll use that the grid of very distant quasars which are so far away we're not seeing their motion relative to us so that is a fixed grid that is external to our galaxy.
Chris: By referencing that, even though things locally might move around a bit, we've got those fixed points to rely on?
Carolin: That's right. That's the nearest we can get to fix points. And you know now we can measure things to within about 10 micro-arc seconds or that's about the equivalent of your pound coin, not a distance of four kilometres, but on the surface of the moon. So gaia satellite is refining all these distances to fantastic accuracy.
Chris: I think Gerry Gilmore said to me it's got a giga-pixel camera on it or more isn’t it. I mean that's some camera; it's eye watering detail that they're getting isn't it?
Carolin: And the amount of data that they get is... just handling that is a huge challenge.
47:05 - What's the most explosive chemical?
What's the most explosive chemical?
Ljiljana - So the most explosive chemical was made in 2011 in the lab. Never went out of the lab it was made in a special chamber and it's called azidotetrazole. So that's a molecule that has 14 nitrogens in its own structure, and because of these constrained nitrogen bonds it's very explosive.
Chris - You're saying it's just 14 nitrogen atoms linked together?
Ljiljana - It has some carbons in the middle; two carbons only. So this is like a really huge amount of nitrogen and these nitrogens of course want to create stable compounds, which is nitrogen gas. Some scientists said that this molecule could explode even if you look at it, because you know it really reacts on a tiniest amount of pressure.
Chris - How did they make it then?
Ljiljana - So they had a specially designed chamber which is really you know anti-static. And you know it can contain huge explosions and they made a very small amount of grams. And the scientific paper is really funny to read because every single you know figure has a notice like this should not be attempted because every intermediate step is extremely explosive. So this was like just to prove the point that you can make it. But of course if you would think about commercial explosives we know TNT is pretty explosive but actually there is another version similar to TNT, it’s TATP which is called Mother of Satan.
Chris - Oh wow.
Ljiljana——是的。So the name is very descriptive. It's even more explosive than TNT and some other explosives. So you know pretty interesting stuff. I think chemists actually have always had a little bit of a desire to make the next explosive things and then as we all know nitroglycerin was actually also in some way responsible for Nobel Prizes because this was one of the first explosives that was made by Alfred Nobel and he put all the money that he earned by selling this explosive into the foundation that gives the Nobel prizes. So this is one thing how explosives can also give something back to science
Chris - Just as well that they did!
What's physics like at small scales?
Chris - Here's a question for you Colm: does physics become unusual at a small scale? It’s kind of getting at quantum mechanics isn't it? So when you're playing around with individual groups of atoms at the scale that you do what actually happens to them that would be different than if you're dealing with something at the scale that we can see like a coffee mug or a knife and fork?
Colm - Well there are so many things. I mean, at a very basic level when you make something small enough, so let's say you take a particle that’s just a few nanometres across. You can do a similar calculation you can figure out how many of the atoms in it are on the surface and how many are inside. And if you think about it atoms inside a material are surrounded on all sides by other atoms so they are energetically in stable states. They’re in bonding configurations that are low energy and stable whereas atoms on a surface are not surrounded on all sides. They basically have higher energy, but you also have quantum mechanics coming into play as well. And what that's all about is we think of the world around us as comprising particles and waves. So we think of light as being a wave and we think of matter being made up of particles that are hard solid objects. It turns out that that way of looking at things while it's very intuitive and it makes sense and fits in what we see everyday, that breaks down when you're at atomic dimensions and below. Even things like simple electrons do not actually behave like solid particles when they're moving through material. So when you've got an electric current flowing through something it's made up of all of these little particles, which under the right conditions, can display wave like characteristics. Which means they have interference, you know, you can get electrons communicating with each other over vast distances because of this wave nature. In nanotechnology what we what we're doing is because we're working with pieces of matter that are just nanometres across, the nanometer is the length scale associated with a lot of quantum effects. So yes. So in order to do nanotechnology properly you'd need to understand quantum mechanics and physics gets very strange
51:59 - What's the biggest molecule?
What's the biggest molecule?
Ljiljana - If we talk about the synthetic ones, there is the one that was made recently, relatively recently, 2014 in Zürich, and it's called PG5 and it's a polymer generation five. It's a huge branched polymer that has 17 million atoms. So the scientists managed to...
Chris - Of what?
Ljiljana - Of, they have carbon, nitrogen and oxygen in its structure. And if you imagine water has three atoms, this is huge.
Chris - So what is this stuff and what would one do with it?
Ljiljana - So they wanted to make it because there is a kind of ongoing competition, who's going to make the bigger polymer. So and... with using the standard chemistry, so they did a very nice trick where they use all the standard polymer chemistry to make such a giant molecule.
克里斯-但是有什么区别a rubber tyre? Because if I make a huge rubber tyre that's an enormous polymer isn't it? So is that not a massive molecule?
Ljiljana - It's not actually. It is a polymer but it's not as huge as you are actually making it.
Chris - So it's lots of molecules added together, not all linked up?
Ljiljana - This one is really linked chemically, all the atoms are linked chemically. So they're thinking because it has a size of a small virus. So it's a 10 nanometres size…
Chris - What the molecule itself?
Ljiljana - Yes!
Chris - Wow that is big!
Ljiljana - So they think they will be able to use it for drug delivery, because it has different branches that have different affinity to water. These branches will probably collapse and they could kind of create a shield around the drug and then deliver the drug to the cells.
Chris - Is it easy to make? Because one of the frustrations with many of these enormous things is they are really difficult to make. So although they might have great applications they’re such a pain to make, you can't possibly scale them.
Ljiljana - I agree but this is, this was a particularly interesting paper, a particularly interesting molecule because they have used a standard chemistry so it's relatively easy to make it.
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