QnA: Temperature, Tech and Testicles
This week, we're answering your science questions, including: Are there plastics in the fish we eat? Can electrical devices affect your fertility? And how does Earth’s tilt give us our seasons? Our panel - Anglia Ruskin University ecologist Danni Green, Tim Revell from New Scientist, Bourn Hall fertility nurse Laura Carter-Penman and climate scientist James Pope from the British Antarctic Survey.
In this episode
01:05 - Let's meet the panel
Let's meet the panel
This week, ecologist Danni Green from Anglia Ruskin University, climate scientist James Pope from the British Antarctic Survey, fertility nurse Laura Carter-Penman from Bourn Hall clinic and assistant news editor Tim Revell from New Scientist tackled the questions you've been sending in. First up, Chris spoke to Danni about the problematic plastic in our oceans...
Danni - Yeah. Well I mean it's great because I've been working on plastics the last seven years and thanks to the Attenborough effect we've finally got pretty much global consensus that people are interested in this and they want to solve the problem so it's great.
Chris - How much rubbish actually is in the oceans in terms of plastics?
Danni - A lot. 320 million tons is produced every year and around 10 percent of that makes its way into the rivers and waterways as litter.
Chris - Goodness and once it’s there it just doesn’t go anywhere?
Danni - It doesn't or it breaks down into smaller pieces.
Chris - Which we're going to find out about. So Danni is here to answer any questions about marine biology and marine science and plastics in the ocean. Sitting next to Danni is Tim Revell, he is the assistant news editor at New Scientist. So you should be across lots of hot science stories. Lots things coming across your desk all the time.
Tim - Yeah we have loads of big stories all the time. Often talking about artificial intelligence or the latest technologies such as 3D printing. But one of the big ones we've had recently was questioning arguably the biggest discovery in physics in the last few years and that is gravitational waves, whether we actually spotted them or not.
Chris - Why are people skeptical?
Tim - It all comes down to the fact that it's so difficult to spot gravitational waves because even though they're caused by massive events in space, by the time they get to Earth they're very very tiny ripples. We're talking about measuring something smaller than the size of a proton. So actually being able to find them is really really difficult and involves lots of data processing and analysis and algorithms, and all of that means that it's a bit tricky for someone else to check the work of the people who've done it. And so when people have come in afterwards and had a look at what they've done they've sort of said maybe you have made a mistake and that's where the difficulty lies.
Chris - I think Bill Bryson argued that one of the smallest things in the world is some of the components in an Airfix kit! I think I'd be inclined to agree with him. Anyway Tim's here to answer your questions about things relevant to technology. James Pope is a newcomer to the programme, welcome James. He's from the British Antarctic Survey and you study climate. But why is everyone obsessing about the poles? Because no one lives at the poles really do they? So why is it important to study the poles when the majority of the world's population are not there?
James -The polar regions are just so important for climate change, you've got ice sheets which can affect sea level rise, you've got sea ice which can affect the temperature at high latitudes and maybe accelerate warming in these regions and also very important for uptake of carbon into the oceans, heat into the oceans and even the circulation, which can affect the nice warm temperatures we have in the UK.
Chris - So in other words it really matters what goes on in the poles because it does have an impact here whether we like it or not and I guess it's also a barometer for what's going to happen everywhere. If you look at what happens in the poles it's a reflection on what's happening worldwide?
James - Yes people talk about the poles as being sort of the canary in the coal mine.
Chris - Thank you very much James. And also with us is Laura Carter Penman who is a fertility nurse at Bourn Hall. I guess it doesn't take too much explanation of what fertility is, but what does a fertility nurse do?
Laura - We assist people through their fertility journey. We advise them on what is the best course of action. What is the best treatment. And we also provide quite a strong counselling role because as you could imagine for patients it's a very stressful time and we support them through that journey. If they've got a question about their fertility that they'd like to ask, I'd be happy to help.
05:20 - Are there microplastics in the fish we eat?
Are there microplastics in the fish we eat?
Steven called up asking if there are microplastics in the fish we eat. Chris Smith put this question to ecologist Danni Green from Anglia Ruskin University...
Danni - Thanks for your question Steve. Short answer is yes. There's been quite a lot of evidence finding microplastics in fish that we eat and also in bivalves animals that we eat whole because quite often the microplastics are in the guts of the animals. But actually, we found microplastics in honey, beer, tap water, bottled drinking water, pop drinks, it's in our food yeah.
Chris - Why does it matter though? I guess is that is that what what you're worried about Steve? The fact that if we're eating it we're getting a diet of plastic but does that matter.
Steven - Well, to be honest with you, I watched the programme on BBC about the plastics in the ocean where they said there were 55 trillion pieces of plastic there. So I did a bit of research myself trying to find out everything about it. Within an hour, what I found was quite horrific with oestrogen being one of the main things that was being released into the oceans, when that gets in the food chain, it's going to affect the male population as well as the female population if it's not already been doing it for the last 20, 30 years or so.
Chris - Danni.
Danni - So there is some evidence that microplastics can absorb these other persistent organic pollutants. But the evidence is inconclusive actually, because some studies have found that they can absorb these things from the water column and they keep hold of them and then they get pooped out the other end and actually stop the animal from absorbing them into their own body. And other studies have found the opposite that they release them. And given that very recently there's been evidence that microplastics are in human poo, researchers in Austria, I mean it's a preliminary study it's not a published piece of work yet so take it with a pinch of salt,
Chris - Or a pinch of plastic even!
Danni - Yes a pinch of microplastic, but it's very likely that we are eating and inhaling microplastics so we definitely need more research to find out about these other effects.
Chris - Laura, what about the point that Steve makes about oestrogens and things about these female hormones that are in water that might be picked up by these plastics and then get into our bodies. Is there evidence for that sort of phenomenon?
Laura - Yeah there is evidence out there that that is occurring, and there are higher levels of oestrogen within our waters.
Chris - Does that make a difference?
Laura - It does make a difference because it's impacting on the male factor and it's actually then leading on to reductions in sperm because its effect in testosterone production as well. So it's something that we need to be aware of.
Chris - There's evidence that some aquatic animals are also being impacted isn't there? I mean we've seen fish changing sex and so on is that through this phenomenon?
Laura - Yes that's the phenomenon, not linked to micro plastics directly but linked to the east during the water. Nonetheless from the contraceptive pill. Yeah. So fish seals so marine mammals as well and other invertebrates too.
Chris - Danni, are scientists actively monitoring this and do they have any solutions, because I know we know that there are plastics in the ocean, it's one thing to say they're there, it's another to actually do something about it. Can we remedy this?
Danni - I think in terms of trying to remove microplastics, I think it's going to be very difficult because most of them sink, so 98 percent of them sink to the benthos, to the sea floor. And obviously if you're trying to dredge them out you’re going to cause more damage than good. In terms of trying to remedy the situation, I think prevention is better than cure in this case. We need to stop putting it into the oceans. Yeah. We need to switch to safer plastics as well so BPA free which a lot of actually a lot of drinks companies have already done.
08:55 - How far are we from electric planes?
How far are we from electric planes?
Robert asks how high and how fast could electric aircraft fly, and how far away are we from actually having an electric aeroplane as reality? Chris Smith put this to Tim Revell from New Scientist...
Tim - I'd say we’re still quite a long way from the reality of flying around rather in sort of jumbo jets like they are but electric versions. That's not happening any time soon. And the problem is with electric aircraft is it just takes so much energy, to fly anything, but with an electric aircraft you need a lot of batteries and batteries are really really heavy. The heavier something is the more energy it needs so the more batteries you need. And if you've ever flown a drone you will have seen this.
You get these tiny little drones that get into the air really really quickly and a lot of fun to fly around. And eight minutes later your battery is flat. You can get some slightly bigger drones but even the big ones are there much much heavier. But even those can only fly for 30 minutes or an hour. We're talking about very short periods of time.
But that's not to say we don’t have any electric planes. There are some that have been successful and perhaps the most famous one is called Solar Impulse 2. This one had solar panels on it, was created by a Swiss team, and in 2015 it circumnavigated the globe. But the problem was it had to keep stopping and the whole journey took 16 months and it only had room for one person.
That's sort of the height as it were of electric planes at the moment. And so to answer the original question of “how high and how fast”... Solar Impulse 2 travelled at about 70 kilometers an hour, which just sort of 43 miles per hour, and was about 12000 meters in the air or about 40000 feet. In terms of height that's about the same height as a jumbo jet. We're talking similar sort of distance into the air.
But in terms of speed, a jumbo jet will easily do 500 miles an hour. It was doing 43 miles an hour. So we're a long way off at that.
但是人们会爱电动飞机because air transport is an absolutely terrible polluter of the air and it's also adding to our greenhouse gas emissions so it's also bad for the environment in many many different ways. The problem is we just don’t have good enough technology yet to make flying aircraft that would be sustainable and do the job that aircraft currently do.
Chris - It seems like all of these issues related to transport come down to batteries and energy supply. It’s like we’re at the precipice here and we really need to solve this problem. And no one's yet managed to get over this chasm of how we get enough energy packed into something that doesn't weigh more than the aeroplane at the moment and all its fuel and all its passengers. The problem is they’re just so heavy, as you say. And it’s holding back technology for phones, it’s holding back technology and other communications devices, it’s holding back technology for cars and so on.
Tim - Yeah. In terms of things like cars and even trucks and also boats, they are perhaps more promising than electric planes because the weight isn't as much of an issue. Yes, you still have to get going, but actually once you get going keeping it going is not nearly as hard as it is to keep something in the air, or to get it into the air in the first place. We’re already seeing electric cars making it onto the streets, and there are the first examples of electric trucks and also electric boats that might be able to clean up those industries before we start cleaning up planes.
12:11 - How big a problem is climate change?
How big a problem is climate change?
Geography teacher Kate Stockings asked, "how big a problem is climate change?" Chris Smith put this to climate scientist James Pope from the British Antarctic Survey...
詹姆斯——我的妻子会认同这段pedantry but I always like to say it’s never the planet. We always, when we talk about climate change, we’re talking about particularly us as human beings but also the other animals alive, the planet will carry on regardless. But ultimately, climate change will be as bad as we choose to make it.
巴黎的气候协议,你们三个ars old now, led to a pretty landmark statement and agreement from so many governments around the world and that one point five degrees Celsius warming, of which we've already had one degree of, to limit that by the end of the century would be really huge. If we can do that, probably climate change will not be that bad, very much we can adapt to that. But that will require quite a strong response. We're looking at a 50 percent cut in emissions of carbon dioxide by 2030, and then a complete removal, a net removal of all our carbon dioxide emissions so we take out everything we put in, and we don’t emit anything at all by 2050. So that's really, really, very soon when you start to consider it, you know, it's 12 years to 2030. So it's up to us really.
14:55 - Can electrical devices affect male fertility?
Can electrical devices affect male fertility?
Paul asked whether electrical devices can reduce fertility, and whether boxers are bad for your sperm. Chris Smith put this question to Bourn Hall clinic fertility nurse, Laura Carter-Penman...
Laura - Well the plain answer is yes, they can affect. There’s minimal research about, sort of, mobile phones and things like that, clearly we don’t want to be putting a mobile phone on somebody’s testicles for a month to see the effect of the sperm on it.
Chris - But aren’t we effectively doing that, Laura? If you asked most men where do you keep your mobile, it’s in their pocket, and where’s their pocket? Right next to their nether regions.
Laura - Exactly. So we would be recommending that you put it in your top shirt pocket if you have one, or your back pocket, or you know you see these people - you know, you’ve got your runners out there where they have theirs strapped onto their arms.
劳拉-我们显然喜欢的另一件事do: we’re of a generation of Netflix watchers and what have you. You know, lay in bed with your laptop and where do you put it? Slap bang on your groin, you know that’s about the worst place that you can have it. It’s all to do with heat and actually the reason the testicles hang outside the body is because sperm likes to sit at about 35 degrees where your body is about 37 degrees. So the increase in heat has a real impact on sperm production. So we want to keep the testicles cool.
Chris - Has anyone actually done the study on the laptop effect, or the warm testes effect?
Laura - There’s the warm testes effect. There has been a lot of research done on that.
Chris - Who’s at risk?
Laura - Cyclists, particularly, with their nice tight lycra. It’s not looking good for you Tim!
Tim - No, not only do I have my phone in my pocket, I cycled to the studio!
Laura - Yup!
Chris - Danni?
Danni - Can I just, it’s just a bit embarrassing; my husband is Dutch and we’ve been together for 10 years. And when my dad first met him one of the first things that he said to him was, you know, ‘What’s your bicycle seat like? Is it soft enough?’ And he said well, okay!
Laura - Well they’ve said it’s not so much about the damage, it's all to do with the wearing of the lycra, and the heat that's generated much more so than the actual damage of the cycling. There's some evidence to that, but most of it's about the fact that you wear nice cosseting shorts.
Danni - Oh he doesn’t wear lycra, it's all right then!
Laura - See he needs to be letting it all hang free!
Chris - Anatomically there are nerves that run along the bit of your body that then sits down hard on the bicycle seat aren't there? And there was a suggestion that by sitting down hard on the bicycle seat you can damage those nerves and this may affect your function. Is that not such a consideration then?
Laura - Not so much of a consideration as the heat, but it is still a consideration; as is when patients have to have surgery that involves that kind of area. Then obviously what we would usually recommend is some kind of semen preservation. Sperm preservation, because obviously it can lead to erectile dysfunction which is more the issue than the sperm.
Chris - What about hot baths and things like that? Because, you know, people love a good soak in the tub don't they. Does that have a consequence?
Laura - As long as you are probably not soaking for hours on end, you know, a hot bath now and again is not going to do you too much damage. But obviously if you are actively trying for a family we would be recommending -
Chris - Cold showers!
Laura - Showers! Cold showers!
Chris - But a cold shower could have the opposite effect, couldn’t it?! That’s supposed to cool you right down!
Laura - No, no, definitely not. Get in there together!
Chris - You heard it here first on The Naked Scientists! So Tim, hot baths for you Tim, then, is it or...?
Tim - I will be taking a cold shower as soon as I get home!
Chris - So basically the bottom line is: laptop, not on your lap then?
Laura - Yeah, laptop not on your lap, on a desk.
Chris - Mobile phone not in your pocket?
Laura - Mobile phone not in your pocket. Nice, cool, cotton boxer shorts and cooler showers, and not warm baths.
What is dandruff?
Chris Smith answered the question of why dandruff can keep coming back, from Saugat in Nepal...
Chris - Well first of all what actually is dandruff? It's very common. It's more common in men than women. It's more common under the age of 50 and it tends to have its peak onset after puberty kicks in and that probably happens because once you go through puberty your hormone profile changes and your hormone profile including testosterone and oestrogen levels affect the composition of the secretions that the glands in your skin and scalp put onto the skin surface; and those secretions include oils and other things and that in turn affects the composition of the microbes the so-called microbiome that lives on the skin.
这可能是关键,因为dandruff is flaky skin: it's dead bits of skin, which is shed all the time. But when you get dandruff what's happened is that the process by which the skin renews itself has, for some reason, speeded up. So you’re growing more skin and losing more skin and because you’re losing more skin you’re more likely to see yourself losing more skin, which is why you get these little flakes of skin.
It’s nothing to do with hygiene. It does appear to be to due to microbes because there are various conditions which are associated with it including an overgrowth of fungus. So certain fungi growing on the scalp perfectly naturally - and you often see this in young babies actually they get something called "cradle cap" - when young babies are first born you end up with a flaky skin on the top of the head and it’s probably their own microbiome first establishing itself.
你也可以如果你容易eczem头皮屑a, which is another inflammatory skin condition, or sometimes just a certain change in products like shampoos and things which can irritate the skin can cause this to happen; and then some people have got psoriasis as well and psoriasis can sometimes also cause a dandruff like phenomenon.
What can you do about it? Well you can treat it with shampoos and they often have things like zinc in them. They might have selenium in them. These are things to look for in the ingredients. Things like zinc and selenium are very good because they actually affect the microbes that cause the dandruff. Also salicylic acid, the chemical relative of aspirin, can sometimes also be in these remedies and that’s very good as well. And sometimes coal tar - in the old days people used coal tar soap: smells terrible, but it works a treat! And then there’s an anti-fungus you can rub in, something called ketoconazole, which also can be used and if you do this it suppresses the fungus that causes the dandruff.
The problem is though that, if you are prone to that particular overgrowth of those yeasts and fungi that cause it, as soon as you stop the treatment then you might get it back again and this is exactly what is being referred to in the question that it does relapse if you take away the pressure caused by the shampoo. So the best thing is, if you do get this - it's nothing to do with hygiene - people with perfectly clean hair get it equivalently with people who have dirtier hair - it’s all to do with the microbes that inhabit you and therefore the best thing to do is to find a shampoo that’s working for you and keep using it as long as it makes the problem go away.
But you know it is a pretty much a modern-era thing, because we’ve all become so obsessed about hygiene these days we tend to notice it. And I think the association with it being under 50, the cynic in me says probably because, by the time you’re 50-odd, you probably don’t care, and you might have lost your hair!
22:53 - TechYes, or TechNo: Quiz
TechYes, or TechNo: Quiz
Chris Smith puts the panel through its paces to see who'll be crowned Naked Scientists brain of the week! Team 1 - Tim Revell from New Scientist and Danni Green from Anglia Ruskin University, team 2 - James Pope from the British Antarctic Survey and Laura Carter-Penman from Bourn Hall clinic...
Chris - Tim and Danni what colour dye do you get if you boil the sea the sea snail which is called Murex? You may confer of course.
Danni - Blue?
Tim - I'll defer to Danni.
Danni - It’s really embarrassing if I get it wrong. I'm going to say blue
Chris - We’ll give you three choices. You can have red or yellow or purple.
Danni - Purple!
Bing
Chris - Yes it is a bing. Tyrian purple. It's made by boiling sea snails. The snails normally use the secretion in question to sedate their prey. It turns purple when it gets exposed to the air. It takes tens of thousands of these snails to yield just gram quantities of the dye and that's why the purple was traditionally a colour that denoted high status because it was so rare. Okay plus one for Tim and Danny, very good, you’re in the lead so far, so good. Given you only have one question and no competition.
James and Laura, a giant squid is the same length as A) a London Underground carriage, B) a mini bus or C) a double decker bus?
James - My gut says it’s going to be the longer one. I’m trying to think what’s longer, a tube carriage or a double decker bus.
Laura - My son is going to kill me, he tells me these sort of facts on a regular basis. We're going to go with the underground one do you think that's going to be the longest?
WAH WAH WAH
Chris - No, unfortunately, actually these squid - Danni you must know the answer to this do you?
Danni - Is it a double decker?
Chris - It is the double decker answer yes. They get 12 to 13 metres in length, the giant squid, double decker bus is about 12 metres so a colossal squid actually can be even bigger 15 metres. So tim and Danni in the lead so far.
Round two: round two is a matter of time. Tim and Danny; there are trees alive older than the Egyptian pyramids, is that true or is that false?
Danni - True. Because the Methuselah tree - wasn't that five thousand years old? How old were the pyramids?
Tim - A few thousand!
Danni - So yeah the Methuselah tree’s five thousand years old.
Tim - I think that's older than the pyramids. Let’s go yes.
BING
Chris - It is. There are specimens of bristlecone pine in California and Nevada and they are at roughly 5000 years old capable of predating the pyramids, the oldest of which were erected 4600 years ago. They are not the oldest living thing though there are patches of - do you know what Danny - another marine thing to put you on the spot, which are two hundred thousand years: sea grasses. Seagrasses have been documented as 200 000 years old and they live in the Mediterranean Sea. It’s a clonal organism that’s been growing there in these patches for 200 000 years.
James and Laura: can you redeem yourself? So these guys are on two, so far you've got zero. So you're doing well. Let's see if you can improve on zero. Time passes faster for your face than it does for your feet. Is this true or false?
James - Crikey! It’s all to do with gravity, isn't it? I guess gravity at your head is different to the gravity at your feet as you’re further away from…
Chris - We ’ll assume you're standing up!
James - So, I don't know. I'm still guessing either way as I’m not a physicist. What're your thoughts?
Laura - I don't know - your age shows more in your face, doesn't it? I mean that's a basic one to go with. We're going to go with face.
Chris - Time passes faster for your face than your feet. True or false. You have to give me a true or false answer.
James - Faster for the face. Face is older. True.
克里斯-逻辑是可疑的,但是答案是correct. Assuming you are standing up, Einstein’s theory of general relativity - which of course you should be very familiar with as a fertility nurse Laura - it states that the closer you are to the centre of the earth the slower time passes. At the top of Mount Everest, for example, a year is 15 microseconds shorter than at sea level. So time does actually pass a bit faster for your face than it does for your feet. You're off the bottom. Okay if they get this wrong it goes to tiebreaker if they get this right then you really are not the biggest brains of the week. Okay here we go, this round is all about technology and we want to know does this technology exist. In other words is it tech yes vs. techno. Do you see what we did there it was cool wasn't it? Okay, Tim and Danny.
Radiation blocking boxer shorts: tech yes or techno?
Danni - Maybe in Japan because they have a lot of issues with radiation don’t they, like with nuclear power plants and things…
Tim - Boxer shorts it is a weird phrase here because don't they sometimes put things in front of you if you’re having various scans to protect vital bodily organs, so they might not be boxer shorts, but they...
Danni - But they’re always inventing things. I think it might be true. They might not work.
Chris - Are you going tech yes or no?
Danni - Tech yes.
Chris - Yes! It’s unveiled at the Consumer Electronics Show this year. “Spartan's radiation blocking boxer shorts” are made from a fabric which incorporates silver fibers woven into the cotton so they block radio frequency signals from smart phones and then they can’t irradiate your privates so Laura would be very interested in this, you can refer all your -
Laura - Tim needs these clearly!
Chris - I just saw him and thought of this, that but I was thinking for your patients you could say ‘look you could get a set of these.’
The other bonus is that the silver means that the underwear is also antibacterial. So that will keep coliforms at bay in your nether regions. Well - you have lost but you want to see if you can get two points anyway? Your tech yes or no is: trip-sensitive shoes that can summon help if you should fall over. Is that a yes or a techno.
Laura - Tricky because there’s lots of technology helping tripping definitely, along with the techno theme.
James - My gran had the sort of panic buttons when she fell.
Laura - You can get things that tell you not to leave the house now for dementia patients and stuff like that.
Chris - Are you going tech yes or no?
James- I think we’ve got to go yes!
BING
Chris - Yep, E-vone have made some smart shoes. They've got the accelerometers, gyroscopes and pressure sensors in them so they can detect if you should take a tumble so they're potentially very helpful as you say for elderly people but also they have their eye on hikers and climbers whose adventures might lead them into remote locales where they could take a tumble. And apparently, these shoes come with their own sort of network subscription so they can send data and that kind of thing. So I guess you could say they come with a "running cost"!
30:23 - Do we know space better than our oceans?
Do we know space better than our oceans?
Sam got in touch to ask if it's true that we know more about space than we do about our oceans. Chris Smith put this question to ecologist Danni Green from Anglia Ruskin University...
Danni - In short I'd say yes it is. Particularly if you're talking about understanding the topography and the shape of the oceans. So for example technically we have got 100 percent of the oceans mapped but the resolution is to 5000 metres whereas we've mapped 98 percent of Venus to 100 metres resolution.
Chris - So we do know quite a bit about quite a few places but not necessarily the bottom of the sea.
Danni - But there is actually a big movement in 2017, there's a group called the General Bathymetric Chart of the Ocean GEBCO, for short and they’re launching this huge effort to map everything in more detail by 2030. And this is a big collaborative thing which would mean that ships that are out doing things for fisheries or for recreation would also be mapping the oceans using multi-beam sonar which is obviously a lot quicker than just a single beam one at a time. So there's a huge collaborative effort to map the oceans in more detail. However some ecologists are concerned that this also may lead to a huge race to try to mine the oceans more. There's lots of precious minerals down there, there's diamonds, gold, obviously oil. We're already on the oil wagon. So there's an issue there that is this going to lead to conservation or exploitation.
Chris - I wondered if you were going to say something else when you mentioned the sonar and conservation issues because there is a question as well that one of the reasons we see things like giant mammals beaching, whales driving themselves onto beaches is because of distress caused by Marine noise and underwater sound pollution.
Danni - Yes exactly. So this is another big issue. It's also associated with oil rigs and the whole process of exploration of the sea as well as exploitation.
Chris - But is sonar of the kind used by shipping. Is that destructive and disturbing to the environment and the behavior of these animals?
Danni - Yes it is, yes. There's a lot of evidence that this is interfering with their navigation systems and causing them to beach.
Chris - So it's a bit of a worry that in order to understand the ocean we could actually be doing damage
Danni - It could be disrupting even more. Yeah.
Chris - Tim?
Tim - Why is the ocean not mapped much better? you'd imagine it's much, much harder to map the surface of Venus. You know, millions of miles away than it is to map the ocean floor.
Danni - There's a lot of water in the way. Just in short, it makes it quite difficult.
And obviously there's some areas that are mapped in a lot more detail, so we've mapped about 10 to 15 percent, to 100 meters, because those are the shipping routes and the places we go to. But the areas that we rarely go to with really turbulent seas are going to be less well understood at this stage.
克里斯,我向一群海洋科学家们the University of Aberdeen a few years ago and one of them passed on the sobering fact that he ventured, not personally but with a probe, ventured to the bottom of the Pacific Ocean. It's about seven miles, 12 kilometers down, very long way down and the first thing he saw when he reached the sea bed was a plastic raincoat!
Danni - Plastic raincoat, yeah.
33:30 - Why are rising sea levels a problem?
Why are rising sea levels a problem?
Chris on Twitter asked "why are rising sea levels and melting ice caps a problem?" Chris Smith put this one to climate scientist James Pope from the British Antarctic Survey...
James - People think about the obvious, about the inundation of coastal towns and cities, but some of the less well discussed issues are around freshwater sources. So there are three types of ways we get fresh water. If you live somewhere like the Himalayas, you get it from monsoon rains and glaciers. If you live somewhere like the UK, you get it from reservoirs or aquifers. Aquifers are water storage underground in permeable rocks. What’s possible is that near coastal regions, if the sea level rises high enough it can actually flow and spill over from the sea into the aquifer, and essentially poison the aquifer by introducing a saline component, making it no longer suitable for freshwater.
Other issues, my mum lives up in Southport, and they have a lot of salt marshes up there, so that’s land that is at or just below sea level that gets inundated by the brackish water, so saline-fresh water mix, so you get an entirely different type of eco structure there. But obviously, if that inundated rice paddys, or standard arable lands here in the UK, you just lose the ability to grow crops in that are. But it's always worth saying that sea level rise is probably the least of our issues in terms of climate change. Under its most extreme scenario, we are looking at only a maximum of one metre, by 2100, sea level rise. Because the ice sheets, so that's the bits of ice that's actually on ground currently, it just takes a long time to melt. I mean if you put some ice cubes on the desk right now, they take a long time to melt and ice sheets take even longer, you’re talking several thousands of years even to get some of the more vulnerable ice sheets to completely collapse, so it's probably not a huge issue immediately.
Chris - So it's not so much the actual water movement that is the issue, it's what goes with it. It’s the mechanism that's driving the ice to melt that’s causing a rise in global temperatures, that's going to have other knock on consequences directly for the inhabited land area, rather than just a direct impact of sea level rise.
James - Yeah I would suspect that most coastal regions would see impacts from things like extreme weather phenomena. You could argue that even half a metre rise makes a coastal area more susceptible to storm surges from hurricanes or even just bad weather like we see here in the UK. So it’s not completely write-offable, but certainly it’s not some sort of dystopian flooded future.
Chris - And how much sea level rise are we looking at, probably? You said the worst case scenario might be a metre or so, but how much are we looking at, probably, if we go following the trajectory we appear to be on? And let's assume we end up with about a 1.5 degree rise across this century. What sort of sea level rise is that going to translate into?
James - So the 1.5 degree rise, the recent report that the Intergovernmental Panel on Climate Change produced on this, they estimated it would be somewhere in the region about 0.6, with an uncertainty range of about 0.3 to 0.7 of a meter. So there's an element that we're sort of committed to a certain extent. But I think from memory, a lot of that is mainly due to just the warmer planet means that actually the size of the ocean just expands, the water expands in size, so it’s thermal expansion less than actually the melt of ice sheets and glaciers.
Chris - Because the poles have melted in the past haven't they in Earth's history? We have had a planet in the past where there was no ice at either pole.
James - Yes. And conversely when we had the last glacial maximum, so about 20,000 years ago, sea level was as much as 120 meters lower. So in some respects you've had a hundred and twenty meters of sea level rise. We could, if we melted everything that was left, get another 70, but it would take an awful long time to melt everything that was left.
Chris - So that's sort of reassuring and not reassuring, all at the same time.
James - I guess it depends where you live...
37:36 - What does infertility mean?
What does infertility mean?
On the Naked Scientists forum, David asked what we mean by the word "infertile". Chris Smith directed this question to fertility nurse Laura Carter-Penman from Bourn Hall...
Laura - Infertile is actually quite an old term that was used, really. We say that couples are infertile if they've been trying for a year and haven't conceived naturally. But we would actually consider most of our patients to be something more subfertile really, that they have issues with their fertility but that can be assisted. Or mainly, there’s a lot that can be done with just lifestyle changes. Weight has a huge impact. Smoking, alcohol. Heat, we talked about. Stress factors, environmental factors. So really I think infertile is quite an old fashioned term and we should be moving to more the term of subfertile.
Chris - To what extent do you think that the rising trend in infertility is because of our modern lifestyles? We’re living life where we’re burning the candle at both ends, aren't we?
Laura - I think it has a huge impact. We like to have it all and do it all, as females you know we all want to have these amazing careers. And unfortunately our bodies don’t match with that. Our bodies still want us to be having children in our 20s and early 30s. Our bodies aren’t designed to be having babies in our late 30s and early 40s. We spend a lot of time talking about reproduction in schools and how not to have children but we don’t tell people when to start having children.
Chris - So what should we be saying then?
Laura - I think we should be explaining how you get pregnant. We need to go back to basics but we need to be explaining to people that, you know, when fertility is going to have an impact. And for women, you know, it’s 32, 33 - 35 is a real start of the cliff. And it does have an impact on men as well. You see lots of, you know, old men! You know, Mick Jagger with his hundreds of children that he seems to be having...
Chris - Allegedly!
Laura - Yeah, yeah
Chris - And that, what, gives people the impression that “I can put it off till tomorrow”?
劳拉-是的。我认为,你知道,很多老pop stars… funnily enough they all seem to have twins in their forties really easily. You know it makes you think, you know are they actually having reproductive therapy and not talking about it? So I think we should be being more honest with ourselves and more honest with the younger generation, and making it easier to be back to work. All the things that go with that, the social factors that go with that, that you can be at work and be a mum and it’s not a bad thing.
Are jellyfish immortal?
Tamsin wants to know whether so-called immortal jellyfish really exist. Chris Smith put this question to ecologist Danni Green from Anglia Ruskin University...
Danni - Yeah, so it’s not immortal in the way that in the old movie, the Highlander is immortal. So obviously not chopping off their heads and absorbing their powers unfortunately. But yeah, there is a jellyfish called Turritopsis Dohrnii, and it was actually discovered by accident, by a lazy grad student who was doing some experiments on them over the summer. And his name was Christian Sommer, and he had the medusa in the tank, which is the jellyfish form we know and love, the adult form, with the bell and the tentacles. And he left them over the summer, and he went off on holiday. When he came back he expected to find some dead medusae, maybe some polyps. All he found was polyps, which is the juvenile form. That’s the form that sits on the bottom, and that eventually grows into smaller medusae. And they are sexually reproductive, and they reproduce planula larvae and they come back down into polyps again. And all he found was polyps and he thought “that’s strange, what’s happened, where are all the dead ones, where are all the different stages?”
So then they did some experiments and they discovered that what was happening, was that when these animals get stressed, they revert to a juvenile state. So it’s a little bit like the Benjamin Button of Cnidaria I guess. So they get stressed and they can go back into being a polyp, and they can do it forever as far as we know, in a laboratory system at least.
Chris - So they transform the body of the big one, the parent for want of a better phrase, into lots of little blebby off bits, which are the polyps.
Danni - Back into one, and it’s a little bit like a butterfly going back to a caterpillar. It’s a bit like that.
Chris - But it’s also re-absorbing and redeploying all its body parts to make a totally new form of the organism?
Danni - Yeah
Chris - And not just one, but many?
Danni - Yeah so, it’s a process called transdifferentiation. And apparently, there’s talk amongst medical scientists like yourself, to use this in a way for human health, and to reduce the aging process.
Chris - But if what you’re saying is true, that these animals can just basically turn themselves back into a more primitive form of themself, there will be some jellyfish cells in the adult that turn into juvenile jellyfish cells. But when those little ones grow into big ones again, they’re going to make new cells, aren’t they? So the cells that are in there, there might be the odd cell that’s from the original parent, but they’ll have grown to make lots of newer cells. Won’t they?
Danni - Yeah, exactly.
Chris - So is it strictly immortal then?
Danni - Well it’s immortal in the sense that it can just keep going, again and again, ultimately. Not in the sense that they can’t be killed.
Chris - But a human being can reproduce, Laura will know. And you take an egg cell, that an adult has made but actually was made when her mother was pregnant with her. And that egg is then fertilised by a sperm, that one cell. You then make a whole new organism. But at the same time you’ve still made all new cells, so, you could call a human immortal then, because it’s similar in a sense to what the jellyfish is doing isn’t it?
Danni - Yeah, I suppose technically, it’s not immortal, but it’s probably the closest thing that we have on Earth that we know of to immortal perhaps.
Chris - Why do you think the jellyfish do this? Is it some kind of defence mechanism?
Danni - I think it’s a defence mechanism, it’s preservation. Now, it’s not been observed in the wild, keep in mind, because obviously this is a difficult animal to study, it’s only been seen in the laboratory. And as far as we know it can just keep doing this over and over, and even if you pinch them with a pair of forceps, they can do this within three hours. They can reduce back from the medusa stage to the polyp stage. So it happens very quickly as well.
43:46 - Will AI take my job?
Will AI take my job?
Frankie asked whether artificial intelligence could take her job, and Chris Smith put this question to Tim Revell from the New Scientist...
Tim - I guess it depends what Frankie does. It also depends on who you ask. One very famous study that looked into what jobs will be automated in the future came from the University of Oxford and they reckoned that about half of all jobs in the US and a third in the UK were at high risk of automation. Basically the job would be given to a robot at some point in the following 20 years. But since then, that study has been questioned a lot and a lot of people say it's actually lower.
It's really really hard to know what's actually going to happen in the future but I think there are some examples from history to look at. And one of the things people talk about is, “will robots actually create more jobs than they take?”. The famous example of this is the job of a bank teller, someone who you talk to at a bank to help you with your banking. Many years ago the ATM was invented and people said well that we have no need for bank tellers anymore because you go to a machine and it gives you your money and tells your balance, why would you need a person anymore?
But what happened in the next 20 years was actually it became so much cheaper to open a bank because most of the work happened at the ATM machine, that more banks were opened. And after 20 years there were more bank tellers after the invention of the ATM than there were before. some people are suggesting that automation in its current wave will have the same effect. Lots of jobs will become automated, but people will then get extra jobs on the back of that and the sort of more manual or less interesting parts of the job will be automated away. But the short answer, is we just don’t know yet.
Chris - It’s a worrying time really isn't it? Do you think scientists will always have a job though?
Tim - Asking me for a friend Chris?
克里斯,我想也可能记者我们ll because asking the hard questions and conveying it in a way that you think people are going to be interested in it, I think that’s going to be quite a tough act to match, isn’t it?
Tim - Definitely. But there are aspects of this that are already being automated. In terms of journalism, there are AIs that will look at academic papers and write them in short summaries. That’s almost my job currently. There are loads and loads of aspects of it. There are also AIs that look at, for example, social media and make a story out of that, which many journalists also make a living. I think no one is completely safe but there will be new things for us to do and perhaps the mundane aspects will be automated away, hopefully.
46:22 - What would happen if Earth wasn't tilted?
What would happen if Earth wasn't tilted?
Donald onThe Naked Scientists forumasked what would happen if the Earth wasn't tilted on its axis? Chris Smith directed this question at climate scientist James Pope from the British Antarctic Survey...
James - It’s a brilliant question. The short answer is that basically every single day would be 12 hours long, everywhere. But your latitude would affect how high the sun was in the sky. So if you're at the equator, you'd always have sort of 12 hours with a very high mid day, directly in the middle of the sky, sun. If you're at the poles, you'd have a very low right on the horizon sun for 12 hours a day. So the energy we get from the sun comes in, you can sort of imagine if you took a football or something and just put straight lines towards this football, that’s the energy from the sun. Without that tilt, all of the energy would go into the equator, there would be less energy going into the polar regions. So you'd have more energy transfer from the equator in the low latitudes up to the high latitudes, so in the mid latitudes, where we are, we'd probably get stormier, because there would just be more movement of air. And overall the UK it would probably be much like the week before Easter permanently.
Chris - What with the traffic you mean? But being more serious for a minute, so basically the temperature we experience is because it's the amount of solar input, the amount of energy falling on the land for that length of time. And so we have summer because the Earth is tilted and we see more sun during the summer period, and we have winter because we see a bit less because that part of the earth's surface is tilted away and the sun's not as high in the sky. So basically it's thanks to the fact that the Earth is tilted that we have seasons and therefore we have a seasonal climate.
James - Yes exactly.
克里斯-是的。因为有人对我说day that Mars is also tilted about, because the Earth is tilted 23 and a half degrees, Mars is tilted about the same, so therefore Mars sort of has seasons as well but it's a great deal colder than it is here on Earth.
James - Earth has got very lucky, it’s in this really nice little slot in the solar system where if we were a few hundred thousand kilometres nearer or a few hundred thousand kilometres further away from the sun it may be almost uninhabitable, and it's that sort of that variation, we're just a real sweet spot. And again, our tilt aids that, but also that tilt is what added to things like the ice ages. So the glacial interglacial cycles where huge ice sheets waxed and waned over especially northern Europe, part of that was due to the changes in the tilt and also the change in the shape of our orbit around the sun.
Chris - So why should the tilt change?
James - I don’t actually know. I think, the tilt was very early on in the earth's formation, the earth was slightly knocked off its spinning axis, so put it onto that slight tilt, and it's just got a natural wobble, like like a spinning top essentially.
Chris - And so owing to the fact that it is just gently changing that degree of inclination over very long timescales, is that why we go through phases of a bit warmer for a while, it's a bit colder for a while, and that's what people call the natural cycles, or Milankovich cycle?
James - Yeah
克里斯,所以当人们说地球一直throughout its 4.5 billion year history gone through cycles, when the climate has changed, how do we know that the warming that we're seeing today is owing to our influence and not just the earth entering another of these natural variations. Because the Earth has completely frozen up in the past, it's completely melted it's poles and been really really hot in the past hasn't it?
詹姆斯,这是最艰难的部分之一的气候science in many respects. So we have different ranges of data. Some of that is modern day satellite observations, weather stations, so it's all very new, recent, last 50 years. We have proxy data which comes from things like tree rings, the ice cores, or even sediment cores from the deep ocean, that we can go back about 65 million years for some these sediment cores. And we can look at the fossilized plankton and the chemistry of the shells we can approximate what the temperature would have been, but ultimately what we can see is that nothing has happened as fast. Nothing that we've really seen happens as fast as what we are currently observing and it's that rate of change that makes the anthropogenic effect, the manmade effect, of climate change different to natural climate change which has always happened and will continue to always happen with our signal on top of it.
50:28 - When are women most fertile?
When are women most fertile?
Sophie got in touch via Facebook to ask at what point in their cycle are women most fertile. Chris Smith put this question to fertility nurse Laura Carter-Penman from Bourn Hall clinic...
Laura - Well most women average a 28 day cycle. Some ladies have slightly shorter cycles and some have slightly longer cycles, and most ladies ovulate about halfway through that cycle so around about day 14. So from a fertility perspective, we would usually recommend regular sexual intercourse from around about day 10, because sperm lasts five to seven days and an egg will only last one to two days maximum. So ladies are mainly fertile from probably about day 14 of their cycle round to about day 21 of their cycle.
Chris - So it's all to do with ovulation occurring on day 14 but what about if a person doesn't have a regular cycle? Because the data you've given us assumes that a person knows where they are in that cycle. So what happens then?
Laura - So for us we might recommend that you have some scans so you can see what's happening, to see whether the follicle production is going on within your cycle. Patients can try using luteinising hormone sticks, those sort of surge kits as they're called. You can buy them over the counter, pee on a stick and it tells you whether you're ovulating or not. Obviously for ladies then that aren't detecting that, they may need some help with something like Clomiphene - a reproduction of a follicle stimulating hormone that usually occurs naturally but isn't in those ladies.
Chris - That encourages the chemical process of ovulation?
Laura - Yep. And then obviously we would link that again with scanning so that we can see that there is a follicle production as well.
Chris - So roughly what fraction of people do have a regular cycle, and what fraction have irregular cycles?
Laura - So probably one in six ladies have an irregular cycle, so it's quite a high proportion really. I mean we keep focusing again here on sort of, “female factor” but actually 40 percent of problems are male factor problems. 40 percent female, 20 percent sometimes sits between the ‘unknown’ and also is a mixture of two. Quite often it appears that patients are drawn together if they both have an infertility issue.
Chris - Well, they say opposites attract but not in this case! James, you were going to say?
James - Yeah I was just going to wonder, you're talking about kits you can buy over the counter… would you put any stock in the smartphone apps that sort of, suggest your fertility in the cycle?
Laura - Yeah there's lots out there now which help you track your cycle. They would recommend that you track your temperature because there's supposed to be a slight temperature rise when you ovulate. There's now a bit like FitBits and things like that they're now out there for fertility as well. That is a big sort of up and coming burgeoning market within that side of things as well.
Chris - Do people say they find these things useful, or do you think it just helps to focus their mind? They get a plan in place so then they tend to stick to it which means they're more likely to be successful?
Laura - For some patients it's really helpful, it gives them a focus. For others it just absolutely adds to the stress of the situation and we would recommend that they go and seek help from a specialist and see their GP, speak to a fertility nurse. There's lots of things out there to help and actually the apps are useful but I think sometimes for patients who are really struggling it's not the best thing it really adds to their stress.
Chris - Some people use these apps because they don't want to get pregnant. Is that a risky strategy then?
Laura - I would say it's a very risky strategy!
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