Can we Create Artificial Gravity?

07 February 2017
Presented by Chris Smith.

Do giraffes get struck by lightning? What's the highest number a person could count to? How do animals have sex underwater? Chris Smith teams up with Tim Revell, Richard Hollingham, Chris Basu and Danielle Green to tackle your science questions, which range from the bottom of the ocean to outer space!

In this episode

Cat and dog

02:57 - Who would win: wolf or jaguar?

Which animal would come out of the ring alive?

Who would win: wolf or jaguar?

Chris Smith put this to zoologist Chris Basu, before first checking with the rest of the team...

Richard - I think wolf. But I think in reality wolves because wolves are in packs. I think they would win.

Chris S - Danny?

Danni - Yeah, I’d go wolf as well. I think they’d go straight for the throat to just get in there.

Chris S - Tim?

Tim -  Well, I was also going to go wolf but I don’t want to be a Shaun the Sheep. So I’m going to say jaguar.

Chris S - Well Chris, put us out of our misery. What’s the answer?

Chris B - Well, I think if I was locked in a zoo enclosure with one of these animals, I definitely hope it was the wolf. First of all there’s the weight issue. A jaguar can weigh up to about 100 kilos and a grey wolf is about half this, and then there’s the you knew army aspect. So wolves tend to hunt in groups so groups of six and over will take down something about 100 kilos. If the jaguar’s by itself it really won’t need any help with taking down a wolf. So I think it’s the cat every time… not contest!

But, on a personal note, I’m also a veterinary surgeon and if I’m faced with an angry cat or an angry dog, I would definitely prefer the angry dog. Cats are way meaner.

Chris S - People say that cat bites are really nasty compared to dog bites because their teeth are much sharper and more penetrating, so they tend to produce deep-seated wounds that you get certain kinds of infections in there like pasteurella, multocida infections and things… nasty.

Chris B - Yeah. Cats bites are absolutely horrible. Cats mouths are really, really dirty things and, yes, they just inject these bacterial deep into your soft tissues. It hurts - it definitely hurts.

Chris S - And we have these things as pets?

Chris B - I love cats.

Chris S - It’s fun isn’t it how people break down into a cat person or a dog person. Do you find that with the patients that you see?

Chris B - I’ve met plenty of people who are quite polarised either side. Yet crazy, crazy cat people, I guess like me and you get crazy dog people as well. But there is a middle ground you’ll be pleased to know.

Chris S - Danni; dog person, cat person?

Danni - I was raised by greyhounds. All my early memories are of this big white greyhound called Mitzi. Even being toilet trained, I’m not going to go into i,t but I don’t remember my parents being there. I’m sure they were but, yeah, definitely a dog person.

Chris S - Tim?

Tim - I think if I have to decide, I’m probably a dog person, but I’m really neither. Having an animal in my house is not the top of my list so if I had to have one it would be monkey... definitely.

Chris S - Although there’s been a lot of  new coverage about people taking captive primates in the wild isn’t there and it’s causing quite a lot of controversy - Chris?

Chris - Yeah. Monkey are not really suited to be pet animals. They’re highly, highly intelligent  and we put them into these domestic situations where they’re just not suited and it’s quite a stressful thing. So I’m quietly judging you for your monkey comments here.

Tim - Can I just say that was a joke and I do not plan to take a primate or anything of the sort from it’s natural habitat and put it in my home.

Chris S - Just call Tim Michael Jackson.

06:03 - What's the highest number you could count to?

If you started counting when you were born, what number would reach before you died?

What's the highest number you could count to?

Chris Smith put this to Timothy Revell...

Tim - To answer Simon’s question, I assume that he would be born today and that means he would be expected to live to about 81 years old and, in seconds, that’s about 2.4 billion second which, honestly, is pretty rubbish. Even if you could count every single second of your life, and you didn’t have to take any breaks for eating, or for sleeping, or for drinking, or anything like that, even if you could count two or three numbers every single second, which you couldn’t. When you got to 100 thousand or 100 million it would take you a few seconds for each number, you still wouldn’t reach a trillion. And I think if you're going to dedicate your life to something you’d want to reach a number that you couldn’t even think of. You want some sort of squillion or quadrillion that people have never heard of, but a trillion you’re not going to reach which I think is pretty rubbish.

Chris - Has anyone tried this? What’s the Guinness Book of World Records say on this?

Tim - the best example I could find was there was a guy called Jeremy Harper who, in 2007, decided to count to 1 million for charity. And he streamed himself 24 hours a day so you could just look in at what he was doing at any given moment and he counted for about 16 hours every single day, and it took him a total of 89 days to finish. So, if you just work that out, for him to get to a billion it would have taken him 143 years, so it’s just not worth your time at all. I mean it really isn’t. Jeremy Harper raised 10,000 dollars throughout his 89 days of counting which, if you work that back, that’s about 7 dollars an hour. So he’s have been better off …

Chris - He’d have been better off getting a job and donating it all to charity.

Time - Yes, absolutely. That’s the worst idea. It’s not good for you in terms of money, it takes a lot of time to count very high, so don’t bother doing it.

What is the longest animal in the sea?

Chris Smith put this question to Danni Green.

Danni - Well, although most people think it’s the blue whale and they can get to about 30 metres. The longest animal in the ocean, and indeed in the world, is actually the humble worm called the bootlace worm or Lineus longissimus, which it’s quite aptly named. It’s the longest recorded animal ever found and it washed up in about the mid 1800s after a big storm at St. Andrews, and it was about 55 metres long...

Chris S - This is just a worm?

Danni - … and about 10cms wide. And the thing about these ribbon worms is they a toxic proboscis that whips out and it has a neurotoxin in it that it uses to get its prey. So I don’t know what a 55 metre worm was preying on, but we don’t know what’s out there and how many more of these massive worms there are. It’s actually found
all round the UK as well these ribbon worms.

Chris B - I was wondering, does it have a nervous system that travels the whole lengths, so a nervous system that’s 55 metres long?

Danni - The smaller ones do yes, so I believe it would have. It’s amazing. Chris B - Wow! I wonder how long it takes for potentials to go from one end… Chris - Nerve impulses? Danni - That’s a good question.

Chris S - Because you’d think the sensory nerve information travels about one metre per second in small nerve fibres, doesn’t it? So it might take up to a minute to get your sensation. But motor information is 100 metres a second so movements might go a little bit faster. But that’s intriguing isn't it? Where do these worms hang out, they sound terrifying?

Danni - You find them all around the UK.

Chris S - Really?

Danni - Yeah. The bootlace worm - if you look it up there’s some really cool YouTube videos of them wriggling around. They awesome.

Chris S - What about land animals though Chris? You’re our Zoology/animal expert - biggest land animals?

Chris B - It would have to be a snake of some kind. So I wonder about the reticulated python

Danni - Was the question animal? Because if it was an organism it could be fungus. You know they those massive like - what are they called again?

Chris S - A mycorrhizal.

Danni - That’s a word a can never say, yeah. Those can be like hundreds and hundreds of metres, can’t they?

Chris S - They are literally hectares. I think they’re the biggest moving organism. It lives in America and it is a giant subserve fungal network which is hectares in size so that’s true. But in terms of land animals - how big is a giraffe in terms of its actual mass and that kind of thing? How much does one of those weight because they
don’t look like they would weigh much but they’re I guess actually quite big?

Chris B - Yeah. They vary from about 800 tons up to 1.2 tons sometimes. In terms of height, really, really tall giraffes are about 5 to 6 metres high. Chris S - Is this true Chris that they have special adaptations so they don’t explode their brain with their blood pressure becoming too high if they put their head down to drink? Is that true?

Chris B -Yeah, it’s a bit of problem. You’ve got to be able to push all this blood up to the head so you’ve got to work against gravity. But when giraffes lower their heads to drink, for example, they’ve got this problem of how do they actually stop their heads from exploding, their eyes popping out of their skulls? We think it’s because they’ve got a network of really find blood vessels that acts like a sponge. So it mops up this excess blood pressure when the head it is down and release it when the head is up.

Chris S - I was having a conversation, because medical people do this kind of thing, the other day about animals throwing up and we were speculating this might be a challenge for a giraffe. But then someone pointed out that they were ruminant animals, aren’t they, so they have a very good mechanism for regurgitating what’s in their stomach and chewing it back over again. So, in fact, they should be able to throw up without a problem.

Chris B - Yeah, it’s crazy. You can see food going down the neck and you can see it going back up as well. It’s really creepy when you watch it.

Chris S - Because someone said to me that you have to be careful with cows because if cows eat rhododendron this is very powerful as a mitogenic agent for them - it makes them throw up. And if you think the cow is the size of an oil drum, and a cow is an oil drum of liquid basically, just throwing up all in one go. And if a big field of cows eat rhododendron you can have a lot of cow vomit everywhere.

Chris B - If you see ruminants throwing up then you know something is seriously, seriously wrong. I’ve never seen a giraffe throw up and I hope I never do.

Astronaut on spacecraft

Is a space walk dangerous?

Chris Smith put Loyiso's question to space expert Richard Hollingham.

Richard - It is difficult and dangerous to walk in space. The first astronauts to walk in space were Alexei Leonov for the Soviet Union and Edward White for the US. Alexei Leonov, at the time, they painted it as this great heroic space walk all went perfectly. Well, he barely got into his spacecraft; he was almost left outside in orbit around the Earth. Ed White had a great time pinging around with this little jet pack thing and this little rocket gun he had and he made it look so easy.

It turned out to be really difficult. Because people imagined it being like swimming. I’ve done the NASA virtual reality training where they train astronauts at Houston. They set me down in this virtual reality headset. They sit you on a chair and they press the button and then suddenly you’re in space. Wow! Right above the Earth. The temptation is, when you leave the International Space Station, you’re looking down, you pull yourself out of the space station on these railings. And then if you let go, you move away and then the temptation is to swim back towards the space station, and you can’t because you’re not pushing against anything. There’s nothing going on, so it becomes very difficult.

During the 60’s they figured this out with lots of handrails, lots of things to grab onto, things to anchor yourself to. And what they found was, they hadn’t thought about this. This is what I found incredible. They’d have a spanner so they’d have to turn a bolt on the spacecraft. Of course, you turn a spanner and you turn as well. So they had to work out we’ve got to anchor ourselves, then we can turn the spanner.

Then you think about the other problems with a spacewalk. You’re in your little spacecraft, essentially; a spacesuit is a spacecraft. You’re connected by an umbilical and you certainly have a backup life support system on you. So there’s all the things that can go wrong with your personal spacecraft. Luca Parmitano, a European astronaut, a couple of years ago now his spacesuit started filling up with water. So he was the only astronaut who almost drowned in space because there was a leak inside his spacesuit.

Chris - don’t those spacesuits cost an exorbitant amount of money - literally millions?

Richard - Yes and they’re all individually made. Some you can adapt to fit different astronauts. But if you look at the size of astronauts and usually the Americans are really quite tall. Tim Peake, the British European Space Agency astronaut is relatively short so they have different space suits. There’s a Russian space suit and the American Space suits - slightly different.

Chris - Tim Peake’s said he’s going back into space.

Richard - He is, yes. We don’t know when yet but he is going back into space, yeah.

14:38 - What percentage of my atoms do I keep?

What percentage of the atoms we are born with, do we die with?

What percentage of my atoms do I keep?

Chris Smith answered this question from Adel, after first asking the team.

Richard - Well, it’s that great philosophical question, isn’t it, that if we regenerate our cells are we still us anymore? It’s a question you could apply to the Flying Scotsman, for example, to bring it round to trains.

The Flying Scotsman locomotive, built in the 30s, rebuilt so many, so many times. Completely rebuilt recently - is it still the same engine as was originally built because so many pieces have been replaced?

Chris - In that great comedy “Fools and Horses,” I remember Trigger saying - he shows Del Boy his broom and says “this is my Great Grandfather's broom.” And Rodney goes “what the real one?” And he says “well it’s had one or two new handles and heads since then but yeah, yeah, it’s the original broom.”

Danni - do you want to speculate how many of your atoms are the ones you were born with?

Danni - Killed a lot of mine off in the first few years at university I think. But I think what you’re saying about the brain accounting for about 5 percent of your weight, and your eyes and all the rest, I’d say about 3 percent.

Chris - So we’ve got a 3 percent from Danni. Tim any thoughts?

Tim - I think it has to be a low percentage. We know quite a few different cells die and then you replace those cells, and this happens at different rates throughout your body. I think this happens for most of your cells, so by the time you’re dead, I’m thinking you’ve replaced quite a few of them.

Chris - I think it’s actually quite a difficult one to know the precise answer to this. But making it into the simplest question possible, you could argue how much does a newborn baby weigh? About seven and a half pounds or in new money, three and half kilo or so. How much does the average adult human weigh? Seventy kilo. Therefore your birth weight as a proportion of your grown adult weight is 3.5 divided by 70 times 100. That means you weigh about 5 percent at birth of what you will as an adult. Therefore, if you’re growing from 5 percent to your full size, only 5 percent of the atoms in your body can, by definition, be the ones you're born with. Therefore, if the answer to this question cannot be more than 5 percent, I would argue. Therefore, it’s got to be less than 5 percent but it’s not zero percent.

Now we know that things like your brain and the nervous system, those cells, and some muscle cells are also there for life. Your heart cells, for instance, last you a lifetime. Therefore, the answer probably is what proportion is the brain of your total body mass? It’s a couple of percent. So it’s probably somewhere between 2 percent and 5 percent of the atoms that you are born with last you a lifetime. Because you’ve got literally cells in your brain that are lasting you a lifetime, and the DNA in those nerve cells because the cells are not dividing, the DNA in those cells is not being replaced. So I’d say the numbers close to about two and a half to three percent. That would be my guess.

Richard - Yes. I like the way you show your workings there.

Chris - You get marks for that.

Richard - Excellent. Very good.

Cat playing

17:50 - Why do cats chase laser pointers?

If cats can't see red light, why do they chase lasers so much?

Why do cats chase laser pointers?

Chris Smith put this question to zoologist Chris Basu.

Chris B - She’s spot on. Cats aren’t great at seeing red colours; they’re actually red/green colorblind. So at the back of our eye (the retina), we have light sensitive pigments that enable us to see colour and cats don’t really have the pigments that enable them to see red, so they can’t distinguish red and green lights.

Chris S - They can still see the light but they cannot tell the difference between a red light and a green light. It’s just a patch of light to them?

Chris B - Exactly. It doesn’t really matter what colour the laser pointer is but what they lack in colour perception they really make up for it in terms of their ability to see things like dim light.

So, at the back of our eye we’ve got different kinds of cells that help us see light. We’ve got the cones which are full of these pigments that help us see colour and then we’ve got rod cells. Rod cells are really good in dim light and they’re really good for picking up darty kinds of movements, and cat’s retinas are jam packed full of rod cells.

If you look at a laser pointer and imagine it from the viewpoint of a cat, cats are really good at seeing this dim light so a laser pointer really shouts and stands out at them. In terms of their evolution, they’re primed to chase and see quick, darty movements so it’s really the perfect stimulus for them.

Chris S - Have they evolved not to be able to see the rich range of colours that we have purely because they are really nocturnal animals? They hunt at night when there’s low light and, under those conditions, you can’t actually see colours anyway.

Chris B - It’s a question that lots of people have asked before. If you imagine the mammalian ancestor - a small potentially nocturnal anima, that’s one idea that mammals as a group have lost the ability to a wide spectrum of colour. And it’s only as you go further down the evolutionary line when you get to animals like primates, although their ancestors may have lost some of these colour-sensitive pigments, primates have regenerated that ability to a certain extent. So primates, like us, see colour and that’s because we’ve regained that ability through time.

Chris S - So a cat wouldn’t be able to tell the difference between a ripe and an unripe strawberry for example?

Chris B - No. Cats would be really terrible at picking fruit. Yes, really, really rubbish at that job.

20:35 - Are keys more secure than passwords?

Why do we still have physical keys when passcodes are so effective?

Are keys more secure than passwords?

Chris Smith put Stella's query to Tim Revell...

Tim - To answer Stella, she doesn’t have to use a set of keys if she doesn’t want to. I have a friend, for example, who has a really cool setup. When he’s on his way home his heating slowly starts to heat up because his phone knows he’s on the tube on his way back home. And then, as he slowly starts to get towards his door, his lights come on automatically because he’s starting to get inside his wifi zone. Then as he gets to his front door, of course he doesn’t have a standard key turning lock, he’s got a number pad that he just types in the number and opens up the door.

This stuff is already here but the reason why a lot of people still have keys is because they’re installed on a lot of doors. How many people do you know that have actually bothered to change the locks on their doors? And these things are still a bit more expensive. A lock is a very simple mechanical device that you turn and a bolt goes through the door.

A lot of office buildings have these sorts of things where you can use a retina scan or you can use a fingerprint so this technology is here. So if Stella really wants it, she can have it.

Richard - What about power cuts or the wifi going down? I have a stereo system round the house which is brilliant. You show off to friends and everything - look what I can do on my phone - I can do all this. And then the wifi goes down and then it’s rubbish.

Tim - This is a problem but it depends to what extent. So, if this is actually for the lock on your door probably that doesn’t consume that much power anyway and you would expect it to have a battery that can backup the system should you need to still get in. Quite often these systems also have a lock that you can use with a key as a backup if you need it. A bit like car keys - a lot of car keys are beepers but there’s normally a way to get into the side of the car (a keycard or something) and there’s a little key that you can use somewhere. Yes, we need electricity for this stuff, but it’s not normally much so it’s not too bad if the system goes down.

Richard - It’s not zombie apocalypse-proof?

Tim - No… but neither are regular locks! The thing with all of these things is doors and locks are reasonably secure, but if someone wants to get in your house they’re probably going to break a window. There’s no fingerprint sensor on those so most people don't bother. And a lock is often made of steel and your door is probably made of wood. So you can just saw straight through past that.

Cheeky dolphin

23:14 - How do animals have sex underwater?

How do critters procreate under the waves?

How do animals have sex underwater?

Chris Smith put Eleanor's question to marine biologist Danni Green.

Danni - Well, there’s a huge variety of ways that they do this and I’ll tell you a couple of my favourites…

Barnacles, for example, because they’re stuck on a rock - they’re hermaphrodites as well but they’re not going to be able to guarantee they’ll be able to reach a partner to have sex. So they’ve overcome this by having an extremely long and extendable penis. Barnacles actually have the longest penis to body size ratio of any animal in the world.

Chris - How long are we talking?

Danni - I’m talking about 40 times the body length of the barnacle the penis can extend.

Chris - That’s quite long.

Danni - Yeah. You sort of wiggle that over and bob's your uncle, and your aunt because they're hermaphrodites.

Chris - Actually that’s true isn’t it?

Danni - Yeah. And it depends, the morphology of the penis changes depending on the wave energy too. So if it’s a really exposed, wavy place they’ll have to be a bit thicker, have to have a bit more heff to it. If it’s quite a sheltered shore then they can be long and thin.

Chris - Is that a reflection on the species or subspecies of barnacle or is it that the barnacle is adapting to the environment?

Danni - It’s adapting to the environment, yeah. They can change with the same species but just different wave exposures
.
Chris - Okay, so that’s barnacles.

Danni - That’s barnacles. My favourite one is actually the green spoon worm, bonellia viridis. These things when they’re larvae and they settle on the seafloor they’re sexless; they have no sex assigned. And if they settle in a place that has no other of their conspecifics (the same species) nearby they’ll turn into females. They grow about 15 centimetres long and they’re quite an interesting looking thing.

But if they land near one of the same species, it’ll be a female and it touches them with this pigment called bonella, and that actually turns that larvae into a male. Then what they do is they have this kind of spoon shaped proboscis. They vacuum them up and store the male inside their genital sack. They keep them in their and they’re just little dwarf males and they never get any bigger than a few millimeters.

Chris - So how many males will the female have in her harem then?

Danni - As many as she wants. She’ll just store them in there. There job is just to produce sperm and they become like a pair of testicles, just reduced down. And she feeds them - it’s amazing.

Chris - How does she feed them then? Do they live off things secreted inside the female?

Danni - Exactly, yeah. It’s an amazing system.

Chris - What happens if the female dies? Do the males then perish with her or can they change their sex?

Danni - Yeah. They go down with the sinking ship if she dies. They can’t change after that.

Chris - Once they’ve determined their sex, that’s then locked in for life?

Danni - That’s locked in yeah.

Chris - Imagine that.

Danni - It’s quite cool.

Tim Peake returns from space

Can we create artificial gravity in space?

Chris Smith put this question to Space Boffin Richard Hollingham...

Richard - We know that space is bad for you. Being in space, being in microgravity causes loss of muscle, loss of bone really quickly. You only have to be there a matter of hours before these things start happening.

Chris - Really?

Richard - Yeah. Very, very quickly. Problems with the nervous system, problems with the immune system and we are adapted to gravity, that’s how we evolved. We live around gravity.

Chris - Those nervous system problems and immune problems, are they down to a lack of exposure to gravity?

Richard - They are still being investigated but it would seem certain. There are other things going on in the space environment when you haven't got gravity. You’ve got, for example, with the immune system because you’ve not got gravity, bugs, bacteria, viruses won’t sink so they are around you all the time - there could be things like that. We haven’t got that many astronauts to study at any one time so you’ve not got a great group of people to look at and to study.

Chris - They’ve gone on to live a fairly long time those these astronauts.

Richard - Yeah. They’re doing pretty well. We’ve just had a year long mission but the problem is going to be not so much a year is fine. But a trip to Mars is going to be at least nine months out. Then you are actually on Mars and then you’ve got to come back nine months. You know the ‘giant leap for mankind,’ you don’t want to be coming down the bottom of a ladder and fall off and break you leg or something, which could happen if you’re not adapted, so, at the moment, in space they have various resistance machines. Treadmills for Tim Peake when he was in space he ran the London marathon on the treadmill. So there are adaptations but artificial gravity, that’s the thing we would love. And you look at those fantastic images 2001 Space Odyssey where you’ve got this big rotating spacecraft. The amazing images from the 60s and 70s of these massive space stations that rotate. Because they’re really big, they’re very difficult to make but people are looking at those sorts of options.

Chris - Would it work?

Richard - It would work, absolutely. You could get it to rotate - it’s not artificial gravity it’s centrifugal force. In 2001 that’s a great example. Can everyone remember the 2001 Space Odyssey? Even if you didn’t look through the whole film, it’s a brilliant opening where he’s doing this running. He’s basically running round the inside of the spacecraft. The Martian - the Matt Damon film recently. Again it had artificial gravity with this spacecraft spinning.

Chris - What does it feel like Richard? Do you feel like you’re actually experiencing gravity or do you just feel like you’re on that fairground ride that sort of does the same thing?

Richard - The trouble is no-one knows because we haven’t done it yet. It should feel like real gravity and they are doing some experiments on a much smaller scale. For example, the German space agency actually has a mini centrifuge that they’re looking at putting in the space station.

Chris - Can you put your wife on that?

Richard - No. I put her on a much bigger centrifuge actually. She was really good at it - I was rubbish. I was absolutely rubbish - I really squealed. So it is something that the space industry is seriously looking at. They’ve got to do something so a large spinning spacecraft would be the answer. The problem is launching a large spinning spacecraft. I mean, it’s taking since 1998 to build the International Space Station and you need something a lot bigger. So it’s a huge undertaking.

Chris - So right now you just have to keep up the exercise in space and hope for the best?

Richard - Yeah.

Do any other animals go through the menopause?

Chris Smith put this to veterinary scientist Chris Basu...

Chris B - The menopause, it’s a bit of a conundrum on the surface if you think about it. So, if there’s some kind of benefit to living a long life after the ability to reproduce, how do you actually transfer that benefit on to the next generation? And the and we to that kind of unites the animals that we do know go through the menopause, so people, of course, go through menopause. As far as we know there are only two other species that go through menopause and, surprisingly, it's not an ape, it’s not a primate, the other two are both whales.

Chris S - So elephants don’t.

Chris B - Elephants don’t.

Chris S - They’re very long-live aren’t they?

Chris B - They are and that’s also a question that other people have asked when thinking in the context of why do whales do it, why do people do it, why don’t elephants do it? So the answer to this question is it shows us what we have in common with all these animals and part of it is what’s called ‘the granny effect.’ It’s not called the granny effect after your Nan or anything like that, it’s actually named after a killer whale who was called Granny. Killer whales are one of the species...

Chris S - As you do!

Chris B - Yes, exactly.

Chris S - There’s a story in that - why was it called Granny?

Chris B - Because she was really old, bless her.

Chris S - Okay. It was sort of logical then.

Chris B - People started studying Granny about 40 years ago. She actually died very recently, I think last month, and she was about 100 years old. During the 30 years of research she never had a calf so she was menopausal. But the way that she helped her family group was each year she would take the whales to find out where the best stocks of fish were. So she was helping her immediate family to find the best resources of food and because of that, she improved the health and welfare of her family. So, of course that’s how they get to pass this ability along to the next generation.

Then that goes on to your question: why don’t elephants do this? Well, whales are very family centric and people are very family centric as well. Whereas groups of elephants are not as loyal or rather their groups tend to split off and reform, whereas people and whale family groups tend to stay together very closely.

Chris S - So the fact that the grandma may not be reproducing, but is doing the babysitting and helping with family cohesion means that there’s a strong contribution to the family unit’s success so you breed into evolution.

Chris B - Exactly. She’s passing on the knowledge from her long lifetime. She’s improving the health of the calves, the calves are more likely to survive and then the next generation comes.

Pi

32:46 - How do we keep finding extra digits of pi?

If pi just keeps going, how do we keep finding more numbers?

How do we keep finding extra digits of pi?

Chris Smith put this question to mathmetician Timothy Revell...

Tim - That’s a really good question. So what is pi, let’s start with that? You grab your favourite circle and we call the distance around the outside the circumference. And we call the width, making sure you go through the middle the diameter. If you divide the circumference by the diameter, then you end up with pi, which is just this number 3.14159ish.

But the thing is, I don’t think we take the time to realise just how crazy pi really is. If you take a circle that is the size of a pin prick, or that you take a circle that is the size of the moon and you divide its circumference by its diameter, you get the same number.

This is like some sort of universal conspiracy. This is why mathematicians study this so much. This is why we want to know pi so precisely. Because it’s a conspiracy, how does this happen?

Chris - Why should we be surprised though Tim that that’s the case because a circle, if you make it bigger, then all those things increase in proportion? That’s exactly what pi is so why is that a surprise?

Tim - Well, for me it’s a surprise. Why should there be a particular relation between the way a circle looks round the outside versus going straight through the middle? These seem to me to be rather different things but, obviously, the right answer is they’re not different things because pi is what links them.

Over the years there’s been lots of attempts to try and work our pi to the most number of digits, but the truth is pi is actually a rather tricky beast. You’re never going to work out all the digits of pi because it’s what’s called an irrational number. What this means is that if you write it out after the decimal point you are never going to stop. There are an infinite number of digits after that decimal point.

Over the years there’s been lots of different ways to try and calculate pi beyond just measuring it - various formulas and things, and the current world record is 22 trillion digits which was calculated by a guy called Peter Trueb in 2016, in November.

Chris - Why?

Tim - That’s a good question why? At the moment it just seems to be to show off how good is your algorithm and your computer.

Chris - I was going to say how good is your computer because that’s a lot of memory you’re going to need to handle all of that?

Time - And a lot of time that it takes to actually compute these things. You need a big computer and you need to leave it for a long period of time. In terms of how useful is that? It’s not very useful. NASA, they only use 15 digits of pi, and if you wanted to measure the whole universe down to a precision of a single atom you would only need 40 digits of pi. So to get to 22 trillion is a lot.

Chris - So when we have this question from Hannah which is: how do we keep finding extra digits? Because it’s an irrational number, if you just keep cranking the handle, you will keep churning out numbers as long as you keep turning the handle. It will never end.

Tim - Yeah. We know ways of getting closer and closer to this idea of what is pi? This sort of number but writing down those digits will take an awfully long time so it’s about finding the time and the energy and the people to want to do it.  So we will be able to do that for the rest of humanity.

Could we modify plankton to clean up the ocean?

Chris Smith put Simon's idea to marine biologist Danielle Green...

Danielle - Well it’s a pleasure to hear such a beautiful accent. Zooplankton already do eat microplastics and they pretty much just pass straight through the body.

Chris - And by zooplankton you mean these are little microscopic animals?

Danielle - Little animals - copepods, amphipods, like little crustaceans, little crabs, and they already have been found loads of species to contain microplastics and in the lab they'll eat microplastics.

Chris - What is a microplastic?

Danielle - Technically the definition is it’s less than 5mm in diameter which isn’t actually the definition of microbe - they’re small pieces of plastic. They can either be purpose made - primary microplastics which are microbeads or exfoliants, things like that. They can also be secondary microplastics which are the breakdown of larger bits of plastic litter. Or, actually the most common source is synthetic clothing fibres.

Chris - Why are we worried about them if they’re just plastics bobbing around in the ocean? Why are they a worry?

Danielle - they’re the most abundant form of solid waste in the world at the moment and they’re increasing at a pretty quick rate. We’re not exactly sure how much they’re increasing. But they can go through the food web, and they’ve been found in laboratory conditions to cause harm to certain animals. So they can reduce reproductive rates and there’s a potential for huge knock on effects to the whole ecosystem as well. My own research has found that they can decrease the biomass of microalgae so this is the base of the food web. Because they’re in everything they can have an effect on everything potentially. We’re not exactly sure what they’re doing.

But in terms of the zooplankton and eating them, some other studies have found that they eat them and then poop them out and they become like an accumulation. They sink to the bottom of the sediment and then they become available for other organisms, so deposit eating worms (worms that eat the sediment) like lugworms. Then fish will eat the lugworm, so it’s another way of it becoming available to other organisms.

In terms of genetically modifying, as an Australian in particular, any sort of bio control terrifies me. We’ve had too many bad experiences. But there actually are people working on using bacteria to breakdown microplastics and plastic pollution in general. There was lots of work going on about this but I think it’s potentially dangerous given that a lot of things in the ocean that we use are made of plastic. You don’t want microbes spreading around willy nilly eating the bottom of your boat. You’ve got to be careful.

Chris - No sure. Sounds alarming. The worry, I presume, is that they’re going to be in the water for a really long time whatever the outcome, isn’t it?

Danielle - They’re increasing at a huge rate as well.

Alien Abduction

38:37 - Is it worth hunting for aliens?

Seeing as Earth is just right for life, does that make hunting for ET futile?

Is it worth hunting for aliens?

Chris Smith put William's question to Richard Hollinham.

Richard - Nice question Chris. As Chris said the Goldilocks zone which is the area we inhabit, the Earth inhabits. We are the perfect distance from the Sun, we have gravitational stability so Earth doesn’t wobble around on it’s orbit around the Sun thanks to the Moon sitting there orbiting around the Earth. We have a magnetic field and this is very important for life. The magnetic field gives us this magnetosphere which is like a protective magnetic bubble around the Earth which protects us from charged particles from the Sun, stops us from getting zapped. And we’re pretty much the right size. So everything about Earth is great. That doesn’t necessarily mean…

Chris - Not everything.

Richard - Well no. We haven’t got time to go into all the things that are wrong right now. Let’s talk about all the things that are great physically with the Earth. It’s great for life.

That doesn’t necessarily mean that other places aren’t great for life it’s because life might be different there. I’m firmly of the view there is a lot of life out there. It might not be like us and I don’t think it’s going to be intelligent life. But I think if you look at places like hydrothermal vents deep underwater, and very toxic environments, where you can find particularly bacteria, and viruses, other microorganisms that we thought no way life could be there. You just need some source of energy and probably water but not necessarily.

So the argument with Jupiter’s moons which may have liquid water, energy there won’t come from the Sun, energy there will come from the gravity of Jupiter. So you’re looking at all these places that could have life but it won’t necessarily be us.

Chris - I was very fortunate to go down one of the world’s deepest gold mines in south Africa. And, in fact, in these operations there are microbiologists working because there are seeps of water and you can prove chemically that the water has been cut off from the rest of the world for millions of years, maybe 100 million years plus. You can tell that from the chemistry of the water. And yet when you look in this water which, in some cases is 60 degrees centigrade, you can find it’s thriving with bacterial life. So people said “well where do they come from?”

When scientists unpicked this, and this was a paper in Science about ten years ago, what they find is that there is uranium present in the ore. The radium is spitting out radiation, and the radiation is doing things to water molecules and giving them some energy. The water molecules then attack minerals in the rocks and release them for these microbes to live on, and the first layer of microbes eat those and then other microbes eat those first microbes, and you’ve got this whole ecosystem growing powered by radiation. So once people found that they said well look, it’s not so unlikely that you could have this somewhere else in our solar system, in a very inhospitable place but it’s got a nice warm interior because it’s radioactive and there’s life there.

Richard - Yeah. We can’t answer the fundamental question of how life gets there in the first place, but there does seem to be life in the most unlikely places.

42:19 - Do nurses and doctors get ill more often?

Do our medical professionals get sick more than the rest of us?

Do nurses and doctors get ill more often?

Chris S - A quick strawpoll of what we think here of our panel. Chris, what do you think? Obviously you don’t catch too many things from your patients hopefully because they're animals. But you can catch some things from animals but what about human bugs?

Chris B - I don’t know but i visited my GP the other day. I felt terrible, I had a really horrible sinusitis, I had mucus coming out almost every place. And I went up to my GP and he immediately put out his hand and I’d already told myself I’m not going to shake his hand. But the stupid British politeness in me made me stick my hand out. I shook his hand then he said “how are you feeling?” And I said “terrible. I’ve got mucus coming out of it’s horrible.” And he was like “that’s nice” and then immediately got the hand gel out and disinfected his hands.

I would have thought it would be very easy for healthcare professionals to pick up bugs.

Chris S - And do you know what’s really sad? Is that that hand gel is great for some bugs like bacteria, but there are lots of microbes, including rhinoviruses that cause nasty colds and enter our viruses that cause nasty, fluey colds, they are totally immune to the alcoholic hand gel. So what we end up with a nice pure culture of these bugs on your skin which you then touch your mouth, touch your eyes and they end up in you and you get infected.

Chris B - Yeah. I’m worried about my GP. I might just go and just see how he is.

Chris S - Apologise. A bottle of wine might be good there Chris.

I think the answer is, to answer Cody’s question: yes, people are being exposed more often. We know that people who work in healthcare settings do catch things like the flu more often because we’ve got really data comparing people who have a flu vaccine with people who don’t have the vaccine. And if you look at patients who are exposed to those care workers, the patients have a much better outcome because the catch flu less often. So this shows that there is a trade between what the people come into the hospital with, what the health care professionals then pick up, and what they then pass on to patients so this is actually a two-way street.

The other half of this question is really if I’m being exposed a lot do I develop this sort of superhuman immune system so I’m actually capable of fending of everything? Well the answer is you’ve still got to catch the thing in the first place because your immune system is an immune system because it adapts to what it’s seen before and stops you catching it again. So you’ve still got to catch stuff in the first place, you’ve still got ill at least once for each of these bus in the first place. There are hundreds of different cold and flu viruses out there so you’re going to get ill hundreds of times anyway.

So yes, a) you might develop quite a potent immune response but b) these bugs are very common, they're also mutating and changing the way they look all the time, and the number of exposures is incredibly high. So the likelihood is that medical professionals, and teachers probably too pick a lot more stuff a lot more of the time, and they probably do get infected quite often. And that rally is an occupational hazard isn’t it. Sorry… I think I’m one of them.

Lightning on the sea

45:11 - Do lightning strikes on the ocean kill fish?

Why don't lightning strikes on the ocean kill marine life?

Do lightning strikes on the ocean kill fish?

Chris Smith put John's question to marine biologist Danielle Green...

Danielle - When lightening strikes the sea it spreads out horizontally rather than vertically so it would spread out along the surface. And because most fish and marine organisms tend to live at deeper depths they’re likely to avoid being struck by lightning but it doesn’t mean that they can’t be. There have been cases where people have observed lightning strikes and then seen dead fish floating on the surface. So I think they can be but it’s not something that is a huge problem because it’s not like it’s going to radiate across the whole earth.

Chris S - Because it’s spreading out and, as it spreads, it’s going to weaken quite considerably isn’t it? So the electric field to which the fish is going to be exposed is going to diminish really quite rapidly.

Danielle - Yeah. And in terms of marine mammals as well, there’s been some observations, sort of fisherman’s tales - I’m not exactly sure if it’s true or not - witnessing a whale being struck by lightning and things like that. If a human gets struck by lightning they don’t always die - I think it's 20 percent or something like that. It’s not a good thing. You wouldn’t go out of your way to get it but they’re not always going to die from it anyway. So I think it is something that’s possible but it’s not a huge problem because they’re usually deeper.

Chris S - Tim?

Tim - One of the first things I ever did for the Naked Scientists was piece about a person who’d been struck by lightning and wanted to know about it. The thing I most remember about this is we interviewed someone in the US who was all about lightning safety and he came up with this great phrase that I will remember till the day I die which is “when thunder roars, stay indoors.”

Chris S - Good quote. Farmers, Chris say they sometimes find animals that have died in fields. They sometimes argue that lightning hits the ground or something and then travels across the ground and if you put a long animal like a horse or a cow, it could go up the front legs, along the body killing the animal enroute, and then out the back legs. Do you think that’s true?

Chris B - Yeah. I definitely think it’s possible. Imagine the setting… you’ve got a nice open field with livestock - it seems like a good recipe for lightning strikes. I often wonder are giraffes particularly sensitive to this problem? They tend to hang out in open spaces.

Chris S - But they’ve also got an inbuilt lightning conducter, haven’t they?

Chris B - Exactly.

Chris S - And is that the case because you get some pretty vicious thunderstorms over the areas of Africa where these animals live

Chris B - Again, you hear lots of stories of people saying they’ve witnessed lightning strikes in giraffes. Yeah, I don’t know.

47:40 - Why are the UK and American billions different?

What's the difference between a US and a UK billion?

Why are the UK and American billions different?

Chris Smith put this question to maths-man Tim Revell...

Tim - This is one of those issues that is surprisingly contentious considering how dull it really is. To talk you through what are the differences between the Americal billion and the good old fashioned British billion is when you think about how numbers go up - ten tens in one hundred, a thousand thousands in one million, and then what happens next is where things diverge.

In old fashioned British counting a million million used to be a billion. But in America this would be a trillion, so it’s actually a thousand million is a billion. So it’s true there’s no real logic in the American system but there’s also no real logic in the British one either. Because when you get to what is a British trillion, well it’s not a billion billion, it’s a million billion. So it breaks down in both cases.

But actually, now these two things are the same. In the 70s we decided that we’re going to have the same as the American billion and so, overnight, we had huge inflation and what used to be known as a billion became a trillion.

Richard - I’m totally confused. Is it something of just my age where people over 40 were told that there’s this different system?

Tim - In the UK, these things became standardised in the mid 70s, but the confusion has kept ever since. And I think partly in the UK we don’t really like taking things that are American so people fight against it but yeah, the correct way is a thousand million is a billion and, actually, neither of these things are American or British, we took both of these systems from France.

Chris - So they’ve got two system in operation?

Tim - I think in France they also use the same system that we all use now but they created them both and then, for a while, they used both systems but they distinguished between them by calling them the long scale system and the short scale system.

49:41 - How did we evolve eye colour?

If apes have brown eyes why do we have many different colours?

How did we evolve eye colour?

Chris Smith put this to zoologist Chris Basu...

Chris B - The question of which apes did human beings evolve from? That’s a big, big, big question and that’s the reason why this area of science, the study of human ancestors, is such a big and active area. That’s because the honest answer is we don’t yet know.

We do know little pieces of the puzzle. So we know that by looking at DNA the last common ancestor between human beings and chimpanzees lived about 7 million years ago and when we look at fossils from around this time we do find that these fossils do have things in common with human beings.

So fossils from West Africa are starting to show the really early signs of things like bipedalism. But one of the challenges of this area is, when we look at these fossils, we’re not looking at our direct ancestor. It’s like if I’m studying a photograph of my great uncle and I’m trying to imagine what my great grandfather looked like. So it’s one of these challenges that we’re trying to work out what our ancestors looked like from our distant relatives.

But going to the question of the eye colour yes, our early human ancestors likely had brown eyes. And the diversity in the eye colour that we see today comes from mutation in our genome. So, for example, the mutation that give us blue eyes, we can pin down to about six thousand years ago. And perhaps one of the reasons we do see a lot of variety in eye colour in humans is because of our white sclera. So the whites of our eyes really makes our eyes really stand out, really punch out when you look at them and that’s probably because of things like non-verbal communication, so facial features, are really important in our society. That’s we’re drawn to look at eyes.

How do we get back to earth from the moon?

Chris Smith asked space expert Richard Hollingham to answer Tsheppo's query...

Richard - Well, it’s actually quite an interesting question this. Apollo had two engines so it could go down on the Moon. The last Apollo was in 1972. It could go down onto the Moon, it used the engine to slow itself down and get down onto the surface. Really hairy - if you listen to those communications between mission control and the astronaut you can hear all these things going wrong and then it’s down and it’s fine.

Neil Armstrong, the first lunar landing in 1969, I think it had 11 seconds left of fuel to get down without crashing, but this was an argument for cancelling Apollo. It was meant to run until at least 20 and the last Apollo mission was Apollo 17, so 11 to 17 and 13 didn’t land on the Moon. Was it was a single point failure of getting back. So it was a separate engine to get it off. Those odd looking lunar landers you see, the top part had a separate engine, you press a button and it fires or it doesn’t fire. If it doesn’t fire your astronauts are stuck on the Moon and there is absolutely no way they can get back.

What’s also interesting about this is that the Soviet Union, who never managed to land an astronaut on the Moon or a cosmonaut as they would say, actually had a much better way of doing it. So they had a lander but it would only fit one cosmonaut in. Unfortunately, their rocket was rubbish and the never got anywhere near the Moon but they had their lander. It would have one cosmonaut, get out of the lander and get on the Moon’s surface. If there was a fault with that lander and he couldn’t get back so they had the same engine system, they were actually landing another lander a couple of kilometres away and there was a rover he could use to get to the other lander to get back off the surface.

Chris - Did that land independently with no-one on that one?

Richard - Yeah. So that landed independently with no-one on it. He could use this robotic rover to hitch a lift to get to the other lander and get off the Moon. When we go back to the Moon and when we go to Mars, it’s something to seriously think about. It’s not just getting there. Getting there is relatively straightforward, we know how to do that. It’s getting back and it’s always getting back

Sun shining on waves

53:56 - How much are we damaging the oceans?

How great is the damage humans are causing to the oceans by discharging so many chemicals and excreted drugs into them?

How much are we damaging the oceans?

Chris Smith asked Danni Green, a marine biologist, about John's question...

Danielle - Another Aussie. The Aussies are coming up with all the good questions here. This is something that is a big concern. So basically everything we put down the sink, so disinfectants, things that are in shampoos and soap, also pesticides and different chemicals from runoff can end up in the ocean. And it’s particularly an issue where they build up locally, so in coastal ecosystems and these chemicals can cause issues for organisms.

Some of them can act as endocrine disrupters so they can mess with the endocrine system and affect the way that hormones signal and the production of hormones and this can affect the organism’s growth rates, their ability to reproduce. It can also cause intersex which is when an animal has both male and female characteristics and this can occur in all sort of different animals - invertebrates like gastropods and crustaceans. Also vertebrates - fish and there’s evidence of it in mammals too.

So it is quite a huge problem and we are cracking down on a lot of these chemicals. So the pesticides, there’s strong regulation that has been brought in in 2016 for some of those. As far as detergents and things go, there’s still quite a bit of work to be done there I believe. But yeah, it is a concern.

Chris - Going back to the conversation we were having earlier about how long things like plastic do dwell in the environment though, many of these molecules are very long-lived. So even though we might put the kibosh on using them now, we may actually have a very long time before we see that they’re completely gone?

Danielle - Yeah. And the problem with some of the research as well is that you might not have strong enough evidence because in your laboratory experiment, you’re using high concentration which aren’t currently found in the natural ecosystem. But this should be treated as a risk assessment of what can happen in the future if we allow levels to keep building up. So yeah, the accumulation is a really important thing to remember.

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