What's between my internal organs?

Chris Smith put this to physicist Andrew Norton from the Open University...

Andrew - The short answer is no, but I think you want a longer answer. We've got to understand the Earth is rotating and if we take the equator of the Earth, that's about 40,000 kilometers all the way round, and the Earth rotates once in every 24 hours. So if you're on the equator, you're moving at about 1,670 kilometers per hour. And here, a little bit further north, we're moving a little slower than that but nonetheless, we're moving very fast as the Earth rotates.

So, if you do decide to hover with your jetpack, or whatever it may be, then you've already got that sort of sidewise motion, whether or not you're hovering or standing on the Earth. So you and the buildings will continue moving sideways east to west at that same speed so, no the building wouldn't crash into you. You and the building would keep moving, keep rotating round the Earth with the speed that you've got.

I guess what you're thinking of maybe is if you could somehow take away that rotational speed that you've got by giving yourself an equivalent speed in the opposite direction, then that could well do it. But you'd have to work very hard to give yourself that extra speed in the opposite direction to cancel out the rotation that you start with.

Chris - A flight time to America is different in duration to a flight time from America though for the reason the Earth is turning to an extent, isn't it?

Andrew - It's partly because the Earth's rotating, partly also it's affected by the high altitude winds that either give you til wind or a head wind on the plane. But yes, the rotation of the Earth does make a difference to that.

We put this to Chris Smith, from the Naked Scientists...

Chris - I think it is a very personal thing and I think it's a habit. I don't know, I don't think there's a straightforward answer to this question. Certainly it's something I think you probably can practice and I have heard some real screechy people. I mean, you must have all heard people with this kind of laugh from hell. There was one woman I remember, I was at this holiday place and there was this lady with this laugh that sort of went - she almost sounded like she was being strangled. So she would laugh and then there would be this huuuh... huuuh noise between bouts of laughter. And I'm sure that it must be just a rehearsal thing, you get into a habit of laughing that particular way. I don't know for sure, but I suspect if you did practice you could certainly, in the same way as you can change your accent and the way you speak, you could certainly, I think, change the way that you laugh. Georgia - And laughters such a strange thing. Something to try at home that's really funny is to laugh but try not to smile. It's so strange because laughter is such an automatic reaction. If you try and just keep you face sad and then laugh, honestly it's.

Chris - Do you make yourself laugh doing it?

Georgia - Yeah, yeah. The room will go into hysterics because it's such a weird thing to do, but yes.

Peter - Haw haw haw - it sounds like Father Christmas.

Georgia - It's really difficult.

Chris - Father's Christmas has come early. There you go. So send in some samples of your laughter and we'll play them on the programme and maybe the best one will win a prize.

Chris Smith put this to zoologist and naked scientist Georgia Mills...

Georgia - Well firstly, may I suggest investing in a bin if you want to avoid this in future. I actually had a look on.

Chris - Sounds like he doesn't needs one. It seems like he has a sort of natural...

Georgia - . cleaning ants, yeah. Well, actually, I looked online and there's quite a few people have noticed this. People from all around the world are saying what is going on here, why do ants really like toe nails - it's a bit disgusting really?

So nails, they're made of a protein called keratin. It's the same thing your hair is made of and it's a protein. So there is nutrients in proteins, but the thing about keratin is it's notoriously difficult to digest. There's only a few species of insects that we know can digest keratin and ants, as far as I can tell, aren't one of them.

So what are they doing with it? It could be that these ants are making a terrible mistake because, if you think about your fingers, you're touching food a lot, there's dead skin cells under them, there's bacteria. It could be that there's a smell that they're very attracted to. So they think oh, there's a nice bit of food, taking it back, and then they're like oh no, we can't eat this, what have we done! We've wasted so much time!

There was one theory that I read that was quite interesting. So something we know that can digest keratin is fungus and a lot of ants are known to have these relationships with fungus where they kind of grow it as farmers and then they eat the fungus. So it could be they're putting the nails on the fungus, the fungus is getting energy from it and then the ants are benefitting from that. But, these funguses only exist in the Americas, and I think people have been reporting this from all over the world, so it must be something else going on. And I think some people have reported that ants have been seen harvesting keratin from dead bodies as well. So maybe there's a PhD in this, maybe they are digesting the keratin and there is some process we don't know about yet.

Chris - When I was wondering around in Zambia in the Luangwa forest, there were lots of remains of animals dotted about, horns and things and they all did have holes in them. And I asked the guide what had made these holes because the horns of animals are keratin aren't they and he said well, actually, certain moths will come in and lay eggs on the horns because the moths, in the same way as they eat your clothing in your cupboard, that's why you get holes from clothing moths - they do have the ability to break down and digest these horns. That wasn't ants, it clearly wasn't ants.

Peter.

Peter - Yes, keratin is also in hair isn't it - is that right?

Georgia - Yes. Which is why it's a very bad idea for you to eat balls of your own hair.

Peter - But are the ants interested in hair?

Georgia - I did actually search that and apparently not. But the keratin in your fingernails and the keratin in your hair are different structures, so maybe that's got something to do with it.

Chris Smith put this to climate scientist Doug Crawford-Brown from the University of Cambridge...

Doug - Yeah. The first thing I'll say is we just don't know, either on the IPCC or on the UK Climate Change Risk Assessment Committee, we don't know the exact timing of this. It's probably something around 2050 to 2080, somewhere in that range. There are some people, even in the scientific community who think we're already there, we're already seeing inconvenience in the weather. I don't happen to be one of those people. I do happen to be one of those people who think that by 2050 and 2080 will really start thinking about this. I'm already making a list of people who have been climate deniers so that in 2050 and 2080 I can roll that list out and say, "whatever were you thinking of." But, of course, most of them are about my age and they'll be dead by that time so I'll have no glee at all.

Chris - You're clearly a glass half full man aren't you?

Doug - Yeah.

克里斯-安德鲁。

Andrew - Yeah, I was just wondering, linking back to the last question as well. If the icecaps were to melt completely, what change would that make to the global sea level?

Doug - Well it raises it by hundreds of metres.

Andrew - Hundreds of metres?

Doug - Hundreds of meters, yeah. So you flood almost all the coastal areas.

Chris - Of course, not the North Pole because that's floating ice, which means it's already displaced it's own mass already so that's not going to change a lot. But what's on Greenland? I mean Greenland alone adds, potentially quite a big rise in sea level, just Greenland, doesn't it Doug?

Doug - Tens of metres, yeah.

Chris - Yeah, and the Antarctic's interesting. I read a paper where they were actually looking at the gravitational effect of having that much mass, even though in the Antarctic the ice is on land so it's not displacing water. It is nonetheless, gravitationally active so it attracts a big bulge of water around the bottom of the planet holding the water down there, so it's not washing around up here and, therefore we have artificially lower levels of sea than we would otherwise have were that to be released. And, if we melt that, obviously then that water's going to redistribute and we'll see higher sea levels. Georgia...

格鲁吉亚——之间的特朗普想要建造一堵墙USA and Mexico. If a wall that big could you just build one around Greenland and just keep all the water in there?

Doug - Mexico, by the way, have said they're going to build the wall to keep Trump out of Mexico.

Chris - But what's the carbon footprint of that concrete, because 40 percent, isn't it, of CO2 emissions worldwide are just making cement?

Doug - That's right, there's a large carbon footprint to making cement. However cement, when put into buildings and so forth, then reabsorbs carbon dioxide. So, about half of that will be reabsorbed during the process of making something.

Chris - But you've still got to run the furnace to boil up the limestone in the first place.

Doug - I have no idea how big the carbon footprint is of the Mexican wall.

Chris Smith put this to zoologist and naked scientist Georgia Mills...

Georgia - Hello Heath. Hello Bertie. So there's a few things there. How come dogs don't catch colds? Well, they can get something very similar to a cold with similar symptoms to us but they cannot catch our equivalent of a cold. So the virus that affects us is very specific and will only attack us, and we won't be able to transfer it dogs and vice versa, It won't come back the other way so you can't catch a cold off your dog.

And then so why does he get in these lakes and not get a cold. So swimming in an icy lake in itself will not give you a cold. You need to come into contact with a virus to actually come down with it. Swimming in icy lakes can harm your immune system, so it might make you more likely to catch the cold, but it won't give you one.

So why don't dogs seem to get ill that often? Well firstly, they can't tell us when they are ill and...

Chris - Do you know what they say if they do?

Georgia - Are they feeling "rough" Chris? I saw that one coming.

Chris - You know me too well!

Georgia - And the other thing is, if you think about how many people you bump into in a day on your commute at work, at home - so many people. Dogs do not have that level of interactions with other dogs. There's not enough of them for these diseases to proliferate that much. And, in fact, one of the diseases like a cold that a dog can get is kennel cough. So called because they often get it when they're in kennels where a lot of them are in the same place. So, the fact that Bertie isn't in a kennel, he's free to enjoy these icy lakes and probably will be fine.

Chris - We published an article on The Naked Scientists a few years back now. It was called "Can my Dog Give me Diarrhea." Because people are actually looking at the viruses that cause diarrhea in people. Noroviruses are very common causes of diarrhea; they cause millions of cases in humans, but dogs have their own forms of noro call calici viruses.

And there's some evidence that dogs, if you recover dog poos from your pet and analyse it, and people have done this study - very dedicated scientists - you can see that the same norovirus is in the person as in the dog, but there's no evidence that the dog was symptomatic with the infection. So it might be able to pick up it's owners infection but probably doesn't become symptomatic with it. But people are looking. They've doing a study to recover dog turds and compare them with owners with symptoms and see if there's any evidence linking the two.

We put this question to tech investor Peter Cowley...

Chris - Here's one for you Peter: this might be a potential new money-spinner for your business arsenal who knows? This is a question from Jules who wrote to us to say:

Could we install and use microwave technology for domestic central heating systems, to heat the water and radiators in the home, cost effectively?

Peter - Yes, thank you, yes. This amused me quite a bit because I actually misread it to start with and I thought could a microwave be used to heat a home? And I thought Um, you could put the microwave around the home.

Chris - It wouldn't look so good in the fireplace though would it?

Peter - Well actually the other way round. So yes, interesting idea actually because we use microwaves for heating small items very, very effectively compared with putting them on the stove, but it isn't going to work for a number of reasons.

First of all based on a consumer microwave it's actually very inefficient. Its at the order of 70 percent efficient and that means that for every kilowatt, 300 watts are disappearing in heat.

Secondly, the cost. My own gas boiler at home is 91 percent efficient compared with 60 or 70 percent and it works out about £35 a kilowatt. Whereas a microwave would probably cost about £100 to £150, so it's about four times more expensive.

Thirdly, and a very big one here, at the moment with the consumer microwaves the MTBF, which is the mean time between failures, is only about 2,000 hours. So 2,000 hours is about 12 weeks of heating so you'd have to change your "boiler" every 12 weeks. A boilers about the order of about 10 years, we hope, but probably a bit less nowadays, but that's 88,000 hours compared with 2,000 hours. And so, it works out because of that reliability the capital cost is about 100 times more.

然后最重要的是,电源气体, which my boiler is, is about 3 or 4 times cheaper per kilowatt hour than electricity. So, all in all, something very major would have to happen or destructively change in order to use a microwave to heat the water in a house.

Chris - Georgia.

Georgia - I have a question about the waste. You said there was about 30 percent wasted energy but it was wasted as heat. Surely that's not a problem if you're trying to heat things.

Peter - No, that's right. But it's heating in the environment where the microwave is, so you'd actually also have to cool and take water through that air as well. But you're right, that is converting electricity.

We put this to Naked Scientist Chris Smith...

Chris - Right. We've got this question from Luke:

What is in between the internal parts of the body. I'm assuming it can't be air or blood which would get stale and prone to infection due to lack of circulation. It's not going to be a vacuum, and I doubt that the organs are all jammed in with absolutely zero space. So what is in there? Chris - What do you reckon Georgia - what's in there?

Georgia - in between? Jelly.

laughter

Chris - In my case I think it's expanding amounts of flab. But the answer is, we know the answer to this rather well because we've actually got very good imaging modalities now. We've got CT scans, we have MRI scans, we have X rays and so we can see what's inside a body when it's in its intact state.

答案是,实际上,没有自由gas inside your body unless you have a problem. If you do a chest x ray on somebody you can see where the gas is in their lungs and you can also see that the lungs go right out to the chest wall and there's no gas outside the lungs. Now sometimes people get a condition called a pneumothorax, and this is where the lung pops and you get air outside the lung, and doctors looking at an X ray of the chest would see that there's a bubble of gas around the lungs and you can see that it's clearly where it shouldn't be.

也是一样的腹部。内脏,如果you actually look inside the abdomen actually most of the stuff in their, your guts and all the internal organs, they're all slippery and slimy and covered in water. But they're very closely packed in and sliding past each other and there is no free gas in there.

如果你do a chest X ray on somebody, you do this to diagnose abdominal problems because you do a chest X ray with someone upright and you can see where their diaphragm is and you can see a bubble of gas forming under the diaphragm. And that's always pathological and shows they've had some kind of rupture of one of their internal organs, or that a nice surgeon has been in there and done something recently and left some gas in there. Because when we do laparoscopic surgery, when they put a camera in, actually what you do is to put a needle in and you blow up the person's abdomen with carbon dioxide and inflate their tummy, so that it lifts the abdominal wall away from the internal organs and that way, when you put your instruments in to start with you don't do damage and you also create space for yourself in which to work. And you use carbon dioxide because it's easy for that to be reabsorbed into the body. It dissolves back in your body fluids and then it disappears off through your lungs. Peter.

Peter - Isn't there something called peritonitis? Isn't that something where there's an infection within the abdomen - what is that?

Chris - Well, peritonitis is where you have infected the layers around your peritoneum. Your peritoneal cavity is your abdominal cavity, and if things get out of your intestines and into that space, they set up peritonitis inflammation there. You can also get chemical inflammation of the peritoneal space but, on the whole, that's always pathological, and it can also be because of say, cancer. That can do that too. Doug?

Doug - Just quickly because we have two physicists in the room here. I think we would point out that the vast majority of the things in our body are, in fact, empty space between the nucleus and the electrons. So, we are mostly not there at all.

Chris - I thought you were going to say like in some people's heads there's quite a gap as well. Your non-adopted county's newly elected president has something going on in that department, doesn't it.

Doug - I can see a theme developing here! So the audience knows I am British now, okay.

Chris - To summarise the question: what's inside a body. Well the answer is that there is no free space, there is no wasted space, and it's largely fluid and things all in a position with each other. But where you do end up with a whole or something that's no there you do sometimes get a bubble of gas and doctors can spot that, and they know when they see that that there is something going wrong.

Chris Smith put this to climate scientist Doug Crawford-Brown from the University of Cambridge...

Doug - Yeah, we've packed a lot of questions in there. When I was born there were 2.5 billion people on the Earth, and I'm not that old.

Chris - Is that back when you had your first Brontosaurus?

Doug - When I hear that fact, I fell off my dinosaur, yeah. If we were to go back to that number of people - problem sorted. Every time we discuss this at the conference of the parties meetings on climate change, it gets into a big argument between the United States saying "well, you China produce more CO2," and China saying "but we have more people," and the United States saying "oh, but your are producing more CO2," and back and forth.

So population has been on the table for a long time. People worry about discussing it simply because it causes such discord between the developed and developing nations.

Chris - I suppose it's a hard nut to crack isn't it, because you've basically got to tell people how many kids they can have, which has always been something people have regarded as an almost God given right, isn't it?

Doug - In the US, I used to go round to churches and give these presentations. And every time I would talk about climate and talk about all sorts of mitigation measures, which is what the first half of the question was, everybody was fine. The minute I talked about population control, the response was uniformly 'God will tell me how many children to have' and I just learned to back away from that.

What can we do to make the changes? The example I always use is on the 7th of March, 2008 at 07.05 am, my carbon footprint went down by 60 percent. And I'm always asked by people "well what happened" and well, what happened was that was the time at which my wife and myself and my son migrated from the US to here. Any my life in Cambridge is just as good as my life in Chapel Hill, North Carolina, but it's 60 percent less CO2. Smaller house, we don't drive a car, because you can't really drive one in Cambridge, and so forth. So those are the things: make your house smaller, make your house a little bit cooler in the winter, and so on.

Chris - You say cooler in the winter. Do you mean like fairly light, Christmas lights, that kind of thing? Georgia.

格鲁吉亚——实际上说到圣诞节,那t is like if you think about reducing the amount of waste, Christmas has so many things that we just throw away immediately. Think about crackers - you pull them and they immediately go in the bin. Wrapping paper - so much paper that is there to look nice. So things like recycle so boring - recycle your wrapping paper and things like that.

Chris - But you raise a good point about wrapping paper because I was pretty horrified when I just didn't put the bin out for a couple days at home, and I looked at how much packaging, like plastic packaging, that everything. You cannot buy something these days without it coming with impenetrable layers of plastic packaging. What's with that?

Peter - The Germans started about 25/30 years ago when I was living there they changed that quite a bit. There wouldn't be much packaging and you would take off the packaging before you left the supermarket. Obviously, you're taking a risk then that you damage an item on the way home but the reduction in packaging, I assume they're still doing it, was considerable compared with other countries.

Chris - So Doug, just wrap up the question then. Could you give us a little checklist of say your top five tips for what Heath, and the average person, can do to cut their carbon footprint.

Doug - Well, the biggest one, by far, is how much temperature you have in you house and turn the thermostat down if you even have a thermostat - a 3 or 4 degrees centigrade temperature drop.

Number two. Don't do what I do, which is fly all over the world and lecture people about how they can reduce their carbon footprint.

Chris - About climate change.

Doug - I think St Peter and I are going to have a conversation about that at some point in time.

I mean number three is consumption patterns. And, ultimately, I think people need to understand that they are the ones driving this system. You know, quite blaming the producers, the companies, the countries that produce this stuff. We turn that system on every time we consume refrigerator, computers, and so forth.

That's not five, but it's three.

Chris Smith put this to physicist Andrew Norton from the Open University...

Andrew - This is a great question - I love this. The thing you've got to realise is that mirrors aren't 100 percent efficient. A typical mirror will only reflect 90 percent of the light that falls on it. You can get better quality ones that will reflect more. But say your mirror reflects 90 percent of the light, that means 10 percent of the light is absorbed on every reflection, and that heats the mirror up and that sort of thing.

So, if you've got to reduce the amount of light by one part in a billion of what you started with, that will only take 200 reflections. So the light bounces backwards and forwards 200 times, and you're already down to less than one part in a billion of the light you started with.

Now if you've got a typical sized room like this studio we're in - it's a few meters across. The light bouncing backwards and forwards 200 times would take maybe 2 microseconds, 2 millionths of a second. So, within 2 millionths of a second, the light bounce backwards and forwards 2 hundred times and you're down to one part in a billion. That's why it gets dark.