Why do we laugh when tickled?

15 April 2014

In this question and answer special, the Naked Scientists get stuck into your queries, like why are planets round? Why do we laugh when tickled? Does wearing glasses make your eyesight worse? And how many trees could offset carbon emissions? Plus, in the news, the app that could help you get over jet lag and the Heartbleed bug which could affect your internet security.

In this episode

03:26 - How can rodents help model addiction?

How can rodents help model addiction?

Hannah - Well yeah, there are a lot of scientists that work on rodents, rats and mice with this kind of lever pressing paradigm or task and you can for example, stimulate a rat to continue pressing a lever or a button if you give them a nice little reward. That might be a nice food treat for example or it might be a drug of addiction, a drug of choice. And for the rats, they particularly like cocaine and also heroin, and even ethanol alcohol. Actually, 20% of rats will compulsively continue to press this lever in a way that will then give then deliver these drugs even if the rats will then receive a very mild electric shock. So, even if there's adverse ramifications of pressing this lever, 20% of rats will want to continually get cocaine or heroin or ethanol, in order to stimulate the reward centre of the brain, the nucleus accumbens. It causes this release of dopamine, this flush of dopamine, this flush of reward and pleasure in the brain of the rats. Chris - I was going to say, why do they find it pleasurable when they put this electrode in this part of the brain? As Peter's saying, why do the rats find that pleasant?

Hannah - Well, it's because we've all evolved to feel pleasure. I mean, it's part of the things that drive us to success and to succeed as a species, we have to feel pleasure and feel reward, and feel motivation for things. And so, drugs of abuse and also, this kind of electric shock kind of thing that you can do will actually stimulate this reward and pleasure pathway. Interestingly, 20% of humans will actually kind of go towards more of this compulsive behaviour and also, kind of go towards adverse ramifications of drug abuse for example and seeking drugs of abuse. And so, that also taps into that system.

Chris - Ramsey.

Ramsey - So, is this helping us to learn about how to treat addiction in humans?

Hannah - Yes, so, this is why scientists are so interested in it. So, they're actually trying to find the genetic basis for why there's this conserved 20% of both rodents and also human populations that seem to be keen on tapping into this kind of reward motivation pathway in the brain. And there's other animals as well in the world that seem to exhibit this kind of interest in reward and pleasure. For example, I was in New Zealand recently and there was these Tui birds, that are these beautiful iridescent magpie type birds and they like drinking or supping on this flax fermented flower juice and that get them quite tipsy and then they soar around in this tipsy way. So yeah, it's not just rats, it's not just humans. It's also other birds and animals.

06:24 - Why do the farts of others smell worse?

Why do the farts of others smell worse?

Hannah - Well, I would say that my farts really are quite stinky even to myself and I asked my boyfriend about this and he agreed. But he said that his own farts, he found curiously pleasant - was his expression.

Chris - Is everyone universally in agreement here in the studio?

Hannah - Not about my farts, about your own.

Helen - I think it's particularly bad if it's someone else's because it's more the thought really that it's not come out of yourself, your own body. And maybe, is it a similar thing to other sorts of bodily fluids like - I don't know - mothers get very used to their children's puke and poo, and all sorts of things because they kind of have to. But if it was another child's puke and poo, I'd presume they wouldn't be quite so pleased of getting close to it.

Hannah - There have been scientific studies on farts and also, baby's poo. In a blind study, mothers find their own children's poo more pleasant smelling than other children's poo and the same can be said of people's farts. So, just imagining the smell of your own farts, people rate it as okay, but if you're asked to imagine the smell of anyone else's fart then yeah, they think it's disgusting and it's possibly...

Chris - I was going to say, one theory I heard of this is that one person pointed out to me that one possibility is that the gases that you're going to release don't just come out of you, out of your rear end. Effectively, those volatile chemicals go into your bloodstream a bit and that means they get carried up to the receptors in your nose via your bloodstream and they desensitise the receptors in your nose a little bit. You effectively get used to the smells you're going to make and this means that because you've been smelling it already, it doesn't smell quite as offensive to you because it's less new to you compared with someone else who's having to put up with it for the first time. Ramsey...

Ramsey - Similarly Chris, I believe that our sense of smell is relative. So, we get used to smells in other words. So, when you come home from holiday and you open your door to your house and you sort of think, "Oh, it smells a bit musty. I'm going to go and open some windows." It might not actually be a musty house at all. That is the smell of your home. You just normally get used to it and I think we all probably know people who we think smell a lot like their dogs, or generally, smell a bit funny in general and you kind of think, how does this person not notice they're a bit smelly. Well, we all get used to our own smells and it's because it's a relative sense that we have.

09:03 - Why are planets round?

Why are planets round?

Tamela - That's a great question. It comes back to this idea that - well, this knowledge that gravity is a central force, it's acting radially inwards and pulling mass, anything with mass towards its centre of mass. So, to go back to the formation of planets, we expect that stars and planets would've condensed and collapsed down from these massive clouds of gas and dust, these nebulas. As they were collapsing, they were attracting other bits of matter and the natural equilibrium state is for everything to be as close to that centre as possible and to be in a sphere. It wants to be equidistant in a sense. Bigger objects have more mass and that strength of gravity is greater. So, it really starts to smooth without the surface. A smaller object might be a cube and material properties of that cube can keep it up without gravity pulling it into a sphere.

Chris - It's a bit like raindrops I suppose isn't it because you've got a droplet of rain coming down. If it can forms a sphere, but then it sort of smears out a bit with the air current pushing it. It's the same sort of phenomenon - the water sticking, pulling itself together.

10:12 - How do our actions affect our genes?

How do our actions affect our genes?

Chris - Well, the answer is, absolutely it does. There's a number of different ways in which this may happen. If you think about it, I don't know if you go to the gym, but if you go training, you know what happens to your muscles?

Catherine - Yeah.

Chris - They get bigger, right?

Catherine - Yes.

Chris - Well, if they're getting bigger, they're growing. If they're growing, they must be producing more of the tissue in a muscle that makes you strong. These are the contractile filaments, actin and myosin. Those are proteins and they get made by turning on a gene that tells our cell how to make them. So, in response to training, in other words, activity, you trigger more genes to get turned on in your muscle cells to make more of the bulk of your muscle. So, there's one really good example of immediately how one of your actions affects your DNA. It affects how active bits of your DNA are. Another example might be for instance in your brain because we know for a fact that when you're subject to certain stresses and strains as you grow up then your brain changes its shape and it puts out connections from one set of cells to another set of cells. Those are controlled by genes and in response to certain long term stresses, we know that certain cells change their behaviour and they upregulate or down regulate. In other words, increase or decrease the production of certain nerve transmitter chemicals. Again, this is a change in response to your activity. And then there's the real kind of far-end of the spectrum which is something we talked about last week on the programme. We talked to Marcus Pembrey who's from Bristol and he did a study looking at fathers who started smoking before the age of 11 and they followed up their children. They found that the sons of those men who started smoking very early were much more likely to become obese in later life compared to individuals who started smoking later and the fathers themselves who were in the study were not obese. So, we couldn't argue it was just something that was a background genetic effect. It seems like there is something changing in the DNA passed on to those offspring from the fathers who smoke in response to their smoking habit. One possibility is a phenomenon called epigenetics. This is where the DNA itself doesn't change, but there are chemical markers added to the outside of the DNA, almost like signposts that can turn genes on or off, or turn the amount that the gene is turned on up or down, and this has an effect. And so, it may be that this smoking habit had the effect on certain genes linked to growth in those children. So, the answer to your question is, absolutely and there are some good examples.

13:22 - How many trees to combat climate change?

How many trees to combat climate change?

Helen - When it comes to climate change, yes, back of the envelope calculations, there's lots of variables when it comes to figuring out how much carbon is stored in the short, medium and long term in forests, with the general idea being that you've got enormous trees, the wood and the carbon inside that is carbon that would be otherwise be in the atmosphere. A kind of very basic idea to bear in mind is that it's thought that about 50% of the dry biomass, the dry weight, if you take the water out of a tree, out of plants, about half of that is carbon. And you can translate a tonne of carbon stored inside a tree to about 3.6 tons of carbon dioxide in the atmosphere roughly and then if you want to do a back of the envelope, I believe that last year, 36 billion tonnes of carbon dioxide were put into the atmosphere just from burning fossil fuels. So, it's a lot of trees. I did find one study which I thought really kind of nailed home just how many trees we would need if we were going to do this and this was based on UK emissions only. This was a few years ago, but I think we can get a good idea from this. Just cars, if we wanted to offset just the emissions from cars in the UK, we would need to plant between 3 and 12 million hectares of woodland, depending on which species because that matters. Currently, there's only 2.5 million hectares of forest in the UK and 23 million hectares of land. If we wanted to offset all our emissions in the UK, we would basically need 2 Britains. We don't have enough space. We would need to plant about 50 million hectares of conifers in plantations to fix that carbon. So, it's a lot of trees.

Chris - That is an awesome number of trees.

Helen - It is.

Chris - I wouldn't have thought it was as big as that.

Helen - It is huge and then there are a lot of trees in the world and a lot of carbon is fixed inside those forests which is another important point, which is apart from just planting new trees, we also have to try and stop cutting down the ones we've got because that also releases a huge amount of carbon dioxide into the atmosphere. And also, trees that grow at the edge of the oceans - mangroves are very important stores of carbon - natural carbon stores. So, we should be thinking about replanting those areas of habitat as well.

Chris - What about your favourite places though Helen, the oceans because don't they account for a disproportionate amount of the CO2 pulldown in the form of marine plants - algae?

Helen - Yes, absolutely. It's about half actually. Half of the productivity if you like, the photosynthesis that grabs carbon dioxide from the atmosphere and makes it into organic molecules. Half of that happens in the ocean. Half of that happens on land in forests and grasslands and so on. So, the oceans are enormously important. And also, carbon dioxide just dissolves in the ocean. If that hadn't happened, and if the oceans weren't there, climate change would already be enormously worse because there just would be much more carbon dioxide already in the atmosphere.

16:45 - An app to help jet lag

Is there a better way to get over jet lag than just waiting 1 day per time zone to recover?

An app to help jet lag
with Danny Forger, University of Michigan

If you've ever travelled across time zones, you know only too well how disabling itA plane wing is when you arrive in that new time zone and you have to think and work or at least enjoy your holiday. But is there a better way to get over jet lag than just waiting 1 day per time zone to recover? Danny Forger who's a computational biologist at the University of Michigan spoke to Chris Smith about a new app called Entrain which he says will help.

Chris - How does this work?

Danny - The app that we've just released, we used mathematics to calculate the quickest way to get an individual from one time zone to another. And so, the app puts this research in the hands of individuals.

Chris - First of all, tell us how does the maths mimic what's happening in a real body?

Danny - So, this is something that I've been working on for many years. In fact, I started working on this when I was an undergraduate at Harvard. There were a lot of experiments that were going on, testing human circadian rhythms. So, they would bring humans into a sleep lab and shine light on them and see how light affected their circadian clock. Light is the most important signal to your circadian clock. It's so important that in your eyes, there are actually specialised cells, separate from rods and cones that sense light, and send that information to your circadian clock. So there was a lot of data in particular, what was great about it was that it was human data where they gave individuals different pulses of light and what we did was we put this altogether into a mathematical model that we were able to show, was able to reproduce this data.

Chris - So, you've effectively built the human body clock in a computer.

Danny - Exactly. And how the model works is you give it a schedule and then it will say, "Well, at this particular time, you're not quite over your jet lag" or "At this time, you happen to be in Jakarta but your clock is back in Tokyo." What's significant about the paper that just came out in PLoS Computational Biology is that we were able to enter the reverse problem, rather than saying, "Here's a schedule and let's test it", we are able to say, "Of all possible schedules, which ones will get you from one time zone to the next in the quickest way possible?"

Chris - In other words, were I to depart from Heathrow today and head to Sydney and therefore, flip my body clock by, at the moment, about 9 hours, then what would I have to do when I get to Sydney to get myself feeling right and functioning best in the least possible time?

Danny - So let me start with what people thought you would have to do. We thought that the answer to this problem was going to be extremely complicated. Something along the lines of, at 4:00 o'clock, you would have to get 100 lux of light. At 4:45, you'd have to get 500 lux of light and that's really difficult, if not, impossible to do, except for certain very specialised people like Olympians for example or classical musicians. But the math actually came up with a very simple answer to this. Actually, it showed that that simple answer was better than anything else you could do. Basically, all you want to do is control when each day, you start getting light and when you start getting light, we'd suggest you get as much light as possible during that period and when you should stop getting light. So basically, just by controlling your dusk and dawn, you could get to the new time zone as quick as possible.

Chris - Does it work? That's the key thing.

Danny - Again, we know certain facts. We know that the model represents this human data very well and it's being used a lot and we know mathematically that these schedules are optimal. But again, I do think that we do need some more testing at this. In particular, all the work that's been proposed thus far is all based on laboratory studies. And what could be happening in the real world is quite different. Also, to test one individual schedule could cost hundreds of thousands of American dollars or British pounds and take years. And we have thousands of possible schedules if you think about all the possible permutations you could go through and all the possible light levels. So, that's part of the point of the app. The app is released for free. It gives you the access to the leading research. It actually simulates these models on the iPhone to predict where your circadian clock is and it also pulls out the optimal schedules to give you a suggestion of what to do. After doing this, you had the option of sending back your schedule and also, evaluating it anonymously to the University of Michigan. So, that's how we're going to test it. All I could say though is that this is the best answer we have right now.

21:42 - Does wearing glasses make uncorrected vision poorer?

Does wearing glasses make uncorrected vision poorer?

Hannah - Great question Gerry, and it's one that many people ask. So, quite a lot of eye conditions are diagnosed in the teenage years, so you'll see a lot of teenagers starting to wear glasses in their early adolescence. Then they might find that their presciption changes and that their eyesight is actually decreasing, and they might be thinking "well hang on a second, are the glasses actually making my eyesight worse?"

What seems to be the case, actually, is that their eyes are still developing and the way that they focus light onto the retina at the back of the eye, which helps to make sure that they can see things in a clear way, so it's not blurry for either short sightedness or long sightedness. That lense is still developing and still changing in the eye all the way through to about the mid-twenties along with the rest of the brain. So the teenagers aren't seeing that the glasses are actually changing their prescription, it's that their eyes are actually changing and therefore that's why their prescription might be worse. What Gerry's talking about is probably that he's got a condition called Presbyopia and that's where the lens gets slightly stiffer, possibly age related, so it becomes stiffer with age. So Gerry, your eyesight might be deteriorating slightly with age and there's things that you can do that might help that and that's eye exercises. That's something that I actually do, every day I try to do it. For example, I'll have an imaginary clock in my head and I'll take it in turns, one eye at a time. But I'll make my eyes go through the clock so from 12 o'clock, 1 o'clock, 2 o'clock, all the way round the dial and back again. And then I'll start exercising my eye muscles by looking at things that are close to me and then far away, to keep that muscle working. I hope that answers your question, Gerry.

Chris - It's a very good question because a lot of people say, "I started wearing glasses and then my eyesight got a lot worse." I'm wearing glasses. Ramsey is wearing glasses. Is that your experience?

Ramsey - Yeah.I think part of it might be again, this kind of relative behaviour that we have that your eyes start getting used to the fact that they don't have to work as hard when you've got lenses on. But I suppose it's very hard to tell because if you're going through the process of losing your eyesight then after a year and you take your glasses off, you go "My eyesight is even worse than it was a year ago."

Chris - Yeah, because that was going to be my point that when I was growing up, obviously, along with many people, I started wearing glasses in my teenage years. Was that your experience, Helen as well?

Helen - Yes, I was doing my A levels. I remember I couldn't read the clock when I was looking up from doing work. I think that was another thing is, reading and looking at close screens. Does that make your eyesight worse? And I've been told no, if it's going to get bad, it's going to get bad, and maybe get you get bad quicker, but it would've happened anyway.

Chris - Exactly. If at that time in your life, the same processes of development which are making you become short-sighted for example, are still going on, when you put the glasses on, obviously, you see better. But then the process is still continuing along underneath that, so your vision continues to deteriorate and then you think, "Oh! I got these glasses. It was alright, but now look, it seems to be getting worse." Actually, it's the same deterioration you were going to get. Once people get a little bit older then their vision settles down and they stop getting the deterioration. My lens prescription changed when I was teenager but then it stopped changing and it's been the same for many years ever since. Tamela...

Tamela - Well, I have a question for you maybe. So, I have been very short-sighted since I was about 11. I had to get glasses and I thought maybe it was because I was reading a lot as a child, but I have two younger sisters and they both about the same age needed glasses and my mother as well. I was wondering if it's genetic. Do we know this?

Chris - There is an element of that. People have found this runs in families, but the really interesting thing is, if you look at populations in Singapore and you look at individuals in China, the Chinese now are putting on their desks at school, bars so the kids can't get their heads close to their work because we know there's an association between a lot of close work and not developing distance vision in young kids. Singapore has a really big problem with their military. They were struggling to recruit people who had good vision. So, it might be there is a genetic effect and that genetic effect manifests when you give it the chance to. In other words, if you are genetically predisposed to get short sight and then you do a lot of close work, and you don't force your eyes to develop a longer capacity, you might then become short-sighted. So, I don't think it's as simple as saying, "My dad is short-sighted. Therefore, I will be." It might be sort of loading the dice a little tiny bit.

26:36 - Why are number plates reversed in my rear-view mirror?

Why are number plates reversed in my rear-view mirror?

Ramsey - It's a great and potentially tricky question. So certainly, everything is the wrong way around. So, trees and buildings have fantastic symmetry so it's hard to glance at tree and determine if you're seeing it the right way around or its reflection. Text we're obviously extremely good at looking at and recognising instantly if it's the wrong way around or not.

The big reason is basically, the difference between a reflection and rotational symmetry. So, if I stood in front of my identical twin brother, who doesn't exist, but for the purpose of this he does, if I stood in front of an identical twin brother of me and I held out my right hand to shake my right hand, he would go through the same motion, hold out his right hand. Our arms would cross in front of us and we would shake hands. And to all intents and purposes, we'd done the same thing. We both used our right hands, but if I tried to do this with my reflection in a mirror, and I'd put my right hand out, my reflection in the mirror would appear to put out its left hand and we couldn't possibly shake hands. We'd be holding the wrong hands out. That is basically the crux of the difference. When the text that you look at in a mirror is presented back to you, you're sort of looking at the back of it. You're looking at its reflection, not its 180 degree rotation in space which is what you really need in order to read it properly. So, it's the big difference between reflection and a rotation. Mirrors reflect but we need that text to be rotated rather than reflected to read it properly.

28:10 - Why do plants close their leaves at night?

Why do plants close their leaves at night?

Helen - It's a lovely question and the word for it is - Nyctinasty is the word for plants that close their leaves and their petals sometimes at night. And they do it in different ways, it's rather nice. I don't know if you've ever seen Clover? If you went out and looked at some clover at night you would see that they've raised their little leaflets up and pressed them together and other plants fold them downwards. We already talked today a bit about light and how it affects organisms and these plants also respond to light. They have a circadian rhythm, a body rhythm, an internal clock if you like. And this does seem to have an effect on how they hold themselves and the kind of, the nuts and bolts of how it happens is a little thing - a joint-like organ at the base of the leaves. That's called the pulvini. They're basically little blobs of cells and these can change shape based on the pumping of ions. So, potassium and chloride ions get pumped in and out of different parts of these little organs. And then because of osmosis, water then shunts backwards and forwards and either pops these leaves up or squashes them back down again. And then that movement of those ions is affected by blue light in the daytime and by red light which happens at more kind of dusk time and into the night. We think it happens probably to protect themselves from getting cold and in other cases, there are plants - have you ever come across this fantastic thing in the tropics called sensitive shy grass. If you touch it, it collapses instantly. It's the same organ that's doing this, the pulvini is the same sort of reason it's happening but they respond to touch rather than to light and they're really fun. So, if you ever find them, you flick them and they just all collapse down and they think that so they don't get eaten by herbivores that come along.

29:54 - Were fossils from Mars found on Earth?

Were fossils from Mars found on Earth?

Tamela - Yes. I think people can be forgiven for being a bit inconclusive about this because it's just disappeared. So, Derek has got a nice background to this story. So basically in 1996, there is this paper that was published by a NASA scientist and he had found these sort of nanometre scale, chain-like structures on top of this meteorite maybe slightly embedded as well and interpreted it as fossils of bacteria. One of the first criticisms, well, these are a much smaller scale than any kind of bacteria that we see here on Earth. So, how can they possibly exist on these nanoscale things and maybe that's got around by the fact that Mars has a very different sort of chemistry or something exotic like that. It created a lot of excitement particularly because they thought that this meteorite formed on Mars during the period when water existed on Mars. We have a lot of evidence to suggest that this is true, that there were liquid oceans or rivers or something on Mars at some point, but ages ago, 4 billion years ago or so. This is particularly interesting because it was with water and now, it's here, maybe some evidence of fossils. Maybe we found life and I think even Bill Clinton at this time eluded to it and was a huge discovery. Today, there's no consensus that this is actually definitive evidence of life and unfortunately, we don't have that evidence of any kind of life outside of planet Earth past or present. I think one of the main arguments against it was, there's these magnetite crystals that have formed and at the time, we only knew of these being formed by biological processes from little microorganisms that deposit these minerals. But in the early 2000, they were able to replicate these crystals in a lab study without any kind of organic input. As soon as you can do that, people are inconclusive. So sadly, we're withholding judgment until further data comes along.

33:00 - Britain's first cloned dog

This week, a British pet dog has been cloned in Korea. But can a clone ever be man's best friend?

Britain's first cloned dog

dogHannah -   So, this week, it has been announced that a sausage dog has been cloned.  Thanks to a company called Sooam Biotech in Seoul.  So, there was a competition earlier in the year and Rebecca Smith who's a caterer based in West London won the competition.  And so, she sent off some samples from her 12-year-old sausage dog, some skin cells from the pet and sent them over to Korea where they got a donor egg from another dog.  They took the DNA, the nucleus, out of this donor egg and then they added the DNA from Rebecca's 12-year-old sausage dog's ear skin cell, applied a mild electric shock, and then inserted this egg with the new DNA from the sausage dog into a surrogate mother.  And then the clone was produced.  It was announced this week.

Chris -   What was the price tag?

Hannah -   So apparently, they're going to be trying to sell these cloned dogs for up to 60,000 British pounds to UK dog lovers and in fact, apparently, there's 500 dog owners from around the world that are lined up to pay this type of money in order to try and recreate a clone of their beloved pet.  Helen, you're shaking your head at wonder at this story.

Helen -   I get that we have pets and we love them and wouldn't it be nice for them not to pass away.  But this isn't the same.  Come on people, this is crazy.

Hannah -   We're talking earlier...

Chris -   Did they ask the lady why she paid 60,000 pounds for a clone of her pet?

Hannah -   Rebecca didn't pay 60,000 pounds.  She won a competition, so she got it for free.  But I think it was kind of an advertisement to try and get more people to pay.

Chris -   Have they asked in making a report - other people to see they must think there's a market for it.  So, who's willing to part with that kind of money for a clone?

Hannah -   People do, especially the British population, we're known for loving our pets, but there's a big difference here between a cat or a dog that you love has a particular personality,  many people will argue. And you get very attached to that particular pet, but a clone isn't going to have the same personality generally speaking.  You know, genetically, it might be the same, or almost the same. But the environment can affect the dog and also, the dog, the puppy is going to be in quarantine in Korea for the first 6 months because of UK legislation before it's brought into the UK.  So therefore, the first 6 months is going to be in Korea and it's probably not going to have the same upbringing as the puppy that you adore.

Chris -   Clone you may get identical behaving in dog you may not get.

Hannah -   Yeah.

35:36 - Could you grow better gut flora?

Could you grow better gut flora?

Chris - Kevin, it's very interesting you raised this because we're just at the stage now where we can begin to answer these sorts of questions which are really important, but it dawned on people about 10 years ago that when we look at the human genome, we're ignoring at our peril something which is orders of magnitude more complicated which our metagenome. In other words, the genetic contribution made to our health and well-being by the millions and millions of bacteria that live on us and in us. They're all lending us their genetic know-how and they contribute to our health, every bit as much as our own DNA does. When we take antimicrobial agents like the antibiotics you took for Streptococcal throat infection, then this does wipe out many populations of those microbes that naturally live in your intestines and it upsets the balance. What the consequences of that are, varies from person to person. What the long term consequences are, at this stage, we don't really know. But now, scientists are in a position to answer those sorts of questions because we have very powerful DNA technology today that we didn't have 10, 20 years ago. It's now perfectly possible to take samples from individuals, before, during and after antibiotic therapy which is what scientists have now been doing to read the genetic sequences in there and work out what the genetic fingerprint of the microorganisms that live in someone's intestines and on their skin are. And then to see what impact taking antibiotics has on those microbial populations. The evidence is that it makes a very big difference and there's some evidence that it makes an indefinite difference. In other words, once you've taken antimicrobial agents, then some bacteria disappear for good from your intestines and that may have a health consequence. For instance, there are microbes that get lost which breakdown a chemical called oxalic acid. Oxalic acid contributes to kidney stones and it's interesting that people tend to get kidney stones once they reach middle age. And by middle age, they've also had a certain number of doses of antibiotic drugs which makes them much more likely therefore to have wiped out that particular population of bugs. So, it might be that in the future, what we do is either build better antibiotics that are kinder to our native intestinal bugs and leave them alone while treating bad bugs or it sounds rather unpleasant, but what we may end up doing is basically banking samples of what lives inside us. And then periodically feeding them back to ourselves to keep our gut microflora in tiptop condition because we know that that's really critical to be healthy

38:42 - Is it free to charge mobiles while driving?

Is it free to charge mobiles while driving?

Well, for a start, it depends if he's paying for the petrol because basically, that's what it boils down to. So, when you're driving along, any electrical item you run inside your car, is running off the alternator or the battery, and the battery is recharged using your petrol when you're driving, the alternator uses the petrol when you're driving. So, when you plug stuff in, there is more drag in a nutshell and your fuel consumption is affected accordingly. However, a mobile phone costs about 50 p to charge over the entire course of the year, so I really wouldn't worry about it. If he wants to save on his electricity costs, he should probably look at things in his home like his plasma TV perhaps which might be 100 pounds over the course of the year, maybe something like a washer/dryer. The dryer part of a washer/dryer is going to cost many dozens of pounds a year and stuff like that. I think my favourite one is a microwave oven. So, the clock on a microwave oven uses more electricity over the course of his lifetime than cooking food does. So, if you want your microwave oven to cost the least amount of money, don't use it as a clock. Just turn it on when you want to use it.

40:04 - How do we measure the distance to galaxies?

How do we measure the distance to galaxies?

So, it's a huge question. Measuring distances in astronomy is no small feat and there are huge fields of it dedicated to this. Standard candles is a great method actually for galaxies and this allows us to tie into our measurements of a red shift and to verify exactly what distance that is. So, the way this works is, we have a class of objects, say, a supernova or a type of star. We think we understand the physics of it so well that it has a certain intrinsic luminosity, a certain intrinsic brightness to it when it's there by itself. If we then scale that to a distance away from us, it's going to look dimmer. But because we feel like we understand the physics of it, we can then adjust for that distance. So, those are our standard candles and if we can find one in a faraway galaxy, we can scale it to where we think it should be. The red shift is an interesting thing because this is looking at the spectrum of an astronomical object and a lot of times, we are looking for lines in the spectrum, emission from molecular hydrogen or something like that. If this is shifted away from the frequency that we expect it to be emitting at. This can be either blue shifted if it's moving towards us or red shifted if moving away. Then we know if it's moving towards us or away from us. Coupled with this is the expansion of the universe and it becomes tricky when you have local movements of galaxies moving towards us or away from us because that does happen on a local scale. And then on a much grander scale, you have this expansion, the whole universe, the space between galaxies stretching apart. And as you say, you do need some sort of backup standard candle. Large scales, we normally neglect these local random motions and we say everything is moving away and we can quite easily scale a red shift with a distance. Local scales, it's a bit more tricky, good question.

42:50 - Heartbleed bug

A bug called heartbleed in the software behind most of the internet may have been leaking data out to the world.

Heartbleed bug

Ramsey, tell us about this heartbleed computer bug that was picked up and Heartbleed Bugannounced in a big way, big splash this week.

Ramsey - Yeah, it's really serious. There's this protocol on the internet called SSL which stands for Secure Socket Layer and this is a set of tools and rules for computers to talk to service and exchange information in an encrypted way. So, whenever you log in to something like Facebook or Gmail, or use your bank and use a username and a password, your computer and the service setup a secure link to exchange data in an encrypted way so no one can sniff and steal your data. Now, the problem is that a lot of websites using open SSL which is an open source version. In other words, it's free but it's maintained by people who basically maintain it for fun to provide this technology for free. There's a big question mark as to why very big, very rich organisations, using a free version of this very important tool because a few minutes before midnight new years eve 2 years ago, someone checked in some codes to the code base which had a bug in it, a very serious bug which meant that - the reason it's called heartbleed is because you can have a heart beat which is like pinging the server. You can say, "Hello. Are you still there? I want to talk to you." You send a little packet of data and the server responds with the same packet. Now, the bug that was checked in by mistake was that the open SSL software did not do a proper check on this message. If you sent a slightly illegal version of the message, it didn't check it properly, and what happened was the server responded, not only with a little, "Hello. Yes, I can hear you" but it also provided you with 64kb of some chunk of the memory of the server.

Chris - Ouch! So potentially, if someone knew how to manipulate that, they could extract bits of the memory that contained sensitive data, enabling them to then compromise that supposedly secure connection.

Ramsey - Yes, so in a very rapid nutshell, in the server's memory at that time, if you were logged in, if you're using the server yourself, then potentially, your username, your password, the secret keys that are part of your encryption would all be getting leaked to this other person. There was no limit on how many times you could send this malformed message. So potentially, over the last 2 years, malicious people who knew about this could have been regularly copying out the memories of these servers and getting hold of usernames, passwords, secret keys and the certificates which authenticate websites. So in other words, they could start then setting up fake versions of websites and you would log on to them thinking they were real and you'll browser, and all the security systems would go, yeah, the certificate is correct. This is the right version of Facebook, but it's not. Now, the big problem is, this has been going on for 2 years and the big question is, how much damage there is. And so, people should look at all of the things they use like Gmail, Facebook and so on. They should check when the dates of those service is being applied and they should then change their password.

45:37 - What are the future implications of the confirmation of gravity waves?

What are the future implications of the confirmation of gravity waves?

Tamela - Yeah. So, you're eluding to the BICEP2 result which is a telescope down the South Pole run by the Harvard Smithsonian Centre and they announced, as you say, these primordial gravitational waves had been detected in the cosmic microwave background. This is a signal that we theoretically expected to find and people were looking for it and sure enough, there it was. The biggest result of that is really that our theory of inflation, this idea that the universe expanded massively very soon after the Big Bang it's a strong confirmation of that theory. It's very difficult to imagine a very, different theory that allows the same sorts of gravitational waves and the patterns that we see in the background. So, that's a big thing for cosmologists and definitely gives us a bit more information to play with about the beginning of the universe.

In terms of the future for other gravitational wave detections, obviously, this sort of thing wants to be followed up by other experiments and peer review. A lot of people are still really keen for a direct measurement. What they just did was looking out back to the furthest reaches of the universe and back in time. we would love to see a ripple in space-time because of some very massive event that happened coming through Earth and we'd love to see that detected and we've got a couple of experiments. LIGO is the big one. It's from the US and it's this interferometer that's based on the ground. It's got this laser shining between very long arms distances and it's waiting for a gravitational wave to pass through it and it'll just distort that light a bit and delay it slightly. You can imagine this is a really sensitive detector. It requires a lot of fine-tuning in subtracting background noise. So, that's something they haven't yet discovered anything with, but they're advancing it next year. They're releasing advanced LIGO. LISA is a space-based version of that and that may also launch in some form or another in a few decades, so a lot coming on-board.

48:02 - Why do we laugh when tickled?

Why do we laugh when tickled?

Hannah - Tickling is a very, very serious topic, Chris. Scientists take it incredibly seriously. Recently actually, scientists studied 30 volunteers in an MRI scanner to try and get to the bottom of this tickling phenomena of why we find it so hilarious and so entertaining. It's something to do with us, not expecting it, something we're not predicting it is going to happen and we're not sure exactly how it's going to feel or how a person is going to be tickling us. So, people were scanned in an MRI scanner whilst they were being tickled or they were being told a joke and it turns out that both the rolandic operculum, an area of the brain that's involved in facial movements and emotional reactions lights up to both tickling and telling a joke. But then there's an extra area of the brain that lights up when people's feet are being tickled when their feet are poking out of the scanner and that's the hypothalamus which is interesting. Now, the hypothalamus is involved in regulating our feelings of hunger, tiredness and body temperature, and it's also involved in the flight or fight response. So, if you're scared, you might want to fight with someone or run away. And now, producer for the show Kate Lamble, if I threatened to tickle her and apparently, if her boyfriend does tickle her, she will literally thump the person that's tickling her. So that, she seems to definitely have her fight or flight reaction activated by tickling. So yeah, tickling seems to invoke these feelings in people and we're trying to understand. Scientists are trying to understand a little bit more about what happens in tickling. It seems to be an innate response laughing to tickling. So, new born babies, if they're tickled by a parent with a very straight face on, they will still start giggling and laughing away. So, it's something that we have evolved to do and we're still trying to understand it exactly.

49:51 - What does scratching my dog's tummy do?

What does scratching my dog's tummy do?

Helen - Well, I think you might have gathered from me earlier in the programme, I'm actually a cat person. So, I really don't know. Chris - Do cats do that because you know what he's getting at? When you rub a dog's tummy, his legs starts to go.

Helen - I think that you can get that point. There was a point in a cat where you can get that back leg thing where it looks a bit like a rabbit

Chris - What is that all about?

Helen - I don't know actually. I really don't know. Sorry, Chris.

Chris - Does anyone else knows what this is all about?

Ramsey - I would just assume you were hitting a nerve like bashing your knee and making your foot kick out.

Chris - One theory is that this sort of reaction, if you look at where your tickly bits are, they're also your most vulnerable bits. And so, some people have argued that it's a way of drawing your attention to where your vulnerable bits are so that when you're fighting, you can defend yourself because you learn these various manoeuvres to avoid getting those bits exposed. So, if you make it fun because when you're tickling someone and sort of going for the vulnerable bits, you learn to not make those bits accessible so that when you do need to do something that isn't play fighting, you know how to best defend those bits. It seems plausible, doesn't it?

Ramsey - Yes, it is. Especially lots of litters of cats and dogs play fight all the way through their little years and stuff and so, it certainly seems plausible.

51:02 - Does a teaspoon keep champagne fizzy?

Does a teaspoon keep champagne fizzy?

Chris - We're almost out of time but we've got this one here from Kitty. We can have a sort of show of hands on this - does putting a teaspoon in the top of a bottle of champagne stop it going flat? Who believes that one?

Helen - I've never come across that actually. That's the first time I've heard that.

Chris - People say it stops it going flat, but it's not true. It's a myth I'm afraid, Kitty. It doesn't work.

Ramsey - Yes, the air is still exposed in the champagne.

Chris:: Yeah. I mean basically, the gas under pressure dissolved can bubble out and escape and the teaspoon does not make any difference.

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