Do My Eyes have Anti-Shake Vision?
What would we see at the edge of the universe? Are there long term health effects of eating spicy food? Why doesn't diesel need a spark to ignite? It's another Naked Scientists science question and answer show, where we take on your questions! Find out how a volcano makes Mars wobbly, why birds' lungs are more efficient than mammalian lungs and how a single speaker can make so many sounds at once. Plus, an outbreak of a new and lethal strain of E. coli and why increasing ocean acidification may be deafening fish.
In this episode
01:36 - A New and Fatal E.Coli Outbreak
A New and Fatal E.Coli Outbreak
Dave - Making very big headlines at the moment is an outbreak of a new strain of E. coli in northern Germany; it's thought to have stemmed from contaminated salad vegetables, including cucumbers. The infection is a more pathogenic form of the bacteria, causing haemolytic-uraemic syndrome (HUS), which damages the kidneys and nervous system and can be fatal. So far, about 2000 people in Europe have been infected, with at least 17 deaths. Chris- this is your field - could you tell us a bit more about what's happening?
Chris - Well first of all, we've probably never seen this form of E. coli before so it's almost certainly new. It's designated E. coli 0104 and this is just a system of numbers and letters that's used to refer to the biochemical markers which are on the surface of the bug, which is a convenient way of labelling it for want of a better term. It first cropped up in Germany late last month when it was linked to an outbreak of a form of gastroenteritis that was particularly characterised by people losing blood with the motions. So that first of all rang alarm bells and then when the numbers really began to climb, public health officials got involved and began to trace where this may have stemmed from and also, what the causative organism was and it turned out to be this form of E. coli. There's E. coli in the guts of pretty much everything on Earth, but some forms of E. coli tool themselves up genetically and they have this arsenal of molecular weapons that they can throw at us, and this particular strain appears to have some additional genes that enable it to produce a toxin that damages the kidneys, and can lead to blood cells breaking down and that's the haemolytic-uraemic syndrome bit of it. So, it's an unusual form of E. coli where it came from though it's still not entirely known.
Dominic - You said this was an entirely new strain of E.coli. How could a new strain come about?
Chris - Well, the really clear answer to that comes from the secrets which lurk in its genome because you can unpick, in a sort of detective way, the origins of things by asking genetically who are your relatives? And so, what scientists have done is to send samples of this particular organism over to the Beijing Genomics Institute (BGI) which is one of the biggest genomics sequencing facilities in the world. They have picked their way through all 5.2 million genetic letters that make up this bug, and they've began to look at what the genetic sequence is and who - in terms of microbiologically who, this organism is related to. The interesting story that's emerged is about 93% of the genes are direct relatives from a form of E. coli which has been linked to causing diarrheal outbreaks in certain parts of Africa. But 7% of the genome has been linked to a form of E. coli which makes toxins and in particular, toxins called shiga toxins and these toxins are nasty. When the bug initially locks onto the wall of the intestine, it damages the wall of the intestine and then produces this toxin which oozes into the bloodstream. And the toxin has two parts to it - a subunit A and a subunit B - and the subunit A behaves a bit like a molecular grappling hook. It goes around in the bloodstream until it finds this structure which is on the kidney which it can bind to and it locks on, and this then helps the subunit B to crawl inside the cells where it disables the cell's ability to make proteins which are effectively the recipes that cells need to keep them alive. This causes the cells to die. This triggers inflammation. It also causes blood cells to begin to cling to the wall of the blood vessel and break down - that's the hemolysis bit - so you get a combination of kidney damage and blood cells breaking down, the hemolysis. In a small minority of people, this can be sufficiently severe that they unfortunately die which is what we've seen in this time. So it looks like it's a sort of mix and match between a form of the bug from overseas and some other forms of the bug which we know exist in nature.
Dave - It seems a very specific piece of evolution to actually attack our kidneys in this way. Is there any advantage to the bug? Killing its host seems like a really bad idea.
Chris - Well it's not universally fatal as you can see. We think about 2,000 people have been infected with this new strain of E. coli since the outbreak began and interestingly, the outbreak we think now, there's some evidence emerged this evening, researchers are tying this to a festival that happened early in May - 6th, 7th of May in the Port of Hamburg. They think that perhaps the mass gathering of people there, eating some kind of contaminated food stuff - probably salad vegetables, may have spawned the outbreak. The reason that this bug is able to do this is that humans aren't the natural host of these organisms that cause this particular syndrome. In fact, they probably come from farm animals. Farm animals don't have the molecular target for the toxin that we do so they can carry these things perfectly harmlessly to them, and it comes out in their manure. If you use that manure to fertilise your food crops, your salad vegetables, your tomatoes, and whatever to make them grow very well, the bugs that are carried can then get into the food. One of the other things that stemmed from this piece of research being done in Beijing is that apart from being to make the toxins, this particular form of E. coli also has some genes that make it stick better to the cells of the intestine and possibly also to the cells in things like lettuce and tomatoes. In other words, to survive better on those environments. Because salad items aren't really cooked or boiled, usually raw, and as you peel the thing and peel the bug off the surface, then it's probably on the surface even in tiny numbers, and a small dose is an infectious does with this particular organism.
Chris, Dave and Dominic continued their discussion off air...
Dave - So I guess this leaves on to the question which a lot of people have at home is - is there anything you can do to protect yourself? Is it likely to be a major problem?
Chris - Well we're probably seeing two phenomena at the moment. The 2,000 or so people who have manifested it so far may either have been infected at the time the outbreak occurred - that will probably account for the bulk of them, and then there will also be some people who may have caught it from other people who've got it because the incubation period appears to be between 1 and 10 days. So, people who were getting it may have got it and had a short incubation period, having got it off someone who has already got it, or they may just be a slow incubator, having had a smaller infectious dose, for instance, at the source. At the moment, although it's spread to a number of countries in Europe in terms of numbers, all of those numbers appear to be connected to this particular geographical site in Germany. So we think that's the source and we haven't seen onward spread - certainly not in the UK. We haven't seen onward spread across Europe elsewhere, so it looks like it's being contained. But obviously, this means people are going to have to be very vigilant and if people do get these kind of symptoms then they should go and seek help and also make sure that they are very careful with hygiene because it's a small infectious dose and it can spread on surfaces and things like that.
Dominic - So would the bug be just on the surface of the vegetable or would it be spread through the whole flesh?
Chris - I guess what you're asking is, peel it, boil it, or leave it - does this apply here? The answer is that when the vegetables grow, the bugs can get onto the surface of the vegetable, and obviously, if we don't wash them properly then you could pick something up. This is a frequent cause of travellers' diarrhoea when you visit third world countries. People just eat things that haven't been washed properly. But in certain circumstances, if there are small nooks and crannies on the surface of the vegetable, then the bugs can go into those. In certain cases, the plant can then overgrow the bug, almost trapping the bacterium inside the plant's flesh and protecting it like a miniature capsule. So that even if you do peel it, sometimes it's so deep into the flesh, you may not remove at all. So, the answer is, probably, if you are thinking about being safe at the moment, you'd probably be wise to not consume vegetables brought from German markets in Hamburg. As far as we know, there's no risk to people in this country at the moment and as I say, the numbers are not climbing dramatically anymore. So we think it's probably okay.
07:07 - How Sunspots Keep Warm
How Sunspots Keep Warm
A group of Scandinavian researchers led by Göran Scharmer of Stockholm University have uncovered some clues about how sunspots stay warm.
Sunspots appear as dark blotches on the Sun's surface, and they represent spots where the Sun's surface is slightly cooler than elsewhere. Most of the Sun's surface is heated by convection currents which carry heat from the solar core, where nuclear fusion reactions that convert hydrogen into helium provide the energy that keeps the sun shining, up to the photosphere that we see. Sunspots form when the Sun's strong magnetic field is orientated to oppose these convection currents, causing the photosphere to quickly cool down, because there's nothing to replenish the energy that it's radiating away. Typically, it drops from its normal temperature of around 6000°C down to around 3000-4500°C.
' alt='Granules-like structure of surface of sun and sunspots.' >But even at 3000°C, sunspots glow red hot, and without some heat source to replenish the energy that is radiated away, we would expect them to cool further. So why don't they? Writing in the journal Science, Scharmer and his colleagues present evidence that sunspots aren't regions where convection is completely turned off, but rather regions where it's severely weakened, so that some energy from the Sun's depths can still rise through to the surface.
Convection is normally recognised by the characteristic patterns of rising and sinking currents that it creates on the surface of the Sun, called convection cells. You can create a similar effect by looking at the pattern created in a pan of boiling water when you pour peas into it. But sunspots don't show these patterns, which is why they've long been thought to be entirely free of convection.
Scharmer used a different technique, effectively managing to look beneath the Sun's surface by observing it at a very specific wavelength, corresponding to a spectral line of neutral carbon which is only produced by material at temperatures of tens of thousands of °C. The Sun's surface is too cool to produce this spectral line, and so if you see it, it must be coming from deep beneath the surface.
Scharmer not only managed to detect this neutral carbon line at the edge of a sunspot, but also found that it had a blueshift, indicating that it was moving towards us, rising up through the Sun, at a speed of nearly a kilometre per second. That's the first evidence that has ever been found that there is still some weak convection going on beneath the surface of sunspots.
10:47 - Losing Nemo - How Acid Oceans Deafen Fish
Losing Nemo - How Acid Oceans Deafen Fish
with Dr Steve Simpson, Bristol University
Chris - It is a proven fact that if you elevate the amount of CO2, carbon dioxide, in the atmosphere (which we also think is linked to climate change) this will have the effect of acidifying the sea, because carbon dioxide when it dissolves forms carbonic acid. This acidification, it turns out, can change the way that fish react to the world around them. Dr Steve Simpson, who's from Bristol University, has been looking at how this affects their ability to sense the sound of danger...
Steve - My research over the last decade has focused on the behaviour that coral reef fish show when they're looking to seek habitat after a period of a few days of developing out at sea in the plankton. So these are very young coral reef fish, seeking the habitat that they'll spend the rest of their lives on. My interest has been particularly on the importance of auditory cues. So this is sounds produced by animals on the coral reef that the small larvae can detect and move towards and use to pick specific habitats. Recent research that's been coming out over the last couple of years has demonstrated that fish that experience ocean acidification lose their natural sense of smell which is the other cue that fish use to detect reef habitat. So the question that I was interested in testing is whether the sense of hearing is unaffected by ocean acidification and so, would be able to compensate for this loss of sense of smell, or whether hearing is also impacted on by ocean acidification.
Chris - So what was the experimental technique? What did you actually do and what fish did you test?
Steve - We worked with clown fish. Clown fish are similar to Nemo, and are readily available through the aquarium trade. They can be bred in captivity. So for scientists, this is great because it means that we can actually work with the embryos and larval stages of these fish. So we took embryonic clown fish and as soon as they hatched, we put them into different treatments of water that were either based on today's CO2 environment, we bubbled air into their tanks, or based on different predictions, for the CO2 environments later in the century. So we had three treatments where we bubbled in what we're expecting the atmosphere to be like in 2050 and then two different scenarios for 2100 and these are based on scenarios from the IPCC, the Intergovernmental Panel on Climate Change. So we reared our fish through the larval stage in these different CO2 environments and then we took the fish and put them into an auditory choice chamber which was in the lab - so it was a long tube facing towards a speaker and we allowed the fish to move around in this choice chamber while we played sounds to them and we monitored their behaviour.
Chris - What, first of all, would a normal fish or young fish do under those circumstances when played the sounds of a reef in the way you did?
Steve - We were running our experiments in the daytime. We used a recording of daytime coral reef noise and we know from both studies following fish out in the open water or from playback experiments that we've ran in the past, fish naturally move away from this sound. A coral reef is a dangerous place to encounter for the first time during the daytime because of the high density of predators. And so, the noise of all these predators cause fish naturally to move away from the sound.
Chris - And what about when you then substituted fish that had been reared in these enhanced CO2 environments? What did they do?
Steve - So the fish that had experienced high levels or elevated levels of CO2 showed no response to the recordings. So were equally spending time towards the speaker as well as away from them.
Chris - Gosh! So that's quite striking, isn't it? Have you any clue as to why they behave like that? How do you know that these fish haven't gone deaf?
Steve - So it's certainly possible that the fish have gone deaf. There are several potential mechanisms as to what's happened here. It may be that hearing has been lost, although we did look at the growth of their ear bone which is a central part of a fish ear and we found there are differences in the shape or the size of the ear bone between the fish from different treatments. But it's still possible that hearing has been impacted on. If it's not hearing that's been impacted, it may then be neural transmission or the processing of information and the impact could be occurring there, or it may be that the fish can hear these sounds but loses its natural avoidance behaviour. Either way, I mean, any of those three scenarios would be bad news for the fish in the natural environment.
Chris - Indeed, but one area where your experiment doesn't really reflect the natural environment is that you took the embryos from a normal situation and then put them into these enhanced CO2 situations for the remainder of their development until you tested them. So that could in itself be quite stressful, so could it just be the fish are responding in a stress related way and that in fact, if you were to study their progeny, if you reared fish from embryo to adult and bred from them and then took the progeny and tested them, you might see they were less stressed and therefore, less affected in this way.
Steve - Yes, so that's a very important question to ask as to whether it is due to an acute response to CO2 environments or whether the fish through generations have the ability to adapt. That will determine how we think, how we can predict the responses of fish will be over the next century. What we're seeing is an unprecedented rate of change of the pH of the sea, so it's occurring 100 times faster than any time in the last 650,000 years. And so, we're expecting that fish, if they can adapt, will be doing this in a period of only a few tens of generations through that century. And that really is a focus of the lab of my collaborator Professor Phillip Munday who is now working with multiple generations to look at the rate of ability to adapt.
Chris - And what do you think the implications are for what you've found?
Steve - Well the implications are that fish losing their sense of hearing or their natural responses to sound are detrimental certainly to fish, in that fish live in a very auditory world, so this sound to communicate, to detect and avoid predators, to find their own shoal mates, and also to detect potential prey items. So there would be fairly detrimental impacts on fish populations. We don't know whether this impact would be seen across the board in terms of different fish species and that's the focus of our research now, to start to look at the variability of response between species. I think also an interesting question is how variable is the response within a species, because it may be that every fish needs to adapt, or that there are some rare fish that already have more tolerance that would then have that ability through selective sweeps in the population to be able to keep pace with the change.
18:09 - Largest ever DNA computer
Largest ever DNA computer
The overwhelming majority of the computing done today is with transistors in silicon chips, though there are a few other tacks which are being tried. One is using DNA, it can famously encode information, and it is a chemical, so in reactions it can do operations on this data.
In the long run they have been proposed as a way of solving some problems which are very slow to do with a normal computer because although a DNA computer does calculations slowly, DNA molecules are quite small, so it could do a lot of them at the same time, but we haven't quite reached this point yet.
Erik Winfree and Lulu Qian have built a system of DNA molecules that interact with one another, in lots of different reactions. DNA is a double helix, two spiral molecules, relatively weakly bonded to one another. Two DNA molecules can only connect to one another though when they have corresponding codes, and if only half of the code corresponds to one another only half of the molecules will connect, leaving the other half able to make another reaction.
By encoding inputs as the presence or absense of a molecule, a pair of these reactions can give outputs of another molecule, and behave like any conventional logic gates. Computers are made of logic gates so with enough reactions you can build a computer.
So far they have built a system of 130 DNA molecules which can do a calculation... they can find the closest integer to the sqare root of a number up to 16, and the reaction takes about 10 hours.
This, in itself, isn't very useful, but they have built all the infrastructure to be able to make more complicated systems, and read out the results.
The 10 hour calculation time means that it isn't going to be competing with silicon any time soon, but there are places where being able to do simple logic chemically could be useful, for example in a diagnostic test you might want to look for the presence of 3 different pieces of DNA only producing a result if you see them all, or you could only release a reactant only when the first 2 stages of a reaction had completed.
They are also suggesting that life is a complex system of interacting chemical reactions, so we may be able to learn something about it by studying these simple DNA computers.
21:15 - How You Use Your Handset
How You Use Your Handset
with Daniel Wagner, Cambridge University
Chris - Computer scientists at Cambridge University have come up with a way to make mobile phones work more intuitively in the future. With us to explain what they're actually doing is Daniel Wagner. He's one of the team behind the work. Hello, Daniel.
Daniel - Hello.
Chris - He's actually here in person to tell us about it. So, what is the problem first of all that you've been trying to solve? What's the challenge?
Daniel - We've been trying to figure out what people do with their smartphones because if you want to make better phones then you need to know what people do with them now.
Chris - Don't we already know that then?
Daniel - Well this is not really well-known because handset manufactures may be conducting studies, but they don't publish this data. And also, usually these studies are relatively small scale. Mobile operators know what calls you make, but they don't know what happens offline and so for example, which apps you use or when you charge your phone. So what we could do for example, if the phone is charged for short amounts of time, every couple of hours for example, then we could have a battery that charges quickly and maybe for example take a long time to charge fully, but it would still work if we have this kind of pattern present.
Chris - I get it. so, that's the challenge, that's the problem. How have you set out to solve it?
Daniel - Right. So we created an application for Android Smartphones and it's called Device Analyzer. It runs in the background while you use your phone, and it collects statistics of what you do.
Chris - Okay, so what's it monitoring? How is it doing that?
Daniel - It is basically monitoring anything you could think of. So when you charge your phone for example or when you open an application. So we can get some really interesting data from this. So for example, assume that you're in a meeting and your phone rings. So what you do is you're going to turn the phone off, you're going to reject the call and put it to silent, and then from this, we can infer that the phone wasn't supposed to ring in the first place, and this is some data that no one else could possibly get because they either only have your phone records, or they know what you did offline.
Chris - So you collect all these data, it goes into a central database at the university where you mass thousands of call informations from phones together. What are you going to do with this information?
Daniel - So first, before we upload, what's important is that we strip personally identifying information from this so that the people can give us for example a record that a phone call has happened, but we don't necessarily know who was called, so that's important for the people to know. And then we can do aggregate analysis on this dataset and find out patterns that only emerge when you look at a big amount of people.
Chris - And you're going to release this in the public domain are you?
Daniel - Yes this is true. So we give people three months to take a look at all the data that we collect about them and if they're happy with this and give us their consent, then we'll release it into the public domain and give it to other researchers.
Chris - How do people have a go if they want to have a go at the application to participate and help you with the research?
Daniel - The application is available for download on the Android marketplace right now. It works on any android phone and you can just download and it will sit quietly in the background.
Chris - And if you'd like to help Daniel in his research, we've also made it easy for you to get hold of a copy of it. if you go to
thenakedscientists.com/analyser then it will take you to a download option and you can get hold of a copy of that android app and it will then begin to spot what you do on your phone in an anonymous way and help Daniel with his research. Maybe you'll come back and give us an update later on what you find. When do you think you'll have enough numbers to be able to tell us what you're seeing?
Daniel - I think within a couple of months, we shall have plenty of data.
How does a single speaker play many simultaneous frequencies?
Dave - If the speaker was to produce a single frequency, think what that actually means - it means that the speaker is moving backwards and forwards, and causing the air to move backwards and forwards in a sin wave pattern. You've probably seen a sin wave. It's basically just a very specific zigzaggy wiggly line. Now, if the speaker moves in any other pattern than that, you could imagine it's moving slowly with a big wiggle and then on top of that superimposed, there's a little wiggle. So, moving in and out slowly but on top of that is kind of vibrating a little bit. So then it would be outputting sound with the low frequency, the big slow wiggle, and also a much higher frequency as well, at the same time. The way that sound works is you can superimpose the motion of the speaker, you can superimpose lots and lots of different vibrations and that will produce sounds of lots and lots of different frequencies, all at the same time by just making the right pattern for the speaker to move back and forwards. It's not moving in a smooth wiggle, it's doing something incredibly complicated and that's a mixture of lots of different frequencies.
Does Olympus Mons cause Mars to wobble?
Dominic F. - It certainly does make Mars wobble on its axis. Olympus Mons is a massive volcano. It's, I think, three times higher than Mt. Everest. What's important when Mars is rotating on its axis is where Mars' centre of mass is. So that's the average point where all of Mars' little bits of mass average towards. If Mars has a large mass on one side of the planet, then that will knock Mars' centre of mass off the centre of the spherical planet. So it will be rotating around offpoint which is slightly off the centre of the sphere. And that means, as it rotates, the sphere will shift slightly in space.
It's a bit like having two figure skaters on ice and one of them is really massive, it's spherical Mars, and the other one is not very massive and that's the volcano. And as they spin around on the ice, the massive figure skater won't move very much, but you'll see a little wobble each time he goes around.
Now, that's not quite what we're talking about when we normally talk about volcanoes on the Earth, causing a shift in the Earth's axis. What we're talking about there is movements of rock, either because volcanoes erupt or because we have earthquakes, and those movements shift at the centre of the mass of the earth, and that changes the way in which the earth rotates.
Chris - If you would like a good reference on what Dominic was saying, I was very lucky to speak with someone at Harvard a few years ago called Taylor Peron who actually did some interesting modelling on this and showed that when the sea would've been on Mars millions of years ago, this ancient ocean, it produced a shoreline. And if you trace the outline of that shoreline today, you see that in some places, it's maybe a kilometre higher than other bits of the shoreline which suggests either that the water had some very strange tidal movements, which seems unlikely, or more likely, the surface of Mars has been buckled in some way. When they modelled it, they found the buckling was directly explained by the migration of Olympus Mons in exactly the way you say Dominic, pulling the planet surface to put Olympus Mons on the equator of the planet because of that huge aggregation of mass there. So it's Taylor Peron and it was a paper in Nature, I think from 2006 issue if you want to look it up.
29:54 - What properties of diesel fuel make it ignite simply from the piston compression?
What properties of diesel fuel make it ignite simply from the piston compression?
Chris - When you compress air, it gets very, very hot. You're squeezing the air molecules together, you'll get a dramatic rise in temperature, and therefore, you'll need a fuel that in fact can tolerate being put to quite a high temperature before it begins to burn and that's one of the properties of diesel. It's less volatile than petrol. If you put petrol into a diesel engine then the petrol will burn too quickly and it won't run properly which is why you mustn't do that - it will actually damage the engine. But with diesel, what happens is you compress the air in the cylinder and just before the piston gets to the very top of the cylinder, you then open the injector and squirt a mist of fuel in - that's called atomisation. The fuel then burns in this very compressed, very, very hot gas, the oxygen in the air is fuelling that. That then leads to a chemical reaction producing large volumes of carbon dioxide and water and some other partially burned hydrocarbons. This gas takes up a lot more space than the original liquid fuel did, maybe expanding by a factor of 600 to 1,000 and that expansion drives the piston down in the cylinder again and that's the work stroke in which you extract energy from the cylinder by connecting that piston to the crankshaft. So you need a choice of fuel which can tolerate being injected at those very high temperatures and not explode. Petrol will get so hot when you compress it to push it into the cylinder in the first place, it will try and burn in the fuel line and that's what does the damage to the engine.
31:26 - Why didn't light from this distant object pass us when we were closer?
Why didn't light from this distant object pass us when we were closer?
Dominic - That's a really good question actually. Just to recap, the question is, this light was emitted when the universe was made at an age of half billion years and so, the universe could only at that time have measured a billion light years across. And so, the greatest distance this object could've been from us is a billion light years and that light would then take a billion years to reach us and yet, we know the universe is 13.8 billion light years, so why are we seeing this light? What this boils down to is Einstein's theory of special relativity, which I know sometimes makes a lot of people's head hurt and sometimes makes my head hurt too, but I'm going to do my best to explain this. One of the rules of Einstein's theory of special relativity is that moving clocks are said to run slow. So what that means is that if you take a clock and you put it in a fast moving spacecraft for example, that clock will appear to run slow. The laws of physics will appear to run slow so you'll age more slowly. Everything appears to happen in slow motion. Now, we're very used, obviously, to the fact that there's absolute time. So if I sit here and do nothing for 10 seconds then you would all agree whether you're moving in a fast car or whether you're sat still at home that that was 10 seconds. But Einstein's theory says that's not actually the case and that if you're moving in a fast car, then you would appear to see me in slow motion and that 10 seconds will be longer for you.
So what's happening to this galaxy is that because it's on the other side of the universe, it's moving away from us very fast and that means we're seeing it in slow motion. It's evolving in slow motion and so, though the galaxy, in its own reference has only evolved for half billion years. In our frame of reference, that would take about half the current age of the universe to get to that point.
Chris - What about the other half?
Dominic - And then the other half of that time was spent with the light travelling across the universe from the object to us.
Chris - And stretching out in the process because the universe is expanding presumably.
Dominic - That's right and that's the cosmological redshift.
Chris - And that's why we now detect the light that would've been very, very bright high intensity short wavelength light has now got a very long wavelength out in the invisible microwave regime because it's stretched out in that way.
Dominic - That's right and the reason that we talk in terms of the age of the object being half billion years is because obviously, we're interested in how far this object has evolved down its evolutionary track, not when it was in the history of the universe that light happened to be emitted because that's not very interesting.
35:18 - Planet Earth Online - Space Weather Forecasts
Planet Earth Online - Space Weather Forecasts
with Dr Richard Horne, British Antarctic Survey and David Wade, Atrium Insurance
Chris - Although it's a popular conversation topic - it's very tricky to predict the English weather. But what about if you wanted to predict the weather in space? Richard Hollingham is just back from a space insurance conference - I didn't know there were such things - that took place in Italy where 'space weather' forecasting was the hot topic of the day among those responsible for operating satellites and insuring spacecraft...
Richard - I'm walking across a park in the centre of Rome and, well, the weather is lovely. Clear blue sky, slight wispy clouds, a light breeze, but that's only half the story. Richard Horne is here from the British Antarctic Survey. What's going on then beyond the atmosphere - beyond that 'plane we can see in the sky?
Richard H. - Well we're familiar with the terrestrial weather but actually out in space we also have weather, so to speak. We call this space weather. It really is driven by variations on the Sun - we have the material flowing off the Sun which we call the solar wind. It flows towards the Earth and that can disrupt technological systems, modern technology.
Richard - Now, David Wade, you're from Atrium Insurance. Satellites - that's what you're worried about because you insure them. What impact can this stream of charged particles from the Sun have?
David - It can have a number of impacts. One of the most obvious ones to think of would be a loss of power. The Sun pours out some protons, those protons hit the satellite solar arrays and the solar arrays are degraded, but you can also get charging, where different parts of the satellite charge up at different rates and then an arc forms between the two differently charged parts, and when that arc discharges it could cause damage to the satellite.
Richard - What sort of impact would that have on us?
David - Typical impacts could be the loss of communication services, but other aspects such as the GPS system - the navigation system that we've all become so used to these days. We think of it as directing us when we're driving our cars, but it has much wider uses than that; financial transactions, mobile phone towers. All of those are governed by the timing signals that we get from the GPS system.
Richard - So potentially you could lose almost all communications if you knocked out for example GPS?
David - Absolutely. GPS is a constellation of satellites so there are numerous satellites up there, so chances are you may not knock out all of them together. But you could certainly get a degraded service. And that could also be a degraded navigation service; you could see the impact on flights or shipping which may not be able to dock at a particular time.
Richard - Are we talking here, Richard about a hypothetical situation or could this really happen?
Richard H. - No, there are examples where this has really happened in the past. If we go back to 2003, there was a very big magnetic storm at the Earth. Something like 47 satellites were reporting malfunctions. One satellite was a total loss - that was a scientific satellite. It was a Japanese one. It cost 640 million dollars, that's a lot of money. Indeed, over the next few years we are expecting a number of magnetic storms to increase. We know that the Sun has an 11-year solar cycle and we usually measure that by the number of sunspots. But in terms of the magnetic storms, we can also measure that at the Earth, and we measure that by the changes in the Earth's magnetic field. We know that the number of storms is going to increase typically one to two years after the solar maximum, the maximum sunspot number. So over the next three to four years, there's going to be a period of increasing risk, when storms occur and those storms damage satellites and a variety of other infrastructure.
Richard - You say risk - can you see those coming?
Richard H. - At the moment, it's very unreliable. The best we can do really is to take information from a particular spacecraft called ACE (the Advanced Composition Explorer), and it measures the magnetic field flowing off the Sun. We can then combine those measurements with computer models and try and make a forecast of what's going to happen at the Earth.
Richard - That's fine but how far forward can you predict?
Richard H. - By taking measurements of ACE, we've got something like half an hour to one hour's forecast time. Having said that, once the geomagnetic storm starts, what we've established already is that there's something like a four to five-day period that satellites are most at risk and trying to determine how long that period would last and then when it will be safe. That's vitally important to operators, particularly if they want to do orbit manoeuvres or uploading of software and do other kind of operations.
Richard - What would you like to do then?
Richard H.: We're just starting a new project, it's called Spacecast, and we're going to take data from satellites, and we're going to try and generate a forecasting capability. It's an interest for the insurance companies because they want to be reassured that the operators are taking all measures possible to try to reduce the risk of damage and loss.
Chris - Dr Richard Horne from the British Antarctic Survey and David Wade from Atrium Insurance on the impact of space weather on satellites.
Are there any long term adverse effects to eating spicy food?
Chris - Not that we know of. Lots of people across the world eat spicy food for breakfast, lunch and dinner pretty much. That would be my ideal place to live actually! And they don't seem to have any excessive diseases. In fact, on the contrary, there is evidence that Alzheimer's disease is less common in countries where food contains lots of turmeric. Turmeric, being a common ingredient in curry and we know that turmeric contains a molecule called curcumin and curcumin is an antioxidant and it seems to reduce the production in the brain of beta amyloid, the stuff that builds up in the brains of people who develop Alzheimer's disease. So eating curry could actually cut your risk of getting Alzheimer's disease.
Would flashes of light reach Mars?
Dave - Basically, the answer is yes. You would see it flashing. The only way you wouldn't be able to see it flashing is if somehow the light was getting mixed up between when it was on and when it was off and that would mean that the light getting to you would have to be going through different paths and mixing up. Light goes about 300, 000 kilometres every second, so, if it's 2 seconds on, 2 seconds off, then the different paths the light is travelling must be at least 600,000 kilometres different and then lots of different paths and all mixing up, so it mixes up on and off all the time. The reason why you can see stars burning now even though they might have finished burning already is just that the light has been travelling for longer than the life that the star had left when it emitted the light, so it's travelling 60 million years, a billion years whatever, and the stars have now just died, just in the time it took the light to get to us.
Are bird lungs more efficient than mammal lungs?
Chris - I only discovered how different the respiratory system of birds is when I started to actually teach this to the Natural Sciences students at the University of Cambridge a few years ago and it's ingenious what goes on. Birds need a very efficient respiratory system, because they have such high metabolic rates, in order to sustain the enormous work output that they do when they fly.
So how do their chests work? Well they have a very different system to the lungs that we do. We have lungs which are like two pairs of balloons that you blow air into, they inflate and then they recoil down, blowing the air out again. Birds have a one-way flow of air through their lungs. They don't have tiny air sacs called alveoli like we do. They have tiny tubes called air capillaries that the air flows through continuously and the benefit of doing that is that you always have fresh air flowing through the lung, maintaining a very high concentration of oxygen up against the bloodstream and therefore, you maximise the gradient for diffusion, pushing oxygen into the blood.
How do they do this? Well if you were to dissect a bird, what you would see is they have these combinations of lung tissue for want of a better word and air sacs. Now the air sacs are in various parts of the body. They are called anterior and posterior air sacs as two groups. When the bird breathes in, it moves various bones and muscles in order to increase volume of these air sacs anteriorly and posteriorly, so they draw air into them. But, first of all, the air flows into the trachea and it goes into the posterior air sac. The anterior air sacs which also increase in volume, they actually get filled up by the air that's already in the bird's lung. So in other words, they pull air through the lung tissue into their anterior air sac. Then when the bird breathes out, exhales, it squeezes on these air sacs. This time, the posterior air sac empties into the lung tissue and the anterior air sac empties into the bird's trachea and then out through its nostrils and its beak. So in this way, you've always got air going in one direction through the lung. It's always fresh air and therefore, you've always got a very high oxygen gradient taking air into the tissue.
These air sacs are also making use of spaces inside some of the bird's bones including its humorous' shoulder bones and also its vertebrae. And so, that means that the bones are very, very light which the bird needs as an adaptation for flight.
How does the sun produce photons?
Dominic - The surface of the Sun is very hot of course. It's so hot that hydrogen becomes ionised into plasma so that you have protons and electrons as separate bodies, rather than bound together into atoms. As those different charges interact, they can lose energy which is radiated as the photons that we see. Now that's not actually the powerhouse that drives luminosity of the Sun. That is the fusion of hydrogen atoms into helium which occurs at the core of the Sun - in fact, only in the central 20% or so of the Sun; you have another process, which is convection, which is carrying that heat generated at the centre of the sun out to the surface to keep the surface hot so that it continues to shine.
Chris - Are there no photons being produced deep inside the Sun? Presumably there are, but they just can't get out.
Dominic - Yes. Photons are being produced all throughout the Sun; but the Sun is made of a cloudy material because the protons and electrons inside the Sun can interact with those photons. And that means the photons produced deep down can only actually travel a few centimetres before they're reabsorbed.
Chris - Brian Fulton, professor of Astrophysics at the University of York, when he was on this programme he made the point that the photons that get made in the Sun are actually a million years old plus by the time they emerge because they have spent their entire life being bombarded around and absorbed and reabsorbed, ad infinitum almost before they finally escape. So, if the Sun went out tomorrow - as in all reactions stopped - we'd still have a million years of the light locked inside.
Dominic - That's absolutely right. The light is travelling at the speed of light, but it's only hopping a few centimetres at a time and we don't know what direction it's going to come back out again. It may end up going back towards the centre of the Sun again and it takes a million years to get out. It's quite a random walk for that energy to get to the surface.
What would we see at the edge of the universe?
Dominic - Wherever you are in the universe, if you look at the distribution of galaxies and galaxy clusters around you, you will find that the sky looks more or less the same as anywhere else, and that's because you can think of the universe as being a bit like a sphere, only a three-dimensional surface of a sphere. So on a sphere, you can go all the way around and come back to where you started again. The universe is not a two-dimensional surface. It's a sort of three-dimensional surface or four-dimensional sphere if you want to think of it that way. So, wherever you are on the surface of that sphere, you've got 13.8 billion light years worth of universe that you can see in any direction, full of galaxy and galaxy clusters.
49:01 - Why does swimming pool water feel cold when it is warmer than the air?
Why does swimming pool water feel cold when it is warmer than the air?
Dave - The thing is that the temperature you feel isn't the temperature of the air or the temperature of the water, it's the temperature of your skin. If your hand is sitting in air, your body is always producing heat quite rapidly, and air is a very bad conductor of heat, so it doesn't take the heat away very fast. So even though the air might be 20 degrees centigrade, your skin might still be still be somewhere at 30 perfectly happily. Water is a much better conductor of heat, very high heat capacity, so if you put your hand in even something at 28 degrees centigrade, the surface skin is going to very rapidly get almost to exactly the same temperature as the water, so that will feel colder even though the water is warmer than the air was.
Why do I prefer to listen to music in my right ear?
Chris - What you've done Alison is to very, very elegantly demonstrate and recreate the work of a lovely lady from Canada called Doreen Kimura, who used something called the dichotic listening test to show the dominance of one side of your brain over the other in decoding language. What you do is you play two different sounds into the right and left ear simultaneously and specifically, you play language. You ask the person, "What do you hear?" Or to report what they've been listening to and you'll find they pay much attention to what's going in their right ear when it's language than in their left ear. The left ear is better at decoding music.
This is because the nervous system is all crossed over. So things that go on on the right of you get presented to the left side of your brain, things that go on on the left of you tend to get presented to the right side of your brain. So if you feed language, because your music has got lots of spoken words in it, into the right ear, most of it is getting presented to your left brain which is where your language centre is, so therefore, it's preferable to listen via that route. Beautiful question.
Do my eyes have anti-shake vision?
Chris - You can actually find the answer lurking in your inner ear on each side. It's in a system called your vestibular system and this is your organ of balance. What you have are three tiny semi-circular canals. These are actually smaller than a one penny piece each. They're a tiny canal, they contain fluid and they're orientated at 90 degrees to each other. So you have one which is a hoop going over your head towards the front, one which is at 90 degrees to that so it's going from one ear to the other, and then one like a dinner plate lying flat.
And these three together can detect the movement of the head in any direction and the rate of movement. They send signals via a nerve supply to the brain and they're connected to the nerves that control your eye movements. And so what they do, whenever you move your head in any direction, this movement is picked up by this vestibular system and it then makes your eyes move in completely the opposite direction at the same rate and amount to directly compensate for the movement of your head and this is called the vestibule-ocular reflex and it's the reason that you're going to hold a finger out in front of you, fix it up with your eyes and then shake your head backwards and forwards, and maintain a continuous gaze on your eye without everything looking shaky.
And if something goes wrong with that vestibular system, you do feel very giddy because you've lost your own built-in fuzzy logic.
58:31 - Why does dried cereal stick to the bowl?
Why does dried cereal stick to the bowl?
We put this to Peter Belton, Professor of chemistry at the University of East Anglia... Peter - The question was why does cereal stick to plates and cups and so on when it's dry? It's to do with the starch. Starch is essentially a glue. So that like any glue, it will stick things to other things. The reason starch is a glue is that it's a polymer. That means that it's very long and it has many ways of attaching itself to a surface. So when the cereal is wet, the starch sits on the surface and as it dries, the polymer gets stiffer, so it's harder and harder to pull the cereal off. When it's very dry, it's a bit like a piece of concrete and so, it sticks very hard. If you soak the material and leave it for a while, the polymers will soften up and get to be able to move again, and you'll be able to pull them off.
Diana - And are there any practical applications for this property?
Peter - Well it's used in paper paste for example and I don't know what children do at school now but when I was a kid at school, we use to make glue out of starch and water and stick things together with it. I suppose if you're desperate and you need to stick two things together, a bit of flour and water paste will actually work.
Dominic - So the starch in the weetabix is made up of very long molecules. These are suspended in the milk and tangle with each other, but as the milk dries out, starch settles onto the surface of the bowl where the parts of the starch molecule wedge themselves into microscope nooks and crannies on the bowl's surface. So now, not only are they tangled around each other, but they're also hooked into the surface of the bowl. Once it's dry, it's much harder for them to move to untangle themselves. So they form the equivalent of concrete made out of cereal. So, if you want to do the washing up without a chisel, you first have to soak the bowl, re-suspending the starch, and then the molecules can move past one another and you can scrub the bowl clean.